Multiaxial crushing of open-cell foams

Abstract

The paper investigates the crushing behavior of low-density foams under triaxial loadings. A micromechanically accurate cubical model of an Al-alloy random open-cell foam is surrounded by three pairs of orthogonal rigid planes and crushed simultaneously in three directions. The foams are crushed along radial displacement paths to volume changes of 70%. For all loading paths the foam traces initial stiff and stable branches during which it deforms as an elastic, isotropic solid. The branches terminate into stress maxima followed by localized crushing in narrow bands of cells. The crushing spreads with limited additional effort with crushed and relatively undeformed cells coexisting. The deformation becomes uniform again once the crushing has spread to the whole domain. Reported are stress-displacement responses in the three directions, and corresponding foam deformed configurations; the mean stress-volume change responses; and the energy absorbed as a function of the volume change. The results point to the need for constitutive models that can capture this partially unstable crushing behavior.