Comput.Mater.Sci. 16, 61-69, 1999
T.Daxner, H.J. Böhm and F.G. Rammerstorfer
Institute of Lightweight Structures and Aerospace
Christian Doppler Laboratory for Micromechanics of Materials,
TU Wien, Vienna, Austria
The subject of this work is metallic foams under crush and crash loading, the
focus being on the influence of inhomogeneities of the apparent density on the
maximum stresses and the energy absorption behavior during compressive
Based on an analytical description of the uniaxial stress-strain relationship
of cellular materials, which is fitted to experimental results, a relation
between the effective density and the static compression behavior of a
certain brand of metallic foams can be obtained.
This relation is implemented into a mathematical model, which represents the
material as an array of point masses connected by longitudinal, nonlinear
springs and transversal, rigid cross-bridges, which can be opened or closed as
Several distributions of mesoscale inhomogeneities are studied and assessed
with respect to their influence on the energy absorption and impact damage
It is shown that only a mesoscopically homogeneous foam fully exploits the
energy absorption potential of a foam of a given apparent density.
The effects of inertia are shown by simulating impact events.
The stress waves propagated and reflected in the homogenized foam material
and their influence on the impact response are described.