Crashworthiness optimization of empty and filled aluminum crash boxes

Dynamic crash tests on empty, honeycomb-filled and foam-filled square aluminum tubes have been performed. Furthermore, in order to find more details about crash processes, finite element simulations of the experiments have been done. In terms of finding more efficient and lighter crash absorbers and achieving maximum energy absorption, Multi design optimization (MDO) technique has been applied for optimizing the square and circular tubes. Based on practical requirements the optimum tube geometry which absorbs maximum energy and has a minimum weight has been determined. The results of simulations of filled identical tubes with honeycomb and foam with the same density showed that the foam behaves better than honeycomb. Results of previous work indicated that using high density honeycomb for filling the tubes will result in more energy absorption but the weight efficiency has been lost (H R Zarei, M Kroger M and K Popp, 'Experimental and numerical quasi static crash investigation in empty and honeycomb filled aluminum square tubes', Int F Crashmorthiness, May 2005, submitted). Therefore, a comprehensive study has been performed in order to find out the crash behavior of tubes filled with foam with different densities. The MDO procedure has been implemented to find an optimum filled tube that absorbed the same energy as an optimum empty tube can absorb.