Abstract

Polycrystalline metallic materials are essential components in modern automotive and aircraft industries (e.g., high-performance components of fuel cell systems, gears, engines…). The mechanical properties of these components and materials are significantly influenced by their structure at different scales. Enabling the microstructure to become an integral part of the design process of metal components is a key challenge to enhance the usage of new advanced metal alloys for high-performance and light-weighting applications. Computational Homogenization of Polycrystals (CHP) arises as an ideal tool to perform virtual material engineering, providing a relation between material microstructure and its performance. CHP is based on the simulation (either using Finite Elements FE or Fast Fourier Transform based solvers) of the mechanical response of Representative Volume Elements (RVE) of the polycrystalline microstructure under imposed loading paths and environmental conditions. Digimat-MF and Digimat-FE propose a complete framework to conduct such simulations. This framework includes polycrystal and texture generation, crystal plasticity, mean-field approach and FE/FFT solvers. The presentation will illustrate the efficiency of that workflow to predict texture evolution in forming processes, strength, and evolution of plastic anisotropy. Such simulation workflow can also be applied to perform a localization study. Starting from a cold forming simulation within Simufact, the loading path seen by a particular material point in the forming FE model is applied to the polycrystalline RVE to determine the local evolution of the texture and the yield locus. Finally, another aspect of Digimat-MF devoted to forming-limit diagrams (FLD) will be presented. Sheet formability is commonly evaluated based on such FLD in the sheet-metal forming industry. However, the experimental measurement of FLD is a difficult, time consuming and expensive process. Exporting formability of metallic sheets from our virtual testing tools replaces many of the experimental measurements. In this presentation, we will analyze forming-limit strains of metals using J2 plasticity or crystal plasticity mean-field models in conjunction with an imperfection-based approach.