TY - CONF A1 - Grelle, Tobias T1 - Investigations on the Long-term Behavior of Metal Seals for Dual Purpose Casks N2 - In Germany, spent nuclear fuel and high active waste from reprocessing is stored in transport and storage containers with double lid systems that are equipped with metal seals completing the primary sealing barrier. The tasks of the Bundesanstalt für Materialforschung und -prüfung (BAM) within the interim storage licensing procedures ruled by the German Atomic Energy Act include the long-term safety evaluation of the container design regarding the permanently safe enclosure of the inventory. In order to generate a knowledge base for the safety evaluation, research regarding the long-term behavior of the critical components is performed. So far, the containers are licensed for an interim storage period of 40 years. However, due to significant delays in establishing a final repository, the required time span for interim storage is expected to increase significantly. Thus, a widespread investigation program is run to gain systematic data on the long-term behavior of the seals and to develop prediction models. Long-term seal investigations consider the development of their restoring seal force, their useable resilience and their achievable leakage rate caused by aging at temperatures ranging from room temperature up to 150 °C. This year, the total time span of the tests reaches 10 years. Furthermore, seal segments are aged at the selected temperatures for up to 300 days. From these segments additional information on the sealing behavior, changes of the seal contact and the material behavior is gained. This contribution deals with the current results of the long-term seal investigations at BAM. Furthermore, insights of the more in-depth component and material investigations of the metal seals with focus on the seal contact development are discussed and the ongoing work aiming for an analytical description of the thermo-mechanical aging effects on metal seals are presented. T2 - 19th International Symposium on the Packaging and Transportation of Radioactive Materials PATRAM 2019 CY - New Orleans, LA, USA DA - 04.08.2019 KW - Metal seal KW - Radioactive waste containers KW - Creep KW - Long-term behaviour PY - 2019 AN - OPUS4-49018 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaunich, Matthias T1 - Editorial N2 - Dear Readers, a new year started for all of us (as I write these lines, possibly it was already some time ago when these lines are finally available) and this is the time for the so-called New Year’s resolutions. Setting goals and changing our behavior as well in a private as in a professional context. For Scientists the resolutions may comprise tasks like finalizing a longago started publication, picking up the loose ends of an application for funding or just bringing the running projects in a greater structure. KW - Editorial KW - Polymer Testing PY - 2019 DO - https://doi.org/10.1016/j.polymertesting.2019.01.010 SN - 0142-9418 VL - 74 SP - A1 PB - Elsevier AN - OPUS4-47406 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weber, Mike A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Zencker, Uwe A1 - Völzke, Holger A1 - Schulze, Dietmar A1 - Probst, Ulrich T1 - Testing and Numerical Simulation of Elastomers - From Specimen Tests to Simulation of Seal Behavior under Assembly Conditions N2 - Due to delays in the siting procedure to establish a deep geological repository for spent nuclear fuel and high level radioactive waste as well as in construction of the already licensed Konrad repository for low and intermediate level radioactive waste, extended periods of interim storage become more relevant in Germany. BAM is involved in most of the cask licensing procedures and especially responsible for the evaluation of cask-related long-term safety issues. The long-term performance of elastomer seals for lid systems of transport and storage casks, whether used as auxiliary seals in spent fuel casks or as primary seals for low and intermediate level waste packages, is an important issue in this context. The polymeric structure of these seals causes a complex mechanical behavior with time-dependent sealing force reduction. The results of a comprehensive purpose-designed test program consisting of basic compression and tension tests as well as relaxation tests on unaged specimens of representative types of elastomers (fluorocarbon rubber (FKM) and ethylene propylene diene rubber (EPDM)) at different temperatures and strain rates are presented. They were used to identify the constitutive behavior and to obtain parameters for finite element material models provided by the computer code ABAQUS®. After estimating the influence of uncertainties such as Poisson’s ratio and friction coefficient by sensitivity analyses, the chosen parameters had to prove their suitability for the finite element simulation of the specimen tests themselves. Based on this preliminary work the simulation of a specific laboratory test configuration containing a typical elastomer seal with circular cross section is presented. The chosen finite element material model and the implemented parameters had to show that they are able to represent not only the specimen behavior under predominantly uniaxial load but also the more complex stress states in real components. Deviations between the measured and calculated results are pointed out and discussed. For the consideration of long-term effects in the simulation of elastomer behavior, test results of aged specimens are needed. First information about a new test program, started recently and planned to provide these data, are given. T2 - ASME 2017 Pressure Vessels & Piping Conference (PVP2017) CY - Waikoloa, Hawaii, USA DA - 16.07.2017 KW - Time dependent effects KW - Low temperature behavior KW - Elastomeric seals KW - Aging KW - Simulation KW - Testing PY - 2017 SN - 978-0-7918-5802-8 VL - 7 SP - Article UNSP V007T07A035, 1 EP - 8 AN - OPUS4-41841 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Low temperature properties of elastomer seals - Comparison between purely static and partially released seals - N2 - Rubber is widely used as sealing material in various applications. In many fields the function of seal materials at low temperatures is necessary. Therefore the understanding of failure mechanisms that lead to leakage at low temperatures is of high importance. It is known that the material properties of rubbers are strongly temperature dependent. At low temperatures this is caused by the rubber-glass transition (abbr. glass transition). During continuous cooling the material changes from rubber-like entropy-elastic behaviour to stiff energy-elastic behaviour, that allows nearly no strain or retraction, due to the glass transition. Hence rubbers are normally used above their glass transition but the minimum working temperature limit is not defined precisely, what can cause problems during application. Therefore the lower operation temperature limit of rubber seals should be determined in dependence of the material properties. In the past we investigated the material properties and sealing behaviour of elastomeric seals at low temperatures. Additionally we started to study the effect of a small partial release of elastomer seals at low temperatures. To study the influence of dynamic events on seal performance and to enhance the understanding of occurring seal failure, a setup for a fast partial seal release was designed. In this contribution we focus on the correlation of material properties and component behaviour under different application conditions. It is desired to widen the understanding of the process of seal failure at low temperature. T2 - 12. Kautschuk Herbst Kolloquium CY - Hannover, Germany DA - 22.11.2016 KW - Seal behaviour KW - Partial release KW - Low temperature KW - Leakage rate PY - 2016 AN - OPUS4-38500 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weber, Mike A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Zencker, Uwe A1 - Völzke, Holger A1 - Schulze, Dietmar T1 - Testing and numerical simulation of elastomeric seals under consideration of time dependent effects N2 - Due to delays in the siting procedure to establish a deep geological repository for spent nuclear fuel and high level waste and in construction of the already licensed Konrad repository for low and intermediate level waste, extended periods of interim storage will become more relevant in Germany. BAM is involved in most of the cask licensing procedures and is responsible for the evaluation of cask-related long-term safety issues. Elastomeric seals are widely used as barrier seals for containers for low and intermediate level radioactive waste. In addition they are also used as auxiliary seals in spent fuel storage and transportation casks (dual purpose casks (DPC)). To address the complex requirements resulting from the described applications, BAM has initiated several test programs for investigating the behavior of elastomeric seals. These include experiments concerning the hyperelastic and viscoelastic behavior at different temperatures and strain rates, the low temperature performance down to -40°C, the influence of gamma irradiation and the aging behavior. The first part of the paper gives an overview of these tests, their relevant results and their possible impact on BAM’s work as a consultant in the framework of approval and licensing procedures. The second part presents an approach of the development of a finite element model using the finite element code ABAQUS®. The long-term goal is to simulate the complex elastomeric behavior in a complete lid closure system under specific operation and accident conditions. T2 - ASME 2016 Pressure Vessels & Piping Conference (PVP2016) CY - Vancouver, BC, Canada DA - 17.07.2016 KW - Elastomeric seals KW - Testing KW - Low temperature behavior KW - Aging KW - Simulation KW - Time dependent effects PY - 2016 SN - 978-0-7918-5045-9 VL - 7 SP - Paper 63192, 1 EP - 10 AN - OPUS4-37046 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zaghdoudi, M. A1 - Kömmling, Anja A1 - Böhning, Martin A1 - Jaunich, Matthias T1 - Ageing of elastomers in air and in hydrogen environment - A comparative study N2 - EPDM, HNBR and FKM materials were exposed at 150 ◦C to air under atmospheric pressure and to hydrogen at 50 bar for different ageing times. All measurements after hydrogen exposure were conducted on samples in degassed condition to assess irreversible effects resulting from that exposure and to compare them to those after ageing in air. Density, hardness, tensile properties, compression set, and hydrogen permeability of all samples were analysed. In both ageing environments, HNBR exhibited the most significant changes of material properties. However, for both EPDM and HNBR, considerably less severe ageing effects were observed under hydrogen in comparison to ageing in air. On the other hand, FKM showed about the same low level of deterioration in both ageing environments but exhibited poor resistance against damage due to rapid gas decompression in hydrogen environment that can lead to seal failure. The obtained results may serve as a guidance toward a better understanding for design and utilisation of elastomeric materials in future hydrogen infrastructure components. KW - Rapid gas decompression KW - Condensed matter physics KW - Hydrogen KW - Sustainability and the environment KW - Rubber sealing KW - Renewable energy PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597417 DO - https://doi.org/10.1016/j.ijhydene.2024.03.053 SN - 0360-3199 SN - 1879-3487 VL - 63 SP - 207 EP - 216 PB - Elsevier CY - Oxford AN - OPUS4-59741 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zaghdoudi, Maha A1 - Weber, Mike A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Numerical Modelling of Compression Stress Relaxation and Compression Set of Elastomer O-Ring During Aging N2 - Elastomer seals are used in many industrial applications due to their excellent mechanical properties at a wide range of temperatures. Their high versatility and recovery potential under several load conditions make them well suitable for the application in containers designed for transport, storage and/or disposal of radioactive materials. In containers for low and intermediate level radioactive waste, elastomer seals are used as barrier seals, and as auxiliary seals in storage and transportation casks (dual purpose casks) for heat generating radioactive waste, such as spent fuel and high-level waste. While a seal exchange at defined intervals is typical in many conventional applications, it is impossible or at least hard to perform when principles of minimization of radiation exposure have to be considered and prohibit an unnecessary cask handling. An extensive knowledge of the change of the elastomer’s properties during aging and the availability of reliable end-of-lifetime criteria to guarantee the permanent safe enclosure of the radioactive material is mandatory. As BAM is involved in most of the national cask licensing procedures and in the evaluation of cask-related long-term safety issues, great efforts have been already made and are still planned to scientifically support this task. Compression stress relaxation and compression set were identified as key indicators of elastomer long-term performance and quantitatively investigated in comprehensive test programs. Among other representative types of elastomers, specimens made from ethylene propylene diene rubber (EPDM) were tested before, during and after aging to capture the most important of their complex mechanical properties. In the presented study, exemplary results were used to simulate the compression stress relaxation and the compression set of elastomer O-rings during aging. Regarding the influence of temperature, the time-temperature superposition principle is applied in the relaxation analysis of elastomer O-rings. The proposed model is implemented in the commercial finite element software ABAQUS/Standard® [1] with a sequential temperature displacement coupling. Numerical results match the experimental compression stress relaxation measurements well. The prediction of compression set values after long-term aging shows a relatively good agreement with the experimental results. Nevertheless, all input parameters derived from the specimen tests, additional assumptions concerning boundary conditions and modeling strategy are discussed with regard to the identified slight discrepancies. The possibility to extend the finite element model to represent the O-ring seal’s ability to recover after a (fast) partial release is taken into account. T2 - ASME 2020 Pressure Vessels & Piping Conference (PVP2020) CY - Online meeting DA - 03.08.2020 KW - Compression Set KW - O-ring KW - Simulation KW - Sequential analysis KW - Ageing KW - stress relaxation PY - 2020 SN - 978-0-7918-8388-4 DO - https://doi.org/10.1115/PVP2020-21270 SP - PVP2020-21270 PB - ASME AN - OPUS4-51490 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Subramani Bhagavatheswaran, E. A1 - Wießner, S. A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Einfluss der Alterung auf dichtungsrelevante Eigenschaften von FKM-, VMQ- und EPDM-Elastomeren N2 - Da Elastomere in vielfältigen Dichtungsanwendungen eingesetzt werden und dabei teilweise großen Einfluss auf die Funktionsfähigkeit und Sicherheit haben, ist der Einfluss der Alterung auf dichtungsrelevante Eigenschaften relevant. Eine strukturierte Untersuchung des Einflusses von verschiedenen Mischungsrezepturen auf die Bauteileigenschaften, das Alterungsverhalten und die Funktion wird vorgestellt. T2 - Technomer 2017 CY - Chemnitz, Germany DA - 09.11.2017 KW - Dichtung KW - Alterung KW - Struktur-Eigenschaftsbeziehung KW - Elastomer PY - 2017 SN - 978-3-939382-13-3 VL - 2017 SP - 41 EP - 41 AN - OPUS4-42844 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wollschläger, Nicole A1 - Häusler, Ines A1 - Ortel, Erik A1 - Hodoroaba, Vasile-Dan A1 - Palasse, L. A1 - Dirscherl, K. T1 - Characterization of porous, TiO2 nanoparticle films using on-axis TKD in SEM – a new nano-analysis tool for a large-scale application N2 - A combined methodical approach is tested with respect to the characterization of the inner structure of porous TiO2 layers as typically used in modern dye sensitized solar cells (DSSC). Their performance is directly linked to the surface area of the pore network. The micrometer thick layer employed was manufactured by screen-printing of a starting TiO2 powder constituted of shape-controlled, bipyramidal anatase nanoparticles on FTO/glass substrates. The analytical methods exploited in our study are Focused Ion Beam (FIB) slicing followed by 3D reconstruction as well as the new approach transmission Kikuchi diffraction (TKD) technology in the scanning electron microscope (SEM). Size and shape distribution of the TiO2 NPs within the layer can be extracted. SEM in transmission mode and atomic force microscopy (AFM) have been used to verify the dimensional data obtained by the new combined methodical approach. Its analytical benefits but also the challenges and limitations are highlighted. KW - TiO2 KW - TKD KW - Particle size distribution KW - Nanoparticles KW - Porous film PY - 2017 UR - https://www.cambridge.org/core/services/aop-cambridge-core/content/view/8A8B29335A2F4D0CB6922F6F5A19C5DC/S1431927617003397a.pdf/characterization_of_porous_tio2_nanoparticle_films_using_onaxis_tkd_in_sem_a_new_nanoanalysis_tool_for_a_largescale_application.pdf DO - https://doi.org/10.1017/S1431927617003397 VL - 23 IS - S1 (July) SP - 542 EP - 543 PB - Cambridge University Press CY - New York, NY, U.S.A. AN - OPUS4-41924 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Zaghdoudi, M. A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar ED - Altenbach, H. ED - Hitzler, L. ED - Johlitz, M. ED - Merkel, M. ED - Öchsner, A. T1 - Analysis of Heterogeneous Ageing of HNBR O-Rings N2 - Abstract Hydrogenated nitrile butadiene rubber (HNBR) elastomer was thermo-oxidatively aged at different temperatures up to 150 °C. Fourier transform infrared spectroscopy (FTIR), compression stress relaxation (CSR) and international rubber hardness degree (IRHD) microhardness were used to characterise the chemo-mechanical changes of HNBR O-rings during thermo-oxidative ageing. FTIR shows the development of carbonyl, methyl and ester groups but the nitrile content was not affected by ageing. The effect of sample geometry during CSR was investigated. CSR data were converted through integrated kinetic laws. The conversion has proven its sensibility to detect heterogeneous ageing. This was confirmed by the IRHD measure-ments across the section of O-rings. The influence of compression during ageing was assessed through IRHD measurements across the section of compressed and uncom-pressed aged O-rings. The DLO effect was more pronounced in compressed O-rings. By applying the model of Wise et al., theoretical IRHD and oxidation profiles were determined on the basis of IRHD experimental data of compressed O-rings. Good agreements between the experimental and the theoretical IRHD profiles in the core region were obtained. However, near the edge, the theoretical IRHD values were overestimated. KW - Ageing KW - Rubber seals KW - Stress relaxation KW - Modelling PY - 2024 SN - 978-3-031-49042-2 DO - https://doi.org/10.1007/978-3-031-49043-9 SN - 1869-8433 SP - 331 EP - 348 PB - Springer Nature CY - Cham, Switzerland AN - OPUS4-59769 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beckmann, Jörg T1 - Photolytically and Thermally Initiated Destruction on the Stability of (Ultra)High Molecular Polyethylene N2 - THz and mid IR spectroscopy of high-molecular PE (HMW) and ultra high-molecular PE (UHMW) reveals modifications of the molecular structure. Characteristic absorption bands are changed if the two materials are exposed by γ-Co60 radiation up to 600 kGy and subsequently stored at an annealing temperature of 398 K until for 729 days. UHMW-PE and HMW-PE behave differently during the ageing process because of their molecular weight and inherent structure distinctions. The spectroscopic data offer characteristic absorption bands, which have been used to describe the complete ageing process in more detail. For instance, the integral absorption in the B1u THz-region can be used to describe quantitatively the reduction of crystallinity. The formation of trans vinylene unsaturation and the decay of vinyl during ageing can be observed in detail in the mid IR range. T2 - 9th International Workshop on Terahertz Technology and Applications CY - Kaiserslautern, Germany DA - 03.03.2020 KW - Degradation KW - MID IR Spectroscopy PY - 2020 AN - OPUS4-50555 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Ageing and lifetime prediction of O-ring seals made of HNBR, EPDM and FKM N2 - BAM is the federal institute for materials research and testing in Germany. One of our tasks is to evaluate the safety of casks designed for transport and/or storage of radioactive waste. As elastomeric seals are used in the containers as safety-relevant parts, it is our goal to be able to evaluate the service lifetime of the seals with regard to the requirements for long-term safety (40 years and more) of the containers. For this reason, an accelerated ageing programme with selected rubbers often used for seals (HNBR, EPDM and FKM) was started. Ageing was performed at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) for up to 2 years. For assessing properties related to the sealability, O-rings were aged in compression by 25 % (corresponding to the compression during service) between plates. For comparison, uncompressed O-rings were aged as well. The aged materials were characterized with conventional polymer analysis methods such as hardness and tensile tests, but also with more seal-specific methods such as compression stress relaxation (CSR, reflecting the loss of sealing force of a compressed seal over time), and compression set (CS, representing the recovery behaviour of a seal after release from compression). CS is chosen as the property for lifetime prediction as it is both sensitive to degradation and related to the seal performance. CS data is extrapolated to 60 °C, which yields lifetimes of approximately 5 years for HNBR and 64 years for EPDM for a criterion of 85 % CS respectively, and approx. 