Facial fracture probability secondary to steering wheel impact

This paper describes the techniques used to conduct: (i) quasi-static and dynamic tests on the steering wheel; and (ii) intact fresh human cadaver head impact tests at the unsupported rim (USR) location on both an energy absorbing (EA) and a standard (STD) steering wheel. The most important conclusions are as follows: (1) The junction of the lower spoke and rim (LSR) is stiffer than the center of the USR under quasi- static loading for both the EA and STD wheels; (2) The interface force- time response at the wheel rim typically exhibits bimodal behaviour. The first force peak appears to be a function of wheel rim inertia. The second peak appears to be largely driven by the force-deflection behaviour of the wheel; (3) At low impact velocities, the first peak is smaller than the second one; (4) Interface force was determined to be the most likely variable that correlates with zygomatic bone fracture. A force of 1525 N corresponds to a facial fracture probability of 50% for the EA wheel at the LSR location; (5) No fractures were documented at the USR location on the EA wheel at velocities up to 6.7 m/s; and (6) additional tests are required to completely describe the probability distribution for the STD wheel at the LSR and USR locations. For the covering abstract of the conference see IRRD 864606.