Incremental damage theory of particle or short-fiber reinforced composites

In particle or short-fiber reinforced ductile-matrix composites, cracking of reinforcements is a significant damage mode because cracked reinforcements lose load carrying capacity. This paper deals with an incremental damage theory of the composites. The composite in damage process contains intact and cracked reinforcements in a matrix. To describe the load carrying capacity of the cracked reinforcement, the average stress of a broken ellipsoidal inhomogeneity in an infinite body is introduced. An incremental constitutive relation of particle or short-fiber reinforced composites including the progressive cracking damage of reinforcements and the plasticity of matrix have been developed based on the Eshelby's equivalent inclusion method and Mori and Tanaka's mean field concept. Influence of the reinforcement damage on the stress-strain response of the composites is demonstrated.