Acta mater. 47, 143-148, 1999
R. Gradinger¹ and F.G. Rammerstorfer²
²Institute of Lightweight Structures and Aerospace Engineering,
TU Wien, Vienna, Austria
The efficiency of energy absorbing materials in crash elements is, besides
others, strongly influenced by their stress-strain behavior under uniaxial
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
microgeometrical parameters should not vary too much in order to achieve
optimum specific energy absorption.
Strong meso-inhomogeneities lead to strain localization and, consequently,
to a decrease of the initial plateau stress and to increasing ascents
in the plateau regime, both reducing the energy absorption efficiency.