Optimisation for minimum weight of foam-filled tubes under large twisting rotation

The plastic resistance of foam-filled tubes undergoing large twisting rotation was studied analytically and numerically. The mechanical properties and constitutive behaviour of the aluminium foam were discussed first. A simple uncoupled yielding model of aluminium foam was employed in the numerical simulations to analyse the strengthening effect of foam filling on the plastic resistance of thin-walled tubes undergoing torsion. The derived solutions to the torsional resistance and critical twisting rotation were then integrated with the numerical optimisation technique to minimize the weight of the foam-filled sections with crashworthiness constraints. The optimisation results showed that there is up to 70% increase in specific energy absorption of the filled sections compared to non-filled ones.