Non linear homogenization approach of strength of nanoporous materials with interface effects

The development of nanocomposites and nanoporous materials in the last two decades has stimulated tremendous researches aiming particularly to predict particles or voids size effects on the mechanical behavior. However, few studies have been devoted to nonlinear behavior of this class of materials. The present paper investigates the strength property of ductile (plastic) nanoporous materials by means of a non linear homogenization approach. The material under stake is composed of a rigid-ideal plastic solid matrix (assumed to obey to von Mises criterion) and of spherical nanosized voids. The theoretical procedure consists in an extension of the so-called modified secant moduli method in which an interfacial strength is appropriately accounted. It delivers a general equation giving the macroscopic strength, from which is derived a closed-form expression which explicitly accounts for voids size effects. Finally, we take advantage of these new results to discuss the validity of some recent models available in literature.