- #1

Kozy

- 141

- 7

For the past 6 years I have been working (on and off) on a vehicle brake system simulation tool. It takes a lot of inputs about the car and the brake components, along with a rate of maximum lateral acceleration which is used to determine the amount of grip available.

The model then solves for the point of front tyre lock up, a point which of course varies depending on all the factors involved, so for example if you add front bias to the brake force distribution, the overall brake force drops due to earlier front wheel lockup, the rate of acceleration therefore changes, as does the load transfer, stopping distances etc etc.

It provides a detailed analysis of the brake system, some the results include pedal force (accounting for booster assistance calculated from inlet manifold pressure and diaphragm area), load transfer, rate of acceleration, stopping distance, 'dynamic bias' (where 0% is always all four wheels locking simultaneously and 100% is no rear brake force at all) and energy dissipation.

There is also an input for engine power, which when combined with the weight and grip inputs, is used to model a rate of positive acceleration. From this information, it was also possible to work out the relative heating and cooling of the brake discs, based on the amount of energy absorbed by each one, the mass, material, cooling surfaces and also the rate of acceleration between corners.

An oval test circuit is then modeled, with the car accelerating, braking and cornering at rates congruent with the inputs, so for instance a car with more grip will corner faster needing to slow down less for the corners, but also brake harder in a shorter distance. One with more power will accelerate to a higher speed, and need more distance to slow down for the corner.

I am fairly happy with this now, but I am in need of some knowledgeable people to test it out and point out any obvious flaws. Also, I would like to hear any advise on anything that is not clear, as I would like this to be an easy to use tool for anyone looking to upgrade their brakes, not just for engineers with a lot of background knowledge.

The tool can be found here. Any feedback welcome, especially if you find problems / glitches as I need to iron those out!