Micromechanics of void growth at high rates

The aim of this work, based on a micromechanical approach, is to caracteris e the behavior of porous material under dynamic conditions. The porous medi a is represented by an aggregate of hollow spheres. With use of a virtual v elocity field, an analytical link between the porosity, the macroscopic str ain rate and the macroscopic stress is obtained and provides the viscoplast ic behavior of the porous media. The results of Carroll and Holt (1972) [1] concerning the dynamic compression of a porous aluminium are retrieved. Th e 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.