Frictional Characterization Of Grey Cast Iron Train Brake Block Using A Reduced Scale Dynamometer

The brake block is an important component that serves to slow down and stop the train. The safety of this transportation is very dependent on the reliability of this component. One of the important features of the brake block material is the coefficient of friction. The coefficient of friction of the brake block material must meet and match the requirements. The coefficient of friction of a material is measured using a friction test. Previous studies have shown that the friction coefficient of a material is influenced by braking conditions, namely contact pressure and friction speed. Many friction testing methods have been developed to study the characteristics of friction materials.  In contrast to previous studies, in this study, the frictional characteristics of gray cast iron brake blocks were evaluated using a reduced scale dynamometer. The friction test is carried out by pressing the brake block specimen to the surface of the rotating wheel. The specimen size of the brake block and carriage wheels is reduced to 1/4 of the original size. The friction test is carried out at a contact pressure of 0.15,  0.20, 0.25, and 0.30 (MPa) and the friction speeds of 3, 6, 9, and 12 (m/s). The results of this study indicate that the coefficient of friction of the gray cast iron brake block decreases with increasing friction speed and contact pressure

Effect of post curing method on flexural strength of composite friction brake

Friction brake material is important component in the braking system of the vehicles. These materials are usually made of asbestos and non-asbestos materials. Some non-asbestos materials use natural fibers as reinforcement and phenolic resin as a binder. The post-curing process is carried out by heating a material with specific temperature and time. During post curing, ammonia gas as the reaction of the phenolic resin and HMTA diffuses out from the friction brake material. The heating rate in post curing was supposed affecting process of removal ammonia gas from composite and it will affect mechanical properties of the composite. Therefore, this paper is concerned with effect of post curing method on the composite flexural strength. Composite specimen were manufactured by mixing the ingredients, preforming, hot molding and followed by post curing. Bending tests performed to determine the effect of post curing the flexural strength. The results showed that heating rate in post curing affected flexural strength of composite. Flexural strength of composite decreased with increasing heating rate. Internal defect that were formed during post curing decreased composite flexural strength