Energy Absorption Behavior of Metal/Polymer/Metal Sandwich Crash Structures

Crash structures consisting of metal/polymer/metal (MPM) sandwich structures with a thermoplastic core exhibit a sufficient energy absorbing effectiveness, comparable or even better than metallic crash absorbers. In general, the crash structures have an unfavorable absorbing behavior at the beginning of the crash, which is indicated by high forces and small displacements. Because of this, the influence of inserted crash initiators (triggers) on the buckling mechanism was investigated using quasi-static and dynamic tests with different trigger geometries. As a result, a slit of 4 mm width decreased the peak force with about 50 % in the dynamic testing regime. A slit of 1 mm was found to be the most effective one for decreasing the peak force. The way the trigger works on the structure transferring it in a progressive buckling mechanism needs further investigation, due to a recorded double peak in the peak force area, which was not reproducible in different samples.