Experimental and Numerical Analysis on buckling and control amount of Energy Absorption of square bitubular shock absorbers under quasi-static and dynamic axial Loading

Today, energy absorbers are used to reduce the damage caused by collision. Thin-walled structures are the most popular energy absorbent and is used in various forms. Thin-walled tubes due to lightness, high value of impact energy absorption, long crushing length and high ratio of energy absorption into weight have ever-increasing application as one of the effective energy absorption. The purpose of this study was to investigate the effect of geometry deformation on the energy absorption of brass tubes with square cross-section and the effect of combined bitubular tubes to absorb more energy under Axial Loading. In the experimental part, brass tubes with square cross-section were prepared and then the quasi-static tests with static loading rate were performed and the load-deflection diagrams in each test were obtained. A numerical model is presented based on finite element analysis to simulate the collapse process considering the non-linear responses due to material behavior, contact and large deformation. The comparison of numerical and experimental results showed that the present model provides an appropriate procedure to determine the collapse mechanism, crushing load and the amount of energy absorption. The validated finite element model was then used for the parametric studies, in order to determine the effect of the geometry parameters (i.e. imperfection and thickness) and dynamic loading parameters (i.e. impact mass and impact velocity) on the energy absorption.