Development of an improved MMC-based fracture criterion characterizing the anisotropic and strain rate-dependent behavior of 6061-T5 aluminum alloy

Abstract

Fracture behavior of aluminum alloy under complex loading conditions is of particular interest to researchers and practitioners. In this study, tensile tests were carried out on 6061-T5 aluminum alloy specimens at different stress triaxialities and Lode angles under different loading directions at various strain rates. The Hill48 yield criterion and a self-developed hardening model were combined to describe the anisotropic yielding and strain rate-dependent hardening behavior of 6061-T5 aluminum alloy. An improved MMC-based fracture model was developed to describe the anisotropic and strain rate-dependent fracture characteristics of 6061-T5 aluminum alloy and the parameters were calibrated by using a combined experimental-numerical approach. The improved MMC-based model was implemented into LS-DYNA as UMAT for the numerical simulation. By using the proposed fracture criterion, simulation results were highly consistent with experimental ones, which prove the reliability of the improved fracture criterion.