Numerical investigations of the elastic and plastic behaviour of an open-cell aluminium foam

The elastic and plastic behaviour of an open-cell aluminium foam is investigated numerically. Finite element discretisations are used that have been derived from real foam specimens by computer tomography data. By different combinations of boundary velocities in the three directions in space, various multiaxial stress states are realised in the foam. This is done for nine foam discretisations with varying relative density. Thus, the elastic constants, the yield surface and the plastic potential of the foam are determined depending on the relative density. The results of the numerical simulations are: (1) the variation of the Young's modulus in terms of the relative density can be described by a power law relationship. (2) The elastic Poisson's ratio does not depend on the relative density. (3) The yield surface is not rotationally symmetric with regard to the hydrostatic axis. (4) The dimensions of the yield surface vary with a power law relationship in terms of the relative density. (5) The plastic potential is approximately associated to the yield surface for all stress states.