POSSIBILITIES FOR THE USE OF METAL-HYBRID-STRUCTURES FOR VEHICLE CRASH LOAD CASES

A major challenge of lightweight construction of car bodies, particularly with materials with high density, such as steel, is the need to use a very low wall thickness. This makes the structures sus-ceptible to buckling, especially in crash load cases. The DLR’s institute of vehicle concepts therefore investigates the use of hybrid structures, for exam-ple by reinforcing the steel shell of a beam with lightweight cores. This leads to a higher stability of the structure, especially for the side impact or the pole crash, which results in a much higher weight specific energy absorption. In order to maximize the performance, a specific balance between several parameters such as the wall thickness, the material properties of the core and material properties of the shell, must be achieved. A multi-parameter optimization was therefore conducted, using LS-Dyna and LS-Opt, in order to maximize the weight specific energy absorption. Also, the impact of different materials on the performance of such structures was investigated. Possible uses for metal-hybrid structures are a rocker rail, or a door reinforcement, for example. They are also extensively used in the car body of a lightweight vehicle which is currently under de-velopment at the institute of vehicle concepts.