Microstructure-informed ICME framework for laser-assisted flange forming of S700 steel
International Journal of Mechanical Sciences, pp. 112212
Abstract
In multi-step sheet metal forming, the deformation and damage state inherited from upstream operations can govern failure during subsequent processing. Conventional process-chain simulations commonly transfer macroscopic quantities such as equivalent plastic strain, which do not uniquely represent the underlying microstructural state. This work presents an Integrated Computational Materials Engineering (ICME) framework for laser-assisted flange forming of S700MC steel, sequentially coupling shear cutting, localized laser heating, and flange forming through deterministic transfer of dislocation densities and void fraction as microstructural state variables (MSV) using a damage-integrated thermo-micro-mechanical (D-TMM) formulation. A circumferential binning procedure is introduced to quantify spatial variations of each field along the flange edge. The simulations reveal persistent damage localization near 35° and 70°, robust to circumferential discretization, evaluation-region height, and removal of one symmetry plane. A conventional formulation transferring equivalent plastic strain and void fraction predicts higher mean plastic strain but does not reproduce this localization. D-TMM control simulations show that the shear-sensitive damage contribution is required for the angular damage pattern, while transferred MSVs increase its severity. Increasing the forming-zone temperature from approximately 350°C to 550°C reduces numerical fracture by about 72%, while blank inversion yields an overall reduction of about 85% relative to the 350°C condition. Representative experiments support the predicted response through forming-force and flange-thickness comparisons. The mean grain aspect ratio decreases from 4.55 to 2.47 from cold to laser-assisted forming, while simulated wall-immobile dislocation densities are of the same order of magnitude as EBSD-derived GND densities, differing by approximately a factor of 1.4. The framework therefore provides a microstructure-informed basis for assessing edge fracture in sequential forming processes.
Authors 7
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Affiliation as printed
RWTH Aachen University, IEHK Steel Institute, Intzestrasse 1, Aachen, D-52072, Germany
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Fraunhofer Institute for Production Technology IPT
Affiliation as printed
Fraunhofer Institute for Production Technology IPT, Steinbachstrasse 17, Aachen, D-52074, Germany
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Affiliation as printed
RWTH Aachen University, IEHK Steel Institute, Intzestrasse 1, Aachen, D-52072, Germany
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Fraunhofer Institute for Production Technology IPT
Affiliation as printed
Fraunhofer Institute for Production Technology IPT, Steinbachstrasse 17, Aachen, D-52074, Germany
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Affiliation as printed
TU Berlin, Chair Materials for Additive Manufacturing, Ernst-Reuter-Platz 1, Berlin, D-10587, Germany
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Christian Brecher Aachen Fraunhofer Institute for Production Technology IPT Laboratory for Machine Tools and Production Engineering WZL
RWTH Aachen University · Fraunhofer Institute for Production Technology IPT
Affiliation as printed
Fraunhofer Institute for Production Technology IPT, Steinbachstrasse 17, Aachen, D-52074, Germany
RWTH Aachen University, Laboratory for Machine Tools and Production Engineering WZL, Campus-Boulevard 30, Aachen, D-52074, Germany
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Affiliation as printed
RWTH Aachen University, IEHK Steel Institute, Intzestrasse 1, Aachen, D-52072, Germany