Validation of material models for sheet metals using an innovative tool
Final Report Abstract
The project examined the application of the finite element method (FEM) in the process design of sheet metal forming, with a particular focus on the validation of material models. The constitutive model employed and the influence of the process play a pivotal role in the precision of the FEM results. A crucial element of these models is the kinematic strain hardening that occurs when the sheet metal advances into the forming area. To validate the constitutive models, the MUC test (Material Under Control) is utilized, a methodology developed in this research project for evaluating material behavior under authentic conditions. A comprehensive investigation was conducted to ascertain the influence of numerical, process-related, and model-dependent parameters on the test outcomes. The validation method developed in this research project was applied to three different materials representing disparate material classes: the micro-alloyed steel HC340LA, the dual-phase steel DP590HD, and the aluminum alloy AA5754. Moreover, disparate material models derived from a unified database were evaluated for the DP590HD, thereby illustrating the potential for identifying suitable material models for particular requirements. Ultimately, equivalent material models based on disparate calibration strategies were evaluated. In this project, the MUC-Test was also expanded to encompass an upstream forming process phase, thereby creating more realistic conditions through load cycling. To this end, sheet metal samples were produced in three distinct pre-deformation states: uniaxial, plane strain, and biaxial. Subsequently, an extended MUC-Test with complex, non-linear strain paths was conducted to create a database for a validation experiment. The simulations of the digital twin employed constitutive models that, for instance, incorporated the kinematic hardening parameters of the Chaboche-Rousselier model. The outcomes of the simulations were contrasted with the force-displacement signals, in addition to the major- and minor strains calculated by a digital image correlation system (DIC). The significance of the findings of this project lies in the enhancement of the precision of finite element (FEM) simulations in sheet metal forming and the development of a validation experiment that is not dominated by friction, such as the cross-cup experiment, and still represents a complex strain distribution. By incorporating kinematic hardening and realistic pre-deformation conditions into the constitutive models, their validation by actual forming processes can be enhanced. This results in more precise simulations and enables a more efficient design of sheet metal forming processes, which in turn improves the quality of the manufactured parts and may reduce the costs of industrial production.
Publications
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Potentials for material card validation using an innovative tool. IOP Conference Series: Materials Science and Engineering, 1157(1), 012067.
Eder, M.; Gruber, M.; Manopulo, N. & Volk, W.
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Potentials for Material Card Validation Using an Innovative Tool, W Volk et al., 2022, The 12th International Conference and Workshop on Numerical Simulation of 3D Sheet Metal Forming Processes (NUMISHEET 2022)
W. Volk et al.
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Validation of material models for sheet metals using new test equipment. International Journal of Material Forming, 15(5).
Eder, Matthias; Gruber, Maximilian & Volk, Wolfram
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Innovative experimental setup for the investigation of material models with regard to strain hardening behavior. IOP Conference Series: Materials Science and Engineering, 1284(1), 012071.
Maier, L.; Eder, M.; Norz, R. & Volk, W.
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MUC-Test for the Investigation of Multi-Directional Strain Hardening Behavior for Alloy Sheets, L Maier et al, 2023, Forming Technology Forum Technical Meeting 2023
L. Maier et al.
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A Scientific Benchmark for Elasto-Plastic Constitutive Modeling - Part I: Micro- and Macroscopic Experimental Data Set and Benchmark Problem, L Maier et al, 2024, Open-Access
L. Maier et al.
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Investigations of strain rate sensitivity under different stress triaxialities for DC04. Materials Research Proceedings, 41, 2124-2133. Materials Research Forum LLC.
MAIER, Lorenz
