Micro-macro modeling of debonding in inclusion reinforced composite materials

Mechanical behavior of inclusion-reinforced composites is affected by the nature of the bond between the constituents. Imperfect bonding may result either from the manufacturing process or from damage development when the composite is loaded. For linear elastic materials, it lowers the effective elastic modulus. For non-linear (e.g. plastic) material models, debonding between harder and softer phases may be at the origin of micro cracking, shear banding, or ductile damage. The first part of the thesis proposes particular solutions allowing the determination of the effective properties of the composite for particular cases of loading, such as the deviatoric tension loading. The solution is based on the theory of linear elasticity coupled with mean field homogenization schemes. The second and main part of the thesis is based on the generalization of the concept of Eshelby’s solution, to account for nonlinear interface debonding between the constituents of a composite material. The solution is incremental and it can work with any kind of cohesive law and under any kind of external loading. Two simplifying hypotheses are adopted. The stress field inside the spherical particle as well as the compliance across the interface is considered to be uniform. The Mori-Tanaka method is extended based on the generalization of Eshelby’s solution to account for the effect of nonlinear interface debonding. The extended Mori Tanaka method is able to predict the macroscopic mechanical behavior of a composite material with any kind of cohesive law and external loading.