ABOUT MECHANISM OF CAVITY FORMATION INSIDE A BALL UNDER ITS EXTERNAL SHOCK LOADING

V.Yu. Meltsas, V.N. Rodigin
VANT. Ser.: Mat. Mod. Fiz. Proc 2000. Вып.2. С. 58-62.

A model using acoustic approximation to describe a shock wave converging to the centre and the one reflected from it in a ball is proposed. The model takes into account the possibility of unrestricted cumulation converging to the wave centre.
    Within the model the interference of the incident wave and of the wave reflected from the center is demonstrated to result in their "self--extinction". In response to it, immediately after the incident wave front focusing a restricted and constant uniform material tension is established close to the centre for the period of the wave action. In this situation, when material strength is sufficient enough, no cavity is formed in a ball. Otherwise the cavity can be formed, which is in qualitative agreement with known experiments.
    A numerical example is offered, showing that in the case of incident wave front smearing, when the wave is brought into focus, cumulation can not be infinite.