Numerical study of mechanical behaviour of tubular structures under dynamic compression

This paper presents a novel point of view for the performance investigation and optimization of energy absorber devices, which is numerically introduced using the finite element method employing corrugated tubes. The numerical results show that structural or material softening leads to an optimal configuration at which the corrugated or circular tube achieves its peak performance. The performance and optimization parameters used in this study are absorbed crash energy and specific energy absorption. The force-displacement (f-d) diagram of the energy absorbers is divided into three parts for numerical investigation. The optimum point of each corrugated tube is observed when the values of energy absorption (EA) at different stages of the stroke (i.e., in the first, middle, and last portions of deformation) are almost equal or close to one another. Furthermore, the effect of material softening is discussed. The effects of cladding a ductile layer on f-d diagram, EA and deformation of thin-walled circular tubes are numerically investigated. Adding soft material layers oriented at 30 degrees to 70 degrees to the model can increase the performance of energy absorbers by approximately 10 % compared with the model that uses only the core material.