Coupled ASB-and-microvoiding-assisted Dynamic Ductile Failure

Adiabatic shear banding (ASB) is a dynamic localization phenomenon resulting from thermomechanical instability under high strain rate and low stress triaxiality loading conditions. High strength, steels and lightweight alloys of titanium and aluminum are highly susceptible to this phenomenon which leads to premature material failure. At an advanced stage of the localization process, the adiabatic shear bands have been shown to contain micro-voids which coalesce to form cracks and ultimately lead to the fracture of the structure. A physics-motivated, unified constitutive model accounting for the coupled effects of ASB and micro-voiding has been developed in the context of large deformation, high strain rate and high temperature rise. The enlarged model is herein implemented as user material into the engineering finite element (FE) computation code LS-DYNA in the context of standard FE kinematic formulation and its performances are assessed.