By means of micromechanics and statistical method

the non linear consitutive relation of particulate reinforced polymer is studied.In the deformation process

the debonding damage of the particle matrix interface may occur and will lead to microvoid nucleation.The statistical behavior of microvoids' nucleation and evolution are investigated by using Eshelby's equivalent inclusion method and Mori Tanaka's mean stress field concept.The stiffness of the material will decrease due to microvoid evolution and the macroscopic constitutive relation will gradually be changed from linear one to nonlinear one.Such a phenomenon

on the other hand

shows that the material may be toughened.The reinforcing effect due to intact rigid particles and the weakening effect due to microvoids evolution

as well as their coupling effect on the macroscopic constitutive relations are studied in this paper.The influences of interface strength particle-size dispersity

and average particle-size on the macroscopic constitutive relation are also discussed.The research results indicate that higher interface strength

lower particle size dispersity

and smaller average particle size will be effective for reinforcing and toughening polymer materials under the condition that matrix strngth is higher than interface strngth.