07 Fakultät Konstruktions-, Produktions- und Fahrzeugtechnik

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    Local laser heat treatment of AlSi10Mg as-built parts produced by Laser Powder Bed Fusion
    (2024) Kramer, Steffen; Jarwitz, Michael; Schulze, Volker; Zanger, Frederik
    Today, complex structural components for lightweight applications are frequently manufactured by laser powder bed fusion (PBF-LB), often using aluminum alloys such as AlSi10Mg. However, the application of cyclic load cases can be challenging as PBF-LB produced AlSi10Mg parts typically have low ductility and corresponding brittle failure behavior in the as-built condition. Therefore, this paper presents investigations on the feasibility of a laser heat treatment of PBF-LB produced AlSi10Mg parts to locally increase the ductility and decrease the hardness in critical areas. Potential heat treatment process parameters were derived theoretically based on the temperature fields in the material calculated assuming three-dimensional heat conduction and a moving heat source. PBF-LB produced specimens were then laser heat treated at varying laser power and scan speed. Hardness measurements on metallographic cross sections showed hardness reductions of over 35 % without inducing hydrogen pore growth.
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    Stream finishing of additively manufactured AlSi10Mg PBF-LB parts: influence on surface quality and fatigue behaviour
    (2024) Wexel, Helena; Kramer, Steffen; Schubert, Johannes; Schulze, Volker; Zanger, Frederik
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    Towards learning human-seat interactions for optimally controlled multibody models to generate realistic occupant motion
    (2023) Fahse, Niklas; Harant, Monika; Roller, Michael; Kempter, Fabian; Obentheuer, Marius; Linn, Joachim; Fehr, Jörg
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    Inverse fuzzy arithmetic for the quality assessment of substructured models
    (2015) Iroz, Igor; Carvajal, Sergio; Hanss, Michael; Eberhard, Peter
    The dynamical analysis of complex structures often suffers from large computational efforts, so that the application of substructuring methods has gained increasing importance in the last years. Substructuring enables dividing large finite element models and reducing the resulting multiple bodies, yielding a reduction of, in this case, complex eigenvalue calculation time. This method is used to predict the appearance of friction-induced vibrations such as squeal in brake systems. Since the method is very sensitive to changes in parameter values, uncertainties influencing the results are included and identified. As uncertain parameters, standard coupling elements are considered and modeled by so-called fuzzy numbers, which are particularly well suited to represent epis- temic uncertainties of modeled physical phenomena. The influence of these uncertainties is transferred to undamped and damped eigenfrequencies of a substructured model by means of direct fuzzy analyses. An inverse fuzzy arithmetical approach is applied to identify the uncertain parameters that optimally cover the undamped reference eigenfrequencies of a non-substructured, full model. If a validity criteria is defined, a positive decision in favor of the most adequate model can be performed.
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    Comparison of driver models for powertrain test benches using a digital twin
    (2023) Schilling, Jannes; Wilmsen, Jan-Michael; Nitschke, Paul; Reuss, Hans-Christian
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    Finite element simulations of motorcyclist interaction with a novel passive safety concept for motorcycles
    (2021) Maier, Steffen; Doléac, Laurent; Hertneck, Holger; Stahlschmidt, Sebastian; Fehr, Jörg
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    Challenges of using augmented reality to support an efficient and error-free assembly in complex variant environments
    (2023) Dausch, Valesko; Roth, Daniel; Kreimeyer, Matthias; Bohr, Sebastian
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    Evaluation of a novel passive safety concept for motorcycles with combined multi-body and finite element simulations
    (2020) Maier, Steffen; Doléac, Laurent; Hertneck, Holger; Stahlschmidt, Sebastian; Fehr, Jörg
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    Simulation of a high-speed maglev train on an elastic guideway of infinite length
    (2022) Schneider, Georg; Schmid, Patrick; Kargl, Arnim; Liang, Xin; Dignath, Florian; Eberhard, Peter
    Simulations of the coupled vehicle/guideway dynamics are an essential part in the development of high-speed magnetic levitation (maglev) systems with higher speed than traveled so far. In this contribution, a two-dimensional rigid multibody model mapping the heave-pitch motion of the vehicle is presented and used for dynamics simulations of the vehicle traveling along an infinite elastic guideway. The concept of moving system boundaries is applied for the guideway model to efficiently implement an infinite series of elastic Euler-Bernoulli beams while keeping the number of system states small. Guideway deflection interpolation and computation of equivalent nodal forces and torques are realized using Hermite polynomials. Together with a physically advanced magnet model and a model predictive control scheme, the coupled system is applied for vehicle and guideway dynamics analysis for different vehicle speeds and guideway elasticities.