Numerical investigations on a new type of energy-absorbing structure based on free inversion of tubes

A new type of structure, called retractable tube, is introduced in the present work to overcome the drawbacks of two traditional types of invertubes. The inversion processes of the proposed tubes under axial compression are simulated by using the non-linear finite element code LS-DYNA and the features of the force–displacement curves and the deformation modes of the proposed tubes are analyzed. A comparative study is conducted to compare the energy absorption characteristics of the new proposed tubes with the plain circular tubes based on the performance indices used most commonly for energy-absorbing devices. The results show that the whole efficiencies of the new proposed tubes are significantly higher than those of the corresponding plain circular tubes. In addition, a parametric study is carried out to investigate the effects of geometric parameters on the behavior of retractable tubes.