TY - CHAP A1 - Thumann, Philipp A1 - Swidergal, Krzysztof A1 - Wagner, Marcus T1 - Calculation and validation of material tests with specimens made out of filled elastomers T2 - 10th European LS-DYNA Conference 2015, Würzburg N2 - In deep-drawing dies for steel sheet parts of car bodies huge masses are moved. To prevent vibrations, which occur by sudden acceleration or stopping of those masses, elastomeric tubular dampers [1] are used. The dampers are made out of carbon filled elastomers. A good knowledge about the material behaviour of metals is available. But for the numerical investigation of complete deep-drawing dies the elastomeric dampers must be taken into account, too. To characterize the material behaviour of the elastomers tensile tests and pressure tests were carried out. The received material data from the tests were read into LS-DYNA [2]. Simulation models of the tensile test and the pressure test were created for LS-DYNA according to the real dimensions and boundary conditions. For validation purposes, calculations of loading cycles were done to enable a comparison between test data and simulation results. For the calculations the implemented material model *MAT_SIMPLIFIED_RUBBER_WITH_DAMAGE (*MAT_183) was used. The comparison shows a good fitting between the test data and the calculation results with respect to the mechanical material behaviour by using this material model in single loading cases. The settings from the simulations of material tests were transferred to simulations of dampers, which are used in deep-drawing dies. Y1 - 2015 UR - https://www.semanticscholar.org/paper/Calculation-and-validation-of-material-tests-with-Thumann-Swidergal/7502f1c70a07654c8238f4a6bd436aa5bd4c051f ER - TY - JOUR A1 - Sittl, Christopher A1 - Marburg, Steffen A1 - Wagner, Marcus T1 - Application of a Krylov subspace method for an efficient solution of acoustic transfer functions JF - Mechanical Systems and Signal Processing N2 - Solving acoustic radiation problems, arising from systems including fluid–structure interaction, is of interest in many engineering applications. Computing frequency response functions over a large frequency range is a concern in such applications. A method which solves the Helmholtz equation for multiple frequencies in one step is the matrix-Padé-via-Lanczos connection for unsymmetric systems, as presented by Wagner et al. [1]. The present work is based on Ref. [1] and presents a method for efficiently computing frequency responses over a frequency range for coupled structural-acoustic problems, where the structure and the acoustic near field are discretized with finite elements and an analytical Dirichlet-to-Neumann map approximates the far field. The method is based on a Krylov-subspace projection technique which derives a matrix-valued Padé approximation for a restricted area in the near field and the pressure field on a spherical boundary. On the spherical boundary, where the finite domain is truncated, the non-local modified Dirichlet-to-Neumann operator is applied as a low-rank update matrix. The present contribution extends this method and incorporates new techniques for a more stable model reduction through the Lanczos algorithm and a novel weighted adaptive windowing technique. Further, structural damping is incorporated, for computing the acoustic radiation of a harmonically excited plate. These computed results are compared with acoustic measurements in an anechoic chamber and verified with computational results obtained with a commercial code that uses the perfectly matched layer method. KW - Lanczos algorithm KW - Krylov-subspace projection KW - Dirichlet-to-Neumann map KW - Padé approximation KW - Fluid–structure interaction KW - Acoustics Y1 - 2021 U6 - https://doi.org/10.1016/j.ymssp.2020.107135 VL - 148 PB - Elsevier ER - TY - CHAP A1 - Swidergal, Krzysztof A1 - Wagner, Marcus A1 - Lubeseder, Christian A1 - Wurmb, Ingo von A1 - Meinhardt, Josef A1 - Marburg, Steffen T1 - Finite element simulation of