Abstract
As opposed to the traditional method of development, the present level of the automotive technique, beyond any doubt, requires new techniques and methods in the brakes development. Now a days it is a necessary to ensure that the basic elements of the development process i.e. design engineering, calculation and testing are conducted in highly intregrated environment. The digital brake model is seen as the way to introduce simultaneously different variants of the geometry, operating conditions of the brake, and to ensure to research complex process during braking before the first physical prototype has been made. No doubt that analysis of termomechanical phenomena during braking is extremly complicated because when two bodies slide against each other, frictional heat is generated and the resulting termoelastic deformation alters the contact pressure distribution. Above a certain critical speed a nominally uniform pressure distribution is unstable, giving a way to localization of load and heat generation. That is why hot spots is occured at the sliding surfaces. Hot spots can cause material damage and wear and are also source of undesirable frictional vibrations, known as hot judder. Digital brake model is offered possibility to simulate anyone single brake application (for predetermined initial conditions). During digital model braking changes of kinetic energy, rotational speed, pressure application and contact area between disk and disk pads are being measured.
The methodology for determination of the level of thermal loads in the contact areas or so called "hot spots" is presented in the paper. It is not only that in such a way the instantaneous temperature value in a discrete moment should be determined, but also the variation of it should be followed during the whole braking cycle so as to super-pone it with the precedent and the next thermal and/or mechanical loads in the contact area. Now, it is possible to "enter this restricted zone" by means of analysing the braking cycle during brake tests on the virtual test bench. In such a way it becomes possible to discretize the braking cycle and thus to follow the interrelations between the variation of influencing factors and the resulting thermo-mechanical effects. There are sets of results available to enable identification of contact loads or thermomechanical loads and these are obtained under real test conditions for the same operation conditions of the real and the virtual brake. It is understood that the same brake has been used in both real and virtual environment.