Material-point simulation of cavity collapse under shock

Abstract

The collapse of cavities under shock is a key problem in various fields ranging from erosionof material, ignition of explosive, to sonoluminescence, etc. We study such processes usingthe material-point method developed recently in the field of solid physics. The main pointsof the research include the relations between the symmetry of collapsing and the strengthof shock, and other coexisting interfaces, as well as hydrodynamic and thermal–dynamicbehaviours ignored by the pure fluid models. In the case with strong shock, we study theprocedure of jet creation in the cavity; in the case with weak shock, we foundthat the cavity cannot be collapsed completely by the shock and that the cavitymay collapse in a nearly isotropic way. The history of collapsing significantlyinfluences the distribution of ‘hot spots’ in the shocked material. The change insymmetry of collapsing is investigated. Since we use the Mie–Grüneisen equation ofstate and the effects of strain rate are not taken into account, the behaviouris the same if one magnifies the spatial and temporal scales in the same way.