Effect of the cross-sectional shape of hat-type cross-sections on crash resistance of an "S"-frame

This paper addresses a design aspect of a front side rail structure of an automobile body from the point of view of weight efficiency and crush energy absorption. Various orientations of the cross-section and ways of reinforcing the cross-section by an internal stiffening member are investigated. The specific energy absorption (i.e. energy absorption per unit weight) is taken as a measure of the performance of a structure. Also the advantages of reinforcing the side rail by means of aluminum foam filling are assessed. It is shown through extensive numerical simulation using nonlinear finite element code PAM-CRASH, that the model with a diagonally positioned internal stiffener and suitable triggering dents can absorb up to 200% more energy than the typical double-hat/double-cell profile member. At the same time there is a 3 fold increase in the specific energy absorption. By using the concept of aluminum foam-filling with 3 MPa Foam, the specific energy absorption increases by a factor of 2.84, (C) 2001 Elsevier Science Ltd. Ail rights reserved.