Non-Destructive Investigation of Bulk Residual Stress in Automobile Brake Pads with its Service Life

Abstract

Automobile brake systems transform kinetic energy into heat for the purpose of speed control. During this operation, rapid heating and cooling cycles cause the formation of residual stress in the brake pad backing plate. In this study, the relation between residual stress magnitude and the operation period is investigated to predict the service life of brake pads. Residual stresses are calculated related to longitudinal ultrasonic wave velocity variations which are measured non-destructively using cost effective and accurate immersion ultrasonic technique. Finally, a mathematical model is developed to predict residual stress in brake pad backing plates related to operation period.