ICAMS / Interdisciplinary Centre for Advanced Materials Simulation

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A micromechanical modeling scheme to parameterize a loading-path- dependent hardening model for DC06 steel

Date: 18.07.2018
Time: 02:00 p.m.
Place: 18th International Conference on the Strength of Materials, Ohio, USA

Napat Vajragupta
Srinivas Kamath
Till Clausmeyer
Alexander Hartmaier

Computer-based simulations are accepted as tools to enhance metal forming processes. In this context, the material modeling becomes crucial, because it must be able to reflect the mechanical behavior of a material. A recent material model is adapted to consider hardening after loading-path-changes. The macroscopic model is capable to account for such phenomena as the Bauschinger effect and cross hardening, which affect metal forming processes. Conceptually such behavior is obtained by changes in the yield surface resulting in isotropic, kinematic and cross hardening. Despite a successful implementation of this loading-path dependent hardening model along with the experimental guidelines to determine material parameters, the relationship between such macroscopic model and important microstructural features is not directly formulated. Such constraint is a great obstacle for material development and microstructure design, because microstructural morphology governs the deformation mechanism of materials. Hence, the micromechanical modeling approach that considers important microstructural features could become an effective solution to this missing link. This study proposes a micromechanical modeling scheme to parameterize a loading-path-dependent hardening model for DC06 steel sheet. First, a microstructure model of DC06 steel is generated using an advanced dynamic microstructure generator (ADMG), which combines a particle simulation method with radical Voronoi tessellation to construct proper grain size and orientation distributions. Finite element simulations assuming the non-local crystal plasticity model for the individual grains of the microstructure are then conducted for various loading conditions including shear and reverse shear. In these simulations, crystal plasticity parameters are adapted to match the experiments. Afterwards, tension-shear condition is applied to the parameterized microstructure model whereas the homogenized model response serves as input for determining macroscopic material parameters. The parameterized model is validated for different tension-shear loading paths. Finally, the influence of microstructural features on deformation under tension-compression test is also studied.

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