Investigating the microstructural effect on elastic and fracture behavior of polycrystals using a nonlocal lattice particle model

A novel nonlocal lattice particle framework is proposed to investigate the microstructural effects, such as the crystallographic orientation distribution and grain boundary properties, on the mechanical performance of 2D polycrystalline materials. The classical approach of treating material anisotropy in other numerical methods, such as finite element method, is by transforming the material stiffness matrix for each crystallite. In the proposed method, the polycrystalline microstructures are constructed by rotating the underlying topological lattice structure consistently with the material crystallographic orientation while keeping the material stiffness matrix intact. By rotating the underlying lattice structure, the grain boundaries between different grains are naturally generated at locations where two crystallites meet. Thus, the grain boundary effect on the performance of the crystalline aggregates can be naturally incorporated. Parametric studies on the effects of crystallographic orientation distribution on both elastic and fracture behavior of polycrystalline materials are performed. The simulation results are compared with both analytical solutions and experimental observations in the open literature. Conclusions and discussions are drawn based on the current study.