40 years for FKM for a criterion of 65 % CS (the highest value measured so far). T2 - 12. Kautschuk Herbst Kolloquium CY - Hanover, Germany DA - 22.11.2016 KW - Rubber KW - Compression set KW - Extrapolation KW - Degradation PY - 2016 SN - 9783981407648 VL - 2016 AN - OPUS4-38483 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grelle, Tobias A1 - Probst, Ulrich A1 - Jaunich, Matthias A1 - Skrotzki, Birgit A1 - Wolff, Dietmar T1 - Creep investigations on aluminum seals for application in radioactive waste containers N2 - In Germany spent nuclear fuel and high level radioactive waste is stored in interim storage containers with double lid systems. Those lids are equipped with metal seals (e.g. Helicoflex®) that ensure the safe enclosure of the inventory. The used metal seals consist of three components as can be seen in the cross-sectional view in Figure 1. The innermost part is a helical spring that is surrounded by an inner jacket made of stainless steel. The outer jacket that is made of a softer material which in case of assembly in the aforementioned storage containers is silver or aluminum (i.e. Al 99.5). During application the seal is compressed and due to the restoring force of the helical spring, the outer jacket is plastically deformed and adapts to the sealing surface. Hence, leakage paths are closed and the sealing function is generated. In Germany the above-mentioned containers are licensed for up to 40 years of interim storage, which in case extended storage becomes necessary before a final repository is available will have to be extended to even longer periods. Therefore, the evaluation of the long-term behavior of the seals is necessary, taking into account storage conditions, decay heat and possible mechanical loads as well. At Bundesanstalt für Materialforschung und –prüfung (BAM) long-term investigations are being conducted in which seals are assembled in test flanges and aged at temperatures ranging from room temperature to 150°C for accelerated aging. The aged seals are tested semi-annually (after the first 6 months in which the seals are tested more frequently) regarding the sealing performance, the remaining seal force, and the useable resilience upon decompression. Results of these investigations have been published over the past years (e.g. Grelle, Wolff, Probst, Jaunich, & Völzke, 2017; Völzke, Wolff, Probst, Nagelschmidt, & Schulz, 2014). It was found that the seal force and the useable resilience decrease with time and temperature, which is in agreement with the result of other studies (Sassoulas et al., 2006; Wataru et al., 2016) as well. Geometry change of the outer jacket has been identified as the main reason for this seal behavior. At the prevailing operating temperatures and stresses the aluminum is subjected to creep deformation leading to a thinning of the outer jacket. Since the seal groove depth remains unchanged the helical spring expands, which in turn leads to a decrease of the generated spring and seal force. Although the main reason for the change of seal parameters over time and temperature is known, a detailed characterization of the seal behavior and a reliable prediction of the parameter development for aging times that exceed the experimental time frame have not been possible, yet. For deeper understanding of the aging processes, an Investigation program, which is covered in this contribution, is conducted at Bundesanstalt für Materialforschung und –prüfung (BAM) that focusses on the behavior of the aluminum jacket and its influence on the long-term sealing performance. The program investigates properties of material samples as well as the behavior of the seal as a component. Original sheet material of the same aluminum that is used for manufacturing of the seals is investigated in compression creep tests. For this, a DMA (dynamic mechanical analysis) machine is employed (here used for static tests) that allows for a measurement of the specimens deformation under forces of up to 500 N. The advantage of this method is that the original material can be tested in the same shape as used for the seals which is 0.5 mm thick sheet material. For investigation of tensile creep standard specimens are used, that were machined from surrogate material of the same composition and annealing condition. Furthermore, aluminum seals that are cut into smaller segments are assembled in flanges and placed in heating chambers at temperatures ranging from 23°C to 150°C. After different periods of time from 3 days to 300 days the segments are taken out of the flanges and are investigated, thus giving information on different states of aging. Measurements of the development of the seal contact width and the aluminum jacket thickness are done with an optical microscope. Further investigations on the segments will include metallography and hardness measurements. From the detailed material and component behavior including the results of the long-term seal force and useable resilience investigations a better understanding of the overall seal behavior can be gained. The aim is to contribute to the development of material models and analytical approaches for the prediction of the sealing behavior in dependence of time and temperature. T2 - International Conference on Aluminum Alloys CY - Montreal, Canada DA - 17.06.2018 KW - Metal seal KW - Creep KW - Long-term behavior PY - 2018 SN - 978-1-926872-41-4 SP - 1 EP - 2 AN - OPUS4-45844 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dhamo, Lorena A1 - Carulli, F. A1 - Nickl, Philip A1 - Wegner, Karl David A1 - Hodoroaba, Vasile-Dan A1 - Würth, Christian A1 - Brovelli, S. A1 - Resch-Genger, Ute T1 - Efficient luminescent solar concentrators based on environmentally friendly Cd-free ternary AIS/ZnS quantum dots N2 - Luminescent solar concentrators (LSC) allow to obtain renewable energy from building integrated photovoltaic systems. As promising efficient and long-term stable LSC fluorophores semiconductor nanocrystals like Quantum dots (QDs) with size and composition tunable optoelectronic properties have recently emerged. The most popular II/VI or IV/VI semiconductor QDs contain, however, potentially hazardous cadmium or lead ions, which is a bottleneck for commercial applications. A simple aqueous based, microwaveassisted synthesis for environmentally friendly and highly emissive AgInS2/ ZnS QDs is developed using 3-mercaptopropionic acid (MPA) and glutathione (GSH) and their incorporation into polylaurylmethacrylate (PLMA) polymer slabs integrable in LSC devices (10.4 × 10.4 × 0.2 cm3, G = 12.98). With this simple approach, optical power efficiencies (OPE) of 3.8% and 3.6% and optical quantum efficiencies (OQE) of 24.1% and 27.4% are obtained, which are among the highest values yet reported. KW - Solar energy KW - Solar concentrator KW - Quantum dots KW - Advanced material KW - Quantum yield PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529735 DO - https://doi.org/10.1002/adom.202100587 SN - 2195-1071 SN - 0935-9648 VL - 9 IS - 17 SP - 1 EP - 8 PB - Wiley-VCH CY - Weinheim AN - OPUS4-52973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Agudo Jácome, Leonardo A1 - Nolze, Gert A1 - Roohbakhshan, Farshad A1 - Fedelich, Bernard A1 - Olbricht, Jürgen A1 - Skrotzki, Birgit T1 - Cyclic operation performance of 9-12% Cr ferritic-martensitic steels part 2: Microstructural evolution during cyclic loading and its representation in a physically-based micromechanical model N2 - The current competitive situation on electricity markets forces conventional power plants into cyclic operation regimes with frequent load shifts and starts/shutdowns. In the present work, the cyclic mechanical behavior of ferritic-martensitic 9-12 % Cr steels under isothermal and thermomechanical loading was investigated for the example of grade P92 material. A continuous softening was observed under all loading conditions. The introduction of hold periods to the applied cycles reduced material lifetime, with most prominent effects at technologically relevant small strain levels. The microstructural characterization reveals a coarsening of the original “martensitic” lath-type microstructure to a structure with polygonal subgrains and reduced dislocation density. The microstructural data forms the input for a physically-based modelling approach. T2 - 45. MPA-Seminar CY - Leinfelden-Echterdingen, Germany DA - 01.10.2019 KW - Tempered Martensite Ferritic Steels KW - P92 KW - TEM KW - EBSD KW - Micromechanical model PY - 2019 SP - 80 EP - 85 PB - MPA (Materialprüfungsanstalt Universität Stuttgart) CY - Stuttgart AN - OPUS4-50052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sachse, René A1 - Hodoroaba, Vasile-Dan A1 - Kraehnert, R. A1 - Hertwig, Andreas T1 - Multilevel effective material approximation for modeling ellipsometric measurements on complex porous thin films N2 - Catalysts are important components in chemical processes because they lower the activation energy and thus determine the rate, efficiency and selectivity of a chemical reaction. This property plays an important role in many of today’s processes, including the electrochemical splitting of water. Due to the continuous development of catalyst materials, they are becoming more complex, which makes a reliable evaluation of physicochemical properties challenging even for modern analytical measurement techniques and industrial manufacturing. We present a fast, vacuum-free and non-destructive analytical approach using multi-sample spectroscopic ellipsometry to determine relevant material parameters such as film thickness, porosity and composition of mesoporous IrOx–TiOy films. Mesoporous IrOx–TiOy films were deposited on Si wafers by sol–gel synthesis, varying the composition of the mixed oxide films between 0 and 100 wt%Ir. The ellipsometric modeling is based on an anisotropic Bruggeman effective medium approximation (a-BEMA) to determine the film thickness and volume fraction of the material and pores. The volume fraction of the material was again modeled using a Bruggeman EMA to determine the chemical composition of the materials. The ellipsometric fitting results were compared with complementary methods, such as scanning electron microscopy (SEM), electron probe microanalysis (EPMA) as well as environmental ellipsometric porosimetry (EEP). KW - Electrochemical catalysts KW - Mixed metal oxide KW - Multi-sample analysis KW - Spectroscopic ellipsometry KW - Thin mesoporous films PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551026 DO - https://doi.org/10.1515/aot-2022-0007 SN - 2192-8584 SN - 2192-8576 VL - 11 IS - 3-4 (Topical issue: Ellipsometry) SP - 137 EP - 147 PB - De Gruyter CY - Berlin AN - OPUS4-55102 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zaghdoudi, Maha A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Understanding the recovery behaviour and the degradative processes of EPDM during ageing N2 - Recovery is an important measure for seal applications representing to which extent the elastomer regains its initial shape after deformation and release of an applied force. Compression set (CS) indicates the degree of recovery. Ethylene propylene diene rubber (EPDM) was aged at 75 ◦C, 100 ◦C, 125 ◦C and 150 ◦C for different ageing times up to five years and compression set measurements were performed at different times after disassembly and after additional tempering. Short- and long-term recovery up to one year after release for samples aged at 125 ◦C and 150 ◦C was also studied. To assess the curvature in the Arrhenius diagram that may occur due to non-sufficiently aged specimens, a degradation-rate based model was fitted to the CS data after tempering. For each ageing temperature, two decay fit functions were proposed, each with an activation energy and a corresponding degradative process. The influence of ageing on the leak-tightness after fast small partial release is investigated and estimated through the analysis of the shift factors from time temperature superposition (TTS) of CS measurements at different times after disassembly. Shift factors of CS measurement after 1 s and after additional tempering are in good agreement. KW - Compression set KW - Ageing KW - Recovery KW - Degradative processes KW - Leakage rate PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573699 DO - https://doi.org/10.1016/j.polymertesting.2023.107987 SN - 0142-9418 VL - 121 SP - 107987 PB - Elsevier Ltd. AN - OPUS4-57369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zaghdoudi, Maha A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Oxidative ageing of elastomers: Experiment and modelling N2 - During an extensive test programme at the Bundesanstalt für Materialforschung und prüfung, material property changes of EPDM O-rings were investigated at different ageing times and two ageing temperatures of 125∘C and 150∘C. To exclude possible diffusion-limited oxidation (DLO) effects that can distort the data, IRHD microhardness measurements were taken over the cross section of compressed O-rings. Continuous stress relaxation measurements were taken on samples free of DLO effects. The additional effect of physical processes to irreversible chemical ones during a long-term thermal exposure is quantified by the analysis of compression set measurements under various test conditions. By combining the different experimental methods, characteristic times relative to the degradation processes were determined. On the basis of experimental data, a microphysically motivated model that takes into account reversible and irreversible processes was developed. The parameter identification strategy of the material model is based on our experimental investigations on homogeneously aged elastomer O-rings. The simulated results are in good agreement with the experiments. KW - Compression stress relaxation KW - Compression set KW - IRHD microhardness KW - Modelling PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545910 DO - https://doi.org/10.1007/s00161-022-01093-9 SN - 1432-0959 SP - 1 EP - 9 PB - Springer CY - Berlin AN - OPUS4-54591 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaunich, Matthias A1 - Goral, Milan A1 - Wolff, Dietmar A1 - Völzke, Holger ED - Krüssenberg, A. T1 - Overview of metal seal tests performed at BAM and implications for extended interim storage N2 - The investigation of the long-term performance of sealing systems employed in containers of radioactive waste and spent nuclear fuel is one research focus area for division 3.4 \Safety of Storage Containers" at the Bundesanstalt für Materialforschung und -prüfung. The behaviour of metallic seals, which are employed in interim storage casks for spent nuclear fuel and high active waste, over time is of high importance for ensuring safe enclosure. Therefore, investigations on these systems were started at BAM to get a general understanding of the relevant processes. Our investigations comprise investigations on different parameters which influence the seal Performance and the main part is focussed on the time and temperature dependent behaviour. Our aim is to understand the longterm behaviour of the sealing systems for evaluation of their performance during possible extended interim storage and subsequent transportation. In this contribution an overview of the performed tests and their respective results is given. A focus lies on a comparison between seals with large torus diameter in comparison to small diameters. T2 - Safety of Extended Dry Storage of Spent Nuclear Fuel SEDS2020: International online-workshop CY - Online meeting DA - 03.06.2020 KW - Metal seal KW - Seal performance KW - Long-term investigation KW - Ageing PY - 2020 DO - https://doi.org/10.3139/124.200071 SN - 0932-3902 VL - 85 IS - 6 SP - 440 EP - 443 PB - Carl Hanser Verlag CY - München AN - OPUS4-51833 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Subramani Bhagavatheswaran, E. A1 - Wießner, S. A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Aging study and electrical resistance based stress-monitoring of rubber seals N2 - Elastomer seals are widely used as barrier seals in containers for low and intermediate level radioactive waste. In addition, they are also used in waste fuel storage and transportation casks as auxiliary seals. Depending on the area of use, the rubber materials have to demonstrate proper sealing performance with respect to mechanical, thermal and environmental conditions as well as irradiation during the entire operation period. A fundamental understanding of the structure property relationship and their changes during aging can help to evaluate the long-term sealing performance. In the present study, specific materials are investigated to study the structure-property and seal performance-correlation. Fluoro-elastomer (FKM), silicone rubber (VMQ) and ethylene propylene diene rubber (EPDM) were chosen as base rubbers. Comparable mechanical properties for these seals, especially in terms of a comparable compression behavior were achieved by careful control of base rubber formulation, i.e., by opting for the right filler and its concentration, amount of crosslinking chemicals, and with the assistance of process oils. Moreover, with the same rubber, similar mechanical properties were achieved by varying the filler concentration and crosslinking degree, which shall enable to correlate the particular influence on the structure property dependency of the seals in detail. The materials are investigated under pristine and aged conditions to evaluate the influence of aging, e.g. on the stress relaxation or recovery behavior. These values appear to be suitable parameters to judge the expected sealing performance. Due to the electrically conducting nature of some fillers used to reinforce rubbers (such as carbon blacks, carbon nanotubes (CNTs), Graphene, etc.) it is possible to obtain current information about mechanical and visco-elastic properties by monitoring the electrical conductivity or resistivity. A simple relation that relates electrical resistance with mechanical stress was derived and the stress values were theoretically predicted from the electrical resistance values, which showed good correlation with experimental results. T2 - 192nd Technical meeting of the ACS Rubber Division CY - Cleveland, OH, USA DA - 09.10.2017 KW - Seal KW - Rubber KW - Degradation KW - Structure-property relationship KW - Ageing PY - 2017 VL - 2017 SP - 1 EP - 25 AN - OPUS4-42849 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jürgens, Maria A1 - Olbricht, Jürgen A1 - Fedelich, Bernard A1 - Skrotzki, Birgit T1 - Low Cycle Fatigue and Relaxation Performance of Ferritic–Martensitic Grade P92 Steel N2 - Due to their excellent creep resistance and good oxidation resistance, 9–12% Cr ferritic–martensitic stainless steels are widely used as high temperature construction materials in power plants. However, the mutual combination of different loadings (e.g., creep and fatigue), due to a “flexible” operation of power plants, may seriously reduce the lifetimes of the respective components. In the present study, low cycle fatigue (LCF) and relaxation fatigue (RF) tests performed on grade P92 helped to understand the behavior of ferritic–martensitic steels under a combined loading. The softening and lifetime behavior strongly depend on the temperature and total strain range. Especially at small strain amplitudes, the lifetime is seriously reduced when adding a hold time which indicates the importance of considering technically relevant small strains. KW - Ferritic–martensitic steel KW - P92 KW - Low cycle fatigue KW - Relaxation fatigue KW - Cyclic softening PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473905 DO - https://doi.org/10.3390/met9010099 VL - 9 IS - 1 SP - 99, 1 EP - 25 PB - MDPI AN - OPUS4-47390 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Kömmling, Anja T1 - Alterung und Lebensdauervorhersage von O-Ring-Dichtungen T1 - Aging and lifetime prediction of O-ring seals N2 - Für Anwendungen, bei denen Elastomerdichtungen ihre Dichtheit über sehr lange Zeiträume (z. B. Jahrzehnte) behalten müssen, ohne dass ein Austausch praktikabel wäre, ist es nötig, die Lebensdauer solcher Dichtungen zuverlässig bestimmen zu können. Aus diesem Grund wurden Alterungsversuche an O-Ring-Dichtungen sowie Flachproben auf Basis von hydriertem Acrylnitril-Butadien-Kautschuk (HNBR), Ethylen-Propylen-Dien-Kautschuk (EPDM) und Fluorkautschuk (FKM) über bis zu zwei Jahre bei mehreren Temperaturen durchgeführt. Zur Untersuchung der auftretenden Eigenschaftsveränderungen wurden u. a. Härtemessungen, Zugversuche, dynamisch-mechanische und thermogravimetrische Analysen durchgeführt. Zur Beurteilung des Relaxations- und Rückstellverhaltens der alternden Dichtungen wurden außerdem Druckspannungsrelaxations- und Druckverformungsrestmessungen durchgeführt. Darüber hinaus wurde die Leckagerate gemessen, um ein Versagen der Dichtung zu detektieren. Durch die Untersuchung der gealterten Proben wurden sowohl die auftretenden Eigenschaftsveränderungen charakterisiert wie auch die damit zusammenhängenden Alterungsmechanismen diskutiert. Anhand der großen Datenmenge aus Ergebnissen von verschiedenen Untersuchungsmethoden, die für mehrere Alterungszeiten und -temperaturen durchgeführt wurden, sollte zusätzlich die günstigste Vorgehensweise für Lebensdauervorhersagen ermittelt werden. Dies beinhaltete auch die Bestimmung eines Lebensdauerkriteriums, das mit dem Auftreten von Leckage und damit dem Versagen der Dichtung zusammenhängt. Hinsichtlich der Eigenschaftsänderungen und Alterungsmechanismen wurde beim HNBR eine starke Versprödung aufgrund dominanter Vernetzungsreaktionen während der Alterung festgestellt. Diese resultierten