Reza Sistani - Department of Mechanical Engineering, Faculty of Industrial and Mechanical Engineering, Qazvin Branch, Islamic Azad university, Qazvin, Iran
Mahmoud Mousavi Mashhadi - Department of Mechanical Engineering, Faculty of Industrial and Mechanical Engineering, Qazvin Branch, Islamic Azad university, Qazvin, Iran
Younes Mohammadi - Department of Mechanical Engineering, Faculty of Industrial and Mechanical Engineering, Qazvin Branch, Islamic Azad university, Qazvin, Iran

The purpose of this paper is to select the optimal section of different cross-sectional multi-cell hexagonal tubes under axial dynamic loads in three categories of internal edge thicknesses. The explicit non-linear FE code LS-DYNA is employed for numerical simulation. The results of crashworthiness performance criteria are obtained for various alternatives of configurations. TOPSIS method introduces the rank of different sections. The most effective section in the three categories is selected. In the continuation of the research, the straight inner sides of small hexagons were replaced with semi-elliptic and semicircle, but with respect to the symmetry of the larger hexagon diameter and equal perimeter size in order to evaluate the crashworthiness criteria in the selected section.

Dynamic axial load, Crashworthiness criteria, Multi-cell hexagonal tube, Specific energy absorption, TOPSIS method