Mechanics of lightweight aluminium foam wrapped in carbon fibre reinforced composites

Lightweight materials that offer great benefit in stiffness and strength to weight ratio plus improved specific energy absorption capability for crashworthiness are constantly being studied. This is even more importantly so as the global climate becomes unpredictable due to large quantities of exhaust pollution in the atmosphere. The objective of this paper is to investigate and gain an understanding of the reinforcing effect of aluminium foam wrapped in carbon fibre composite. This lightweight hybrid load bearing structure is studied under three major collapsing modes, axial compression, bending and torsion. All tests were overall carried out under quasi-static at a rate of 0.3 mms(-1) and impact at a rate of 5 ms(-1). The results show that by increasing the weight by merely 6% through wrapping of aluminium foam with carbon composite, the specific energies under compression, bending and torsion are substantially increased to 23%, up to 46 times and 108 times respectively. The work also shows that aluminium foam is not a load bearing structural material if used on its own as it is brittle and lacks long term geometrical stability. Hence it can only, for the time being, be used as a filler in space frames for vehicles, thus offering considerable reinforcing effect with high energy absorption capability that also warrantees crashworthiness.