Comparative analysis of the thermal effect and wear suffered by a disc brake friction material subjected to Krauss bench tests with engine power variations and operating conditions.

ABSTRACT

Study aiming at comparative analysis of the thermal effects and wear suffered by the tribological pair of a brake system during tests performed by varying the motor power of a brake test bench. As is known, the brake mechanism is employed to control speed by converting kinetic energy and/or potential energy into thermal energy. This study aimed to analyze the operating parameters of a motorcycle disc brake system using a test bench based on the Krauss procedure, described by ABNT NBR 6143/1995. Experimental tests were conducted in two steps. In the first one, the test bench was equipped with a 3hp engine of motor power and a 2³ factorial design was used, in which the three control factors considered were deliberately changed at two levels each. To evaluate the performance of the brake system during the braking process, three response variables were analyzed simultaneously: final temperature, friction coefficient and brake pad wear. In the second stage, the motor power was increased to 10hp; The effect of contact pressure and sliding velocity factors, which were changed at four levels each, was analyzed. Here the brake pad wear response variable was analyzed. As a result of the comparative analysis, it was found that the tests of the second stage showed greater wear and heating of the friction material of the studied brake mechanism, which promoted a reduction of the coefficient of friction as a function of temperature increase, especially above 300 ° C, a phenomenon known in the literature as the braking fade effect.

Keywords
System of brakes; friction; thermal effects; wear; fade