Investigation of coefficient of friction at the interface of automobile brake pads using Greenwood-Williamson contact model and novel test rig

Abstract

Different brake pad materials are produced, each with their unique composition in the recent past, yet performing the same task and claiming to be better than others. The article provides references for different automotive brake pads subjected to various operating conditions. The present investigation develops an analytical approach for estimating COF and contact radius for different disc-brake pads, which can be used to design an efficient automotive brake pad-disc system under the given load and rotational speed. The coefficient of friction at the pad-disc interface is investigated considering Greenwood Williamson (GW) model and developed novel friction test rig. A MATLAB program along with FFT was developed to simulate the surface topography of the contact interface during the braking process aiding the estimation of contact radius. Surface topography of tested brake pads has been analyzed using an infinite-focus-microscope to verify contact radius. At last, the reference is verified by an experimental investigation using a developed test rig and considering operating parameters.