Investigating mesh sensitivity and polycrystalline RVEs in crystal plasticity finite element simulations

Crystal plasticity-finite element method (CP-FEM) is now widely used to understand the mechanical response of polycrystalline materials. However, quantitative mesh convergence tests and verification of the necessary size of polycrystalline representative volume elements (RVE) are often overlooked in CP-FEM simulations. Mesh convergence studies in CP-FEM models are more challenging compared to conventional finite element analysis (FEA) as they are not only computationally expensive but also require explicit discretization of individual grains using many finite elements. Resolving each grains within a polycrystalline domain complicates mesh convergence study since mesh convergence is strongly affected by the initial crystal orientations of grains and local loading conditions. In this work, large-scale CP-FEM simulations of single crystals and polycrystals are conducted to study mesh sensitivity in CP-FEM models. Various factors that may affect the mesh convergence in CP-FEM simulations, such as initial textures, hardening models and boundary conditions are investigated. In addition, the total number of grains required to obtain adequate RVE is investigated. This work provides a list of guidelines for mesh convergence and RVE generation in CP-FEM modeling. •Large-scale CP-FEM simulations of single and polycrystals are performed to investigate mesh sensitivity and RVE sizes.•Mesh convergence in CP-FEM simulations is sensitive to the initial crystal orientation and applied boundary conditions.•Approximately 104 finite elements per grain are required to achieve mesh convergence in both single and polycrystals.•Adequate polycrystalline RVE in uniaxial tension is achieved by incorporating an order of 1000 grains.