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 - Lubeseder, Christian A1 - Wurmb, Ingo von A1 - Meinhardt, Josef A1 - Wagner, Marcus A1 - Marburg, Steffen T1 - Vibration analysis of an automotive forming tool using coupled MBS-FEM simulation and experimental validation T2 - Proceedings of the 26th International Conference on Noise and Vibration Engineering (ISMA2014), Leuven, Belgium N2 - To improve efficiency in automotive press shops, press systems with increasingly high stroke rates are beingimplemented, raising thereby the structural dynamic load on the press and especially on the forming tool. Adetailed knowledge of the vibrations and resulting critical loads is thus essential for accurate and reliable de-signs of forming tools. In this paper, multibody simulation (MBS) of a selected automotive tool is presentedenabling the identification of the vibration of its components. Starting from a pure rigid modelling approach,the MBS model is extended by adding finite element (FE) component to allow extra flexibility in the sys-tem. As an example, a detailed vibrational analysis - both in time and frequency domain - is performed ona blankholder. Also an experimental validation of a blankholder vibration under operational load is carriedout, with test signal data gained by piezoelectric accelerometers. Y1 - 2014 UR - http://past.isma-isaac.be/downloads/isma2014/papers/isma2014_0245.pdf SP - 2931 EP - 2942 ER - TY - CHAP A1 - Swidergal, Krzysztof A1 - Lubeseder, Christian A1 - Wurmb, Ingo von A1 - Lipp, Arnulf A1 - Meinhardt, Josef A1 - Wagner, Marcus A1 - Marburg, Steffen T1 - Structural analysis of an automotive forming tool for large presses using LS-DYNA T2 - 10th European LS-DYNA Conference, Würzburg Y1 - 2015 ER - TY - CHAP A1 - Swidergal, Krzysztof A1 - Lubeseder, Christian A1 - Wurmb, Ingo von A1 - Meinhardt, Josef A1 - Wagner, Marcus A1 - Marburg, Steffen T1 - Effiziente Methode zur Bestimmung von dynamischen strukturellen Belastungen in Großpresswerkzeugen T2 - 36. EFB-Kolloquium Blechverarbeitung 2016, Fellbach Y1 - 2016 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 - Wagner, Marcus A1 - Franke, Markus A1 - Krause, Tom Janis A1 - Heinle, Ingo T1 - Data augmentation of material properties for machine learning in industrial production - a case study in an automotive press shop JF - Engineering Computations : International journal for computer-aided engineering and software N2 - In the context of industrial production, the utilisation of data recording and processing techniques is becoming increasingly prevalent across the manufacturing sector. The solutions integrate sensors, facilitate the transmission of data, and enable data-driven decision-making, thereby reducing downtime and optimising quality. However, challenges emerge due to the limited non-transferable data or models between processes. Alterations to the production process can render collected data invalid, resulting in restricted datasets and potential overfitting. To address these issues, techniques such as data augmentation are employed. This study aims to develop a data augmentation methodology applicable in dynamic, data-scarce production environments, enhancing the robustness of regressor predictions. KW - Data augmentation KW - Machine learning KW - Manufacturing KW - Deep drawing Y1 - 2025 U6 - https://doi.org/10.1108/EC-08-2024-0787 PB - Emerald Publishing CY - Leeds ER - TY - CHAP A1 - Stocker, Philipp A1 - Lehrer, Tobias A1 - Duddeck, Fabian A1 - Wagner, Marcus T1 - Face-wise prediction of sheet-metal drawability using graph neural networks T2 - Journal of Physics: Conference Series N2 - The early design phase of deep-drawn structural components involves time-consuming iterative development. Traditional drawability assessments rely on finite element simulations, which are computationally expensive and slow the design process. Alternative machine learning (ML) approaches show promise in accelerating this process but face challenges with existing methods. Existing low-dimensional ML models only provide global predictions without identifying specific geometric regions prone to failure. High-dimensional models provide local predictions but require significant amounts of training data. We propose a data-driven approach leveraging graph neural networks (GNNs) for face-wise drawability prediction of sheet metal components in their computer-aided design (CAD) representation. Our method aims to bridge the gap between the computational efficiency of ML and the spatial resolution of simulation by providing face-wise insight into potential failure regions. This study utilises a dataset of parametric U-channel geometries with variability in both geometry and topology. Ground-truth labels are generated using inverse analysis simulations. Geometric entities are represented through the use of UV parameterisations, whereby 3D surfaces are mapped into 2D space to facilitate geometric encoding. Concurrently, the topological relationships are captured using a face adjacency graph. To address data scarcity, we evaluate how different amounts of training data affect model performance and perform ablation studies to analyse the impact of different CAD representation features. Our results show that the proposed approach achieves high accuracy even with limited training data. In addition, the ablation studies provide insights into the most critical CAD features, guiding future research. These results highlight the potential of our GNN to predict face-wise drawability in the early design phase. Y1 - 2025 U6 - https://doi.org/10.1088/1742-6596/3104/1/012053 SN - 1742-6588 N1 - Corresponding author der OTH Regensburg: Philipp Stocker VL - 3104 IS - 1 PB - IOP Publishing ER - TY - JOUR A1 - Hollweck, Christoph A1 - Leidinger, Lukas A1 - Hartmann, Stefan A1 - Wagner, Marcus A1 - Wüchner, Roland T1 - An analysis of the critical time step size for explicit dynamics using trimmed B-splines, LR-splines, and THB-splines JF - Computer Methods in Applied Mechanics and Engineering N2 - Isogeometric analysis (IGA) combined with explicit dynamics is increasingly used in academia and has already been successfully applied in industrial simulations, including crash and sheet-metal forming. Since explicit schemes are only conditionally stable, accurate estimation of the critical time step is essential for both stability and efficiency. Adaptive mesh refinement is widely used to balance accuracy and computational cost. In IGA, THB- and LR-splines break the tensor-product structure of standard B-splines and enable local refinement, but their effect on the critical time step under trimming has not been systematically studied - a key requirement for reliable time step estimation. We investigate the critical time step in explicit dynamic simulations using trimmed B-splines, LR-splines, and THB-splines, based on a lumped mass matrix obtained by simple row summation. One-dimensional bar, two-dimensional membrane, and trimmed shell models are analyzed to determine how trimming and local refinement influence element and system eigenfrequencies, which directly control the stable time step. Refined boundary elements in open knot vectors are identified as the main bottleneck. Trimming these elements can increase the stable time step, though certain trimming configurations introduce new restrictions. Results show that LR- and THB-splines impose time step constraints similar to B-splines, making them equally suitable for explicit simulations. We also present a general method for computing element-wise Bézier extraction operators for LR- and THB-splines, enabling straightforward integration into standard finite element solvers. The findings are validated through nonlinear sheet-metal forming simulations in LS-DYNA using shells discretized with trimmed B-, LR-, and THB-splines. This represents the first such application and demonstrates their practical feasibility for industrial use. Y1 - 2026 U6 - https://doi.org/10.1016/j.cma.2025.118656 SN - 0045-7825 N1 - Corresponding author der OTH Regensburg: Christoph Hollweck VL - 450 PB - Elsevier ER - TY - INPR A1 - Lehrer, Tobias A1 - Stocker, Philipp A1 - Duddeck, Fabian A1 - Wagner, Marcus T1 - UCSM: Dataset of U-Shaped Parametric CAD Geometries and Real-World Sheet Metal Meshes for Deep Drawing N2 - The development of machine learning (ML) applications in deep drawing is hindered by limited data availability and the absence of open-access benchmarks for validating novel approaches, including domain generalization over distinct geometries. This paper addresses these challenges by introducing a comprehensive U-shaped dataset tailored to this manufacturing process. Our U-Channel sheet metal (UCSM) dataset combines 90 real-world meshes with an infinite number