STUDY ON THERMO-MECHANICAL INSTABILITY IN THE INDUSTRIAL BRAKES

摘要

This paper presents disc brake surface temperature field measurements, during emergency braking in real industrial conditions, by means of the thermovision infrared camera. The temperature field assessment enables the verification of the numerical modelling of the brake performance in the succeeding step. The experimental part of the research also covers tribological testing on the coefficient of friction between the friction brake material (brake pad) and steel (brake disc) in laboratory conditions on a tribotester which satisfied the similarity criteria with the mine winder hydraulic disc brake. The tribological characteristic of the friction couple, including the kinetic and static coefficients of friction, were determined for use in the finite elements analysis (FEA) of the brake thermo-mechanical instability (TMI) problem. In the numerical part of this work, the FE modelling technique was used to simulate the brake interface hot spotting and the axial disc distortion as a function of the geometrical and material properties of the brake elements and the brake's operational conditions. The critical speed above which TMI would occur was calculated for the analysed mine winder brake system. A FE method was used to find the temperature distribution and the resulting thermal stresses and distortions in the brake discs. The disc division into various numbers of sections was numerically tested for the division's effect on thermal stress reduction and axial distortions.