An Assessment of Add-on Energy Absorbing Devices for Vehicle Crashworthiness

An alternative approach to vehicle crashworthiness improvement by inserting add-on nonstructural energy absorbing (EA) devices in the unutilized space in series with existing load paths is studied conceptually. Vehicle-barrier impact simulations are conducted to determine the energy absorption and crushable space requirements for the add-on devices. Based on the experimental data available in the literature, a number of materials are identified as being capable of meeting these requirements. Simple tubes and honeycombs in axial crushing mode are found to be more effective as add-on EA devices than complex devices such as inversion tubes. Foam filling of primary structural members in bending mode is found to be less effective in increasing energy absorbing capacity than add-on EA devices. While the study indicates a theoretical assessment of these devices, physical limitations may inhibit their usefullness. In particular, many of the devices are highly directional in nature.