A simple approach to estimate failure surface of polymer and aluminum foams under multiaxial loads

From mechanical point of view, it is required to have a criterion for evaluating the failure of cellular solids (foams) under multiaxial loads. Well-documented experimental results in the literature show foams could fail by several mechanisms, e.g., elastic buckling, plastic yielding, brittle crushing or brittle fracture. In the previous years, both theoretical and phenomenological approaches have been applied to obtain the failure surface of various foams. The purpose of this paper is to present a simple approach to estimate the complete failure surface of “non-textured” foams. The predicted results of polymer and aluminum foams are compared with the experimental results reported in the literature. It is found that three selected tests will be sufficient to estimate the complete failure surface of a foam. The recommended testing stress states are σ₁=σ₂=σ₃>0, σ₁=σ₂=σ₃<0, and σ₁=−σ₂=−σ₃ (or σ₁=−σ₂, σ₃=0).