Abstract

An accident or crash is an occurrence, where a force is imposed on the occupant during a very short period of time. Therefore, in designing the car structure and body, the accident time is increased to the most possible value. The purpose of the structure and body design is to absorb the maximal energy in the accident. This research tried to design and optimize a crash box to absorb the maximum energy and minimum force in the longitudinal and transverse impacts of the crash. A numerical simulation and an experimental test have been done to ensure its response accuracy. After taking a proper finite element model, considering the factors and variables levels in the structure, optimization has been also done to determine the best plan for maximum energy and minimum force absorption objectives. In this research, three factors of sheet thickness, number of inner squares, and profile material were considered with three levels for each factor. The thickness of 2, 4 and 6mm, the number of squares 1, 4 and 9 and the materials of aluminum, steel and copper have been investigated. They showed that the optimal thickness and the number of squares are 6mm and 9 respectively.

Keywords: Structural energy absorber; Vehicle crash behavior; Bending test; Longitudinal and transverse impact