Thermal State of Automotive Brakes after Braking on the Road and on the Roll-Stand

The temperature influences significantly the braking effectiveness. The paper describes consistency criterions of the brake thermal state in road braking conditions and on the roll-stand. As a result of the vehicle motion simulation, the time histories of the heat fluxes generated on the friction surface of the front and rear disc were determined. They were used as an input data for the model of the heat transfer process in disc brakes. The problem was solved by the use of the finite element method. Time histories of temperatures on the friction surfaces and in the material of the disc were calculated. As a preliminary consistency criterion of the brake thermal state in road and roll-stand braking conditions, a balance of the energy cumulated in the brake rotor was assumed. As the most reliable consistency criterion an equality of average temperatures of the friction surface was assumed. The presented method allow to simulate on a roll-stand the thermal state of automotive brake which is observed during braking in road conditions. Basing on the method it is possible to calculate the test velocity, braking time and brake force.