Energy Absorption of Folded Shrink Tubes with Gradient Stiffness

Thin-walled tube is a common energy-absorbing structure. The introduction of folds in thin-walled tube can induce the deformation of thin-walled tube, reduce the initial peak force of buckling of thin-walled tube and improve the energy absorption of thin-walled tube effectively. At present, when the folded tubes subjects to axial compression, the crushing force decreases significantly after the initial peak force, which lowers the energy absorption performance of folded tubes. In order to further reduce the initial peak force and increase the total energy absorbed of the folded tube, different forms of folded tube are introduced into the square tube to obtain a folded shrink tube. The relation between force and displacement and deformation of the designed folded tube under the quasi-static compression is obtained by using ABAQUS/Explicit. The results show that the collapse force of the folded shrink tube is in the form of a gradient during the compression process. Compared with traditional square tube and diamond tube, the folded shrink tube not only has lower initial peak force, but also can greatly improve the total energy absorption. The influence of geometric parameters on the performance of the folded tube was studied systematically. The best performance folded shrink tubes were obtained.