INCREMENTAL THEORY OF PARTICULATE-REINFORCED COMPOSITES INCLUDING DEBONDING DAMAGE

An incremental theory is developed to describe the elastic-plastic beh avior and damage behavior of particulate-reinforced composites, based on Eshelby's (1957) solution for an ellipsoidal inclusion and Mori and Tanaka's (1973) concept of average stress/strain for a finite concent ration of particles. In the composites containing hard spherical parti cles in a ductile matrix, debonding of the particle-matrix interface i s a significant damage process, since the accumulation of the debondin g damage affects the deformation and strength of the composites. The d ebonding damage is assumed to be controlled by the stress of the parti cle and the statistical behavior of the particle-matrix interfacial st rength. During debonding, the stress of the particle is released and t he site of the particle is regarded as a void, resulting in a void con centration which increases with deformation. The theory describes not only the reinforcing effect due to the intact particles but also the w eakening effect due to the damaged particles. Analysis of the stress-s train response under uniaxial tension has been carried out on the part iculate-reinforced composite based on the present theory. The influenc e of the damage on the stress-strain relation of the composite is very strong and depends on the statistical properties of the particle-matr ix interfacial strength.