Micromechanical modelling of porous materials under dynamic loading

The behaviour of porous material under dynamic conditions is assessed by a micromechanical approach. By averaging, a general form for the dynamic macrostress is proposed which recovers the static definition when inertia effects are neglected. In this work. a representative volume element for the porous material is defined as a hollow sphere. Using an approximation of the velocity field and the principle of virtual work. an explicit relationship is found between the macroscopic stress and strain rate. The macrostress tenser is proved to be symmetric. in the present formulation proposed for porous materials. Illustrations are shown for hydrostatic tension or compression and also for axisymmetric loading. In the latter case, the effect of stress triaxiality is captured. (C) 2001 Elsevier Science Ltd. All rights reserved.