Study of spontaneous adiabatic shear bands in expanding rings under explosion by thermo-elastic-plastic phase field model

Metallic cylindrical shells under explosion load may exhibit complex failure modes, which is a challenge issue in explosive and impact engineering. The thermo-elastic-plastic phase-field model is used in this paper to study the expanding cracks of cylindrical shell under internal explosion load, called expanding rings. The spontaneous adiabatic shear bands (ASBs) evolution is successfully captured by considering the mesh-independent gradient damage characteristics. Thus, the typical experimental phenomena are effectively revealed from the numerical simulations. The evolutionary behavior of the ASBs is analyzed, which is induced by defects and the self-similar structure of ASBs. It is found that the initial defects in the expanding rings dominate the self-organized ASBs. The number of ASBs tends to be saturated with the increase of defects. In addition, a formula for calculating the structural radius of laminar ASBs is proposed, which can well predict the simulation result.