Designing Anti-Roll Bars For a Formula Student car

[alextyler32]

Hi everyone,

I'm part of a Formula Student Team and we are trying to design and model the suspension system for our first ever car ready for the FSAE event in July, however we are struggling to identify what we actually need to do in order to get a good guideline as to the likely required spring rate of the roll bars. We've already designed the ARB system geometrically in order to help package the rest of the car, but now need to obtain required values for that design.

We've had a dig around what books were available to us and while lots explain how to obtain, for example, the material or dimensions of the ARB, none actually often explain how to obtain values for a new car: how to simulate the loads of the car in order to help give a guideline as to what sort of total roll stiffness for the car we need, like a car exhibiting braking/accelerating and cornering loads simultaneously.

As it's our first car, we have no previous data that can help give us a guideline value and nobody in the engineering department has direct experience of suspension modelling. I'm not expecting perfect results straight out the box, but I'd like to know what sort of stiffness range we are talking, as I also have to provide analysis for my dissertation.

Does anyone have any information on how we could go about simulating corner loads in order to help with the picking roll bar stiffness? Courtesy of Avon, we have some data about the tyre rates at various camber angles and pressures, but at the moment are unsure as to how we would implement these values (whether we apply the rate obtained from our predicted static camber value or whether we use the rate from the desired camber angle under heavy load).

Any advice is appreciated.

Thanks.

[pensio]

Rollbar act together with rollcenter hight and spring rates.
You need a corner weight calculator.
with rollbar you can adjust understeer/oversteer and overall rollstiffnes.
More information: cornerweights.blogspot.com