Numerical Study of Miro-Contact Surface Induced Hot Spots in Friction Brakes

This paper presents hot spot behaviors on the rubbing surface of disk-pad type brake by using coupled thermal-mechanical analysis technique. The height of micro-asperity on the rubbing surface is usually 2∼3 ${\mu}$m in practical disk brakes. Non-uniform micro-contacts between the disk and the rigid friction pads lead to high local temperature distributions, which may cause the material degradation, and develop hot spots, thermal cracks, and brake system failure at the end for a braking period. The friction temperatures on the rubbing surface of disk brakes in which are strongly related to the hot spot and thermal related wears are rapidly concentrated on the micro-contact asperities during braking. The computed FEM results show that the contact stress, friction induced temperature and thermal strain are highly concentrated on the rubbing micro-contact asperities even though the braking speed and force are small during the braking period. This hot spot may directly produce the slippage and various thermal wears on the brake-rubbing surface.

마찰식 브레이크의 미세 접촉면에 발생된 적열점 현상의 수치적 연구