Crushing analysis and multi-objective optimization of bitubular hexagonal columns with ribs

Abstract

In order to improve the crashworthiness of thin-walled columns, the energy absorption characteristics of three columns under quasi-static axial crushing loads were analyzed through LS-DYNA. Numerical results show that the energy absorption capability of the bitubular hexagonal columns with middle to middle (MTM) ribs is the best, followed by the bitubular hexagonal columns with corner to corner (CTC) ribs and the bitubular hexagonal columns without (NOT) ribs, respectively. Then, the MTM rib was optimized by using multi-objective particle swarm optimization algorithm. Through the analysis of the Pareto front for specific energy absorption (SEA, A se) and peak crushing force (PCF, F pc), it is found that there is a vertex on the Pareto front. The vertex has the design parameters of t 1=1.2 mm, t2=1.2 mm, A se=11.3729 kJ/kg, F pc=235.8491 kN. When the PCF is in a certain size, on the left of the vertex, the point with t 2=1.2 mm has the biggest SEA, meanwhile on the right of the vertex, the point with t 1=1.2 mm has the biggest SEA. Finally, the global sensitivity analysis was conducted to investigate the effect of two design parameters. The result is obtained that both SEA and PCF for MTM are more sensitive to t 1 rather than t 2 in the design domain.