auch darin, dass die Sauerstoffpermeabilität abnahm, so dass der Sauerstofftransport ins Innere der Probe (hauptsächlich bei den dickeren O-Ringen) behindert wurde. Dies führte dazu, dass diffusionsbegrenzte Oxidationseffekte (DLO-Effekte) auftraten, d. h. dass das Probeninnere weniger stark alterte als oberflächennahe Bereiche. Während der Alterung von EPDM traten sowohl Kettenspaltungen wie auch Vernetzungsreaktionen auf, was sich vor allem in einer Verschlechterung der Zugeigenschaften und einer Abnahme der Druckkraft sowie in einem steigenden Druckverformungsrest äußerte. Bei sehr stark gealterten Proben dominierten ebenfalls Vernetzungsreaktionen, was sich auch in deutlichen DLO-Effekten äußerte. Aufgrund seiner ausgeprägten Oxidations- und Hochtemperaturbeständigkeit wies FKM vergleichsweise geringe Degradationserscheinungen auf. Nur mit Druckspannungsrelaxation und Druckverformungsrest waren nennenswerte Änderungen ersichtlich. Messungen der statischen Leckagerate ergaben, dass die O-Ringe erst bei sehr weit fortgeschrittener Degradation undicht wurden und bis zu diesem Zeitpunkt kein allmählicher Anstieg der Leckagerate beobachtet werden konnte. Aus diesem Grund wurden Leckagemessungen mit einem modifizierten Versuchsaufbau durchgeführt, bei dem die Dichtung während der Messung leicht entlastet wird. Da dieser Test eine dynamische Rückstellung der Dichtung erfordert und damit höhere Ansprüche an die Dichtung stellt, wurde am geprüften EPDM-O-Ring ein früheres Versagen beobachtet. Der entsprechende Alterungszeitpunkt wurde als Versagenszeitpunkt definiert. Dieser wurde anhand der Daten verschiedener Messmethoden mit dem Degradationszustand korreliert und entspricht beispielsweise einem Druckverformungsrest von 80 %. Auf der Grundlage dieses Kriteriums konnten Lebensdauern mittels Zeit-Temperatur-Verschiebung bestimmt werden. Im Rahmen dieser Arbeit wurden zahlreiche Erkenntnisse darüber gewonnen, worauf bei beschleunigten Alterungsversuchen und Lebensdauerprognosen von O-Ringen zu achten ist und welche Fehlerquellen vermieden werden sollten. Dies wird zusammen mit Empfehlungen für eine bestmögliche Versuchsdurchführung ausführlich diskutiert. N2 - In some applications, elastomer seals have to remain leak tight over extended time periods (up to several decades) as an exchange of the seals is not practical. Therefore, it is necessary to be able to predict the lifetime of such seals reliably. For this reason, ageing experiments with O-rings and sheets based on hydrogenated acrylonitrile butadiene rubber (HNBR), ethylene propylene diene rubber (EPDM) and fluorocarbon rubber (FKM) were performed over up to two years at different temperatures. For investigating the changes of material properties during ageing, measurements of i.a. hardness and tensile behaviour as well as dynamic-mechanical and thermogravimetric analyses were conducted. For assessing the relaxation and recovery behaviour of the ageing seals, compression stress relaxation and compression set experiments were performed. Furthermore, leakage rate was measured to detect seal failure. By examining the aged samples, both the property changes and the responsible degradation mechanisms were characterised. Additionally, the most suitable approach for lifetime predictions should be determined using the large database of results from different test methods performed at several ageing times and temperatures. This included identifying an end-of-lifetime criterion that correlates with leakage and thus seal failure. Regarding the property changes and degradation mechanisms of HNBR, a pronounced embrittlement was observed due to dominant crosslinking reactions during ageing. These also resulted in a decrease of oxygen permeability, leading to a reduction of the oxygen transport into the interior sample (mainly of the thicker O-rings). This resulted in diffusion-limited oxidation effects (DLO effects), meaning that the interior of the sample aged less strongly than regions close to the surface. During ageing of EPDM, both chain scission and crosslinking occurred, which became noticeable in deteriorated tensile properties and decreased compression force as well as an increase of compression set. For strongly aged samples, crosslinking dominated as well and also led to pronounced DLO effects. Due to its excellent heat and oxidative stability, FKM exhibited comparatively minor degradation effects. Only compression stress relaxation and compression set showed notable changes. Measurements of static leakage rate revealed that O-rings became untight only after advanced degradation and that no gradual increase of leakage rate could be observed before failure. For this reason, additional leakage measurements were performed using a modified experiment that enabled a small decompression of the seal during the measurement. As this test requires a dynamic recovery of the seal and is thus more demanding, the tested EPDM O-ring failed earlier compared to the purely static test. The corresponding ageing state was defined as the point of failure and correlated to data from other test methods, corresponding e.g. to a compression set of 80 %. Based on this criterion, the lifetimes could be determined using the time-temperature superposition approach. During this work, a number of findings regarding the best way to conduct accelerated ageing experiments and lifetime predictions of O-rings, and how to avoid possible error sources, were collected and are discussed in detail. KW - Elastomer KW - Gummi KW - Degradation KW - Leckage KW - Verpressung KW - Rubber KW - Aging KW - Lifetime prediction KW - Leakage PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-397374 DO - https://doi.org/10.14279/depositonce-5827 SP - 1 EP - 121 PB - Technische Universität CY - Berlin AN - OPUS4-39737 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Pourmand, P. A1 - Wolff, Dietmar A1 - Hedenqvist, M. T1 - Analysis of O-ring seal failure under static conditions and determination of end-of-lifetime criterion N2 - Determining a suitable and reliable end-of-lifetime criterion for O-ring seals is an important issue for long-term seal applications. Therefore, seal failure of ethylene propylene diene rubber (EPDM) and hydrogenated nitrile butadiene rubber (HNBR) O-rings aged in the compressed state at 125 °C and at 150 °C for up to 1.5 years was analyzed and investigated under static conditions, using both non-lubricated and lubricated seals. Changes of the material properties were analyzed with dynamic-mechanical analysis and permeability experiments. Indenter modulus measurements were used to investigate DLO effects. It became clear that O-rings can remain leak-tight under static conditions even when material properties have already degraded considerably, especially when adhesion effects are encountered. As a feasible and reliable end-of-lifetime criterion for O-ring seals under static conditions should include a safety margin for slight dimensional changes, a modified leakage test involving a small and rapid partial decompression of the seal was introduced that enabled determining a more realistic but still conservative end-of-lifetime criterion for an EPDM seal. KW - EPDM KW - HNBR KW - Seal failure KW - Leak-tightness KW - DLO KW - Oxygen permability KW - DMA KW - Indenter modulus PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486125 DO - https://doi.org/10.3390/polym11081251 SN - 2073-4360 VL - 11 IS - 8 SP - 1251, 1 EP - 19 PB - MDPI CY - Basel, CH AN - OPUS4-48612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Frei, Vivian A1 - Thiele, Marc A1 - Pirskawetz, Stephan A1 - Meng, Birgit A1 - Rogge, Andreas T1 - Characterizing the Fatigue Behavior of High-Performance Concrete for Wind Energy Structures N2 - Severe mechanical fatigue conditions for worldwide proliferating windfarms are a Major challenge for high-performance concrete in towers, connecting joints and foundations of wind turbines. High-performance concrete offers potential for the application in offshore windfarms, not only regarding its good mechanical, but also chemical resistivity due to low diffusivity in the highly densified microstructure. For a more reliable fatigue assessment, monitoring based on nondestructive testing can be a valuable complement to design rules. Both approaches demand reliable experimental data, information about scalability and the development of standardized testing methods. This article presents results of an ongoing research program of BAM (Bundesanstalt für Materialforschung und -prüfung), which is a part of a joint national project (WinConFat) funded by the German Federal Ministry for Economic Affairs and Energy. The subproject implemented by BAM examines the fatigue behavior in dependence of size and slenderness for varying concrete strength at different stress levels. Besides fatigue strength, nondestructive testing is carried out additionally. Methods used are strain measurement and ultrasonic testing. The change of strain, stiffness and ultrasonic pulse velocity in the fatigue process is discussed. Results disclose a deeper insight into the damage process under cyclic loading of high-performance concrete and contribute to improve nondestructive monitoring. T2 - LORCENIS - Long Lasting Reinforced Concrete fpr Energy Infrastructure under Severe Operating Conditions CY - Ghent, Belgium DA - 10.09.2019 KW - Compressive Cyclic loading KW - Fatigue KW - High-strength concrete KW - Non destructive testing KW - Ultrasonic testing PY - 2019 SN - 978-9-463-88638-3 SP - 1 EP - 4 AN - OPUS4-49500 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas T1 - Vibrational density of states and molecular mobility in a polymer with intrinsic microporosity PIM-1 as revealed by inelastic neutron scattering N2 - Polymers with intrinsic microporosity are promising candidates for the active separation layer in gas separation membranes. Here, by means of inelastic neutron scattering, the vibrational density of states (VDOS) and the molecular mobility were investigated for PIM-1, the prototypical polymer with intrinsic microporosity. The results are compared to data measured for a more conventional high-performance polyimide used in gas separation membranes (Matrimid). The measured data show the characteristic low frequency excess contribution to the VDOS above the Debye sound wave level, generally known as the Boson peak in glass-forming materials. In comparison to the Boson peak of Matrimid, that of PIM-1 is shifted to lower frequencies. This shift is discussed considering the microporous, sponge-like structure of PIM-1 as providing a higher compressibility at the molecular scale than for conventional polymers. Elastic fixed window scans were measured on a neutron backscattering spectrometer to have an overview about the molecular dynamics at a time scale of ca. 1 ns. The temperature dependence of the estimated mean squared displacement shows a step-like increase in the temperature range from 100 K to 250 K indicating the onset of some molecular mobility. The nature of this motional process was analyzed in detail by quasielastic neutron scattering combining Time-of-Flight and backscattering where the data are discussed with regard to both the q- and the temperature dependence. T2 - JCNS Workshop for Neutron Scattering CY - Tutzing at Munich, Germany DA - 07.10.2019 KW - Polymers of Intrinsic Microporosity KW - Neutron Scattering PY - 2019 AN - OPUS4-49271 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo T1 - Applications on Surface Functionalization by Laser-Induced Periodic Surface Structures (LIPSS) N2 - In recent years, the understanding on the formation of laser-induced periodic surface structures (LIPSS) has led to an emerging variety of applications that modify the optical, mechanical and chemical properties of many materials. Such structures strongly depend on the used polarization and are formed usually after irradiation with ultrashort linearly polarized laser pulses. Some specific formation mechanisms to explain every situation are still to be uncovered, but the most accepted explanation relies on the interference of the incident laser beam with electromagnetic surface waves that propagate or scatter at the surface of the irradiated materials. This leads to an intensity modulation that is finally responsible for the selective ablation in the form of parallel structures with periodicities ranging from hundreds of nanometers up to some micrometers. The versatility when forming such structures is based on the high reproducibility with different wavelength, pulse duration and repetition rate laser sources, customized micro- and nanometric spatial resolutions and compatibility with industrially relevant processing speeds when combined with fast scanning devices. In this contribution, we review the latest applications in the rapidly emerging field of surface functionalization through LIPSS, including biomimetic functionalities on fluid transport, control of the wetting properties, specific optical responses in technical materials, improvement of tribological performance on metallic surfaces and bacterial and cell growth for medical devices among many others. T2 - 38th International Congress on Applications of Lasers and Electro Optics (ICALEO 2019) CY - Orlando, FL, USA DA - 07.10.2019 KW - Laser-induced periodic surface structures, LIPSS KW - Femtosecond laser ablation KW - Surface functionalization KW - Applications PY - 2019 AN - OPUS4-49473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Duffner, Eric A1 - Wang, Bin A1 - Kriegsmann, Andreas T1 - WP8 RCS standardisation work, Probabilistic safety assessment & statistic N2 - Achievements within WP8 in the TAHYA Project during the first 18 month, including ongoing work and next steps. Including safety definition, introduction to probabilistic Approach, failure rate, consequence and risk Definition, introduction monte-carlo-Simulation. T2 - TAHYA Midterm review meeting CY - Brüssel, Belgium DA - 26.09.2019 KW - TAHYA project PY - 2019 AN - OPUS4-49191 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Frei, Vivian T1 - Characterizing the Fatigue Behavior of High-Performance Concrete for Wind Energy Structures N2 - Severe mechanical fatigue conditions for worldwide proliferating windfarms are a Major challenge for high-performance concrete in towers, connecting joints and foundations of wind turbines. High-performance concrete offers potential for the application in offshore windfarms, not only regarding its good mechanical, but also chemical resistivity due to low diffusivity in the highly densified microstructure. For a more reliable fatigue assessment, monitoring based on nondestructive testing can be a valuable complement to design rules. Both approaches demand reliable experimental data, information about scalability and the development of standardized testing methods. This article presents results of an ongoing research program of BAM (Bundesanstalt für Materialforschung und -prüfung), which is a part of a joint national project (WinConFat) funded by the German Federal Ministry for Economic Affairs and Energy. The subproject implemented by BAM examines the fatigue behavior in dependence of size and slenderness for varying concrete strength at different stress levels. Besides fatigue strength, nondestructive testing is carried out additionally. Methods used are strain measurement and ultrasonic testing. The change of strain, stiffness and ultrasonic pulse velocity in the fatigue process is discussed. Results disclose a deeper insight into the damage process under cyclic loading of high-performance concrete and contribute to improve nondestructive monitoring. T2 - LORCENIS - Long Lasting Reinforced Concrete for Energy Infrastructue under Severe Operating Conditions CY - Gent, Belgium DA - 10.09.2019 KW - Compressive Cyclic loading KW - Fatigue KW - High-strength concrete KW - Non destructive testing KW - Ultrasonic testing PY - 2019 AN - OPUS4-49474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nerger, Deborah T1 - Improved tomographic investigation for impact damage characterization N2 - Reinforced concrete (RC) is used as structural material in most diverse civil engineering applications. For the variability of its physical properties it is still an engineering challenge to meet all necessary requirements for the prediction of dynamic effects under impact loading. In this paper, investigations are shown within the scope of quantifying and evaluating the damage caused by an impact. The experimental investigations are performed in the field of low- and medium-velocity impact. The chosen flat nose shape results in small penetrations on the top side and scabbing on the bottom side. The plate is scanned with an adapted planar tomographic examination after the impact, and the damage is analysed, afterwards. Cracks and spalling are made visible with a reconstruction. The numerical model validated on the tomographic results justifies the application for further predictions of the damage description. T2 - 25th International Conference on Structural Mechanics in Reactor Technology - SMIRT25 CY - Charlotte, NC, USA DA - 04.08.2019 KW - Impact KW - Damage characterization KW - Planar tomography KW - Numeric simulation KW - Reinforced concrete structure PY - 2019 AN - OPUS4-49540 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Linnemann, Konrad A1 - Ballheimer, Viktor A1 - Sterthaus, Jens A1 - Rolle, Annette A1 - Wille, Frank A1 - Vlassopoulos, Efstathios A1 - Papaioannou, Dimitrios T1 - Numerical Simulation of Spent Fuel Segments under Transport Loads N2 - Packages for the transport of spent nuclear fuel shall meet the International Atomic Energy Agency regulations to ensure safety under different transport conditions. The physical state of spent fuel and the fuel rod cladding as well as the geometric configuration of fuel assemblies are important inputs for the evaluation of package capabilities under these conditions. Generally, the mechanical behavior of high burn-up spent fuel assemblies under transport conditions shall be analyzed with regard to the assumptions which are used in the containment and criticality safety analysis. Considering the complexity of the interactions between the fuel rods as well as between the fuel assemblies, basket, and cask containment, the exact mechanical analysis of such phenomena is nearly impossible. The gaps in Information concerning the material properties of cladding and pellet behavior, especially for the high burn-up fuel, make the analysis more complicated additionally. As a result, enveloping analytical approaches are usually used by BAM within the safety assessment of packages approved for transport of spent nuclear fuel. To justify the safety margins of such approaches additional analyses are necessary. In this paper, numerical simulations of a spent fuel assembly Segment are presented. The segment modeled represents the part of a generalized BWR fuel assembly between two spacers. Dynamic and quasi-static finite element calculations are performed to simulate the spent fuel behavior under regulatory defined accident conditions of transport. Beam elements are used for the modeling of the fuel rods representing the compound consisting of claddings and fuel pellets. The dynamic load applied is gathered from an experimental drop test with a spent fuel cask performed at BAM. A hot cell bending test performed at JRC Karlsruhe is the basis for obtaining the material behavior of the fuel rods. The material properties are determined by simulating the test setup of JRC and optimizing the results to fit the experimental load deflection curve. The simulations of the fuel assembly segment are used to get a better understanding about the loads on fuel rods under accident conditions of transport. T2 - 17th International High-Level Radioactive Waste Management Conference (IHLRWM 2019) CY - Knoxville, Tennessee, USA DA - 14.04.2019 KW - Spent Nuclear Fuel KW - Finite Element Simulation KW - Transport packages PY - 2019 SN - 978-1-51088-669-8 SP - 1 EP - 7 AN - OPUS4-52046 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zencker, Uwe T1 - Brittle failure of spent fuel claddings during long-term dry interim storage N2 - In order to demonstrate the safety of both spent fuel and the storage system, a good understanding of the processes that might cause deterioration is required. The International Atomic Energy Agency (IAEA) continued the coordinated research on Spent Fuel Performance Assessment and Research (SPAR) into a fourth phase starting in 2015 to evaluate fuel and materials performance under wet and dry storage and to assess the impact of interim storage on associated spent fuel management activities (such as handling and transport). BAM’s understanding and experiences in the field of long-term storage of spent fuel and especially spent fuel characterization are presented to assist the preparation of the final project report. T2 - IAEA CRP SPAR-IV Third Research Coordination Meeting (RCM3) CY - Buenos Aires, Argentina DA - 07.10.2019 KW - Fuel rod KW - Cladding KW - Radial hydrides KW - Ring compression test KW - Failure analysis PY - 2019 AN - OPUS4-56006 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zencker, Uwe T1 - Embrittlement of spent fuel claddings during long-term dry interim storage - Current approach at BAM N2 - The integrity of fuel rods and cladding tubes must be demonstrated throughout the dry interim storage of spent nuclear fuel in Germany. For at least a relevant number of casks, an extension of interim storage between 40 and 100 years is foreseeable. The drying procedure for the fuel rods in conjunction with the thermomechanical storage conditions may change the microstructure of the cladding tubes and lead to their possible embrittlement. The failure probability might increase under mechanical load by handling procedures (transport after storage) on potentially embrittled cladding tubes of fuel rods especially at low temperatures after long-term storage. Results of ring compression tests on unirradiated pre-hydrided as well as irradiated samples with radial hydrides are investigated by finite element analyses to be able to describe the failure process and to identify failure criteria. T2 - EPRI Extended Storage Collaboration Program (ESCP) Winter 2019 Meeting CY - Charlotte, NC, USA DA - 04.11.2019 KW - Fuel rod KW - Cladding KW - Radial hydrides KW - Ring compression test KW - Failure analysis PY - 2019 AN - OPUS4-56005 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zencker, Uwe T1 - Spent Fuel Characterization - Current Activities in Germany N2 - The characterization of spent fuel and radioactive waste is essential in the evaluation of the ability of these materials to meet acceptance criteria. Prior to determining a method for spent fuel characterization, it is necessary to identify the type of data required to support safety and other analyses for the storage, transportation and final disposal of spent fuel. BAM’s understanding and capabilities in the field of spent fuel characterization are presented for the scope of a coordinated research project on the topic. T2 - IAEA Technical Meeting on Spent Fuel Characterization for Management of Spent Fuel in the Back End of the Fuel Cycle CY - Vienna, Austria DA - 12.11.2019 KW - Nuclear fuel cycle KW - Back end KW - Spent fuel characterization KW - Storage KW - Transportation PY - 2019 AN - OPUS4-55866 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gröke, Carsten A1 - Neumann, Martin A1 - Komann, Steffen A1 - Wille, Frank T1 - Anforderungen an die Bauartprüfung und Maßnahmen zur Qualitätssicherung für nicht zulassungspflichtige Versandstücke N2 - Überblick über die Regelwerksanforderungen an die Bauarten von nicht zulassungspflichtigen Versandstücken, sowie die zu erfüllenden Maßnahmen zur Qualitätssicherung für die Auslegung, die Herstellung und den Betrieb. T2 - KONTEC 2019 CY - Dresden, Germany DA - 27.03.2019 KW - Radioaktiv KW - Beförderung KW - IP-2 KW - IP-3 KW - Typ A KW - Anerkennung KW - Bauartprüfung PY - 2019 SP - 136 EP - 142 AN - OPUS4-56343 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Linnemann, Konrad T1 - Numerical simulation of spent fuel segments under transport loads N2 - Packages for the transport of spent nuclear fuel shall meet the International Atomic Energy Agency regulations to ensure safety under different Transport conditions. The physical state of spent fuel and the fuel rod cladding as well as the geometric configuration of fuel assemblies are important inputs for the evaluation of package capabilities under these conditions. Generally, the mechanical behavior of high burn-up spent fuel assemblies under Transport conditions shall be analyzed with regard to the assumptions which are used in the containment and criticality safety analysis. In view of the complexity of the interactions between the fuel rods as well as between the fuel assemblies, basket, and cask containment, the exact mechanical analysis of such phenomena is nearly impossible. The gaps in information concerning the material properties of cladding and pellet behavior, especially for the high burn-up fuel, make the analysis more complicated additionally. As a result, enveloping analytical approaches are usually used by BAM within the safety assessment of packages approved for transport of spent nuclear fuel. To justify the safety margins of such approaches additional analyses are necessary. In this paper, numerical simulations of a segment of a spent fuel assembly are presented. The segment modeled represents the part of a generalized BWR fuel assembly between two spacers. Explicit dynamic finite element calculations are performed to simulate the spent fuel behavior under regulatory defined accident conditions of transport. A beam element formulation is used for the modeling of the fuel rods representing the compound consisting of claddings and fuel pellets. The load applied is gathered from experimental drop tests with spent fuel casks performed at BAM. A hot cell bending test performed at JRC Karlsruhe is the basis for obtaining the material behavior of the fuel rods. The material properties are determined by simulating the test setup of JRC and optimizing the results to fit the experimental load deflection curve. The simulations of the fuel Assembly segment are used to get a better understanding about the loads on fuel rods under accident conditions of transport. T2 - 17th International High-Level Radioactive Waste Management Conference (IHLRWM 2019) CY - Knoxville, Tennessee, USA DA - 14.04.2019 KW - Spent Nuclear Fuel KW - Finite Element Simulation KW - Transport packages PY - 2019 AN - OPUS4-52047 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. T1 - Relevante Entwicklungen zu Speichern für Gase als Energieträger N2 - Es werden die Zusammenhänge des Druckvolumenprodukts und der Konsequenz bei Druckgasen insbesondere für Wasserstoff dargestellt. Entsprechend werden Stellungnahmen zu verschiedenen Normungsprojekten abgeleitet und perspektivische Entwicklungen mit dem resultierenden Bedarf in der Normung dargestellt. Außerdem wird am Beispiel ein Problem in der praktischen Beurteilung von Speicherpopulationen für Batteriefahrzeuge diskutiert. T2 - 26. BAM-DIN-IGV-DVFG-Gespräch 2019 CY - Berlin, Germany DA - 27.02.2019 KW - Wasserstoffspeicher KW - Konsequenzbegrenzung KW - Normung KW - Druck-Volumen-Produkt KW - Katastrophe KW - Akzeptanz PY - 2019 AN - OPUS4-53145 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gröke, Carsten T1 - Requirements for Package Design Testing and Quality Assurance Measures for Packages not Requiring Competent Authority Design Approval N2 - Übersicht über die gefahrgutrechtlichen Anforderungen zur Bauartprüfung und dem Qualitätsmanagement für Verpackungen für nicht zulassungspflichtige Versandstücke. T2 - KONTEC 2019 CY - Dresden, Germany DA - 27.03.2019 KW - Bauartprüfung KW - Qualitätsmanagement KW - Nicht zulassungspflichtig PY - 2019 AN - OPUS4-56352 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg T1 - Redox properties of Cu ions in molecular sieves N2 - Molecular sieves as materials with defined pores offer new opportunities in the preparation of nanostructured materials for different applications in chemistry, medicine and biology. Typical examples for such materials are zeolites, porous glass, different silicas and active carbon. Introducing transition metal ions in such materials can widen the possibilities of these materials in terms of chemical activity. Especially, the opportunity to tailor the redox properties of the transition metal ions by varying the location of the ion in the sieves is a promising way to obtain catalysts with the desired properties. For this purpose, Cu2+ ions were introduced into a SAPO-5 (silicoaluminaphosphate) by a hydrothermal method and by impregnation. As expected, the different preparation methods led to different locations of the Cu2+ ions: by the hydrothermal method the ions were incorporated in the SAPO-5 framework, by impregnation mononuclear Cu species randomly distributed in the pores of the support or CuO particles were formed depending on the Cu amount. These locations could be determined by Extended X-ray Absorption Fine Structure and Anomalous Small-Angle X-ray Scattering investigations. For investigating the redox properties of the Cu2+ ions the differently prepared sample were treated in Ar and H2 atmosphere until 550°C. X-ray Photoelectron Spectroscopy was performed to study the valence states of Cu after each of such treatment. For a definite determination of the valence states, both Cu 2p and Cu LMM spectra must be recorded. Cu2+ exhibits a clear chemical shift and a typical satellite structure in Cu2p spectra, but between mono- and zerovalent Cu a differentiation is not possible. On the other hand, these two species show a clear shift in the Auger spectra. Whereas in H2 atmosphere in any case metallic Cu was formed, the treatment in Ar showed significant differences between the samples. Cu2+ incorporated in the framework could not be reduced by this treatment. In contrast, the mononuclear Cu2+ species were reduced to stable Cu+. Likewise, the CuO nanoparticles were reduced to the monovalent Cu, but this species can be much more easily reoxidized in air. The consequences for the catalytic properties will be discussed. T2 - ECASIA 2017 CY - Montpellier, France DA - 24.09.2017 KW - Catalysis KW - X-ray photoelectron spectroscopy KW - Nanostructured materials PY - 2017 AN - OPUS4-42323 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Jan P. T1 - Applying a two-layer quadrupole model for quantitative thermography at overload-induced delaminations in GFRP N2 - The applicability of 1D-quadrupole-model on the depth estimation of overload-induced delaminations is tested in this contribution. While classical 1D-methods like Pulsed Phase Transformation and Thermographic Signal Reconstruction determine the depth of a defect by one parameter, a two-layer quadrupole model provides two parameters: depth and thermal resistance. In addition, the convectional losses at the surfaces may be considered. The defect investigated is a large-scale delamination in glass fibre reinforced polymer generated by tension overload. T2 - Advanced Infrared Technology & Applications (AITA) CY - Florenz, Italy DA - 16.9.2019 KW - Aktive Thermographie KW - Nicht-lineare Regression KW - 1D-Simulation KW - GFK PY - 2019 AN - OPUS4-49133 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Herrmann, Ralf T1 - Introduction and Current Research in Wind Energy N2 - The EERA Wind is a Joint Program for coordination of research in wind energy. In the subprogram SP7 "Structures, materials and components" BAM introduces its current research topics in the field of on- and offshore wind energy and structural health monitoring. T2 - EERA Joint Program Wind: SP7 WORKSHOP on Structures, Materials and Components CY - Amsterdam, Niederlande DA - 24.09.2019 KW - Offshore KW - Wind energy KW - EERA Joint Program PY - 2019 AN - OPUS4-49203 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Palkowski, Carsten T1 - Dynamic Test Method for Heat Pumps and Air Conditioners N2 - Die bisher üblichen Verfahren zur Bewertung der Effizienz einer Wärmepumpe durch Labormessungen berücksichtigen kaum transiente Zustände. Können dynamische Bewertungsverfahren im Labor ein realistischeres Verhalten im Feld wiederspiegeln und damit zu sinnvolleren Entscheidungen führen? N2 - The commonly used methods for evaluating the seasonal performance of heat pumps in the laboratory do not consider transient conditions. Will dynamic test methods be able to better reflect real-life behavior in the field and thus lead to more appropriate decision-making? T2 - EHPA MCO CY - Brussels, Belgium DA - 10.10.2019 KW - Heat pump KW - Inverter-type air conditioner KW - Seasonal performance KW - Energy label PY - 2019 AN - OPUS4-49270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baeßler, Matthias T1 - Stability and large deformations of slender structures supported by soil materials N2 - Stabilitätsprobleme und große Deformationen schlanker, vorwiegend stahlbaulicher Strukturen sind in einigen Fällen stark von der Belastung und Stützung der Struktur durch den Baugrund abhängig. Der Vortrag verbindet Forschungsansätze zum Thema. T2 - Colloquium on Geotechnical Engineering CY - KIT Karlsruhe, Germany DA - 26.09.2019 KW - Stability Buckling soil-structure-interaction piles offshore PY - 2019 AN - OPUS4-49162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Duffner, Eric A1 - Szczepaniak, Mariusz A1 - Schoppa, Andre T1 - Abteilung 3 und Arbeitsbereich „Themenfeld Energie Gase" N2 - Vorstellung der Aufgaben-/Forschungs- und Prüfungsschwerpunkte des Arbeitsbereichs "Themenfeld Energie Gase" T2 - Besuch Expertengruppe der BG RCI CY - BAM Berlin, Germany DA - 15.05.2019 KW - Arbeitsbereichs "Themenfeld Energie Gase" PY - 2019 AN - OPUS4-49199 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Jan P. T1 - Ein Blick unter die Oberfläche von Windkraftanlagen durch Thermografie N2 - Rotorblätter von Windkraftanlagen sind hohen Belastungen ausgesetzt. Nach Jahren der Nutzung können Klebeverbindungen unter der Oberfläche versagen. Thermografie soll die Zustandsüberwachung während der gesamten Lebensdauer verbessern. N2 - Rotor blades of wind power generators are subject to high strains. After years of use, adhesive bonds under the surface may fail. Thermography is intended to improve condition monitoring during the entire service life. T2 - Hannover Messe 2019 CY - Hanover, Germany DA - 1.4.2019 KW - Wiederkehrende Prüfung KW - Thermografie KW - Klebeverbindungen KW - Rotorblatt KW - GFK PY - 2019 AN - OPUS4-49160 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Duffner, Eric A1 - Kriegsmann, Andreas T1 - WP8 - RCS standardisation work N2 - Achievements and next steps within WP8 "RCS standardisation work" in the TAHYA Project. T2 - TAHYA Meeting PSB#2 CY - Saarburg, Germany DA - 11.06.2019 KW - TAHYA project PY - 2019 AN - OPUS4-49190 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Duffner, Eric A1 - Szczepaniak, Mariusz T1 - Pressure cylinders for the transport of dangerous goods N2 - Introduction of the Department 3 and the competence and scientific focus of the working group focus area energy - gases for external visitors. T2 - Besuch einer Studentengruppe der AGH Krakau CY - BAM Berlin, Germany DA - 23.09.2019 KW - Introduction Department 3 KW - Focus area energy gases PY - 2019 AN - OPUS4-49193 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Duffner, Eric T1 - System validation and safety aspects N2 - Overview of the achievements, issues and next steps with in TAHYA Project for WP5 T2 - TAHYA meeting PSB#2 CY - Saarburg, Germany DA - 11.06.2019 KW - TAHYA Project PY - 2019 AN - OPUS4-49188 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Duffner, Eric A1 - Kriegsmann, Andreas A1 - Szczepaniak, Mariusz T1 - WP5 - System validation phase and safety aspects N2 - Objectives, tasks, achievements, ongoing work and next steps within WP5 in the TAHYA Project during the first 18 month T2 - TAHYA Midterm review meeting CY - Brüssel, Belgium DA - 26.10.2019 KW - TAHYA project PY - 2019 AN - OPUS4-49192 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. A1 - Saul, Herbert A1 - Wang, Bin T1 - Safety criteria for the transport of hydrogen in permanently mounted composite pressure vessels N2 - The recent growing of the net of hydrogen fuelling stations increases the demands to transport compressed hydrogen on road by batterie vehicles or tube-trailers, both in composite pressure vessels. As transport regulation the ADR is applicable in Europe and adjoined regions and used for national transport in EU. This regulation provides requirements based on the burst pressure of each individual pressure vessel, regardless the capabilities of the transported hydrogen and relevant consequences resulting from worst case scenarios. In 2012, BAM (German Federal Institute for Materials Research and Testing) introduced consequence-dependent requirements and established them in national requirements concerning the “UN service life checks” etc. to consider the transported volume and pressure of gases. However, this results in a stringent requirement in case of using large pressure vessels (so called “tubes”) on vehicles. In the studies presented here, the safety measures for hydrogen road transport are identified and reviewed through some safety measures from some countries like Japan, USA and China. Subsequently, the failure consequences of using trailers, the related risks and chances are evaluated. Finally, a chance-related risk criterion is suggested to add into regulations and consequently to be defined as safety goal in standards for hydrogen transport vehicles and consequently for mounted pressure vessels. T2 - ICHS International Conference on Hydrogen Safety) 2019 CY - Adelaide, Australia DA - 24.09.2019 KW - pressure-volume product KW - probabilistic approach KW - hydrogen transport KW - risk limit KW - F-N-diagram KW - maximum acceptable consequence KW - chance-risk analysis KW - specific risk value PY - 2019 SP - 104-01 EP - 104-15 PB - International Association for Hydrogen Safety (HySafe) CY - Adelaide AN - OPUS4-50124 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wang, Bin A1 - Mair, Georg W. A1 - Gesell, Stephan T1 - Determination of Distribution Function used in MCS on Safety Analysis of Hydrogen Pressure Vessel N2 - The test data of static burst strength and load cycle strength of composite pressure vessels are often described by GAUSSian normal or WEIBULL distribution function to perform safety analyses. The goodness of assumed distribution function plays a significant role in the inferential statistics to predict the population properties by using limited test data. Often, GAUSSian and WEIBULL probability nets are empirical methods used to validate the distribution function; Anderson-Darling and Kolmogorov-Smirnov tests are the mostly favorable approaches for Goodness of Fit. However, the different approaches used to determine the parameters of distribution function lead mostly to different conclusions for safety assessments. In this study, six different methods are investigated to show the variations on the rates for accepting the composite pressure vessels according to GTR No. 13 life test procedure. The six methods are: a) Norm-Log based method, b) Least squares regression, c) Weighted least squares regression, d) A linear approach based on good linear unbiased estimators, e) Maximum likelihood estimation and f) The method of moments estimation. In addition, various approaches of ranking function are considered. In the study, Monte Carlo simulations are conducted to generate basic populations based on the distribution functions which are determined using different methods. Then the samples are extracted randomly from a population and evaluated to obtain acceptance rate. Here, the “populations” and “samples” are corresponding to the burst strength or load cycle strength of the pressure vessels made from composite material and a plastic liner (type 4) for the storage of hydrogen. To the end, the results are discussed, and the best reliable methods are proposed. T2 - ICHS International Conference on Hydrogen Safety) 2019 CY - Adelaide, Australia DA - 24.09.2019 KW - Monte-Carlo Simulation KW - Distribution function KW - Weibull Distribution PY - 2019 SP - 103-1 EP - 103-16 AN - OPUS4-50383 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. A1 - Gesell, Stephan T1 - Betriebsfestigkeit von Composite-Wasserstoffspeichern Erster Ansatz zur Simulation der Auswirkung der erstmaligen Prüfung N2 - Druckbehälter werden vor ihrer Inbetriebnahme obligatorisch einer hydraulischen Prüfung bis zum sog. Prüfdruck belastet. Damit sollen fehlerhaft gefertigte Individuen erkannt und ausgesondert werden. Mit dieser Prüfung werden aber auch diejenigen Einzelbehälter ausgesondert, die ohne einem nachvollziehbaren Fertigungsfehler, nur auf Basis der statistischen Streuung ggf. eine Festigkeit unterhalb des Prüfdrucks aufweisen. Da der Prüfdruck im Fall der Wasserstoffspeicher mindestens 20% über dem maximal zulässigem Betriebsdruck liegt, wäre damit ein Versagen im Betrieb ausgenommen, gäbe es die verschiedenen Alterungs- bzw. Ermüdungseffekt nicht. Um den Einfluss der erstmaligen Prüfung auf eine angenommene ausfallfreie Zeit bewerten zu können, wird hier die Alterung und die erstmalige Prüfung in Kombination analysiert. Hierzu wird auf Basis der Restfestigkeitsdaten aus einer umfangreichen Prüfkampagne ein Ansatz für die Beschreibung der Alterung ermittelt und auf andere Lastzustände übertragen. So kann für das Baumuster, das der o.g. Prüfkampagne zugrunde lag, mithilfe einer Monte-Carlo-Simulation gezeigt werden, dass mindestens 10.000 LW vor einem ersten Alterungsversagen mit 1 aus 1 Mio. In Abhängigkeit der Anzahl der Individuen, die bei der erstmaligen Prüfung versagen, und der Streuung der gesamten Population, kann diese Mindestfestigkeit auf realistisch 50.000 Lastwechsel steigen. Damit ist gezeigt, dass aufgrund der erstmaligen Prüfung eine Mindestfestigkeit erzeugt wird, die stark vom Alterungsverhalten abhängt. Im Ergebnis heißt dies, dass in den Vorschriften aktuell die Bedeutung des Mindestberstdrucks in der Baumusterprüfung überschätzt und die möglichst betriebsbegleitende Erfassung der Alterung unterschätzt sind. T2 - 29. Fachtagung Technische Zuverlässigkeit 2019 CY - Nürtingen, Germany DA - 07.05.2019 KW - Alterung KW - Berstdruck KW - Streuung KW - Degradation KW - statistische Auswertung KW - ausfgallfreie Lastwechsel PY - 2019 SN - 978-3-18-092345-1 SN - 0083-5560 SP - 223 EP - 234 PB - VDI-Verlag GmbH CY - Düsseldorf AN - OPUS4-50181 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Quercetti, Thomas A1 - Scheidemann, Robert A1 - Komann, Steffen A1 - Ballheimer, Viktor A1 - Wille, Frank T1 - Package testing of a dual purpose cask for SNF from German research reactors N2 - A new dual purpose cask design was developed for the safe transport and interim storage of spent fuel elements of German research reactors. In the framework of the safety assessment within the licensing procedure the Bundesanstalt für Materialforschung und –prüfung (BAM) as competent authority performed a series of drop tests according to the IAEA-Regulations [1]. The package consists of a cylindrical thick-walled ductile cast iron cask body closed by a double lid system with metallic seals. A lid and bottom sided impact limiter consisting of a wood/steel construction limit the mechanical impact loading. The full-scale test specimen was equipped with a basket and assembled with dummy-fuel elements. The package and test specimen, respectively have a total mass of approximately 24 metric tons. The mechanical test program included three 9m free drop tests, in horizontal, vertical and oblique cask orientation onto the lid system. Additionally, a 1m-puncture drop test followed the horizontal drop test to consider an IAEA-test sequence. The horizontal and vertical drop tests were performed at a temperature of minus 40°C. During the oblique drop test the upper impact limiter was heated to +80°C. The tests were conducted onto an unyielding target, fulfilling the requirements of the IAEA regulations [1]. The test specimen was considerably instrumented with strain gauges and accelerometers. Transient strains at selected locations of the inner and outer container walls, of the primary and secondary lid, as well as of the corresponding lid bolts were measured during the drop tests. Furthermore, decelerations in different locations at the cask body and the lids were measured. The complex geometrical deformation of the impact limiters due to the impact were determined by optical 3d- measurements using the projected fringe method in combination with multi-image photogrammetry. Before and after the drop tests the leakage rate of the lid system was determined by helium leakage testing. The experimental results contribute to the evaluation of the package response to mechanical tests, demonstrating safety under normal and accident conditions of transport. Especially to the verification of the dynamic finiteelement model of the package used in the package design safety report [2]. The paper describes the performance of the drop tests, selected test results focusing on the lid screws and the cask body and the deformation of the impact limiters as well as impact kinematics, respectively. T2 - IHLRWM2019 CY - Knoxville, TN, USA DA - 14.04.2019 KW - Drop test KW - Package testing KW - Dual purpose cask PY - 2019 SN - 978-0-89448-761-3 VL - 2019 SP - paper 27283, 1 EP - 7 PB - ANS AN - OPUS4-50619 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Quercetti, Thomas T1 - Package testing of a dual purpose cask for SNF from german research reactors N2 - A new dual purpose cask design was developed for the safe transport and interim storage of spent fuel elements of German research reactors. In the framework of the safety assessment within the licensing procedure the Bundesanstalt für Materialforschung und –prüfung (BAM) as competent authority performed a series of drop tests according to the IAEA-Regulations. The package consists of a cylindrical thick-walled ductile cast iron cask body closed by a double lid system with metallic seals. A lid and bottom sided impact limiter consisting of a wood/steel construction limit the mechanical impact loading. The full-scale test specimen was equipped with a basket and assembled with dummy-fuel elements. The package and test specimen, respectively have a total mass of approximately 24 metric tons. The mechanical test program included three 9m free drop tests, in horizontal, vertical and oblique cask orientation onto the lid system. Additionally, a 1m-puncture drop test followed the horizontal drop test to consider an IAEA-test sequence. The horizontal and vertical drop tests were performed at a temperature of minus 40°C. During the oblique drop test the upper impact limiter was heated to +80°C. The tests were conducted onto an unyielding target, fulfilling the requirements of the IAEA regulations. The test specimen was considerably instrumented with strain gauges and accelerometers. Transient strains at selected locations of the inner and outer container walls, of the primary and secondary lid, as well as of the corresponding lid bolts were measured during the drop tests. Furthermore, decelerations in different locations at the cask body and the lids were measured. The complex geometrical deformation of the impact limiters due to the impact were determined by optical 3d- measurements using the projected fringe method in combination with multi-image photogrammetry. Before and after the drop tests the leakage rate of the lid system was determined by helium leakage testing. The experimental results contribute to the evaluation of the package response to mechanical tests, demonstrating safety under normal and accident conditions of transport. Especially to the verification of the dynamic finiteelement model of the package used in the package design safety report. The paper describes the performance of the drop tests, selected test results focusing on the lid screws and the cask body and the deformation of the impact limiters as well as impact kinematics, respectively. T2 - Workshop ORNL/BAM CY - Oak Ridge National Laboratory, TN, USA DA - 11.04.2019 KW - Package testing KW - Drop test PY - 2019 AN - OPUS4-50621 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thomas, Sebastian T1 - WP8 RCS standardisation work, probabilistic safety assessment & statistic - PSB meeting #3 N2 - Achievements within WP8 in the TAHYA Project during the month 18 to 24, including ongoing work and next steps. Including safety definition, introduction to probabilistic Approach, failure rate, consequence and risk Definition, introduction monte-carlo-Simulation. T2 - TAHYA PSB meeting 3 CY - Berlin, Germany DA - 28.11.2019 KW - TAHYA project PY - 2019 AN - OPUS4-50118 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Schumacher, David T1 - Zerstörungsfreie Prüfung mit photonenzählenden und spektralauflösenden Röntgenmatrixdetektoren am Beispiel von Werkstoffverbunden N2 - Diese Arbeit beschäftigt sich mit den Eigenschaften der photonenzählenden und spektralauflösenden Detektortechnik und möglichen Anwendungsgebieten in der zerstörungsfreien Prüfung. Dabei wurden konventionelle und photonenzählende Detektortechniken hinsichtlich der Bildqualität und Anwendbarkeit bei unterschiedlichen Prüfaufgaben verglichen und untersucht, inwiefern sich die Energieschwellwertsetzung auf die erreichbare Bildqualität und eine Materialdiskriminierbarkeit bei verschiedenen radiographischen Verfahren auswirkt. Anhand von Anwendungsbeispielen wurden diese Eigenschaften und deren Auswirkung auf das Messergebnis analysiert. Neben der Radiographie wurden auch dreidimensionale Verfahren wie CT und Laminographie berücksichtigt. Als eine der wichtigsten Eigenschaften der photonenzählenden Detektortechnik wurden zunächst die Energieauflösung des photonenzählenden Detektors und die Homogenität der Energieantwort über größere Detektorbereiche bestimmt. Dabei stellte sich heraus, dass die Energieauflösung eines abgegrenzten Detektorbereichs ca. 32 % bei 60 keV beträgt und die Streuung in der Energieantwort der einzelnen Detektorbereiche ca. 12 % ausmacht, woraus sich eine Gesamtunsicherheit in der spektralen Detektorantwort von ca. 44 % ergibt. Die geringe Energieauflösung und das stark heterogene Verhalten der Detektorbereiche ergeben sich vor allem aus der Detektorelektronik, welche nur eine globale Energieschwellwertsetzung zulässt. Trotz dieser Einschränkungen konnte demonstriert werden, dass auch konventionelle radiographische Verfahren, wie Radiographie oder CT, vom Einsatz der photonenzählenden Technik profitieren. So ist es mit dieser Technik möglich, bei sehr geringen Dosisleistungen (z.B. aufgrund der Durchstrahlung großer Wandstärken von dichten Materialien) noch sehr gute Bildqualitäten zu erreichen. Die hohe Dynamik und Kontrastempfindlichkeit dieser Technik begünstigen die Inspektion von Leichtbauwerkstoffen wie Faserverbunde, was anhand von Vergleichen mit herkömmlicher Detektortechnik und anderen ZfP-Verfahren gezeigt werden konnte. Daneben konnte durch den Einsatz der Energieschwellwertsetzung der Einfluss von nicht bildzeichnender Streustrahlung im Röntgenbild um bis zu 20 % reduziert werden. Die Auswirkungen von Aufhärtungseffekten in der CT konnten sogar um bis zu Faktor 1 000 (in der mittleren quadratischen Abweichung), im Vergleich zu herkömmlicher Detektortechnik, reduziert werden. Der Einsatz von photonenzählender Detektortechnik mit Röntgenblitzröhren ist hingegen nicht sinnvoll, da aufgrund der hohen Photonendichte pro Puls und einer endlichen Totzeit des Detektors in der Größenordnung der Pulsbreite eines Blitzes nur ein geringes Signal detektiert werden kann. Im Hinblick auf eine Materialdiskriminierbarkeit konnte demonstriert werden, dass im Fall einer Radiographie anhand der Energieschwellwertsetzung im Detektor eine materialstärkenunabhängige Diskriminierung zwischen zwei Materialien (hier: Al und Fe) erzielt werden kann. Unter Einsatz mehrerer Energiefenster und eines Verfahrens der explorativen und multivariaten Datenanalyse konnte eine materialaufgelöste CT eines Multi-Material-Phantoms erreicht werden, wobei die Schwächungskoeffizienten der enthaltenen Materialien im relevanten Energieberiech teilweise sehr dicht beieinander lagen. Neben Radiographie und CT wurde auch die Möglichkeit einer materialaufgelösten Laminographie am Beispiel eines glasfaserverstärkten Rotorblatts untersucht. Anhand der Energieschwellwertsetzung war nicht nur eine eindeutige Trennung der Glasfasern von der Epoxidharzmatrix möglich, sondern auch eine signifikante Reduzierung der durch die Laminographie entstandenen Artefakte. Der damit verbundene Gewinn an Information führt zu einer verbesserten Aussagefähigkeit des Untersuchungsergebnisses, was letztendlich eine gesteigerte Betriebssicherheit zur Folge hat. N2 - This thesis investigates the properties of photon counting and energy discriminating digital detector arrays and possible applications in the field of non-destructive testing. Conventional integrating detector technology was compared with photon counting technology in terms of image quality and applicability in different inspection tasks. The impact of internal energy thresholding on material discriminability and achievable image quality was investigated for different radiological methods. The properties of photon counting detectors and their impact on the measurement result were analyzed for different applications including three-dimensional methods such as CT and laminography in addition to radiographic testing. Energy resolution is one of the most important properties of photon counting technology. Therefore, energy resolution was initially determined in addition to the homogeneity of the energy Response across the detector. It was found that the energy resolution amounts to approx. 32 % for a 60 keV monoenergetic spectrum (241Am). In combination with the variance in the response of single detector tiles of approx. 12 % the total uncertainty in the detector energy response appears to approx. 44 %. This low energy resolution and strongly heterogenous detector response result mainly from the detector electronics which only allow setting global energy thresholds. Despite these limitations it was demonstrated that even conventional single energy techniques, such as radiography or CT, benefit from photon counting technology. Thus, this technology allows to gain high quality images even at very low dose rates which might occur e.g. at high wall thickness Penetration of dense materials. The high dynamic range and high contrast sensitivity facilitate the inspection of lightweight materials such as fiber composites which was shown by comparison with integrating technology and other NDT methods. Furthermore, the use of energy thresholding enables to reduce the influence of non-imaging scattered radiation within the X-ray image by about 20 %. The impact of beam hardening artefacts in CT was reduced even up to a factor of 1 000, compared to conventional integrating detector technology. In contrast, the use of photon counting technology with x-ray flash tubes is not useful, since the high photon density within a single flash and a finite dead time of the detector only yield a very low signal. In terms of material discriminability, it was shown that due to energy thresholding a thickness Independent material separation between two materials (here: Al and Fe) can be achieved in the case of a radiography. By using more than two energy windows in combination with multivariate methods of data analysis, a material resolved CT of a multi-material phantom was performed in which six materials were separated distinctly despite very close attenuation coefficients in the relevant energy range. In addition to radiography and CT, the possibility of a material resolved laminography was investigated by means of a glass fiber reinforced wind turbine blade. In addition to a distinct separation between glass fibers and resin matrix, a significant reduction of cross artefacts that inherently arise from the laminography could be achieved. This gain in information yields a higher significance of the measurement and hence an increased reliability of the component or the whole system. T3 - BAM Dissertationsreihe - 165 KW - Zerstörungsfreie Prüfung KW - Photonenzählende Detektoren KW - Radiographie KW - Laminographie KW - Computer-Tomographie KW - Dual-Energy KW - Nondestructive testing KW - Photon counting detectors KW - Radiography KW - Laminography KW - Computed tomography KW - Dual energy PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500327 SN - 1613-4249 VL - 165 SP - 1 EP - 172 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-50032 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rica, S. A1 - Van Baars, S. A1 - Kullolli, Borana ED - Ülgen, D. ED - Saygili, A. ED - Kahyaoglu, M. R. ED - Durmaz, S. ED - Toygar, O. ED - Göcügenci, A. T1 - The importance of the horizontal stresses on the bearing capacity of a foundation pile N2 - In case one wants to predict or design the bearing capacity of a foundation pile and there are no possibilities to perform an in-situ test, such as a Cone Penetration Test, the pile bearing capacity is in most cases estimated with analytical formulas. The most known and used method is the Meyerhof method published some decades ago. There are also other design methods such as derived from a certain failure mechanism around the pile tip, which is, in most cases, wedge failure mechanism. This failure mechanism was originally developed for a shallow (infinite) strip foundation, though. Therefore, it represents a plane failure mechanism. Numerical simulations on loaded foundation piles performed with the Plaxis software Show however, that the failure mechanism of a foundation pile represents a far more complex threedimensional failure mechanism around the pile tip. In addition, the existing analytical methods for foundation piles are based on the vertical stresses in the soil, as if the failure mechanism is the same as of a shallow foundation. Numerical simulations, performed in Plaxis show that, not the vertical, but the horizontal stresses, play an important role on the pile bearing capacity. Plaxis represents the stresses in the soil by using the procedure. So, different horizontal soil stresses are obtained for different values of the lateral earth pressure coefficient. The results show that the pile tip bearing capacity depends strongly on the horizontal stresses in the soil, but only for. The same results were observed by using a Material Point Method (MPM). Consequently, the analytical methods should estimate the pile bearing. T2 - 1st Mediterranean Young Geotechnical Engineers Conference CY - Bodrum, Turkey DA - 23.09.2019 KW - Analytical Design Methods KW - Foundation Pile KW - Horizontal stress PY - 2019 UR - http://mygec2019.org/ VL - 2019 SP - 151 EP - 158 PB - 1st Mediterranean Young Geotechnical Engineers Conference CY - Bodrum, Turkey AN - OPUS4-49639 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mair, Georg W. A1 - Spode, Manfred A1 - Wang, Bin T1 - Monte Carlo simulation and evaluation of burst strength of pressure vessels N2 - The simulation of strength experiments by the Monte-Carlo method enables the numerical generation of data representing a complete populations of composite pressure vessels. In the case of composite pressure vessels used for hydrogen storage, properties like burst strength or fatigue cycle strength are of interest. This paper provides comprehensive information on how populations are generated and how samples can be taken and evaluated; it also explains how to determine the acceptance rate of random samples from simulated populations for passing the approval test "minimum burst pressure". A word of caution is also expressed regarding the evaluation of acceptance rates from a small sample. KW - Monte-Carlo simulation KW - Polar method KW - Composite cylinder KW - Burst strength KW - Acceptance rate PY - 2019 SN - 0025-5300 VL - 61 IS - 12 SP - 1152 EP - 1156 PB - Carl Hanser Verlag CY - München AN - OPUS4-49870 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tschirschwitz, Rico T1 - Forschungsergebnisse zum Verhalten von Lithiumbatterien und Erkenntnisse für die Regelwerksentwicklung N2 - Die Sicherheit von Lithiumbatterien ist ein entscheidender Punkt beim Ausbau der Elektromobilität. Der Beitrag stellt zunächst sehr allgemein die Grundlagen von Lithiumbatterien als Energiespeicher dar sowie die Gefahren, welche von diesen ausgehen können. Weiterhin wird der Beitrag der BAM zur Sicherheit von Lithiumbatterien, sowohl im experimentellen Bereich als auch bei der Regelwerksentwicklung, vorgestellt. T2 - 17. Gefahrgut-Technik-Tage CY - Berlin, Germany DA - 07.11.2019 KW - Lithiumbatterien KW - Thermisches Durchgehen KW - Gasanalytik KW - BAM TTS PY - 2019 AN - OPUS4-49727 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abad Andrade, Carlos Enrique T1 - Simultaneous multielemental analysis of crude oils by high-resolutions absorption spectrometry N2 - When crude oil arrives at a refinery it needs a lot of processing before it is suitable for cracking into lighter fractions. Sulfur has to be extracted to meet ultra-low sulfur legislation for most of the fuel grades, and desalination is a crucial process as chlorine within salts is corrosive to refinery equipment. Measuring the amounts of sulfur and chlorine within crude oil is the first step in a complex clean-up process. Heavy metals, such as vanadium, nickel and iron need to be removed too. These metals can poison the catalyst used to crack the oil into lighter fractions. This is costly as it reduces the useful life of the catalyst. Like chlorine, heavy metals also have a corrosive effect on the plant. There is some evidence that the presence of some metals in the final product can reduce performance. A fast determination of elements and size of suspended particles is vital for diagnosis and safeguard of refinery equipment. However, sample preparation for current analytical methods consumes precious time and lost particle size information. High-resolution continuum source graphite furnace absorption spectrometry (HR-CS-GFAS) is proposed as a fast analytical method for elemental determination in crude oils and potentially for simultaneous multielement and particle size analysis. This HR-CS-GFAS instrumentation is coupled to a modular simultaneous echelle spectrometer (MOSES) and provides a full optical window with high resolution (from 180 to 900 nm with bandwidth λ/170,000). By using this set-up, it is possible to generate a multiparameter 3D spectral image (atomic and molecular lines, isotopic shift, atomization delay, and intensities). The generated spectral images can be analyzed by multivariate regressions for the elemental and particle size analysis. Additionally, if several atomic and molecular lines are simultaneously measured, they may be used in multi-energy calibration (MEC), a method based on the use of many wavelengths of the same absorbing/emitting entity to improve the accuracy in analytical atomic spectrometry. This MEC approach combined with multivariate image analysis allows the quantification of selected elements (Si, Al, Ni, Fe, V, S, and Cl) and overcomes matrix effects. T2 - Chevron Seminar- Group Chemical Characterization and Atomic Spectroscopy CY - Richmond, CA, USA DA - 22.10.2019 KW - Crude oil KW - Multielemental analysis KW - HR-CS-AAS KW - Optical spectroscopy KW - MOSES PY - 2019 AN - OPUS4-49885 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Böhning, Martin T1 - The glass transition temperature of Polymers of Intrinsic Microporosity (PIMs) as determined by fast scanning calorimetry N2 - Polymers of intrinsic microporosity (PIMs) have recently emerged as novel materials for a broad range of high-performance applications from gas separation to electronic devices. The very rigid, contorted polymer chains show only limited molecular mobility and therefore pack inefficiently giving rise to intrinsic microporosity with pore sizes generally smaller than 1 nm resulting in BET surface areas larger than 700 m2/g. Using conventional thermal analysis techniques, no glass transition temperature (Tg) of PIMs could be unambiguously detected up to now. Employing fast scanning calorimetry (FSC) based on a one chip sensor, decoupling the time scales responsible for the glass transition and the thermal decomposition is a reliable strategy to overcome this limitation. The FSC device is capable to heat and cool a small sample (ng-range) with ultrafast rates of several ten thousand K/s. Evidence of a glass transition is obtained for a series of PIMs with different chain rigidities. Local small-scale fluctuations are held responsible for the glass transition of highly rigid PIMs rather than segmental motions as in conventional polymers. T2 - International Polymer Processing Society (PPS) - Europe-Africa 2019 Regional Conference (PPS2019) CY - Pretoria, South Africa DA - 18.11.2019 KW - Polymers KW - Polymers of intrinsic microporosity KW - Glass transition KW - Fast scanning calorimetry PY - 2019 AN - OPUS4-49957 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liehr, Sascha T1 - Real-time dynamic strain sensing in optical fibers using artificial neural networks N2 - The use of artificial neural networks (ANNs) is demonstrated for efficient real-time data processing in optical fiber sensing applications. Using ANN-based algorithms, two orders of magnitude improved computation time and improved measurement resolution is achieved for distributed strain sensing using the wavelength-scanning coherent optical time domain reflectometry technique. T2 - WORKSHOP - Machine learning in optical analytics CY - Berlin, Germany DA - 13.11.2019 KW - Artificial neural networks KW - Distributed acoustic sensing (DAS) KW - Distributed vibration sensing KW - Signal processing PY - 2019 AN - OPUS4-49869 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Qiao, Linan A1 - Keller, Christian A1 - Zencker, Uwe A1 - Völzke, Holger T1 - Three-dimensional finite element analysis of O-ring metal seals considering varying material properties and different seal diameters N2 - Metal seals of O-ring form are often used in lid-systems of transport and storage casks for radioactive waste in Germany. To investigate their mechanical behaviour, three dimensional (3D) finite element (FE) models were created using solid elements for all of the seal components. The material behaviour of each component is described with a unified static elastic-plastic material model. The total strain is defined as the sum of linear elastic strain and plastic strain with power-law hardening. The model was carefully validated by comparison of Simulation results with experimental results. The influence of material fluctuation of each seal component due to varying properties and the sensitivity of different seal diameters on the seal force are analysed and discussed. The results show that the material properties of helical spring have major influence on seal force and that the influence of seal diameters is negligible small in the studied range. This is very important to use the test results from seals with small diameter for the assessment of seal behaviour with larger diameter as used in transport and storage cask. KW - Sensitivity analysis KW - Transport and storage cask KW - O-ring metal seal KW - Lid-system KW - Finite element analysis KW - Stochastic variation of material properties PY - 2019 DO - https://doi.org/10.1016/j.ijpvp.2019.103953 VL - 176 SP - 102953 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-49263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nerger, Deborah A1 - Hille, Falk A1 - Moosavi, Robabeh A1 - Grunwald, Marcel A1 - Redmer, Bernhard A1 - Kühn, T. A1 - Hering, M. A1 - Bracklow, F. T1 - Improved tomographic investigation for impact damage characterization N2 - Reinforced concrete (RC) is used as structural material in most diverse civil engineering applications. For the variability of its physical properties it is still an engineering challenge to meet all necessary requirements for the prediction of dynamic effects under impact loading. In this paper, investigations are shown within the scope of quantifying and evaluating the damage caused by an impact. The experimental investigations are performed in the field of low- and medium-velocity impact. The chosen flat nose shape results in small penetrations on the top side and scabbing on the bottom side. The plate is scanned with an adapted planar tomographic examination after the impact, and the damage is analysed, afterwards. Cracks and spalling are made visible with a reconstruction. The numerical model validated on the tomographic results justifies the application for further predictions of the damage description. T2 - 25th International Conference on Structural Mechanics in Reactor Technology - SMIRT25 CY - Charlotte, NC, USA DA - 04.08.2019 KW - Impact KW - Damage characterization KW - Planar tomography KW - Numeric simulation KW - Reinforced concrete structure PY - 2019 SP - Paper Div 5 S8, 1 EP - 9 AN - OPUS4-49541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Laser-induced periodic surface structures N2 - This presentation reviews the current state in the field of Laser-induced Periodic Surface Structures (LIPSS). These surface nanostructures are a universal phenomenon and can be generated on almost any material by irradiation with intense linearly polarized laser radiation. LIPSS are formed in a “self-ordered” way and are often accompanying material processing applications. They can be produced following a single-step process and enable surface functionalization through the adaption of optical, mechanical and chemical surface properties. Their structural sizes typically range from several micrometers down to less than 100 nanometers exhibiting a clear correlation with the polarization direction of the laser radiation. Various types of surface structures are classified, relevant control parameters are identified, and their material specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics, through time-resolved optical experiments and theoretical simulations. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed. T2 - Seminar CY - Laser-Laboratorium Göttingen e.V., Germany DA - 18.11.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - Electromagnetic radiation KW - Applications KW - Femtosecond laser ablation PY - 2019 AN - OPUS4-49689 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Quo vadis LIPSS? – Recent developments in theoretical modelling and technical applications N2 - This presentation reviews current and expected developments in the field of laser-induced periodic surface structures (LIPSS, ripples). These surface nanostructures are a universal phenomenon and can be generated on almost any material by irradiation with intense linearly polarized radiation. LIPSS are formed in a “self-ordered” way and are often accompanying laser material processing applications. The structures can be produced in a single-step process and enable surface functionalization through the adaption of optical, mechanical and chemical surface properties. Their spatial periods typically range from several micrometers down to less than 100 nanometers, exhibiting a clear correlation with the polarization direction of the laser radiation used. Various types of LIPSS have been classified, relevant control parameters were identified, and material specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics, through time-resolved optical experiments and theoretical simulations. Special attention will be paid to a comparison of the currently available formation theories for LIPSS with a discussion of their respective strengths and weaknesses. Currrently explored applications featuring surface functionalization in the fields of optics, surface wetting, medicine, and tribology will be discussed. T2 - 9th International LIPSS Workshop CY - Ljubljana, Slovenia DA - 26.09.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - Femtosecond laser ablation KW - Modelling KW - Applications PY - 2019 AN - OPUS4-49708 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo A1 - Kirner, Sabrina V. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Quo vadis LIPSS? – Applications of laser-induced periodic surface structures N2 - Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon that can be observed on almost any material after the irradiation by linearly polarized laser beams, particularly when using ultrashort laser pulses with durations in the femtosecond to picosecond range. During the past years significantly increasing industrial and research activities have been reported in the field of LIPSS, since their generation in a single-step process provides a simple way of nanostructuring and surface functionalization towards the control of optical, mechanical or chemical surface properties. In this contribution the mechanisms of formation and current trends and applications of LIPSS are reviewed, including the colorization of technical surfaces, the control of surface wetting properties, the mimicry of the natural texture of animals, the tailoring of surface colonization by bacterial biofilms, the advancement of leadless medical pacemakers, and the improvement of the tribological performance of nanostructured metal surfaces. T2 - 11. Mittweidaer Lasertagung CY - Mittweida, Germany DA - 13.11.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser ablation KW - Surface functionalization KW - Applications PY - 2019 VL - 3/1 SP - 41 EP - 43 PB - Hochschule Mittweida CY - Mittweida AN - OPUS4-49673 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tschirschwitz, Rico T1 - Lithium Ion Batteries - Europe and Germany in general and BAM with safety aspects in particular N2 - The article introduces the BAM as well as the experimental possibilities at the BAM TTS in the first part. The second part explains general aspects of the electromobility strategy and the research landscape on lithium batteries in Germany and Europe. In the last part of the presentation current investigations on the safety of lithium batteries as well as perspectives planned investigations of the BAM in this area are presented. T2 - Workshop with KGS (Korea Gas Safety Corporation) and KEPCO (Korea Electric Power Corporation) Reserach Institute on Lithim Battery Safety CY - Seoul, South Korea DA - 11.11.2019 KW - Lithium battery KW - Thermal runaway KW - Gas analysis KW - BAM TTS KW - European Electromobility PY - 2019 AN - OPUS4-49725 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo T1 - Oxidation effects on the functionality and formation of laser-induced periodic surface structures N2 - In the last decades, the formation of laser-induced periodic surface structures (LIPSS) has been widely studied, not only to stablish a general understanding of the main mechanisms present during the irradiation with ultrashort laser pulses, but also to identify the main processing parameters for its fabrication on various technical materials. However, an important and almost always present effect that is typically set aside is the material oxidation during or after the laser processing. Usually, this leads to optical, chemical, structural and mechanical alterations that are seldomly studied in detail. Therefore, in this work we present a study that includes the formation of LIPSS on Ti6Al4V alloy for tribological applications were different oxidations layers are involved. The material characterization using different techniques, such as energy dispersive X-ray analyses (EDX), X-ray photoelectron spectroscopy (XPS), micro Raman spectroscopy (µ-RS), and depth-profiling Auger electron microscopy (AEM), and other techniques, confirms the formation of a non-negligible superficial oxide layer – strongly dependent on the specific processing parameters. We perform tribological experiments on laser irradiated samples oxidized by alternative ways to have a comparison on its friction performance. The obtained results show significant differences that depend directly on the thickness and the quality of the oxidized layer. This may open a fertile research area until now barely explored with clear impact on LIPSS based applications. T2 - 9th International LIPSS Workshop CY - Ljubljana, Slovenia DA - 26.09.2019 KW - Laser-induced periodic surface structures (LIPSS) PY - 2019 AN - OPUS4-49709 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gräf, S. T1 - Large-area fabrication of low- and high-spatial-frequency laser-induced periodic surface structures on carbon fibers N2 - The properties of fiber-reinforced polymers (CFRP) or concretes (ECC) strongly depend on the interface between the fiber and the surrounding matrix. Different methods such as plasma oxidation, chemical or electrolytic etching and chemical vapor deposition have been investigated to increase, for example, the bonding strength. The present study deals with the functionalization of the fiber surface based on laser-induced periodic surface structures (LIPSS). They can be characterized as a modulation of the surface topography on the nano- and microscale that results from the irradiation of the surface with linearly polarized laser radiation close to the ablation threshold. According to their spatial period, LIPSS are classified into low-spatial frequency LIPSS (LSFL) and high-spatial frequency LIPSS (HSFL). The great potential of both types of LIPSS structures regarding functional surface properties was demonstrated in numerous investigations. The objective of the present study was the homogenous manufacturing of both types of LIPSS on large areas of carbon fiber arrangements without damage. The results are discussed based on a detailed analysis of the topographic and chemical surface properties. T2 - 15th International Conference on Laser Ablation (COLA 2019) CY - Hawaii, USA DA - 08.09.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Carbon fibers KW - Femtosecond laser ablation KW - Surface functionalization PY - 2019 AN - OPUS4-49676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nerger, Deborah T1 - Post-impact evaluation at RC plates with planar tomography and FEM N2 - Due to the many possible applications, the uncomplicated production and the high application range, reinforced concrete is a widely used building material. This large range of physical material properties still poses an engineering challenge in determining all necessary requirements for predicting dynamic effects under impact load. Many aspects of impact have already been examined and some correlations have been studied intensively. Examples are the work of Lastunen and Booker, who studied the influence of projectile properties on the impact form. Li has also investigated the local effects of an impact. The field of detailed damage analysis has not been in focus so far. This presentation shows some studies in medium-velocity impact with the focus on post-impact damage evaluation. The impactor is modified so that the test plates show low penetration on the top and scabbing on the bottom. With the unique tomography lab test stand at BAM the plate is scanned after the impact and the damage is analyzed. Cracks and scabbing are made visible with a reconstruction. The comparison of simulation and tomography allows to create prognosis models for damage characterization. T2 - 36th Danubia Adria Symposium on Advances in Experimental Mechanics CY - Pilsen, Czech Republic DA - 24.09.2019 KW - Impact KW - Damage characterization KW - Planar tomography KW - Numeric simulation KW - Reinforced concrete structure PY - 2019 AN - OPUS4-49691 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baer, Wolfram T1 - Chunky graphite in ferritic spheroidal graphite cast iron: Formation, prevention, characterization, impact on properties – An overview N2 - Ferritic spheroidal graphite cast iron (SGI) materials have a remarkable technical poten-tial and economic impact in modern industry. These features are closely related to the question of how the cast materials can be produced without structural defects and graphite degenerations such as for example chunky graphite. Although the chunky graphite degeneration superficially seems to be well known, its metallurgical background is still controversially discussed, appropriate field-tested non-destructive tools for its quantification in castings are lacking and the knowledge on its impact on material properties is fairly limited. Addressing this status, the article is providing a current overview on the subject. Existing theories on formation and growth mechanisms of chunky graphite are briefly reviewed. Furthermore, from a metallurgical point of view, causes for the appearance of chunky graphite as well as preventive measures are concisely summarized. Particular attention is paid to the morphology of chunky graphite and how it can be characterized by destructive and non-destructive techniques. Special emphasis was laid on providing a comprehensive overview on the impact of chunky graphite on strength, ductility, fatigue limit, fatigue crack growth rate as well as fracture tough-ness of ferritic SGI materials based on experimental data. Moreover, conclusions for the assessment of castings affected by chunky graphite are drawn. KW - Characterization KW - Ferritic spheroidal graphite cast iron KW - Chunky graphite KW - Properties KW - Formation KW - Prevention PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499972 DO - https://doi.org/10.1007/s40962-019-00363-8 SN - 1939-5981 SN - 2163-3193 VL - 14 IS - 2 SP - 454 EP - 488 PB - Springer Verlag AN - OPUS4-49997 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Quercetti, Thomas A1 - Scheidemann, Robert A1 - Komann, Steffen A1 - Ballheimer, Viktor A1 - Wille, Frank T1 - Drop Testing of a New Package Design for the Transport of SNF from German Research Reactors N2 - A new dual purpose cask design was developed for the safe transport and interim storage of spent fuel elements of German research reactors. In the framework of the safety assessment within the package approval procedure the Bundesanstalt für Materialforschung und –prüfung (BAM) as competent authority performed a series of drop tests according with the IAEA Transport Regulations. The package consists of a cylindrical thick-walled ductile cast iron cask body closed by a bolted lid system with metallic seals. A lid and bottom sided impact limiter consisting of a wood/steel construction limit the mechanical impact loading. The full-scale test specimen was equipped with a basket and assembled with dummy-fuel elements. The package and test specimen, respectively have a total mass of approximately 24 metric tons. The mechanical drop test program included three 9m free drop tests, in horizontal, vertical and oblique cask orientation onto the lid system. Additionally, a 1m-puncture bar drop test followed the horizontal drop test to consider an IAEA-drop test sequence. The horizontal and vertical drop tests were performed at a temperature of minus 40°C. During the oblique drop test the upper impact limiter was heated up to +80°C. The tests were conducted onto an unyielding target, fulfilling the IAEA requirements. The test specimen was considerably instrumented with strain gauges and accelerometers. Transient strains at selected locations of the inner and outer container walls, of the primary and secondary lid, as well as of the corresponding lid bolts were measured during the drop tests. Furthermore, decelerations in different locations at the cask body and the lids were measured. The complex geometrical deformation of the impact limiters due to the impact were determined by optical 3D- measurements. Before and after the drop tests the leakage rate of the lid system was determined by helium leakage testing. The experimental results contribute to the evaluation of the package response to mechanical tests, demonstrating safety under normal and accident conditions of transport and especially to the verification of the dynamic finite-element model of the package used in the package design safety report. T2 - PATRAM 2019 CY - New Orleans, LA, USA DA - 04.08.2019 KW - SNF KW - Drop testing KW - New package design PY - 2019 SP - Paper 19-A-1142,1 EP - 10 AN - OPUS4-50622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Anita T1 - Alles über Lithiumbatterien (I) N2 - Der Auftakt der Artikelserie beschäftigt sich mit den neuen Verpackungsvorschriften für defekte Lithiumbatterien, die beim Transport gefährlich reagieren können. Die Antworten auf die wichtigsten Fragestellungen. KW - Gefahrgutverpackungen KW - Lithiumbatterien KW - Gefahrgut KW - ADR PY - 2019 SN - 0016-5808 VL - 2019 IS - 06 SP - 20 EP - 23 PB - Storck Verlag CY - Hamburg AN - OPUS4-50800 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Qiao, Linan T1 - A New Time-Temperature Equivalent Formulation for the Description of Thermo-rheologically Complex Behaviour N2 - Compared with the original time-temperature superposition (TTS) principle, an extended non-linear time-temperature equivalent (TTE) principle is suggested in this work. Results shown us, all application of TTS and most of the TTE parameters, for example, the Orr-Sherby-Dorn, Manson-Succop, Larson-Müller, Manson-Haferd, Mendelson-Roberts-Manson parameters and the more general ‘single metamodel’ from Haque–Stewart are special cases of the new suggested principle. The merits of this new method are discussed. T2 - 4th International Conference on Rheology and Modeling of Materials CY - Miskolc-Lillafüred, Hungary DA - 07.10.2019 KW - Scale/shift factor and form/stretchFactor of time-temperature relation KW - Time-temperature superposition/equivalent principle KW - Thermo-rheologically simple/complex behaviour PY - 2019 AN - OPUS4-50772 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Anita T1 - Aktuelle Forschung - Technik für sichere Gefahrguttransporte N2 - Lithiumbatterien, Tanks und Druckgasflaschen: Ihnen ist gemeinsam, dass Gefahrguttransporte mit Ihnen sicher erfolgen müssen. Um dies zu gewährleisten, führt die BAM verschiedene Untersuchungen und Forschungsvorhaben durch. T2 - 35. Internationale Gefahrgut-Tage Hamburg CY - Hamburg, Germany DA - 17.02.2019 KW - Lithiumbatterien KW - Druckgefäße KW - Gefahrguttransport KW - ADR KW - Sicherheit PY - 2019 AN - OPUS4-50802 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Anita T1 - Aktuelles zur Sicherheit von Lithium-Ionen Akkus - Lagerung, Transporte, Brandschutzkonzepte N2 - Sicherheitskonzepte werden für die verschiedenen Szenarien für Lithiumakkus benötigt: Vor allem für den Bereich der Lagerung gibt es im Moment nur wenige Vorgaben. Im Vortrag werden verschiedene Brandschutzkonzepte vorgestellt. Für die Lagerung werden Empfehlungen ausgesprochen, die teilweise an die Vorgaben der Transportvorschriften anknüpfen. T2 - Forum 2019 zur Schadenverhütung der Arbeitsgemeinschaft Berlin Brandenburg (AGS) und AGBB Berlin e.V. CY - Berlin, Germany DA - 23.10.2019 KW - Lithiumbatterien KW - Brandschutzkonzepte KW - Lagerung KW - Gefahrguttransport PY - 2019 AN - OPUS4-50807 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Anita T1 - Zulassungsregeln für Verpackungen von Lithiumbatterien N2 - Sicherer Transport defekter Batterien im Aufgabenbereich der BAM. T2 - 12. Fachkonferenz Lithiumbatterien CY - Frankfurt a.M., Germany DA - 21.01.2019 KW - Lithiumbatterien KW - ADR KW - Gefahrguttransport PY - 2019 AN - OPUS4-50803 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Anita T1 - New ADR regulations for critical lithium batteries N2 - End of life batteries may be damaged or defective and may cause the risk of dangerous reactions. New ADR regulations allow them nevertheless to be tansported with the specifications of the national competent authority. BAM's approach. T2 - End-of-Life Batteries from Electrified Vehicles CY - Fredrikstad Oslo, Norway DA - 13.06.2019 KW - Dangerous goods KW - Defective Lithium batteries KW - ADR KW - Transport PY - 2019 AN - OPUS4-50801 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Linnemann, Konrad T1 - Experimental and numerical analyses of spent nuclear fuel behavior under transport conditions N2 - Packages for the transport of spent nuclear fuel shall meet the International Atomic Energy Agency regulations to ensure safety under different transport conditions. The physical state of the spent fuel and the fuel rod cladding as well as the geometric configuration of fuel assemblies are important inputs for the evaluation of the package capabilities under these conditions. The mechanical behavior of spent fuel assemblies shall be analyzed with regard to the assumptions which are used in the containment and criticality safety analysis. The package as a mechanical system is characterized by a complex set of interactions, e. g. between the fuel rods within the assembly as well as between the fuel assemblies, the basket, and the cask containment. This complexity makes it difficult to assume appropriate mechanical loads for the spent fuel inside the package. Another challenge is the assumption of material properties which represent the variation of the fuel rods regarding cladding material, burn-up and the operation history sufficiently. The objective of this paper is to give an overview about the current approaches and research for the evaluation of spent fuel behavior within the package design approval procedure. In this context, analytical, numerical and experimental results are discussed. The presented work is achieved within a collaboration of BAM with national and international partners. T2 - Abteilungskolloquium 3.3 CY - Berlin, BAM Fabeckstraße DA - 02.10.2019 KW - Transportbehälter KW - Radioaktive Stoffe KW - Brennelementverhalten KW - FE-Berechnungen PY - 2019 AN - OPUS4-51173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Quercetti, Thomas T1 - Drop Testing of a New Package Design for the Transport of SNF from German Research Reactors N2 - A new dual purpose cask design was developed for the safe transport and interim storage of spent fuel elements of German research reactors. In the framework of the safety assessment within the package approval procedure the Bundesanstalt für Materialforschung und –prüfung (BAM) as competent authority performed a series of drop tests according with the IAEA Transport Regulations. The package consists of a cylindrical thick-walled ductile cast iron cask body closed by a bolted lid system with metallic seals. A lid and bottom sided impact limiter consisting of a wood/steel construction limit the mechanical impact loading. The full-scale test specimen was equipped with a basket and assembled with dummy-fuel elements. The package and test specimen, respectively have a total mass of approximately 24 metric tons. The mechanical drop test program included three 9m free drop tests, in horizontal, vertical and oblique cask orientation onto the lid system. Additionally, a 1m-puncture bar drop test followed the horizontal drop test to consider an IAEA-drop test sequence. The horizontal and vertical drop tests were performed at a temperature of minus 40°C. During the oblique drop test the upper impact limiter was heated up to +80°C. The tests were conducted onto an unyielding target, fulfilling the IAEA requirements. The test specimen was considerably instrumented with strain gauges and accelerometers. Transient strains at selected locations of the inner and outer container walls, of the primary and secondary lid, as well as of the corresponding lid bolts were measured during the drop tests. Furthermore, decelerations in different locations at the cask body and the lids were measured. The complex geometrical deformation of the impact limiters due to the impact were determined by optical 3D- measurements. Before and after the drop tests the leakage rate of the lid system was determined by helium leakage testing. The experimental results contribute to the evaluation of the package response to mechanical tests, demonstrating safety under normal and accident conditions of transport and especially to the verification of the dynamic finite-element model of the package used in the package design safety report. T2 - PATRAM 2019 CY - New Orleans, LA, USA DA - 04.08.2019 KW - SNF KW - Drop testing KW - New package design PY - 2019 AN - OPUS4-50623 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kreft, S. A1 - Radnik, Jörg A1 - Agostini, G. A1 - Pohl, M.-M. A1 - Gericke, E. A1 - Hoell, Armin A1 - Beller, M. A1 - Junge, H. A1 - Wohlrab, S. T1 - Dye activation of heterogeneous Copper(II)-Species for visible light driven hydrogen generation N2 - Heterogeneous Cu catalysts are widely used in photocatalytic hydrogen generation. The typical working mode includes the transfer of photo-induced charges from a semiconductor to CuO which itself is reduced to Cu2O to initiate the catalytic cycle. In this contribution a photosensitizer (dye), excited by visible light absorption, was used to transfer an electron to the CuO which after reduction catalyzes the water reduction to hydrogen. Several copper(II)-catalysts on high surface silica were prepared by impregnation or precipitation and applied in photocatalytic water reduction. The best catalyst CuO(Cl0.1)/SiO2, synthesized via incipient wetness impregnation of CuCl2 in MCM-41 and a following precipitation with NaOH, achieved a 6 times higher activity (1702 mmol h-1 g-1) compared to a previously investigated copper system (280 mmol h-1 g-1 for CuI) under the same reaction conditions. All materials were fully characterized by XRD, TEM and N2 sorption and further by magnetic resonance and X-ray methods EPR, ASAXS and XAS. In situ measurements evidenced a reduction of the initial Cu(II)-species, which confirms the (proposed) photocatalytic mechanism. KW - Hydrogen generation KW - CuO nanoparticles KW - Molecular sieves PY - 2019 DO - https://doi.org/10.1016/j.ijhydene.2019.04.006 VL - 44 IS - 53 SP - 28409 EP - 28420 PB - Elsevier Ltd. AN - OPUS4-49350 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tschirschwitz, Rico T1 - Auswirkungen beim Versagen von Energiespeichern - Druckbehälter und Lithium-Ionen-Batterien N2 - Immer wieder kommt es bei Bränden zum Bersten von Propan- und Acetylenflaschen. Im Falle eines Behälterversagens stellen diese eine enorme Gefährdung für die Einsatzkräfte dar. Die BAM beschäftigt sich seit vielen Jahren mit den Auswirkungen im Falle eines solchen Behälterversagens. Der erste Teil des Beitrages stellt die Arbeit der BAM auf diesem Gebiet vor und zeigt verschiedene Handlungsoptionen auf, um das Risiko für Einsatzkräfte zu verringern. Im zweiten Teil des Beitrages werden die aktuellen Aufgaben und bisherigen Aktivitäten zur Sicherheit von Lithiumbatterien vorgestellt. Weiterhin werden die Versuchsmöglichkeiten auf dem BAM TTS und die derzeit im Aufbau befindlichen messtechnischen Systeme zur Quantifizierung der Auswirkungen beim Versagen von Lithiumbatterien dargestellt. T2 - Gemeinsame Fortbildungsveranstaltung der Fachvereinigung Arbeitssicherheit e. V. sowie der gesetzlichen Unfallversicherungen, Berufsgenossenschaften der Bauwirtschaft Berlin CY - Berlin, Germany DA - 24.10.2019 KW - Behälterversagen KW - LPG KW - Lithiumbatterien KW - Alternative Antriebe KW - Auswirkungsbetrachtung PY - 2019 AN - OPUS4-49476 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mezera, M. A1 - Bonse, Jörn A1 - Römer, G.R.B.E. T1 - Influence of Bulk Temperature on Laser-Induced Periodic Surface Structures on Polycarbonate N2 - In this paper, the influence of the bulk temperature (BT) of Polycarbonate (PC) on the occurrence and growth of Laser-induced Periodic Surface Structures (LIPSS) is studied. Ultrashort UV laser pulses with various laser peak fluence levels F_0 and various numbers of overscans (N_OS) were applied on the surface of pre-heated Polycarbonate at different bulk temperatures. Increased BT leads to a stronger absorption of laser energy by the Polycarbonate. For N_OS < 1000 High Spatial Frequency LIPSS (HSFL), Low Spatial Frequency LIPSS perpendicular (LSFL-I) and parallel (LSFL-II) to the laser polarization were only observed on the rim of the ablated tracks on the surface but not in the center of the tracks. For N_OS ≥ 1000 , it was found that when pre-heating the polymer to a BT close its glass transition temperature (T_g), the laser fluence to achieve similar LIPSS as when processed at room temperature decreases by a factor of two. LSFL types I and II were obtained on PC at a BT close to T_g and their periods and amplitudes were similar to typical values found in the literature. To the best of the author’s knowledge, it is the first time both LSFL types developed simultaneously and consistently on the same sample under equal laser processing parameters. The evolution of LIPSS from HSFL, over LSFL-II to LSFL I, is described, depending on laser peak fluence levels, number of pulses processing the spot and bulk temperature. KW - Laser-induced periodic surface structures (LIPSS) KW - Polycarbonate KW - Bulk temperature KW - Ultrashort laser pulses PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498242 UR - https://www.mdpi.com/2073-4360/11/12/1947 DO - https://doi.org/https://doi.org/10.3390/polym11121947 SN - 2073-4360 VL - 11 IS - 12 SP - 1947 PB - MDPI CY - Basel, Switzerland AN - OPUS4-49824 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Paulus, Daniel A1 - Bresch, Sophie A1 - Moos, Ralf A1 - Schönauer-Kamin, Daniela T1 - Powder aerosol deposited calcium cobaltite as textured P-type thermoelectric material with power factors approaching single crystal values N2 - In this work, the thermoelectric material calcium cobaltite Ca3Co4O9 (CCO), a promising p-type conducting thermoelectric oxide with anisotropic properties, was processed by the powder aerosol deposition method (PAD) to form a dense ceramic CCO film with a thickness in the µm range. The prepared films were characterized regarding their microstructure and thermoelectric properties between room temperature and 900 °C. After heat treatment at 900 °C, the CCO PAD film in-plane shows excellent properties in terms of electrical conductivity (280 S/cm at 900 °C) and Seebeck coefficient (220 µV/K at 900 °C). The calculated power factor in-plane (ab) reaches with 1125 µW/(m K2) 40 % of the single crystal value, surpassing the known-properties of CCO bulk ceramics. Examination of the microstructure shows a strong fiber texture of the film as well as a strong coarsening of the grains during the first heat treatment up to 900 °C. KW - thermoelectrics KW - calcium cobaltite KW - thermoelectric oxide KW - aerosol deposition method (ADM) PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606246 DO - https://doi.org/10.1016/j.jeurceramsoc.2024.116717 SN - 0955-2219 VL - 44 IS - 15 SP - 1 EP - 8 PB - Elsevier BV AN - OPUS4-60624 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel T1 - In situ bragg edge imaging with neutrons for crystallographic phase and temperature field mapping during tig welding N2 - In Neutron-Bragg-Edge Imaging (NBEI) experiments, we studied the phase transition during butt-welding of martensitic Low Temperature Transformation (LTT) Steel [1]. Tungsten inert gas (TIG) welding was used with a moveable torch allowing for automated weldments. The austenitization in the heat affected zone (HAZ) underneath the welding head could be clearly visualized at λ = 0.39 nm, a wavelength smaller than the Bragg edge wavelengths of both austenite and martensite. Also, the re-transformation upon cooling from austenite into martensitic phase was detected. However, we observed an unexpected additional change in transmission at λ = 0.44 nm that is a wavelength larger than the wavelength of the Bragg edges of both the martensitic and austenitic phases. We attribute this change to the Deybe-Waller-Factor that describes the temperature dependence of coherent scattering at a crystal lattice [2]. The observed two-dimensional attenuation map corresponds well with a temperature distribution modelling by software macros in ANSYS [3]. Here, the absolute temperature values could be achieved by calibrating the modelled attenuation with help of a thermocouple placed at the steel sample plate. This allows in return for a direct two-dimensional temperature reading based on the Debye-Waller-relation between neutron attenuation and sample temperature. T2 - MSE 2024 CY - Darmstadt, Germany DA - 24.09.2024 KW - In situ neutron Bragg edge imaging KW - Temperature field mapping KW - Crystallographic phase mapping KW - TIG welding PY - 2024 AN - OPUS4-61268 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bresch, Sophie T1 - Reaction sintering and sintering additives for cost-effective production of thermoelectric oxides N2 - Thermoelectric oxides attract much interest recently. Although their thermoelectric properties are inferior to non-oxides, they exhibit distinct advantages. Thermoelectric oxides are stable in air at higher temperatures, their raw materials are less toxic, and more abundant. To enhance attractivity of these materials for industrial applications, production costs need to be reduced. Conventionally, the legs of thermoelectric generators are sintered from green bodies of previously synthesized powder. Reaction-sintering is a fabrication method without a powder synthesis step, as the final phase is formed during the sintering from a raw material mixture. Moreover, the reduction of chemical potential during reaction-sintering is effective as an additional driving force for sintering. We show that reaction-sintering increases the densification of CaMnO3 (n-type, Sm doped). Consequently, the electrical conductivities improved by about 100 % leading to superior power factors (PF = 230 µW/mK² for CaMnO3). Another approach to reduce the production costs is to lower the sintering temperature by adding sinter additives. The addition of 4 wt% CuO to CaMnO3 lowers the sinter temperature from 1250 °C to 1050 °C. The achieved power factor PF = 264 µW/mK is more than two times higher as reported in literature for the same dopant. T2 - Virtual Conference on Thermoelectrics (VCT) CY - Online meeting DA - 21.07.2020 KW - Thermoelectrics KW - Reaction sintering KW - Sintering additives KW - Calcium manganate KW - Calcium cobaltite PY - 2020 AN - OPUS4-51070 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bresch, Sophie T1 - Improved thermoelectric properties of CaMnO3 and Ca3Co4O9 by increasing the driving force for sintering N2 - Thermoelectric materials can convert waste heat directly into electrical power by utilizing the Seebeck effect. Calcium cobaltite (Ca3Co4O9, p-type) and calcium manganate (CaMnO3, n-type) are two of the most promising oxide thermoelectric materials. The performance of these materials is evaluated by the power factor PF = S²∙σ and the figure of merit ZT = (PF ∙ T) / κ, demanding high Seebeck coefficient S, high electrical conductivity σ and low thermal conductivity κ. The latter two are increasing with increasing relative sinter density. According to theory, the relative density of ceramics can be improved by increasing the driving force for sintering. This study investigates different approaches to increase the driving force for sintering of Ca3Co4O9 and CaMnO3 to improve densities and thermoelectric properties. The following approaches were applied: minimizing the energy input during powder synthesis by calcination, fine milling of the powder, using reaction-sintering without a powder synthesis step, and adding a transient liquid phase by sinter additives. All different approaches led to an increased densification and thus higher electrical conductivity and higher PF. Thermal conductivity increased as well but not to the same extent. E.g. reaction-sintering increased the densification of Ca3Co4O9 (p-type) and CaMnO3 (n-type). Consequently, the electrical conductivities improved by about 100 % for both oxides leading to superior power factors (PF = 230 µW/mK² for CaMnO3). Although the thermal conductivity increased as well by 8 %, the figures of merit (ZT) were significantly higher compared to conventionally sintered bars. The addition of 4 wt% CuO as a sinter additive to CaMnO3 lowers the sinter temperature from above 1250 °C to below 1100 °C and increases the relative density. Due to the increased density, both electrical conductivity and PF increased by more than 200 % even though the sintering temperature was 150 K lower. T2 - Electroceramics XVII CY - Online meeting DA - 24.08.2020 KW - Thermoelectrics KW - Reaction sintering KW - Sintering additives PY - 2020 AN - OPUS4-51163 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Risse, S. A1 - Juhl, A. A1 - Mascotto, S. A1 - Arlt, T. A1 - Markötter, Henning A1 - Hilger, A. A1 - Manke, I. A1 - Fröba, M. T1 - Detailed and Direct Observation of Sulfur Crystal Evolution During Operando Analysis of a Li-S Cell with Synchrotron Imaging N2 - Herein, we present a detailed investigation of the electrochemically triggered formation and dissolution processes of α- and β-sulfur crystals on a monolithic carbon cathode using operando high-resolution synchrotron radiography (438 nm/pixel). The combination of visual monitoring with the electrical current response during cyclic voltammetry provides valuable insights into the sulfur formation and dissolution mechanism. Our observations show that the crystal growth process is mainly dictated by a rapid equilibrium between long-chain polysulfides on one side and solid sulfur/short-chain polysulfides on the other side, which is consistent with previous studies in this field. The high temporal and spatial resolution of synchrotron imaging enables the observation of different regimes during the sulfur formation and dissolution process. The appearance of short-chain polysulfides after the first anodic CV peak initiates a rapid dissolution process of α-sulfur crystals on the cathode. The increase in the long-chain lithium polysulfide concentration at the cathode surface during charge results in an increased crystal growth rate, which in turn produces imperfections in α- and β-sulfur crystals. There are strong indications that these defects are fluid inclusions, which may trap dissolved polysulfides and therefore reduce the electrochemical cell capacity. KW - LiS battery KW - Radiography KW - Synchrotron Imaging PY - 2020 DO - https://doi.org/10.1021/acs.jpclett.0c01284 VL - 11 IS - 14 SP - 5674 EP - 5679 AN - OPUS4-51100 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. T1 - Influence of Internal Pressure Regulation During Filament Winding on Failure Mechnism in Type 4 Pressure Vessels: A Case Study N2 - Hydrogen storage is a crucial part of the hydrogen value chain, particularly in terms of safety and social acceptance of hydrogen technologies. For on-board and transportation applications, hydrogen is commonly stored as a compressed gas in pressure vessels. Full composite wrapped Type 4 pressure vessels are especially beneficial due to their high weight-saving potential and their capability to withstand high working pressures. To maintain an appropriate safety level, the mechanical behavior of the composite structure has been the subject of investigation in numerous studies. In this study, the failure mechanisms of two designs of Type 4 cylinders are investigated. The two designs differ solely in the manufacturing process parameters, particularly the internal pressure applied during the filament winding process. Variations in internal pressure result in different residual stress states and changes in the quality of the composite structure. The stacking sequence, materials used, and other manufacturing parameters remain unchanged. The cylinders show different failure mechanisms in slow burst tests: one design fails in hoop windings, while the other one fails in helical windings, despite no stress exaggeration in the fiber direction being observed with embedded optical fibers or in numerical simulations. To explain the failure mechanisms, the quality of the cylinders is investigated. The results of X-ray computed tomography and pulse-echo investigation, highlight the complexity of the interactions between manufacturing process parameters, residual stresses, manufacturing quality, and the mechanical behavior of composite pressure vessels. Resin-rich areas in the composite material are identified as a possible cause of the differing failure mechanisms. T2 - 11th International Conference on Hydrogen Safety ICHS 2025 CY - Seoul, Republic of Korea DA - 22.09.2025 KW - omposite KW - Pressure vessel KW - Filament winding KW - Slow burst test KW - Failure mechanism PY - 2025 AN - OPUS4-64462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mohseninia, A A1 - Eppler, M A1 - Kartouzian, D A1 - Markötter, Henning A1 - Kardjilov, N A1 - Wilhelm, F A1 - Scholta, J A1 - Manke, I T1 - PTFE Content in Catalyst Layers and Microporous Layers: Effect on Performance and Water Distribution in Polymer Electrolyte Membrane Fuel Cells N2 - This work describes the effects of catalyst layers (CLs) consisting of hydrophobic PTFE on the performance and water management of PEM fuel cells. Catalyst inks with various PTFE contents were coated on Nafion membranes and characterized using contact angle measurements, SEX-EDX, and mercury porosimetry. Fuel cell tests and electrochemical impedance spectroscopy (EIS) were conducted under varying operating conditions for the prepared materials. At dry conditions, CLs with 5 wt.% PTFE were advantageous for cell performance due to improved membrane hydration, whereas under humid conditions and high air flow rates CLs with 10 wt.% PTFE improved the performance in high current density region. Higher PTFE contents (⩾20 wt.%) increased the mass transport resistance due to reduced porosity of the CLs structure. Operando neutron radiography was utilized to study the effects of hydrophobicity gradients within CLs and cathode microporous layer (MPLC) on liquid water distribution. More hydrophobic CLs increased the water content in adjacent layers and improved performance, especially at dry conditions. MPLC with higher PTFE contents increased the overall liquid water within the CLs and GDLs and escalated the water transfer to the anode side. Furthermore, the role of back-diffusion transport mechanism on water distribution was identified for the investigated cells. KW - Neutron imaging KW - Polymer Electrolyte Membrane Fuel Cell KW - Catalyst Layer KW - Microporous Layer KW - Water Distribution PY - 2021 DO - https://doi.org/10.1149/1945-7111/abec53 VL - 168 IS - 3 SP - 034509 PB - IOP Science AN - OPUS4-52402 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Popiela, Bartosz A1 - Günzel, Stephan A1 - Sklorz, Christian A1 - Widjaja, Martinus Putra A1 - Mair, Georg W. A1 - Seidlitz, Holger T1 - Application of the incremental hole-drilling method for residual stress determination in type 4 pressure vessels N2 - Hole-drilling method is a standardized technique for obtaining residual stresses in isotropic structures. Previous studies provide a foundation that enables the use of this method to investigate orthotropic structures, such as fiber-reinforced composites. In this study, the incremental hole-drilling method was applied to investigate residual stresses in filament wound type 4 composite pressure vessels. The investigated composite cylinders were manufactured with different internal pressure functions during the winding process, to achieve distinct residual stress states. Additionally, the influence of the initial loading under sustained internal pressure and increased temperature on the stress distribution was investigated. It was shown that the residual stress state can be influenced by varying the internal pressure in the winding process. After testing at sustained load and increased temperature, a stress redistribution was observed, which took place due to creep phenomena. Finally, a discussion of the challenges for the application of the hole-drilling method to composite pressure vessels is provided. KW - Hole-drilling method KW - Filament winding KW - Type 4 composite pressure vessels KW - Residual stresses KW - Stress redistribution PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627765 DO - https://doi.org/10.1515/mt-2024-0328 SN - 2195-8572 VL - 67 IS - 4 SP - 663 EP - 674 PB - Walter de Gruyter GmbH AN - OPUS4-62776 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bevilacqua, N. A1 - Asset, T. A1 - Schmid, M. A. A1 - Markötter, Henning A1 - Manke, I. A1 - Atanassov, P. A1 - Zeis, R. T1 - Impact of catalyst layer morphology on the operation of high temperature PEM fuel cells N2 - Electrochemical impedance spectroscopy (EIS) is a well-established method to analyze a polymer electrolyte membrane fuel cell (PEMFC). However, without further data processing, the impedance spectrum yields only qualitative insight into the mechanism and individual contribution of transport, kinetics, and ohmic losses to the overall fuel cell limitations. The distribution of relaxation times (DRT) method allows quantifying each of these polarization losses and evaluates their contribution to a given electrocatalyst's depreciated performances. We coupled this method with a detailed morphology study to investigate the impact of the 3D-structure on the processes occurring inside a high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC). We tested a platinum catalyst (Pt/C), a platinum-cobalt alloy catalyst (Pt3Co/C), and a platinum group metal-free iron-nitrogen-carbon (Fe–N–C) catalyst. We found that the hampered mass transport in the latter is mainly responsible for its low performance in the MEA (along with its decreased intrinsic performances for the ORR reaction). The better performance of the alloy catalyst can be explained by both improved mass transport and a lower ORR resistance. Furthermore, single-cell tests show that the catalyst layer morphology influences the distribution of phosphoric acid during conditioning. KW - High-temperature polymer electrolyte membrane fuel cell KW - Platinum-free catalyst KW - Mass transport KW - Oxygen reduction reaction KW - Distribution of relaxation times analysis PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520917 DO - https://doi.org/10.1016/j.powera.2020.100042 VL - 7 SP - 100042 PB - Elsevier Ltd. AN - OPUS4-52091 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ziesche, R. F. A1 - Robinson, J. B. A1 - Markötter, Henning A1 - Bradbury, R. A1 - Tengattini, A. A1 - Lenoir, N. A1 - Helfen, L. A1 - Kockelmann, W. A1 - Kardjilov, N. A1 - Manke, I. A1 - Brett, D. J. L. A1 - Shearing, P. R. T1 - Editors’ Choice—4D Neutron and X-ray Tomography Studies of High Energy Density Primary Batteries: Part II. Multi-Modal Microscopy of LiSOCl2 Cells N2 - The ability to track electrode degradation, both spatially and temporally, is fundamental to understand performance loss during operation of lithium batteries. X-ray computed tomography can be used to follow structural and morphological changes in electrodes; however, the direct detection of electrochemical processes related to metallic lithium is difficult due to the low sensitivity to the element. In this work, 4-dimensional neutron computed tomography, which shows high contrast for lithium, is used to directly quantify the lithium diffusion process in spirally wound Li/SOCl2 primary cells. The neutron dataset enables the quantification of the lithium transport from the anode and the accumulation inside the SOCl2 cathode to be locally resolved. Complementarity between the collected neutron and X-ray computed tomographies is shown and by applying both methods in concert we have observed lithium diffusion blocking by the LiCl protection layer and identified all cell components which are difficult to distinguish using one of the methods alone. KW - Lithium-ion battery KW - Room-temperature KW - Thermal runaway KW - Gas evolution KW - Cells PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520890 DO - https://doi.org/10.1149/1945-7111/abbfd9 VL - 167 SP - 140509 PB - IOP Science AN - OPUS4-52089 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bresch, Sophie A1 - Mieller, Björn A1 - Schönauer-Kamin, D. A1 - Moos, R. A1 - Reimann, T. A1 - Giovannelli, F. A1 - Rabe, Torsten T1 - Influence of pressure and dwell time on pressure‐assisted sintering of calcium cobaltite N2 - Calcium cobaltite Ca3Co4O9, abbreviated Co349, is a promising thermoelectric material for high‐temperature applications in air. Its anisotropic properties can be assigned to polycrystalline parts by texturing. Tape casting and pressure‐assisted sintering (PAS) are a possible future way for a cost‐effective mass‐production of thermoelectric generators. This study examines the influence of pressure and dwell time during PAS at 900°C of tape‐cast Co349 on texture and thermoelectric properties. Tape casting aligns lentoid Co349. PAS results in a textured Co349 microstructure with the thermoelectrically favorable ab‐direction perpendicular to the pressing direction. By pressure variation during sintering, the microstructure of Co349 can be tailored either toward a maximum figure of merit as required for energy harvesting or toward a maximum power factor as required for energy harvesting. Moderate pressure of 2.5 MPa results in 25% porosity and a textured microstructure with a figure of merit of 0.13 at 700°C, two times higher than the dry‐pressed, pressureless‐sintered reference. A pressure of 7.5 MPa leads to 94% density and a high power factor of 326 µW/mK2 at 800°C, which is 11 times higher than the dry‐pressed reference (30 MPa) from the same powder. KW - Hot pressing KW - Texture KW - Thermoelectric properties PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515973 DO - https://doi.org/https://doi.org/10.1111/jace.17541 SN - 0002-7820 VL - 104 IS - 2 SP - 917 EP - 927 PB - Wiley Periodicals LLC AN - OPUS4-51597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yao, J. A1 - Zhu, G. A1 - Dong, K. A1 - Osenberg, M. A1 - Hilger, A. A1 - Markötter, Henning A1 - Ju, J. A1 - Sun, F. A1 - Manke, I. A1 - Cui, G. T1 - Progress and Perspective of Controlling Li Dendrites Growth in All-Solid-State Li Metal Batteries via External Physical Fields N2 - Li dendrites penetration through solid electrolytes (SEs) challenges the development of solid-state Li batteries (SSLBs). To date, significant efforts are devoted to understand the mechanistic dynamics of Li dendrites nucleation, growth, and propagation in SEs, and various strategies that aim to alleviate and even inhibit Li dendrite formation have been proposed. Nevertheless, most of these conventional strategies require either additional material processing steps or new materials/layers that eventually increase battery cost and complexity. In contrast, using external fields, such as mechanical force, temperature physical field, electric field, pulse current, and even magnetic field to regulate Li dendrites penetration through SEs, seems to be one of the most cost-effective strategies. This review focuses on the current research progress of utilizing external physical fields in regulating Li dendrites growth in SSLBs. For this purpose, the mechanical properties of Li and SEs, as well as the experimental results that visually track Li penetration dynamics, are reviewed. Finally, the review ends with remaining open questions in future studies of Li dendrites growth and penetration in SEs. It is hoped this review can shed some light on understanding the complex Li dendrite issues in SSLBs and potentially guide their rational design for further development. KW - Li dendrites KW - Li dendrites penetration mechanisms KW - Solid electrolytes KW - Solid-state batteries PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588331 DO - https://doi.org/10.1002/aesr.202300165 SN - 2699-9412 SP - 1 EP - 44 PB - Wiley-VCH CY - Weinheim AN - OPUS4-58833 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Markötter, Henning A1 - Müller, Bernd R. A1 - Kupsch, Andreas A1 - Evsevleev, Sergei A1 - Arlt, T. A1 - Ulbricht, Alexander A1 - Dayani, Shahabeddin A1 - Bruno, Giovanni T1 - A Review of X-Ray Imaging at the BAMline (BESSY II) N2 - The hard X-ray beamline BAMline at BESSY II (Berlin, Germany) has now been in service for 20 years. Several improvements have been implemented in this time, and this review provides an overview of the imaging methods available at the BAMline. Besides classic full-field synchrotron X-ray computed tomography (SXCT), also absorption edge CT, synchrotron X-ray refraction radiography (SXRR), and synchrotron X-ray refraction tomography (SXRCT) are used for imaging. Moreover, virtually any of those techniques are currently coupled in situ or operando with ancillary equipment such as load rigs, furnaces, or potentiostats. Each of the available techniques is explained and both the current and the potential usage are described with corresponding examples. The potential use is manifold, the examples cover organic materials, composite materials, energy-related materials, biological samples, and materials related to additive manufacturing. The article includes published examples as well as some unpublished applications. KW - Material science KW - Radiography KW - Refraction KW - Tomography KW - X-ray imaging PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572417 DO - https://doi.org/10.1002/adem.202201034 SN - 1438-1656 SP - 1 EP - 22 PB - Wiley VHC-Verlag AN - OPUS4-57241 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tiebe, Carlo A1 - Mieller, Björn A1 - Maiwald, Michael A1 - Kipphardt, Heinrich A1 - Tuma, Dirk A1 - Prager, Jens A1 - Schukar, Marcus A1 - Strohhäcker, J. T1 - Sensoren und Analytik für Sicherheit und Prozesskontrolle in Wasserstofftechnologien N2 - Die Nutzung von Sensortechnologien, insbesondere im Bereich der Gasdetektion mit einem Schwerpunkt auf Wasserstoff, spielt eine entscheidende Rolle in verschiedenen Anwendungsbereichen der Wasserstofftechnologie. Sicherheitsüberwachung, Leckdetektion und Prozesskontrolle gehören zu den prominenten Anwendungsgebieten dieser Sensortechnologien. Ein zentrales Ziel ist die Erkennung von freigesetztem Wasserstoff sowie die genaue Bestimmung des Wasserstoff-Luftverhältnisses mithilfe von Gassensoren. Dies ist von entscheidender Bedeutung, um potenzielle Gefahren frühzeitig zu erkennen und angemessene Maßnahmen zu ergreifen. Ein weiterer Schwerpunkt dieses Beitrags liegt auf der Analytik und der Verwendung zertifizierter Referenzmaterialien in Verbindung mit Metrologie für die Wasserstoffspeicherung. Dies gewährleistet eine präzise und zuverlässige Charakterisierung von Wasserstoff und unterstützt die Entwicklung sicherer Speichertechnologien. Im Rahmen des Euramet-Vorhabens Metrology for Advanced Hydrogen Storage Solutions (MefHySto) wird eine Kurzvorstellung präsentiert. Der Vortrag stellt zwei zerstörungsfreie Prüfverfahren zum strukturellen Zustandsüberwachung (Structural Health Monitoring, SHM) für Wasserstofftechnologien vor. Insbesondere die Fehlstellenerkennung mittels geführter Ultraschallwellen spielt eine bedeutende Rolle bei der Lebensdauerüberwachung von Wasserstoffspeichern. Ein weiterer Aspekt ist die Anwendung faseroptischer Sensorik zur Schadensfrüherkennung von Wasserstoffspeichern. Diese zerstörungsfreien Prüfverfahren ermöglichen eine präzise und frühzeitige Identifizierung von Schäden, was die Sicherheit und Effizienz von Wasserstoffspeichersystemen entscheidend verbessert. T2 - DVGW Kongress H2 Sicherheit CY - Online meeting DA - 15.11.2023 KW - H2Safety@BAM KW - Gassensorik KW - Metrologie KW - zertifizierte Referenzmaterialien KW - Zerstörungsfreie Prüfung KW - Ultraschall KW - Faseroptik PY - 2023 AN - OPUS4-59230 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Z. A1 - Dong, K. A1 - Mazzio, K. A. A1 - Hilger, A. A1 - Markötter, Henning A1 - Wilde, F. A1 - Heinemann, T. A1 - Manke, I. A1 - Adelhelm, P. T1 - Phase transformation and microstructural evolution of CuS electrodes in solid-state batteries probed by in situ 3D X-ray tomography N2 - Copper sulfide shows some unique physico-chemical properties that make it appealing as a cathode active material (CAM) for solid-state batteries (SSBs). The most peculiar feature of the electrode reaction is the reversible formation of μm-sized Cu crystals during cycling, despite its large theoretical volume change (75%). Here, the dynamic microstructural evolution of CuS cathodes in SSBs is studied using in situ synchrotron X-ray tomography. The formation of μm-sized Cu within the CAM particles can be clearly followed. This process is accompanied by crack formation that can be prevented by increasing the stack pressure from 26 to 40 MPa. Both the Cu inclusions and cracks show a preferential orientation perpendicular to the cell stack pressure, which can be a result of a z-oriented expansion of the CAM particles during lithiation. In addition, cycling leads to a z-oriented reversible displacement of the cathode pellet, which is linked to the plating/stripping of the Li counter electrode. The pronounced structural changes cause pressure changes of up to 6 MPa within the cell, as determined by operando stack pressure measurements. Reasons for the reversibility of the electrode reaction are discussed and are attributed to the favorable combination of soft materials. KW - Copper sulfide KW - Crack evolution KW - Digital volume correlation KW - Phase transformation KW - Solid-state batteries PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564577 DO - https://doi.org/10.1002/aenm.202203143 IS - 2203143 SP - 1 EP - 12 PB - Wiley VHC-Verlag AN - OPUS4-56457 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bouabadi, Bouchra A1 - Hilger, André A1 - Kamm, Paul H. A1 - Neu, Tillmann R. A1 - Kardjilov, Nikolay A1 - Sintschuk, Michael A1 - Markötter, Henning A1 - Schedel‐Niedrig, Thomas A1 - Abou‐Ras, Daniel A1 - García‐Moreno, Francisco A1 - Risse, Sebastian T1 - Morphological Evolution of Sn‐Metal‐Based Anodes for Lithium‐Ion Batteries Using Operando X‐Ray Imaging N2 - Sn‐based electrodes are promising candidates for next‐generation lithium‐ion batteries. However, it suffers from deleterious micro‐structural deformation as it undergoes drastic volume changes upon lithium insertion and extraction. Progress in designing these materials is limited to complex structures. There is a significant need to develop an alloy‐based anode that can be industrially manufactured and offers high reversible capacity. This necessitates a profound understanding of the interplay between structural changes and electrochemical performance. Here, operando X‐ray imaging is used to correlate the morphological evolution to electrochemical performance in foil and foam systems. The 3D Sn‐foam‐like structure electrode is fabricated in‐house as a practical approach to accommodate the volume expansion and alleviate the mechanical stress experienced upon alloying/dealloying. Results show that generating pores in Sn electrodes can help manage the volume expansion and mitigate the severe mechanical stress in thick electrodes during alloying/dealloying processes. The foam electrode demonstrates superior electrochemical performance compared to non‐porous Sn foil with an equivalent absolute capacity. This work advances the understanding of the real‐time morphological evolution of Sn bulky electrodes. KW - Synchrotron radiation KW - X-ray imaging KW - Lithium-ion battery PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640112 DO - https://doi.org/10.1002/advs.202414892 SN - 2198-3844 VL - 12 IS - 10 SP - 1 EP - 10 PB - Wiley AN - OPUS4-64011 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfaff, Jonas A1 - Schopferer, Sebastian A1 - Markötter, Henning A1 - Rack, Alexander A1 - Bruno, Giovanni A1 - Schmidt, Anita A1 - Tichter, Tim A1 - Böttcher, Nils T1 - High-speed synchrotron radiography of nail penetration-induced thermal runaway: Understanding the explosive behavior of commercial sodium-ion batteries with NFM cathode N2 - The dynamics of mechanically initiated thermal runaway (TR) events in cylindrical 18650 cells with NFM (Na(Ni1/3Fe1/3Mn1/3)O2), LFP (LiFePO4), and NMC532 (LiNi1/2Mn1/3Co1/5O2) cathode chemistries were investigated using high-speed synchrotron X-ray imaging. Structural similarity index measures (SSIM) were employed to identify and track rapid structural changes. In this manner, thermal decompositions and internal propagation dynamics, influencing the safety mechanisms of the cells, were studied. This lead to two major findings: (I) Among NFM, LFP, and NMC532 cells, the TR-characteristics differ significantly in temperature and internal propagation speed. Internal safety mechanisms appear, however, visually similar. Among all samples, LFP cells exhibit higher safety performance concerning the initiation of TR by nail penetration and the progression of TR. (II) The NFM cells used in this study displayed an almost explosive TR. This finding appears counterintuitive on a first glance, since sodium-ion batteries are usually considered safe. High-speed imaging revealed that the explosive TR is not necessarily caused by the thermochemical decomposition reactions, but rather by a failure of the venting mechanism. This results in a significant pressure buildup within the cell upon TR initiation and eventually a severely violent TR. These results underline that battery safety depends on many factors and not solely on optimized cell chemistries or materials. KW - High-speed X-ray radiography KW - Synchrotron X-rays KW - 18650 KW - SIB KW - Na-NFM KW - Structure similarity index measure PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642649 DO - https://doi.org/10.1016/j.powera.2025.100188 SN - 2666-2485 VL - 36 SP - 1 EP - 7 PB - Elsevier Ltd. AN - OPUS4-64264 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Erdmann, Maren A1 - Kupsch, Andreas A1 - Müller, Bernd R. A1 - Hentschel, Manfred P. A1 - Niebergall, Ute A1 - Böhning, Martin A1 - Bruno, Giovanni ED - Erdmann, Maren T1 - Diesel-induced transparency of plastically deformed high-density polyethylene N2 - High-density polyethylene becomes optically transparent during tensile drawing when previously saturated with diesel fuel. This unusual phenomenon is investigated as it might allow conclusions with respect to the material behavior. Microscopy, differential scanning calorimetry, density measurements are applied together with two scanning X-ray scattering techniques: wide angle X-ray scattering (WAXS) and X-ray refraction, able to extract the spatially resolved crystal orientation and internal surface, respectively. The sorbed diesel softens the material and significantly alters the yielding characteristics. Although the crystallinity among stretched regions is similar, a virgin reference sample exhibits strain whitening during stretching, while the diesel-saturated sample becomes transparent. The WAXS results reveal a pronounced fiber texture in the tensile direction in the stretched region and an isotropic orientation in the unstretched region. This texture implies the formation of fibrils in the stretched region, while spherulites remain intact in the unstretched parts of the specimens. X-ray refraction reveals a preferred orientation of internal surfaces along the tensile direction in the stretched region of virgin samples, while the sample stretched in the diesel-saturated state shows no internal surfaces at all. Besides from stretching saturated samples, optical transparency is also obtained from sorbing samples in diesel after stretching. KW - PE-HD Sorption KW - Cavitation KW - Diesel Fuel KW - X-ray refraction KW - WAXS KW - Internal Surfaces KW - Crystal Texture PY - 2019 DO - https://doi.org/10.1007/s10853-019-03700-8 SN - 1573-4803 SN - 0022-2461 VL - 54 IS - 17 SP - 11739 EP - 11755 PB - Springer US CY - US AN - OPUS4-48226 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -