Material-point simulation of cavity collapse under shock

The collapse of cavities under shock is a key problem in various fields ranging from erosion of material, ignition of explosive, to sonoluminescence, etc. We study such processes using the material-point method developed recently in the field of solid physics. The main points of the research include the relations between the symmetry of collapsing and the strength of shock, and other coexisting interfaces, as well as hydrodynamic and thermal-dynamic behaviours ignored by the pure fluid models. In the case with strong shock, we study the procedure of jet creation in the cavity; in the case with weak shock, we found that the cavity cannot be collapsed completely by the shock and that the cavity may collapse in a nearly isotropic way. The history of collapsing significantly influences the distribution of 'hot spots' in the shocked material. The change in symmetry of collapsing is investigated. Since we use the Mie-Grueneisen equation of state and the effects of strain rate are not taken into account, the behaviour is the same if one magnifies the spatial and temporal scales in the same way