Extruded Aluminum Crash Can Topology for Maximizing Specific Energy Absorption

Specific energy absorption (SEA) is a quantitative measure of the efficiency of a structural member in absorbing impact energy. For an extruded aluminum crash can, SEA generally depends upon the topology of its cross-section. An investigation is carried out to determine the optimal cross-sectional topologies for maximizing SEA while considering manufacturing constrains such as, permissible die radii, gauges, etc. A comprehensive DOE type matrix of cross-sectional topologies has been developed by considering a wide variety of practical shapes and configurations. Since it is critical to include all feasible topologies, much thought and care has been given in developing this matrix. Detailed finite element crash analyses are carried out to simulate axial crushing of the selected crash cans topologies and the resulting specific energy absorption (SEA) is estimated for each case. Evidently, topologies with an outer and an inner ring joined together by a number of straight panels yields the highest SEA. Among single cell sections, hexagon and octagon are the most efficient topologies for crash energy management. Note that all conclusions drawn in this paper are based on CAE analysis results. The authors are currently pursuing physical testing to verify the CAE analysis results.