Effective anisotropic stiffness of inclusions with debonded interface for Eshelby-based models

Abstract

Inclusions in short fiber reinforced composites (SFRC) suffer from debonding and cannot be directly modeled using Eshelby based mean field methods. This paper proposes a method of treatment of inclusions with debonded interface by replacing them with a fictitious “equivalent bonded inclusion” (EqBI) whose properties are calculated based on the reduced load bearing capacity of the inclusion due to the debonded interface. Approximate expressions are derived for stress redistribution in an inclusion due to the presence of debonded interface for the six elementary loading cases and the corresponding terms in the stiffness tensor are estimated as a function of the reduced average stress in the inclusion. Mechanical equivalence of the EqBI is confirmed by comparison with finite element models having inclusions with debonded interface and the overall stress strain response of a SFRC composite is validated against experimental data.