blankholder’s lift-off in a deep drawing tool using Abaqus/Standard T2 - SIMULIA Community Conference, 19 - 21 May 2015, Berlin, Germany N2 - In the deep drawing tools for forming car body parts, heavy blankholders are used to prevent buckling and wrinkling of the blank. During each press cycle, those large masses need to be lifted, raising thereby the structural dynamic load on the deep drawing tool and on the press. Therefore a detailed knowledge about the blankholder’s lift-off event is essential for an accurate and robust design of forming tools. In this paper, a dynamic finite element method (FEM) simulation of a blankholder’s lift-off in a selected automotive deep drawing tool is presented enabling identification of regions of critical stresses. The FEM model is built within the Abaqus/CAE environment and solved with Abaqus/Standard. Each dynamic analysis is preceded by a static analysis where the gravity load is applied and the lifting bolts are pre-stressed. A special emphasis is put on modeling the elastomer dampers, which are installed between lifting bolts and the blankholder to avoid hard impacts during the lift-off event. Those dampers are modelled using a hyperelastic material with hysteresis. In addition, an experimental validation of a blankholder’s vibration under operating loading was carried out. The simulation results are in good agreement with the measurements. Y1 - 2015 UR - https://www.semanticscholar.org/paper/Final-Element-Simulation-of-Blankholder-'-s-in-a-%2F-Swidergal-Wagner/8398357757311fc364e3b942cc92c8c0a5f216bc ER - TY - CHAP A1 - Swidergal, Krzysztof A1 - Thumann, Philipp A1 - Lubeseder, Christian A1 - Wurmb, Ingo von A1 - Meinhardt, Josef A1 - Wagner, Marcus A1 - Marburg, Steffen T1 - Modeling and simulation of carbon black filled elastomer damper using LS-DYNA T2 - LS-DYNA Forum 2014, Bamberg Y1 - 2014 ER - TY - JOUR A1 - Thumann, Philipp A1 - Marburg, Steffen A1 - Meinhardt, Josef A1 - Saubiez, Jean‐Marc A1 - Hoogen, Michael A1 - Suck, Bertram A1 - Wagner, Marcus T1 - Frequency Dependent Fatigue Strength Investigations on Tempered Steel and Nodular Cast Iron JF - steel research international N2 - This paper presents experimental fatigue tests on specially shaped specimens made from quenched and tempered steel 42CrMoS4 and nodular cast iron EN-GJS-600-3. The specimens are geometrically designed to resemble actual subcomponents of forming and cutting dies for sheet metal manufacturing. These subcomponents have failed in the past.Experiments are carried out using a fictive load-time function, which is a modification of an actually measured load curve and has variable mean and amplitude values. This first test series serves as a general validation of a subsequent fatigue analysis. A second test series is carried out with constant mean and amplitude values with a load ratio 𝑅≈0. Here, the load frequencies in the individual test runs are varied between f = 5 Hz and f = 45 Hz in order to investigate the influence of the frequency. Both series are performed on a servo-hydraulic testing machine.The experimental data is then statistically evaluated. The values for the scatter correlate with data from the literature. The data from the test series with the fictive load-time function can thus be used for subsequent validation of a fatigue calculation, which will be addressed in a future publication. Most significant are the findings from the second series of experiments with varied load frequencies, as a significant frequency influence could be detected. Furthermore, the hardening and softening behavior under cyclic loading and the fracture behavior of the materials are analyzed and compared with data from the literature. KW - cast iron KW - fatigue analysis KW - fatigue strength KW - frequency dependence KW - materials testing KW - tempering steel Y1 - 2019 U6 - https://doi.org/10.1002/srin.201800620 VL - 90 IS - 7 PB - Wiley ER - TY - JOUR A1 - Swidergal, Krzysztof A1 - Lubeseder, Christian A1 - Wurmb, Ingo von A1 - Lipp, Arnulf A1 - Meinhardt, Josef A1 - Wagner, Marcus A1 - Marburg, Steffen T1 - Experimental and numerical investigation of blankholder’s vibration in a forming tool BT - a coupled MBS-FEM approach JF - Production Engineering - Research and Development N2 - In order to achieve the energy and efficiency goals in modern automotive press shops, press systems with increasingly high stroke rates are being implemented (Meinhardt in proceedings of ACI forming in car body engineering. Bad Nauheim, Germany 2012). As a side effect, the structural dynamic loads on the press and especially on the forming tool increase. Hence, to design reliable and withstanding forming tools, a detailed knowledge of the vibrations and resulting critical loads is essential. In this paper, the main focus is put on the vibration of the blankholder—the heaviest moving component in the forming tool. To predict those vibrations, a coupled multibody-finite element simulation (MBS-FEM) is conducted, which combines rigid and elastic modeling approaches. Also, an experimental validation of the blankholder vibration under operational load is carried out. To compare the numerical and experimental results—both in time and frequency domain—an 1/3-octave analysis of a blankholder’s vibrational speed is performed. The test measurements agree well with the MBS-FEM simulation. KW - Forming tool/die KW - Coupled MBS-FEM simulation KW - Blankholder KW - Vibration KW - Servo press Y1 - 2015 U6 - https://doi.org/10.1007/s11740-015-0640-9 SN - 0944-6524 VL - 9 IS - 5-6 SP - 634 PB - Springer ER - TY - CHAP A1 - Thumann, Philipp A1 - Wagner, Marcus A1 - Suck, Bertram A1 - Meinhardt, Josef A1 - Marburg, Steffen T1 - Explicit and Implicit FE Simulations of Material Tests for Subsequent Durability Analyses T2 - 11th European LS-DYNA Conference, Salzburg N2 - Because of increased stroke rates the loads on forming tools increase too. To ensure a save design of components, durability analyses are intended. For this, simulation results from FE analyses are necessary. Therefore, it is desirable to use elements with quadratic function, because of a good stress approximation.The goal of the described investigation is to show if calculation results created by LS-DYNA [1] can be used for durability analyses. Especially the use of quadratic elements is investigated. For the evaluation, on the one hand explicit FE analyses of a special durability test are carried out. These analyses are validated by available test data. To create results for later durability analyses further FE analyses with implicit time discretisation are carried out. In this paper results of the investigations are presented and evaluated critically. Y1 - 2017 UR - https://www.dynalook.com/conferences/11th-european-ls-dyna-conference/experiments-and-parameter-optimization/explicit-and-implicit-fe-simulations-of-material-tests-for-subsequent-durability-analyses ER - TY - CHAP A1 - Wegh, Niels A1 - Wagner, Marcus A1 - Gaudlitz, Daniel A1 - Finckh, Hermann A1 - Klein, Markus T1 - Numerical Simulation of Filling Process in Resin Transfer Molding T2 - 13th International Conference on Flow Processes in Composites Materials (FPCM-13), Kyoto, Japan Y1 - 2016 UR - https://www.fose1.plymouth.ac.uk/sme/fpcm/fpcm13/Abstracts/FPCM-13_extended_abstract_21.pdf ER - TY - RPRT A1 - Hederer, Sebastian A1 - Wagner, Marcus ED - Baier, Wolfgang T1 - Entwicklung und Implementierung eines konstitutiven Modells zur Beschreibung der Plastizität von Dualphasenstähle bei großen plastischen Deformationen T2 - Forschungsbericht 2018 / Ostbayerische Technische Hochschule Regensburg Y1 - 2018 UR - https://doi.org/10.35096/othr/pub-1382 SN - 9783981820911 SP - 68 EP - 69 ER - TY - CHAP A1 - Meckl, D. A1 - Lubeseder, Christian A1 - Zausinger, C. A1 - Wurmb, Ingo von A1 - Meinhardt, Josef A1 - Swidergal, Krzysztof A1 - Wagner, Marcus T1 - Simulation of press dies for large presses using the flexible multibody dynamics in Recurdyn T2 - 4th RecurDyn TechnologyDays 2014, München Y1 - 2014 ER -