Papers by Author: Abd Rahim Abu Bakar

Abstract: This work investigates the effect of road grit particles and material compositions on disc brake squeal noise. Three different Non Asbestos Organic (NAO) brake pad samples and road particles with a size range between 400 μm to 500 μm are used in the squeal experiment. The relationship between the existence of road particle with the noise occurrence were studied through the change in pressure level, friction coefficient (CoF), sound pressure level (SPL) and material composition. The material compositions were analyzed before and after squealing condition using energy dispersive X-ray analysis (EDX). Result has shown the road particles contribute to the emission of squeal noise and the increasing of some material composition of brake friction material components.

Abstract: Drum brake squeal is one of the most common and annoying types of brake noise and it usually falls in the frequency range between 0.5-16 kHz. Brake squeal continues to confront vehicle manufacturers where it not only leads to significant increase in the warranty costs but also may affect customers perception on quality of the vehicle. Thus this paper attempts to prevent drum brake squeal by means of lining modifications. In doing so, finite element method is first employed and squeal noise will be then predicted using complex eigenvalue (CE) analysis. A good lining modification should be able to stabilize the drum brake assembly by shifting or reducing positive real parts toward zero or negative real parts in the eigenvalue analysis. Finally, laboratory squeal tests are conducted on the four proposed modifications to verify its effectiveness against squeal.