TY - CONF A1 - Holtappels, Kai T1 - Safety Aspects for Hydrogen Technologies - H2Safety@BAM N2 - Hydrogen is a central component of the energy transition and the European Green Deal for a climate-neutral Europe. To be able to achieve the targets defined by 2045, the EU and the German government have drafted a framework for action and are making long-term investments in research, development and the rapid implementation of innovative hydrogen technologies. The conditions for a successful energy transition and the economic use of green hydrogen as a clean energy carrier are Hydrogen readiness and a rapid market ramp-up, as well as the establishment of the necessary value chains in the national and European framework. Reliable quality and safety standards are the prerequisite for ensuring safety of supply and environmental compatibility and for creating trust in these technologies. BAM has bundled its expertise in the field of hydrogen technologies into a competence center H2Safety@BAM to create confidence in the technology and to support the hydrogen strategies of the German government and the EU. The topic of hydrogen has been current at BAM for more than one hundred years and is also currently the focus of numerous research and cooperation activities. The competence centre H2Safety@BAM and its vision of “We build trust in hydrogen technologies” will be presented with its many safety-related topics, which can be found throughout the entire hydrogen value chain. Two deep dives will present the results on projects dealing with the design-to-cost issue of classical pressurized gas storage containments and the consequences of the release of liquid hydrogen, which will be roughly compared to the release of ammonia. T2 - 25. Kalorimetrietage CY - Braunschweig, Germany DA - 31.05.2023 KW - H2Safety@BAM KW - Safety KW - Hydrogen KW - Gas cylinders KW - DELFIN KW - LH2 KW - Hydrogen release KW - Rapid phase transition KW - Consequences KW - Cyro storage tanks PY - 2023 AN - OPUS4-57629 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krankenhagen, Rainer A1 - Röllig, Mathias A1 - Worzewski, Tamara A1 - Doroshtnasir, Manoucher T1 - Thermographic rotor blade inspection from larger distances – a promising tool for the maintenance of wind turbines N2 - The permanently increasing number of wind turbines requires suited inspection and monitoring methods to ensure liability and security. Concerning the inspection of ro-tor blades, only manual inspections are state of the art. Thermographic Testing (TT) has the potential to detect typical failures and damages on rotor blades. The paper presents some results of onsite measurements carried out as “passive thermogra-phy”, i.e. without a defined heating procedure. Due the totally contactless meas-urement principle, TT can be applied to rotating blades as well as to resting blades. Both methods will be compared with respect to their possible realization. T2 - WCNDT 2016 CY - Munich, Germany DA - 13.06.2016 KW - Wind turbine rotor blade KW - Thermographic inspection KW - Passive thermography KW - Nondestructive testing PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366331 SN - 978-3-940283-78-8 SP - We.4.D.4., 1 EP - 8 AN - OPUS4-36633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Anita T1 - Lithiumbatterien: Anforderungen für die Beförderung von beschädigten Batterien und Überblick über die UN TDG Arbeitsgruppe zur gefahrenbasierten Klassifizierung N2 - Lithiumbatterien: Anforderungen für die Beförderung von beschädigten Batterien und Überblick über die UN TDG Arbeitsgruppe zur gefahrenbasierten Klassifizierung BAM ist beteiligt in den Arbeitsgruppen und stellt eigene Prüfergebnisse vor. T2 - IAA 2022 Transportation, Gefahrguttag des BMDV, "Aktuelle Entwicklungen im Gefahrgutrecht und Erhöhung der Sicherheit von Gefahrgutfahrzeugen" CY - Hannover, Germany DA - 21.09.2022 KW - Lithiumbatterien KW - Energiespeicher KW - UN TDG Lithiumbatterien PY - 2022 AN - OPUS4-56742 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Anita T1 - Herausforderung: Verpackungen von Lithiumbatterien N2 - Je nach Zustand bestehen unterschiedliche Anforderungen an Verpackungen zum Transport von Lithiumbatterien. Hierbei sind bestimmte Prüfungen und Kriterien zu betrachten. Aktuell besteht insbesondere der Bedarf an Verpackungen für kritisch defekte Batterien. Innovative Lösungen sind gefordert. T2 - Workshop AG Future Markets New Energy Packaging CY - Online meeting DA - 12.03.2021 KW - Lithium Batterien KW - Gefahrgutverpackungen PY - 2021 AN - OPUS4-54181 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Winckelmann, Alexander T1 - Investigation of degradation of the aluminum current collector in lithium-ion batteries by glow-discharge optical emission spectroscopy N2 - Lithium-ion batteries (LIBs) are one technology to overcome the challenges of climate and energy crisis. They are widely used in electric vehicles, consumer electronics, or as storage for renewable energy sources. However, despite innovations in batteries' components like cathode and anode materials, separators, and electrolytes, the aging mechanism related to metallic aluminum current collector degradation causes a significant drop in their performance and prevents the durable use of LIBs. Glow-discharge optical emission spectroscopy (GD-OES) is a powerful method for depth-profiling of batteries' electrode materials. This work investigates aging-induced aluminum deposition on commercial lithium cobalt oxide (LCO) batteries' cathodes. The results illustrate the depth-resolved elemental distribution from the cathode surface to the current collector. An accumulation of aluminum is found on the cathode surface by GD-OES, consistent with results from energy-dispersive X-ray spectroscopy (EDX) combined with focused ion beam (FIB) cutting. In comparison to FIB-EDX, GD-OES allows a fast and manageable depth-profiling. Results from different positions on an aged cathode indicate an inhomogeneous aluminum film growth on the surface. The conclusions from these experiments can lead to a better understanding of the degradation of the aluminum current collector, thus leading to higher lifetimes of LIBs. T2 - Adlershofer Forschungsforum 2022 CY - Berlin, Germany DA - 11.11.2022 KW - Lithium Ion Batteries KW - GD-OES KW - FIB KW - SEM KW - EDX PY - 2022 AN - OPUS4-56246 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Böttcher, Nils T1 - Sicherheit von Lithium-und Natrium-Batterien - Brandprüfungen und Sicherheitsmaßnahmen N2 - Die Präsentation gibt einen ganzheitlichen Überblick im sicheren Umgang mit elektrochemischen Energiespeichertechnologien. Ferner enthält diese Präsentation einen Überblick über die aktuell an der BAM durchgeführten Forschungsprojekte und hoheitlichen Aufgaben mit Bezug diesen Energiespeichern T2 - Lehrgang "Moderne elektrochemische Energiespeicher" (905350) CY - Mannheim, Germany DA - 16.09.2024 KW - Lithiumbatterien KW - Thermal Runaway KW - Sicherheit KW - Natriumbatterien PY - 2024 AN - OPUS4-62302 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tichter, Tim T1 - Electroanalytical experiments at macroporous electrodes for redox-flow batteries N2 - Macroporous carbon felts (CFs) are the prevalently used electrode material for redox-flow batteris. Owing to their large internal surface area, these structures can efficiently drive the Faradaic reactions in a RFB. However, the electrochemical characterization of novel CFs, or modified CF-materials is a cumbersome task. This is essentially related to the complex mass-transport phenomena which are convoluted with the electrode kinetics. This talk will focus on ex-situ cyclic voltammetry and operando electrochemical impedance spectroscopy as electroanalytical techniques for porous RFB electrodes. Common pitfalls in the voltammetric analysis of CFs are elucidated and recent strategies for modeling and evaluating CV experiments on porous structures are introduced. Finally, a method based on electrochemical impedance spectroscopy is introduced which allows for an operando fingerprinting of electrochemical reactions in a vanadium-based RFB. T2 - Flow4U-Event CY - Eindhoven, Netherlands DA - 08.04.2024 KW - Porous Electrodes KW - Redox-Flow Batteries KW - Digital Simulation KW - Convolutive modeling KW - Impedance Spectroscopy KW - Distribution of Relaxation Times PY - 2024 AN - OPUS4-62304 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tichter, Tim T1 - The DSDC Algorithm - A Universal Strategy for Simulating Voltammetry of Rough and Porous Electrodes N2 - Porous electrodes or electrodes with rough surfaces offer a multitude of tailored applications. The theoretical treatment of such structures is, however, challenging since their voltammetric profile is a convolution of the time-dependent current with an inherently random mass-transfer function. Since the latter quantity has no analytical solution, the classical convolutive techniques cannot be applied. Therefore, simulations have been based on severe simplifications of the diffusion space [1,2] or were performed by means of digital simulation. Unfortunately, the latter approach becomes computationally prohibitive when a large and/or highly resolved, three-dimensional diffusion space needs to be considered. To mitigate these problems, we introduce the digital simulation, deconvolution, convolution (DSDC) algorithm, consisting of four successive steps [3]. Firstly, the three-dimensional image of the electrode under investigation is extracted via micro X-ray computed tomography (µ-CT) or atomic-force microscopy (AFM). Subsequently, the purely mass-transfer controlled current of this spatial template is generated by means of digital simulation. In the third and fourth steps, the mass-transfer function is extracted for a set of discrete points in time by numerical deconvolution and finally used for classical convolutive simulations. In this manner, any simplification of the diffusion domain becomes obsolete and the advantages of digital simulation and convolutive modelling are most favourably combined. Finally, this DSDC-algorithm provides an interdisciplinary connection of ex-situ imaging and in-situ electrochemistry which results in excellent agreement of simulated and experimentally acquired data. T2 - Bunsentagung 2024 CY - Aachen, Germany DA - 25.03.2024 KW - Porous Electrodes KW - Convolutive Modeling KW - Digital Simulation KW - Diffusion KW - Redox-Flow Batteries PY - 2024 AN - OPUS4-62303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rethmeier, Michael T1 - Anwendung einer Kombination aus Laserhybrid- und Unterpulverschweißen zum Fügen dicker Bleche aus Schiffbaustahl EH36 N2 - In diesem Beitrag wird ein Schweißverfahren vorgestellt, mit dem 30 mm dicke Bleche aus Schiffbaustahl EH36 effizient und werkstoffgerecht gefügt werden können. Die wirtschaftlichen Vorteile des Verfahrens ergeben sich aus dem Wegfall der aufwendigen Kantenvorbereitung und der Reduzierung des Schweißzusatzbedarfs. Die Stumpfschweißnähte werden in einer Lagen-/Gegenlage-Technik durch Laserhybridschweißen und Unterpulverschweißen ausgeführt. Dabei erfolgt die Laserhybridschweißung als Einschweißung mit einer Tiefe von etwa 25 mm, während die Unterpulvernaht als zweiter Durchgang auf der gegenüberliegenden Seite des Bauteils mit einer Einschweißtiefe von 8 mm aufgebracht wird. Die Überlappung der beiden Lagen gewährleistet einen geschlossenen Nahtquerschnitt. Dank der partiellen Durchschweißung der Laserhybridnaht entfällt die Notwendigkeit zur Wurzelformierung. Darüber hinaus bietet die Prozesskombination eine höhere Toleranz gegenüber Ungenauigkeiten in der Kantenvorbereitung, was die Prozesskomplexität reduziert. Der Einsatz dieses robusteren Verfahrens, das weniger von einer präzisen Kantenvorbereitung abhängig ist, erleichtert die Produktionsvorbereitung, minimiert die Fehleranfälligkeit und senkt die Nachbearbeitungskosten. Dies macht das Laserhybridschweißen besonders attraktiv für Anwendungen im Schiffbau. T2 - 22. Tagung Schweißen in der maritimen Technik und im Ingenieurbau CY - Hamburg, Germany DA - 13.05.2025 KW - Kerbschlagbiegeversuch KW - Laserhybridschweißen KW - Unterpulverschweißen PY - 2025 AN - OPUS4-65073 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Leonhardt, Robert T1 - Impedance-based characterization of the overstress-related degradationin alkali metal-ion cells N2 - The successful repurposing of degraded alkali metal-ion batteries in second-life applications is a vital step towards achieving a circular economy. While reusing aged cells is a promising way of mitigating their overall environmental footprint, it is crucial to anticipate their future safety and performance characteristics. Unfortunately, predicting these properties is a cumbersome task, essentially caused by limited knowledge of the interference of different degradation modes in the cells’ first life. To still enable estimating of these parameters from a current state, the present study systematically investigates the impact of abusive conditions in an early phase of the cells’ life on their subsequent degradation behavior. For this purpose, individual lithium-ion and sodium-ion cells are initially stressed by different measures such as deep-discharging, high-temperature conditions, and deliberate combinations of the aforementioned methods. Electrochemical performance indicators are monitored during subsequent cycling of the cells, which provides insights into the interdependencies of different degradation modes induced by specific stress conditions. In this manner, it is clarified whether or not the total degradation can be determined by a convolution or a superposition of individual deterioration effects and thus, be described as a multidimensional state function. This knowledge will finally contribute to a better understanding of the performance and safety behavior of degraded batteries which can help to successfully implement them into second-life applications. T2 - Doktorandenseminar der Technischen Universität Berlin CY - Berlin, Germany DA - 30.09.2025 KW - Alkali metal-ion batteries KW - Electrochemical performance indicators PY - 2025 AN - OPUS4-65068 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Böttcher, Nils T1 - Lithiumbatterien, Natrium-Ionen Batterien, Festkörperbatterien - Wohin geht die Regelwerksentwicklung? N2 - Der Markt für Energiespeicher befindet sich in einer Phase intensiver technologischer Diversifizierung. Neben etablierten Lithium-Ionen-Batterien gewinnen neue Systeme wie Natrium-Ionen-Batterien und künftige Technologien wie Festkörperbatterien zunehmend an Bedeutung. Dies stellt jedoch neue Anforderungen an die Handhabung und Logistik respektiver Systeme und rückt die Klassifizierung von Batterien nach Gefährlichkeit stärker in den Fokus. In diesem Kontext gilt es Transportprozesse zu vereinfachen und simultan die Sicherheit zu erhöhen. Im Rahmen dieses Vortrags werden aktuelle und kommende Batterietechnologien vorgestellt, die essenziellen Hürden bei deren Handhabung, Transport und Lagerung zusammenfassend dargestellt und ein umfassender Ausblick auf die Regelwerksentwicklung gegeben. Schwerpunkte liegen dabei auf I) der Entwicklung dedizierter Methoden für die Einordnung in Kategorien defekte und kritisch defekte Batteriesysteme, II) Passivierende Verfahren (thermisch und/oder elektrisch) für einen sicheren Transport und III) der Optimierung der Wertschöpfungskette des Gesamtsystems „Batterie“ durch effizientere Batteriekreisläufe und Recyclingverfahren. T2 - Zweite Fachkonferenz Transport und Lagerung von Lithiumbatterien 2025 CY - Augsburg, Germany DA - 03.07.2025 KW - Batteriesicherheit KW - Gekühlter Transport von Batterien KW - Tieftemperaturpassivierung KW - Regelwerksentwicklung KW - Wertschöpfungskette und Batterierecycling PY - 2025 AN - OPUS4-65078 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Böttcher, Nils T1 - „Batterien“ Gefahrgutrechtliche Entwicklung für die Anwendung N2 - Der Markt für Energiespeicher bietet eine kontinuierlich wachsende, technologische Vielfalt. Neben etablierten Lithium-Ionen-Batterien gewinnen alternative Systeme wie Natrium-Ionen-Batterien zunehmend an Bedeutung. Jene Entwicklung steigert aktuell die Anforderungen an Regularien für Logistik und Handhabung ebendieser Systeme und bedarf einer dedizierten jedoch gleichwohl praktikablem Klassifizierung unterschiedlicher Batterien nach deren Gefährlichkeit. Genau dies ist der Schwerpunkt der vorliegenden Präsentation. Ein besonderer Fokus liegt dabei auf dem sicheren Transport kritisch defekter Batteriesysteme durch thermische Passivierung und/oder gezieltes Tiefentladen. Explizit werden aktuelle und zukünftige Batterietechnologien vorgestellt, die wesentlichen Herausforderungen bei Handhabung, Transport und Lagerung zusammengefasst und ein umfassender Ausblick auf die Weiterentwicklung der relevanten Regelwerke gegeben. T2 - 35. Münchner Gefahrgut-Tage CY - Munich, Germany DA - 26.05.2025 KW - Batteriesicherheit KW - Thermisches Durchgehen KW - Tieftemperaturpassivierung KW - Initiale Reaktionstemperatur KW - Gekühlter Transport von (kritisch) defekten Batterien PY - 2025 AN - OPUS4-65077 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Morcillo, Dalia T1 - High-resolution absorption isotopic spectrometry as a tool for aging studies of Li-ion batteries N2 - Lithium (Li) is the key element in the manufacturing of batteries. Isotopic study of Li may help to identify the causes of battery aging due to isotopic fractionation during charge/discharge cycles. Isotopic ratio determination is based on monitoring the isotopic components of lithium by their spin-orbit coupling and its isotopic shift of about 15 pm for the 22P←22S electronic transition around 670.788 nm. In this work, we propose improvements to our previous work [1] by using a higher-resolution double echelle modular spectrometer (HR-DEMON II) coupled to a continuum source graphite furnace atomic absorption spectrometer (HR-CS-GF-AAS) for the isotopic analysis of Li. The data analysis was carried out by using a decision-tree-based ensemble machine learning (ML) algorithm (XGBoost). A set of samples with 6Li isotope amount fractions ranging from 0.0004 to 0.99 mol mol-1 was used for the algorithm's training. Subsequently, the procedure was validated by a set of stock chemicals (Li2CO3, LiNO3, LiCl, and LiOH) and a BAM candidate reference material, a cathode material (NMC111). Finally, the ML model was applied to determine the isotope ratio of geological samples, including anorthosite, granite, soil, rhyolite, nepheline syenite, and basalt and battery samples. These samples were measured as digested without any further purification step. Improvements in the optical resolution resolve the lithium isotopic components of the atomic spectra. In the studied geological samples, were found δ7Li values between -0.5 and 4.5 ‰ with a precision range of 1 to 2 ‰. In addition, the proposed method was validated with multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), and these results are comparable and compatible. T2 - Caltech-BAM Meeting CY - Online meeting DA - 10.08.2022 KW - Lithium isotope KW - Machine learning KW - Battery KW - High-resolution absorption isotopic spectrometry PY - 2022 AN - OPUS4-56380 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Winckelmann, Alexander T1 - Investigation of degradation of the aluminum current collector in lithium-ion batteries by glow-discharge optical emission spectroscopy N2 - Lithium-ion batteries (LIBs) are one technology to overcome the challenges of climate and energy crisis. They are widely used in electric vehicles, consumer electronics, or as storage for renewable energy sources. However, despite innovations in batteries' components like cathode and anode materials, separators, and electrolytes, the aging mechanism related to metallic aluminum current collector degradation causes a significant drop in their performance and prevents the durable use of LIBs.[1] Glow-discharge optical emission spectroscopy (GD-OES) is a powerful method for depth-profiling of batteries' electrode materials. This work investigates aging-induced aluminum deposition on commercial lithium cobalt oxide (LCO) batteries' cathodes. The results illustrate the depth-resolved elemental distribution from the cathode surface to the current collector. An accumulation of aluminum is found on the cathode surface by GD-OES, consistent with results from energy-dispersive X-ray spectroscopy (EDX) combined with focused ion beam (FIB) cutting. In comparison to FIB-EDX, GD-OES allows a fast and manageable depth-profiling. Results from different positions on an aged cathode indicate an inhomogeneous aluminum film growth on the surface. The conclusions from these experiments can lead to a better understanding of the degradation of the aluminum current collector, thus leading to higher lifetimes of LIBs. T2 - European Winter Conference on Plasma Spectrochemistry (EWCPS 2023) CY - Ljubljana, Slovenia DA - 29.01.2023 KW - Lithium-ion batteries KW - Aging mechanisms KW - Depth-profiling PY - 2023 AN - OPUS4-56992 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Winckelmann, Alexander T1 - Investigation of degradation of the aluminum current collector in lithium-ion batteries by GD-OES N2 - Lithium-ion batteries (LIBs) are one technology to overcome the challenges of climate and energy crisis. They are widely used in electric vehicles, consumer electronics, or as storage for renewable energy sources. However, despite innovations in batteries' components like cathode and anode materials, separators, and electrolytes, the aging mechanism related to metallic aluminum current collector degradation causes a significant drop in their performance and prevents the durable use of LIBs. Glow-discharge optical emission spectroscopy (GD-OES) is a powerful method for depth-profiling of batteries' electrode materials. This work investigates aging-induced aluminum deposition on commercial lithium cobalt oxide (LCO) batteries' cathodes. The results illustrate the depth-resolved elemental distribution from the cathode surface to the current collector. An accumulation of aluminum is found on the cathode surface by GD-OES, consistent with results from energy-dispersive X-ray spectroscopy (EDX) combined with focused ion beam (FIB) cutting. In comparison to FIB-EDX, GD-OES allows a fast and manageable depth-profiling. Results from different positions on an aged cathode indicate an inhomogeneous aluminum film growth on the surface. The conclusions from these experiments can lead to a better understanding of the degradation of the aluminum current collector, thus leading to higher lifetimes of LIBs. T2 - Empa Group Meeting CY - Dübendorf, Switzerland DA - 22.11.2022 KW - Lithium Ion Batteries KW - GD-OES KW - FIB KW - SEM KW - EDX PY - 2022 AN - OPUS4-56584 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Böttcher, Nils T1 - A Journey From Formula Student to Research at BAM N2 - In this presentation, the battery and cell test center of BAM is introduced to the Berlin Motion Lab. Points of intersection are identified, and interested students are familiarized with BAM’s research priorities in the field of batteries. The aim is to foster interaction and to inspire young researchers to engage with technologically relevant topics. T2 - Berlin Deep Tech Nexus Meetup CY - Berlin, Germany DA - 26.02.2025 KW - Battery safety KW - BAM-academy KW - Qualification programme for PhD students at BAM KW - Advanced (battery) safety topics PY - 2025 AN - OPUS4-65079 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Long, Lijia A1 - Anh Mai, Q. A1 - Morato, P. G. A1 - Dalsgaard Sorensen, J. A1 - Thöns, Sebastian T1 - Information value-based optimization of structural and environmental monitoring for offshore wind turbines support structures N2 - The use of load and structural performance measurement information is vital for efficient structural integrity management and for the cost of energy production with Offshore Wind Turbines (OWTs). OWTs are dynamically sensitive structures subject to an interaction with a control unit exposed to repeated cyclic wind and wave loads causing deterioration and fatigue. This study focuses on the quantification of the value of structural and environmental information on the integrity management of OWT structures, with the focus on fatigue of welded joints. By utilizing decision analysis, structural reliability methods, measurement data, as well as the cost-benefit models, a Value of Information (VoI) analysis can be performed to quantify the most beneficial measurement strategy. The VoI assessment is demonstrated for the integrity management of a butt welded joint of a monopile support structure for a 3 MW OWT with a hub height of approximately 71m. The conditional value of three-year measured oceanographic information and one-year strain monitoring information is quantified posteriori in conjunction with an inspection and repair planning. This paper provides insights on how much benefits can be achieved through structural and environmental information, with practical relevance on reliability-based maintenance of OWT structures. KW - Structural health monitoring KW - Offshore wind turbine KW - Monopile support structure KW - Value of information KW - Weld fatigue KW - Decision tree KW - Dynamic Bayesian Network PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514098 DO - https://doi.org/10.1016/j.renene.2020.06.038 VL - 10 IS - 159 SP - 1036 EP - 1046 PB - Elsevier Ltd. AN - OPUS4-51409 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thöns, Sebastian A1 - Faber, M. H. A1 - Rücker, Werner T1 - Fatigue and serviceability limit state model basis for assessment of offshore wind energy converters N2 - This paper develops the models for the structural performance of the loading and probabilistic characterization for the fatigue and the serviceability limit states for the support structure of offshore wind energy converters. These models and a sensitivity study are part of a risk based assessment and monitoring framework and will be applied for establishing the 'as designed and constructed' reliability as prior information for the assessment and the design of monitoring systems. The constitutive physical equations are introduced in combination with the fatigue and serviceability limit state requirements as the starting point for the development of the structural performance and loading models. With these models introduced in detail, several modeling aspects for both limit states are analyzed. This includes analyses of the influence on the hot spot stresses by applying a contact formulation for the pile guide brace connection and the application of a finite element formulation using solid elements. Further, the comparison of the natural frequencies of a discrete rotor model with a continuous rotor model is documented. To account for uncertainties associated with the structural and loading models, a probabilistic model is derived on the basis of literature review and measurement data from a prototype Multibrid M5000 support structure. The sensitivity study is based on the calculation of a nonlinear coefficient of correlation in conjunction with predetermined designs of experiments. This is conducted by a systematic analysis of the influence of the random variables on limit state responses and hence on the structural reliability. Integrating the analyses and sensitivity studies of the fatigue and serviceability limit state models developed in this paper as well as the ultimate limit state models in Thöns et al. ('Ultimate Limit State Model Basis for Assessment of Offshore Wind Energy Converters,' ASME J. Offshore Mech. Arct. Eng.), the model basis for the assessment is completed. The process of establishing and analyzing such a model basis contributes to a detailed understanding of the deterministic and probabilistic characteristics of the structure and provides valuable insights in regard to the significance of available data. KW - Fatigue KW - Finite element analysis KW - Rotors KW - Wind power KW - Model basis KW - Offshore wind KW - Support structure KW - Sensitivity KW - Serviceability PY - 2012 DO - https://doi.org/10.1115/1.4004514 SN - 0892-7219 VL - 134 IS - 3 SP - 1 EP - 10 PB - American Society of Mechanical Engineers (ASME) CY - New York, NY AN - OPUS4-26437 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kunkel, Benny A1 - Seeburg, Dominik A1 - Kabelitz, Anke A1 - Witte, Steffen A1 - Gutmann, Torsten A1 - Breitzke, Hergen A1 - Buntkowsky, Gerd A1 - de Oliveira Guilherme Buzanich, Ana A1 - Wohlrab, Sebastian T1 - Highly productive V/Zn-SiO2 catalysts for the selective oxidation of methane N2 - The production of formaldehyde on industrial scale requires huge amounts of energy due to the involvement of reforming processes in combination with the demand in the megaton scale. Hence, a direct route for the transformation of (bio)methane to formaldehyde would decrease costs and puts less pressure on the environment. Herein, we report on the use of zinc modified silicas as possible support materials for vanadium catalysts and the resulting consequences for the performance in the selective oxidation of methane to formaldehyde. After optimization of the Zn content and reaction conditions, a remarkably high space-time yield of 12.4 kgCH2O⋅kgcat − 1 ⋅h− 1 was achieved. As a result of the extensive characterization by means of UV–vis, Raman, XANES and NMR spectroscopy it was found that vanadium is in the vicinity of highly dispersed zinc atoms which promote the formation of active vanadium species as supposed by theoretical calculations. This work presents a further step of catalyst development towards direct industrial methane conversion which may help to overcome current limitations in the future. KW - Catalysis KW - XANES KW - Selective oxidation PY - 2024 DO - https://doi.org/10.1016/j.cattod.2024.114643 SN - 0920-5861 VL - 432 SP - 1 EP - 13 PB - Elsevier B.V. AN - OPUS4-60137 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine T1 - Tribologische Untersuchungen unter GH2 und LH2-Bedingungen N2 - In diesem Beitrag werden Untersuchungen an Polymerwerkstoffen auf ihre Eignung für Reibsysteme in gasförmigem und flüssigem Wasserstoff vorgestellt. Dabei wird der Einfluss der Wasserstoffumgebung in Bezug auf die Materialzusammensetzung diskutiert. Weiterhin zeigen die Experimente in LH2 einen deutlichen Einfluss der Temperatur, der jedoch bei den verschiedenen Polymerverbundwerkstoffen unterschiedlich stark ausgeprägt ist. T2 - DKV Tagung CY - Hannover, Germany DA - 23.11.2023 KW - Polymerwerkstoffe KW - Reibung KW - Verschleiß KW - Gasförmiger Wasserstoff KW - Flüssiger Wasserstoff PY - 2023 AN - OPUS4-61963 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine T1 - Toward sustainable and hydrogen compatible sealing materials N2 - Materialien auf PTFE-Basis werden in der Regel als Kolbenringe in Hochdruck- und/oder kryogenem Wasserstoff verwendet. In diesem Projekt werden neu formulierte und nachhaltigere Polymerwerkstoffe mit herkömmlichen Materialien verglichen. Auf Grundlage der tribologischen Ergebnisse werden vielversprechende Kandidaten zusammen mit Reibungsmechanismen sowohl bei Hochdruck- als auch bei Niedrigtemperatur-Wasserstoff vorgeschlagen. T2 - 66. Tribologie-Fachtagung 2025 CY - Wernigerode, Germany DA - 29.09.2025 KW - Wasserstoff KW - Reibung KW - Verschleiß KW - Kolbenring KW - Dynamische Dichtung PY - 2025 AN - OPUS4-64313 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine T1 - Fretting wear of elastomer materials in hydrogen N2 - This paper presents an experimental study on the fretting wear behavior of two types of cross-linked hydrogenated acrylonitrile butadiene rubbers against 316L steel ball in hydrogen environment. Furthermore, aging experiments were conducted for 7 days under static conditions in 100 MPa hydrogen. The influences of hydrogen pressure as well as the aging exposure on the fretting behavior are discussed by means of surface analyses and well as material properties. T2 - WHEC-2022, 23rd World Hydrogen Energy Conference CY - Istanbul, Turkey DA - 26.06.2022 KW - Rubbers KW - Hydrogen KW - Fretting PY - 2022 AN - OPUS4-62086 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine T1 - Polymer tribology in cryogenic hydrogen N2 - In this presentation, an overview of polymer tribology in cryogenic hydrogen is given along comparison with other environments. T2 - Hydrogenius Symposium 2024 CY - Kyushu University Ito Campus, Japan DA - 12.09.2024 KW - Hydrogen KW - Friction KW - Wear KW - Polymer materials KW - Cryogenic PY - 2024 AN - OPUS4-61426 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. A1 - Hajhariri, Aliasghar A1 - Sklorz, Christian A1 - Kriegsmann, Andreas A1 - Müller, Karsten T1 - A modular concept for protection against debris flight - Design, properties and usage N2 - With advances in technological development, stationary and mobile storage units for compressed hydrogen are becoming larger and larger. Their number is also increasing. At the same time, their design has evolved from steel and aluminium to pressure vessels made of composite materials. For safety reasons the design approval of those composite cylinders requires fire engulfment tests, which are mainly organised as open-air tests always needs dedicated protection measures. Under some conditions those protections measures even reduce the effort for organisational safety measures if e.g. the emission of splinters can get totally prevented. Another aspect is the improved reproducibility of fire tests by reducing the influence of wind. Between 2017 and 2019, BAM developed a stackable protective frame made of steel to safely capture splinters for the safe execution of high-energy impact tests. However, this frame was not flexible enough for the follow-up project, which led to a completely new protection concept for (potentially) destructive tests on gas-filled pressure vessels. This concept is based on very robust building blocks made from welded steel. Despite their considerable weight of around 500 kg p.p., they can be combined and stacked very easily like ‘Lego bricks’. The presentation will show the flexibility of the concept, some results of tests on the robustness against pressure waves and the effectiveness in wind attenuation. Finally, the interaction with a new, also modular burner concept for localised fires and full engulfment fires will be presented. T2 - 11th International conference on hydrogen safety (ICHS 2025) CY - Seoul, Republic of Korea DA - 22.09.2025 KW - Splinter protection KW - Pressure vessel testing KW - Fire engulfment KW - Destructive tests KW - Rupture KW - Gaseous tests KW - Pressure wave KW - Test equipment KW - Precaution measures PY - 2025 SN - 979-1-2243-0274-2 VL - 2025 SP - 1428 EP - 1439 AN - OPUS4-65100 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. T1 - Welcome to BAM and the Competence Centre H2Safety@BAM N2 - The presentation starts with general slides on BAM, its mission and focus areas. It provides the fields of activity in the focus area “Energy” and explains the structure of the competence Centre and its focus on building trust in hydrogen. The next part shows the H2Safety@BAM’s Products“ in a nutshell and explains the main items with deep dives on the Living Lab “Hydrogen Networks”, the Living Lab „Hydrogen Refuelling Station“, on Reference Materials and Procedures, Storage of Liquid Hydrogen, Storage Systems for Compressed Gases and Material Compatibility. T2 - Information Tour at the Invitation of the Federal Foreign Office The Hydrogen Economy in Germany CY - Berlin, Germany DA - 05.11.2025 KW - Living Lab “Hydrogen Networks” KW - Living Lab „Hydrogen Refueling Station“ KW - Reference Materials and Procedures KW - Storage of Liquid Hydrogen KW - Storage Systems for Compressed Gases KW - Material Compatibility PY - 2025 AN - OPUS4-65101 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sterr, Andrea A1 - Schwarz, Irina T1 - Valorization of Carbon Dioxide by Electrocatalytic Reduction Coupled to Acetogens via Multiple Electron Carriers (Ecat-Acetogens II) N2 - A Bioelectrochemical approach for reducing CO2 to fuels or value-added chemicals allows overcoming the limitations of a pure biochemical or electrochemical approach. A Bioelectrochemical system (BES) for this application has been developed in cooperation with TUM in the first project phase. BAM's contribution to the research focuses on the electrochemical side of the setup, mainly on the development of a suitable CO2RR catalyst for reducing CO2 to CO, which is then consumed by actogenic bacteria to produce further products. Single-metal-atom catalysts in a nitrogen-doped carbon matrix (M-N-Cs) are a promising, sustainable alternative to expensive rare-metal catalysts like Ag and Au. In this work, the first-generation catalyst, a ZIF-8-based Co-N-C is compared to a Mg salt mix templated Ni-N-C. In the new catalysts, the activity for CO2RR as well as the stability during BES operation could be enhanced. T2 - E-Biocat Statusupdate 2025 CY - Karlsruhe, Germany DA - 01.04.2025 KW - CO2RR KW - M-N-Cs KW - Bioelectrochemical System PY - 2025 AN - OPUS4-65143 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. T1 - DE-JP Hydrogen Safety Cooperation - Contribution of H2Safety@BAM N2 - The presentation starts with general slides on BAM, its location, mission, tasks and focus areas. It provides the fields of activity in the focus area “Energy” and explains the structure of the competence Centre and its focus on building trust in hydrogen. The test sides at TTS on hydrogen are explained in combination with the H2Safety@BAM’s products in a nutshell. Then the major H2-applications of H2Safety@BAM are explained by deep dives on the Living Lab “Hydrogen Networks”, the Living Lab „Hydrogen Refuelling Station“, on Explosion Protection, on Reference Materials and Procedures, on Material Compatibility, on Storage Systems for Compressed Gases and Storage of Liquid Hydrogen as well as on the Training and Further Education. The presentation ends with an overview about our international work on H2Safe-Collaboration. T2 - KICK-OFF WORKSHOP: JAPANESE-GERMAN COOPERATION ON H2 SAFETY CY - Online meeting DA - 15.12.2025 KW - Living Lab KW - Hydrogen Networks KW - Hydrogen Refuelling Station KW - Explosion Protection KW - Material Compatibility KW - Liquid Hydrogen KW - Compressed Gases PY - 2025 AN - OPUS4-65151 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scharf-Wildenhain, R. T1 - Influence of build up height on residual stresses in additive repair and modification using DED Arc N2 - Directed Energy Deposition (DED)-Arc is suitable for the hybrid additive manufacturing, modification and repair of large metal components with high deposition rates. Residual stresses and distortion are of central importance when characterizing the manufactured components and the sensitive transition area between AM component and semi-finished product. Residual stresses caused by the thermal cycles during the manufacturing process can impair the mechanical properties of the manufactured parts and can lead component failure. Therefore, understanding and controlling residual stresses, especially when combining different base and filler materials, is critical to improving the quality and efficiency of the hybrid DED-Arc process. This article deals with the influence of the build-up height on the residual stress distribution of additively manufactured components with a selected base and filler material combination. Using a robot-assisted DEDsystem and a controlled short arc, systematic step cancellation tests were carried out at a selected working temperature (200 C°) and heat input (600 kJ/m). In a 5-stage termination experiment, straight walls were produced using a one bead per layer strategy and selected increasing component heights between 15 mm and 300 mm. The influence of the build height on the longitudinal residual stress in the process direction was analyzed and discussed. All experiments showed a comparable stress distribution in the area of the substrate plate up to the heat-affected zone (HAZ) and the transition zone, regardless of the buliding height. However, the height showed a significant influence on the of residual stress distribution of the deposited AM-component. High positive stress gradients with a maximum range between 300 MPa to 400 MPa were always found in the last approx. 18 component layers (upper 40 mm), which can be explained by the shrinkage of the nonheat- treated top layer. Underlying layers, where present, showed a homogeneous residual stress distribution characterized by low compressive stresses. This can be explained by the process related tempering during the deposition of the upper layers. A constant boundary layer number was determined for all specimens. Once this number was exceeded, the distribution of residual stresses no longer changed, but merely shifted with the increasing height of the component in the direction of build-up. These correlations contribute to the understanding of residual stress development with increasing structure height. This study is part of a running research project on the properties of hybrid additive components and processes. It aims the stress optimized hybrid additive manufacturing of high-strength components and the necessary recommendations for application. T2 - 78th IIW Annual Assembly and International Conference on Welding and Joining CY - Genoa, Italy DA - 22.06.2025 KW - DED-Arc KW - Additive manufacturing KW - Residual stress PY - 2025 AN - OPUS4-65192 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ghaznavi, Ali T1 - Machine Learning Approach for Robust Acoustic Emission-Based Damage Classification in Pressure Vessels N2 - Accurate damage classification of Composite Pressure Vessels (CPVs) is crucial for understanding failure behaviour of hydrogen storage systems. Acoustic Emission (AE) monitoring is a non-destructive testing technique capable of detecting signals from different failure mechanisms such as fiber breakage and matrix cracking, supporting durability assessment of CPVs. Therefore, the main objective of this study is to combine AE and advanced deep learning techniques to develop a robust framework for automatic and accurate identification and classification of damage mechanisms across various CPVs. The evolutionary Genetic Algorithms (GA) was used for feature selection, followed by unsupervised clustering to generate automatic labels for model training. Two different FCNN and CNN-LSTM architectures were used to train individual models based on different AE datasets. Later, Adaptive Transfer Learning (ATL) and Meta Ensemble Learning (MEL) techniques were applied to handle data variability and train predictive generalized model over varied AE datasets. The ATL fine-tunes a pre-trained models to leverage their knowledge, while MEL uses pre-trained models' predictions as meta features to train a meta model. Experimental results demonstrate that while both generalized ATL and MEL trained models perform well across different AE datasets, the MEL framework outperforms ATL method in terms of evaluation metrics. The Mean-Accuracy score reaches 0.9026, and 0.9900 for ATL, and MEL, respectively. The most accurate multi-class classification results was achieved using MEL method in terms of the Mean-Accuracy and Recall metrics. The proposed framework provides a scalable, adaptive approach for automated damage classification using AE signals across diverse CPVs in real-world settings. T2 - BAM Colloquium Abteilung 3 CY - Berlin, Germany DA - 14.10.2025 KW - Acoustic Emission KW - Machine Learning KW - Sequential Neural Network KW - Deep Learning KW - Deep Neural Network PY - 2025 AN - OPUS4-65184 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröpfer, Dirk T1 - Wear resistance of modified Ni based claddings in relation to the resulting machinability via ultrasonic-assisted milling N2 - In the field of plastics processing, extruder screws are subjected to significant wear stresses. The extruder screw is the main wear component in those production machines and is usually coated with intermetallic wear protection alloys composed of Ni-based alloys, specifically Colmonoy C56 PTA (NiMoCrSi). There is a growing demand for providing an economic machinability of these alloys to achieve defined contours with a sufficient surface integrity. Recent investigations exhibit promising results applying ultrasonic milling for such hard-to-cut materials. The Colmonoy C56 is modified by various alloying additions Ti, Nb, Mo, Hf, and Al, and then cladded on a steel S355 via Plasma Transferred Arc process. The effect of alloying additions on the microstructure is analyzed regarding their resistance to abrasive and adhesive wear. With Miller test ASTM G75 the influence of alloying elements on resistance to abrasive wear for two abrasive materials is investigated (high-grade corundum F220 and quartz powder). The wear loss is not increased for additions of Nb and Ti compared to the base material C56. Modifications with Hf or Al reduces the resistance to abrasive wear and significantly increases material loss. The extruder screw is also subject to adhesive wear, which can be quantified by means of the pin-roll test. It is demonstrated that the addition of Hf, for example, contributes to a reduction in wear loss. Aim of the investigations is to find suitable modifications for the wear claddings of C56 for a sufficient machineability, without compemising the wear resistant. The machinability is considerably affected by the alloy additions, and is determined using ultrasonic-assisted milling. The addition of hafnium reduces machinability, i.e. significantly increases cutting forces. The incorporation of Nb exhibits a significant reduction of cutting forces, and results in reduced tool wear and an enhanced of surface integrity (roughness, density of defects, residual stresses). T2 - Wear of Materials 2025 CY - Sitges, Spain DA - 13.04.2025 KW - Abrasive wear KW - Adhesive wear KW - Colmonoy C56 KW - PTA welding KW - Service life and efficiency KW - Substitution of critical raw materials KW - Surface integrity KW - Ultrasonic-assisted milling process PY - 2025 AN - OPUS4-65189 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Drexler, A.-K. A1 - Konert, Florian A1 - Nietzke, Jonathan A1 - Hodžić, E. A1 - Pastore, S. A1 - Domitner, J. A1 - Rhode, Michael A1 - Sommitsch, C. A1 - Böllinghaus, Thomas T1 - Effect of Tensile Loading and Temperature on the Hydrogen Solubility of Steels at High Gas Pressure N2 - The hydrogen solubility in ferritic and martensitic steels is affected by hydrostatic stress, pressure, and temperature. In general, compressive stresses decrease but tensile stresses increase the hydrogen solubility. This important aspect must be considered when qualifying materials for high‐pressure hydrogen applications (e.g., for pipelines or tanks) by using autoclave systems. In this work, a pressure equivalent for compensating the effect of compressive stresses on the hydrogen solubility inside of closed autoclaves is proposed to achieve solubilities that are equivalent to those in pipelines and tanks subjected to tensile stresses. Moreover, it is shown that the temperature effect becomes critical at low temperatures (e.g., under cryogenic conditions for storing liquid hydrogen). Trapping of hydrogen in the microstructure can increase the hydrogen solubility with decreasing temperature, having a solubility minimum at about room temperature. To demonstrate this effect, the generalized law of the hydrogen solubility is parameterized for different steels using measured contents of gaseous hydrogen. The constant parameter sets are verified and critically discussed with respect to the high‐pressure hydrogen experiments. KW - Hydrogen KW - Solubility KW - Temperature KW - Tensile loading KW - Analytical calculation PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586701 DO - https://doi.org/10.1002/srin.202300493 SN - 1611-3683 SP - 1 EP - 9 PB - Wiley AN - OPUS4-58670 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Sobol, Oded T1 - Hydrogen assisted cracking and transport studied by ToF-SIMS and data fusion with HR-SEM N2 - For almost 150 years it is known that hydrogen has a deleterious effect on the mechanical properties of metallic components. Nowadays, the problem of hydrogen assisted degradation is highly relevant in energy related fields due to the massive use of steel as a structural component in these applications and its sensitivity to hydrogen. Since the discovery of hydrogen assisted cracking (HAC), researchers studied intensively and suggested possible explanations and mechanisms in order to define how hydrogen is affecting the material. In general, it is considered that hydrogen changes the mechanical properties more in terms of ductility (deformation capacities) than in strength (load capacities). Hydrogen concentration is one of three crucial factors in the degradation process, together with the microstructure of the material and the internal/external mechanical load. The relatively high concentration of hydrogen resulting in this loss of ductility can originate during production or before service (e.g. welding processes) and during service (i.e. catholically protected systems to eliminate corrosion processes in sour environments). In parallel to the theoretical work, tremendous efforts were, and are still, invested in searching for a proper method to elucidate, map and quantify the hydrogen in the microstructure, which is the basis for this work. For steels, the focus is mainly on the observations of diffusion processes and the interaction of hydrogen with the microstructure in regions with high local stresses/strains (for example around evolving cracks). The challenge for reaching this goal arises from the fact that accurate indication of hydrogen by means of position, unlike heavier atoms, can be made only by mass spectrometry or by interaction with another element (e.g. silver decoration, special coating and resonant nuclear reaction by nitrogen). In addition to this, the difficulty recording the hydrogen behavior while it rapidly diffuses through the material, leaving only the unpredicted failure, should be taken into account. Although using powerful characterization methods, models and computational simulations, the key to defining the mechanisms behind HAC is still under debate and not fully understood. The relationship between material and hydrogen is determined by three factors, i.e., the material structure and microstructure – determining the physical properties, the mechanical load applied on the material and the hydrogen concentration. It is well known that in order to have a complete definition of HAC these three factors must be examined locally with the minimal scale and the maximal resolution reachable. The major gap is the lack in such a characterization method or a technique by which one has the ability to detect and observe the hydrogen in the metallic microstructure. The commonly used techniques nowadays are capable of characterization of the microstructure without the ability to observe the hydrogen distribution. Global hydrogen concentration and localized hydrogen observation are possible by some techniques which are incapable of indicating a change in the structure or microstructure therefore a comprehensive overview can be gained only by combining several methods. In the presented research, secondary ion mass spectrometry (SIMS) was adopted as the main tool to detect and locally map the hydrogen distribution in two types of duplex stainless steel grades: EN 1.4462 (standard 2205 duplex stainless steel) and EN 1.4162 (2101 lean duplex stainless steel). The term duplex stainless steel (DSS) refers to the austenitic-ferritic microstructure of the steel where the combination of physical and mechanical properties of the two phases is achieved. The DSS was selected as a case study for this work due to the wide use of this grade in many energy and the lack of knowledge on hydrogen behavior in two-phase containing microstructures. ToFSIMS was exploited in-situ and ex-situ in three experimental approaches during or following an electrochemical charging procedure. This type of hydrogen charging was selected as it simulated a procedure of cathodic protection of most sub-water oil and gas extraction and delivery systems. The experimental procedures were: 1. Ex-situ charging followed by ToF-SIMS imaging for basic understanding of hydrogen distribution. 2. Ex-situ charging followed by in-situ mechanical loading to obtain information on hydrogen behavior around a propagating crack. 3. In-situ permeation of hydrogen through a steel membrane inside the ToF-SIMS to obtain information on diffusion behavior of hydrogen in a two-phase microstructure. The comprehensive view of the effect of hydrogen on steel was gained by using supplementary methods, such as high resolution scanning electron microscopy (HR-SEM), focused ion beam (FIB) and electron back-scattered diffraction (EBSD). The state of the art in this work lies in applying both: in-situ experimental approaches and data treatment of the ToF-SIMS raw data. The data treatment includes the combination of data from several sources (data fusion). The results for the ex-situ charging followed by static sample imaging and data fusion showed that when the analyzed surface is directly exposed to the electrolyte the degradation is pronounced differently in the ferrite, austenite and interface. The degradation mechanisms in the ferrite and austenite were reflected by the formation of cracks on the surface of both, where a high concentration of hydrogen was obtained. This result supports the assumption that hydrogen is attracted to highly deformed regions. The advantage of using in-situ charging/permeation in comparison to ex-situ charging is that the effect of hydrogen on the ferrite and austenite phases when the hydrogen is evolving from within the microstructure is realized, in comparison to when the analyzed surface is initially exposed directly to the electrolyte. In both experiments the ferrite was observed as a fast diffusion path for the hydrogen. The faster diffusion of hydrogen through the ferrite is expected due to the higher diffusion coefficient, however, a direct proof for the diffusion sequence in this scale was never shown. Most significant results were achieved by the ‘core’ experiments of this research. These experiments included the design of a novel dynamic mechanical loading device to apply an external load during SIMS imaging of a hydrogen precharged-notched sample. For the first time it was shown that plastic deformation induced by applying a mechanical load is resulting in a redistribution of hydrogen locally around the notch. T3 - BAM Dissertationsreihe - 160 KW - Duplex stainless steels KW - Hydrogen assisted cracking KW - Time-of-Flight secondary ion mass spectrometry KW - Data fusion PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-447331 SN - 1613-4249 VL - 160 SP - I EP - 180 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-44733 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Drexler, A A1 - Konert, Florian A1 - Sobol, Oded A1 - Rhode, Michael A1 - Domitner, J A1 - Sommitsch, C A1 - Böllinghaus, Thomas T1 - Enhanced gaseous hydrogen solubility in ferritic and martensitic steels at low temperatures N2 - Metals that are exposed to high pressure hydrogen gas may undergo detrimental failure by embrittlement. Understanding the mechanisms and driving forces of hydrogen absorption on the surface of metals is crucial for avoiding hydrogen embrittlement. In this study, the effect of stress-enhanced gaseous hydrogen uptake in bulk metals is investigated in detail. For that purpose, a generalized form of Sievert's law is derived from thermodynamic potentials considering the effect of microstructural trapping sites and multiaxial stresses. This new equation is parametrized and verified using experimental data for carbon steels, which were charged under gaseous hydrogen atmosphere at pressures up to 1000 bar. The role of microstructural trapping sites on the parameter identification is critically discussed. KW - Hydrogen KW - Thermodynamic modelling KW - Pressure-dependent solubility KW - Steel KW - Trapping PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559307 DO - https://doi.org/10.1016/j.ijhydene.2022.09.109 SN - 0360-3199 VL - 47 IS - 93 SP - 39639 EP - 39653 PB - Elsevier Ltd. AN - OPUS4-55930 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Campari, Alessandro A1 - Konert, Florian A1 - Sobol, Oded A1 - Alvaro, Antonio T1 - A comparison of vintage and modern X65 pipeline steel using hollow specimen technique for in-situ hydrogen testing N2 - The transition toward a hydrogen-based economy requires a widespread transport and distribution network, and repurposed natural gas pipelines are a viable option. An assessment of the hydrogen-induced degradation of pipeline steels is needed to inject H2 gas into the existing infrastructure safely. The conservative and standardized method consists of in-situ tensile tests in an autoclave filled with high-pressure hydrogen gas. A proposed alternative method involves using a hollow specimen as containment volume and applying the gas pressure in the inner cavity. This technique has lower costs and shorter test preparation time but is not standardized yet. This study aims to evaluate and compare the tensile properties of API 5L X65 pipeline steel in two states: vintage and modern. The influence of the surface roughness is investigated through parallel tests with drilled and reamed specimens. Hydrogen tests are compared with reference tests in an inert environment. A significant hydrogen-induced decrease in tensile properties is observed, and no significant difference between vintage and modern X65 can be drawn. The reduction in tensile properties is more significant in specimens with higher inner surface roughness. The evaluation of surface conditions appears crucial when assessing the HE susceptibility of hydrogen transport and storage equipment. KW - Hydrogen embrittlement KW - Hollow specimen technique KW - Pipeline steel KW - SSRT PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603013 DO - https://doi.org/10.1016/j.engfailanal.2024.108530 VL - 163 SP - 1 EP - 15 PB - Elsevier Ltd. AN - OPUS4-60301 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nietzke, Jonathan A1 - Konert, Florian A1 - Poka, Konstantin A1 - Merz, Benjamin A1 - Sobol, Oded A1 - Böllinghaus, Thomas T1 - Comparison of hydrogen effects on additively manufactured and conventional austenitic steels N2 - Hydrogen and its derivatives are promising energy carriers for future renewable energy supplies. Austenitic stainless steels, such as AISI 316L, are commonly used in hydrogen transportation systems. While often thought to be resistant to hydrogen embrittlement, studies have shown that 316L is susceptible under certain conditions. As demand for hydrogen applications grows, additive manufacturing (AM) technologies offer design flexibility and customisation benefits. However, data on AM parts behaviour in hydrogen environments is lacking. This study investigates the influence of hydrogen on mechanical properties using slow strain rate testing (SSRT) on conventional AISI 304L, 316L and AM 316L specimens. The results indicate a greater effect of hydrogen on 304L compared to 316L, with AM 316L showing increased susceptibility. However, the ductility of AM 316L remains comparable to conventional 316L due to its initial ductility. The study provides insights into the performance of conventional and AM austenitic stainless steels in gaseous hydrogen environments. KW - Slow strain rate testing KW - Hollow specimen KW - Hydrogen embrittlement KW - Additive manufacturing KW - Austenitic steel PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615919 DO - https://doi.org/10.1016/j.engfailanal.2024.109042 SN - 1350-6307 VL - 167 SP - 1 PB - Elsevier B.V. AN - OPUS4-61591 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grimault de Freitas, Tomás A1 - Konert, Florian A1 - Nietzke, Jonathan A1 - Krzysch, Zephanja A1 - Böllinghaus, Thomas A1 - Michler, Thorsten A1 - Wackermann, Ken A1 - Oesterlin, Heiner A1 - Tlili, Mohamed A1 - Ruchti, Peter A1 - Beitelschmidt, Denise A1 - Elsen-Humberg, Stephan A1 - Koenigs, Timo A1 - Systermans, Thomas A1 - Sobol, Oded T1 - Tensile testing in high-pressure gaseous hydrogen using the hollow specimen method N2 - Metallic materials, predominantly steels, are the most common structural materials in the various components along the hydrogen supply chain. Ensuring their sustainable and safe use in hydrogen technologies is a key factor in the ramp-up of the hydrogen economy. This requires extensive materials qualification, however, most of the accepted; and standardized test methods for determining the influence of gaseous hydrogen on metallic materials describe complex and costly procedures that are only available to a very limited extent worldwide. The hollow specimen technique is a simple, rapid, and economical method designed to overcome the limitations of the current methods for the qualification of metallic materials under high-pressure hydrogen gas. However, this technique is not yet standardized. The TransHyDE-H2Hohlzug project is presented in this article, along with the main steps required to optimize the hollow specimen technique. This includes closing knowledge gaps related to the specimen geometry, surface quality, and gas purity in dedicated working packages, thus contributing to a comprehensive standardization of the technique for tests in high-pressure hydrogen gas. KW - High-pressure Gaseous Hydrogen KW - Hydrogen Embrittlement KW - Tensile Testing KW - Hollow Specimen Technique PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610557 DO - https://doi.org/10.1557/s43577-024-00776-9 VL - 49 SP - 1 EP - 9 PB - Springer Nature AN - OPUS4-61055 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Konert, Florian A1 - Nietzke, Jonathan A1 - Grimault de Freitas, Tomás A1 - Rhode, Michael A1 - Sobol, Oded A1 - Böllinghaus, Thomas T1 - Investigation of resistance to gaseous hydrogen of a longitudinal weld seam in a X65 pipeline using the hollow specimen technique N2 - The constantly increasing demand for renewable energy sources leads to the necessity of transporting large amounts of hydrogen. Since pipelines enable a cost-effective way for the distribution of gaseous hydrogen, the interaction of hydrogen and the pipeline materials must be carefully investigated as hydrogen can cause a degradation of the mechanical properties under certain conditions. Especially welds, which are assumed to be more susceptible to the degradation enhanced by hydrogen, are of great interest. The aim of this study is to investigate the effect of gaseous hydrogen on the mechanical properties of an X65 pipeline, and the longitudinal submerged arc welding (SAW) welded joint. The tests are conducted using the hollow specimen technique on two types of specimens: one extracted from the base material (BM) and the other extracted as a cross-weld (CW) specimen consisting of BM and weld seam. The specimens are charged in situ under a pressure of 60 bar and tested using slow strain rate (SSR) tensile tests with a nominal strain rate of 10−5 s−1. The properties obtained of specimens tested in hydrogen atmosphere are compared to the properties of comparable specimen in inert argon atmosphere as a reference. The performed tests showed a decrease of the reduction of area (RA) from 72% in inert atmosphere to 52% in hydrogen atmosphere for the CW specimen and a decrease from 73% in inert atmosphere to 51% for the BM. Metallographic analyses showed the crack initiation between fine-grained heat-affected zone (FGHAZ) and BM for the specimens tested in hydrogen atmosphere as well as for the reference specimens. This leads to the conclusion that the location of the crack initiation does not change due to the presence of gaseous hydrogen. KW - Hydrogen KW - Hollow specimen technique KW - Pipeline KW - SSRT KW - Hydrogen embrittlement KW - Cross-weld specimen PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624658 DO - https://doi.org/10.1007/s40194-025-01953-3 SN - 0043-2288 SN - 1878-6669 VL - 69 IS - 3 SP - 861 EP - 870 PB - Springer CY - Berlin AN - OPUS4-62465 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Hydrogen in Welded Microstructures of T24 Steel: Effect on Mechanical Properties and Corresponding Hydrogen Diffusion N2 - Low-alloyed CrMoV steels, such as T24, are widely used for welded components in fossil power stations due to their excellent creep-strength. Spectacular failure cases in the recent years exhibited severe cracking in T24 welds. The results showed that hydrogen-assisted cracking (HAC) occurring up to 200 degree Celsius cannot be excluded. Hence, a basic understanding is necessary on how hydrogen affects the material properties of welded microstructures. In this regard, each weld microstructure (HAZ and weld metal) has influence on the HAC susceptibility and respective hydrogen diffusion. Thus, the present contribution summarizes different results obtained from experiments with grades T24 (CrMoV alloy) and T22 (CrMo) and thermally simulated HAZ. Tensile tests were conducted with hydrogen charged specimens and compared to hydrogen-assisted stress corrosion cracking results obtained from slow strain rate tests (SSRT) up to 200 degree Celsius. Electrochemical permeation and degassing experiments were performed to identify a particular weld microstructure influence on hydrogen diffusion and trapping (especially in the HAZ). The results showed that T24 base material has improved resistance to hydrogen-assisted degradation/cracking. In contrast, the as-welded HAZ had remarkably increased susceptibility (tesnile tests at hydrogen concentration of 1 to 2 ppm). SSRT experiments confirmed this at elevated temperatures for both the T24 and the T22. Hence, the evaluation of a particular degradation of the mechanical properties should be performed independently for each weld microstructure. In addition, the HAZ showed decreased diffusion coefficients (at room temperature) of approximately one magnitude compared to the base materials. Trapped hydrogen was determined in the T24 at temperatures up to 120 degree Celsius compared to 75 degree Celsius in the T22. This has to be considered in case of changing operational temperatures, e.g. in the case of start-up and shutdown processes of boiler components. T2 - 10th Conference on Trends in Welding Research CY - Tokyo, Japan DA - 11.10.2016 KW - Degradation of Mechanical Properties KW - Hydrogen KW - Creep-resistant Steel KW - Weld Joint KW - Diffusion PY - 2016 AN - OPUS4-37827 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grimault de Freitas, Tomás T1 - Hollow Specimen Method for Tests in High-Pressure Hydrogen Gas: The Role of Strain-Rate and Surface Quality N2 - The hollow specimen technique is a simple and economical technique that has the potential to make materials qualification with pressurised gaseous hydrogen widely accessible to academia and industry. This contribution focuses on the results obtained from assessing the influence of the specimen production and its response to hydrogen effects. Depending on the production method, different roughness and residual stresses can be expected on the inner hole surface of the specimens. This is relevant because an increase in stress concentration sites, e.g. notches, has been found to be associated with increased severity of hydrogen effects. The presence of strain-induced martensite caused by mechanical stress may also be detrimental and accelerate the embrittlement. To assess this influence, the inner hole of the hollow specimens was manufactured in two different ways: 1) only drilling; 2) EDM followed by honing. A representative steel widely used in hydrogen technologies was assessed, X5CrNi18-10 (AISI 304). Roughness measurements, and electron back-scatter diffraction (EBSD) analysis have been performed previous to mechanical testing to infer on the effect of the different production methods on the surface of the inner hole. Next, the specimens were mechanically tested via slow strain rate tensile tests in argon and in hydrogen, both at 150 bar and room temperature. Here, a strain-rate sensibility analysis was performed to investigate the influence of strain-rate on hydrogen degradation. T2 - International Conference on Hydrogen Safety 2025 CY - Seoul, South Korea DA - 22.09.2025 KW - Tensile Testing KW - Hollow Specimen Technique KW - High-Pressure Hydrogen Gas KW - Hydrogen Embrittlement KW - Surface Condition KW - Strain Rate PY - 2025 AN - OPUS4-64286 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grimault de Freitas, Tomás T1 - Hollow Specimen Method for Tests in High-Pressure Hydrogen Gas: The TransHyDE - H2HohlZug Project N2 - As the world moves towards a decarbonised economy, the demand for sustainable and low-carbon alternatives is growing rapidly. Hydrogen has an important role to play in this transition, but in order to make the most of hydrogen as an energy carrier, a comprehensive understanding of its impact on the integrity of structural materials is necessary. Metallic materials, mainly steels, are the most commonly used structural materials in various components throughout the hydrogen supply chain. Ensuring their sustainable and safe use in hydrogen technologies is a crucial factor in the development of the hydrogen economy. This is particularly important since hydrogen can promote crack formation and ultimately lead to premature failure in these materials when combined with mechanical load. This process is commonly known as Hydrogen Embrittlement and can occur in almost all the steels used for the hydrogen technologies. Extensive materials qualification is required for the rapid implementation of hydrogen technologies, however, most accepted, and standardised test methods for determining the effect of gaseous hydrogen on metallic materials describe complex and costly procedures that are only available to a very limited extent worldwide. The hollow specimen technique is a simple and economical method that has the potential to overcome the limitations of the current methods and complement them for qualifying metallic materials under high-pressure hydrogen gas. Unlike the conventional autoclave technique, this method requires significantly lower amounts of hydrogen, resulting in fewer safety measures and no need for complex equipment or a specialised laboratory. The technique's low investment and testing costs, simple operation, and shorter testing time make it an optimal for widespread use around the world, thereby increasing the output of results. Initial studies have demonstrated the feasibility of assessing hydrogen effects in metallic materials using the hollow specimen technique. This led to the establishment of an ISO committee to standardise the method. However, there are open questions that currently prevent the technique from being standardised for hydrogen testing. These open questions relate to specimen geometry, inner hole surface and gas quality and are being addressed in the H2HohlZug project, of which the overall aim is to systematically close the gaps towards a standard. This contribution presents the structure and milestones of the project, followed by initial results. T2 - TransHyDE Vollversammlung 2025 CY - Leipzig, Germany DA - 26.11.2025 KW - Hydrogen KW - Hydrogen Embrittlement KW - Hollow Specimen Technique KW - High-Pressure Gaseous Hydrogen KW - TransHyDE KW - H2HohlZug KW - Standardisation PY - 2025 AN - OPUS4-64938 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - El Harrab, Hayat A1 - Askar, Enis A1 - Franken, T. A1 - Mauss, F. T1 - Experimental and Kinetic Study of Lubrication Oil Composition on Hydrogen Auto-Ignition N2 - Hydrogen internal combustion engines (H₂ ICEs) present a promising alternative to conventional fuels, but they face challenges such as pre-ignition, where lubricating oils play a critical role. This study investigates the auto-ignition behavior of two base oils — Group II (mineral) and Group V (Ester) — and three formulated oils (Oils A, B, and C) at 20 bar using a heated constant-volume autoclave. Oil A and Oil B share a Group II (mineral) base, with Oil A containing lower levels of calcium-based detergents and higher levels of phosphorus-based antioxidants compared to Oil B. In contrast, Oil C is formulated with a Group V (ester) base oil, incorporating magnesium-calcium detergents. The auto-ignition temperature was measured in both air and stoichiometric hydrogen-air mixtures to assess the influence of oil composition, additives, and hydrogen addition on ignition characteristics. Results show that hydrogen’s AIT at 20 bar is 460°C but drops to 270°C with the addition of 0.2 ml of base oil. Base oils exhibited similar AITs in air (260°C) and hydrogen-air mixtures (270°C), with reactivity differences linked to molecular composition — ester (Group V) displayed lower reactivity compared to mineral oil (Group II). Formulated oils demonstrated slightly higher AITs (up to 290°C), where phosphorus-based additives reduced reactivity, while lower calcium content further slowed ignition. Among the tested oils, the ester-based oil with a mixture of calcium and magnesium detergents exhibited the lowest reactivity, making it a promising candidate for hydrogen engines. Additionally, reduced oxygen availability increased AIT by 10°C and prolonged ignition delay. A chemical analysis was also performed to evaluate the ignition properties of Group II (mineral) and Group V (ester) oils under varying temperatures. These findings highlight the impact of lubricant composition on pre-ignition behavior in H₂ ICEs, offering valuable insights for optimizing lubricant formulations. T2 - 12th European Combustion Meeting CY - Edinburgh, United Kingdom DA - 07.04.2025 KW - Hydrogen KW - Pre-Ignition KW - Group V Ester Oil KW - Auto-Ignition Temperature KW - Additive Effects KW - Ignition Delay Time KW - Group II Mineral Oil KW - Lubricating Oil PY - 2025 AN - OPUS4-64761 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fedelich, Bernard T1 - Constitutive modeling and lifetime prediction for a conventionally cast Ni-base superalloy under TMF loading N2 - Under cyclic thermomechanical loading, various effects such as strain accumulation, creep damage, ageing, fatigue etc. may occur in the material of a gas turbine blade. Depending on the loading conditions, all these effects contribute to reduce the lifetime of the component. Subject of the present work is the development of a material model to describe the mechanical effects mentioned above and to subsequently predict lifetimes by using simulated stress strain data. Starting point for deformation modeling is the well known viscoplastic model after Chaboche, which provides descriptions of isotropic and kinematic hardening, as well as dynamic and static recovery. The evolution equation for kinematic hardening model has been modified following the proposal of Ohno/Wang to better predict stress controlled cyclic strain accumulation, i.e. ratchetting. A damage variable has been included to represent tertiary creep according to the concept of Kachanov. Finally, the static recovery has been modified following Kindrachuk to account for strain induced ageing. The models parameters have been calibrated using isothermal test data only. The constitutive model has been validated by comparing experimental with predicted TMF stress-strain hystereses. Lifetime prediction is done with the TMF lifetime model proposed by Riedel. The model assumes that fatigue life is controlled by the propagation of short cracks. Besides pure fatigue, it takes the local creep deformations at the crack tip into account. The model is applied to a broad variety of isothermal and non isothermal tests over temperatures up to 950°C and different loading conditions. The evaluation shows that throughout satisfying results can be achieved using a limited number of model parameters for the whole test data base. T2 - 3rd International Workshop on Thermo-mechanical fatigue CY - BAM, Berlin, Germany DA - 27.04.2016 KW - TMF KW - Nickel base superalloy KW - Fatigue life assessment KW - Constitutive law PY - 2016 AN - OPUS4-35994 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Konert, Florian T1 - Evaluation of hydrogen effect on hardened and annealed 100Cr6 steel N2 - The use of hydrogen demands high safety requirements, since hydrogen can be absorbed by metallic materials and may cause hydrogen embrittlement (HE) under certain conditions. Slow strain rate (SSR) tensile testing is a widespread method to quantify the hydrogen-induced ductility loss of alloys. Here, the hollow specimen technique was used to evaluate the effect of 150 bar hydrogen on the tensile properties of solution annealed and hardened 100Cr6 steel, which is a common material for bearing systems. This technique reduces the required amount of hydrogen and minimizes the duration and costs of the tests performed compared to in-situ tensile tests in autoclaves. T2 - EPRI Workshop on Hydrogen Embrittlement 2024 CY - Oxford, UK DA - 23.06.2024 KW - Hydrogen KW - Hydrogen Embrittlement KW - Hollow Specimen Technique KW - 100Cr6 PY - 2024 AN - OPUS4-60476 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nietzke, Jonathan T1 - Influence of strain rate on the effect of hydrogen in pre-charged 316L stainless steel: A comparison of conventional and hollow specimen testing N2 - The growing demand for hydrogen requires an expansion of testing capabilities to assess the performance of metallic materials under hydrogen exposure. Considering only gaseous atmospheres, there is a variety of in-situ and ex-situ methods used to investigate the material behavior while or after exposed to hydrogen, respectively. Among these methods, a more conservative one is the in-situ testing at slow strain rates (SSRT) using conventional tensile specimens. While results obtained by a conservative procedure may be more applicable in many cases than those of ex-situ experiments, the tests are quite demanding, leading to limited testing capacities and high costs, especially for very slow strain rates. A possible solution that can enable in-situ testing at relatively low cost is the hollow specimen technique which gained increasing interest in the last decade. The main reasons are the minimal volume of hydrogen required and the elimination of a high-pressure hydrogen autoclave leading to significantly lower costs and enabling more laboratories worldwide to perform these tests. However, interpreting results from hollow specimens, especially when compared to conventional ones, remains a significant challenge. To address this, an experimental study was conducted using conventional and hollow specimens, both uncharged and pre-charged. Pre-charging was achieved using pure hydrogen (5.0, i.e. 99.999 %) at 100 bar and 300 °C for around 21 days. In order to obtain suitable reference specimens, other specimens were stored in argon at 100 bar and 300 °C for the same period of time. The tests were performed at various strain rates, down to 1E-6 1/s. While these ex-situ experiments are not directly comparable to in-situ tests with both types of specimens, they do provide some insights into the differences between the results of hollow and conventional specimens. Therefore, the elongation at fracture and reduction of area (RA) were compared, among other aspects. In addition, fractographical analyses were carried out using SEM images. Elongation at fracture was not significantly affected by hydrogen in conventional specimens, but it was slightly reduced in hollow specimens. RA, on the other hand, was lower for tests with hydrogen in both types of specimens across all strain rates. Moreover, the strain rate did not appear to influence hydrogen embrittlement in conventional specimens whereas in hollow specimens, tests conducted at higher strain rates (1E-4 1/s) showed a greater impact of hydrogen on elongation at fracture than those at lower strain rates (1E-6 1/s), which is contrary to the typical expectation. These findings suggest that the influence of hydrogen differs between conventional and hollow specimens, possibly due to factors such as surface roughness and differing stress states. However, further experiments are needed to fully understand these differences, including in-situ experiments to understand potential differences in hydrogen absorption between the two specimen types. T2 - EPRI Workshop on Hydrogen Embrittlement CY - Oxford, England, United Kingdom DA - 23.06.2024 KW - Stainless steel KW - Hollow specimen KW - Pre-charging KW - Hydrogen PY - 2024 AN - OPUS4-60494 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shikomba, Nikanor A1 - Böllinghaus, Thomas A1 - Konert, Florian A1 - Sobol, Oded A1 - Blasón Gonzalez, Sergio A1 - Ohijeagbon, Idehai Olayemi A1 - Krafft, Eike A1 - Staudt, Thorsten T1 - Resistance of welded low-alloyed pressure vessel and pipeline steels in gaseous hydrogen N2 - Green hydrogen has become an essential energy carrier to achieve a climate-neutral economy. The production, storage, transport and usage of green hydrogen require safe and sustainable facilities and systems. The present contribution provides a procedure guideline to investigate the compatibility of steel welds for pressurised gaseous hydrogen applications under quasi-static mechanical loads, utilising the slow strain rate test and hollow specimen technique. Exemplarily, a weld of the low-alloyed steel P355NL1 was investigated and compared to an X65 weld. The results indicate that the base metal exhibits a higher ductility than the weld metal for both steels. Generally, hydrogen-exposed specimens exhibited a reduced strain, as compared to reference specimens. The hydrogen degradation, evaluated by the hydrogen embrittlement index, was more pronounced in the weld metal compared to the base P355NL1 material, whereas the X65 exhibited a larger hydrogen degradation of the base material than in the weld metal. Fractographic analysis of the test specimens revealed that hydrogen causes a transition from ductile to brittle features. Generally, the results of this study indicate a mild but significant degradation of the mechanical properties in terms of the ductility of the welds in the respective pressurised hydrogen atmosphere. KW - Hydrogen-assisted cracking KW - Welded joint KW - Slow strain rate test KW - Hollow Specimen KW - Structural steel PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634138 DO - https://doi.org/10.1007/s40194-025-02074-7 SN - 0043-2288 SP - 1 EP - 15 PB - Springer CY - Berlin AN - OPUS4-63413 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Junias, Josua Kondja A1 - Holtappels, Kai A1 - Liebner, Christian A1 - Thewis, Max A1 - Askar, Enis A1 - Shaanika, Erasmus T1 - Hydrogen Mixtures Flammability Limits Prediction using Machine Learning Models N2 - Flammability characteristics of hydrogen mixtures have been extensively investigated at different initial conditions(temperature and pressure). Based on the available experimental datasets, empirical and semi-empirical models are commonly used to calculate flammability limits in dependance to initial conditions and mixture composition to reduce the experimental effort. However, unevenly distributed empirical data and the complex non-linear relationship characteristics of these data present significant challenges to empirical flammability limits prediction methods under various mixture initial conditions. Moreover, the empirical models and semi-empirical models only cover some influencing parameters, respectively. To address these issues, the present study adapts a machine learning (ML) approach for improving the hydrogen-air/oxygen-inert gas mixture flammability limits prediction at different conditions with a holistic approach. A Multi-Layer Perceptron (MLP) model was trained, validated, and tested using key input features such as flammability state, initial mixture temperature, equivalence ratio, inert gas concentration, adiabatic flame temperature, and Lewis numbers. Data augmentation techniques were conducted on experimental datasets to improve the predictive capability of the model. The models’ performance was compared with empirical flammability limit prediction methods. The goal is to deliver fast, reliable, and more accurate predictions across different scenarios with a single prediction model. Most importantly, the machine learning approach offers a cost-effective and robust alternative to existing empirical flammability limit prediction methods, thus also reducing the experimental effort for explosion limits determination. T2 - 11th International Conference on Hydrogen Safety (ICHS) 2025 CY - Seoul, South Korea DA - 22.09.2025 KW - Machine Learning KW - Flammability Limits PY - 2025 SN - 979 -12 -243 -0274 - 2 SP - 1389 EP - 1401 AN - OPUS4-64624 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz A1 - Günzel, Stephan A1 - Mair, Georg W. T1 - Discussion of creep phenomena during initial loading of type 4 composite pressure vessels N2 - To maintain the highest safety standards for compressed gas storage in composite pressure vessels, a deeper understanding of their ageing mechanism is required. In this study, two designs of type 4 cylinders were manufactured the only difference being the internal pressure function used during the filament winding process. Hence, their residual stress state and the quality of the composite layers varied. Ten pressure vessels were initially loaded under sustained pressure and increased temperature and later subjected to slow burst tests. Comparing the results with cylinders tested in a pristine state underlines a significant improvement in the performance of initially loaded cylinders of one of the designs. This phenomenon was caused by a significant decrease of the scattering of burst pressures within a sample. At the same time, a slight decrease of the burst pressures could be observed. An explanation of this behavior could be supported by strain measurements with fiber optic sensors, which were embedded in the composite material. The strains measured during the initial loading indicate a stress redistribution, which has an impact on the strength of the pressure vessel. Moreover, an increased stiffness during the slow burst tests after initial loading was observed that indicates a better exploitation of the individual layers of the composite structure. The study supports previous observations on the increased performance after initial loading and provides new insights into the strain development in creep effects in type 4 pressure vessels. T2 - Pressure Vessels & Piping Conference PVP2025 CY - Montreal, Quebec, Canada DA - 20.07.2025 KW - Type 4 pressure vessel KW - Creep KW - Fiber optic sensors KW - Slow burst test KW - Mechanics of composites PY - 2025 SN - 978-0-7918-8907-7 VL - 2025 SP - 1 EP - 7 PB - ASME AN - OPUS4-63897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kromm, Arne T1 - Werkstoffsichere Dickblechschweißung und KI N2 - Der Vortrag zeigt, welche Herausforderungen beim Schweißen sogenannter Dickblechverbindungen bestehen und welche Strategien zur Lösung genutzt werden können. Ansätze zur Fehlerprävention werden vorgestellt. Es wird dargestellt, wie KI-basierte Methoden die Fehlererkennung erleichtern. Letztlich werden Potentiale zur effizienten Fehlerbeseitigung aufgezeigt und der Anwendernutzen herausgestellt. T2 - Mitgliederversammlung der Forschungsvereinigung Stahlanwendung e. V. CY - Essen, Germany DA - 17.12.2025 KW - UP-Schweißen KW - Eigenspannungen KW - Künstliche Intelligenz KW - Reparatur PY - 2025 AN - OPUS4-65210 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröpfer, Dirk T1 - Residual stress evaluation using the contour method of an additive manufactured high-strength steel solid cuboid N2 - Direct Energy Deposition with Arc (DED-Arc) enables the weight-optimized and near-net-shape manufacturing of complex structures. Lightweight construction principles allow a reduction of CO2 emissions by saving time, costs, and resources. Further optimisations can be achieved by using high-strength steel. This allows for a reduction in wall thickness and optimisation of weight. However, manufacturing intricate geometries using high-strength steels poses challenges in managing residual stresses (RS), which are essential for ensuring the structural integrity of welded components. High residual stresses can increase the risk of cold cracking, arising from the complex interactions between material properties, process conditions, and component design. Despite the availability of suitable filler metals, the lack of comprehensive knowledge and guidelines on residual stress formation limits the industrial application. Therefore, in the present study, the contour method (CM) was used to analyse the full field longitudinal residual stresses in an solid cuboid component (dimensions: 120 × 50 × 35 mm³) manufactured by DED-Arc. The CM enables the analysis of the two-dimensional map of residual stresses normal to a cutting plane using a finite element model. For this purpose, a solid cuboid component was welded fully automatically with a high-strength solid wire specially adapted for DED-Arc (yield strength > 790 MPa) onto conventionally manufactured substrates made of S690QL. The residual stresses from CM in the volume are compared with residual stress analyses using X-Ray diffraction on the surface. Additionally, comparative data from previous studies on hollow cuboid structures was included in order to identify similarities and differences in the resulting stress state, and to complement and validate the CM results. These results demonstrate the significant influence of the geometry on the residual stress profiles within the solid cuboid in relation to the open hollow. T2 - 4th International Conference on Advanced Joining Processes 2026 CY - Coimbra, Portugal DA - 16.10.2025 KW - Residual stress KW - Contour method KW - DED-Arc/M KW - High-strength steel KW - Filler metals KW - Neutron diffraction PY - 2025 AN - OPUS4-65209 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pittner, Andreas A1 - Fabry, Cagtay A1 - Thiele, Marc A1 - Artinov, Antoni A1 - Rethmeier, Michael T1 - Automated Arc Welding and Sensor Based Quality Assessment for Enhancing Fatigue Strength and Structural Reliability of Offshore Wind Turbine Supports N2 - Offshore wind energy plays a crucial role in achieving a carbon dioxide free industrial sector in the coming decades. However, foundation systems for offshore wind turbines significantly impact the overall installation process, posing technical and regulatory challenges. Adopting lightweight design principles in steel construction such as dissolved load bearing structures in jacket foundations offers substantial potential for reducing resource consumption, particularly steel usage. This presentation explores the complete digitalization of welding manufacturing and testing processes, enabling fully automated production and data driven quality assessment of tubular nodes, which are vital components of jacket foundations. The study also investigates the relationship between seam geometry and fatigue strength inspired by bionic design principles. The results demonstrate that tubular nodes can be welded entirely automatically, accommodating geometric tolerances, and that seam geometries ca n be precisely manufactured according to suggestions from e.g. numerical models or other sources . These advancements significantly enhance the fatigue strength and service life of offshore wind turbine support structures. T2 - IIW Annual Assembly 2025 CY - Genova, Italy DA - 23.06.2025 KW - Automated gas metal arc welding KW - Quality assessment and control KW - Support structures KW - Fatigue PY - 2025 AN - OPUS4-65232 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Graebner, Maraike A1 - Giese, Marcel A1 - Lorenz, Svenja A1 - Treutler, Kai A1 - Schröpfer, Dirk A1 - Wesling, Volker A1 - Kannengießer, Thomas T1 - Wear resistance of modified NiMoCrSi claddings in relation to the resulting surface machinability via ultrasonic-assisted milling N2 - In the field of plastics processing, extruder screws are subjected to significant wear stresses. The extruder screw is the main wear component in those production machines and is usually coated with intermetallic wear protection alloys composed of Ni-based alloys, specifically Colmonoy C56 PTA (NiMoCrSi). There is a growing demand for providing an economic machinability of these alloys to achieve defined contours with a sufficient surface integrity. Recent investigations exhibit promising results applying ultrasonic milling for such hard-to-cut materials. The Colmonoy C56 is modified by various alloying additions Ti, Nb, Mo, Hf, and Al, and then cladded on a steel S355 via Plasma Transferred Arc process. The effect of alloying additions on the microstructure is analyzed regarding their resistance to abrasive and adhesive wear. With Miller test ASTM G75 the influence of alloying elements on resistance to abrasive wear for two abrasive materials is investigated (high-grade corundum F220 and quartz powder). The wear loss is not increased for additions of Nb and Ti compared to the base material C56. Modifications with Hf or Al reduces the resistance to abrasive wear and significantly increases material loss. The extruder screw is also subject to adhesive wear, which can