EFFECT OF THE CROSS-SECTIONAL SHAPE ON CRASH BEHAVIOUR OF A THREE DIMENSIONAL SPACE FRAME

This paper addresses a design aspect of a front rail structure of an automobile body from the point of view of weight efficiency and energy absorption. Various ways of reinforcing the cross-section by an internal flange or diaphragm are investigated. The results are compared with a response of the empty square profile. Also, advantages of a full or partial internal reinforcing by means of aluminium foam of three different densities are assessed. It was shown through extensive numerical simulation that a diagonally positioned internal flange with suitable triggering dents can absorb four times more energy than a referred empty member. At the same time there is 3.4-fold increase in the specific energy absorption. Using the concept of foam filling with 3Mpa foam can still raise the above numbers to six and 3.67, respectively. The above results refer to extruded aluminium profiles.