Quasi-static axial compression of thin-walled tubes with different cross-sectional shapes

Recently more attention has been paid to the energy absorption capability of novel structures in the retrofit of impact or blast protection structure. As the most versatile components, thin-walled metal tubes with different cross-sections are used and specifically explored by many researchers. One method for improving crashworthiness performance under quasi-static axial crushing is to vary the cross-sectional shape with only convex polygons. As an alternative, it is also necessary to develop tubes with concave polygon sections. In this paper, four types of geometries are studied experimentally. They are hexagon, octagon, 12-sided and 16-sided star, respectively. Experimental data are then compared with those predicted from FE simulations using ABAQUS. It is shown that the experimental and the corresponding numerical results are in agreement with each other. The increase in the number of inward corners demonstrates a promising improvement in energy absorption, but to a certain extent. It is found that the 12-sided star shape has the best energy absorption capability when D/t ratio is less than 50, where D is notional diameter and t is the thickness. The 16-sided star shape performed poorly compared to the others studied.