Failure Development in Particulate Composites

We present a model capable of evaluation of principal micromechanical processes taking place in brittle matrix composites reinforced by ductile particles. The reinforcing mechanism is based on formation of a system of restrictive forces imposed on the crack surfaces by the plastic particles behind the propagating crack front. The particles form the bridging zone and, thus, constrain the crack opening. This is the principal aspect of the toughening mechanism in these systems. The developed model addresses the effects associated with the discrete particle distribution and particle-matrix interface properties. The developed analytical approach allows us to trace the crack propagation through this system at any intermediate step. This detailed analysis explains certain aspects of the particulate reinforcement mechanism not discussed in the literature previously. The crack growth resistance curves are presented for several composite systems.