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.
Abstract