Development of composite brake linings in heavy duty trucks

Materials for friction used in brakes should fulfill many requirements, such as stable friction performance in all conditions, lower change in the friction coefficient, high wear resistance and low wear rate. In this study, three different compositions were produced to investigate the effects of each composition and its manufacturing parameters. Three different compositions, which are called standard, fly ash and sisal fiber mixture, were produced to be compared with existing commercial heavy duty truck brake lining. These compositions were homogeneously mixed and hot molded at different pressures and temperatures. The post-curing effect was also investigated in some of the samples. The density and hardness of the samples were analyzed, the wear and friction tests were performed according to the JISD 4411 standard in a JF151 friction tester. Weight losses at high temperatures were determined by TGA tests. The abrasion and normal surfaces were examined by SEM analysis, internal shear strength and compression strengths were measured. With the field dynamometer test, the appropriate sample was produced under real conditions and tested on a dynamometer. The results showed that, fly ash samples that produced 180˚C - 30MPa without curing provided the closest wear-friction properties with the heavy load truck lining. In the TGA test results of this sample, the decomposition temperature was found as 450˚C which also similar to the commercial lining. This fly ash composition has 40% fly ash, 20% phenolic resin, 20% rockwool, 10% graphite, 5% MoS2, 5% cashew and it is highly recommended as the most suitable alternative for use in heavy-duty trucks. Key Words: Composite truck brake linings, friction, wear, fly ash, sisal