Smart Impact Management Devices: Experimental Validation of Crush Response of Rapidly Expanded Aluminum Honeycomb

A major limitation of current dedicated impact energy management structures and passive devices used in the transportation industry is that their starting volume is their maximum volume, i.e. they dissipate energy by crushing or stroking from a larger to a smaller volume. Since they occupy their maximum volumes in their uncrushed-as-installed state they occupy space that is then only functional in an impact and is otherwise wasted. This limitation has led to the proposal of a class of "smart" impact energy management devices, based on unexpanded aluminum honeycomb (HOBE), that initially occupy a small volume and based on sensor input are rapidly expanded to a much larger crushable volume (nominally 75 times greater) just prior to or in response to an impact. Energy management devices based on this technology, should this technology successfully pass through the many steps needed to prove its viability, would thus allow empty space to be left adjacent to them for operational clearances, serviceability and repair functions, etc. which spaces would yet be fully utilized, due to the expansion of the device, for impact energy management. This paper documents the second portion of an experimental exploration of the viability of this technology. The specific goal of the here-in documented portion of the test program was the demonstration that the crush response of the rapidly expanded honeycomb is comparable to that of the standard pre-expanded commercial product.