Simulation of Deformation and Fracture in Polycrystalline Aluminum Alloy under Dynamic Loading

A numerical study is conducted on the influence of the polycrystalline structure, strain rate, and constrained boundary conditions on the plastic strain localization and fracture of 6061-T6 aluminum alloy under dynamic loading. The investigation is carried out on a three-dimensional polycrystalline structure generated by the step-by-step packing method. The deformation behavior of 6061-T6 aluminum alloy under different strain rates and temperatures is described using a relaxation constitutive equation. The initiation and growth of cracks are taken into account using a strain criterion. The developed models and polycrystalline structure are implemented into the ABAQUS/Explicit finite element package to simulate tension of the aluminum samples. It is shown that taking into account the polycrystalline structure leads to lower values of the macroscopic yield stress in comparison with a homogeneous sample. The strain rate and constrained boundary conditions are shown to affect the crack initiation site and fracture patterns.