Quasi-static axial crushing of multi-walled (spiral) aluminium tubes fabricated by roll bending: Experimental and numerical investigation

This study investigates the crashworthiness performance of multi-walled (spiral) tubes fabricated by roll bending aluminium alloy sheets. Quasi-static axial crushing tests of specimens were first conducted, and then numerical models were built to simulate the tests using the explicit non-linear finite element code LS-DYNA. After the experimental validation of the numerical simulation, a new series of conventional (closed-section) circular tube models of the same axial length, mean diameter, and cross-sectional area as those of the corresponding spiral models were built for comparison. The deformation patterns of the spiral tubes were found to be virtually the same as those of the closed-section tubes and despite being substantially open-section shells, those with more than two spirals collapsed progressively for crushing lengths that corresponded to 2/3 of their axial length. Moreover, the specific energy absorption, the energy absorption per spiral and the crush force efficiency of the tubes examined improved with respect to the number of spirals reaching peak values for around three to four spirals.