Stability of Frictional Materials

Abstract

The stability of frictional materials that display a nonassociated flow rule is discussed. Particular emphasis is put on an analysis of recent experiments conducted by Lade et al. (1987), where stable behavior was observed, when the material was expected to be ``unstable'' in the sense of Drucker's stability postulate. It was therefore concluded that Drucker's postulate regarding material stability is not valid for frictional materials. In the present paper, the writers present an analysis and describe features in the experiments by Lade et al. that show that the reported stability may be less surprising.