Effect of disc hardness on MR brake performance

The online control of frictional force using MR fluid makes Magneto-Rheological (MR) brake an attractive option to replace the conventional disc brake. However, initial experiments on MR brake showed deterioration in the braking performance with time. To understand the science, the disc was investigated using the 800 × microscope and concluded wear of disc as the cause of brake-performance deterioration. To overcome this problem, disc with higher hardness was proposed. Initially experiments using “block on disc setup” were performed. The blocks of 15HRC, 30HRC, 50HRC and 57HRC hardness were used. The performance of the experiment was evaluated by measuring the weight loss of the blocks before and after the tests. To validate the finding of the block on disc experiment, experiments were performed on developed MR brake test setup for discs having hardness of (i) 15HRC (minimum hardness) and (ii) 63HRC (minimum hardness). The results observed from experimentation on MR brake and images of discs capture using microscope are presented.