Whilst designing the wheel shape in Solidworks, there was uncertaintly around material choice and plate thickness. Within the university we had a selection of sheet metal, including steel and aluminium. Fortunately during research we stumbled upon a document concerning driver contol requirements by FSAE judge, Steve Fox.
Minimum driver applied forces, you should be designing/building/testing for:
- Steering System Lateral Force – The steering wheel and steering column should be able to withstand at least 660 N (150 lb) lateral (radial) force before failure.
- Steering System Torque – The steering system should be able to withstand a minimum of 100 Nm (75 ft lb) force, applied at the steering wheel, before failure.
Using these forces and FEA (Finite Element Analysis), the main plate was subject to numerous load tests with a variety of materials and thicknesses. The results for von mises stress and displacement observed in these load tests were studied to decide which material and thickness was most ideal.
Unfortunately this process was rushed and carried out with little thought of overall mass. Our selected material, Aluminium 5083 with a thickness of 6mm, resulted in a total assembly mass of around 800 grams. This was considerably heavier than alternative off-the-shelf steering wheels with electronic displays which tended to be around 400-500 grams in total. As mass is an incredibly important factor for Formula Student cars, the design would have to be revised and lightened before another wheel is made.