Attempt to improve the material utilisation and crashworthiness of grooved tube subjected to axial crushing

摘要

Grooved tube has proved to be an effective energy absorber due to its excellent controllability during axial crushing. In the present research, a novel energy absorber named two-stage grooved tube is proposed. Three approaches are put forward to improve the material utilisation of grooved tube by reducing the dimensions of thick-walled section. In addition, to enhance the stability and energy absorption performance, aluminium foam is filled in empty grooved tube. An analytical model for foam-filled grooved tube is established, and in which a semi-empirical constant to reflect the tube-foam interaction is determined by fitting test data. The experimental results show that the empty grooved tube with weak thick-walled section always generates non-axisymmetric mode, while the foam filling can significantly improve the structural stability by transiting the non-axisymmetric mode into axisymmetric mode. Foam filling can also obviously enhance the energy absorption performance of empty grooved tube with strong thick-walled section, and all foam-filled cases shows typical two-stage energy absorption characteristics. Moreover, reducing the thickness and length of thick-walled section both can improve the material utilisation of foam-filled grooved tube, while the latter can also significant enhance the energy absorption performance.