A computational homogenization of random porous media: Effect of void shape and void content on the overall yield surface

• Overall yield surface of porous media in relation to the RVE representativity.
• Influence of void shape and void content on the overall yield surface.
• Extension of the Gurson-Tvergaard model based on the computational data.

A computational homogenization study of three-dimensional cubic cells is presented to estimate the overall yield surface of random porous media covering a wide range of stress triaxiality ratios. The representativity of the overall yield surface estimates is examined using cubic cells containing randomly distributed and oriented voids with different volume fractions and shapes (spherical and oblate/prolate). The computational results are compared with some existing Gurson-type yield criteria. The extension of the Gurson-Tvergaard model recently proposed by Fritzen et al. (2012) for spherical cavities is shown in good agreement with the computational results for all investigated porosities.