Incremental sequential homogenization on effective elastoplastic properties of composites with functionally graded interphase

Based on a novel incremental sequential homogenization scheme, this paper investigates elastoplastic behavior of composite with functionally graded interphase. The scheme aims to obtain effective consistent tangent moduli of composites under infinitesimal strain load. The effective moduli in each load step is investigated via two procedures. Firstly, a multi-coated model is established to represent the functionally graded interphase. Phases of the model are virtually added from outside to inside. Then homogenization is applied with help of the temporary effective properties obtained in virtually adding. During homogenization, phases obey classical J2 plasticity and their plastic operators are implemented to acquire effective elastoplastic responses of composite. Validation of present method is conducted by available models and experimental results. In the end, influences of thickness/yield stress of interphase and aspect ratio/volume fraction of reinforcement on elastoplastic behavior of composite are studied. Based on present model, interphase and reinforcement enhance load capacity of composite by changing elastic and plastic strain distributions within each phase.