On small deformation interfacial debonding in composite materials containing multi-coated particles

This paper presents an integrated theoretical and computational investigation into the macroscopic behavior of composite materials containing multi-phase reinforcing particles with simultaneous nonlinear debonding along the microconstituent interfaces. The interfacial debonding is characterized by the nonlinear Park-Paulino-Roesler potential-based cohesive zone model. The extended Mori-Tanaka method is employed as the basis for the theoretical model, which enables micromechanical formulations for composite materials with high particle volume fractions. The computational analysis is performed using a three-dimensional finite element-based cohesive zone model with intrinsic cohesive elements. To place the generality and robustness of the proposed technique in perspective, we consider several examples of composite materials with single or double separation along the interfaces of coated particles. The effects of many microstructural parameters, such as the geometry of the microstructure, the location of debonding, the material properties of the coating layer (i.e. homogenous and functionally graded coatings), and the fracture parameters, are comprehensively investigated by both theoretical and numerical approaches. We verify that both theoretical and numerical results agree well with one another in estimating the macroscopic constitutive relationship of corresponding composite materials. The strong dependence of the overall response of composite materials on their microstructure is well recognized for all hardening, snap-back, and softening stages.