A wear diagnosis for brake pads by evaluation of contact interface

Abstract

This work examined a used brake pad and another brand new one to compare their contact shape and contact area. Surface roughness measurement and ultrasonic scanning were used to study the contact interface. The 2D maps show the variation in the contact shape, which indicates that the used pad is unevenly worn to a significant extent. The results may suggest the improved pad design and provide the timing of replacement for a brake pad. The contact area shows an increasing trend under different applied forces and the area matrix gives useful information about the degree of wear. Contact pressures were also calculated by the combinations of image analysis software and ultrasonic technique. The contact pressure varies from 0.17 MPa to 3.4 MPa and maps of the distribution of the pressure contour are also shown.