be quantified by means of the pin-roll test. It is demonstrated that the addition of Hf, for example, contributes to a reduction in wear loss. Aim of the investigations is to find suitable modifications for the wear claddings of C56 for a sufficient machineability, without compemising the wear resistant. The machinability is considerably affected by the alloy additions, and is determined using ultrasonic-assisted milling. The addition of hafnium reduces machinability, i.e. significantly increases cutting forces. The incorporation of Nb exhibits a significant reduction of cutting forces, and results in reduced tool wear and an enhanced of surface integrity (roughness, density of defects, residual stresses). KW - Colmonoy C56 KW - PTA welding KW - Adhesive wear KW - Abrasive wear KW - Ultrasonic-assisted milling process KW - Surface integrity KW - Service life and efficiency KW - Substitution of critical raw materials PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651530 DO - https://doi.org/10.1016/j.wear.2025.205830 SN - 0043-1648 VL - 571 SP - 1 EP - 10 PB - Elsevier B.V. AN - OPUS4-65153 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gluth, Gregor T1 - Inhalt der Verordnungen für Heizungsanlagen - Überblick N2 - Seit dem 26.09.2015 gelten in Deutschland Anforderungen an die umweltgerechte Gestaltung und die Energiekennzeichnung von Heizgeräten und Verbundanlagen mit Heizgeräten. Der Vortrag stellt die zugrundeliegenden EU-Verordnungen und die sich ergebenden Konsequenzen überblicksmäßig vor. T2 - Kolloquium Marktüberwachung im Bereich Heizungsanlagen CY - Berlin, Germany DA - 06.04.2016 KW - Heizgeräte KW - Verbundanlagen KW - Umweltgerechte Gestaltung KW - Ökodesign KW - Energieverbrauchskennzeichnung PY - 2016 AN - OPUS4-36924 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Askar, Enis T1 - Hydrogen Safety - Explosion Protection for Hydrogen Applications N2 - In this lecture the safety related properties og hydrogen compared to other fuel gases and the explosion protection measures of avoiding flammable mixtures, avoiding ignition sources and mitigating the consequences of explosions when handling hydrogen and hydrogen mixtures are presented. The Joint European Summer School JESS 2021 addresses these issues by offering high quality graduate level courses on selected topics of vehicle technology, innovation & business development, safe handling of hydrogen, and modelling. The course content is tailored to the needs of a diverse audience: newcomers to the field, experienced students, and young professionals working at the forefront of fuel cell and hydrogen applications. T2 - Joint European Summer School (JESS) CY - Online meeting DA - 06.09.2021 KW - Explosionsschutz KW - Explosionsgrenzen KW - Zündenergie KW - Zündquellen KW - Auswirkung von Explosionen PY - 2021 AN - OPUS4-53808 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Askar, Enis A1 - Schröder, Volkmar A1 - Seemann, A. A1 - Schuetz, S. T1 - Power-to-Gas: Safety Characteristics of Hydrogen/NaturalGas-Mixtures N2 - Safety characteristics for explosion protection of natural gas/hydrogen mixtures relevant in connection with the Power2Gas technology were studied in this work. Lower explosion limits (LEL) and upper explosion limits (UEL), limiting oxygen concentrations (LOC), maximum experimental safety gaps (MESG), maximum explosion pressures (pmax) and maximum rates of pressure rise (dp/dt)max were determined experimentally in dependence of the hydrogen fraction. Adding hydrogen did mainly effect the UEL, LOC, MESG and (dp/dt)max. The mixtures become more "critical" concerning the explosion hazards with increasing hydrogen fraction. However, the dependency of the safety characteristics from the hydrogen fraction is mainly not linear. Adding up to 10% hydrogen to natural gas had nearly no effect on the safety characteristics. More significant effects on the safety characteristics were observed at hydrogen fractions of more than 25%. For example the explosion group changes from IIA to IIB. Considering the huge explosion region and very high (dp/dt)max of hydrogen compared to natural gas, even adding 50% hydrogen to natural gas has a rather small effect on these characteristics. Furthermore pmax of hydrogen/natural-gas mixtures can be calculated with good accuracy assuming ideal adiabatic conditions. EL and LOC of natural gas/hydrogen mixtures in ternary systems with inert gas and air were calculated in dependence of the type of inert gas with the so called “model of constant adiabatic flame temperature profiles”. KW - Explosion protection KW - Hydrogen safety KW - Hydrogen enriched natural gas KW - Energy storage PY - 2016 SN - 78-88-95608-39-6 DO - https://doi.org/10.3303/CET1648067 SN - 2283-9216 VL - 2016/48 SP - 397 EP - 402 PB - AIDIC AN - OPUS4-36788 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobol, Oded T1 - BAM’s role in materials science and hydrogen in metals: TOF-SIMS imaging N2 - Due to its low mass and high diffusivity in presence of compositional, thermal and mechanical gradients, hydrogen within a metallic microstructure can result in severe loss in ductility even at low concentrations and might lead eventually to a catastrophic and unpredictable failure of structural components during service. In this context, hydrogen mapping at the microscale is still considered among the most important challenges on the pathway towards a better understanding of the hydrogen transport and assisted cracking phenomena in metals, specifically in structural components, e.g. steels. Among the very few available techniques to localize hydrogen at the microscale, Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was proven to be a reliable tool. Based on the assumption that deuterium influence the microstructure similarly to hydrogen, in the following contribution ToF-SIMS was applied as the main technique to detect and locally map the deuterium distribution in several alloys: lean 2101 and standard 2205 duplex stainless steel (DSS), AISI 304L austenitic stainless steel and titanium 6Al-4V alloy. These alloys were selected as case studies in this work due to the wide use of them in many applications and environments which frequently provide critical conditions for hydrogen absorption and assisted degradation. The innovative design of in-situ and ex-situ experiments enabled us to elucidate the permeation, transport and trapping of deuterium in the microstructure in sub-micron resolution for the first time. In addition to the novel experimental setups, further progress was gained by applying computational multivariate data analysis (MVA) on the raw data and data fusion with high resolution structural characterization methods (scanning electron microscopy and electron back-scattered diffraction – SEM/EBSD). This combination allowed us to correlate the deuterium distribution and the influence on the microstructure. T2 - 4th Symposium on Innovative Measurement and Analysis for Structural Materials CY - Tokyo, Japan DA - 13.11.2018 KW - ToF-SIMS KW - Duplex stainless steel KW - Austenitic stainless steel KW - Principal Component Analysis KW - Data-fusion PY - 2018 UR - https://unit.aist.go.jp/tia-co/project/SIP-IMASM/sympo/2018/index.html AN - OPUS4-46867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epishin, A. I. A1 - Link, T. A1 - Nolze, Gert A1 - Svetlov, I. L. A1 - Bokshtein, B. S. A1 - Rodin, A. O. A1 - Saliwan Neumann, Romeo A1 - Oder, Gabriele T1 - Diffusion processes in multicomponent nickel-base superalloy-nickel system N2 - Optical and scanning electron microscopy, as well as electron microprobe analysis and electron backscatter diffraction, have been used to study diffusion processes that occur in a diffusion pair that consistsof a single-crystal CMSX-10 nickel-base superalloy and polycrystalline nickel, at temperatures of 1050–1250°C. It has been found that, in this system, the distributions of γ-stabilizing elements (Cr, Co, W, and Re) are described by the Boltzmann solution for diffusion between two semiinfinite plates of a binary alloy. The processing of these distributions has shown that the diffusion coefficients of Cr, Co, W, and Re in the multicomponent system are close to those in binary alloys of these elements with Ni. The diffusion redistribution of the elements leads to the dissolution of the γ′ phase in the nickel-base superalloy, growth of nickel grains toward the superalloy constituent of the diffusion pair, and the formation of porosity on both sides of the migrating interface, which is determined from a crystal misorientation of the alloy single crystal and nickel grains. KW - Ni-base superalloy KW - Interface KW - Diffusion KW - Phase transformation KW - Porosity PY - 2014 SN - 0031-918X VL - 115 IS - 1 SP - 21 EP - 29 AN - OPUS4-37980 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Askar, Enis T1 - Ignition Behaviour and Challenges for Hydrogen Safety N2 - The presentation is divided in two parts. In the first part the significance of mechanical impacts as ignition source for hydrogen containing atmospheres is shown and recent results of a research project evaluating ignition probabilities under different conditions is presented. In the second part future challenges in the field of hydrogen safety are discussed. Finally, the German National Hydrogen Safety Alliance is introduced. T2 - Hydrogen Online Workshop 2024 CY - Online meeting DA - 05.06.2024 KW - Explosion protection KW - Mechanical impacts KW - Ignition source KW - German National Alliance for Hydrogen Safety PY - 2024 AN - OPUS4-60288 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Schröder, Volkmar A1 - Askar, Enis A1 - Habib, Abdel Karim A1 - Tashqin, T. T1 - Sicherheitstechnische Eigenschaften von Erdgas-Wasserstoff-Gemischen N2 - Bei der Power-to-Gas-Technologie wird überschüssiger Strom aus erneuerbaren Energien durch Elektroly-se von Wasser in Wasserstoff umgewandelt. Dieser Wasserstoff kann als „chemischer Energiespeicher“ dienen und rückverstromt werden oder aber in das Erdgasnetz eingespeist werden. Die BAM hat die Aus-wirkungen von Wasserstoffzusätzen zum Erdgas im Hinblick auf den Explosionsschutz untersucht und sicherheitstechnische Kenngrößen für Erdgas-Wasserstoff-Gemische bestimmt. Untersucht wurden die Explosionsgrenzen, die Sauerstoffgrenzkonzentrationen, die maximalen Explosi-onsdrücke, die KG-Werte und die Normspaltweiten. Für die Messungen sind zwei Modellgase eingesetzt worden, reines Methan und ein Modell-Erdgas mit Anteilen höherer Kohlenwasserstoffe. Sie repräsentie-ren die Bandbreite der in Deutschland eingesetzten Erdgase. Die Untersuchungen ergaben, dass bei einem Zusatz von bis zu 10 Mol-% Wasserstoff keine der untersuchten Kenngrößen relevant beeinflusst wird. Die Gemische haben nur geringfügig erweiterte Explosionsbereiche und bleiben, wie die reinen Erdgase, in der Explosionsgruppe IIA. Auch die maximalen Explosionsdrücke und die zeitlichen Druckanstiege bei den Gasexplosionen werden nur wenig beeinflusst. Vergleichende Berechnungen zur Festlegung von explosionsgefährdeten Bereichen (Ex-Zonen) auf Basis von Gasausbreitungsberechnungen ergaben ebenfalls nur geringfüge Unterschiede im Rahmen der Fehler-toleranz für Erdgas und Erdgas-Wasserstoff-Gemische mit bis zu 10 Mol-% Wasserstoff. Die Berechnun-gen sind in der BAM nach einem Freistrahlmodell von Schatzmann und mit dem häufig bei Gasnetzbetrei-bern eingesetzten e.BEx-Tool® durchgeführt worden. Der Einsatz von Gaswarngeräten, die für reines Erdgas geeignet sind, ist für Erdgas-Wasserstoff-Gemische mit bis zu 10 Mol-% Wasserstoff grundsätzlich möglich, erfordert aber eine gesonderte Sicher-heitsbewertung und ggf. eine Nachkalibrierung. N2 - Power-to-Gas technology is used to convert excess power from renewable energies to hydrogen by means of water electrolysis. This hydrogen can serve as "chemical energy storage" and be converted back to elec-tricity or be fed into the natural gas grid. BAM has studied the addition of hydrogen to natural gas in view of explosion protection and has determined safety characteristics for natural gas-hydrogen mixtures. BAM investigated the explosion limits, the limiting oxygen concentrations, the maximum explosion pres-sures, KG values and the MESG. Two model gases have been investigated, pure methane and a model gas with portions of higher hydrocarbons. They represent the range of natural gases which are used in Germa-ny. The investigations have shown that none of the examined characteristics is affected significantly by the addition of up to 10 mol% hydrogen. The explosion ranges are increased only slightly and the mixtures remain in explosion group IIA; as is pure natural gas. Also the maximum explosion pressure and the rates of pressure rise of gas explosions are almost unaffected. Comparative calculations – on the basis of gas dispersion calculations – to determine hazardous areas (explosion zones) for pure natural gas and natural gas-hydrogen mixtures with up to 10 mol% hydrogen, also revealed only minor differences within the margin of error of the calculation methods. The calcula-tions were executed at BAM according to the free jet model from Schatzmann and with the e.BEx-Tool®, often applied by gas grid operators. In principle, gas detectors that are suitable for natural gas can be used for natural gas-hydrogen mixtures with a maximum of 10 mol% hydrogen. However, this requires a separate safety assessment and, if nec-essary, a recalibration. KW - Power-to-Gas KW - Erneuerbare Energien KW - Energiespeicherung KW - Wasserstofftechnologie KW - Explosionsschutz KW - Erdgas-Wasserstoff-Gemische PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-372977 SP - 1 EP - 36 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-37297 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Volkmar A1 - Askar, Enis A1 - Tashqin, T. T1 - Sicherheitstechnische Eigenschaften von Gemischen aus Wasserstoff und Erdgas N2 - Bei der Power-to-Gas-Technologie wird überschüssiger Strom aus erneuerbaren Ener-gien durch Elektrolyse von Wasser in Wasserstoff umgewandelt. Dieser Wasserstoff kann als „chemischer Energiespeicher“ dienen und rückverstromt werden oder aber in das Erdgasnetz eingespeist werden. Die BAM hat die Auswirkungen von Wasserstoffzu-sätzen zum Erdgas im Hinblick auf den Explosionsschutz untersucht und sicherheitstechnische Kenngrößen für Erdgas-Wasserstoff-Gemische bestimmt. Von besonderem Interesse waren dabei die Explosionsgrenzen, die Sauerstoffgrenzkonzentration, die maximalen Explosionsdrücke, die KG-Werte und die Normspaltweiten. Für die Messungen sind zwei Modellgase eingesetzt worden, reines Methan und ein Modell-Erdgas mit Anteilen höherer Kohlenwasserstoffe. Sie repräsentieren die Bandbreite der in Deutschland eingesetzten Erdgase. Die Untersuchungen ergaben, dass bei einem Zusatz von bis zu 10 Mol-% Wasserstoff keine der untersuchten Kenngrößen signifikant beeinflusst wird. Die Gemische haben nur geringfügig erweiterte Explosionsbereiche und bleiben, wie die reinen Erdgase, in der Explosionsgruppe IIA. Auch die maximalen Explosionsdrücke und die zeitlichen Druckanstiege bei den Gasexplosionen werden nur wenig beeinflusst. T2 - Kolloquium zur chemischen und physikalischen Sicherheitstechnik CY - Berlin, Germany DA - 14.06.2016 KW - Wasserstoff KW - Erdgasnetz KW - Energiespeicherung KW - Explosionsschutz KW - Sicherheitstechnische Kenngrößen PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-373099 SN - 978-3-9817853-5-7 SN - 0938-5533 VL - 2016 SP - 60 EP - 67 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin, Germany AN - OPUS4-37309 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Askar, Enis T1 - Sicherheitstechnische Eigenschaften von Erdgas/Wasserstoff-Gemischen - Auswirkungen auf den Explosionsschutz N2 - Hinsichtlich ihrer sicherheitstechnischen Kenngrößen (STK) unterscheiden sich Wasserstoff und Erdgas zum Teil stark. Im Vortrag werden verschiedene STK von Erdgas/Wasserstoff-Gemischen im Abhängigkeit des Wasserstoffanteils vorgestellt und die Auswirkung der Beimischung von Wasserstoff zum Erdgas auf die Wirksamkeit von Explosionsschutzmaßnahmen erläutert. T2 - DVGW-Kongress 2021 "Gasinfrastruktur für Erdgas-H2-Gemische" CY - Online meeting DA - 07.10.2021 KW - Explosionsschutz KW - Explosionsgrenzen KW - Zündenergie KW - Power to Gas KW - Erdgasnetz KW - Zündquellen PY - 2021 AN - OPUS4-53725 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mosquera Feijoo, Maria T1 - Thermal-mechanical fatigue of oxide scales in cyclic water vapor oxidation of 9-12 % Cr steels N2 - Ferritic-martensitic steels with 9-12 % Cr-content are widely used as high temperature construction materials in power plant due to their high temperature properties such as creep resistance, strength, and favorable oxidation resistances. However, typical operating conditions include cyclic thermal/mechanical loading, and as a result the oxide scale might fail; cracks are formed and the oxide scale is spalled off. The oxide spalls can cause steam tube blocking and local thermal stresses, which might provoke shorter component service life. This work investigates the scale spallation behavior of ferritic-martensitic steels under cyclic load condition between 320°C and 620°C for up to 210 cycles in pure steam. All samples were isothermally pre-oxidized at 620°C for 500 h in water steam with 30 bar pressure to create an initial magnetite layer with low porosity. Different sample shapes, rectangular coupons, full rings and U-shape segments, are investigated to evaluate the impact of the geometry on these conditions. After oxidation experiments the oxidation kinetics in terms of mass change, metal loss and thickness scale is determined. In addition, the integrity of the oxide layer as well as its adherence to the matrix are characterized by modified hardness tests and scratch tests. Breakage of the layers at lower applied forces indicates a substantial loss of adhesion strength at intermediate cycle numbers. T2 - EUROCORR 2017 CY - Prague, Czech-Republic DA - 03.09.2017 KW - Geometry influence KW - Therma-mechanical fatigue KW - Oxide layer KW - Cyclic test KW - Scale adherence PY - 2017 AN - OPUS4-42635 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Röhsler, Andreas A1 - Sobol, Oded A1 - Hänninen, H. A1 - Böllinghaus, Thomas T1 - In-situ ToF-SIMS analyses of deuterium re-distribution in austenitic steel AISI 304L under mechanical load N2 - Hydrocarbons fuel our economy. Furthermore, intermediate goods and consumer products are often hydrocarbon-based. Beside all the progress they made possible, hydrogen-containing substances can have severe detrimental effects on materials exposed to them. Hydrogen-assisted failure of iron alloys has been recognised more than a century ago. The present study aims to providing further insight into the degradation of the austenitic stainless steel AISI 304L (EN 1.4307) exposed to hydrogen. To this end, samples were electrochemically charged with the hydrogen isotope deuterium (2H, D) and analysed by scanning electron microscopy (SEM), electron back-scatter diffraction (EBSD) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). It was found that deuterium caused a phase transformation from the original γ austenite into ε- and α’-martensite. Despite their low solubility for hydrogen, viz. deuterium, the newly formed phases showed high deuterium concentration which was attributed to the increased density of traps. Information about the behaviour of deuterium in the material subjected to external mechanical load was gathered. A four-point-bending device was developed for this purpose. This allowed to analyse in-situ pre-charged samples in the ToF-SIMS during the application of external mechanical load. The results indicate a movement of deuterium towards the regions of highest stress. KW - ToF-SIMS KW - Hydrogen KW - Deuterium KW - AISI 304L KW - EBSD PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505142 DO - https://doi.org/10.1038/s41598-020-60370-2 VL - 10 IS - 1 SP - 3611 PB - Nature AN - OPUS4-50514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Konert, Florian A1 - Campari, Alessandro A1 - Nietzke, Jonathan A1 - Sobol, Oded A1 - Paltrinieri, Nicola A1 - Alvaro, Antonio T1 - Evaluation of the tensile properties of X65 pipeline steel in compressed gaseous hydrogen using hollow specimens N2 - Hydrogen has great potential on the path towards decarbonization of the energy and transport sectors and can mitigate the urgent issue of global warming. It can be sustainably produced through water electrolysis with potentially zero emissions, and efficiently used (e.g., in fuel cell systems). Despite its environmental advantages, hydrogen-metal interactions could result in the degradation of the mechanical properties of several structural materials. In order to determine the magnitude of the material degradation in relation to hydrogen exposure, extensive material testing is required. The standardized procedure for in-situ testing for the quantification of the impact of compressed gaseous hydrogen (CGH2) relies on the utilization of an autoclave around the tested specimen. Such test set-up is complex, expensive, time-consuming and requires special equipment, trained personnel, and strict safety procedures. A relatively recent method to circumvent these issues and provide affordable results consists of using hollow specimens, thus applying the hydrogen pressure inside rather than outside the specimen. It allows to reduce the volume of hydrogen by several orders of magnitude and to perform the tests more efficiently and in a safer manner. This study focuses on evaluating the tensile properties of X65 vintage pipeline steel tested in a high-pressure hydrogen environment using hollow specimens. Tests are performed in 6 MPa H2 and Ar at the nominal strain rate of 10−6 s−1 to evaluate the reduced area at fracture and the elongation loss. The effect of surface finishing on crack initiation and propagation is investigated by comparing two different manufacturing techniques. In this way, this study provides insights into the applicability of a novel, reliable, and safe testing method which can be used to assess the hydrogen-assisted ductility loss in metallic materials. KW - Mechanical Engineering KW - Hydrogen Embrittlement KW - SSRT KW - Hollow specimen KW - Pipeline steel KW - In-situ tensile test PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595887 DO - https://doi.org/10.1016/j.prostr.2024.01.074 SN - 2452-3216 VL - 54 SP - 1 EP - 8 PB - Elsevier B.V. AN - OPUS4-59588 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Konert, Florian A1 - Wieder, Frank A1 - Nietzke, Jonathan A1 - Meinel, Dietmar A1 - Böllinghaus, Thomas A1 - Sobol, Oded T1 - Evaluation of the impact of gaseous hydrogen on pipeline steels utilizing hollow specimen technique and μCT N2 - The high potential of hydrogen as a key factor on the pathway towards a climate neutral economy, leads to rising demand in technical applications, where gaseous hydrogen is used. For several metals, hydrogen-metal interactions could cause a degradation of the material properties. This is especially valid for low carbon and highstrength structural steels, as they are commonly used in natural gas pipelines and analyzed in this work. This work provides an insight to the impact of hydrogen on the mechanical properties of an API 5L X65 pipeline steel tested in 60 bar gaseous hydrogen atmosphere. The