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 o f 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 siz es, 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 t he plateau regime, both reducing the energy absorption efficiency. (C) 1998 Acta Metallurgica Inc. Published by Elsevier Science Lid. AII rights reser ved.