Mesoscopic simulation of inhomogeneous metallic foams with respect to energy absorption

The subject of this work is metallic foams under crush and crash loading th e focus being on the influence of inhomogeneities of the apparent density o n the maximum stresses and the energy absorption behavior during compressiv e deformation. Based on an analytical description of the uniaxial stress-st rain relationship of cellular materials, which is fitted to experimental re sults, a relation between the effective density and the static compression behavior of a certain brand of metallic foams can be obtained. This relatio n is implemented into a mathematical model, which represents the material a s an array of point masses connected by longitudinal, nonlinear springs and transversal, rigid cross-bridges, which can be opened or closed as require d. Several distributions of mesoscale inhomogeneities are studied and asses sed with respect to their influence on the energy absorption and impact dam age protection potential. It is shown that only a mesoscopically homogeneou s foam fully exploits the energy absorption potential of a foam of a given apparent density. The effects of inertia are shown by simulating impact eve nts. The stress waves propagated and reflected in the homogenized foam mate rial and their influence on the impact response are described. (C) 1999 Pub lished by Elsevier Science B.V. All rights reserved.