analyses were performed using the hollow specimen technique with slow strain rate testing (SSRT). The nature of the crack was visualized thereafter utilizing μCT imaging of the sample pressurized with gaseous hydrogen in comparison to one tested in an inert atmosphere. The combination of the results from non-conventional mechanical testing procedures and nondestructive imaging techniques has shown unambiguously how the exposure to hydrogen under realistic service pressure influences the mechanical properties of the material and the appearance of failure. KW - Energy Engineering and Power Technology KW - Condensed Matter Physics KW - Fuel Technology KW - Renewable Energy, Sustainability and the Environment KW - µCT KW - Hollow Specimen Technique KW - Hydrogen Embrittlement PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595077 DO - https://doi.org/10.1016/j.ijhydene.2024.02.005 SN - 0360-3199 VL - 59 SP - 874 EP - 879 PB - Elsevier B.V. AN - OPUS4-59507 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epishin, A. A1 - Link, T. A1 - Svetlov, I. L. A1 - Nolze, Gert A1 - Saliwan Neumann, Romeo A1 - Lucas, H. T1 - Mechanism of porosity growth during homogenisation in single crystal nickel-based superalloys N2 - Several mechanisms for porosity growth in single crystal nickel-based superalloys during homogenisation heat treatment have been proposed in the literature. They were carefully checked using different experimental methods, namely quantitative light microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and density measurements. It is shown that the main mechanism is the Kirkendall–Frenkel effect, i.e. generation of voids due to uncompensated efflux of Al atoms from dissolving γ/γ′-eutectic areas. The Al diffusion is supported by the afflux of vacancies from surrounding γ-matrix which results in porosity growth. This conclusion is confirmed by the estimation of the vacancy afflux towards the dissolving eutectic. KW - Ni-base superalloy KW - Eutectic KW - Vacancies KW - Porosity PY - 2013 VL - 104 IS - 8 SP - 776 EP - 782 PB - Carl Hanser Verlag AN - OPUS4-37983 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Leo, Reinhold T1 - Duplex stainless steels - Compatibility for high-pressure hydrogen applications N2 - Duplex Stainless Steels (DSS) are an essential component used in the construction of transportation pipelines because of their many distinctive qualities. The choice of DSS for a particular hydrogen application mainly depends on its susceptibility level to Hydrogen Assisted Cracking (HAC). Several mechanisms have been proposed to describe the occurring microscale processes behind HAC, and these include metastable phase transformation, Hydrogen Enhanced Localized Plasticity (HELP), and Hydrogen Enhanced Decohesion (HEDE). This contribution describes the path to ascertain if DSS is suitable for high-pressure gaseous hydrogen applications. The interplay between several critical factors that result in HAC was examined using high-pressure gaseous hydrogen charging, Electron Backscatter Diffraction (EBSD), tensile testing and hydrogen concentration measurements using Carrier Gas Hot Extraction (CGHE). T2 - Third German-African Green Hydrogen Forum 2025 CY - Bernburg (Saale), Germany DA - 23.09.2025 KW - Hydrogen Assisted Cracking KW - High Pressure Hydrogen KW - Duplex Stainless Steels KW - Hollow Specimen Technique PY - 2025 AN - OPUS4-64302 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Askar, Enis A1 - Grunewald, Thomas T1 - Entzündung von wasserstoffhaltigen Atmosphären durch mechanisch erzeugte Funken („HySpark“) N2 - Im Zuge der Energiewende finden Wasserstofftechnologien in der industriellen Praxis und im öffentlichen Raum immer mehr Anwendung. Beim Einsatz von Wasserstoff als Ersatz für andere fossile Energieträger wie Erdgas müssen u.a. Explosionsschutzmaßnahmen überprüft und angepasst werden. Eine Art von Explosionsschutzmaßnahmen ist die Vermeidung von Zündquellen. Gemäß den einschlägigen Regelwerken ist die Bildung von Funken oder heißen Aufschlagstellen beim mechanischen Schlag eine mögliche Zündquelle, die vor allem beim Wasserstoff berücksichtigt werden muss. Die Zündwirksamkeit ist dabei u.a. stark von der Werkstoffpaarung und der kinetischen Schlagenergie abhängig. Der Einsatz von funkenarmen Werkzeugen aus schwer oxidierbaren Nicht-Eisen-Metallen in explosionsgefährdeten Bereichen kann z.B. eine Maßnahme sein, um diese Zündquelle zu vermeiden und wird als solche in den Regelwerken benannt. Es gibt aber kaum Quellen, die dabei helfen die Zündwirksamkeit bei Schlägen mit heterogenen Materialpaarungen einzuschätzen. In dieser Arbeit wurde zu diesem Zweck die Zündwirksamkeit von mechanischen Schlägen mit unterschiedlichen, auch nicht-metallischen Schlagpartnern in wasserstoffhaltigen Atmosphären systematisch untersucht. KW - Explosionsschutz KW - Zündquelle KW - ATEX KW - Erdgas KW - Mechanischer Schlag PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579869 DO - https://doi.org/10.26272/opus4-57986 SP - 1 EP - 28 AN - OPUS4-57986 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baer, Wolfram A1 - Wossidlo, Peter T1 - Experimental determination and analysis of dynamic fracture toughness data of ductile cast iron N2 - Ductile Cast Iron materials (DCI) have become important structural materials. Neverthe-less, to draw maximum benefit from DCIs property potential, tailored testing methods must be provided. The established dynamic Jd-R and CTOD 5d-R curve procedures are based on material specifically developed, independent experimental techniques but pro-vide almost matching results. This can be seen as additional validation of the Jd procedure which was mandatory. T2 - 14th International Conference on Fracture (ICF 14) CY - Rhodes, Greece DA - 18.07.2017 KW - Ductile cast iron KW - Fracture mechanics KW - Dynamic loading KW - Crack resistance curve KW - CTOD KW - J-integral PY - 2017 SP - Track 3, 1 EP - 2 AN - OPUS4-42721 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baer, Wolfram A1 - Holzwarth, Marcel A1 - Mayer, Uwe ED - Vormwald, Michael T1 - Untersuchung des Master Curve-Konzepts für ferritisches Gusseisen mit Kugelgraphit: Versuchswerkstoff und erste Ergebnisse an SE(B)140-Großproben N2 - In einem laufenden Kooperationsprojekt zwischen der BAM Berlin und der MPA Stuttgart wird das probabilistische Master Curve (MC) Konzept nach ASTM E1921 hinsichtlich seiner Übertragbarkeit auf ferritisches Gusseisen mit Kugelgraphit (DCI) untersucht. Zielsetzung ist die Bereitstellung einer Vorgehensweise zur Bestimmung und Bewertung der dynamischen Bruchzähigkeit von DCI im Übergangsbereich. In diesem Beitrag wird der Versuchswerkstoff der Festigkeitsklasse GJS-400 näher vorgestellt. Ferner werden erste Ergebnisse von zwei bruchmechanischen Versuchsserien an SE(B)140-Großproben bei Belastungsraten von ca. 6∙104 MPa√ms-1 bei -40 °C und -60 °C präsentiert. T2 - 56. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit CY - Kassel, Germany DA - 20.02.2024 KW - Dynamische Beanspruchung KW - Bruchmechanik KW - Master Curve-Konzept KW - Gusseisen mit Kugelgraphit PY - 2024 DO - https://doi.org/10.48447/BR-2024-BB SP - 49 EP - 58 PB - DVM-Verlag CY - Berlin AN - OPUS4-59518 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzwarth, Marcel A1 - Baer, Wolfram A1 - Mayer, Uwe A1 - Weihe, Stefan ED - Vormwald, Michael T1 - Untersuchung des Master Curve-Konzepts für ferritisches Gusseisen mit Kugelgraphit: Kritische Belastungsrate und erste Ergebnisse an C(T)-Proben N2 - Im laufenden Verbundprojekt MCGUSS untersuchen dieProjektpartner MPA Stuttgart und BAM Berlin das probabilistische Master Curve (MC) Konzept nach ASTM E1921 hinsichtlich seiner Übertragbarkeit auf ferritisches Gusseisen mit Kugelgraphit (DCI). Ziel des Projektes ist die Entwicklung einer Methode zur Bestimmung und Bewertung der dynamischen Bruchzähigkeit von DCI im Übergangsbereich. In diesem Beitrag werden die Eigenschaften des verwendeten Werkstoffs der Festigkeitsklasse GJS-400 vorgestellt und die sich daraus ergebenden Probenentnahmestellen näher erläutert. Weiterhin werden erste Ergebnisse der C(T)25-Versuchsserien vorgestellt, die bei Belastungsraten von ca. 5∙103 MPa√ms-1, 5∙104 MPa√ms-1 und 5∙105 MPa√ms-1 und einer Temperatur von -40 °C durchgeführt wurden. T2 - 56. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit CY - Kassel, Germany DA - 20.02.2024 KW - Dynamische Belastung KW - Master Curve KW - Gusseisen KW - C(T)-Proben PY - 2024 SP - 37 EP - 47 PB - DVM Verlag CY - Berlin AN - OPUS4-59519 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baer, Wolfram T1 - Untersuchung des Master Curve-Konzepts für Ferritisches Gusseisen mit Kugelgraphit: Versuchswerkstoff und erste Ergebnisse von SE(B)140-Grossproben N2 - In einem laufenden Kooperationsprojekt zwischen der BAM Berlin und der MPA Stuttgart wird das probabilistische Master Curve (MC) Konzept nach ASTM E1921 hinsichtlich seiner Übertragbarkeit auf ferritisches Gusseisen mit Kugelgraphit (DCI) untersucht. Zielsetzung ist die Bereitstellung einer Vorgehensweise zur Bestim-mung und Bewertung der dynamischen Bruchzähigkeit von DCI im Übergangsbe-reich. In diesem Beitrag wird der Versuchswerkstoff der Festigkeitsklasse GJS-400 näher vorgestellt. Ferner werden erste Ergebnisse von zwei bruchmechanischen Versuchsserien an SE(B)140-Großproben bei Belastungsraten von ca. 6∙104 MPa√ms-1 bei -40 °C und 60 °C präsentiert. T2 - Jahrestagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit CY - Kassel, Germany DA - 20.02.2024 KW - Bruchzähigkeit KW - Sprödbruch KW - Master Curve KW - Gusseisen mit Kugelgraphit KW - ASTM E1921 PY - 2024 AN - OPUS4-59860 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mayer, Uwe T1 - Untersuchung des Master Curve-Konzeptes für ferritisches Gusseisen mit Kugelgraphit N2 - In dem Poster werden der Forschungsansatz, die Ziele, das Untersuchungsprogramm und die erwarteten Ergebnisse des BMUV-Forschungsvorhabens MCGUSS "Untersuchung des Master Curve-Konzeptes für ferritisches Gusseisen mit Kugelgraphit" vorgestellt. Mit Blick auf bruchmechanische Sicherheitsbewertungen in der Kerntechnik werden Stähle momentan mit dem deterministischen ASME-Referenzkurvenkonzept, ergänzt durch das probabilistische Master Curve-Konzept nach ASTM E1921, bewertet. Das Master Curve-Konzept wird bereits für die Bewertung von ferritischen Schmiedestahlbehältern verwendet. Bewertungsmethoden für ferritisches Gusseisen mit Kugelgraphit sind im Moment unvollständig. Normen wie die nationale BDG-Richtlinie P300 oder der internationale ASME-Code, Sect. III, Div. 3, WC-2330 decken Sprödbruch nicht ausreichend ab. Die Verwendung des Master Curve-Konzepts für ferritisches Gusseisen mit Kugelgraphit würde eine bruchmechanische Bewertung via einer KJc,d Verteilung erlauben und gleichzeitig Größeneffekte und einen Temperaturbereich von 100 K berücksichtigen. T2 - GRS-Projektstatusgespräch 2023 CY - Karlsruhe, Germany DA - 06.11.2023 KW - Dynamische Bruchzähigkeit KW - Sprödbruch KW - Gusseisen mit Kugelgraphit KW - Master Curve PY - 2023 AN - OPUS4-59060 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mayer, Uwe T1 - Untersuchung des Master Curve-Konzeptes für ferritisches Gusseisen mit Kugelgraphit N2 - In dem Vortrag werden der Forschungsansatz, die Ziele, das Untersuchungsprogramm und die erwarteten Ergebnisse des BMUVForschungsvorhabens MCGUSS "Untersuchung des Master Curve-Konzeptes für ferritisches Gusseisen mit Kugelgraphit" vorgestellt. Mit Blick auf bruchmechanische Sicherheitsbewertungen in der Kerntechnik werden Stähle momentan mit dem deterministischen ASME Referenzkurvenkonzept, ergänzt durch das probabilistische Master Curve-Konzept nach ASTM E1921, bewertet. Das Master Curve-Konzept wird bereits für die Bewertung von ferritischen Schmiedestahlbehältern verwendet. Bewertungsmethoden für ferritisches Gusseisen mit Kugelgraphit sind im Moment unvollständig. Normen wie die nationale BDG-Richtlinie P300 oder der internationale ASME-Code, Sect. III, Div. 3, WC-2330 decken Sprödbruch nicht ausreichend ab. Die Verwendung des Master Curve-Konzepts für ferritisches Gusseisen mit Kugelgraphit würde eine bruchmechanische Bewertung via einer KJc,d Verteilung erlauben und gleichzeitig Größeneffekte und einen Temperaturbereich von 100 K berücksichtigen. T2 - GRS-Projektstatusgespräch 2023 CY - Karlsruhe, Germany DA - 06.11.2023 KW - Dynamische Bruchzähigkeit KW - Master Curve KW - Gusseisen mit Kugelgraphit KW - Sprödbruch PY - 2023 AN - OPUS4-59061 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzwarth, M. T1 - First results for the modification of the master curve concept for ferritic ductile cast iron N2 - Within the scope of fracture mechanics safety, ferritic ductile cast iron (DCI) does currently not have an established and validated method to determine and assess dynamic fracture toughness values in the ductile-to-brittle transition regime. For this reason, the applicability of the fracture mechanics Master Curve concept according to ASTM E1921 to DCI is being investigated in a joint research project between MPA Stuttgart and BAM Berlin. To investigate the applicability of the Master Curve concept for DCI, a DCI material of grade GJS-400 has been procured via a detailed manufacturing specification. From this material test specimens of various geometries and sizes (Tensile, Charpy-V, Pellini, SE(B)10, SE(B)25, SE(B)140, DC(T)9, C(T)25 and C(T)50) were produced. In total, about 500 test specimens will be tested to investigate and validate the Master Curve Concept as well as other assumptions (e.g. size effects, Weakest-Link, Weibull distribution) for DCI. While the whole project has not yet concluded, several work packages have yet been completed. Selected test results using C(T)25 specimens are presented. T2 - European Conference on Fracture 2024 CY - Zagreb, Croatia DA - 26.08.2024 KW - Dynamic fracture toughness KW - Ductile cast iron KW - Master curve PY - 2024 AN - OPUS4-61451 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baer, Wolfram A1 - Ohm, Katrin A1 - Holzwarth, Marcel A1 - Mayer, Uwe T1 - Master Curve-Auswertungen und fraktographische Analysen zum Bruchmechanismus – neue Ergebnisse zur Untersuchung des Master Curve Konzepts für ferritisches Gusseisen mit Kugelgraphit bei dynamischer Beanspruchung (Projekt MCGUSS) N2 - In diesem Beitrag werden erste Master Curve (MC)-Auswertungen und fraktographische Analysen zum Bruchmechanismus aus dem laufenden Kooperationsprojekt MCGUSS zwischen der BAM Berlin und der MPA Stuttgart diskutiert. Für zwei SE(B)140-Großprobenversuchsserien mit je 6-8 Versuchen bei -40 °C bzw. -60 °C und Belastungsraten von 5-8x10^4 MPa√m/s wurden Referenztemperaturen T0 bestimmt. Ergänzt wird dies für erste Versuchsreihen an SE(B)25-Kleinproben, die bei -60 °C und Belastungsraten von ca. 2x10^5 MPa√m/s geprüft wurden. An ausgewählten Bruchflächen dieser Versuche wurden detaillierte fraktographische REM-Analysen vorgenommen. Im Vordergrund stand die Charakterisierung des Bruchmechanismus in Abhängigkeit von den Einflussfaktoren Temperatur und Probengröße. In Richtung der Zähigkeitstieflage werden die Analysen komplettiert durch die Ergebnisse von zwei SE(B)140-Großprobenversuchen bei -100 °C bzw. -140 °C und Belastungsraten von ca. 5-8x10^4 MPa√m/s. T2 - 57. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit CY - Köln, Germany DA - 18.02.2025 KW - Dynamische Beanspruchung KW - Bruchmechanik KW - Master Curve-Konzept KW - Gusseisen mit Kugelgraphit PY - 2025 DO - https://doi.org/10.48447/BR-2025-467 SP - 113 EP - 122 PB - DVM-Verlag CY - Berlin AN - OPUS4-62554 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzwarth, Marcel A1 - Baer, Wolfram A1 - Mayer, Uwe A1 - Weihe, Stephan T1 - Investigation of the Master Curve Concept for Ferritic Ductile Cast iron N2 - Within fracture mechanics safety assessment for steels in nuclear technology, the probabilistic master curve (MC) concept according to ASTM E1921 is currently used for quasi-static loading conditions as a supplement to the established deterministic ASME reference curve concept. However, for ductile cast iron (DCI), a systematic review of potential modifications to the assumptions and the procedure according to ASTM E1921 and an associated validation are still lacking. For this reason, the application of the fracture mechanics MC concept to ferritic ductile cast iron is being investigated in a recently started joint research project between MPA Stuttgart and BAM Berlin. According to the IAEA guidelines SSG 26, the safety assessment of DCI containers for transport as well as storage of radioactive materials is based on the fracture mechanics criterion of general crack initiation exclusion. Within this context, the focus of the current research project is on the further development of brittle fracture safety assessment methods. Therefore, a methodology shall be established to determine and assess dynamic fracture toughness values of DCI in the ductile-to-brittle transition regime, using samples extracted from a component. For the experimental program, a DCI material will be produced as it is generally used for transport and storage containers. A basic mechanical-technological material characterization consisting of tensile, Charpy and Pellini tests is planned and a comprehensive fracture mechanics test program was compiled covering dynamic testing of DC(T)9, C(T)25, C(T)50, SE(B)10, SE(B)25, and SE(B)140 specimens. Numerical analyses of different specimen geometries and test setups are planned to investigate the influences of stress triaxiality and loading rate. Throughout the experimental program, the microstructure-property relationship will be investigated based on quantitative metallographic and fractographic analyses. Finally, different MC assessment strategies will be considered and modifications will be made if necessary. T2 - 21st International Symposium ASTM/ESIS Symposium on Fatigue and Fracture Mechanics CY - Washington, D.C., USA DA - 08.11.2023 KW - Dynamic Fracture Toughness KW - Cleavage fracture KW - Master Curve Concept KW - Ductile Cast Iron PY - 2023 AN - OPUS4-59063 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzwarth, Marcel T1 - Investigation of the Master Curve Concept for Ferritic Ductile Cast Iron N2 - Within fracture mechanics safety assessment for steels in nuclear technology, the probabilistic master curve (MC) concept according to ASTM E1921 is currently used for quasi-static loading conditions as a supplement to the established deterministic ASME reference curve concept. However, for ferritic ductile cast iron (DCI), a systematic review of potential modifications to the assumptions and the procedure according to ASTM E1921 and an associated validation are still lacking. For this reason, the application of the fracture mechanics MC concept to ferritic ductile cast iron is being investigated in a joint research project between MPA Stuttgart and BAM Berlin. According to IAEA SSG-26, the safety assessment of DCI containers for transport as well as storage of radioactive materials is based on the fracture mechanics criterion of general crack initiation exclusion. Within this context, the focus of the research project is on brittle fracture. The goal is the establishment of a methodology to determine and assess dynamic fracture toughness values of DCI in the ductile-to-brittle transition regime, using samples extracted from a component. The experimental program uses a DCI material of grade GJS-400, which is generally used for transport and storage containers of radioactive materials. Firstly, a basic mechanical-technological material characterization will be performed consisting of tensile, Charpy and Pellini tests. Following the material characterization, the loading rate relevant for brittle fracture will be determined using instrumented C(T)25-fracture tests at a temperature of -40°C. To be able to transfer the relevant loading rate to other specimen geometries or sizes, the time-dependent course of the Weibull stress is assessed via numerical analyses. With this information an extensive experimental program consisting of DC(T)9, C(T)25, C(T)50, SE(B)10, SE(B)25 and SE(B)140 specimens is performed. These experimental results will be further supported by numerical and fractographic analyses. The empirical experimental database developed for DCI materials will be used to assess the applicability of the MC concept for DCI materials under dynamic loading. At the current time manufacturing and precracking of test specimens is ongoing. The authors provide first results concerning the mechanical-technological material characterization, the relevant loading rate for brittle fracture determined via C(T)25 tests, and some early results of other specimen types. These experimental results are also supported by preliminary numerical and statistical analyses. T2 - Conference SMiRT27 CY - Yokohama, Japan DA - 04.03.2024 KW - Dynamic fracture toughness KW - Ductile cast iron KW - ASTM E1921 KW - Master curve KW - Brittle fracture PY - 2024 AN - OPUS4-59859 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzwarth, Marcel A1 - Mayer, Uwe A1 - Baer, Wolfram A1 - Weihe, Stefan T1 - Investigation of the Master Curve Concept for Ferritic Ductile Cast Iron N2 - Within fracture mechanics safety assessment for steels in nuclear technology, the probabilistic master curve (MC) concept according to ASTM E1921 is currently used for quasi-static loading conditions as a supplement to the established deterministic ASME reference curve concept. However, for ductile cast iron (DCI), a systematic review of potential modifications to the assumptions and the procedure according to ASTM E1921 and an associated validation are still lacking. For this reason, the application of the fracture mechanics MC concept to ferritic ductile cast iron is being investigated in a joint research project between MPA Stuttgart and BAM Berlin. According to Hojo et al. (2008) the MC concept is already in use for the brittle fracture safety assessment of ferritic forged steel containers, which would suggest an extension to ductile cast iron containers. In compliance with IAEA SSG-26, the safety assessment of DCI containers for transport as well as storage of radioactive materials is based on the fracture mechanics criterion of general exclusion of crack initiation. Within this context, the focus of the current research project is on the further development of brittle fracture safety assessment methods. Therefore, a methodology shall be established to determine and assess dynamic fracture toughness values of DCI in the ductile-to-brittle transition regime, using only a low number of small fracture mechanics test specimens extracted from a component. For the experimental program, a DCI material of grade GJS-400 (GGG-40) has been produced as it is generally used for transport and storage containers for nuclear material. A basic mechanical-technological material characterization consisting of tensile, Charpy, and Pellini tests has been planned and a comprehensive fracture mechanics test program was compiled covering dynamic testing of DC(T)9, C(T)25, C(T)50, SE(B)10, SE(B)25, and SE(B)140 specimens at various loading rates and temperatures. The specimen testing is divided between the project partners based on specimen geometry. MPA Stuttgart has been tasked with the testing of the C(T), DC(T) and Pellini specimens, while BAM Berlin was assigned the SE(B), Charpy and tensile tests. These tests allow for the determination of the loading rate relevant for brittle fracture via C(T)25 specimens and an assessment of size effects by transferring the relevant loading rate to other specimen geometries and sizes. Numerical analyses of different specimen geometries and test setups are planned to investigate the influence of stress triaxiality and loading rate. Furthermore, the time-dependent course of the Weibull stress is assessed via these numerical analyses. Throughout the experimental program, the microstructure-property relationship will also be investigated based on quantitative metallographic and fractographic analyses like scanning electron microscope images and metallographic sections. With the acquired experimental database fundamental assumptions of the MC concept, like the weakest link model and the Weibull distribution, will be assessed for the application to DCI. In the end, the applicability of the MC concept will be evaluated and if necessary, modifications to the MC concept for DCI will be proposed. This paper will present the preliminary results of the GJS400 material characterization and the related selection of test specimen extraction points. First results of the C(T)25 and SE(B)140 specimen testing will also be discussed supported by first metallographic analyses. T2 - SMiRT27 Conference CY - Yokohama, Japan DA - 03.03.2024 KW - Ductile Cast iron KW - Dynamic Fracture Toughness KW - Safety Assessment KW - Master Curve Concept PY - 2024 SP - 1 EP - 10 AN - OPUS4-59302 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzwarth, Marcel A1 - Baer, Wolfram A1 - Mayer, Uwe A1 - Weihe, Stefan T1 - On the Applicability of the Master Curve Concept for Ductile Cast Iron based on experimental and microstructural results N2 - Based on the state-of-the-art research and regulations, the application of the fracture mechanics master curve (MC) concept to ferritic ductile cast iron (DCI) is being investigated in a joint research project (MCGUSS) between BAM Berlin and MPA Stuttgart. The experimental program included a basic mechanical-technological material characterization consisting of tensile, Charpy and Pellini tests. To determine the relevant loading rate for brittle fracture, instrumented C(T)25 fracture tests were performed at different loading rates at a temperature of -40°C. The relevant loading rates are 5x10^3 MPa√ms-1 and 5x10^4 MPa√ms-1. A series of dynamic fracture tests consisting of DC(T)9, C(T)25 and C(T)50 specimens were performed at MPA. BAM performed corresponding test series with SE(B)10 (pre-cracked Charpy), SE(B)25 and SE(B)140 specimens to cover the influence of specimen geometry. In total about 400 tests were performed during this project. The experimental program is complemented by extensive fractographic and metallographic studies using scanning electron microscopy and cross sectioning, as well as characterizations of the chemical composition of the material and of the morphology and distribution of the graphite particles. KJcd values were evaluated for all C(T)25 specimens and some C(T)50 and DC(T)9 specimens. First Master Curve analyses suggest that modifications on the Master Curve setup will be neccessary for instance changing the coefficient from 0.019 to 0.045. This modification requires further validation and is only one of many possible modifications. The SE(B) specimen results clearly show an inverse size effect. This does not correlate with the weakest link effect attributed to steels which dictates lower fracture toughness values for larger specimens. Due to the presence of graphite particles in the DCI material, it is currently assumed that these particles play a significant role in the failure behavior of DCI materials and the following fracture mechanism is proposed: “Specimen size-dependent arrest of local brittle fracures before global brittle failure by weakest link”. T2 - 9th SEDS Workshop: Safety of Extended Dry Storage, 20.-22. Mai 2025 CY - Garching, Germany DA - 20.05.2025 KW - Statistics KW - Dynamic fracture toughness KW - Ductile cast iron KW - Master curve KW - Safety assessment PY - 2025 SP - 1 EP - 3 AN - OPUS4-63566 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Castells-Gil, Javier A1 - Zhu, Jinjie A1 - Itskou, Ioanna A1 - Wolpert, Emma H. A1 - Hunter, Robert D. A1 - Tidey, Jeremiah P. A1 - Pedersen, Angus A1 - Solvay, Elisa A1 - Tyrrell, Helen A1 - Petit, Camille A1 - Barrio, Jesús T1 - Impact of N-heterocyclic amine modulators on the structure and thermal conversion of a zeolitic imidazole framework N2 - The zeolitic imidazole framework-8 (ZIF-8) is a crystalline porous material that has been widely employed as template to fabricate porous nitrogen-doped carbons with high microporosity via thermal treatment at high temperatures. The properties of the carbon scaffold are influenced by the pore structure and chemical composition of the parent ZIF. However, the narrow pore size distribution and microporous nature from ZIF-8 often results in low mesopore volume, which is crucial for applications such as energy storage and conversion. Here we show that insertion of N-heterocyclic amines can disrupt the structure of ZIF-8 and dramatically impact the chemical composition and pore structure of the nitrogen-doped carbon frameworks obtained after high-temperature pyrolysis. Melamine and 2,4,6-triaminopyrimidine were chosen to modify the ZIF-8 structure owing to their capability to both coordinate metal ions and establish supramolecular interactions. Employing a wide variety of physical characterization techniques we observed that melamine results in the formation of a mixed-phase material comprising ZIF-8, Zn(Ac)6(Mel)2 and crystallized melamine, while 2,4,6-triaminopyrimidine induces the formation of defects, altering the pore structure. Furthermore, the absence of heterocyclic amine in the ZIF-8 synthesis leads to a new crystalline phase, unreported to date. The thermal conversion of the modified ZIFs at 1000 °C leads to nitrogen-doped carbons bearing Zn moieties with increased surface area, mesopore volume and varying degree of defects compared to ZIF-8 derived carbon. This work therefore highlights both the versatility of heterocyclic amines to modify the structure of framework materials as well as their role in tuning pore structure in nitrogen-doped carbons, paving the way to targeted design of high-performance electrodes for energy storage and conversion. KW - Zeolitic imidazole framework KW - Heterocyclic amine KW - Triaminopyrimidine PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639177 DO - https://doi.org/10.1039/D5TA04831A SN - 2050-7488 SP - 1 EP - 13 PB - Royal Society of Chemistry (RSC) AN - OPUS4-63917 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Braga, Daniel S. A1 - Pedersen, Angus A1 - Riyaz, Mohd A1 - Barrio, Jesús A1 - Bagger, Alexander A1 - Neckel, Itamar T. A1 - Mariano, Thiago M. A1 - Winkler, Manuel E. G. A1 - Stephens, Ifan E. L. A1 - Titirici, Maria‐Magdalena A1 - Nagao, Raphael T1 - In situ structural evolution and activity descriptor of atomically dispersed catalysts during nitrate electroreduction N2 - Single‐Atom Catalysts (SAC) have emerged as a promising class of materials for various catalytic applications, including the electrochemical nitrate reduction reaction (eNO3RR) and consequently ammonia production. While the efficiency and selectivity of these materials have been extensively highlighted for the eNO3RR, the in situ evolution to their structure and composition during electrocatalysis is largely unexplored and lacks catalyst design principles. To solve this, we investigated a series of high utilization metal‐nitrogen‐carbon (MNC) SACs (M = Cr, Fe, Co, Ni, and Cu) for eNO3RR. Except for CuNC, which selectively produced nitrite, all catalysts exhibited Faradaic efficiencies (FE) for ammonia exceeding 50%. NiNC demonstrated the highest performance (FE of 78.0 ± 2.9% at −0.4 V versus reversible hydrogen electrode (RHE) at pH 13 and maximum ammonia production rate of 615.7 ± 176.5 µmol·h−1·, corresponding to an energy efficiency of 15.1 ± 1.4% at −0.6 VRHE), followed by CoNC. In situ Synchrotron X‐ray fluorescence (SXRF) mapping at various cathodic potentials (from open circuit potential to 0.0 VRHE and then −0.6 VRHE at 100 mV steps) revealed significant mobility of Ni within the carbon matrix, leading to the formation of metallic clusters from 0.0 VRHE. Similar in situ metal clustering is observed for CoNC. Structure‐activity plots are generated from both MNC literature and results obtained here, finding a clear trend between OH binding energy and turnover frequency, with the high activity of NiNC and CoNC in this work explained by their stronger OH binding in the metallic structure compared to their SAC coordination. This work therefore, reveals the structure‐activity‐stability of MNCs for eNO3RR and provides a simple descriptor for identifying highly active eNO3RR catalysts and their in situ structural evolution. KW - Single atom KW - Nitrate reduction KW - Structure-activity-selectivity KW - In situ PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640353 DO - https://doi.org/10.1002/advs.202510282 SN - 2198-3844 VL - 12 IS - 39 SP - 1 EP - 14 PB - Wiley-VCH CY - Weinheim AN - OPUS4-64035 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Butz, Adam T1 - Experimental and analytical investigation of notched components of a Nickel based superalloy under high temperature cyclic loading N2 - While the increase in use of renewable energy sources is a necessity in times of climate change the use of gas turbines as back-up requires them to be run in a much more flexible manner in order to compensate for side effects like sudden fluctuations of energy generation. The significant changes of stress and temperature levels in turbine blades due to start-up and shut down can cause crack initiation and growth in the blades‘ alloy. The aim of this research project is to identify a model for lifetime prediction for gas turbine components made of a Nickel base superalloy under high temperature with a Focus on stress concentration points such as cooling holes. T2 - HIDA-7 Conference on Life/Crack Assessment & Failures in Industrial Structures, UK CY - Portsmouth, UK DA - 15.05.2017 KW - LCF KW - Gas turbine KW - Service life model PY - 2017 AN - OPUS4-42274 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Morcillo, Dalia A1 - Winckelmann, Alexander A1 - Oelze, Marcus A1 - Leonhardt, Robert A1 - Schmidt, Anita A1 - Richter, Silke A1 - Recknagel, Sebastian A1 - Vogl, Jochen A1 - Panne, Ulrich A1 - Abad Andrade, Carlos Enrique T1 - Exploring Age-Induced Lithium Isotope Fractionation in Lithium-Ion Batteries using Microwave-Induced Cold Nitrogen Plasma Mass Spectrometry N2 - This study explores Microwave-Inductively Coupled Atmospheric-pressure Plasma Mass Spectrometry (MICAP-MS) as a cost-effective alternative to Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS) for analyzing lithium isotopic composition in lithium-ion batteries (LIBs). We investigate the performance of MICAP-MS in measuring Li isotope ratios in new and aged commercial lithium cobalt oxide (LCO) batteries. Our results show that MICAP-MS, operating under cold plasma conditions at 800 W with an 8 mm torch position, achieves results metrologically compatible with MC-ICP-MS, with a precision ranging from 0.6‰ to 3.4‰ for δ7Li values. MICAP-MS benefits from a dielectric resonator for uniform plasma, better ion velocity control, and higher energy efficiency. Optimal settings were identified with dwell times of 10 ms for 6Li and 1 ms for 7Li. The study of LIBs revealed that 6Li migrates towards the anode over multiple charge–discharge cycles, causing 7Li to accumulate in the cathode, a fractionation effect that becomes more pronounced with prolonged cycling. MICAP-MS provides a cost-effective, precise alternative to MC-ICP-MS, with lower operational costs and enhanced portability, advancing the study of isotopic fractionation and aging in lithium-ion batteries. KW - MICAP-MS KW - Lithium KW - Battery aging KW - Lithium isotopes KW - Nitrogen plasma KW - Isotope fractionation KW - lithium cobalt oxide KW - LCO PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643777 DO - https://doi.org/10.1039/d4ja00324a SN - 0267-9477 SP - 1 EP - 11 PB - Royal Society of Chemistry (RSC) AN - OPUS4-64377 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abad Andrade, Carlos Enrique T1 - Data-Driven Spectrochemical Sensing for Elemental and Isotopic Analysis—from Energy Systems to Biomedicine N2 - High-resolution optical spectrometers generate spectra containing tens of thousands of data points per sample. Picometre-scale isotope shifts, matrix-induced line broadening, and strong inter-feature correlations render classical peak fitting unreliable. Current analytical challenges, therefore, require rigorous algorithms able to expose latent structure, quantify uncertainty, and remain chemically interpretable. The research program presented in this lecture integrates state-of-the-art spectrochemical instrumentation with mathematically disciplined data models. Principal Component Analysis and Partial Least Squares provide chemically meaningful latent variables, while gradient-boosted decision trees or deep neural networks (ANNDL) capture residual non-linearity without sacrificing traceability. All models are trained on isotope-enriched or synthetically generated spectra and distributed with full validation workflows. Two research areas illustrate this strategy: (1) Isotopic analytics for materials, environment, and medicine. (2) Data-fusion diagnostics for battery ageing and failure. T2 - Temple University: Mechanical Engineering Transformative Science and Technology Engineering Lecture Series CY - Philadelphia, PA, USA DA - 02.10.2025 KW - Isotope KW - Data analysis KW - Machine learning KW - Elemental analysis KW - Battery PY - 2025 AN - OPUS4-64877 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abad Andrade, Carlos Enrique T1 - Tracking Lithium-Ion Battery Ageing via Lithium Isotope Fractionation N2 - Lithium-ion batteries power portable devices, electric vehicles, and stationary power grids, yet hidden aging reactions still shorten their service life and raise concerns about cost and safety. An analytical proxy is needed to report these reactions and accelerate product development, quality control, and recycling. Here, we demonstrate that subtle shifts in the natural 7Li/6Li ratio accurately record the two decisive stages of cell aging, solid-electrolyte interphase (SEI) formation and field-driven aging, which can be detected using multi-collector ICP-MS. Because Li is easily stripped from digested electrodes or electrolyte in a one-step cation-exchange column, high-purity solutions reach the spectrometer in minutes. A streamlined MC-ICP-MS run yields a δ7LiLSVEC precision of 0.4 ‰, enabling dozens of battery fractions to be analyzed per day. Applying the workflow to LiCoO2 coin cells as models, sampled from pristine to 700 cycles, reveals a clear isotopic narrative. During the first ≈45 cycles, 7Li leaves the LiCoO2 lattice, dissolves into the electrolyte, and is locked in the SEI on graphite, driving cathode δ7Li from +8 to –10 ‰ and raising the anode to +13 ‰ while capacity drops by 10 %. After the interphase matures, the electric field takes over: the lighter 6Li migrates faster to the anode, 7Li accumulates in the contracting Li1-xCoO2 lattice, and the bulk separation factor rises to α≈1.045 by 700 cycles. The δ7Li curve flattens roughly 70 cycles before capacity falls to 80%, providing an early warning of end-of-life. Isotopic gradients scale linearly with impedance growth, SEI thickness, and crack density confirmed by LA-ICP-MS mapping, FIB-SEM, XANES, and EXAFS. Although each data point requires one cell, lithium-isotope fractionation provides direct, element-specific, and structural fatigue insight unavailable from non-destructive tests. The straightforward chemistry and fast MC-ICP-MS routine make the approach practical for targeted aging studies, additive screening, and forensic autopsies, complementing high-throughput electrochemical methods and supporting the design of longer-lived batteries. T2 - SciX 2025 CY - Covington, KY, USA DA - 05.10.2025 KW - Isotope KW - Lithium KW - MC-ICP-MS KW - MICAP-MS KW - Isotope fractionation KW - Battery PY - 2025 AN - OPUS4-64879 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mesquita Silva da Veiga, Marcia T1 - Ultrasonic-assisted leaching of Li and Co from black mass using deep eutectic solvent N2 - The recovery of critical metals from spent lithium-ion batteries is a key strategy for sustainable resource management and the circular economy. Conventional hydrometallurgical processes typically rely on strong mineral acids and elevated temperatures, which, although effective, generate hazardous waste and demand high energy inputs. As a greener alternative, deep eutectic solvents (DES) combine low toxicity, non-volatility, simple synthesis, and tunable physicochemical properties, making them promising media for selective metal recovery1-2. Here, we report for the first time the use of ultrasound (US) to assist the leaching of Li and Co from LiCoO₂ black mass employing a deep eutectic solvent based on choline chloride and formic acid (ChCl:HCOOH, 1:2 molar ratio). The DES was synthesized at 90 °C for 3 h under stirring (300 rpm) and was characterized in terms of its molecular structure and formation by 1H-NMR and FT-IR, as well as by its viscosity and density. For each experiment, ~0.100 g of LiCoO2 was treated with 5 g of DES-FA in an ultrasonic bath (35 kHz, 60 °C) for different irradiation times (30–120 min), followed by three sequential extractions. All measurements were performed by ICP OES. Lithium solubilization reached ~80% at 90 min, while cobalt extraction was stabilizing at ~79% after 120 min. The enhanced performance under US is attributed to sonochemical effects that promote cavitation and microjets, leading to the disruption of particle agglomerates, the thinning of diffusion layers, and the generation of highly reactive local environments. These processes accelerate deintercalation and mass transfer within the solid–liquid interface. Combined with the mild acidity of DES-FA, which enables simultaneous leaching of both metals while favoring faster kinetics for Li, ultrasound provided a synergistic effect that enhanced the overall process and preserved the distinct extraction profiles of Li and Co. The extraction behavior of the two metals can be explained by their different speciation in the DES-FA medium. Cobalt is likely reduced from Co(III) to Co(II) by formic acid and stabilized through the formation of chloro-complexes such as [CoCl4]2- with chloride anions from ChCl, favoring its solubilization. In contrast, lithium does not form stable complexes with chloride under these conditions. It is primarily extracted as a solvated cation, stabilized by the extensive hydrogen-bond network of the DES. This difference accounts for the faster leaching kinetics observed for Li compared to Co. Selective recovery was achieved by pHcontrolled precipitation, with cobalt oxalate at pH 4-5 and lithium carbonate at pH 10. The Eco-Scale score of 85 confirmed the greenness of the method. This pioneering approach highlights the potential of coupling DES chemistry with ultrasound. Together, they represent a sustainable and efficient route for recovering critical metals from battery waste. T2 - 17th Rio Symposium on Atomic Spectrometry (17th RSAS) CY - São Pedro City, Brazil DA - 09.11.2025 KW - Black mass KW - deep eutectic solvent KW - Lithium KW - Cobalt KW - Lithium-ion battery recycling KW - Ultrasound-assisted extraction KW - Lithium and cobalt recovery KW - Green hydrometallurgy PY - 2025 AN - OPUS4-64956 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Askar, Enis T1 - Challenges for hydrogen technologies - Activities of H2Safety@BAM N2 - In this presentation the drivers for the rise of hydrogen technologies are outlined and main challenges for the market ramp-up are shown. Finally, the activities and capabilities of the competence center H2Safety@BAM are characterized and some of the current projects at BAM adressing the main challenges for hydrogen technologies are presented focussing on the hydrogen transport and infrastructure. T2 - Wasserstoff-Dialog - Stakeholder-Konferenz des Wasserstoff-Kompass CY - Berlin, Germany DA - 10.10.2022 KW - Hydrogen strategy KW - ModuH2Pipe KW - Hydrogen transport KW - Hydrogen infrastructure KW - Liquid hydrogen (LH2) PY - 2022 AN - OPUS4-57065 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grimault de Freitas, Tomás T1 - Comprehensive Standardisation of the Hollow Specimen Technique for Tests in High-Pressure Hydrogen Gas N2 - The hollow specimen technique is a simple and economical method that has the potential to overcome the limitations and complement the current techniques for qualifying metallic materials under highpressure hydrogen gas. In this technique, an axial hole is manufactured in a tensile specimen, which is then filled with hydrogen gas, sealed, and placed in a standard testing machine. This method requires significantly lower amounts of hydrogen, resulting in fewer safety measures and does not require complex equipment or a specialised laboratory, unlike the conventional autoclave technique. Initial studies have demonstrated the feasibility of assessing hydrogen effects in metallic materials using the hollow specimen technique. This led to the establishment of the committee ISO/TC 164/SC 1/WG 9 to standardise the method, however, there are still open questions that currently prevent the technique from being standardised for hydrogen testing. These open questions are being addressed in the H2HohlZug project, which is presented in this contribution. T2 - Oxford - EPRI Hydrogen Embrittlement Workshop CY - Oxford, United Kingdom DA - 23.06.2024 KW - Hollow Specimen Technique KW - High-pressure Gaseous Hydrogen KW - Hydrogen Embrittlement KW - Tensile Testing PY - 2024 AN - OPUS4-60501 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobol, Oded T1 - Hydrogen assisted cracking phenomena in duplex stainless steels elucidated by in- and ex-situ ToF-SIMS experiments N2 - In the presented research, the high potential and abilities of secondary ion mass spectrometry (ToF-SIMS) to detect and locally map the hydrogen distribution in two types of duplex stainless steels are shown. The research validates certain proposed mechanisms by combining ToF-SIMS with high-resolution scanning electron microscopy and electron-backscattered diffraction. The combination of data from several techniques on the same region was conducted in this field for the first time by applying data treatment of the ToF-SIMS raw data and data fusion approach. This powerful combination of methods allows reviewing of the occurring processes related to hydrogen assisted cracking. The step beyond the state of the art in this field was gained here by developing permeation and mechanical loading experiments within the ToF-SIMS during chemometric imaging of the hydrogen distribution in the microstructure. The research presents the necessary correlation between the hydrogen distribution and the resulted structural changes, the diffusion behavior in a duplex microstructure and stress induced diffusion of hydrogen by applying external load at the microscale. T2 - 6th WMRIF Early Career Scientist Summit CY - NPL Teddington UK DA - 18.06.2018 KW - ToF-SIMS KW - Duplex stainless steel KW - LDX KW - EBSD KW - Data-fusion PY - 2018 AN - OPUS4-46865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Junias, Josua Kondja T1 - Prediction of Explosion Characteristics of Hydrogen Mixtures Using Machine Learning Models N2 - An understanding of Hydrogen-Oxygen/Air-Diluents gas mixtures combustion characteristics and their accurate prediction is crucial for ensuring the safety of hydrogen-related applications, reducing accidents risk, and protecting lives and property. Hydrogen detonation propagations are characterized by the detonation cell size, used to quantitatively predict for a mixture to detonate including, among others, the initiation energy, critical and minimum tube diameters. For the prediction of explosion limits, detonation run-up-distances and cell sizes, various empirical, semi-empirical and numerical models can be found in literature. These models are usually limited to a narrow range of explosion process or geometrical experimental parameters. Moreover, based on the limited availability of the detonation cell widths measurements, current estimation models are seemingly inaccurate. Machine learning models can be utilized to make justifiable prediction on the detonation cell sizes of hydrogen-air mixtures and other gaseous explosive mixtures cell sizes, explosion limits or run-up distance to detonation based on the mixture type, temperature, pressure, equivalence ratios as well as on geometrical parameters with consideration of highly diverse experimental data measurements uncertainties. Therefore, an up-to date database for explosion characteristics will be established and machine learning models will be developed, trained, tested, and validated using experimental data to predict explosion characteristics of hydrogen mixtures. The models predicted results will be validated against existing models. It will be tested whether machine learning models are able to predict the explosion characteristics of hydrogen mixtures with better accuracy and more comprehensively than conventional empirical and numerical models to be found in literature. T2 - Combustion Institute 40th International Symposium CY - Milano, Italy DA - 21.07. 