There is a world-wide increase in the wearing of seat belts, brought about by laws regulating their design and use. With the improved safety this brings, there is also a change in the pattern of injuries which arise, in particular, from the steering system.

The wearing of a seatbelt changes the most likely injury site from chest to head and both research and proposed legislation recognize this fact (Ref 1).

Austin Rover uses computer-aided design techniques extensively in the design of its vehicles. Crash Victim Simulations can predict the nature of potential head/wheel impacts and rely upon design data to represent the wheel correctly.

Headform pendulum impacts are used to determine the stiffness characteristics of existing steering wheels.

By using a non-linear, finite element model, of a steering wheel, it is possible to predict its performance under pendulum impact conditions. The operation of crash victim simulation with this computerized finite element analysis allows an acceptable design to be developed prior to prototype construction. The technique allows material, construction and mass details to be varied in this process and can also be used to assess other properties such as strength and NVH.

One proposed form of legislative test adopts a pendulum impact but including a measure of impact pressure. Work on the finite element modelling of pendulum impacts with steering wheels is continuing so that this feature can also be simulated.