Investigation of mechanical behavior of multi-cellular tubes with intermediate walls under lateral quasi-static loading

Energy absorbers are one of the most important structures in the automotive, shipping and aerospace industries. These structures are made in two types: reversible and irreversible. In this study, thin-walled irreversible energy absorbers were investigated. These absorbers are a new type of multi-cellular structure consisting of several concentric cylinders and two perpendicular walls, and their mechanical behavior and collapse properties have been studied under quasi-static lateral loading. The present study has been done by experiments and simulations. For simulations, LS-DYNA was used and three different groups of absorbers were simulated, including mono-cylindrical, bi-cylindrical (C2) and tri-cylindrical. According to the results obtained from the force-displacement curves, it was found that increasing the thickness in each of the components, including the walls and cylindrical shells, leads to increasing the mechanical properties such as specific energy absorption, maximum force and crushing force efficiency. Also, a comprehensive analysis was performed on the force-displacement curves of these structures. It was observed that for each group of absorbers, the collapse of each wall causes peak force s in the force curve. It was also observed that in Group C2 absorbers, the collapse of the cylinders had a more uniform force curve compared to the collapse of the walls, and the greater the thickness of the cylinders and the smaller the thickness of the walls, the smaller the difference between the uniform part and the peak force.