Effect of Crystal Plasticity Parameters on Microscopic Stress Distribution in Polycrystalline Aggregate Model

Crystal plasticity parameters for numerical simulations are difficult to experimentally measure on the microscopic scale. One possible approach to avoid the difficulty is to determine the parameters that can be used to reproduce the stress-strain curve by employing a polycrystalline aggregate model. In this study, the effect of crystal plasticity parameters on stress-strain curves on a macroscopic scale and on stress distribution on a microscopic scale was investigated by using polycrystalline aggregate simulation. The parameters investigated were initial slip strength (t(0)), initial hardening modulus (h(0)) and saturation slip strength (tau(s)). The effect of these parameters on macroscopic stressstrain curves was found to be the followings: t(0) controls the yield stress or proof stress, and both h(0) and ts control the strain-hardening behavior. The effect of these parameters on microscopic stress distribution was also investigated because similar stress-strain curve can be obtained by using different sets of crystal plasticity parameters. Consequently, even if these parameters are slightly different, a similar microscopic stress distribution can be obtained by properly reproducing the macroscopic stress-strain curve.