Modelling ductile fracture at high strain rates in shear sensitive materials

Several ductile alloys show an equivalent fracture strain in pure shear significantly lower than the that for uniaxial tensile stress. This behavior as be ascribed, beside the reduced number of slip systems, to the concurring contribution to ductile fracture process of intervoid sheeting mechanism. Under high strain rate loading, this mechanism can be promoted further by temperature effect resulting from quasi-adiabatic condition. Recently, Bonora and Testa (2022) developed a plasticity damage self-consistent (PDSC) model, which incorporates stress triaxiality and Lode angle controlled fracture mechanisms, reconciling CDM theoretical framework with ductile fracture mechanisms and their sequential progression under general loading conditions. In this work, PDSC model has been used to model ductile fracture in Al2024-T351 under different stress state conditions at high strain rates including dynamic compression in hat-shaped specimen, Taylor cylinder impact and plate impact experiments. The ability of the proposed model to accurately predict the overall specimen response as well as ductile fracture initiation and propagation, and fracture mode is shown.