Step 2 – The loads

The chassis has many load cases applied to it. The one that we’re going to consider is a pure torsion test, which effectively is applying a pure moment to the front of the car through the suspension, which effectively pushes up on one side and down on the other to give a pure torque, which means there’s a lot of twist going on into the chassis. And the constraint is applied at the rear bulkhead through the fasteners we’ve mentioned before.

The stiffer the chassis, the better the car in terms of handling. The suspension design, operation, and adjustment can be compromised if the chassis isn’t stiff enough. A stiff chassis enables the suspension to work correctly and give the driver confidence in the handling. It’ll be responsive to small adjustments in the setting and tuning of the suspension at the racetrack.

A flexible chassis, on the other hand, will smother or subsume the results of any suspension adjustments predictable when handling on the limit of adhesion and probably spook the driver and be uncompetitive. Another reason is that it’s a non-destructive test and can be easily set up in the workshop. Teams can evaluate their latest chassis design or the results of any modifications in a repeatable manner and thus build up a database of knowledge and performance, which will also be useful in verifying computer models. The actual value of the load in this case is not important. We’re looking at stiffness measured as newton metres torque per degree of twist.