Micromechanics of void growth at high rates

The aim of this work, based on a micromechanical approach, is to caracterise the behavior of porous material under dynamic conditions. The porous media is represented by an aggregate of hollow spheres. With use of a virtual velocity field, an analytical link between the porosity, the macroscopic strain rate and the macroscopic stress is obtained and provides the viscoplastic behavior of the porous media. The results of Carroll and Holt (1972) [l] concerning the dynamic compression of a porous aluminium are retrieved. The present model is not limited to spherical loadings. An application to an axisymmetric tensile path enlights the role of triaxiality on the evolution of voids