Plastic flow of porous materials in friction contact area

Abstract

The instantaneous stress-strain rate in an infinite hollow cylinder of porous plastic material subjected to simultaneous radial compression and twisting by shear stresses applied to the cylinder surface is considered. It is assumed that the cylinder material obeys the cylindrical yield criterion and associated flow rule. The asymptotic behaviour of the equivalent strain rate in the vicinity of the maximum friction surface is studied. It is shown that the distribution of this quantity follows the inverse square root rule near the maximum friction surface. It is noted that the same dependence is observed in the case of incompressible perfect rigid-plastic material. The strain rate intensity factor is found and is compared to the value derived from the corresponding perfect rigid-plastic solution.