TY - CONF A1 - Zaghdoudi, Maha A1 - Weber, Mike A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Simulation of compression set of epdm o-rings during aging N2 - It is common practice in the application of finite element analysis to model compression set (CS) of elastomers during aging with two different material models according to the two-network theory of Tobolsky. The theory relies on the existence of two networks. The first one represents the original network after vulcanization and is sensitive to chain scission. The second network accounts for the formation of additional crosslinking during aging. Besides the use of user subroutines to describe the two-network model, an element overlay technique is also needed as the full set of both material behaviors did not exist for assignment to a single element. This element overlay technique is valuable for research and developmental purposes but makes extension to industrial usage quite challenging. Our goal is to simulate the CS of elastomers after long-term aging in a commercial finite element software with no need for extra subroutine codes or mesh superposition. Ethylene propylene diene (EPDM) O-rings were aged in a compressed state at 75 °C, 100 °C, 125 °C and 150 °C for up to 183 days. Investigations of the experimental test results were used to identify material models and their parameters to develop a finite element model to simulate CS. The model was implemented in the finite element software ABAQUS/Standard® with a sequential temperature-displacement coupling. Regarding the influence of temperature, the Arrhenius equation is adopted for the time-temperature relationship. The activation energy value that is required for the simulation is firstly determined from shifting the experimental CS results with the time-temperature superposition technique and plotting the shift factors in an Arrhenius diagram. The experiments were compared with the simulation results. Afterwards different activation energies were used in the simulation and discussed. A suitable choice of the activation energy value with regard to the reference temperature and the test temperature is presented. With the chosen activation energies, the match between numerical CS values after long-term aging and the experimental results was improved. T2 - ASME 2022 Pressure Vessels & Piping Conference CY - Las Vegas, USA DA - 17.07.2022 KW - Simulation KW - Compression set KW - EPDM KW - Aging PY - 2022 SP - 1 EP - 9 AN - OPUS4-57370 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - VIDEO A1 - Pauw, Brian Richard T1 - "Ultima Ratio": Multi-scale, high-resolution 3D-FFT scattering pattern simulations N2 - This talk highlights a proof-of-concept that demonstrates the ability to calculate high-resolution Fourier transforms. These can be combined with multi-scale modeling to simulate scattering over a wide range, from small-angle scattering to XRD and PDF. The preprint documenting this is available on the ArXiv here: https://doi.org/10.48550/arXiv.2303.13435 The Jupyter notebook, VASP calculation details and MOUSE measured scattering patterns are available from this Zenodo repository: https://dx.doi.org/10.5281/zenodo.7764045 T2 - Shapespyer/MuSSIC Launch Workshop CY - Didcot, UK DA - 20.02.2023 KW - Video KW - Simulation KW - High-resolution KW - Fourier Transform KW - 3D FFT KW - Nanomaterial KW - Metal organic framework KW - MOF KW - SAXS KW - XRD KW - PDF KW - X-ray diffraction KW - Pair distribution function KW - Small-angle X-ray scattering PY - 2023 UR - https://www.youtube.com/watch?v=lEApkOqR5e8 DO - https://doi.org/10.26272/opus4-57212 PB - YouTube, LLC CY - San Bruno, CA, USA AN - OPUS4-57212 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Ballach, F. A1 - Bartscher, M. A1 - Bellon, Carsten A1 - Borges de Oliveira, F. A1 - Braun, M. A1 - Dennerlein, F. A1 - Flessner, M. A1 - Fuchs, P. A1 - Günnewig, O. A1 - Hausotte, T. A1 - Hess, J. A1 - Kasperl, S. A1 - Kirschbaum, K. A1 - Li, K. A1 - Maass, N. A1 - Mayer, T. A1 - Orth, Anthony A1 - Reuter, T. A1 - Suppes, A. A1 - von Schmid, M. A1 - Weiß, D. T1 - Realistische Simulation realer Röntgencomputertomografie-Systeme mit basisqualifizierter Simulationssoftware – CTSimU2 BT - Abschlussbericht N2 - Das Förderprojekt CTSimU2 baute auf den Ergebnissen des Projektes CTSimU auf. Dieses Vorprojekt erarbeitete ein (Basis-)Qualifizierungsframework für Simulationssoftwares zur Anwendung bei der Röntgen-CT für dimensionelle Messungen. Dabei stand die ausreichende physikalische Korrektheit der Durchstrahlungssimulation im Vordergrund. Für die realitätsnahe Simulation einer CT-Anlage in einer Simulationssoftware (Digitales Modell) ist jedoch nicht nur die Korrektheit der Simulationssoftware selbst, sondern auch die Güte der Parametrisierung des realen CT-Systems in der Simulationssoftware entscheidend – dies stellte den Ausgangspunkt dar. Die Parametrisierung eines CT-Systems in einer Simulationssoftware lässt sich in vier Schritte unterteilen: nach der Datenaufnahme am realen CT-System folgt die Auswertung der aufgenommenen Daten für die Generierung allgemeiner Parameterangaben. Als letztes folgte die Übertragung der Parameter in die spezifischen Simulationssoftwares und die Validierung der resultierenden Simulationsparameter. Die Methodik der Datenaufnahme am CT und die Auswertung der Daten wurde in einem Werkzeugkasten allgemein beschrieben. Der dritte Schritt, die Umsetzung der Parameter, war softwarespezifisch und wurde beispielhaft mit den vorhandenen Simulationssoftwares durchgeführt. Die Validierung der Parameter war standardisierbar und konnte durch den entwickelten Test geleistet werden, auf dessen Basis die ausreichend korrekte Simulation einer realen Anlage beurteilt werden konnte. Endresultat des Projektes war ein Richtlinienentwurf (z. B. VDI/VDE 2630) zu diesem Test, der einen informativen Annex zum Stand der Technik bezüglich der Möglichkeiten zur Parameterbestimmung enthält. Mit einer Simulationssoftware, die die Basisqualifizierung aus CTSimU bestanden hat und einen Parameterdatensatz für ein reales CT-System enthält, der den Test aus CTSimU2 bestanden hat, können realistische Simulationen dieses CT-Systems möglich sein. KW - Computertomografie KW - Simulation KW - Dimensionelles Messen PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641719 DO - https://doi.org/10.34657/21602 N1 - Dieses Projekt wurde durch die Förderrichtlinie WIPANO gefördert und durch das Bundesministerium für Wirtschaft und Klimaschutz (2022 -2025) finanziert. Der Projektträger Jülich verwaltet die Projekte der Förderrichtlinie WIPANO. SP - 1 EP - 22 PB - TIB Technische Informationsbibliothek CY - Hannover AN - OPUS4-64171 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geoerg, Paul A1 - Hofmann-Böllinghaus, Anja A1 - Pulm, A. T1 - Evacuation dynamics under consideration of vulnerable pedestrian groups N2 - The understanding of human behavior during evacuation processes is an important matter to improve the safety of infrastructures. In many countries, the implementation of performance based codes enables fire safety engineers to use computer based calculation tools to predict and evaluate pedestrian movement and human behavior in buildings. The models are based on experimentally obtained parameters and theoretical models. Pedestrian behavior can be influenced by the characteristics of the buildings (e.g. type of the building) as well as the characteristics of individuals and the pedestrian group. This paper shows that the approach of Required Safe Egress Time (RSET) / Available Safe Egress Time (ASET) is imprecise with regard on heterogeneous pedestrian groups, because this concept completely neglected the variability’s in individual pre-movement and movement abilities. T2 - Interflam CY - Royal Holloway College, London, UK DA - 04.07.2016 KW - Evacuation KW - Vulnerable groups KW - Simulation KW - Egress PY - 2016 SN - 978-0-9933933-1-0 SN - 978-0-9933933-3-4 VL - 1 SP - 769 EP - 774 CY - London, UK AN - OPUS4-36821 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Vöse, Markus A1 - Fedelich, Bernard ED - Maruyama, K. ED - Abe, F. ED - Igarashi, M. ED - Kishida, K. ED - Suzuki, M. ED - Yoshimi, K. T1 - Grain boundary cavitation under time-varying normal stresses N2 - In a polycrystal, the development of creep damage, especially for low extemal loads, is related to nucleation and difiüsive growth of cavities on the grain boundaries. For low stresses, the contribution to cavity growth by dislocation creep of the suirounding material can be neglected. However, grain boundaiy diffitsion is mainly driven by the local normal stiess acting on the grain boundaiy. Under creep conditions, even under a constant extemal load, an individual grain boundaiy generally experiences a time-varying normal stress, due to stress redistributions within the polycrystalline stiuctuie. Indeed, a constrained cavitating grain boundaiy is relieved, since matter is transported to and deposited in the grain boundaiy plane, which causes the adjoining giains to drill apart. A Simulation proceduie based on the use of complex holomoiphic fiinctions for solving the diffiision problem has been used to investigate multiple cavity growth on a grain boundaiy subjected to a constant normal stress. A simplified model has been developed to describe the cavitation behaviour observed in the simulations. Finally, the analysis of cavitation simulations with time-vaiying nomial stresses, including the cases with veiy low or negative stresses, has been used to extend the simplified cavitation model to more general normal stiess time profiles. T2 - 12th International Conference on Creep and Fracture of Engineering Materials and Structures CY - Kyoto, Japan DA - 27.05.2012 KW - Creep damage KW - Grain boundary diffusion KW - Cavitation KW - Simulation KW - Evolution equations PY - 2012 SP - 1 EP - 4 AN - OPUS4-27544 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Pauw, Brian Richard A1 - Laskina, Sofya A1 - Naik, Aakash A1 - Smales, Glen Jacob A1 - George, Janine A1 - Breßler, Ingo A1 - Benner, Philipp T1 - "Ultima Ratio": Simulating wide-range X-ray scattering and diffraction N2 - We demonstrate a strategy for simulating wide-range X-ray scattering patterns, which spans the small- and wide scattering angles as well as the scattering angles typically used for Pair Distribution Function (PDF) analysis. Such simulated patterns can be used to test holistic analysis models, and, since the diffraction intensity is on the same scale as the scattering intensity, may offer a novel pathway for determining the degree of crystallinity. The "Ultima Ratio" strategy is demonstrated on a 64-nm Metal Organic Framework (MOF) particle, calculated from Q < 0.01 1/nm up to Q < 150 1/nm, with a resolution of 0.16 Angstrom. The computations exploit a modified 3D Fast Fourier Transform (3D-FFT), whose modifications enable the transformations of matrices at least up to 8000^3 voxels in size. Multiple of these modified 3D-FFTs are combined to improve the low-Q behaviour. The resulting curve is compared to a wide-range scattering pattern measured on a polydisperse MOF powder. While computationally intensive, the approach is expected to be useful for simulating scattering from a wide range of realistic, complex structures, from (poly-)crystalline particles to hierarchical, multicomponent structures such as viruses and catalysts. KW - X-ray KW - Simulation KW - 3D Fourier Transform KW - High resolution KW - XRD KW - SAXS KW - PDF KW - Total scattering KW - X-ray scattering KW - Metal organic framework KW - Electron density map KW - FFT PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572067 DO - https://doi.org/10.48550/arXiv.2303.13435 VL - Cornell University SP - 1 EP - 12 PB - Ithaca, NY AN - OPUS4-57206 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Pauw, Brian Richard A1 - Laskina, Sofya A1 - Naik, Aakash A1 - Smales, Glen Jacob A1 - George, Janine A1 - Breßler, Ingo A1 - Benner, Philipp T1 - Jupyter notebook and VASP calculation details accompanying the manuscript: "Ultima Ratio: Simulating wide-range X-ray scattering and diffraction" N2 - Summary: This notebook and associated datasets (including VASP details) accompany a manuscript available on the ArXiv (https://doi.org/10.48550/arXiv.2303.13435) and hopefully soon in a journal as short communication as well. Most of the details needed to understand this notebook are explained in that paper with the same title as above. For convenience, the abstract is repeated here: Paper abstract: We demonstrate a strategy for simulating wide-range X-ray scattering patterns, which spans the small- and wide scattering angles as well as the scattering angles typically used for Pair Distribution Function (PDF) analysis. Such simulated patterns can be used to test holistic analysis models, and, since the diffraction intensity is presented coupled to the scattering intensity, may offer a novel pathway for determining the degree of crystallinity. The "Ultima Ratio" strategy is demonstrated on a 64-nm Metal Organic Framework (MOF) particle, calculated from $Q<0.01$\,$\mathrm{nm}^{-1}$ up to $Q\approx150$\,$\mathrm{nm}^{-1}$, with a resolution of 0.16\,\AA. The computations exploit a modified 3D Fast Fourier Transform (3D-FFT), whose modifications enable the transformations of matrices at least up to $8000^3$ voxels in size. Multiple of these modified 3D-FFTs are combined to improve the low-$Q$ behaviour. The resulting curve is compared to a wide-range scattering pattern measured on a polydisperse MOF powder. While computationally intensive, the approach is expected to be useful for simulating scattering from a wide range of realistic, complex structures, from (poly-)crystalline particles to hierarchical, multicomponent structures such as viruses and catalysts. KW - X-ray KW - Simulation KW - Scattering KW - MOUSE KW - Nanomaterials KW - XRD KW - SAXS KW - PDF KW - Total scattering KW - 3D Fourier transform KW - High resolution KW - FFT PY - 2023 DO - https://doi.org/10.5281/zenodo.7764044 PB - Zenodo CY - Geneva AN - OPUS4-57207 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -