TY - CONF A1 - Gottschalk, Götz-Friedrich A1 - Chaurasia, Prashant Kumar A1 - Goecke, Sven-Frithjof T1 - Zero-defect Printing with DED-GMA via Adaptive Controls N2 - Gas metal arc assisted directed energy deposition (DED-GMA) is a metal additive manufacturing process for fabricating large-scale parts with a higher printing rate. An accurate monitoring and control of the melt pool geometric features is critical for printing zero-defect parts. In this study, the melt pool thermography is used for the real-time detection of the melt pool boundary, centreline, and transient cooling time using an efficient deep learning technique. The presented real-time process monitoring and control methodology using deep learning allows adaptive control of the DED-GMA process. T2 - Twenty-Second International Conference on Flow Dynamics (ICFD 2025) CY - Sendai, Japan DA - 10.11.2025 KW - Additive manufacturing KW - DED-Arc KW - Monitoring KW - Control PY - 2025 SP - 1332 EP - 1335 AN - OPUS4-64837 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Neugum, Tim A1 - Stelzner, Ludwig A1 - Häßler, Dustin A1 - Zehfuß, Jochen A1 - Hothan, Sascha T1 - Application of the substructure method to assess the fire resistance of thermally restrained columns N2 - Usually, the fire resistance of load-bearing structural elements is determined by single members testing. A mechanical load is applied to the member in a force-controlled manner and is maintained constant throughout the fire test. After applying the mechanical load, the thermal exposure starts according to the ISO 834 fire curve. In this conventional test method, no interaction between the tested member and the entire building structure is considered. In buildings, the surrounding structure can restrain the thermal expansion of a member in case of fire. This may have both positive and negative effects on the fire resistance of this structural element. Several years ago, the Institute for Sustainability and Innovation in Structural Engineering (ISISE) at the University of Coimbra in Portugal and the Bundesanstalt für Materialforschung und prüfung (BAM) in Germany carried out fire tests on circular and square steel-reinforced concrete columns with restrained thermal expansion. BAM´s column test furnace allows the specimen to be subjected to thermal exposure and mechanical loading simultaneously. In addition, this device has a substructure test module, which can also provide restrained test conditions. In an ongoing research project at BAM and Technische Universität Braunschweig, the effect of restrained test conditions on the behaviour of steel-reinforced columns under fire exposure is further investigated. T2 - 8th International RILEM Workshop on Concrete Behaviour due to Fire Exposure CY - Krakow, Poland DA - 18.09.2025 KW - Substructure method KW - Surrounding structure KW - Fire resistance KW - Restrained columns KW - Concrete PY - 2025 SP - 1 EP - 2 AN - OPUS4-64582 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Winkler, Nicolas P. A1 - Neumann, Patrick P. A1 - Schaffernicht, E. A1 - Lilienthal, A. J. T1 - Heterogeneous Sensor Networks: Challenges and Insights from an Industrial Scenario N2 - Monitoring airborne pollutants is critical for occupational health, particularly in industrial environments where workers are exposed to hazardous emissions. Traditional measurements are typically limited to single-day campaigns, resulting in extremely sparse temporal data. Low-cost sensor networks offer a way to increase spatial and temporal resolution but are limited by issues of accuracy and reliability. To address this, we present a wireless heterogeneous sensor network that integrates low-cost stationary nodes with high-quality sensors on mobile platforms, including ground and aerial robots. We deploy this system in a hot rolling mill facility and evaluate its performance under real-world conditions. Field experiments reveal dynamic pollutant patterns, such as altitude-dependent PM2.5 gradients and temperature fluctuations. By introducing synchronized “rendezvous” events between mobile and stationary nodes, we demonstrate correlation capabilities of sensors. Our spatiotemporal analysis shows that, despite limitations of mobile sensing, strategically combining heterogeneous data sources enables capturing pollutant dynamics in complex industrial settings. T2 - IEEE SENSORS 2025 CY - Vancouver, BC, Kanada DA - 19.10.2025 KW - Environmental monitoring KW - Sensor data fusion KW - Sensor system networks KW - Mobile robotics PY - 2025 SN - 979-8-3315-4467-6 SP - 1 EP - 4 PB - IEEE CY - Piscataway, NJ, USA AN - OPUS4-64501 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Ahmadzadeh, Majid A1 - Weise, Matthias T1 - Air-coupled ultrasonic transmission using thermoacoustic transmitters and optical microphones N2 - Background, Motivation and Objective Air-coupled ultrasonic transducers are usually applied for testing of some lightweight components. To increase the bandwidth or air-coupled testing systems and thus increase their application range, thermoacoustic transducers can be paired with optical microphones in a transmission mode. Thermoacoustic transmitters are based on the thermal excitation of sound waves, while optical microphones are based on laser interferometry and Fabri-Pérot etalon. We studied the spectrum and the efficiency of the transmission of an air gap using a thermoacoustic transmitter and an optical microphone. Statement of Contribution/Methods Thermoacoustic transmitters with an electrically conductive layer of indium tin oxide (ITO) on a curved quartz glass substrate were developed. Their sound field was measured using a commercially available optical microphone Eta450 Ultra based on Fabri-Perot etalon. The curvature and the conductive layer thickness of the thermoacoustic transmitter were systematically varied to investigate their impact on the sound field and the spectrum of the measured signal for frequencies up to 1 MHz. The transmitters were excited using rectangular burst signals with a varied width. We examined the influence of all parameters on the focusing, spectrum, and sensitivity. The directivity of the microphone was evaluated as well. Results/Discussion The focusing of the sound fields of all transmitters most strongly depends on the curvature radius of the substrate. The spectrum recorded in the focus of each transducer has several maxima and minima, as shown in the left-hand diagram, which are mostly a consequence of the irregularities of the microphone spectrum. These irregularities are visible also in the directivity diagram on the right, which was recorded by rotating the microphone. The 20 dB bandwidth of the measurement system covers the range up to about 1 MHz, depending strongly on the width of the excitation pulse (left-hand diagram). This highlights a key advantage of thermoacoustic transmitters: their spectral characteristics can be controlled through the excitation conditions, offering a potentially broader range of applications compared to conventional air-coupled transmitters. One promising example is localized ultrasound spectroscopy based on the detection of local resonances. T2 - IEEE International Ultrasonic Symposium CY - Utrecht, The Netherlands DA - 15.09.2025 KW - Air-coupled ultrasound KW - Thermoacoustic transmitter KW - Sound field PY - 2025 SP - 1 EP - 4 AN - OPUS4-64541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - George, Joyal K. A1 - von Wangenheim, Kristian A1 - Kaplan, Felix A1 - Schneider, Ronald A1 - Hindersmann, Iris ED - Lienhart, Werner ED - Krüger, Markus T1 - Monitoring of civil engineering structures - current and future use cases N2 - Monitoring represents an effective approach for addressing the diverse challenges associated with the maintenance of civil engineering structures. It contributes to improving both the availability and safety of these structures. By increasing the amount of information available about the structure, monitoring supports better-informed decisions regarding its preservation. Due to the complexity of monitoring applications, specific use cases are outlined. A key advantage of these use cases is that new technologies can be tested within well-defined and limited scopes. The use cases monitoring of known, localized damage, monitoring of known deficits identified through reassessment or resulting from outdated design procedures and monitoring aimed at assessing traffic loads and their effects currently account for the majority of implemented monitoring measures. Their practical implementation is demonstrated through case studies from the Brandenburg State Road Authority. Additional use cases, such as monitoring to support structural inspections and monitoring of major structures, such as large viaducts, are gaining importance, with initial practical examples already present in Europe. Future applications reveal potential for expanded use, particularly in the context of monitoring to support predictive lifecycle management. This will become increasingly important in the implementation of digital twins, as announced in the national BIM master plan. Furthermore the concept of a Birth Certificate is intended to establish a reference state of the structure prior to commissioning, which can then be used for comparison with future measurements over time. The integration and interaction of these individual use cases pave the way for the implementation of digital twins. T2 - 13th International Conference on Structural Health Monitoring of Intelligent Infrastructure CY - Graz, Austria DA - 01.09.2025 KW - Structural Health Monitoring KW - Use Cases KW - Bridges KW - Digital Twin PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644422 DO - https://doi.org/10.3217/978-3-99161-057-1-033 SP - 203 EP - 208 PB - Verlag der Technischen Universität Graz CY - Graz AN - OPUS4-64442 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Neugum, Tim A1 - Stelzner, Ludwig A1 - Häßler, Dustin A1 - Zehfuß, Jochen A1 - Hothan, Sascha T1 - Berücksichtigung der Tragwerksumgebung bei Brandversuchen an Stahlbetonstützen N2 - Das Tragwerk eines Gebäudes ist aus einzelnen Bauteilen zusammengesetzt. Insbesondere bei lokalen Brandereignissen bauen sich durch die Ausdehnung der vom Brand betroffenen Bauteile gegen das umgebende kältere Gesamttragwerk Zwangsbeanspruchungen auf. Bei konventionellen Brandprüfungen werden diese Zwangsbeanspruchungen in der Regel nicht berücksichtigt, da die Prüfsystematik auf Einzelbauteilprüfungen bei konstanter mechanischer Last ausgelegt ist. Die Prüfung komplexer, realmaßstäblicher Tragwerke ist oftmals nicht möglich. Die Interaktion des Einzelbauteils mit dem umgebenden Tragwerk kann sich sowohl positiv als auch negativ auf den Feuerwiderstand auswirken. Als nachteilig ist der thermische Zwang und die daraus resultierende Lasterhöhung zu nennen. Gleichzeitig kann eine Stauchung der Stütze zu einer Umlagerung von Kräften in das umgebende Tragwerk führen und damit den Versagenszeitpunkt der Stütze verzögern. Mit Hilfe der Substrukturtechnik kann das Verhalten einer Stütze im Brandfall unter Berücksichtigung der Interaktion mit dem umgebenden Tragwerk analysiert werden. In einem gemeinsamen DFG-Vorhaben der Bundesanstalt für Materialforschung und -prüfung (BAM) und dem Institut für Baustoffe, Massivbau und Brandschutz (iBMB) der TU Braunschweig werden 14 Stahlbetonstützen mit freier und behinderter axialer Ausdehnung untersucht. Auf Basis eines realen Gebäudes werden unter anderem die Steifigkeit, welche das umgebende Tragwerk repräsentiert, der Lastausnutzungsgrad und die Brandeinwirkung variiert. Mit dem Ziel das Stützenverhalten unter thermischem Zwang im Detail zu analysieren, erfolgen Brandversuche und numerische Simulationsberechnungen. Dabei werden die erforderlichen mechanischen Materialeigenschaften des Betons bei erhöhten Temperaturen aus experimentellen Daten abgeleitet. Der Beitrag liefert einen Einblick in die experimentellen und numerischen Ergebnisse. Es zeigt sich, dass die behinderte axiale Ausdehnung und die Möglichkeit einer Lastumlagerung bei Stauchung der Stütze einen erheblichen Einfluss auf das Versagen im Brandfall haben. Die mittels Substrukturtechnik erzeugte Zwängung des umgebenden Tagwerks führt zu einem Anstieg der Axialkraft in der Stütze sowie einer Abnahme der maximalen Stützenausdehnung. Gleichzeitig setzt die Stauchung der Stütze früher ein. Wird eine Stütze-Tragwerk-Interaktion auch für den Stauchungsbereich der Stütze angesetzt, kann der Vorteil einer Lastumlagerung genutzt werden. Somit kann trotz einer höheren mechanischen Belastung während der Ausdehnungsphase der Stütze ein späterer Versagenszeitpunkt als bei einer konventionell geprüften Stütze erreicht werden. T2 - Symposiums Heißbemessung – Structural Fire Engineering 2025 CY - Braunschweig, Germany DA - 29.09.2025 KW - Substrukturtechnik KW - Stahlbetonstützen KW - Feuerwiderstand KW - Stützenbrandversuche KW - Numerik PY - 2025 SP - 38 EP - 52 PB - TU Braunschweig AN - OPUS4-64581 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lehmann Schlag, Jens A1 - Burkert, Andreas A1 - Köstermann, U. T1 - Einsatz von Duplexstählen in Straßentunneln: Verbesserung der Sicherheit und Dauerhaftigkeit N2 - Die vorgestellten Ergebnisse eines gemeinsamen Forschungsvorhabens der BAM, Straßen.NRW, LSBG, ISER und weiteren Partnern zeigen geeignete Duplexstähle für die Betriebs- und Sicherheitsausstattung in Straßentunneln, die in einer Parameterstudie in mehreren Straßentunneln umfassend untersucht worden sind. Spaltkorrosion war dabei die maßgebliche Korrosionsart und wurde als Bewertungskriterium herangezogen. Die Werkstoffgruppe CRC III mit einem PRE(N)-Wert von 24 bis 27 zeigte in den Untersuchungen eine nur ungenügende Spaltkorrosionsbeständigkeit. Das für die Wahrscheinlichkeit der Spaltkorrosionsbeständigkeit anzustrebende 95 %-Quantil wird erst bei PRE(N) > 34 erreicht. Die Erkenntnisse aus der Parameterstudie wurden in einem Pilotprojekt von Straßen.NRW umgesetzt, bei dem unter anderem Strahlventilatoren vollständig aus Duplexstahl 1.4462 gefertigt worden sind. Dadurch soll eine Nutzungsdauer von mindestens 35 Jahren sichergestellt werden. T2 - STUVA Tagung 2025 CY - Hamburg, Germany DA - 25.11.2025 KW - Korrosion KW - Tunnel KW - Atmosphärische Korrosion KW - Nichtrostender Stahl KW - Auslagerung PY - 2025 SN - 978-3-96892-327-7 VL - 61 SP - 335 EP - 340 PB - Studiengesellschaft für Tunnel und Verkehrsanlagen e.V. STUVA CY - Köln AN - OPUS4-64983 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schackmann, Oliver A1 - Márquez Reyes, Octavio A1 - Memmolo, Vittorio A1 - Lozano, Daniel A1 - Prager, Jens A1 - Moll, Jochen A1 - Kraemer, Peter T1 - Intelligent damage detection in composite pressure vessels under varying environmental and operational conditions N2 - Despite proven approaches available in the literature, structural health monitoring by ultrasonic guided waves under varying environmental and operational conditions is still challenging. The use of machine learning approaches is discussed in this work, considering the complex problem of experimental damage detection under varying load conditions in a composite overwrapped pressure vessel for hydrogen storage. Specifically, unsupervised methods originally developed for image and time series classification are combined with ensemble voting to conceive reliable damage detection technique. This enables the effective combination of the predictions of multiple transducer pairs, even with a limited number of strong individual classifiers. A performance demonstration of the technique is presented using a real damage scenario dataset. T2 - IEEE 12th International Workshop on Metrology for AeroSpace (MetroAeroSpace) CY - Napoli, Italy DA - 18.06.2025 KW - Guided ultrasonic waves KW - Structural health monitoring KW - Artificial intelligence KW - Hydrogen storage PY - 2025 SN - 979-8-3315-0152-5 DO - https://doi.org/10.1109/MetroAeroSpace64938.2025.11114628 SN - 2575-7490 SP - 608 EP - 613 AN - OPUS4-64894 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Eiz Eddin, Ahmad A1 - Stelzner, Ludwig A1 - Häßler, Dustin A1 - Hothan, Sascha T1 - Tragfähigkeit und Abplatzverhalten von Carbonbeton bei hohen Temperaturen N2 - Zur Bewertung der Biegetragfähigkeit dünnwandiger, carbonbewehrter Betonbauteile unter Temperatureinfluss wurden 4-Punkt-Biegeversuche in drei thermischen Konfigurationen durchgeführt. Die Ergebnisse zeigen, dass bei Raumtemperatur kein signifikanter Einfluss der Vorspannung auf die Bruchkraft vorliegt. Mit steigender Temperatur nimmt die Biegetragfähigkeit infolge des Festigkeitsverlustes von Beton und Carbonbewehrung sowie durch das Schmelzen der Tränkungsmatrix deutlich ab. Zwei Versagensmechanismen konnten identifiziert werden, d.h. Zugversagen bei hoher Vorspannung und Verbundversagen bei niedriger Vorspannung. Die Abnahme der Verbundfestigkeit ist auf das Erweichen der Tränkungsmatrix bei Überschreitung der Glasübergangstemperatur zurückzuführen. Bei Temperaturen oberhalb von etwa 200 °C ist keine Tränkungsmatrix und daraus resultierende Verbundwirkung mehr vorhanden. Darüber hinaus wurden im Rahmen von Abplatzversuchen drei Schutzmaßnahmen zur Vermeidung von Betonabplatzungen im Brandfall untersucht, d.h. reaktives Brandschutzsystem (RBS), zementgebundene Brandschutzplatten sowie Zugabe von Polypropylenfasern (PP-Fasern) zur Betonmischung. Die Ergebnisse zeigen, dass der Typ des Carbongeleges die Wirksamkeit der Schutzmaßnahmen beinflusst. Während die Zugabe von PP-Fasern das Abplatzen bei beiden untersuchten Gelegetypen verhindern konnte, war dies bei RBS und Brandschutzplatten nur bei einem Gelegetyp erfolgreich. Die Ursache der Abplatzungen ist auf das temperaturbedingte Schmelzen und die damit einhergehende Volumenzunahme der im Gelege Q85 vorhandenen Hilfsfäden zurückzuführen. Dies führt zu einer Rissbildung parallel zur brandbeanspruchten Betonoberfläche. Der Dampfdruck im Beton ist trotz reduzierter Erwärmungsgeschwindigkeit zu hoch, weshalb es zum Abplatzen kommt. Im Gegensatz dazu bewirkt das Schmelzen der PP-Fasern eine Erhöhung der Permeabilität des Betons. Dadurch kann der entstehende Wasserdampf frühzeitig entweichen, sodass der Dampfdruck unterhalb der kritischen Schwelle bleibt, die für das Abplatzen erforderlich wäre. T2 - Symposium Heißbemessung 2025 CY - Braunschweig, Germany DA - 29.09.2025 KW - Carbonbeton KW - Biegetragfähigkeit KW - Abplatzverhalten PY - 2025 SP - 1 EP - 13 PB - Institut für Baustoffe, Massivbau und Brandschutz (iBMB), Technische Universität Braunschweig CY - Braunschweig, Deutschland AN - OPUS4-64882 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Neumann, Patrick P. A1 - Winkler, Nicolas P. A1 - Nerger, Tino A1 - Lohrke, Heiko A1 - Bartholmai, Matthias T1 - Robotic Olfaction in Action: Field Applications and Results from Current Research N2 - In recent decades, robotics, particularly in environmental monitoring, has made significant advances. Robots of various forms and sizes have become essential tools for data collection in environmental research. Mobile Robot Olfaction (MRO) involves mobile robots equipped with gas sensors and requires the integration of multiple disciplines, including signal processing, machine perception, autonomous navigation, and pattern recognition. Common applications of MRO include mapping gas distributions, locating and detecting gas sources, and tracking gas plumes. Aerial Robot Olfaction (ARO) is a specialized branch of MRO that adapts these concepts to aerial robots, addressing the challenges of airborne gas sensing. This presentation highlights recent developments and results from ongoing research projects in MRO and ARO, with a focus on real-world deployment scenarios and the challenges encountered in practice. T2 - Drohnen in der Zerstörungsfreien Prüfung CY - Magdeburg, Germany DA - 26.11.2025 KW - Ground and Aerial robots KW - Gas distribution mapping KW - Gas source localization KW - Gas Tomography KW - Mobile Robotic Olfaction PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648928 UR - https://www.ndt.net SP - 1 EP - 15 PB - DGZfP AN - OPUS4-64892 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hille, Falk A1 - Schneider, Ronald A1 - Simon, Patrick A1 - Herrmann, Ralf A1 - Baeßler, Matthias ED - Döhler, Michael ED - Mélot, Adrien ED - Aenlle Lopez, Manuel T1 - System identification and model calibration of a steel road bridge N2 - The Bundesanstalt für Materialforschung und -prüfung (BAM), in cooperation with the Netherlands Organization for Applied Scientific Research (TNO), is working on a framework for integrating frequently updated structural models into an asset management process for bridge structures. A multi-span steel road bridge was selected as a test case for the development of this framework. In order for the structural model to represent the real behavior of the bridge with sufficient accuracy, model calibration is required. In this case, we have planned to calibrate the model based on the dynamic response of the bridge. To determine its dynamic properties, a multi-setup operational modal analysis was performed on one of the bridge spans. In parallel, a structural model of the span was developed based on the available design and service life information. Both eigenfrequencies and mode shapes were used as reference parameters to calibrate the model. A sensitivity analysis was performed to identify the most influential design parameters. Subsequently, a genetic algorithm was applied for minimizing the difference between measured and simulated characteristic responses. In the proposed paper, we summarize the measurements as well as the determination of the modal response of the bridge and describe the process of calibration of the structural model using the identified dynamic response. T2 - 11th International Operational Modal Analysis Conference (IOMAC 2025) CY - Rennes, France DA - 20.05.2025 KW - Bridge structure KW - Operational modal analysis KW - Model calibration PY - 2025 SN - 978-84-09-75120-4 SP - 114 EP - 121 PB - International Group of Operational Modal Analysis CY - Gijón, Spain AN - OPUS4-64416 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir A1 - Rohrmann, Rolf ED - Döhler, Michael T1 - Modal analysis of road and rail bridges for damage detection and resonance prediction N2 - In the 1980s, the Federal Institute of Material Research and Testing started with modal analysis measurements of some bridges before and after repair. For one of the bridges, a structural health monitoring was installed 1994 which is still working up to now. It has been modified and extended several times. The monitoring was extended from the critical span to three neighbouring spans. A modal analysis of the whole bridge with seven spans have been done three times, twice together with EMPA of Switzerland. Additional calibration measurements have been done and additional evaluation procedures have been implemented for the monitoring of the steadily increasing loads from the road traffic. Additional sensors were installed such as strain gauges, crack-width, and temperature sensors. The strong influence of the temperature on the natural frequencies has been studied over the years. Later, a temperature compensation has been established and a weak aging trend has been found in the monitoring data. Now, the bridge will be demolished and replaced by a new bridge. Some results of this long-term monitoring will be shown and possible damages (changes of the pre-stress or the support structure) will be discussed. A second application of modal analysis will be demonstrated: the prediction of the resonances due to passing trains. The response of a bridge to passing trains can be calculated in frequency domain as the multiplication of three spectra, the axle sequence spectrum of the train, the transfer function of the bridge, and the modal force spectrum of a single passing load. A resonance occurs if a maximum of the train spectrum coincides with the maximum of the bridge spectrum. The amplitude at this resonance is strongly influenced by the modal force spectrum which is identical to the frequency or wavenumber spectrum of the corresponding mode shape. Therefore, modal analysis from calculation, impact measurements, wind and train measurements are necessary for the prediction of the resonance occurrence and amplification. Examples of mode shape spectra for single or multi-span bridges with simply supported or continuous spans will be shown, and some relations between mode shapes and resonance amplifications will be concluded. T2 - 11th International Operational Modal Analysis Conference (IOMAC) CY - Rennes, France DA - 20.05.2025 KW - Bridge monitoring KW - Multi-span bridges KW - Damage detection KW - Resonance PY - 2025 SP - 39 EP - 46 PB - INRIA CY - Rennes AN - OPUS4-63473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Song, Jiaojiao T1 - Analysis of intact and damaged (floating) slab tracks by finite-element boundary-element models and by measurements N2 - The damage detection and repair control have become important tasks for slab tracks. Different intact and damaged slab tracks have been investigated theoretically and experimentally for train passages and hammer impacts. The following damages have been considered: The loss of contact between the sleeper and the track slab, between the track slab and the base slab, and between the base slab and the base layer. At first, a slab track with a gap between the track slab and the base layer has been calculated by the combined finite-element boundary-element method which correctly incorporates the behaviour of the infinite soil. The basic results are the track displacements of the rail, the track slab, and the base layer along the track which are caused by a single axle load. These solutions are properly superposed for to get the complete train load. The influence of track and soil parameters and of the track damage has been analysed. For the intact track, the compliance of the soil is dominant whereas the track bending stiffness becomes more important for the damaged track. By comparing the calculated results with the measurements, the length of the gap could be quantified. A slab track with a loose sleeper (without contact to the supporting track slab) was analysed by the transfer function between the displacements and the hammer force (receptance functions) where a resonance appeared in case of the damage. Differences between the different track elements confirmed the detection of the damage. A floating slab track with a thin rubber layer has been investigated for a possible gap between the base slab and the base layer. The behaviour of the intact track has been calculated by a wavenumber-domain method, and the same behaviour has been found in the measurements at several track sections, indicating that there is no damage. Finally, a floating slab track with steel springs and viscous fluid dampers has been measured in the Tongji laboratory. The modes of the floating track slab and the transfer function with corresponding resonances have been calculated and successfully compared with results from wheelset drop tests. T2 - Third International Conference on Rail Transportation (ICRT2024) CY - Shanghai, China DA - 07.08.2024 KW - Railway track KW - Damage KW - Vibration measurement KW - Finite element method KW - Boundary element method KW - Frequency response function KW - Moving load response KW - Floating slab track PY - 2025 SN - 978-0-7844-8594-1 SP - 591 EP - 600 AN - OPUS4-61267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Thoralf A1 - Lehmann Schlag, Jens A1 - Burkert, Andreas T1 - KorroPad®-Ein Kurzzeitprüfverfahren zur Qualitätssicherung der Oberflächen- und Schweißnahtnachbearbeitung nichtrostender Stähle N2 - Die Ausbildung einer stabilen Passivschicht ist entscheidend für den Korrosionsschutz nichtrostender Stähle. KorroPad® bietet eine schnelle, zerstörungsfreie Bewertung der Passivschichtstabilität und ist seit 2025 als DIN 50024 genormt. Die Methode ermöglicht eine 15‑minütige Vor‑Ort‑Prüfung ohne Spezialwissen und schließt die Lücke zwischen teuren Laborverfahren und fehlender prozessbegleitender Qualitätssicherung. Der Beitrag beschreibt Funktionsprinzip, Anwendung sowie Beispiele aus der Oberflächen- und Schweißnahtbearbeitung. T2 - 43. Vortrags- und Diskussionstagung Werkstoffprüfung 2025 CY - Dresden, Germany DA - 26.11.2025 KW - KorroPad KW - Nichtrostender Stahl KW - Korrosion KW - Passivität PY - 2025 SN - 978-3-88355-454-9 VL - 43 SP - 1 EP - 7 PB - DGM Deutsche Gesellschaft für Materialkunde e.V. CY - Sankt Augustin AN - OPUS4-64933 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klaus, Christian A1 - Soruco Aloisio, Ricardo A1 - Koch, Claudia A1 - Prellwitz, Matthias T1 - Towards Safety and Accuracy of Hydrogen Refuelling Stations through Digital Twins N2 - This paper presents digital quality infrastructure methods for hydrogen refueling stations using the Asset Administration Shell as a standardized digital twin. Implemented at BAM’s test platform, it integrates real-time sensor data, calibration certificates, and compliance documents to support traceable, interoperable asset management. In combination with AI and semantic tools, the system will enable predictive maintenance, remote audits, and improved safety. This approach reduces downtime, enhances transparency, and offers a scalable model demonstrating the potential of digital twins in advancing metrological traceability and operational efficiency in hydrogen technologies. T2 - IMEKO TC-6 International Conference on Metrology and Digital Transformation - M4DConf 2025 CY - Benevento, Italy DA - 03.09.2025 KW - Datenintregration KW - IT KW - Verwaltungsschale KW - Infrastruktur KW - OT KW - Open Source KW - Software PY - 2025 UR - https://www.m4dconf.org/ UR - https://www.sciencedirect.com/journal/measurement-digitalization SP - 1 EP - 6 AN - OPUS4-64951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grohmann, Maria A1 - Niederleithinger, Ernst T1 - Application of Elastic Reverse Time Migration to Ultrasonic Echo Data from Concrete Structures N2 - To enhance ultrasonic imaging of concrete structures, we adapted the geophysical migration method, Reverse Time Migration (RTM), for non-destructive testing (NDT) in civil engineering. First, two 2D elastic RTM algorithms, each considering different wave types, were implemented and evaluated with synthetic ultrasonic data. The algorithm that best resolved numerical concrete structures was subsequently applied to real ultrasonic data from a concrete specimen. Compared with conventional synthetic aperture focusing technique (SAFT) imaging, elastic RTM reproduced a greater number of structural features in both the numerical model and the concrete specimen. In particular, elastic RTM reconstructed vertical interfaces as well as hidden lower edges of modeled cavities and tendon ducts. Notably, imaging the full cross-sections of tendon ducts, which enables direct diameter estimation, represents a novel achievement for ultrasonic NDT. T2 - NDT-CE 2025 - The International Symposium on Nondestructive Testing in Civil Engineering CY - Izmir, Turkey DA - 24.09.2025 KW - Concrete Structures KW - Ultrasonic Echo Technique KW - Ultrasonic Imaging KW - Elastic Reverse Time Migration KW - Synthetic Aperture Focusing Technique PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650350 DO - https://doi.org/10.58286/31680 SN - 1435-4934 SP - 1 EP - 3 PB - e-Journal of Nondestructive Testing CY - www.ndt.net AN - OPUS4-65035 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. A1 - Günzel, Stephan A1 - Bock, Robert T1 - Risk management and consequence control in hydrogen transport - volume dependent pressure limitation as a scientific approach for consequence control N2 - With technological development, the transport units for compressed gases are becoming larger and their number is increasing. Simultaneously, the filling pressure for hydrogen in transport has increased far beyond the 200 bar, which has been the common European standard for decades. In total, this increases the potential consequences of an incident, which needs to get limited for ensuring acceptance in current practice with pressure vessels from large serial production. Consequently, the measures for new developments of extremely large and highly pressurised pressure vessels should meet a risk based higher level of requirements. For this purpose, the so-called pressure-volume product was proposed as a safety related criteria to the relevant regulatory bodies in 2020. The approach was accepted, and a working group was set up at the United Nations for developing a broadly accepted limitation of today's established pressure vessels compared to future units with even more gas content. The path to the finally decided limit value of 1.5 million bar litres is presented here for hydrogen with its individual steps: ‘Boundary between major accident and disaster’, ‘The effect of pressure waves on the human body’, ‘The propagation of pressure waves’, ‘The reference value for population density’ and ‘Impact of pressure waves’. This result of the UN working group has been accepted in December 2023 and will lead to a binding limitation of the pressure volume product for the so called pressure receptacles by 2027. The work on units larger than this pV-limit is going on at ISO level. T2 - 11th International Conference on Hydrogen Safety ICHS 2025 CY - Seoul, South Korea DA - 22.09.2025 KW - Safety KW - Hydrogen transport KW - Major accident KW - Pressure wave KW - Population density KW - UN Model Regulations PY - 2025 SP - 1 EP - 14 AN - OPUS4-64199 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nattuveettil, Keerthana A1 - Liebner, Christian A1 - Tiebe, Carlo T1 - Hydrogen safety- Dealing with Closed Spaces N2 - Hydrogen is under discussion as a potentially clean energy source, but its safe usage and handling in enclosed environments remains a critical challenge due to the properties of hydrogen. This work focuses on detecting and monitoring hydrogen concentration in closed spaces to improve safety by developing a sensor network-based leak detection system to prevent of the accumulation of hazardous mixtures. Furthermore, the study details the implementation of a hydrogen sensor network within a container, analysing sensor placement, data collection, and safety improvements. The findings contribute to better risk assessment and enhanced safety protocols in hydrogen storage and usage facilities. T2 - SMSI 2025 CY - Nuremberg, Germany DA - 06.05.2025 KW - Sensor Network KW - Hydrogen safety KW - QI-Digital PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640630 SN - 978-3-910600-06-5 DO - https://doi.org/10.5162/SMSI2025/C6.2 SP - 167 EP - 168 PB - AMA Verband für Sensorik und Messtechnik e.V. CY - Berlin AN - OPUS4-64063 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klippel, Andrea A1 - Hofmann-Böllinghaus, Anja A1 - Heydick, Lukas A1 - Piechnik, Kira A1 - Wu, Hongyi A1 - Köhler, Florian T1 - Experimental Analysis of Fire Behaviour in Pine Forests and Agricultural Fields Large Scale Tests conducted within the TREEADS Project N2 - In two large-scale tests fire spread mechanisms in vegetation ground fires were studied in a pine forest and a crop field. Both fires were ignited with a drip torch using a gasoline-diesel mix. The tests were part of the European TREEADS project, specifically in the research work from the German Pilot focusing on Saxony-Anhalt and Brandenburg. These regions are known for dry, sandy soil, with pine trees covering approximately 73% of forested areas in Brandenburg and 48% in Saxony-Anhalt. The results of both experiments make a substantial contribution to optimizing extinguishing methods and strategies and enhancing a continued wildfire research in Germany. The test areas included a 16 x 22 m plot in a Saxony-Anhalt pine forest and a 20 x 100 m plot on a crop field, with fires ignited along a line using a drip torch at both locations. Fire spread was monitored with video and IR cameras mounted on a drone. In the pine forest, 96 thermocouples and gas sensors were attached to trees and a mobile FTIR spectrometer was used for real-time gas measurements. A protective strip was created around the test area using a soil tiller and fire-retardant foam to prevent uncontrolled fire spread. The experiment showed a consistent temperature rise as the fire was ignited and spread. Thermocouple data captured detailed thermal dynamics, while tree-mounted gas sensors recorded significant fluctuations in combustible gases. Real-time gas spectra from the FTIR spectrometer enabled precise smoke analysis. Conducted in stable weather - 23°C, light wind, low soil moisture—this setup improved reproducibility, with a weather station monitoring temperature, humidity and wind conditions to assess fire-environment interactions. After ignition process the fire showed a slow spread and distinct combustion phases. Smouldering was more pronounced in areas with grasses and deadwood, highlighting vegetation-specific burn patterns critical to wildfire research. The experiment showed numerous smouldering and burning spots, with flames igniting and extinguishing repeatedly. However, flame height did not exceed half a meter. Due to substantial smoke production, visibility in the test field was limited and team members wore respirators to collect specific smoke gases such as benzene and formaldehyde for analysis. Field measurements showed flame temperatures exceeding 500°C. Toxic smoke gas concentrations of up to 238 ppm CO were measured, although precise gas capture appeared challenging due to wind turbulence. The second large-scale area in Nauen, a cut wheat field (stubble height approx. 30 cm) was burned, with fire spreading across approximately 700 m². A 20 m ignition line directed flames with the wind. Fire spread was observed using drones equipped with IR cameras. Experiments demonstrated how unpredictable and challenging it is to measure large outdoor fires. To enable a comprehensive theoretical and numerical description of fire dynamics in wildfires, it is essential to conduct further large-scale experiments. T2 - Interflam 2025, 16th International Fire Science and Engineering Conference CY - London, United Kingdom DA - 30.06.2025 KW - Wildfire PY - 2025 SP - 1435 EP - 1444 PB - Interscience CY - London AN - OPUS4-63926 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hofmann-Böllinghaus, Anja A1 - Klippel, Andrea A1 - Piechnik, Kira T1 - Vehicle fires: significant fire hazard in transportation infrastructure 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. T2 - Interflam 2025, 16th International Fire Science and Engineering Conference CY - London, United Kingdom DA - 30.06.2025 KW - Vehicle fires PY - 2025 SP - 1291 EP - 1298 PB - Interscience CY - London AN - OPUS4-63924 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Piechnik, Kira A1 - Hofmann-Böllinghaus, Anja A1 - Klippel, Andrea T1 - Characterization and assessment of smoke emissions from smouldering forest fires: a combined experimental and numerical approach N2 - This article builds upon the publication "Comprehensive Laboratory Study on Smoke Gases During the Thermal Oxidative Decomposition of Forest and Vegetation Fuels"1 in Fire and Materials, 2024, summarizing the experimental methodology and highlighting key findings. The study investigates the gas-phase composition of smoke emissions from forest and vegetation fuels. The study focuses on pine-dominated ecosystems in Eastern Germany, with the objective of improving the understanding of wildfire-related gaseous emissions, as a contribution to the German pilot activities within the EU Project TREEADS. Using a modified DIN tube furnace in a bench-scale setup, the investigation centers on gaseous emissions from five trees and two ground cover species, explicitly excluding particulate matter. T2 - Interflam 2025, 16th International Fire Science and Engineering Conference CY - London, UK DA - 30.06.2025 KW - Wildfire PY - 2025 SP - 288 EP - 294 PB - Interscience CY - London AN - OPUS4-63999 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mente, Tobias A1 - Grimault de Freitas, Tomás A1 - Nietzke, Jonathan A1 - Konert, Florian A1 - Sobol, Oded A1 - Wackermann, Ken A1 - Ruchti, Peter A1 - Elsen-Humberg, Stefan A1 - Systermans, Thomas ED - Zimmermann, Martina T1 - Hohlzugprüfung als kostengünstige Methode zur Werkstoffcharakterisierung für die Wasserstoffwirtschaft N2 - Wasserstoff ist ein notwendiger Baustein zur Erreichung zukünftiger Klimaziele. Für eine schnell hochlaufende Wasserstoffwirtschaft ist es daher notwendig sowohl bestehende Infrastruktur als auch neue Werkstoffe für den sicheren und nachhaltigen Einsatz in Wasserstofftechnologien zu qualifizieren. Die akzeptierten und standardisierten Prüfverfahren zur Ermittlung des Einflusses gasförmigen Wasserstoffs auf die mechanischen Eigenschaften metallischer Werkstoffe sind meist sehr komplex, mit hohem technologischem und finanziellem Aufwand verbunden und stehen nur Wenigen Instituten weltweit zur Verfügung. Die Hohlzugprüftechnik bietet hier eine kostengünstige und einfach zu realisierende Alternative. Mit der im Jahr 2024 erstmals veröffentlichten ISO 7039 wurde diese Prüftechnik auch für die Wirtschaft anwendbar gemacht. Der Standard gilt allgemein für die Prüfung mit gasförmigen Medien, weist jedoch in Bezug auf die Prüfung mit gasförmigem Wasserstoff noch einige Wissenslücken auf. Im Teilvorhaben H2HohlZug des Leitprojekt TransHyDE werden die Lücken zum Einfluss der Geometrie, Oberflächenqualität sowie Gasreinheit in einzelnen Arbeitspaketen geschlossen und die Erkenntnisse in einen Standard überführt. T2 - 43. Vortrags- und Diskussionstagung Werkstoffprüfung 2025 - Werkstoffe und Bauteile auf dem Prüfstand CY - Dresden, Germany DA - 27.11.2025 KW - Hohlzugprüfung KW - Druckwasserstoff KW - ISO 7039 KW - H2HohlZug - TransHyDE PY - 2025 SN - 978-3-88355-454-9 SP - 11 EP - 17 PB - Deutsche Gesellschaft für Materialkunde e.V. (DGM) CY - Dresden AN - OPUS4-64937 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Leo, Reinhold A1 - Sobol, Oded A1 - Hango, Silas Ithete A1 - Saliwan Neumann, Romeo A1 - Askar, Enis A1 - Boellinghaus, Thomas T1 - Ex-situ investigation of the compatibility of Duplex Stainless Steel for high-pressure hydrogen applications N2 - The key to a successful transition into clean energy carriers such as hydrogen requires the construction of safe transportation pipelines made of alloys which are not susceptible to hydrogen assisted cracking. Duplex Stainless Steels (DSS) are considered as a proper class for components because of their many distinctive qualities. As this consideration depends strongly on the susceptibility level to Hydrogen Assisted Cracking (HAC), the DSS class has been broadly investigated under electrochemical charging conditions. In this work, the interplay between several factors controlling the level of HAC, was examined using light microscopy, high-pressure gaseous hydrogen pre-charging, Electron Backscatter Diffraction (EBSD), tensile testing, fractography and hydrogen concentration measurements using Carrier Gas Hot Extraction (CGHE). The effect of gaseous hydrogen on the mechanical properties with the role of hydrogen induced phase transformation have been investigated both in unused material and in high pressure pipeline section. In contrary to the common electrochemical charging described broadly in the literature, no significant martensitic phase transformation of the austenitic phase was observed. On the other hand, the influence of hydrogen on parameters such as elongation at fracture and reduction of area was noticeable. It is concluded based on the performance of DSS in gaseous hydrogen, that this material has a better potential for utilization in hydrogen applications. As for future experiments, the intention is to analyse the impact of high-pressure gaseous hydrogen on the welded components of this grade, and under mechanical load using the hollow specimen technique. T2 - 5th International Conference on Metals and Hydrogen CY - Ghent, Belgium DA - 14.10.2025 KW - High-Pressure Hydrogen KW - Pipelines KW - Duplex Stainless Steels KW - Hydrogen Assisted Cracking KW - Hollow Specimen Technique PY - 2025 SN - 978-9-08179-424-4 SP - 1 EP - 19 AN - OPUS4-64426 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Askar, Enis A1 - Schmidt, Martin A1 - El Harrab, Hayat A1 - Pekalski, Andrzej T1 - Ignition Indices of Hydrogen Mixtures under Electrolysis Process Conditions N2 - The formation of hydrogen-oxygen mixtures for example due to cross-over, malfunction or start-up and shut-down processes is a hazard very specific to given electrolysis processes that must be properly addressed. In this work the explosion limits of hydrogen-oxygen-mixtures at conditions up to 30 bar and 300 °C were determined experimentally. It was found that the existing experimental data can be interpolated with good accuracy using empirical approaches. Moreover, explosion limits at atmospheric conditions were also determined with reduced ignition energy, down to 1 mJ. Although in the literature it can be found that the ignition energy of flammable gases increases strongly when the concentration changes from stoichiometric to near the explosion limits, no significant influence on the mixture concentration was found within tested ignition energy range for H2/O2 mixtures. Finally, hot surface ignition for mixtures with 6 mol% hydrogen in oxygen, thus slightly above the explosion limit, were experimentally studied at different pressures up to 30 bara. Similarly, only slight difference from the ignition temperatures determined for stoichiometric mixtures were found. A 0D adiabatic, constant-volume reactor model was used to calculate the ignition temperatures. The model was tested for its prediction of ignition temperatures of hydrogen mixtures at different pressures. T2 - 11th International Conference on Hydrogen Safety (ICHS) 2025 CY - Seoul, South Korea DA - 22.09.2025 KW - Explosion limits KW - Ignition temperature KW - Ignition energy KW - Electrolyzer PY - 2025 SN - 979-12-243-0274-2 VL - 11 SP - 1259 EP - 1271 AN - OPUS4-64525 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gluth, Gregor ED - Wittke, W. T1 - Alkalisch aktivierter Beton (Geopolymer-Beton) N2 - Alkalisch aktivierte Bindemittel (AAB) sind Zemente, deren Erhärtung auf der alkalischen Anregung von reaktiven Aluminiumsilicaten beruht. AAB sind nach gegenwärtigem Stand die vielversprechendste Option, die mit der Herstellung und dem Einsatz von Zementen verbundenen CO2-Emissionen mittel- bis langfristig signifikant zu senken. Die Erhärtungsreaktionen und die Einflüsse auf die Mikrostruktur von AAB sind durch jahrzehntelange Forschung gut verstanden, und zahlreiche Beispiele belegen, dass AAB grundsätzlich als Betonbindemittel geeignet sind. Offene Fragen bestehen aber immer noch hinsichtlich der Dauerhaftigkeit von mit AAB hergestellten Betonen. Der vorliegende Beitrag gibt eine kurze Einführung in die Nomenklatur und die Geschichte von AAB. Die wichtigsten Reaktionen und Reaktionsprodukte, die zur Bildung der Mikrostruktur von AAB führen, werden beschrieben. Der Hauptteil des Beitrags diskutiert aktuelle Forschungsergebnisse und offene Fragen zur Dauerhaftigkeit von Betonen auf Basis von AAB. Wichtige Fortschritte auf diesem Gebiet konnten in den letzten Jahren insbesondere zum Einfluss von Sulfiden auf die Bewehrungskorrosion, zum Carbonatisierungswiderstand und zum Säurewiderstand erzielt werden. T2 - 10. Felsmechanik- und Tunnelbautag CY - Weinheim, Germany DA - 22.05.2025 KW - Alkali-activated materials KW - Carbonation KW - Reinforcement corrosion KW - MIC KW - Microbially induced corrosion PY - 2025 SN - 978-3-00-083562-9 SP - 73 EP - 84 PB - WBI GmbH CY - Weinheim AN - OPUS4-64266 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nicolicea, Alberto A1 - Pelkner, Matthias A1 - Melzer, Michael A1 - Oliveros-Mata, E. S. A1 - Zabila, Y. A1 - Makarov, D. T1 - Flexible AMR sensors for novel non-destructive testing capabilities N2 - Reshapeable magnetic field sensors fabricated on flexible substrates by thin-film deposi-tion or printing have recently emerged with promising applications in different field. In this study, flexible anisotropic magneto-resistive (AMR) sensors were used for the scanning of a curved and flat sample with reference defects, to prove the capability of this method for curved surface scanning, and to benchmark the performance when compared to a more standard method using rigid giant magneto-resistive (GMR) sensors. Defects with depths ranging from 110 μm up to 2240 μm were detected with a signal-to-noise ratio (SNR) of 2.7 up to 27.9 employing flexible AMR sensors. T2 - XMR-Symposium CY - Wetzlar, Germany DA - 12.03.2025 KW - non-destructive testing KW - Flexible sensor KW - Magnetoresistance PY - 2025 SP - 1 EP - 6 AN - OPUS4-65045 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Xiangmeng A1 - Bachmann, Marcel A1 - Kising, Pascal A1 - Yang, Fan A1 - Rethmeier, Michael T1 - Prediction of weld pool and keyhole geometries in high-power laser beam welding through a physics-informed generative artificial intelligence approach N2 - The weld pool and keyhole geometries are critical characteristics in evaluating the stability of the high-power laser beam welding (LBW) process and determining the resultant weld quality. However, obtaining these data through experimental or numerical methods remains challenging due to the difficulties in experimental measurements and the high computational demands of numerical modelling. This paper presents a physics-informed generative approach for predicting weld pool and keyhole geometries in the LBW process. With the help of a well experimentally validated numerical model considering the underlying physics in the LBW, the geometries of the weld pool and keyhole under various welding conditions are calculated, serving as the dataset of the generative model. A Conditional Variational Autoencoder (CVAE) model is employed to generate realistic 2D weld pool and keyhole geometries from the welding parameters. We utilize a β-VAE model with the Evidence Lower Bound (ELBO) loss function and include Kullback-Leibler divergence annealing to better optimize model performance and stability during training. The generated results show a good agreement with the ground truth from the numerical simulation. The proposed approach exhibits the potential of physics-informed generative models for a rapid and accurate prediction of the weld pool geometries across a diverse range of process parameters, offering a computationally efficient alternative to full numerical simulations for process optimization and control in laser beam welding processes. T2 - International Congress of Applications of Lasers & Electro-Optics 2025 CY - Orlando, USA DA - 12.10.2025 KW - Laser beam welding KW - Generative artificial intelligence KW - Machine learning KW - numerical simulation PY - 2025 SP - 1 EP - 10 AN - OPUS4-65075 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 - Channammagari, Harichandana A1 - Sahr, Rabea A1 - Trappe, Volker T1 - Experimentelle, Analytisch-Numerische Untersuchung des thermischen Ausdehnungsverhaltens von Faser-Kunststoff-Verbunden N2 - Im Rahmen des Forschungsvorhabens PROVING wurde eine Methode zur rechnerischen Bestimmung thermomechanischer Eigenspannungen in CFK entwickelt. Ziel ist die Berücksichtigung des thermischen Ausdehnungsverhaltens bei der Bestimmung des dreidimensionalen in-situ-Spannungszustands der Matrix für den strukturellen Nachweis. Die Eigenspannungen werden über mikromechanische Modellierung und FEM berechnet; die zugrunde liegenden Ausdehnungsfunktionen wurden experimentell validiert. N2 - As part of the PROVING research project, a method for calculating thermomechanical residual stresses in CFRP was developed. The aim is to take thermal expansion behavior into account when determining the three-dimensional in-situ stress state of the matrix for structural verification. The residual stresses are calculated using micromechanical modeling and FEM; the underlying expansion functions have been experimentally validated. T2 - 43. Vortrags- und Diskussionstagung Werkstoffprüfung 2025 CY - Dresden, Germany DA - 27.11.2025 KW - Thermische Eigenspannungen KW - Mikromechanik KW - Faser-Kunststoff-Verbunde KW - FEM PY - 2025 SN - 978-3-88355-454-9 VL - 2025 SP - 154 EP - 159 PB - DGM CY - Sankt Augustin AN - OPUS4-65112 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Huo, Wenjie A1 - Schmies, Lennart A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael A1 - Wolter, Katinka T1 - An illumination based backdoor attack against crack detection systems in laser beam welding N2 - Deep neural networks (DNNs) have been wildly used in engineering and have achieved state-of-the-art performance in prediction and measurement tasks. A solidification crack is a serious fault during laser beam welding and it has been proven to be successfully detected using DNNs. Recently, research on the security of DNNs is receiving increasing attention because it is necessary to explore the reliability of DNNs to avoid potential security risks. The backdoor attack is a serious threat, where attackers aim to inject an inconspicuous pattern referred to as trigger into a small portion of training data, resulting in incorrect predictions in the reference phase whenever the input contains the trigger. In this work, we first generate experimental data containing actual cracks in the welding laboratory for training a crack detection model. Then, targeting this scenario, we design a new type of backdoor attack to induce the model to predict the crack as a normal state. Considering the stealthiness of the attack, a common phenomenon during the welding process, illumination, is used as the backdoor trigger. Experimental results demonstrate that the proposed method can successfully attack the crack detection system and achieve over 90% attack success rate on the test set. T2 - 8th ML4CPS 2025 – Machine Learning for Cyber-Physical Systems CY - Berlin, Germany DA - 06.03,2025 KW - System security KW - Welding crack detection KW - Backdoor attack KW - Deep neural networks PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651357 DO - https://doi.org/10.24405/20021 VL - 2025 SP - 12 EP - 21 PB - Universitätsbibliothek der HSU/UniBw H CY - Hamburg AN - OPUS4-65135 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wu, Hongyi A1 - Buhk, Frederik A1 - Christiani, Ricardo A1 - Hofmann-Böllinghaus, Anja T1 - Influence of local vegetation on ignition and fire spread of vegetation fires-Experimental and numerical approach N2 - Within the framework of the European TREEADS project, Brandenburg and Saxony-Anhalt were designated as model regions. This designation facilitated the investigation of vegetation types, soil structure, and soil dryness. Brandenburg and Saxony-Anhalt are identified as the driest regions in Germany according to the annual mean soil moisture data. In these regions, 48% to 73% of the forests are composed of pine species. The soil profile is characterized by a relatively thin organic layer, measuring between 0.2 and 0.3 meters, underlain by sandy substrates. Consequently, surface and ground fires are more prevalent in these areas compared to other types of fires, such as crown fires. To investigate the influence of local vegetation, it goes through two aspects. One is laboratory study, the local vegetation samples were collected and tested for the thermal properties, such as activation energy, heat content and reaction kinetic of pyrolysis and dehydration. At the same time, small and medium scale combustion experiments were conducted to investigate the burning behavior. The other aspect is using the thermal properties as the input parameters for the development of numerical simulation in the computational fluid dynamics (CFD) tool. These models were then be validated with the combustion experiments, as a baseline for the further scaling up of the models, in order to investigate how the parameters influencing the fire spread in a large-scale case numerically. T2 - Interflam 2025, 16th International Fire Science and Engineering Conference CY - London, United Kingdom DA - 30.06.2025 KW - Wildfire PY - 2025 SP - 2221 EP - 2225 PB - Interscience CY - London AN - OPUS4-63932 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 - Baeßler, Matthias A1 - Simon, Patrick ED - Cunha, Álvaro ED - Caetano, Elsa T1 - Review of Ballasted Track Destabilization on Shake Table Tests N2 - Shake table tests have been used for a long time to understand the densification and fluidization of granular materials. While purely vertical shaking is quite unlikely to be found in vibration analysis when it comes to granular materials as soils, it has been found that the vertical vibration of railway bridge support structures can affect the fabric of the ballasted track on top. Starting from the experience at French railway lines with destabilizing track conditions on short bridges in high speed lines in the 1990s, various shake table test configurations have been used to investigate the destabiliza-tion of ballast at high acceleration levels. This article describes the effects of the variously investigated dynamic excitations of railway bridges on the bal-lasted track itself. T2 - 11th International Conference on Experimental Vibration Analysis for Civil Engineering Structures (EVACES 2025) CY - Porto, Portugal DA - 02.07.2025 KW - Infrastructure KW - Ballasted track KW - Ballast KW - Railway bridge dynamics PY - 2025 SN - 978-3-031-96105-2 DO - https://doi.org/10.1007/978-3-031-96106-9_62 SP - 595 EP - 604 PB - Springer CY - Cham AN - OPUS4-64265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - Characteristic Frequencies of Train-Induced Bridge, Track, Ground and Building Vibrations – Excitation and Mitigation N2 - The characteristic frequencies of train-induced vibrations are discussed in theory and experiment following the propagation of vibrations from the source to the receiver: 1. Out-of-roundness frequencies of the wheels, 2. sleeper-passage frequency, 3. the vehicle-track eigenfrequency, 4. band frequency of the impulses of the passing static axle loads, 5. car-length frequency and multiples, 6. axle-distance frequencies with two characteristic zeros, 7. bridge eigenfrequencies, 8. the cut-on frequency due to the layering, and 9. the cut-off frequency due to the material damping of the soil, 10. the building-soil eigenfrequency, 11. as a rigid building or flexible wall/column mode, 12. floor eigenfrequencies, 13. acoustic room resonances, 14. the „resonance“ frequency or cut-off frequency of a base isolation. Coincidences of some of these characteristic frequencies or frequency ranges can be typically problematic and mitigation measures at the track or at the building can be necessary. The bridge response to the passing static loads is deter¬mined by the axle-sequence spectrum, the eigenfrequency (transfer function) of the bridge, and the modal force or mode shape spectrum. The ground vibration has typically high frequencies for a stiff soil and low frequencies for a soft soil. The high amplitudes between the zeros of the axle-sequence spectrum are often measured in the ground vibrations, and they can be mitigated by soft support elements or a higher bending stiffness of the track. T2 - EVACES 2025 CY - Porto, Portugal DA - 02.07.2025 KW - Train-induced vibration KW - Vehicle excitation KW - Track response KW - Bridge resonance KW - Ground vibration KW - Soil-building transfer KW - Floor resonance KW - Axle-sequence spectrum KW - Vehicle-track eigenfrequency KW - Axle impulses PY - 2025 SN - 978-3-031-96113-7 DO - https://doi.org/10.1007/978-3-031-96106-9_77 VL - 2025 SP - 1 EP - 8 PB - Springer CY - Cham, Schweiz AN - OPUS4-63655 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 - Simon, Patrick A1 - Baeßler, Matthias ED - Cunha, Álvaro ED - Caetano, Elsa T1 - On the reassessment of bridge superstructure vibrations for high-speed traffic N2 - The acceleration thresholds of bridge superstructures remain critical for designing and reassessing railway bridges on high-speed lines, with ballasted track systems historically limited to 3.5 m/s2 vertical accelerations due to destabilization risks. As part of the European InBridge4EU project, this study addresses methodological uncertainties in linking vertical bridge vibrations to lateral track creep—a key focus area for modernizing assessment protocols. A comparative analysis of two acceleration postprocessing methods (peak identification vs. fatigue-derived rainflow counting) as part of a recently proposed framework was conducted using an example bridge and train combination. Results demonstrate that rainflow counting yields more conservative creep estimates with the bulk of cumulative vibration-induced creep attributable to accelerations exceeding 3 m/s2. However, discretizing acceleration ranges into 1 m/s2 bins introduced significant errors compared to continuous cycle data, highlighting sensitivity to analysis parameters. These findings underscore the complexity of reconciling laboratory-derived harmonic vibration models with real-world bridge dynamics, where non-uniform acceleration patterns dominate. The research directly informs ongoing efforts to refine standardized criteria for ballasted track stability, particularly through the InBridge4EU project’s systematic re-evaluation of vibration limits and their engineering implications. By quantifying discrepancies between computational approaches, this work advances the development of robust protocols for predicting track degradation under high-speed operational loads. T2 - 11th International Conference on Experimental Vibration Analysis for Civil Enginering Structures (EVACES 2025) CY - Porto, Portugal DA - 02.07.2025 KW - Infrastructure KW - Railway bridges KW - Ballast destabilization KW - Acceleration limit KW - Ballasted track KW - Rainflow counting PY - 2025 SN - 978-3-031-96105-2 DO - https://doi.org/10.1007/978-3-031-96106-9_53 VL - 675 SP - 506 EP - 515 PB - Springer CY - Cham AN - OPUS4-64267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liao, Chun-Man A1 - Bernauer, F. A1 - Niederleithinger, Ernst A1 - Igel, H. A1 - Hadziioannou, C. T1 - Assessment of prestress loss in a large-scale concrete bridge model under outdoor condition N2 - Environmental conditions affect the accuracy of field measurements used to monitor civil structures. Previous studies have shown that measured dynamic responses often lack the sensitivity needed for effective localized damage detection. To address this issue, our study focuses on distinguishing environmental effects from damage related effects in measured data to enhance vibration-based damage identification methods. Experimentally, the problem of prestress loss in a prestressed concrete bridge model was examined. By adjusting the pre-stressing force in a large-scale concrete bridge model, cracking phenomena were observed. To demonstrate field monitoring of a large-scale prestressed structure, noise recording was performed and the measurement data was analyzed with operational modal analysis. Additionally, ultrasonic testing, known for its high sensitivity in damage localization, was used to cross-check the structural damage. Seismic and coda wave interferometry were also employed to estimate wave velocities, providing insights into the level of prestress loss and temperature sensitivity. Ultimately, these measurable wave properties help to overcome the uncertainties associated with traditional vibration-based damage detection methods. T2 - EVACES 2025 CY - Porto, Portugal DA - 02.07.2025 KW - Prestress Loss KW - NDT KW - Ambient Vibration KW - Ultrasonic Testing KW - Coda Wave Interferometry KW - Seismic Interferometry PY - 2025 SN - 978-3-031-96105-2 DO - https://doi.org/10.1007/978-3-031-96106-9_20 VL - 675 SP - 181 EP - 189 PB - Springer Nature CY - Cham AN - OPUS4-64212 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Anderson, Johan A1 - Chiva, Roman A1 - Dumont, Fabien A1 - Lalu, Octavian A1 - Hofmann-Böllinghaus, Anja T1 - Assessment of fire performance of facades in a round robin using the European approach N2 - In recent years, an experimental round robin of full-scale façade tests was conducted using the proposed new European approach for assessing the fire performance of façades. The initial results were used to develop a calibration scheme and to propose assessment criteria aligned with appropriate safety levels. During the project, a need emerged to evaluate the stability of the fire source and the Consistency of heat exposure. This paper addresses these concerns by comparing the mass loss rates across a series of tests and analysing averaged temperature readings at various locations on the façade. The findings indicate that the method demonstrates high stability in terms of mass loss rates and provides consistent and appropriate heat exposure. T2 - Interflam 2025, 16th International Fire Science and Engineering Conference CY - London, UK DA - 30.06.2025 KW - Facade systems KW - Testing PY - 2025 VL - 2025 SP - 562 EP - 572 PB - Interscience CY - London AN - OPUS4-63998 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, 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 - CONF A1 - Unger, Jörg F. T1 - Methodological Prerequisites for Reliable Simulation Results in the Virtual Lab and Digital Twins N2 - Simulationen übernehmen zunehmend eine zentrale Rolle in sicherheitskritischen Entscheidungsprozessen, etwa im Bauwesen, bei digitalen Zwillingen oder in der prädiktiven Instandhaltung. Damit diese Entscheidungen auf zuverlässigen numerischen Modellen basieren können, müssen die zugrunde liegenden Teilmodelle eindeutig beschrieben, reproduzierbar und in der Community validiert sein. Dieses Manuskript skizziert die notwendigen Voraussetzungen für vertrauenswürdige, FAIR-konforme und entscheidungsfähige Simulationsprozesse. Zunächst wird die Notwendigkeit einer formalen, softwareunabhängigen Beschreibung mathematischer Modelle und numerischer Implementierungen diskutiert. Standards wie VMAP, Ontologien wie MathModDB sowie BIM- und STEP-Formate bieten erste Ansätze zur semantischen Modellbeschreibung und zur automatisierten Generierung simulationsfähiger Eingabedaten. Im zweiten Teil wird die Rolle experimenteller Daten für die Validierung von Modellen beleuchtet. Es wird gezeigt, dass hochwertige, strukturierte und maschinenlesbare Validierungsdatensätze essenziell sind, insbesondere für die Bewertung konstitutiver Modelle. Ein weiteres Kapitel widmet sich der Unsicherheitsquantifizierung. Neben klassischen Fehlermaßen werden aleatorische und epistemische Unsicherheiten sowie deren Einfluss auf die Modellbewertung behandelt. Besondere Aufmerksamkeit gilt der Bayes’schen Kalibrierung, der Trennung von Trainings und Testdaten und der Notwendigkeit, auch Begleitversuche aus Materialtests zu dokumentieren. Abschließend wird die Idee einer Benchmarking-Plattform vorgestellt, die auf reproduzierbaren Workflows, automatisierter Provenienzverfolgung und der Nutzung von Research Object (RO) Crates basiert. Diese Plattform erlaubt die dezentrale Veröffentlichung und zentrale Abfrage von Benchmark-Ergebnissen und fördert eine gemeinschaftliche Verifikation und Validierung. Ziel ist es, die Vergleichbarkeit von (Open-Source-)Simulationstools zu verbessern um dadurch komplexe experimentelle Setups zunehmend durch zuverlässige Simulationen ersetzen zu können. T2 - NAFEMS - Symbiose von Simulation und Test CY - Wiesbaden, Germany DA - 12.11.2025 KW - Verification and Validation, KW - Digital twins KW - Virtual lab KW - Uncertainty quantification PY - 2025 SN - 978-1-83979-242-7 SP - 23 EP - 28 PB - NAFEMS CY - Wiesbaden, Germany AN - OPUS4-65271 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 - Kocherla, Amarteja A1 - Strangfeld, Christoph A1 - Hüsken, Götz T1 - Embedded Sensors for Quality Control and Structural Integrity Monitoring of Large-scale 3DCP Structures N2 - In extrusion-based 3D concrete printing (3DCP), addressing challenges related to safety, reliability, and quality control is crucial for widespread adoption. Yet current limitations in monitoring material properties during and after printing hinder the development of effective 3DCP guidelines. Therefore, the development of an inline sensing system capable of real-time monitoring and adjustment of process parameters is necessary to overcome these challenges. Building upon an existing inline sensing system developed by BAM, which currently monitors material properties during printing and the geometry of the print post-extrusion, this study extends its capabilities to post-extrusion monitoring using embedded piezoelectric (PZT) sensors. These PZT sensors provide localized measurements of material changes through electrical impedance (EI) measurements without disrupting the printing process. By embedding these sensors in 3D printed structures, continuous monitoring is achieved from layer deposition through 1-day of hydration. To achieve this, initially, PZT sensors were developed with multiple layers of protective coatings. Two different 3D printed mixtures, each with different hydration behaviors, were utilized, and PZT sensors were strategically placed between printed layers to maintain their integrity. EI measurements were collected continuously from printing through 1 day of hydration. Analysis of amplitude and frequency changes in the EI response spectrum provided insights into material behavior post-printing. The study highlights how continuous monitoring of frequency and conductance can track structural builtup and property development of the material. Rapid changes in conductance measurements, immediately post-printing indicate swift structural built-up, while key hydration phases are reflected in frequency measurements. T2 - 34th Annual Conference and Exhibition on Non Destructive Evaluation & Enabling Technologies CY - Chennai, India DA - 12.12.2024 KW - Embedded Sensors KW - 3D Concrete Printing KW - Quality Control KW - Inline Sensing KW - Structural Integrity PY - 2025 SP - 1 EP - 8 PB - Springer Nature CY - Heidelberg AN - OPUS4-65305 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sauer, Hannah A1 - Okpeke, Bright Ebikemefa A1 - Dzielendziak, Agnieszka Sylwia A1 - Batcke, Lars A1 - Eberwein, Robert A1 - Ehlers, Sören T1 - Comparative life cycle assessment of different vacuum insulation panel core materials for cryogenic storage tanks – with a focus on glass bubbles as a novel core material N2 - Developing a sustainable hydrogen supply chain is important in facilitating the energy transition towards climate neutrality. Hydrogen in its free form can be stored and transported either as a gas or a liquid. Due to gaseous hydrogen's comparatively low energy density, liquefied hydrogen (LH 2) is often preferred, especially with regard to long-distance transportation and storage in bulk. A notable challenge associated with LH2 is the inherent requirement to preserve it at a low temperature of -253°C. Consequently, the utilisation of thermally insulated tanks is necessary to minimise LH 2 evaporation. There is a lack of literature on the environmental impacts of insulation materials and concepts for cryogenic storage tank applications in the hydrogen supply chain. Hence, this study investigates a novel concept, namely vacuum insulation panels (VIPs), focusing on their core materials, with a view to assessing their environmental sustainability and circularity. A cradle-to-grave life cycle assessment (LCA) model is employed to investigate six distinct VIP core materials, namely, silica aerogel, rigid polyurethane foam, expanded perlite, glass fibre, fumed silica, and glass bubbles (hollow glass microspheres), with a special focus on the latter. The LCA results show that polyurethane foam and silica aerogel rank low in environmental performance, making them less suitable as primary choice. Expanded perlite is the most environmentally friendly material option, followed by glass fibre, glass bubbles, and fumed silica. Improvements to the environmental impact of glass bubbles can be achieved via the implementation of closed-loop recycling in their life cycle. T2 - The World Hydrogen Technologies Convention 2025 CY - Dublin, Ireland DA - 21.10.2025 KW - LH2 KW - Insulation KW - Life cycle assessment PY - 2025 UR - https://www.whtc2025.com/conference-proceedings SP - 65 EP - 67 AN - OPUS4-64668 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bernardy, Christopher A1 - Habib, Abdel Karim A1 - Kluge, Martin A1 - Schalau, Bernd A1 - Schulze, Marcel A1 - Kant, Hanjo A1 - Orchini, Alessandro ED - Ruggiero, Eric J. T1 - Experimental investigation of large-scale hydrogen diffusion jet flames N2 - Hydrogen is a promising alternative to natural gas in industrial energy applications which would serve the goal of limiting global warming. However, wide application of hydrogen requires specific safety considerations taking into account that hydrogen is stored and transported under much higher pressure than natural gas. Thus, one scenario to be considered for hazard assessment is a sudden release of hydrogen from a leakage or safety valve and its subsequent ignition. For hydrocarbon flames, various jet flame models are available. However, hydrogen flames significantly differ from hydrocarbon flames in their combustion behavior, so that the applicability of these models to hydrogen has to be investigated. For that purpose, reals scale tests were carried out at the BAM Test Site Technical Safety. In addition, hydrocarbon jet flames (methane) were investigated. In these tests, the flame geometry and the thermal heat radiation were investigated for a release angle of 90°, for different release pressures (up to 220 bar) and mass flows (up to 0.175 kg/s). While existing heat radiation data from the literature are mostly based on unsteady outflow conditions and/or releases in still air, the experiments presented here are focused on ensuring a constant mass flow over the release duration under realistic free field conditions (with wind influence). This allows a better comparability with the stationary jet flame models and assessment of wind influence on model predictions. A number of parameters such as the surface emissive power of the jet flame and the radiant heat fraction were determined. A detailed comparison of the obtained experimental results with literature radiation models was performed. Good agreement between experimental and literature data was found for hydrogen whereas significant differences were identified for methane. Based on the investigations, empirical equations for modelling jet flames could be derived. T2 - American Society of Mechanical Engineers - Turbomachinery Technical Conference & Exposition GT2025 CY - Memphis, TN, USA DA - 16.06.2025 KW - Hydrogen release KW - Jet flame KW - Radiant heat fraction KW - Thermal radiation PY - 2025 SN - 978-0-7918-8877-3 DO - https://doi.org/10.1115/GT2025-FM2 SP - 1 EP - 11 PB - The American Society of Mechanical Engineers CY - Livingston AN - OPUS4-64098 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sarif, Raduan A1 - Tiebe, Carlo A1 - Herglotz, Christian T1 - Early Response Prediction for H2 Sensors N2 - Green hydrogen (H2) is essential for the global transition to clean energy; it will significantly reduce emissions from heavy industry and the long-distance transport system. H2 can be used as fuel in fuel cells, storing surplus renewable energy, and as a feedstock in industrial processes. However, H2 faces significant safety challenges during storage and transportation. Accidents due to H2 leakage and explosions raise serious concerns due to its high flammability, rapid diffusion in air, and extremely low ignition energy. To mitigate risks associated with H2 leakages, reliable and automated H2 safety systems are essential for emergency repairs or shutdown. An early response from H2 sensors is crucial for early warning in accidents. The earlier response time of H2 sensors is often constrained by their sensor principle, which is heavily influenced by the sensor material’s properties. This study explores methods for earlier sensor response through predictive algorithms. Specifically, we investigate transient response predictions using a First-Order (FO) model and propose improvements through the First-Order with early response and the First-Order with adapted early response model. Both models can predict the stable value of the H2 sensor response from a small time window, which is 70.89% and 83.72% earlier, respectively, than the time required for the sensor hardware to reach it physically. The model’s performance is evaluated by calculating the fitting error with a 2 % threshold. Our current research lays the groundwork for future advancements in real-time sensor response predictions for hydrogen leakage. T2 - IARIA Congress 2025 : The 2025 IARIA Annual Congress on Frontiers in Science, Technology, Services, and Applications CY - Venice, Italy DA - 06.07.2025 KW - H2 Safety KW - H2 leakage detection KW - First-Order (FO) model KW - H2 Sensor data analysis KW - H2 sensor response predictions PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640676 UR - https://www.thinkmind.org/articles/iaria_congress_2025_1_250_50159.pdf SN - 978-1-68558-284-5 SP - 1 EP - 8 PB - IARIA Press CY - Wilmington AN - OPUS4-64067 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sarif, Raduan A1 - Tiebe, Carlo A1 - Herglotz, Christian T1 - Analysis of Methods for Predicting H2 Sensor Responses N2 - Hydrogen (H2) is crucial for replacing fossil fuels and achieving net-zero emissions, but its flammability and explosiveness pose safety challenges. Rapid H2 leak detection is essential for triggering emergency accidents. However, H2 sensor response is constrained by material properties and gas flow dynamics, causing response and detection delays. Our current study explores various available algorithms for H2 sensor response prediction from early responses with a small time window, accelerating leakage detection. Our findings identify the most efficient algorithms for real-time implementation, enhancing H2 safety systems. T2 - SMSI 2025 2025-05-06 - 2025-05-08 Nürnberg CY - Nuremberg, Germany DA - 06.05.2025 KW - H2 safety KW - Early H2 leakage detection KW - Prediction algorithms KW - Stable H2 value prediction PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640617 SN - 978-3-910600-06-5 DO - https://doi.org/10.5162/SMSI2025/C6.3 SP - 169 EP - 170 PB - AMA Verband für Sensorik und Messtechnik e.V. CY - Berlin AN - OPUS4-64061 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine A1 - Cano Murillo, Natalia A1 - Sawae, Y. A1 - Shinmori, H. A1 - Hashimoto, H. A1 - Aoyagi, A. A1 - Dobbelaar, E. T1 - Towards 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. GfT Tribologie-Fachtagung 2025 CY - Wernigerode, Germany DA - 29.09.2025 KW - Wasserstoff KW - Reibung KW - Verschleiß KW - Kolbenring KW - Dynamische Dichtung PY - 2025 VL - 09 SP - 1 EP - 4 AN - OPUS4-64314 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schaad, C. A1 - Tiebe, Carlo A1 - Groth, Katrina M. T1 - A Framework for Transforming Process Control System Data from a Hydrogen Fueling Station into HyCReD Data N2 - Reliability data for hydrogen infrastructure components is essential for developing Quantitative Risk Assessment (QRA) for these technologies, which in turn is necessary for a safer deployment and expansion of the hydrogen market. However, there is currently a lack of hydrogen component reliability data available for these systems, thus limiting the usefulness of insights obtained from these QRA. The Hydrogen Component Reliability Database (HyCReD) has been proposed as a tool for reliability data collection and as a source for future QRAs. In this paper, we develop a digital tool that automatically processes data coming from Process Control System (PCS) in a hydrogen fueling station, detects the relevant failure events for hydrogen systems during its operation, and then logs the event information into HyCReD. To build this tool, we first categorized the station components in hydrogen service, their specific failure modes, and the specific failure mechanisms that are relevant to a QRA. Then, we identified the data available in the station PCS and the methods available for diagnosing the relevant failure events. The resulting tool is divided into three steps: (1) PCS data collection through an API, (2) data analysis for the detection and diagnosis of new failure events, and (3) logging that event into HyCReD. Finally, we discuss the potential for expanding the detection and diagnosis to more complex failure modes present in a hydrogen fueling station. This digital tool is set for implementation and validation on an experimental hydrogen fueling site. The goal for this digital tool is to be applicable to every kind of hydrogen fueling station and to be extendable to similar hydrogen technologies. T2 - 35th European Safety and Reliability Conference (ESREL2025) and the 33rd Society for Risk Analysis Europe Conference (SRA-E 2025) CY - Stavanger, Norway DA - 15.06.2025 KW - Reliability data KW - Hydrogen safety KW - HyCReD KW - Hydrogen Component Reliability Database KW - Hydrogen fueling station KW - Hydrogen refuelling station KW - HRS PY - 2025 UR - https://rpsonline.com.sg/proceedings/esrel-sra-e2025/html/ESREL-SRA-E2025-P6264.html SN - 978-981-94-3281-3 DO - https://doi.org/10.3850/978-981-94-3281-3-procd SP - 2663 EP - 2670 PB - Research Publishing CY - Singapore AN - OPUS4-63532 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Eberwein, Robert A1 - Hajhariri, Aliasghar A1 - Otremba, Frank A1 - Camplese, Davide A1 - Scarponi, Giordano E. A1 - Cozzani, Valerio A1 - Seidlitz, Holger T1 - Repeatable testing of a cryogenic storage tank with variable insulation material in fire like conditions N2 - For decarbonizing the energy industry and transport, cryogenic energy carriers have great potential. The storage takes place in tanks with thermal super-insulations, which are in application for decades, but there is only limited knowledge about its behaviour in a fire scenario. This represents a major incident that may generate extraordinary loads on the tank and its insulation system, and that eventually lead to a sudden tank failure. This paper presents a test rig called the Cryogenic High Temperature Thermal Vacuum Chamber (CHTTVC), which can be used to test typical thermal superinsulation’s under cryogenic and fire-like conditions in parallel. The test method makes it possible to measure the heat flow through the thermal superinsulation over time and to investigate the degradation behaviour of the insulation within a test. In the paper results from the first tests are presented. T2 - 18th Cryogenics 2025, IIR Conference CY - Prague, Czech Republic DA - 07.04.2025 KW - LH2 KW - LNG KW - Fire KW - Insulation KW - Safety PY - 2025 DO - https://doi.org/10.18462/iir.cryo.2025.0007 SP - 205 EP - 210 CY - Prag AN - OPUS4-63740 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -