An ideal energy absorber should be of low weight and maintain the maximum allowable retarding force throughout the greatest possible displacement (stroke length). With respect to these demands the axial compression characteristics of tubular structures that buckle in a progressive manner, can be used to advantage, providing inexpensive and versatile, but nevertheless weight and stroke efficient energy absorbers.
Beside the mass efficiency of Foamed materials their compression characteristics show that they come close to an ideal energy absorber, offering a distinct plateau of almost constant stress in the uniaxial compressive stress-strain curve up to nominal strain values of 70% – 80%. Combination of tubular structure and Foamed material filler seems to be efficient, combining synergetically the advantages of both types of structures.
The CI has done some preliminary researches in this area. Fig. 4 shows the force – displacement behavior of an axially crushed empty tube, Foam and Foam filled tube, showing the interaction effect between the Foam and the tube. The energy absorbed by the tubular component consisting of the metallic tube and the Foam filler is greater than the algebraical sum of those of the Foam alone and tube alone. However, the mechanism of the interaction between the Foam and the outside tube is still not well understood to date.
Fig. 4 Force – displacement behavior of an axially crushed empty tube, Foam and Foam filled tube, showing the interaction effect between the Foam and the tube.
In the present project, tubular component structure consisting of Aluminum/Ceramic composite Foams filled in tubes or frames for Automotive applications will be developed. The manufacturing process for producing the component will be investigated. As shown on Fig. 2, the green precursor of the Aluminum/Ceramic with Foaming agent will be put into a tube or a frame and then be heat treated to Foam. Finally, an integrated structure can be obtained. The mechanism of the interaction between the tube and the Foamed material will be in investigated in this project.