A Study on the Contact Pressure and Thermo-Elastic Behavior of a Brake Disc-Pad by Infrared Images and Finite Element Analysis

To understand the tribological characteristics of a frictional brake system, it is very important to measure the contact pressure between the brake disc and pads. But until now there have been no direct methods by which to measure the contact pressure. In this study, an attempt to indirectly estimate the contact pressure is proposed. Infrared thermal images and finite element analysis were used as tools. For the thermo-elastic finite element analysis, uniform, linear, quadratic, and quartic heat flux profiles in the radial direction were applied on the disc surface. Thermal and stress fields were obtained under various conditions in the disc fixing holes and on the contact faces of the two half discs. From the numerical results, it was found that the effect of the boundary conditions on the magnitude of thermal stress was about 10%. Numerical temperature data in the radial direction could be curve-fitted to functions with the same order as the heat flux profiles. The coefficients of correlation of the curve-fittings were more than 0.91. It could be concluded that using temperature profiles obtained with an infrared camera, contact pressure distributions on the disc surface could be inferred.