COMPOSITE POWER LAWS IN SHOCK FRAGMENTATION

Inspired by the discovery of Oddershede et al. [Phys. Rev. Lett. 71, 3 107 (1993)] concerning the dimensionality dependence of mass distribut ions after shock fragmentation, we have performed further experiments using thick plates of dry clay. We observe mass distributions with com posite power laws, i.e., different exponents for fragments larger and smaller than the plate thickness. This implies that the dominant expon ent for any given fragment mass corresponds to the dimensionality of t he original object on the length scale of the fragment considered. We study two profoundly different models, both of which agree qualitative ly with the observed features. Thus the measured mass distribution tel ls little about the mechanisms of the fragmentation process.