of synthetic geometry samples generated from four parametric Computer-Aided Design (CAD) models, ensuring extensive geometry variety and data quantity. Additionally, a ready-to-use dataset for drawability assessment and segmentation is provided. Leveraging CAD and mesh data sources bridges the gap between sparse data availability and ML requirements. Our analysis demonstrates that the proposed parametric models are geometrically valid, and real-world and synthetic data complement each other effectively, providing robust support for ML model development. While the dataset is confined to U-shaped, thin-walled, deep drawing scenarios, it considerably aids in overcoming data scarcity. Thereby, it facilitates the validation and comparison of new geometry-generalizing ML methodologies in this domain. By providing this benchmark dataset, we enhance the comparability and validation of emerging methods for ML advancements in sheet metal forming. Y1 - 2025 U6 - https://doi.org/10.2139/ssrn.5268323 N1 - Zugehöriges Datenset: https://doi.org/10.5281/zenodo.15327950 PB - SSRN ER - TY - JOUR A1 - Sittl, Christopher A1 - Marburg, Steffen A1 - Deckers, Elke A1 - Wagner, Marcus T1 - Model order reduction for unbounded second-order vibroacoustic systems using infinite elements and Dirichlet-to-Neumann map JF - Computer Methods in Applied Mechanics and Engineering N2 - This work addresses the efficient numerical simulation of time-harmonic vibroacoustic problems in unbounded domains, with a focus on fluid-structure interaction. The underlying mathematical model is a second-order dynamical system arising from the coupling of structural and acoustic domains, incorporating material damping effects, relevant in structural acoustics and noise control applications. A central novelty of the proposed method is its unified computational framework that supports two distinct strategies for treating unbounded fluid domains: (1) non-local absorbing boundary conditions based on Dirichlet-to-Neumann map, and (2) infinite elements, which extend the computational domain rather than truncate it. Both approaches are integrated into a consistent formulation that enables flexible and accurate modeling of exterior wave propagation. To efficiently evaluate frequency-domain transfer functions, the method employs model order reduction using the Padé-via-Lanczos technique. While this algorithm typically targets first-order systems, the present approach uses a Schur complement strategy to reduce the second-order system in a way that maintains computational efficiency and storage requirements comparable to first-order formulations. Importantly, the framework seamlessly embeds both interior structural damping and the additional dissipation introduced by the acoustic-domain truncation into the model-order reduction process. The exterior acoustic field is represented via spherical harmonic expansions, with expansion coefficients computed from the reduced system. Numerical results demonstrate the method’s accuracy, efficiency, and scalability, making it well-suited for high-fidelity vibroacoustic analysis in unbounded domains. KW - Lanczos algorithm KW - Krylov-subspace projection KW - Dirichlet-to-Neumann map KW - Infinite elements KW - Padé approximation KW - Fluid-structure interaction KW - Acoustics KW - Spherical harmonics Y1 - 2026 U6 - https://doi.org/10.1016/j.cma.2026.118846 VL - 453 PB - Elsevier ER - TY - GEN A1 - Lehrer, Tobias A1 - Stocker, Philipp A1 - Duddeck, Fabian A1 - Wagner, Marcus T1 - Parametric CAD Models to Create an Infinite Number of Structural U-Shaped Sheet Metal Geometries [Data set] N2 - The U-Channel Software is a python package containing four parametric models of U-shaped Sheet metals. The parameters refer to geometric dimensions, angles, fillet radii. Using the models, one can generate an infinite number of U-shaped sheet metal geometries, e.g. as STEP files. The parametric models are inspired by real-world shapes. A feasibility check is provided to ensure plausiblity of the shapes. Further features of the code are creating images of the geometries and generating geometries and images in parallel. For more details, refer to the repository and associated publications. Y1 - 2024 U6 - https://doi.org/10.5281/ZENODO.14191374 N1 - Repository URL: https://github.com/ToLe814/uchannel Programming language: Python Development Status: Active ER -