On the influence of meso-inhomogeneities on the crush worthiness of metal foams

The efficiency of energy absorbing materials in crash elements is, besides others, strongly influenced by their stress-strain behaviour under uniaxial compression. Theoretical, i.e. meso-mechanical, and experimental studies of the influence of meso-inhomogeneities of the cell structure on the crash worthiness of aluminium foams are dealt with. It is shown that the cell sizes, the cell wall thicknesses and other micro-geometrical parameters should not vary too much in order to achieve optimum specific energy absorption. Strong meso-inhomogeneities lead to strain localizations and, consequently, to a decrease of the initial plateau stress and to increasing ascents in the plateau regime, both reducing the energy absorption efficiency. (C) 1998 Acta Metallurgica Inc. Published by Elsevier Science Lid. AII rights reserved.