2024 KW - Prediction, detonation KW - Machine Learning KW - Flammability limits PY - 2024 AN - OPUS4-60769 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nietzke, Jonathan T1 - Evolution of tensile testing methodologies for hydrogen embrittlement in austenitic steels: a comparative study N2 - The energy transition towards hydrogen utilisation has increased the demand for reliable testing methods to evaluate the susceptibility of metallic materials to hydrogen degradation. However, traditional electrochemical pre-charging techniques have limitations in represent-ing realistic gaseous hydrogen exposure conditions. This study presents three comparative analyses of tensile testing methodologies, focusing on the differences between electrochem-ical pre-charging, gaseous pre-charging, and in-situ testing using hollow specimens for aus-tenitic steels AISI 304L and 316L type austenitic steels. Based on the results obtained, the first comparison reveals that electrochemically pre-charged and gaseously pre-charged specimens exhibit different behaviours regarding the impact on the mechanical properties. This effect can be retraced to the varying distribution of hydrogen throughout the specimens. Although comparable embrittlement was observed for similar hydrogen concentrations, the relationship appears to be non-systematic. The second comparison evaluates the performance of pre-charged hollow specimens (300°C, 100 bar, 21 days) in comparison to hollow specimens tested in-situ under 200 bar hydrogen during slow strain rate tensile tests (SSRT). While pre-charged specimens show a slight de-crease in elongation at fracture and a noticeable decrease in reduction of area (RA), in-situ tested specimens exhibit significantly more pronounced embrittlement. This is in accord-ance with the results of Michler et. al. In the third comparison, geometry effects between pre-charged conventional and pre-charged hollow specimens are explored. In this case, the hydrogen effect appears to be of the same order of magnitude for both specimen types, although some differences are ob-served. The study's findings underscore the importance of considering differences between test methods when assessing materials’ compatibility with hydrogen. It specifically emphasises the need for in-situ testing with gaseous hydrogen to better represent real conditions in ap-plications within the hydrogen sector. Furthermore, the study provides an initial compari-son between conventional and hollow specimens, demonstrating their capability to reveal hydrogen effects. However, additional research is essential to enhance the comparability of results yielded by these testing methods. T2 - European Conference on Fracture 2024 CY - Zagreb, Croatia DA - 26.08.2024 KW - Hollow Specimen Technique KW - Hydrogen KW - Austenitic Stainless Steel KW - Hydrogen Testing KW - AISI 316L PY - 2024 AN - OPUS4-60929 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nietzke, Jonathan T1 - The relationship between surface condition and the influence of hydrogen on the mechanical properties of additively manufactured 316L N2 - The following contribution presents the analyses of additively manufactured (AM) 316L using hollow specimens at 200 bar hydrogen and a strain rate of 1E-5 s-1. The work includes a comparison of three types of hollow specimens: mechanically extracted from fully additively manufactured cylinders, near-net-shape additively manufactured specimens, i.e. as printed, and specimens made of conventional 316L. AM specimens were manufactured via powder bed fusion with laser beam of metals (PBF-LB/M). For the near-net-shape specimens the inner hole remained without any mechanical processing. The inner holes of the cylindric specimens were manufactured by drilling with subsequent honing. The susceptibility to hydrogen embrittlement was found to be strongly dependent on the surface being in contact with hydrogen. While specimens with a clean surface had a relative reduction of area (RRA) of around 78 %, those with an as-printed surface showed a significantly larger RRA of around 90 %. One possible reason for this are oxide layers formed due to small amounts of oxygen during the AM-process. Further research is required to determine if the lower effect on the mechanical properties is permanently for as printed parts or e.g. time dependent. Additionally, further work with variation in the nominal strain rate is required. T2 - IIW 77th Annual Assembly 2024 CY - Rhodes, Greece DA - 07.07.2024 KW - Austenitic steel 316L KW - Additive manufacturing KW - PBF-LB/M KW - Hydrogen degradation KW - Hydrogen embrittlement KW - Hollow specimen technique PY - 2024 AN - OPUS4-60618 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nietzke, Jonathan T1 - Stainless Steels and Hydrogen Applications N2 - The contribution was presented at the Stainless Steel World Conference 2022. The presentation shows the influence of hydrogen on the mechanical properties of steel. Some test methods are shown and selected results are presented. T2 - Stainless Steel World Conference 2022 CY - Maastricht, Netherlands DA - 27.09.2022 KW - Gaseous hydrogen KW - Hydrogen Embrittlement KW - Hydrogen assisted cracking KW - SSRT PY - 2022 AN - OPUS4-55913 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grimault de Freitas, Tomás T1 - Hollow Specimen Technique for Tests in High-Pressure Hydrogen Gas: The Path Towards Standardisation and the Case Study of a Pipeline Steel and its Weld N2 - The hollow specimen technique is a simple method that has the potential to make material qualification with gaseous pressurized hydrogen widely applicable for the hydrogen industry at low cost. The feasibility of this method has been demonstrated in several studies, leading to the establishment of an ISO committee for its standardization. Questions have emerged during this process, that currently prevent the method from being standardized for hydrogen testing. These questions relate to specimen geometry, specimen manufacturing and gas quality and are being systematically addressed in the TransHyDE-H2HohlZug project. The aim is to close the identified gaps towards the standardization of this method for hydrogen testing. This contribution presents the structure and milestones of the project, followed by the results regarding the influence of specimen production and its response to hydrogen effects. Depending on the production method, different roughness and residual stresses can be expected on the inner hole surface of the specimens. This is of importance since an increase in stress concentration sites have been found to be associated to a higher severity of hydrogen effects. This influence has been investigated after applying the following machining processes: a) drilled only; b) drilled and reamed; c) drilled and honed; d) electro-discharge machining (EDM) and honed; e) EDM and reamed. Roughness measurements using a profilometer, electron back-scatter diffraction (EBSD) analysis and microhardness tests have been performed previous to mechanical testing to infer on the effect of the different production methods on the surface of the inner hole. Next, the specimens were mechanically tested via slow strain rate tensile tests in a argon and in hydrogen, both at 150 bar and room temperature. Here, a strain-rate sensibility analysis was also performed to identify an optimal strain-rate for the mechanical tests. Based on the results an optimal production method is identified and proposed. T2 - ASTM Conference on Hydrogen Materials CY - La Rochelle, France DA - 03.06.2025 KW - Hydrogen KW - Hydrogen Embrittlement KW - Hollow Specimen Technique KW - High-Pressure Gaseous Hydrogen KW - Austenitic Stainless Steel KW - H2HohlZug KW - TransHyDE KW - Tensile Test KW - Pipeline Steel PY - 2025 AN - OPUS4-63329 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobol, Oded T1 - Challenges with metallic materials in hydrogen technologies N2 - The contribution was presented in the Joint European Summer School in Athens as part of several contributions from BAM in the field of hydrogen safety. These presentations are given in order to provide an overview about the activities of BAM as part of the competence center H2Safety@BAM T2 - JOINT EUROPEAN SUMMER SCHOOL (JESS) CY - Athens, Greece DA - 12.09.2022 KW - Gaseous hydrogen KW - Hydrogen Embrittlement KW - Hydrogen assisted cracking PY - 2022 AN - OPUS4-55822 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Battistella, Beatrice T1 - Isotopic Fractionation in Lithium-Ion Batteries (LIBs): A New Key to Understand Degradation N2 - The presentation summarizes the research work of division 1.6 on Li isotope fractionation in Li-ion batteries (LIB). This work interrogates whether changes in Li isotopic distribution in LIB components can be used as a diagnostic tool to monitor interphases growth at the electrodes surfaces and as a benchmark to track battery degradation. For this purpose, different analytical techniques have been employed to study the electrodes of commercial and lab-scale cells, providing bulk (MC-ICP-MS) and local (GD-MS, LA-ICP-MS) information about the Li isotope distribution changes upon cells cycle aging. The results show Li isotope fractionation in full Li ion cells upon aging, suggesting that the 6Li accumulation on the surface of the negative electrode might be used as a new benchmark to track the solid electrolyte interphase growth T2 - ADLERSHOFER KOLLOQUIUM Analytik – Abteilung 1 CY - Berlin, Germany DA - 28.10.2025 KW - MC-ICP-MS KW - Li-ion Batteries KW - Li Isotopes KW - LA-ICP-MS KW - GD-MS PY - 2025 AN - OPUS4-64511 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander A1 - Schukar, Marcus A1 - Breithaupt, Mathias A1 - Kriegsmann, Andreas T1 - Distributed Fibre Optic Monitoring of Hydrogen Storage Composite Pressure Vessels for Automotive Use N2 - We present our research work on the condition monitoring of hydrogen storage composite pressure vessels using distributed fibre optic sensors. The sensing fibres are integrated into the composite structure by wrapping them over the polymer liner in the helical and circumferential direction during the manufacturing process of the carbon fibre reinforced polymer. The following use of optical backscatter reflectometry allows for continuous condition monitoring and precise detection and localization of structural damages during the entire service life. To account for the time-dependent strength degradation of the composite pressure vessels, both slow burst and ambient hydraulic cycling tests, respectively, were conducted on five 70 MPa pressure vessels with integrated fibre optic sensors. The results achieved via distributed fibre optic strain sensing demonstrate a near linear strain response to pressure suitable for sensitive condition monitoring and confirm the required robustness of the selected sensor solution. T2 - DGZfP-Jahrestagung 2025 CY - Berlin, Germany DA - 26.05.2025 KW - Distributed fibre optic sensor (DFOS) KW - Composite pressure vessel KW - Optical backscatter reflectometry KW - Slow burst test KW - Ambient hydraulic cycling test PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653067 DO - https://doi.org/10.58286/32344 SP - 1 EP - 8 PB - NDT.net AN - OPUS4-65306 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. A1 - Becker, Ben A1 - Duffner, Eric A1 - John, Sebastian T1 - Storage systems for CGH2- systematic improvement of RC&s composite storage systems for compressed hydrogen - systematic improvement of regulations for more attractive storage units N2 - Hydrogen is an attractive energy carrier that requires high effort for safe storage. For ensuring safety they have to undergo a challenging approval process. Relevant standards and regulations for composite cylinders used for the transport of for on-board storage of hydrogen are currently based on deterministic (e.g. ISO 11119-3) or semi-probabilistic (UN GTR No. 13) criteria. This paper analysis the properties of such methods in regards to the evaluation of load cycle strength. Their characteristics are compared with the probabilistic approach of the BAM. Based on Monte-Carlo simulations, the available design range (mean value and scatter of strength criteria) of current concepts were exemplarily estimated. The aspect of small sample sizes is analysed and discussed with respect to the evaluation procedures. T2 - 10th International Conference on Sustainable Energy and Environmental Protection CY - Bled, Slovenia DA - 27.06.2017 KW - Probabilistic KW - Hydrogen KW - Composite KW - Cylinder KW - Regulations KW - Load cycles KW - GTR 13 KW - ISO 11119 PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-416820 SN - 978-961-286-054-7 DO - https://doi.org/10.18690/978-961-286-054-7 SP - 1 EP - 10 PB - University of Maribor Press CY - Maribor, Slovenia AN - OPUS4-41682 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Olejko, Lydia A1 - Bald, Ilko T1 - FRET efficiency and antenna effect in multi-color DNA origami-based light harvesting systems N2 - Artificial light harvesting complexes find applications in artificial photosynthesis, photovoltaics and light harvesting chemical sensors. They are used to enhance the absorption of light of a reaction center which is often represented by a single acceptor. Here, we present different light harvesting systems on DNA origami structures and analyze systematically the light harvesting efficiency. By changing the number and arrangement of different fluorophores (FAM as donor, Cy3 as transmitter and Cy5 as acceptor molecules) the light harvesting efficiency is optimized to create a broadband absorption and to improve the antenna effect 1 (including two energy transfer steps) from 0.02 to 1.58, and the antenna effect 2 (including a single energy transfer step) from 0.04 to 8.7, i.e. the fluorescence emission of the acceptor is significantly higher when the light-harvesting antenna is excited at lower wavelength compared to direct excitation of the acceptor. The channeling of photo energy to the acceptor proceeds by Förster Resonance Energy Transfer (FRET) and we carefully analyze also the FRET efficiency of the different light harvesting systems. Accordingly, the antenna effect can be tuned by modifying the stoichiometry of donor, transmitter and acceptor dyes, whereas the FRET efficiency is mainly governed by the spectroscopic properties of dyes and their distances. KW - DNA origami KW - Light-harvesting KW - FRET KW - Antenna effect PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-405867 UR - http://pubs.rsc.org/en/content/articlelanding/2017/ra/c7ra02114c#!divAbstract DO - https://doi.org/10.1039/C7RA02114C VL - 7 IS - 39 SP - 23924 EP - 23934 PB - The Royal Soc. of Chemistry AN - OPUS4-40586 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Schneider, Ronald T1 - Time-variant reliability of deteriorating structural systems conditional on inspection and monitoring data N2 - The current practice of operating and maintaining deteriorating structural systems ensures acceptable levels of structural reliability, but it is not clear how efficient it is. Changing the current prescriptive approach to a risk-based approach has great potential to enable a more efficient management of such systems. Risk-based optimization of operation and maintenance strategies identifies the strategy that optimally balances the cost for controlling deterioration in a structural system with the achieved risk reduction. Inspections and monitoring are essential parts of operation and maintenance strategies. They are typically performed to reduce the uncertainty in the structural condition and inform decisions on future operation and maintenance actions. In risk-based optimization of operation and maintenance strategies, Bayesian updating is used to include information contained in inspection and monitoring data in the prediction of the structural reliability. All computations need to be repeated many times for different potential inspection and monitoring outcomes. This motivates the development of robust and efficient approaches to this computationally challenging task. The reliability of deteriorating structural systems is time-variant because the loads on them and their capacities change with time. In most practical applications, the reliability analysis of deteriorating structural systems can be approached by dividing their lifetime into discrete time intervals. The time-variant reliability problem can then be represented by a series of time-invariant reliability problems. Using this methodology as a starting point, this thesis proposes a novel approach to compute the time-variant reliability of deteriorating structural systems for which inspection and monitoring data are available. The problem is formulated in a nested way in which the prediction of the structural condition is separated from the computation of the structural reliability conditional on the structural condition. Information on the structural condition provided by inspections and monitoring is included in the reliability assessment through Bayesian updating of the system deterioration model employed to predict the structural condition. The updated system reliability is obtained by coupling the updated deterioration model with a probabilistic structural model utilized to calculate the failure probability conditional on the structural condition. This approach is the first main outcome of this thesis and termed nested reliability analysis (NRA) approach. It is demonstrated in two numerical examples considering inspected and monitored steel structures subject to high-cycle fatigue. An alternative – recently developed – approach, which also follows the strategy of discretizing time, describes deteriorating structural systems with hierarchical dynamic Bayesian networks (DBN). DBN combined with approximate or exact inference algorithms also enable the computation of the time-variant reliability of deteriorating structural systems conditional on information provided by inspection and monitoring data. In this thesis – as a proof of concept – a software prototype is developed based on the DBN approach, which can be used to assess the reliability of a corroding concrete box girder for which half-cell potential measurements are available. This is the second main outcome of this thesis. Both approaches presented in this thesis enable an integral reliability analysis of inspected and monitored structures that accounts for system effects arising from (a) the correlation among deterioration states of different structural elements, (b) the interaction between element deterioration and system failure, and (c) the indirect information gained on the condition of all unobserved structural elements from inspecting or monitoring the condition of some structural elements. Thus, both approaches enable a systemwide risk-based optimization of operation and maintenance strategies for deteriorating structural systems. The NRA approach can be implemented relatively easily with subset simulation, which is a sequential Monte Carlo method suitable for estimating rare event probabilities. Subset simulation is robust and considerably more efficient than crude Monte Carlo simulation. It is, however, still sampling-based and its efficiency is thus a function of the number of inspection and monitoring outcomes, as well as the value of the simulated event probabilities. The current implementation of the NRA approach performs separate subset simulation runs to estimate the reliability at different points in time. The efficiency of the NRA approach with subset simulation can be significantly improved by exploiting the fact that failure events in different years are nested. The lifetime reliability of deteriorating structural systems can thus be computed in reverse chronological order in a single subset simulation run. The implementation of the DBN approach is much more demanding than the implementation of the NRA approach but it has two main advantages. Firstly, the graphical format of the DBN facilitates the presentation of the model and the underlying assumptions to stakeholders who are not experts in reliability analysis. Secondly, it can be combined with exact inference algorithms. In this case, its efficiency neither depends on the number of inspection and monitoring outcomes, nor on the value of the event probabilities to be calculated. However, in contrast to the NRA approach with subset simulation, the DBN approach with exact inference imposes restrictions on the number of random variables and the dependence structure that can be implemented in the model. T3 - BAM Dissertationsreihe - 168 KW - Reliability KW - Structural systems KW - Deterioration KW - Bayesian analysis KW - Inspection KW - Monitoring KW - Zuverlässigkeit KW - Tragstrukturen KW - Schädigungsprozesse KW - Bayes'sche Analyse KW - Inspektion KW - Monitoring PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512977 SN - 1613-4249 VL - 168 SP - 1 EP - 188 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-51297 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -