TY - JOUR A1 - Janczynski, Jessica A1 - Tewes, Andreas A1 - Ulbricht, Alexander A1 - Jaenisch, Gerd-Rüdiger T1 - Evaluation Metrics for Comparison between Virtual and Industrial XCT N2 - Simulations of XCT systems, as employed in the context of the manufacturing and design process, represent a time-saving, cost- and resource-efficient alternative to repeated experimental measurements. This article is dedicated to the development and evaluation of various metrics that should enable an adequate verification and optimization of a XCT simulation of an experimental XCT system. The present study employed statistical evaluation as a methodological approach. The present article makes a significant contribution to the optimization of the development process of a XCT simulation and provides a foundation for future research activities in this field. KW - Computed Tomography KW - Computertomographie KW - aRTist KW - Simulation KW - Virtual CT KW - Evaluation PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641444 DO - https://doi.org/10.1007/s10921-025-01213-w SN - 0195-9298 VL - 44 IS - 4 SP - 1 EP - 11 PB - Springer Science and Business Media LLC CY - Berlin/Heidelberg AN - OPUS4-64144 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nandish, Ranjith A1 - Knaust, Christian A1 - Hofmann-Böllinghaus, Anja A1 - Gnutzmann, Tanja A1 - Zehfuß, Jochen T1 - Simulation of wood pyrolysis with component-based mechanism N2 - This paper presents a comprehensive fire simulation study that models the pyrolysis process of beech wood using kinetic parameters with the Fire Dynamics Simulator (FDS). The kinetic methodology is based on the application of these kinetic parameters to govern the underlying pyrolysis reactions. The primary objective was to numerically model the pyrolysis process for beech wood using both single-component (single-step, single reaction scheme) and multi-component (single-step, multi-reaction scheme) kinetic reaction schemes. The accuracy of the numerical model was validated by comparing FDS simulation results with experimental data obtained from thermogravimetric analysis (TGA) and cone calorimeter tests. This approach aids in identifying reliable kinetic reaction input parameters for modelling wood fires. A case study was included to demonstrate the implementation of the kinetic reaction schemes. Numerical results from the TGA simulations for the small-scale pure cellulose test using the single-component approach exhibit consistency with the experimental data. Furthermore, the results demonstrated that the multi-component approach more accurately replicates the shape of the experimental curve for beech wood compared to the single-component approach. However, discrepancies in the tail regions of the curves obtained from the FDS simulations showed the need for further improvement in the modelling approach, particularly regarding the exclusion of char oxidation reactions, which needs to be investigated further. KW - Simulation KW - Wood PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639272 DO - https://doi.org/10.1007/s00231-025-03571-7 SN - 0947-7411 VL - 61 IS - 6 SP - 1 EP - 14 PB - Springer Science and Business Media LLC AN - OPUS4-63927 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Biegler, Max A1 - Yang, Keke A1 - Meschut, Gerson A1 - Rethmeier, Michael T1 - Occurrence and avoidance of liquid metal embrittlement in resistance spot welding of springback-afflicted deep-drawn components N2 - This study investigates the occurrence and mitigation of liquid metal embrittlement occurring during resistance spot welding in deep-drawn automotive components, specifically focusing on an S-Rail made from advanced high-strength steel. A simulation-based liquid metal embrittlement risk criterion based on local major component stresses was established and used to quantify and compare liquid metal embrittlement risks between different tests. Experimental and numerical analyses were conducted, revealing that springback significantly impacts liquid metal embrittlement formation. Adjustments in electrode geometry and hold time post-welding were found to mitigate liquid metal embrittlement risks. The effects of stack-up configuration and related parameter settings on liquid metal embrittlement occurrence were identified and liquid metal embrittlement was effectively prevented across both stack-up configurations. These findings advance the understanding of liquid metal embrittlement mechanisms and provide practical approaches to enhance the spot weld quality in AHSS-based body-in-whites. KW - Liquid metal embrittlement KW - Crack KW - Advanced high-strength steels KW - Resistance spot welding KW - Weld current KW - Heat input KW - Simulation KW - Springback KW - Deep drawing KW - S-Rail PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636577 DO - https://doi.org/10.1177/13621718251340452 SN - 1362-1718 SP - 1 EP - 9 PB - SAGE Publications AN - OPUS4-63657 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Willms, Thomas A1 - Kryk, Holger A1 - Hampel, Uwe T1 - An improved method for the analysis of the reaction products of the partial isobutane oxidation by gas chromatography using a green solvent N2 - In the present work, an improved GC/MS method for the analysis of the reaction products of the non-catalytic partial oxidation of isobutane at a starting temperature of 25°C has been developed and compared to a previously published method. Two green GC-solvents (dimethyl carbonate (DMC), diethyl carbonate (DEC)) and several internal standards (hexane, benzene, toluene, DEC) have been tested. The separation of the products at low retention times (methanol, isobutane, isobutene) could be significantly improved. For the liquid main products t-butyl hydroperoxide (TBHP), di-t-butyl peroxide (DTBP), t-butanol (TBA), propanone and most trace products (isopropanol, isobutanal, methyl formate, isopropyl formate, t-butyl formate and some acetates – 24 compounds in total), a coefficient of determination CoD > 0.999 has been achieved. For all weighing and GC/MS measurements uncertainties have been calculated. The peaks of the peak pair t-butyl formate (CoD >0.999) and isobutanol (CoD >0.99), have been simulated and used for calibrations. DEC gave a decomposition of TBHP on the column. With DMC, a problem of peak purity of TBHP appeared but could be resolved. The use of the green solvent DMC, compared to also studied traditional solvents like heptane and toluene, proved to be very beneficial, since it also permitted to determine polar compounds, e. g. carbon dioxide and formic acid. KW - GC/MS KW - Green solvent KW - Method development KW - Peroxide KW - Measurement uncertainties KW - Oxidation products KW - Simulation PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632026 DO - https://doi.org/10.1016/j.chroma.2025.465892 SN - 0021-9673 VL - 1753 SP - 1 EP - 16 PB - Elsevier CY - Amsterdam AN - OPUS4-63202 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seitz, Georg A1 - Bantle, Patrick A1 - Biegler, Max A1 - Elsner, Beatrix A. M. A1 - Rethmeier, Michael T1 - An Inherent Strain Method Using Progressive Element Activation for Fast Distortion Calculation in Directed Energy Deposition N2 - The finite element analysis (FEA) simulation of directed energy deposition (DED) processes offers many potential cost savings during the build job optimization process, through, e.g., distortion predictions. However, the biggest challenge is the long calculation time, frequently exceeding the actual build time. One way of simplifying the simulation with the aim of reducing the calculation times is the inherent strain method. While this method is already used commercially in the simulation of powder bed-based processes and conventional welding technologies, its use in DED is still the subject of research. In this work, an inverse determination of an inherent strain is carried out on a 20-layer-high, single-track-wide wall, common theories are reviewed, and an approach based on thermal strain is introduced. As a result, the calculation time could be reduced by 83% and the accuracy remained at 92%. KW - Inherent strain method KW - Simulation KW - Finite element analysis KW - Directed energy deposition KW - Additive manufacturing PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622595 DO - https://doi.org/10.3390/met14121338 SN - 2075-4701 VL - 14 IS - 12 SP - 1 EP - 12 PB - MDPI AN - OPUS4-62259 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Deumer, J. A1 - Andresen, Elina A1 - Gollwitzer, C. A1 - Schürmann, R. A1 - Resch-Genger, Ute T1 - Adding More Shape to Nanoscale Reference Materials-LiYF4:Yb,Tm Bipyramids as Standards for Sizing Methods and Particle Number Concentration N2 - The increasing industrial use of nanomaterials calls for the reliable characterization of their physicochemical key properties like size, size distribution, shape, and surface chemistry, and test and reference materials (RMs) with sizes and shapes, closely matching real-world nonspheric nano-objects. An efficient strategy to minimize efforts in producing nanoscale RMs (nanoRMs) for establishing, validating, and standardizing methods for characterizing nanomaterials are multimethod nanoRMs. Ideal candidates are lanthanide-based, multicolor luminescent, and chemically inert nanoparticles (NPs) like upconversion nanoparticles (UCNPs), which can be prepared in different sizes, shapes, and chemical composition with various surface coatings. This makes UCNPs interesting candidates as standards not only for sizing methods, but also for element-analytical methods like laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), quantitative bioimaging methods like X-ray fluorescence computed tomography (XFCT), and luminescence methods and correlative measurements. Here, we explore the potential of two monodisperse LiYF4:Yb,Tm bipyramids with peak-to-peak distances of (43 ± 2) nm and (29 ± 2) nm as size standards for small-angle X-ray scattering (SAXS) and tools for establishing and validating the sophisticated simulations required for the analysis of SAXS data derived from dispersions of nonspheric nano-objects. These SAXS studies are supplemented by two-dimensional (2D)-transmission electron microscopy measurements of the UCNP bipyramids. Additionally, the particle number concentration of cyclohexane dispersions of these UCNP bipyramids is determined by absolute SAXS measurements, complemented by gravimetry, thermogravimetric analysis (TGA), and inductively coupled plasma optical emission spectrometry (ICP-OES). This approach enables traceable particle number concentration measurements of ligand-capped nonspheric particles with unknown chemical composition. KW - Fluorescence KW - Upconversion nanoparticles KW - SAXS KW - Particle number concentration KW - Reference material KW - Traceability KW - Quality assurance KW - Quantum yield KW - Spectroscopy KW - Synthesis KW - Quantification KW - NanoRM KW - Nano KW - Particle KW - Bipyramid KW - Reference data KW - Simulation PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617940 DO - https://doi.org/10.1021/acs.analchem.4c03641 SP - 1 EP - 8 PB - ACS Publications AN - OPUS4-61794 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wu, Hongyi A1 - Hofmann-Böllinghaus, Anja ED - Makovická Osvaldová, L. ED - Hasburgh, L. E. ED - Das, O. T1 - Applying experimental determined kinetic parameters to the simulation of vegetation fire in the Fire Dynamics Simulator N2 - Although intense wildfire research has been done in the US and in Australia, it cannot be transferred directly to the situation in Europe as the local vegetation has a significant influence on the fire spread. The EU-funded project TREEADS and the so-called German pilot within the project are concentrating on wildfire in Europe. Extensive experimental research is done on local vegeta-tion in Germany and the experimental results are used to adjust the Fire Dynam-ics Simulator (FDS) to local vegetation as a fuel in the calculations. The particle model and the boundary fuel model are developed for the simulation of forest fires. Both models require the kinetic input for the dehydration, pyrolysis, and char oxidation process. This three-step simplified model describes the basic fuel combustion kinetic. Most published simulations use the default kinetic input of pine needles from FDS user manual. To adjust the simulation to local vegetation, the corresponding kinetic parame-ters have been experimental investigated. Samples of pine needles, moss and other falling leaves were collected, air dried and grinded into powder. The TG analysis of all these samples were done under different heating rate of 5, 10 and 20K/min. The activation energy and the corresponding pre-exponential factor were calcu-lated. The results show that fire spread depends significantly on the vegetation and comparison with small scale experiments show good agreement using the new kinetic parameters. The new model is applied to a larger scenario and will be compared to the results of large-scale experiments for further validation of the model. T2 - Wood and Fire Safety 2024 CY - Štrbské Pleso, Slovakia DA - 12.05.2024 KW - Forest KW - Simulation KW - FDS KW - Vegetation fire KW - Fire Dynamics Simulator KW - Kinetic parameters PY - 2024 SN - 978-3-031-59177-8 DO - https://doi.org/10.1007/978-3-031-59177-8_45 SP - 389 EP - 396 PB - Springer CY - Cham AN - OPUS4-60252 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Turski Silva Diniz, Analice A1 - Schartel, Bernhard T1 - The effects of property variation on the dripping behaviour of polymers during UL94 test simulated by particle finite element method N2 - The dripping behaviour of polymers is often observed experimentally through the UL94 flammability standard test. In this work, polymeric dripping under fire is investigated numerically using particle finite element method. A parametric analysis was carried out to observe the influence of a single property on overall dripping behaviour via a UL94 vertical test model. Surrogates and property ranges were defined for variation of the following parameters: glass transition temperature (Tg), melting temperature (Tm), decomposition temperature (Td), density (ρ), specific heat capacity (Cp), apparent effective heat of combustion of the volatiles, char yield (μ), thermal conductivity (k), and viscosity (η). Polyamide, poly(ether ether ketone), poly(methyl methacrylate), and polysulfone were used as benchmarks. Simulated results showed that specific heat capacity, thermal conductivity, and char yield allied with viscosity were the properties that most influenced dripping behaviour (starting time and occurrence). KW - Dripping KW - PFEM KW - UL 94 KW - Simulation KW - Fire behaviour PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597449 DO - https://doi.org/10.1515/epoly-2023-0194 SN - 1618-7229 VL - 24 IS - 1 PB - De Gruyter AN - OPUS4-59744 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Drendel, Jan A1 - Logvinov, Ruslan A1 - Heinrichsdorff, Frank A1 - Hilgenberg, Kai T1 - Simulation-based controlling of local surface temperature in laser powder bed fusion using the process laser N2 - State-of-the-art laser powder bed fusion (PBF-LB/M) machines allow pre-heating of the substrate plate to reduce stress and improve part quality. However, two major issues have been shown in the past: First, with increasing build height the apparent pre-heat temperature at the surface can deviate drastically from the nominal pre-heat temperature in the substrate plate. Second, even within a single layer the local surface pre-heat temperature can show large gradients due to thermal bottlenecks in the part geometry underneath the top surface. Both lead to unwanted changes in microstructure or defects in the final parts. In this study, a first attempt is taken to show the feasibility of pre-heating the top surface with the onboard laser beam to overcome the mentioned issues. A single layer of a group of three parts built from IN718 to a height of 33.5 mm is pre-heated in a commercially available PBF-LB/M machine to an average steady state surface temperature of 200 °C using the onboard laser beam. The parts are continuously heated, omitting powder deposition and melting step. Temperatures are measured by thermocouples underneath the surface. The experiments are supported by a thermal finite element (FE) model that predicts the temperature field in the parts. When heating the parts uniformly with the laser beam, differences in surface temperatures as large as 170 K are observed. To overcome this inhomogeneity, the heat flux supplied by the laser beam is modulated. An optimized, spatial heat flow distribution is provided by the thermal FE model and translated into a scan pattern that reproduces the optimized heat distribution on the PBF-LB/M machine by locally modulating hatch distance and scan velocity. This successfully reduces the differences in surface temperature to 20 K. Thermographic imaging shows that a homogeneous surface temperature can be achieved despite the localized heat input by the beam. The potential for industrial application of the optimized laser-heating technique is discussed. KW - Additive Manufacturing KW - Simulation KW - Surface temperature KW - Laser powder bed fusion PY - 2023 DO - https://doi.org/10.1016/j.addma.2023.103854 SN - 2214-8604 VL - 78 SP - 1 EP - 16 PB - Elsevier B.V. AN - OPUS4-58825 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yang, K. A1 - Meschut, G. A1 - Seitz, G. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - The Identification of a New Liquid Metal Embrittlement (LME) Type in Resistance Spot Welding of Advanced High Strength Steels on Reduced Flange Widths N2 - Liquid metal embrittlement (LME) cracking is a phenomenon observed during resistance spot welding (RSW) of zinc􀀀coated advanced high􀀀strength steels (AHSS) in automotive manufacturing. In this study, severe cracks are observed at the edge of the sheet under reduced flange widths. These cracks, traversing the AHSS sheet, culminate at the edge with a width of approximately 1.2 mm. Through combined numerical and experimental investigations, and material testing, these cracks are identified and validated as a new type of LME crack. The mechanism behind this crack formation is attributed to unique geometric conditions that, when compared to center welding, amplify radial material flow by ninefold to 0.87 mm. The resultant tangential tensile stresses approximate 760 MPa, which exceed the yield strength of the examined advanced high􀀀strength steel (AHSS) under heightened temperature conditions, and when combined with liquid zinc, promote the formation of this new type of LME crack. KW - Liquid metal embrittlement KW - Crack KW - Advanced high strength steels KW - Resistance spot welding KW - Simulation KW - Flange width PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586940 DO - https://doi.org/10.3390/met13101754 VL - 13 IS - 10 SP - 1 EP - 13 PB - MDPI AN - OPUS4-58694 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Borges de Oliveira, F. A1 - Reuter, T. A1 - Plotzki, David A1 - Wohlgemuth, F. A1 - Bartscher, M. A1 - Bellon, Carsten A1 - Kasperl, S. T1 - Assessment of 2D-based tests for the qualification of simulation software for dXCT N2 - The interest in using computer simulations of dimensional x-ray computed tomography (dXCT) for various metrological purposes—such as measurement planning, performance prediction, performance optimisation and, finally, measurement uncertainty estimation—is increasing along with the ever-growing demand for more reliable measurements with dXCT. However, before a piece of simulation software can be used for tasks related to coordinate metrology, it has to be ensured that it is able to simulate physical laws, characteristic effects and basic CT system functionalities correctly and with sufficient accuracy. In short, the software must be qualified for dimensional metrology tasks. As one part of such a qualification process, a method is presented here for determining conformity intervals of 2D tests (projection-based tests) based on 3D tests (testing based on dimensional evaluations in a reconstructed volume) for the assessment of dXCT simulation software. The method consists of varying relevant parameter values in order to verify their influence on 3D measurement results. The results of the 3D tests with varied parameter values are then transferred to the quantities tested in the 2D tests and used as the basis for determining conformity intervals. Two approaches are applied for determining whether or not a variation of a parameter value is significant: (a) statistical and (b) heuristic. Two examples are presented, each based on simulated images, which show the application of the two different approaches for determining conformity intervals for the results of the 2D tests. KW - dXCT KW - X-ray computed tomography KW - Simulation PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573316 DO - https://doi.org/10.1088/1361-6501/acc1f9 VL - 34 IS - 6 SP - 1 EP - 12 PB - IOP Publishing AN - OPUS4-57331 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, Marc Benjamin T1 - Accessing radiation damage to biomolecules on the nanoscale by particle-scattering simulations N2 - Radiation damage to DNA plays a central role in radiation therapy to cure cancer. The physico-chemical and biological processes involved encompass huge time and spatial scales. To obtain a comprehensive understanding on the nano and the macro scale is a very challenging tasks for experimental techniques alone. Therefore particle-scattering simulations are often applied to complement measurements and aide their interpretation, to help in the planning of experiments, to predict their outcome and to test damage models. In the last years, powerful multipurpose particle-scattering framework based on the Monte-Carlo simulation (MCS) method, such as Geant4 and Geant4-DNA, were extended by user friendly interfaces such as TOPAS and TOPAS-nBio. This shifts their applicability from the realm of dedicated specialists to a broader range of scientists. In the present review we aim to give an overview over MCS based approaches to understand radiation interaction on a broad scale, ranging from cancerous tissue, cells and their organelles including the nucleus, mitochondria and membranes, over radiosensitizer such as metallic nanoparticles, and water with additional radical scavenger, down to isolated biomolecules in the form of DNA, RNA, proteins and DNA-protein complexes. Hereby the degradation of biomolecules by direct damage from inelastic scattering processes during the physical stage, and the indirect damage caused by radicals during the chemical stage as well as some parts of the early biological response is covered. Due to their high abundance the action of hydroxyl radicals (•OH) and secondary low energy electrons (LEE) as well as prehydrated electrons are covered in additional detail. Applications in the prediction of DNA damage, DNA repair processes, cell survival and apoptosis, influence of radiosensitizer on the dose distribution within cells and their organelles, the study of linear energy transfer (LET), the relative biological effectiveness (RBE), ion beam cancer therapy, microbeam radiation therapy (MRT), the FLASH effect, and the radiation induced bystander effect are reviewed. KW - DNA KW - Protein KW - G5P KW - OH KW - Au KW - AuNP KW - Radiation KW - SSB KW - DSB KW - Beta decay KW - Brachytherapy KW - Cancer treatment KW - Clustered nanoparticles KW - DNA damage KW - Dosimetry KW - Energy deposit KW - Geant4 KW - Geant4-DNA KW - Gold Nanoparticles KW - Livermore model KW - Low energy electrons KW - MCS KW - Microdosimetry KW - Monte-Carlo simulation KW - NP KW - OH radical KW - Particle scattering KW - Penelope model KW - Proteins KW - Radiation damage KW - Radiation therapy KW - Radiationtherapy KW - Radioactive decay KW - Radiolysis KW - Radiotherapy KW - Simulation KW - TOPAS KW - TOPAS-nbio KW - Base damage KW - Base loss KW - DNA radiation damage KW - Direct damage KW - Dissociative electron attachment (DEA) KW - Dissociative electron transfer (DET) KW - Double-strand break (DSB) KW - ESCA KW - Hydrated DNA KW - Hydrated electron KW - Hydration shell KW - Hydroxyl radical KW - Indirect damage KW - Ionization KW - Ionisation KW - NAP-XPS KW - Near ambient pressure xray photo electron spectroscopy KW - Net-ionization reaction KW - Prehydrated electron KW - Presolvated electron KW - Quasi-direct damage KW - ROS KW - Radical KW - Reactive oxygen species KW - Single-strand break (SSB) KW - XPS KW - Xray KW - Xray photo electron spectrocopy KW - Cosolute KW - Ectoin KW - Ectoine KW - GVP KW - Gene five protein KW - Hydroxyectoine KW - Ionizing radiation damage KW - OH radical scavenger KW - Monte-Carlo simulations KW - Nanodosimetry KW - Osmolyte KW - Particle scattering simulations KW - Protein unfolding KW - Radical Scavenge KW - Radical scavenger KW - Single-stranded DNA-binding proteins KW - SAXS KW - Bio-SAXS KW - X-ray scattering KW - ssDNA KW - dsDNA KW - FLASH effect KW - Bystander effect KW - Ion beam therapy KW - Bragg peak KW - LET KW - MCNP KW - Photons KW - Electrons KW - Carbon ions KW - MRT KW - RNA KW - RBE KW - base loss KW - abasic side KW - DMSO KW - Cells PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573240 DO - https://doi.org/10.1088/2399-6528/accb3f SN - 2399-6528 VL - 7 IS - 4 SP - 042001 PB - Institute of Physics (IOP) Publishing CY - London AN - OPUS4-57324 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Herr, M. A1 - Borras, F. X. A1 - Spaltmann, Dirk A1 - Kröll, Mirco A1 - Pirker, F. A1 - Cihak-Bayr, U. T1 - How to create trusted tribological characterization data of soft polymers as input for FEM simulations? N2 - Soft polymers such as the investigated polyurethane, characterized by low Young’s moduli and prone to high shear deflection, are frequently applied in pneumatic cylinders. Their performance and lifetime without external lubrication are highly determined by the friction between seal and shaft and the wear rate. FEM simulation has established itself as a tool in seal design processes but requires input values for friction and wear depending on material, load, and velocity. This paper presents a tribological test configuration for long stroke, reciprocating movement, allowing the generation of data which meet the requirements of input parameters for FEM simulations without the geometrical influences of specific seal profiles. A numerical parameter study, performed with an FEM model, revealed the most eligible sample geometry as a flat, disc-shaped sample of the polymer glued on a stiff sample holder. At the same time, the study illustrates that the sensitivity of the contact pressure distribution to Poisson’s ratio and CoF can be minimized by the developed and verified setup. It ensures robust, reliable, and repeatable experimental results with uniform contact pressures and constant contact areas to be used in databases and FEM simulations of seals, enabling upscaling from generically shaped samples to complex seal profiles. KW - Tribologie KW - FEM KW - Simulation KW - Polymere KW - Charakterisierung KW - i-TRIBOMAT KW - Modellierung KW - Polyurethan KW - Dichtungen KW - Upscaling PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567683 DO - https://doi.org/10.3390/ma16010131 SN - 1996-1944 VL - 16 IS - 1 SP - 1 EP - 20 PB - MDPI CY - Basel AN - OPUS4-56768 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Deumer, J. A1 - Pauw, Brian Richard A1 - Marguet, S. A1 - Skroblin, D. A1 - Taché, O. A1 - Krumrey, M. A1 - Gollwitzer, C. T1 - Small-angle X-ray scattering: characterization of cubic Au nanoparticles using Debye’s scattering formula N2 - A versatile software package in the form of a Python extension, named CDEF (computing Debye’s scattering formula for extraordinary form factors), is proposed to calculate approximate scattering profiles of arbitrarily shaped nanoparticles for small-angle X-ray scattering (SAXS). CDEF generates a quasi-randomly distributed point cloud in the desired particle shape and then applies the open-source software DEBYER for efficient evaluation of Debye’s scattering formula to calculate the SAXS pattern (https://github.com/j-from-b/CDEF). If self-correlation of the scattering signal is not omitted, the quasi-random distribution provides faster convergence compared with a true-random distribution of the scatterers, especially at higher momentum transfer. The usage of the software is demonstrated for the evaluation of scattering data of Au nanocubes with rounded edges, which were measured at the four-crystal monochromator beamline of PTB at the synchrotron radiation facility BESSY II in Berlin. The implementation is fast enough to run on a single desktop computer and perform model fits within minutes. The accuracy of the method was analyzed by comparison with analytically known form factors and verified with another implementation, the SPONGE, based on a similar principle with fewer approximations. Additionally, the SPONGE coupled to McSAS3 allows one to retrieve information on the uncertainty of the size distribution using a Monte Carlo uncertainty estimation algorithm. KW - X-ray scattering KW - SAXS KW - Non-spherical nanoparticles KW - Nanoparticles KW - Nanomaterials KW - Debye scattering equation KW - Simulation KW - Data fitting PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557652 DO - https://doi.org/10.1107/S160057672200499X VL - 55 IS - Pt 4 SP - 993 EP - 1001 PB - International Union of Crystallography CY - Chester, England AN - OPUS4-55765 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reuter, T. A1 - Plotzki, David A1 - Borges de Oliveira, F. A1 - Wohlgemuth, F. A1 - Bauer, F. A1 - Ballach, F. A1 - Kimmig, W. A1 - Wagner, G. A1 - Watzl, C. A1 - Weiß, D. A1 - Hausotte, T. T1 - Numerical measurement uncertainty evaluation for X-ray computed tomography using simulations – A first approach to build a digital twin N2 - The ability of industrial X-ray computed tomography (CT) to scan an object with several internal and external features at once causes increasing adoption in dimensional metrology. In order to evaluate the quality of a measurement value, the task-specific measurement uncertainty has to be determined. Currently, VDI/VDE 2630 part 2.1 gives a guideline to determine the uncertainty of CT measurements experimentally by conducting repeated measurements. This is costly and time-consuming. Thus, the aim is to determine the task-specific measurement uncertainty numerically by simulations (e. g. according to the guide to expression of uncertainty in measurement (GUM) Supplement 1). To achieve that, a digital twin is necessary. This contribution presents a simple first approach how a digital twin can be built. In order to evaluate this approach, a study comparing measurements and simulations of different real CT systems was carried out by determining the differences between the measurement results of the digital twin and of the measurement results of the real-world CT systems. The results have shown a moderate agreement between real and simulated data. To improve on this aspect, a standardized method to characterize CT systems and methods to implement CT parameters into the simulation with sufficient accuracy will be developed. N2 - Die industrielle Röntgencomputertomografie (CT) wird durch ihre Fähigkeit, ein Messobjekt mit unterschiedlichen inneren und äußeren Merkmalen auf einmal zu messen, immer häufiger auch in der dimensionellen Messtechnik eingesetzt. Um die Güte eines Messwertes beurteilen zu können, muss die aufgabenspezifische Messunsicherheit ermittelt werden. Mit der Richtlinie VDI/VDE 2630 Blatt 2.1 kann derzeit die aufgabenspezifische Messunsicherheit von CT-Messungen experimentell durch eine Vielzahl an Wiederholmessungen ermittelt werden. Diese Vorgehensweise ist allerdings kosten- und zeitintensiv. Daher wird die Bestimmung der aufgabenspezifischen Messunsicherheit numerisch durch Simulationen angestrebt (z. B. Leitfaden zur Angabe der Unsicherheit beim Messen (GUM) Supplement 1). Um dieses Ziel zu erreichen, ist es notwendig, einen Digitalen Zwilling von der Messung mit dem verwendeten CT-System zu erstellen. Dieser Beitrag stellt einen ersten Ansatz zur Erstellung eines Digitalen Zwillings vor. Um diesen anschließend zu testen, wurden in einem ersten Test mehrere CT-Scans auf verschiedenen Anlagen durchgeführt und anschließend anhand der verfügbaren Parameter simuliert. Um die Qualität des jeweiligen Digitalen Zwillings einschätzen zu können, wurden die Abweichungen der resultierenden Messwerte von ihren jeweiligen Sollwerten miteinander verglichen. Die Ergebnisse zeigten eine bedingte Übereinstimmung zwischen realen und simulierten Daten. Um diese zu verbessern, wird eine standardisierte Methode zur Charakterisierung der realen CT-Systeme angestrebt. Darüber hinaus sollten Methoden entwickelt werden, die Charakterisierungsparameter in einer Simulationsumgebung hinreichend genau umzusetzen. KW - Computed tomography KW - Measurement uncertainty KW - Simulation KW - Digital twin PY - 2022 DO - https://doi.org/10.1515/teme-2022-0025 SP - 1 EP - 16 PB - De Gruyter CY - Berlin AN - OPUS4-55428 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zutta Villate, J. M. A1 - Viviana Rojas, J. A1 - Hahn, Marc Benjamin A1 - Anselmo Puerta, J. T1 - Synthesis of 198Au nanoparticles sub 10 nm due optimization on local dose by Monte Carlo simulations for cancer treatment N2 - To enhance the biological effects of radiation damage in cancerous cells, we present an alternative approach to the use of gold nanoparticles (AuNP), focusing on the synthesis and characterization of highly monodisperse, spherical radioactive gold nanoparticles 198AuNP. The size of the AuNP size was optimized with the help of Geant4/TOPAS particle scattering simulations, and energy deposition per nm3 per decay for varying radii (2–10 nm) was evaluated. This work is the foundation for ongoing experimental work to evaluate cell death induced by 198AuNP which aims for the use of radioactive gold nanoparticles in cancer treatment. KW - AuNP KW - Beta decay KW - Beta particle KW - Brachytherapy KW - Cancer treatment KW - Nanoparticles KW - Nanoparticle KW - DNA KW - DNA damage KW - Dosimetry KW - Energy deposit KW - Gamma ray KW - Geant4 KW - Geant4-DNA KW - Gold Nanoparticles KW - LEE KW - Low energy electrons KW - MCS KW - Microdosimetry KW - Monte-Carlo simulation KW - NP KW - Synthesis KW - TEM KW - OH radicals KW - Particle scattering KW - Radiation damage KW - Radiationtherapy KW - Radioactive decay KW - Radiolysis KW - Simulation KW - TOPAS KW - TOPAS-nbio PY - 2022 DO - https://doi.org/10.1007/s10967-022-08355-5 SN - 1588-2780 SP - 1 EP - 9 PB - Springer Nature AN - OPUS4-55132 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ahiboz, D. A1 - Andresen, Elina A1 - Manley, P. A1 - Resch-Genger, Ute A1 - Würth, Christian A1 - Becker, C. T1 - Enhanced photon upconversion using erbium-doped nanoparticles interacting with silicon metasurfaces N2 - Photon upconversion (UC) using trivalent erbium (Er+3) doped crystals is a promising concept to harness near infrared photons of the solar spectrum which cannot be directly absorbed by silicon solar cells. However, their UC efficiency at low-intensity 1 sun illumination is not relevant on device level so far. Exploiting giant near-field enhancement effects on metasurfaces is an appealing approach to enable efficient UC at low irradiance conditions. Here, we report on more than 1000-fold enhanced photon UC of NaYF4:Er+3 nanoparticles interacting with the near-fields supported by a silicon metasurface under 1550 nm excitation. T2 - 48th Photovoltaic Specialists Conference (PVSC) CY - Online meeting DA - 20.06.2021 KW - Nano KW - Nanomaterial KW - Upconversion nanoparticle KW - Lanthanide KW - Photoluminescence KW - Quantum yield KW - Photophysics KW - Lifetime KW - Sensor KW - Excitation power density KW - Brightness KW - NIR KW - Mechanism KW - Modeling KW - Simulation KW - Energy transfer KW - Photonic crystal KW - Enhancement strategy PY - 2021 DO - https://doi.org/10.1109/pvsc43889.2021.9518495 SP - 1 EP - 3 PB - IEEE CY - Berlin AN - OPUS4-53786 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grauel, Bettina A1 - Würth, Christian A1 - Homann, C. A1 - Krukewitt, Lisa A1 - Andresen, Elina A1 - Roik, Janina A1 - Recknagel, Sebastian A1 - Haase, M. A1 - Resch-Genger, Ute T1 - Volume and surface effects on two-photonic and three-photonic processes in dry co-doped upconversion nanocrystals N2 - Despite considerable advances in synthesizing high-quality core/shell upconversion (UC) nanocrystals (NC; UCNC) and UCNC photophysics, the application of near-infrared (NIR)-excitable lanthanide-doped UCNC in the life and material sciences is still hampered by the relatively low upconversion luminescence (UCL) of UCNC of small size or thin protecting shell. To obtain deeper insights into energy transfer and surface quenching processes involving Yb3+ and Er3+ ions, we examined energy loss processes in differently sized solid core NaYF4 nanocrystals doped with either Yb3+ (YbNC; 20% Yb3+) or Er3+ (ErNC; 2% Er3+) and co-doped with Yb3+ and Er3+ (YbErNC; 20% Yb3+ and 2% Er3+) without a surface protection shell and coated with a thin and a thick NaYF4 shell in comparison to single and co-doped bulk materials. Luminescence studies at 375 nm excitation demonstrate backenergy transfer (BET) from the 4G11/2 state of Er3+ to the 2F5/2 state of Yb3+, through which the red Er3+ 4F9/2 state is efficiently populated. Excitation power density (P)-dependent steady state and time-resolved photoluminescence measurements at different excitation and emission wavelengths enable to separate surface-related and volume-related effects for two-photonic and threephotonic processes involved in UCL and indicate a different influence of surface passivation on the green and red Er3+ emission. The intensity and lifetime of the latter respond particularly to an increase in volume of the active UCNC core. We provide a threedimensional random walk model to describe these effects that can be used in the future to predict the UCL behavior of UCNC. KW - Nano KW - Nanomaterial KW - Upconversion KW - Nanoparticle KW - Lanthanide KW - Photoluminescence KW - Quantum yield KW - Pphotophysics KW - Lifetime KW - Sensor KW - Excitation KW - Power density KW - Single particle KW - Brightness KW - NIR KW - Mechanism KW - Modeling KW - Simulation KW - Energy transfer PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535317 DO - https://doi.org/10.1007/s12274-021-3727-y SN - 1998-0124 VL - 15 IS - 3 SP - 2362 EP - 2373 PB - Springer AN - OPUS4-53531 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, Marc Benjamin A1 - Zutta Villate, J. M. ED - Zutta Villate, J. M. T1 - Combined cell and nanoparticle models for TOPAS to study radiation dose enhancement in cell organelles N2 - Dose enhancement by gold nanoparticles (AuNP) increases the biological effectiveness of Radiation damage in biomolecules and tissue. To apply them effectively during cancer therapy their influence on the locally delivered dose has to be determined. Hereby, the AuNP locations strongly influence the energy deposit in the nucleus, mitochondria, membrane and the cytosol of the targeted cells. To estimate these effects, particle scattering simulations are applied. In general, different approaches for modeling the AuNP and their distribution within the cell are possible. In this work, two newly developed continuous and discrete-geometric models for simulations of AuNP in cells are presented. These models are applicable to simulations of internal emitters and external radiation sources. Most of the current studies on AuNP focus on external beam therapy. In contrast, we apply the presented models in Monte-Carlo particle scattering simulations to characterize the energy deposit in cell organelles by radioactive 198AuNP. They emit beta and gamma rays and are therefore considered for applications with solid tumors. Differences in local dose enhancement between randomly distributed and nucleus targeted nanoparticles are compared. Hereby nucleus targeted nanoparticels showed a strong local dose enhancement in the radio sensitive nucleus. These results are the foundation for future experimental work which aims to obtain a mechanistic understanding of cell death induced by radioactive 198Au. KW - AuNP KW - Beta decay KW - Brachytherapy KW - Cancer treatment KW - DNA KW - DNA damage KW - Dosimetry KW - Energy deposit KW - Geant4 KW - Geant4-DNA KW - Gold Nanoparticles KW - LEE KW - MCS KW - Microdosimetry KW - Monte-Carlo simulation KW - NP KW - Ectoine KW - OH radicals KW - Radiation damage KW - Radiationtherapy KW - Radioactive decay KW - Simulation KW - Beta particle KW - Clustered nanoparticles KW - Gamma ray KW - Low energy electrons KW - Particle scattering KW - Radiolysis KW - Livermore model KW - Penelope model KW - TOPAS KW - TOPAS-nbio PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523276 DO - https://doi.org/10.1038/s41598-021-85964-2 SN - 2045-2322 VL - 11 IS - 1 SP - 6721 PB - Springer Nature AN - OPUS4-52327 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 - JOUR A1 - Böhne, Chr. A1 - Meschut, G. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - Avoidance of liquid metal embrittlement during resistance spot welding by heat input dependent hold time adaption N2 - Liquid metal embrittlement (LME) cracking can occur during resistance spot welding (RSW) in zinc-coated advanced high-strength steels (AHSS) for automotive production. In this study, a methodological variation of hold time is performed to investigate the process-related crack influence factors. A combination of numerical and experimental investigations confirms, that the extent of heat dissipation and re-heating of the sheet surface can be influenced and thus the degree of crack formation can be controlled in a targeted manner by the parameterisation of the hold time. The temperature and stress history of crack-free and crack-afflicted spot welds are analysed and a conclusion on the borders defining the LME active region is derived. KW - Liquid metal embrittlement KW - Crack KW - Advanced high-strength steels KW - Resistance spot welding KW - Hold time KW - Heat input KW - Simulation PY - 2020 DO - https://doi.org/10.1080/13621718.2020.1795585 SN - 1362-1718 VL - 25 IS - 7 SP - 617 EP - 624 PB - Taylor Francis Online AN - OPUS4-51096 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Aratsu, K. A1 - Takeya, R. A1 - Pauw, Brian Richard A1 - Hollamby, M.J. A1 - Kitamoto, Y. A1 - Shimizu, N. A1 - Takagi, H. A1 - Haruki, R. A1 - Adachi, S. A1 - Yagai, S. T1 - Supramolecular copolymerization driven by integrative self-sorting of hydrogen-bonded rosettes N2 - Molecular recognition to preorganize noncovalently polymerizable supramolecular complexes is a characteristic process of natural supramolecular polymers, and such recognition processes allow for dynamic self-alteration, yielding complex polymer systems with extraordinarily high efficiency in their targeted function. We herein show an example of such molecular recognition-controlled kinetic assembly/disassembly processes within artificial supramolecular polymer systems using six-membered hydrogen-bonded supramolecular complexes (rosettes). Electron-rich and poor monomers are prepared that kinetically coassemble through a temperature-controlled protocol into amorphous coaggregates comprising a diverse mixture of rosettes. Over days, the electrostatic interaction between two monomers induces an integrative self-sorting of rosettes. While the electron-rich monomer inherently forms toroidal homopolymers, the additional electrostatic interaction that can also guide rosette association allows helicoidal growth of supramolecular copolymers that are comprised of an alternating array of two monomers. Upon heating, the helicoidal copolymers undergo a catastrophic transition into amorphous coaggregates via entropy-driven randomization of the monomers in the rosette. KW - Self-assembly KW - Coaggregation KW - Scattering KW - Simulation KW - AFM PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506555 DO - https://doi.org/10.1038/s41467-020-15422-6 VL - 11 IS - 1 SP - Article number: 1623 PB - Springer Nature AN - OPUS4-50655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, Marc Benjamin T1 - Temperature in micromagnetism: Cell size and scaling effects of the stochastic Landau-Lifshitz equation N2 - The movement of the macroscopic magnetic moment in ferromagnetic systems can be described by the Landau-Lifshitz (LL) or Landau-Lifshitz-Gilbert (LLG) equation. These equations are strictly valid only at absolute zero temperature. To include temperature effects a stochastic version of the LL or LLG equation for a spin density of one per unit cell can be used instead. To apply the stochastic LL to micromagnetic simulations, where the spin density per unit cell is generally higher, a conversion regarding simulation cell size and temperature has to be established. Based on energetic considerations, a conversion for ferromagnetic bulk and thin film systems is proposed. The conversion is tested in micromagnetic simulations which are performed with the Object Oriented Micromagnetic Framework (OOMMF). The Curie temperatures of bulk Nickel, Cobalt and Iron systems as well as Nickel thin-film systems with thicknesses between 6.3 mono layer (ML) and 31ML are determined from micromagnetic simulations. The results show a good agreement with experimentally determined Curie temperatures of bulk and thin film systems when temperature scaling is performed according to the presented model. KW - Micromagnetism KW - LLG KW - LL equation KW - Landau Lifshitz equation KW - Landau Lifshitz Gilbert equation KW - Stochastic Landau Lifshitz equation KW - Stochastic Landau Lifshitz Gilbert equation KW - Curie temperature KW - Magnetic Nanoparticles KW - Thin film systems KW - Temeprature scaling KW - Phase transition KW - Magnet coupling KW - Ferromagnetism KW - Superparamagnetism KW - Paramagnetism KW - Ni KW - Co KW - Fe KW - Steel KW - Nickel KW - Cobalt KW - Iron KW - Temperature effects KW - Cell size KW - Damping factor KW - Gamma KW - Alpha KW - Spin KW - Magnetic moment KW - Magnetic interacion KW - Magnetization dynamics KW - Domain wall KW - Exchange length KW - temeprature dependent exchange length KW - Bloch wall KW - Neel wall KW - Exchange interaction KW - Magnetic anisotropy KW - Simulation KW - OOMMF KW - Object oriented micromagnetic framework PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484610 DO - https://doi.org/10.1088/2399-6528/ab31e6 VL - 3 IS - 7 SP - 075009-1 EP - 075009-8 PB - IOPscience CY - England AN - OPUS4-48461 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, Marc Benjamin A1 - Zutta Villate, Julian Mateo T1 - Radioactive gold nanoparticles for cancer treatment: Size and cluster dependent damage studied by Geant4 Monte-Carlo simulations N2 - Dose enhancement by gold nanoparticles (AuNP) was shown to increase the biological effectiveness of radiation damage in biomolecules and tissue. Most of the current studies focus on external beam therapy on combination with AuNP. Here we present a Monte-Carlo study (Geant4) to characterise radioactive AuNP. Radioactive ¹⁹⁸Au emits beta and gamma rays and is considered for applications with solid tumours. To effectively apply ¹⁹⁸AuNP their energy deposit characteristics have to be determined in terms of intrinsic and extrinsic properties e.g. AuNP diameter, AuNP density, and their clustering behaviour. After each decay process, the energy deposit, inelastic scattering events, kinetic energy spectrum of secondary particles within the AuNP themselves and in a spherical target volume of water up to 1 μm radius were determined. Simulations were performed for AuNP radii ranging from 2.5 nm to 20 nm radius, different cluster sizes and densities. The results show an increase of the energy deposit in the vicinity of the AuNP up to 150 nm. This effect nearly vanishes for distances up to one micron. For the case of AuNP clusters and the same activity, the enhancement of the energy deposit increases with the relative gold mass percentage and therefore can be adjusted by changing AuNP radius or clustering behaviour. KW - Gold Nanoparticles KW - AuNP KW - Radioactive decay KW - Beta decay KW - DNA KW - DNA damage KW - Radiation damage KW - MCS KW - Monte-Carlo simulation KW - Geant4 KW - Dosimetry KW - Microdosimetry KW - Cancer treatment KW - Radiationtherapy KW - Brachytherapy KW - OH radicals KW - LEE KW - low energy electrons KW - gamma ray KW - beta particle KW - radiolysis KW - clustered nanoparticles KW - NP KW - Simulation KW - particle scattering KW - Geant4-DNA KW - Energy deposit PY - 2019 DO - https://doi.org/10.1140/epjd/e2019-90707-x SN - 1434-6060 SN - 1434-6079 VL - 73 IS - 5 SP - 95, 1 EP - 7 PB - Springer CY - Berlin Heidelberg AN - OPUS4-47952 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Winkelmann, A. A1 - Britton, T. B. T1 - Constraints on the effective electron energy spectrum in backscatter Kikuchi diffraction N2 - Electron backscatter diffraction (EBSD) is a technique to obtain microcrystallographic information from materials by collecting large-angle Kikuchi patterns in the scanning electron microscope (SEM). An important fundamental question concerns the scattering-angle dependent electron energy distribution, which is relevant for the formation of the Kikuchi diffraction patterns. Here we review the existing experimental data and explore the effective energy spectrum that is operative in the generation of backscatter Kikuchi patterns from silicon. We use a full pattern comparison of experimental data with dynamical electron diffraction simulations. Our energy-dependent cross-correlation based pattern matching approach establishes improved constraints on the effective Kikuchi pattern energy spectrum, which is relevant for high-resolution EBSD pattern simulations and their applications. KW - EBSD KW - Kikuchi pattern KW - Simulation KW - Energy distribution KW - Electron energy PY - 2019 SN - 2469-9950 SN - 2469-9969 VL - 99 IS - 6 SP - 064115-1 EP - 064115-13 PB - AIP AN - OPUS4-47635 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brierley, N. A1 - Bellon, Carsten A1 - Lazaro Toralles, B. T1 - Optimized multi-shot imaging inspection design N2 - The inspection of complex-shaped components, such as those enabled by additive manufacturing, is a major challenge in industrial quality assurance. A frequently adopted approach to volumetric non-destructive evaluation is X-ray computed tomography, but this has major drawbacks. Two-dimensional radiography can overcome some of these problems, but does not generally provide an inspection that is as capable. Moreover, designing a detailed inspection for a complex-shaped component is a labour-intensive task, requiring significant expert input. In response, a computational framework for optimizing the data acquisition for an image-based inspection modality has been devised. The initial objective is to advance the capabilities of radiography, but the algorithm is, in principle, also applicable to alternative types of imaging. The algorithm exploits available prior information about the inspection and simulations of the inspection modality to allow the Determination of the optimal inspection configuration, including specifically component poses with respect to the imaging system. As an intermediate output, spatial maps of inspection performance are computed, for understanding spatially varying limits of detection. Key areas of innovation concern the defect detectability evaluation for arbitrarily complex indications and the creation of an application-specific optimization algorithm. Initial trials of the algorithm are presented, with good results. KW - Inspection design and planning KW - Optimization KW - Radiography KW - Simulation PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-458363 DO - https://doi.org/10.1098/rspa.2017.0319 SN - 1471-2946 SN - 1364-5021 VL - 474 IS - 2216 SP - 70319, 1 EP - 25 PB - The Royal Society CY - London AN - OPUS4-45836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zencker, Uwe A1 - Qiao, Linan A1 - Völzke, Holger T1 - Influence of impact angle and real target properties on drop test results of cubic containers N2 - Drop test scenarios with cubic containers without impact limiters at interim storage sites or in a final repository have been investigated by numerical simulations. An ideally flat drop is impossible to conduct as a free fall of a container even under laboratory conditions. Dynamic stresses and strains inside the container structure are sensitive to the impact angle. Even very small impact angles cause remarkable changes in the experimental or numerical results when a flat bottom or wall of a container hits a flat target. For drop tests with transport packages the International Atomic Energy Agency (IAEA) regulations define an essentially unyielding target. In contrast, potential accident scenarios for storage containers are derived from site-specific safety analyses or acceptance criteria in Germany. Each interim storage site or repository has a yielding or so-called real target with individual structural and material properties. The real target acts as a kind of impact limiter. A more conservative container design is required if the impact limiting effect of the target is not considered. T2 - ASME 2017 Pressure Vessels and Piping Conference CY - Waikoloa, Hawaii, USA DA - 16.07.2017 KW - Finite element method KW - Simulation KW - Drop test KW - Impact angle KW - Real target KW - Yielding target PY - 2017 SN - 978-0-7918-5802-8 DO - https://doi.org/10.1115/PVP2017-65731 VL - 7 SP - Article UNSP V007T07A039, 1 EP - 9 AN - OPUS4-43631 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jensen, S. A. A1 - Rosu, Dana Maria A1 - Hertwig, Andreas A1 - Hansen, P.-E. T1 - Use of Rayleigh-Rice Theory for Analysis of Ellipsometry Data on Rough CIGS Films N2 - Ellipsometry is a useful tool for studying the optical properties of thin films such as photovoltaic devices. We employ Müller matrix ellipsometry to study the thin film photovoltaic material copper indium gallium selenide Cu(In,Ga) Se2 (CIGS), a commercially relevant material with high energy conversion efficiency. Confocal microscopy reveals an rms roughness of 68 nm, which greatly affects the ellipsometry data. Rayleigh-Rice theory is employed to account for the optical properties of the surface roughness in the ellipsometry experiment, and a library search method is used to compare Müller parameters calculated for various CIGS compositions, to the measured data. The Müller parameters calculated with the Rayleigh-Rice model are found to correspond well with the measured data, and a surface roughness of 37nm and a correlation length of 125nm are extracted. KW - Photovoltaics KW - Thin Films KW - Ellipsometry KW - Scattering Theory KW - Optical Wavefield KW - Simulation KW - Müller Polarimetry KW - Multidimensional Spectroscopy PY - 2017 DO - https://doi.org/10.1002/pssc.201700217 SN - 1862-6351 VL - 14 IS - 12 SP - 1700217, 1 EP - 5 PB - WILEY-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-43390 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 - JOUR A1 - Ertel, Jens-Peter A1 - Niederleithinger, Ernst A1 - Grohmann, Maria T1 - Advances in pile integrity testing N2 - For decades, the low-strain impact integrity testing using a hammer blow is well established as a method of quality assurance for various pile types. However, this method has its limitations. Our research and development focuses on improving the excitation signal using a shaker system in contrast to the standard hammer method. Another approach is to increase the amount of sensors used during testing. The purpose is to identify the direction of wave propagation which gives advantages under difficult conditions, such as piles below structures. Pile integrity testing (PIT) using a shaker system was performed on two 11 m long piles of 90 cm in diameter. While one pile was intact, the other one showed a flaw at approx. 3.5 m below pile top, which was confirmed by standard PIT in 2012. A logarithmic sweep between 500 Hz and 1 KHz of 0.1 s was used as the input signal, being vertically injected into the pile. Prior to that, simulations on similar pile geometries showed that the depth of the pile toe as well as flaws within the pile can be extracted by applying regularized deconvolution. The result is the impulse response in the time domain. The application of deconvolution on the measured signals shows that it is possible to identify the pile length but it is more difficult to clearly extract the flaw’s position in the pile. Additional digital signal processing techniques and the improvement of the regularized deconvolution method as well as the experimental setup need to be investigated. Another way to improve the PIT method is to use a multichannel sensor arrangement. By arranging several accelerometers vertically along the accessible part of the pile shaft, it is possible to distinguish between downward and upward traveling waves. Furthermore, it is possible to estimate the unknown wave speed, which gives the possibility of more accurate pile length calculations. The method was evaluated successfully during a measurement campaign of a slab foundation with subjacent piles. In 20 of 28 cases the pile length could be detected accurately. KW - Pile integrity testing KW - Pile length KW - CEFIT KW - Deconvolution KW - Simulation PY - 2016 UR - http://nsg.eage.org/publication/publicationdetails/?publication=86879 SN - 1569-4445 SN - 1873-0604 VL - 14 IS - 6 SP - 503 EP - 512 PB - EAGE Publications AN - OPUS4-37837 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Winkelmann, Aimo A1 - Nolze, Gert A1 - Voss, M. A1 - Salvat-Pujol, F. A1 - Werner, W. S. M. T1 - Physics-based simulation models for EBSD: advances and challenges N2 - EBSD has evolved into an effective tool for microstructure investigations in the scanning electron microscope. The purpose of this contribution is to give an overview of various simulation approaches for EBSD Kikuchi patterns and to discuss some of the underlying physical mechanisms. T2 - EMAS 2015 - 14th European Workshop on MODERN DEVELOPMENTS AND APPLICATIONS IN MICROBEAM ANALYSIS CY - Portoroz, Slovenia DA - 03.05.2015 KW - Electron backscatter diffraction KW - Simulation KW - Dynamical theory KW - Kinematic theory PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-377469 DO - https://doi.org/10.1088/1757-899X/109/1/012018 VL - 109 SP - 012018-1 EP - 012018-13 AN - OPUS4-37746 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bachmann, Marcel A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Welding with high-power lasers: trends and developments N2 - High-power laser beam welding became new stimuli within the last 10 years due to the availability of a new generation of high brightness multi kilowatt solid state lasers. In the welding research new approaches have been developed to establish reliable and praxis oriented welding processes meeting the demands of modern industrial applications during this time. The paper focuses on some of the current scientific and technological aspects in this research field like hybrid laser arc welding, simulation techniques, utilization of electromagnetic fields or reduced pressure environment for laser beam welding processes, which contributed to the further development of this technology or will play a crucial role in its further industrial implementation. T2 - 9th International Conference on Photonic Technologies - LANE 2016 CY - Fürth, Germany DA - 19.09.2016 KW - High-power Laserbeam Welding KW - Electromagnetic Force KW - Vacuum KW - Simulation PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-377280 DO - https://doi.org/10.1016/j.phpro.2016.08.003 VL - 83 SP - 15 EP - 25 PB - Elsevier B.V. CY - Berlin, Germany AN - OPUS4-37728 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 - Hartmann, S A1 - Sturm, Heinz A1 - Blaudeck, T A1 - Hoelck, O A1 - Hermann, S A1 - Schulz, SE A1 - Wunderle, B. T1 - Experimental and computational studies on the role of surface functional groups in the mechanical behavior of interfaces between single-walled carbon nanotubes and metals N2 - To study the mechanical interface behavior of single-walled carbon nanotubes (CNTs) embedded in a noble metal, we performed CNT-metal pull-out tests with in situ scanning electron microscope experiments. Molecular dynamics (MD) simulations were conducted to predict force-displacement data during pull-out, providing critical forces for failure of the system. In MD simulations, we focused on the influence of carboxylic surface functional groups (SFGs) covalently linked to the CNT. Experimentally obtained maximum forces between 10 and 102 nN in palladium and gold matrices and simulated achievable pulling forces agree very well. The dominant failure mode in the experiment is CNT rupture, although several pull-out failures were also observed. We explain the huge scatter of experimental values with varying embedding length and SFG surface density. From simulation, we found that SFGs act as small anchors in the metal matrix and significantly enhance the maximum forces. This interface reinforcement can lead to tensile stresses sufficiently high to initiate CNT rupture. To qualify the existence of carboxylic SFGs on our CNT material, we performed analytical investigation by means of fluorescence labeling of surface species and discuss the results. With this contribution, we focus on a synergy between computational and experimental approaches involving MD simulations, nano scale testing, and analytics (1) to predict to a good degree of accuracy maximum pull-out forces of single-walled CNTs embedded in a noble metal matrix and (2) to provide valuable input to understand the underlying mechanisms of failure with focus on SFGs. This is of fundamental interest for the design of future mechanical sensors incorporating piezoresistive single-walled CNTs as the sensing element. KW - Oxygen-containing functionalities KW - Molecular-dynamics KW - Structural characterization KW - Reinforced composites KW - Raman spectroscopy KW - Shear strength KW - Polymer matrix KW - Pull-out KW - Simulation KW - Purification PY - 2016 DO - https://doi.org/10.1007/s10853-015-9142-6 SN - 0022-2461 SN - 1573-4803 VL - 51 IS - 3 SP - 1217 EP - 1233 AN - OPUS4-35795 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zencker, Uwe A1 - Qiao, Linan A1 - Völzke, Holger T1 - Dynamic finite element analysis of cask handling accidents at storage sites N2 - The safety assessment of casks for radioactive material at interim storage facilities or in final repositories includes the investigation of possible handling accidents if clearly defined test conditions are not available from the regulations. Specific handling accidents usually are the drop of a cask onto the transport vehicle or the floor as well as the collision with the wall of the storage building or another cask. For such load cases an experimental demonstration of cask safety would be difficult. Therefore, numerical analyses of the entire load scenario are preferred. The lessons learnt from dynamic finite element analyses of accident scenarios with thick-walled cubical containers or cylindrical casks are presented. The dependency of calculation results on initial and boundary conditions, material models, and contact conditions is discussed. Parameter sets used should be verified by numerical simulation of experimentally investigated similar test scenarios. On the other hand, decisions have to be made whether a parameter or property is modeled in a realistic or conservative manner. For example, a very small variation of the initial impact angle of a container can cause significantly different stresses and strains. In sophisticated cases an investigation of simpler limit load scenarios could be advantageous instead of analyzing a very complicated load scenario. T2 - ASME 2015 Pressure vessels & piping conference - PVP2015 CY - Boston, Massachusetts, USA DA - 19.07.2015 KW - Finite element method KW - Simulation KW - Cask handling accident KW - Interim storage PY - 2015 SN - 978-0-7918-5702-1 SP - Paper 45606, 1 EP - 10 AN - OPUS4-34937 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kempel, Florian A1 - Schartel, Bernhard A1 - Marti, J.M. A1 - Butler, K.M. A1 - Rossi, R. A1 - Idelsohn, S.R. A1 - Onate, E. A1 - Hofmann-Böllinghaus, Anja T1 - Modelling the vertical UL 94 test: competition and collaboration between melt dripping, gasification and combustion N2 - An experimental and numerical investigation of the effect of bisphenol A bis(diphenyl phosphate) (BDP) and polytetrafluoroethylene (PTFE) on the fire behaviour of bisphenol A polycarbonate/acrylonitrile butadiene styrene (PC/ABS) in the vertical UL 94 scenario is presented. Four PC/ABS blends were discussed, which satisfy different UL 94 classifications due to the competing effects of gasification, charring, flame inhibition and melt flow/dripping. For numerical investigation, the particle finite element method (PFEM) is used. Its capability to model the complex fire behaviour of polymers in the UL 94 is analysed. The materials' properties are characterised, in particular the additives impact on the dripping behaviour during thermal exposure. BDP is an efficient plasticiser; adding PTFE prevents dripping by causing a flow limit. PFEM simulations reproduce the dripping and burning behaviour, in particular the competition between gasification and dripping. The thermal impact of both the burner and the flame is approximated taking into account flame inhibition, charring and effective heat of combustion. PFEM is a promising numerical tool for the investigation of the fire behaviour of polymers, particularly when large deformations are involved. Not only the principal phenomena but also the different UL 94 classifications and the extinction times are well predicted. KW - Melt dripping KW - UL 94 KW - Particle finite element method (PFEM) KW - Simulation KW - Bisphenol A polycarbonate/acrylonitrile butadiene styrene (PC/ABS) KW - Polytetrafluoroethylene (PTFE) KW - Bisphenol A bis(diphenyl phosphate) (BDP) PY - 2015 DO - https://doi.org/10.1002/fam.2257 SN - 0308-0501 SN - 1099-1018 VL - 39 IS - 6 SP - 570 EP - 584 PB - Heyden CY - London AN - OPUS4-34285 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geoerg, Paul A1 - Rost, M. A1 - Krause, U. A1 - Hofmann-Böllinghaus, Anja T1 - Vergleichende Untersuchung zur Personensicherheit am Beispiel eines Seminarraumes N2 - Um den Anforderungen der Bauordnung an den Brandschutz für Gebäude gerecht zu werden, sind bauliche Anlagen so zu errichten und zu betreiben, dass der Entstehung eines Brandes und der Ausbreitung von Feuer und Rauch vorgebeugt, die Rettung von Menschen und Tieren sowie wirksame Löscharbeiten ermöglicht werden. Hierbei besteht, einer steigenden Komplexität sowie einem differenzierten Nutzungskonzept öffentlicher Gebäude geschuldet, häufig die Notwendigkeit von normativen Vorgaben abzuweichen und dennoch ein gleichwertiges Sicherheitsniveau nachzuweisen. Es werden Personensimulationsmodelle eingesetzt, die einerseits das Vorhandensein eines Schutzzielniveaus durch die Abbildungen von Personenbewegungen nachweisen können und andererseits durch Parametervariation eine szenarienabhängige Betrachtung ermöglichen. Der vorliegende Beitrag vergleicht die Ergebnisse einer kleinskaligen Evakuierungsübung mit drei mikroskopischen Personensimulationsmodellen und geht der Frage nach der Aussagekraft dieser Bewertungsmethode nach. Es zeigt sich, dass die alleinige Betrachtung absoluter Entleerungszeiten keine zuverlässige Beurteilungsgrundlage für das komplexe Schutzziel Personensicherheit darstellt. T2 - 4. Magdeburger Brand- und Explosionsschutztag / 3. vfdb-Workshop Brandschutzforschung CY - Magdeburg, Germany DA - 26.03.2015 KW - Evakuierung KW - Routenwahl KW - Fußgänger KW - Sicherheit KW - Simulation PY - 2015 SN - 978-3-00-048960-0 SP - 1 EP - 13 AN - OPUS4-33123 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pelkner, Matthias A1 - Erthner, Thomas A1 - Reimund, Verena A1 - Kreutzbruck, Marc A1 - Sergeeva-Chollet, N. T1 - MR-based eddy current probe design for hidden defects N2 - We present a simulation study which pursues the objective to find probe geometries for a MR-based eddy current (EC) probe (MR magneto resistance, e.g., GMR giant magneto resistance, TMR tunnel magneto resistance). MR sensor technology exhibits two significant advantages compared with conventional coil systems. First, MR sensors are relatively frequency-independent within common EC-frequency ranges which enable us to operate them in hidden defects testing problems. Secondly, MR technology is well suited for miniaturization helping us to design small elements in the order of below 100 µm. In this paper simulation and experimental results obtained with the probes for low frequency application, i.e. for hidden defects detection are discussed. Our simulations are based on two different approaches for a better validation, a commercial finite element method software (Opera, Vectorfields) and the semi-analytical software CIVA. We investigated both coil arrangement in order to excite sufficient high eddy currents inside the test samples and position of MR-elements at the array chip. In doing so the MR sensors were positioned that they are not exposed to excitation fields. In addition, different coil geometries, in particular coil length, e.g. Ι = 20 mm, were analyzed in order to generate a consistent eddy current distribution beneath an array of up to 32 MR-elements. To prove obtained probe principles we built GMR-EC-probes. The first test measurements are in good agreement with the simulations performed by BAM and CEA. On basis of our findings the IMAGIC consortium developed new MR-EC-probes using integrated ASIC technology. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - Magneto resistance (MR) KW - Eddy current (EC) KW - Simulation KW - GMR KW - Magnetic flux leakage KW - Hidden defects PY - 2014 UR - http://www.ndt.net/events/ECNDT2014/app/content/Paper/409_Pelkner.pdf SN - 978-80-214-5018-9 SP - 1 EP - 8 AN - OPUS4-32231 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ewert, Uwe A1 - Deresch, Andreas A1 - Bellon, Carsten A1 - Jaenisch, Gerd-Rüdiger ED - Chimenti, D.E. ED - Bond, L.J. ED - Thompson, D.O. T1 - A benchmark concept for simulation in radiographic testing N2 - The new standard ISO 17636–2:2013 'NDT of welds: Radiographic testing - Part 2: X- and gamma ray techniques with digital detectors' describes a complex procedure for film replacement by phosphor imaging plates and digital detector arrays. RT modeling software should consider these detector types, X-ray film, and the standard requirements for image quality. Practitioners expect the same visibility of image quality indicators (IQI) in the simulated radiographs as in the experimental exposures. The proposed benchmark test is based on the comparison of experimental radiographs taken at BAM with modeled ones of participants. The experimental setup and the determination of the equivalent penetrameter sensitivity (EPS) as described in the procedure of ASTM E 746 are used for quantitative evaluation of the achievable contrast sensitivity for step hole IQIs as considered in Annex B of ISO 17636-2. System classification data for Computed Radiography (CR) and film systems will be provided by BAM according to ISO 11699–1 for selected film systems and according to ASTM E 2446 for selected CR systems. The classification of films and digital detectors is based on the measurement of the dose response function, the basic spatial resolution (SRb) of the image, and the measured image noise, which depends on the detector efficiency, the quantum statistics, and the detector fixed pattern noise. T2 - 40th Annual review of progress in quantitative nondestructive evaluation CY - Baltimore, Maryland, USA DA - 21.07.2013 KW - Digital radiography KW - Computed radiography KW - Benchmark KW - EPS KW - Modeling KW - Simulation KW - Contrast to noise ratio KW - Observer model PY - 2014 SN - 978-0-7354-1212-5 SN - 978-0-7354-1211-8 DO - https://doi.org/10.1063/1.4865044 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 33A SP - 1816 EP - 1823 PB - AIP Publishing AN - OPUS4-30904 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaenisch, Gerd-Rüdiger A1 - Deresch, Andreas A1 - Bellon, Carsten A1 - Schumm, A. A1 - Guerin, P. ED - Chimenti, D.E. ED - Bond, L.J. ED - Thompson, D.O. T1 - A proposed benchmark for simulation in radiographic testing N2 - The purpose of this benchmark study is to compare simulation results predicted by various models of radiographic testing, in particular those that are capable of separately predicting primary and scatter radiation for specimens of arbitrary geometry. T2 - 40th Annual review of progress in quantitative nondestructive evaluation CY - Baltimore, Maryland, USA DA - 21.07.2013 KW - Benchmark KW - Simulation KW - Radiographic testing PY - 2014 SN - 978-0-7354-1212-5 SN - 978-0-7354-1211-8 DO - https://doi.org/10.1063/1.4865082 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 1581 SP - 2101 EP - 2106 PB - AIP Publishing AN - OPUS4-30756 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stindt, Arne A1 - Andrade, M. A. B. A1 - Buurman, Merwe A1 - Adamowski, J. C. A1 - Panne, Ulrich A1 - Riedel, Jens T1 - Experimental and numerical characterization of the sound pressure in standing wave acoustic levitators N2 - A novel method for predictions of the sound pressure distribution in acoustic levitators is based on a matrix representation of the Rayleigh integral. This method allows for a fast calculation of the acoustic field within the resonator. To make sure that the underlying assumptions and simplifications are justified, this approach was tested by a direct comparison to experimental data. The experimental sound pressure distributions were recorded by high spatially resolved frequency selective microphone scanning. To emphasize the general applicability of the two approaches, the comparative studies were conducted for four different resonator geometries. In all cases, the results show an excellent agreement, demonstrating the accuracy of the matrix method. KW - Acoustic levitation KW - Matrix calculation KW - Microphony KW - Noncontact ultrasonic transportation KW - Small objects KW - Matrix-method KW - Droplets KW - Air KW - Manipulation KW - Simulation KW - Fields KW - Water PY - 2014 DO - https://doi.org/10.1063/1.4861197 SN - 0034-6748 SN - 1089-7623 N1 - Geburtsname von Buurman, Merwe: Albrecht, M. - Birth name of Buurman, Merwe: Albrecht, M. VL - 85 IS - 015110 SP - 1 EP - 6 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-30405 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gravenkamp, Hauke A1 - Song, C. A1 - Prager, Jens T1 - Numerical simulation of ultrasonic guided waves using the scaled boundary finite element method N2 - The formulation of the Scaled Boundary Finite Element Method is applied for the computation of dispersion properties of ultrasonic guided waves. The cross-section of the waveguide is discretized in the Finite Element sense, while the direction of propagation is described analytically. A standard eigenvalue problem is derived to compute the wave numbers of propagating modes. This paper focuses on cylindrical waveguides, where only a straight line has to be discretized. Higher-order elements are utilized for the discretization. As examples, dispersion curves are computed for a homogeneous pipe and a layered cylinder. T2 - 2012 IEEE International Ultrasonics Symposium (IUS) CY - Dresden, Germany DA - 07.10.2012 KW - Guided waves KW - Simulation KW - Dispersion KW - Scaled boundary finite element method PY - 2012 SN - 978-1-4673-4562-0 DO - https://doi.org/10.1109/ULTSYM.2012.0673 SN - 1948-5719 SP - 2686 EP - 2689 AN - OPUS4-29665 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Habib, Abdel Karim A1 - Schalau, Bernd A1 - Schmidt, Dirk ED - Pierucci, S. ED - Klemes, J.J. ED - De Rademaeker, E. ED - Fabiano, B. ED - Buratti, S.S. T1 - Comparing different methods for calculating the gas dispersion N2 - When handling flammable and/or toxic liquids or gases, the gas dispersion following a release of substance is a scenario to be considered in the risk assessment to determine the lower flammability distance (LFD) and toxicity thresholds. In this work a comparison of different gas dispersion tools of varying complexity ranging from a simple Gaussian model over a boundary layer model (BLM) and a Lagrangian model to CFD (in this case ANSYS CFX v14) is presented. The BLM covers the special case of liquid releases with formation of a pool. It does not only solve the gas dispersion but also calculates the evaporating mass flow out of the pool. The simulation values are compared to each other and to experimental data resulting mainly from our own open air experiments covering the near field and carried out on the Test Site Technical Safety of BAM (BAM-TTS) for different release types (pool evaporation, gas release) and topologies. Other validation data were taken from literature and cover large scale experiments in the range of several 100 m. T2 - 14th International symposium on loss prevention and safety promotion in the process industries CY - Florence, Italy DA - 12.05.2013 KW - Gas dispersion KW - Simulation PY - 2013 SN - 978-88-95608-22-8 SN - 1974-9791 N1 - Serientitel: Chemical engineering transactions – Series title: Chemical engineering transactions IS - 31 SP - 1 EP - 6 PB - AIDIC, Associazione Italiana di Ingegneria Chimica CY - Milano AN - OPUS4-29587 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Menrad, Andreas A1 - Goedecke, Thomas A1 - Gründer, Klaus-Peter A1 - Wagner, M.H. T1 - The internal pressure test in experiment and simulation - Influence of the wall thickness variation and the change of the packaging behavior after the impact of standard liquids N2 - The effect of the wall thickness variation of blow-moulded bodies made of high-density polyethylene on an internal pressure test after prestoring the packaging with standard liquids was evaluated in experiments and simulations. The objects of the investigation were jerrycans used for the transportation and storage of dangerous goods. The wall thickness was determined using two alternative methods to the magnetostatic measurement. These alternative methods are used for research purpose to get a volumetric model of the jerrycan wall as a geometric model for the simulation. The comparison of the experiments and the simulations of the internal pressure test were performed using the digital image correlation method. The integral strain and deformation of the whole jerrycan was detected by measuring the total mass of the jerrycan being filled with water during the internal pressure test. This is a suitable alternative to the optical measurements of local deformation by the digital image correlation method. Prestorage at 40°C without the influence of chemicals strengthens the jerrycan, whereas the swelling effect of butyl acetate and hydrocarbon mixture softens the jerrycan. The comparison with the experiment is necessary to verify the accuracy of the simulation. It shows that the deformation can be simulated more precisely by using the actual measured geometry. The weakening of the high-density polyethylene caused by a hydrocarbon mixture can be simulated using the Arrhenius equation. The aim of the simulation was to discover whether it is possible to use specimens to predict the behaviour of a packaging both after the influence of standard liquids. T2 - 18th IAPRI World packaging conference CY - San Luis Obispo, CA, USA DA - 17.06.2012 KW - Wall thickness KW - Internal pressure test KW - Finite element KW - Simulation KW - Jerrycan PY - 2013 DO - https://doi.org/10.1002/pts.1983 SN - 0894-3214 VL - 26 IS - 6 SP - 311 EP - 326 PB - Wiley CY - Chichester, UK AN - OPUS4-29282 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brauser, Stephan A1 - Gebhardt, Moritz Oliver A1 - Rethmeier, Michael ED - Babu, S. S. ED - Bhadeshia, H.K. ED - Cross, C.E. ED - David, S.A. ED - DebRoy, T. ED - DuPont, J.N. ED - Koseki, T. ED - Liu, S. T1 - Influence of imperfections on the fatigue performance of resistance spot welded joints N2 - In this study, the influence of two different types of weld imperfections, i.e. production-related gaps and weld cracks, on the fatigue performance was investigated for resistance spot welded TRIP steel HCT690. It was ascertained that gaps of 3 mm lead to a significant drop in fatigue life compared to gap free shear tension samples under a load ratio R of 0.1. This fact was attributed to decreased stiffness, higher transverse vibration and higher rotation () between the sheets. Furthermore, FE-simulations have shown an increase in local stresses in gapped samples. The investigation into the influence of cracks was split depending on the crack location in the weld area. Surface cracks in the electrode indentation area as well as in the HAZ were produced and analyzed. The results showed that surface cracks independent of their position have no effect on the fatigue life. The produced internal imperfections have shown only a marginal impact on the fatigue life. By using a 3D FE-simulation of crack containing samples and crack free samples the influence of such imperfections was validated by determining the local stresses in critical areas. T2 - 9th International conference on trends in welding research CY - Chicago, Illinois, USA DA - 04.06.2012 KW - Resistance spot welding KW - Gaps KW - Cracks KW - Fatigue life KW - Simulation PY - 2013 SN - 978-1-62708-998-2 SP - 650 EP - 660 PB - ASM international AN - OPUS4-29056 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gravenkamp, Hauke A1 - Man, H. A1 - Song, C. A1 - Prager, Jens T1 - The computation of dispersion relations for three-dimensional elastic waveguides using the scaled boundary finite element method N2 - In this paper, a numerical approach for the computation of dispersion relations for three-dimensional waveguides with arbitrary cross-section is proposed. The formulation is based on the Scaled Boundary Finite Element Method (SBFEM). It is an extension of the approach previously derived for plate structures. It is shown that the wavenumbers of guided waves in a waveguide can be obtained as the eigenvalues of the Z matrix, which is well known in the SBFEM. The Hamiltonian properties of this matrix are utilized to derive an efficient way to compute the group velocities of propagating waves as eigenvalue derivatives. The cross-section of the waveguide is discretized using higher-order spectral elements. It is discussed in detail how symmetry axes can be utilized to reduce computational costs. In order to sort the solutions at different frequencies, a mode-tracking algorithm is proposed, based on the Padé expansion. KW - Guided waves KW - Simulation KW - Dispersion KW - Scaled boundary finite element method PY - 2013 DO - https://doi.org/10.1016/j.jsv.2013.02.007 SN - 0022-460X SN - 1095-8568 VL - 332 IS - 15 SP - 3756 EP - 3771 PB - Academic Press CY - London AN - OPUS4-28837 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mente, Tobias A1 - Böllinghaus, Thomas T1 - Modeling of hydrogen distribution in a duplex stainless steel N2 - Quite a number of models for hydrogen distribution in steels and welds have been developed in the past 20 years. They reach from simple analytical models to more complex two and three dimensional finite element simulations. So far, these models have been used to simulate hydrogen distribution in homogeneous microstructure. This paper contributes to numerical simulation of hydrogen distribution in heterogeneous microstructure, e. g. in a duplex stainless steel microstructure consisting of two phase fractions. Under appropriate conditions, such as cathodic protection, it is possible that hydrogen is absorbed leading to material embrittlement and possibly initiating hydrogen assisted cracking. In order to avoid hydrogen assisted cracking in duplex stainless steels, it is of great interest to know more about the diffusion behavior of the ferrite and austenite phase. A numerical model has been developed that operates on the mesoscale and enables simulation of hydrogen transport in the various phases of a metallic material. As a first application of this model, hydrogen distribution in a duplex stainless steel 1.4462, consisting of approximately equal portions of ferrite and austenite, was simulated using the finite element program package ANSYS. The results reflect the dependency of hydrogen distribution on the microstructural alignment of the ferrite and austenite phase fractions. Crack-critical areas can thus be identified, provided the critical strain-hydrogen combination is known for the respective microstructural phase. KW - Finite element KW - Simulation KW - Duplex stainless steel KW - Hydrogen KW - Diffusion KW - Weld metal KW - Microstructure PY - 2012 SN - 0043-2288 SN - 1878-6669 VL - 56 IS - 11/12 SP - 66 EP - 78 PB - Springer CY - Oxford AN - OPUS4-27483 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scharkoi, O. A1 - Esslinger, Susanne A1 - Becker, Roland A1 - Weber, M. A1 - Nehls, Irene T1 - Phase I oxidation of alpha- and gamma-hexabromocyclododecane by cytochrome P450 enzymes: simulation of the steroisomerism of hydroxylated metabolites T2 - DIOXIN 2011 CY - Brussels, Belgium DA - 2011-08-21 KW - Bromierte Falmmschutzmittel KW - Hexabromcyclododecan KW - Cytochrom KW - Metaboliten KW - HPLC KW - Simulation PY - 2011 UR - http://www.dioxin20xx.org/pdfs/2011/1810.pdf SN - 1026-4892 VL - 73 SP - 730 EP - 733 AN - OPUS4-27263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Österle, Werner A1 - Dmitriev, A.I. A1 - Kloß, Heinz T1 - Does ultra-mild wear play any role for dry friction applications, such as automotive braking? N2 - Nanostructured third body films and/or storage of wear debris at the surfaces of the first bodies are deemed as prerequisites of sliding under ultra-mild wear conditions. Since such features have been observed experimentally on brake pads and discs, attempts were undertaken to study their sliding behaviour by modelling on the nanoscopic scale with an approach based on Movable Cellular Automata (MCA). The model rendered the possibility to study the influence of different nanostructures systematically and to assess the impact of different brake pad ingredients on the sliding behaviour, velocity accommodation and friction force stabilization at a sliding contact. Besides providing a review on previously published modelling results, some additional new graphs enabling better visualization of dynamic processes are presented. Although ultra-mild wear conditions were considered to be essential for achieving the desired tribological properties, transitions to mesoscopic and macroscopic wear mechanisms were studied as well. The final conclusion is that ultra-mild wear and corresponding smooth sliding behaviour play an important role during automotive braking, even though temporarily and locally events of severe wear may cause friction instabilities, surface damage and release of coarse wear particles. KW - Dry friction KW - Ultra-mild wear KW - Third body KW - MCA-model KW - Simulation PY - 2012 DO - https://doi.org/10.1039/c2fd00117a SN - 1359-6640 SN - 1364-5498 VL - 156 IS - 0 SP - 159 EP - 171 PB - Soc. CY - Cambridge [u.a.] AN - OPUS4-26822 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gollwitzer, Christian A1 - Bellon, Carsten A1 - Deresch, Andreas A1 - Ewert, Uwe A1 - Jaenisch, Gerd-Rüdiger A1 - Zscherpel, Uwe A1 - Mistral, Q. ED - Thompson, D. O. ED - Chimenti, D. E. T1 - Simulation supported POD for RT test case - concept and modeling N2 - Within the framework of the European project PICASSO, the radiographic simulator aRTist (analytical Radiographic Testing inspection simulation tool) developed by BAM has been extended for reliability assessment of film and digital radiography. NDT of safety relevant components of aerospace industry requires the proof of probability of detection (POD) of the inspection. Modeling tools can reduce the expense of such extended, time consuming NDT trials, if the result of simulation fits to the experiment. Our analytic simulation tool consists of three modules for the description of the radiation source, the interaction of radiation with test pieces and flaws, and the detection process with special focus on film and digital industrial radiography. It features high processing speed with near–interactive frame rates and a high level of realism. A concept has been developed as well as a software extension for reliability investigations, completed by a user interface for planning automatic simulations with varying parameters and defects. Furthermore, an automatic image analysis procedure is included to evaluate the defect visibility. The radiographic modeling from 3D CAD of aero engine components and quality test samples are compared as a precondition for real trials. This enables the evaluation and optimization of film replacement for application of modern digital equipment for economical NDT and defined POD. T2 - 38th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Burlington, VT, USA DA - 2011-07-17 KW - X-ray imaging KW - Probability of detection KW - Simulation KW - ZfP KW - Radiographie KW - POD PY - 2012 SN - 978-0-7354-1013-8 DO - https://doi.org/10.1063/1.4716283 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 31 IS - 1430 SP - 605 EP - 612 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-26696 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Qiao, Linan A1 - Zencker, Uwe A1 - Völzke, Holger A1 - Wille, Frank A1 - Musolff, André ED - Topping, B.H.V. T1 - Validation of numerical simulation models for transport and storage casks using drop test results N2 - The safety assessment of new designs for transport and storage casks for radioactive materials is a challenging task accomplished using different methods such as prototype tests, model tests, calculations and analogy reflections. At BAM (Federal Institute for Materials Research and Testing), the test procedures for the mechanical IAEA (International Atomic Energy Agency) test conditions often start with preliminary finite element (FE) calculations mostly with a small-scale cask model for verification of the proposed test cask instrumentation and test plan. On that basis the extensive test cask instrumentation is applied and checked. After that, a series of drop tests consisting of different test sequences is performed. Following the drop tests, numerical post-analyses are carried out. These analyses offer the possibility of a detailed calculation and assessment of stresses and strains in the entire test cask construction. The calculation results have to be carefully compared with the measurement data over the impact history to find out all relevant parameters for a realistic simulation of the impact scenario. The desired ideal boundary test conditions often cannot be met exactly during the drop tests. Therefore, the numerical post-analyses are carried out by using the real boundary conditions of the drop tests. The objective is to find a validated model, where the results of the numerical simulations satisfactorily meet the experimental results. Under test conditions according to the IAEA transport regulations, casks are usually equipped with impact limiters and dropped onto a so-called unyielding target. In general, it is difficult to verify a complex FE model by using results from only one drop test because of the complex impact process and the complex structure of such packages. After each drop test, numerical post-analyses should be carried out. Only if all drop tests were simulated successfully by using the same FE model under different test conditions, it is possible to obtain a validated numerical model for further investigations. In this case the results of the numerical simulations meet satisfactorily the experimental results. In this paper a study is presented, where the influence of different components on the cask loading is investigated systematically. T2 - 11th International conference on computational structures technology CY - Dubrovnik, Croatia DA - 04.09.2012 KW - Impact KW - Simulation KW - Cask KW - Dop test KW - Finite element model KW - Validation KW - Dynamics KW - Transport and storage cask PY - 2012 DO - https://doi.org/10.4203/ccp.99.273 SN - 1759-3433 IS - Paper 273 SP - 1 EP - 12 PB - Civil Comp Press AN - OPUS4-26537 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gravenkamp, Hauke A1 - Saputra, A. A. A1 - Song, C. A1 - Prager, Jens ED - Linde, B. B. J. ED - Paczkowski, J. ED - Ponikwicki, N. T1 - Detection of defects in thin-walled structures by means of lamb waves N2 - In this paper the Scaled Boundary Finite Element Method (SBFEM) is applied for the simulation of Lamb waves in cracked plates. This method is highly advantageous to study the interaction of different Lamb wave modes with cracks as the crack is not discretized and no refinement is required around the crack tip. Numerical examples are presented for the reflection of the fundamental symmetric and antisymmetric modes from cracks of different depth. The spatial Fourier transformation is employed to calculate the amplitudes of reflected Lamb wave modes. The results reveal possibilities to obtain details of the crack geometry in non-destructive testing and structural health monitoring applications. T2 - International congress on ultrasonics CY - Gdansk, Poland DA - 05.09.2011 KW - Lamb waves KW - Scaled boundary finite element method KW - Simulation KW - Crack detection PY - 2012 SN - 978-0-7354-1019-0 DO - https://doi.org/10.1063/1.3703223 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1433 SP - 443 EP - 446 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-26203 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vöse, Markus A1 - Fedelich, Bernard A1 - Owen, J. T1 - A simplified model for creep induced grain boundary cavitation validated by multiple cavity growth simulations N2 - Simulations of cavitation processes on a grain boundary under creep conditions have been carried out, taking into account nucleation, growth, coalescence and sintering of multiple cavities. Cavity growth rates have been calculated through a resolution procedure based on the use of holomorphic complex functions. Three dimensionless parameters have been identified that are responsible for the cavitation development. Parameter studies have been carried out in order to characterise the mechanisms that are responsible for the cavitation development. These studies have been used to develop a physically motivated, simplified model in order to describe the cavitation development of the simulations in terms of global state variables. The simplified model is able to reproduce the cavitation development for all considered combinations of the dimensionless parameters and allows the description of the thickening behaviour of a cavitating grain boundary. KW - Creep damage KW - Grain boundary diffusion KW - Cavitation KW - Simulation PY - 2012 DO - https://doi.org/10.1016/j.commatsci.2012.01.033 SN - 0927-0256 VL - 58 SP - 201 EP - 213 PB - Elsevier CY - Amsterdam AN - OPUS4-25630 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vasilic, Ksenija A1 - Meng, Birgit A1 - Kühne, Hans-Carsten A1 - Roussel, N. T1 - Flow of fresh concrete through steel bars: a porous medium analogy N2 - Although being a very promising area of concrete technology, computational modeling of fresh concrete flow is a comprehensive and time consuming task. The complexity and required computation time are additionally increased when simulating casting of heavily reinforced sections, where each single reinforcement bar has to be modeled. In order to improve the computation speed and to get closer to a practical tool for simulation of casting processes, an innovative approach to model reinforced sections is proposed here. The basic idea of this approach is to treat the reinforcement zone as a porous medium in which a concrete is propagating. In the present paper, the numerical implementation of this concept is described. A methodology allowing for the computation of the equivalent permeability of the steel bars network is suggested. Finally, this numerical technique efficiency is evaluated by a comparison with experimental results of model fluids casting in model formworks. KW - Fresh concrete (A) KW - Rheology (A) KW - Modeling (E) KW - Permeability (C) KW - Yield stress KW - Simulation KW - Flow of mortar KW - Flow of concrete PY - 2011 DO - https://doi.org/10.1016/j.cemconres.2011.01.013 SN - 0008-8846 SN - 1873-3948 VL - 41 IS - 5 SP - 496 EP - 503 PB - Pergamon Press CY - New York, NY AN - OPUS4-25532 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaenisch, Gerd-Rüdiger A1 - Deresch, Andreas A1 - Bellon, Carsten A1 - Ewert, Uwe A1 - Przybilla, Waldemar ED - Thompson, D.O. ED - Chimenti, D.E. T1 - Measurement and modeling of scatter ratios at high energies N2 - Determining scatter ratios at high energies (> ~ 1MeV) presents challenges not immediately obvious from measurements at conventional X-ray energies. This includes reduced attenuation even in heavy elements as well as a stronger forward bias of scattering. In order to check the reliability of different measurement setups with regard to material thicknesses, distances, and collimation, attenuation and scattering were separately simulated using a Monte Carlo model. The simulation results help in understanding the sources of radiation scattered into the detection area, thereby aiding in eliminating undesired contributions. T2 - 37th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - San Diego, CA, USA DA - 18.07.2010 KW - Radiography KW - Optimisation KW - X-ray detection KW - Simulation KW - High energy KW - Co-60 KW - Modeling KW - Scatter PY - 2011 SN - 978-0-7354-0888-3 DO - https://doi.org/10.1063/1.3591895 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1335 SP - 517 EP - 524 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-25358 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Österle, Werner A1 - Dmitriev, Andrey T1 - Functionality of conventional brake friction materials - Perceptions from findings observed at different length scales N2 - Automotive braking is based on dry friction between fixed pads and a rotating disc. Besides macroscopic thermo-physical properties, the development of topographic features on the mesoscopic scale and the nanostructure of the third body formed by wear processes, determine brake performance properties. Whereas modelling on the atomistic scale is suitable to understand mechanisms leading to nanocrystalline surface films, the properties of such films can be assessed best with a model based on movable cellular automata (MCA). It turned out that the presence of at least 10% of soft nanoinclusions is most essential in respect to smooth sliding conditions. It made no major difference whether graphite or copper particles were assumed as soft nanoinclusions. The third body material is not only the stuff which spreads over contact areas, but it also contributes to contact size by wear particle compaction and formation of secondary contact areas. The evolution of contact size is the major feature of mesoscopic modelling and thus it is capable to model and explain dynamic changes of the coefficient of friction (COF) during certain brake operations. Although it is still ambiguous in many cases which feature has the major impact on friction behaviour, the following conclusions can be drawn. The reinforcing ingredients of the pad material serve as primary contact sites and thus define the starting condition for mesoscopic simulations. A certain amount of wear is necessary to provide a third body which is capable to form secondary contact sites and friction layers screening the first body materials. The composition and nanostructure of the third body is important as well, because it determines the friction level and is responsible for smooth sliding conditions. KW - Nanostructure KW - Microstructure KW - Mesostructure KW - Macrostructure KW - Modelling KW - Simulation PY - 2011 DO - https://doi.org/10.1016/j.wear.2010.11.035 SN - 0043-1648 VL - 271 IS - 9-10 SP - 2198 EP - 2207 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-24177 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wehrstedt, Klaus-Dieter A1 - Malow, Marcus T1 - Letter to the Editor - Comments on the "Letter to the editor" by M.-L. You and C.-M. Shu (Journal of Thermal Analysis and Calorimetry, 2010;100:367-369) as response to the "Letter to the editor" by M. Malow and K.-D. Wehrstedt (Journal of Thermal Analysis and Calorimetry, 2009;98:885-886) KW - Dilauroyl peroxide KW - Oxygen balance KW - DSC KW - Simulation KW - SADT PY - 2011 DO - https://doi.org/10.1007/s10973-010-1122-0 SN - 1388-6150 SN - 1418-2874 SN - 0368-4466 SN - 1572-8943 VL - 103 IS - 1 SP - 409 EP - 410 PB - Kluwer Academic Publ. CY - Dordrecht AN - OPUS4-23210 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaenisch, Gerd-Rüdiger A1 - Bellon, Carsten A1 - Schumm, A. A1 - Tabary, J. A1 - Duvauchelle, P. ED - Thompson, D.O. ED - Chimenti, D.E. T1 - Radiographic benchmark problem 2009 - scatter calculations in modelling T2 - 36th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Kingston, RI, USA DA - 2009-07-26 KW - Radiography KW - Justifications or modifications of Monte Carlo methods KW - Emission KW - Absorption and scattering of electromagnetic radiation KW - X-ray scattering KW - Simulation KW - Röntgenspektrum Benchmark KW - Monte Carlo Modell PY - 2010 SN - 978-0-7354-0748-0 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 1211 SP - 2117 EP - 2124 CY - Melville, NY AN - OPUS4-21137 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Deresch, Andreas A1 - Jaenisch, Gerd-Rüdiger A1 - Bellon, Carsten A1 - Warrikhoff, A. ED - Thompson, D.O. ED - Chimenti, D.E. T1 - Simulation and experimental verification of X-ray spectra T2 - 36th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Kingston, RI, USA DA - 2009-07-26 KW - X-ray KW - Spectrum KW - Simulation KW - Röntgenspektrum KW - Dekonvolution PY - 2010 SN - 978-0-7354-0748-0 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 1211 SP - 535 EP - 540 CY - Melville, NY AN - OPUS4-21136 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zhukovskiy, M. A1 - Skachkov, M. A1 - Deresch, Andreas A1 - Jaenisch, Gerd-Rüdiger A1 - Bellon, Carsten ED - Thompson, D.O. ED - Chimenti, D.E. T1 - Simulation of electron transport T2 - 36th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Kingston, RI, USA DA - 2009-07-26 KW - Electron transport KW - Monte Carlo method KW - Stopping power KW - Simulation KW - Elektronentransport PY - 2010 SN - 978-0-7354-0748-0 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 1211 SP - 572 EP - 578 CY - Melville, NY AN - OPUS4-21134 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dmitriev, Andrey A1 - Österle, Werner T1 - Modeling of brake pad-disc interface with emphasis to dynamics and deformation of structures N2 - The frictional behavior at local contacts in an automotive brake system was analysed on the basis of computer simulation by movable cellular automata method. The boundary conditions of the model were adjusted to experimental observations obtained by TEM. The model proved to be adequate for simulating mechanical mixing and velocity accommodation at the pad-disc interface. Dynamics of particle interaction were visualized by showing rotation angles and velocity vectors. The model provided information on the development of plastic deformation for metal-on-metal contacts and on crack formation at graphite lamellae of cast iron disc. Results are in agreement with conventional friction theories. KW - Nanotribology KW - Pad-disc interface KW - Simulation KW - Mechanically mixed layer PY - 2010 DO - https://doi.org/10.1016/j.triboint.2009.10.012 SN - 0301-679X VL - 43 IS - 4 SP - 719 EP - 727 PB - Butterworth-Heinemann CY - Oxford AN - OPUS4-20876 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Babu, S. S. A1 - Sonnenberg, G. A1 - Schwenk, Christopher A1 - Goldak, J. A1 - Porzner, H. A1 - Khurana, S.P. A1 - Zhang, W. A1 - Gayler, J. T1 - How can computational weld mechanics help industry? KW - Schweißen KW - Simulation KW - Temperatur KW - Verzug KW - Eigenspannungen PY - 2010 SN - 0043-2296 SN - 0096-7629 VL - 89 IS - 1 SP - 40 EP - 45 PB - American Welding Society CY - New York, NY AN - OPUS4-20793 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaenisch, Gerd-Rüdiger A1 - Bellon, Carsten A1 - Schumm, A. A1 - Tabary, J. A1 - Duvauchelle, P. ED - Thompson, D. O. ED - Chimenti, D. E. T1 - A proposed benchmark problem for scatter calculations in radiographic modelling T2 - 35th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Chicago, IL, USA DA - 2008-07-20 KW - Radiography KW - Justifications or modifications of Monte Carlo methods KW - Emission KW - Absorption, and scattering of electromagnetic radiation KW - X-ray scattering KW - Radiographie KW - Simulation KW - Benchmark KW - Monte Carlo Verfahren KW - Streustrahlung PY - 2009 SN - 978-0-7354-0629-2 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1096 SP - 1930 EP - 1937 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-20134 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Habib, Abdel Karim A1 - Schalau, Bernd A1 - Acikalin, Hatice Aydan A1 - Steinbach, J. T1 - Transient calculation of the boundary layer flow over spills N2 - In this work, results of numerical simulations and experimental investigations of the mass flow from evaporating liquid pools are presented. Numerical simulations are based on the boundary layer equations combined with an algebraic turbulence model. The experiments were carried out on open air test sites within flat and very rough topographies, at different temperatures with ethanol and cyclohexane as the evaporating liquids. An experimental investigation of the influence of the topography on the evaporation of a liquid pool is conducted. The results of the simulation are validated against experimental data from the open air experiments. Furthermore, a comparison of the simulation results with empirical prediction models has been made. KW - Evaporation KW - Mass transfer KW - Modeling KW - Simulation PY - 2009 DO - https://doi.org/10.1002/ceat.200800527 SN - 0930-7516 SN - 1521-4125 VL - 32 IS - 2 SP - 306 EP - 311 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-18747 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kloß, Heinz A1 - Wäsche, Rolf T1 - Analytical approach for wear prediction of metallic and ceramic materials in tribological applications N2 - Wear mechanisms, as adhesion, abrasion, fatigue and tribochemical wear, are complex in their physical and chemical nature. A theoretical description and prediction of wear are in most cases still far from reality. It is, therefore, important to use test rigs before a practical application of a given material combination under tribological loading. On the other hand, model equations can be helpful for wear description, if a single wear mechanism is dominant. Under oscillating and continuous sliding contact conditions, equations for wear calculation are presented to describe running-in and stationary wear behaviour of metals and ceramics. By using shear energy density, real area of contact, flash temperature, activation energy and numerical simulations with the method of movable cellular automata (MCA), wear data were calculated and compared to experimental laboratory results. KW - Wear KW - Surface temperature KW - Activation energy KW - Simulation KW - Movable cellular automata (MCA) PY - 2009 DO - https://doi.org/10.1016/j.wear.2008.04.034 SN - 0043-1648 VL - 266 IS - 3-4 SP - 476 EP - 481 PB - Elsevier CY - Amsterdam AN - OPUS4-18651 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmitt, R. A1 - Koerfer, F. A1 - Sadowny, O. A1 - Zimmermann, J. A1 - Krüger-Sehm, R. A1 - Xu, M. A1 - Dziomba, T. A1 - Koenders, L. A1 - Goch, G. A1 - Tausendfreund, A. A1 - Patzelt, S. A1 - Simon, S. A1 - Rockstroh, L. A1 - Bellon, Carsten A1 - Staude, Andreas A1 - Woias, P. A1 - Goldschmidtböing, F. A1 - Rabold, M. T1 - Virtuelle Messgeräte - Definition und Stand der Entwicklung N2 - Die Mikro- und Nanotechnologie gehört zu den Schlüsseltechnologien des 21. Jahrhunderts mit hohen Wachstumsprognosen, wie auch die im Auftrag des BMBF durchgeführte Studie “Nanotechnologie als wirtschaftlicher Wachstumsmarkt” von 2004 ausführlich darstellt. Aus diesem Trend resultiert ein steigender Bedarf an Messsystemen, die Nanostrukturen prozessnah bzw. im Fertigungsprozess charakterisieren können. Virtuelle Messgeräte liefern Erkenntnisse zur Entwicklung neuartiger Messsysteme, Analyse und Optimierung bestehender Verfahren sowie die Bestimmung der Messunsicherheit und modellbasierten Korrektur systematischer Fehler. Der virtuelle Messprozess umfasst neben dem Messmittel auch die Probe und die Wechselwirkungen zwischen beiden. In diesem Beitrag werden virtuelle Messgeräte vorgestellt sowie deren Anwendung diskutiert. N2 - Micro- and nanotechnology experienced a high economic growth in recent years. This yields in a growing demand for measuring instruments which are closely linked to the production process. Virtual measuring instruments provide knowledge for the development of new systems, the analysis and optimization of established devices as well as the determination of the uncertainty in measurement. The virtual measuring process consists of the measuring instrument, the sample, and the interaction between both. In this article examples of current developments of virtual instruments are presented and their way of utilization is discussed. KW - Virtuelle Messtechnik KW - Simulation KW - Messunsicherheit KW - Virtual metrology KW - Measurement uncertainty PY - 2008 DO - https://doi.org/10.1524/teme.2008.0872 SN - 0340-837X SN - 0178-2312 SN - 0171-8096 VL - 75 IS - 5 SP - 298 EP - 310 PB - Oldenbourg CY - München AN - OPUS4-17569 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaenisch, Gerd-Rüdiger A1 - Bellon, Carsten A1 - Ewert, Uwe ED - Thompson, D. O. T1 - Reliability assessment by simulation for high energy radiography T2 - 33th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Portland, OR, USA DA - 2006-07-30 KW - Simulation KW - Radiography KW - CAD KW - Probability of Detection PY - 2007 SN - 978-0-7354-0399-4 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 894 SP - 1831 EP - 1838 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-15696 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wongpanya, Pornwasa A1 - Böllinghaus, Thomas A1 - Lothongkum, G. T1 - Effects of hydrogen removal heat treatment on residual stresses in high strength structural steel welds T2 - International Conference "Tubular structures" CY - Quebec, Canada DA - 2006-08-31 KW - Hydrogen KW - Simulation KW - High strenght structural steel KW - Restraint intensity KW - Heat treatment PY - 2006 UR - http://www.iiw-iis.org/ SN - 0043-2288 SN - 1878-6669 VL - 50 IS - Special Issue SP - 96 EP - 103 PB - Springer CY - Oxford AN - OPUS4-13932 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hünecke, Joachim A1 - Schöne, Dieter A1 - Klingbeil, Dietmar A1 - Bork, Claus-Peter T1 - Advanced life prediction by microstructural simulation of short cracks in a low carbon steel N2 - This paper deals with life prediction by observation and simulation of short fatigue cracks in cyclically loaded smooth and notched specimens made of 0.15 wt-% carbon steel SAE1017. The measured crack behaviour was simulated in a microstructural environment. Reference tests under constant amplitude loading allowed to determine model parameters and hence a reasonable life prediction by simulation resulted even for service loading. Short crack behaviour was a measurable property for damage also to compare smooth and notched specimens. KW - Short cracks KW - Life prediction KW - Simulation KW - Fatigue KW - Microstructure KW - Service loading KW - Notch KW - Kurze Risse KW - Gefüge KW - Ermüdung KW - Lebensdauer PY - 2006 DO - https://doi.org/10.1016/j.ijfatigue.2005.07.049 SN - 0142-1123 VL - 28 IS - 9 SP - 993 EP - 1000 PB - Elsevier CY - Oxford AN - OPUS4-12559 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, T. A1 - Kalinka, Gerhard A1 - Auer, C. A1 - Hinrichsen, G. T1 - Computer Simulation of Crystallization Kinetics in FIber-Reinforced Composites KW - Verbundwerkstoffe KW - Thermoplaste KW - Kristallisation KW - Kristallisationskinetik KW - Erstarrung KW - Avrami KW - Modellrechnung KW - Simulation PY - 1994 SN - 0021-8995 SN - 1097-4628 VL - 51 SP - 399 EP - 406 PB - Wiley InterScience CY - Hoboken, NJ AN - OPUS4-11992 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auer, C. A1 - Kalinka, Gerhard A1 - Krause, T. A1 - Hinrichsen, G. T1 - Crystallization Kinetics of Pure and Fiber-Reinforced Poly(phenylene Sulfide) KW - Verbundwerkstoffe KW - Thermoplaste KW - Kristallisation KW - Kristallisationskinetik KW - Erstarrung KW - Avrami KW - Modellrechnung KW - Simulation PY - 1994 SN - 0021-8995 SN - 1097-4628 VL - 51 SP - 407 EP - 413 PB - Wiley InterScience CY - Hoboken, NJ AN - OPUS4-11991 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane A1 - Brink, Arne A1 - Röllig, Mathias A1 - Wiggenhauser, Herbert A1 - Hillemeier, B. A1 - Rieck, C. T1 - Struktur- und Feuchteuntersuchung in Betonstrukturen mit der Impuls-Thermografie KW - Zerstörungsfreie Prüfung im Bauwesen KW - Impuls-Thermografie KW - Beton KW - Hohlstellen KW - Kiesnester KW - Simulation PY - 2003 UR - http://www3.interscience.wiley.com/cgi-bin/jtoc/60500216/2005 SN - 0171-5445 SN - 1437-0980 VL - 25 IS - 1 SP - 22 EP - 26 PB - Ernst CY - Berlin AN - OPUS4-3164 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bomas, H. A1 - Hünecke, Joachim A1 - Laue, S. A1 - Schöne, Dieter A1 - Mayr, P. T1 - Anrisslebensdauervorhersage am Beispiel glatter und gekerbter Proben des Werkstoffes Cm15 KW - Kurze Risse KW - Simulation KW - Kerben KW - Korngröße KW - Ermüdung PY - 2002 UR - http://www3.interscience.wiley.com/cgi-bin/fulltext/93520356/PDFSTART SN - 0933-5137 SN - 1521-4052 VL - 33 IS - 5 SP - 230 EP - 237 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-2520 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maierhofer, Christiane A1 - Brink, Arne A1 - Röllig, Mathias A1 - Wiggenhauser, Herbert T1 - Transient thermography for structural investigation of concrete and composites in the near surface region KW - Impulse thermography KW - Non-destructive testing KW - Quantitative analysis KW - Concrete KW - Composites KW - Civil engineering KW - Simulation KW - Finite differences PY - 2002 SN - 1350-4495 VL - 43 SP - 271 EP - 278 PB - Pergamon Press CY - Oxford AN - OPUS4-1759 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Holtappels, Kai A1 - Dietlen, Siegmund A1 - Schröder, Volkmar A1 - Brinkmann, Ch. A1 - Stickling, J. A1 - Schönbucher, A. T1 - Messung und Simulation des Inertgaseinflusses auf Explosionsgrenzen bei erhöhten Anfangsdrücken KW - Explosionsgrenzen KW - Druck KW - Experimentelles KW - Simulation KW - Inertgaseinfluß PY - 2001 SN - 0009-286X SN - 1522-2640 VL - 73 IS - 3 SP - 270 EP - 274 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-1103 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -