A PREDICTIVE MODEL FOR THE MECHANICAL-BEHAVIOR OF PARTICULATE COMPOSITES .1. MODEL DERIVATION

A method for predicting the highly nonlinear stress-strain behavior an d dilatation induced by cavitation of highly filled particulate compos ites from constituent properties has been developed. The approach pres ented uses a variation of linear elasticity throughout and has no adju stable parameters, unlike the methods currently used, which require la rge numbers of fitting factors and complicated nonlinear analyses. An energy balance derived from the first law of thermodynamics calculates critical strain values at which filler particles will debond when sub jected to deformation. Repeated calculations of critical strain values using re-evaluated material properties accounting for the damage caus ed by debonding give very nonlinear stress-strain and dilatation curve s. Experimentally observed dependencies on particle size, filler conce ntration, adhesion, and matrix and filler properties are correctly pre dicted. The method can be generalized for any state of stress or parti cle shape. Comparisons of experimental data with the model results giv e good agreement.