Dynamic indentation and penetration of aluminium foams
International Journal of Mechanical Sciences, (2008)DOI: 10.1016/j.ijmecsci.2007.09.006
Abstract
Failure of metal foams caused by dynamic indentation and penetration
is very common in practice,such as light-weight structural sandwich
panels,packing materials and energy absorbing devices. Rational application
of these materials requires a sound understanding of deformation
and energy absorption mechanisms of the aluminium foams as well as
the effect of impact velocity. In this study,following experimental
investigations into compression,tension,sharing and indentation of
CYMAT aluminium foams of various densities,a finite element (FE)
analysis using ABAQUS is conducted for dynamic indentation process
of aluminium foams under a rigid,flat-headed indenter. Two methods
of applying impact velocities are considered: the indenter is pushed
into the foam at a constant velocity through the whole process or
with an initial velocity which then decreases with indentation. Two
energy dissipation mechanisms are considered: compression of the
foam ahead of the indenter and fracture along the indenter edge.
Effect of impact velocity is noted on the size of a localized deformation
and the total energy absorbed. A plastic structural shock theory
developed by previous researchers is applied to calculate the resistance
force with indentation depth during indentation process and fair
agreement is obtained between the analytical and numerical results.