Numerical Investigation of Interface Debonding of Particle Reinforced Composites by Unit Cell Model

Due to its high specific stiffness and strength, good damage tolerance capabilities, and good fatigue resistance with respect to the traditional materials, metal matrix composite materials (MMCs) have attracted much research interests in recent years. It is known that interface debonding plays an important role in the thermo-mechanical behavior of the MMCs. In the present study, the effect of interface debonding on the mechanical properties of MMCs has been studied by a new periodic unit cell model, the multi-particle cubic (MPC) model, which is proposed with the consideration of the inhomogeneous structures within the MMCs. The representative cell is constructed by several randomly distributed elastic spheres, matrix material and interfacial region with the perfect bonding initially. And the onset of damage was assumed to follow a maximum normal stress criterion. The simulated results agree well with the experimental results. It is found that with the decrease of interfacial strength, the degradation of the composite resulted from the initiation and propagation of interfacial damage becomes severe. Damage evolution of the interface is further investigated with the increase of plastic strain. In additions, the predictions from the MPC model have also been compared with those from the single particle cubic (SPC) model.