Elastic and elastoplastic multi-Level damage models for composites with imperfect interface

Abstract

Micromechanics-based multi-level damage models are presented to predict elastic and elastoplastic overall behavior and damage evolution in composite materials. First of all, Eshelby’s tensor for an ellipsoidal inclusion with slightly weakened interface is adopted to model particles with imperfect interface in particle reinforced composites and fibers with imperfect interface in fiber reinforced composites, respectively. Imperfect interfaces between inclusion and matrix in composites occur as deformations or loadings continue to increase. As an effort to realistically reflect the effect of loading history on the progression of imperfect interface, a multi-level damage model in accordance with the Weibull’s probabilistic function is developed. It is assumed that the progression of imperfect interface is governed by the average stress of inclusion. To the estimate overall elastoplastic behavior of ductile matrix composites, an effective yield criterion is derived based on the ensemble-volume averaging process and the first-order effects of eigenstrains due to the existence of spherical inclusions. As applications, the overall elastic and elastoplastic stress-strain curves of particle reinforced brittle matrix composites, particle reinforced ductile matrix composites, and unidirectional fiber reinforced brittle matrix composites under uniaxial, biaxial, and triaxial loading are investigated in detail. A series of parametric analysis are carried out to investigate the influence of model parameters. Furthermore, the proposed multi-level damage models are compared with available experimental data in the literature to verify the accuracy of the models. Finally, proposed micromechanics-based evolutionary multi-level damage model for unidirectional fiber reinforced composites is implemented into a finite element program ABAQUS to predict behavior of laminated composites under various loading conditions.