Consistency of Frictional Temperature and Wear on Indicating the Critical Thickness for Disc Brake Replacement by Finite Element Model

Reduced thickness reduces the heat dissipation capacity of the brake disc and its mechanical strength, triggering a series of critical faults and failures. To determine the critical thickness for disc replacement, a transient analysis for contact problem of disc brakes with frictional heat was performed using finite element method. To analyze the effect of disc thickness on the frictional heat generation, different brake disc models were developed with disc thicknesses of 5.0 mm, 5.5 mm, 6.0 mm, 6.5 mm, 7.0 mm, 7.5 mm and 8.0 mm. Subsequently, the developed disc models were evaluated under 2210 N, 2875 N and 3538 N braking forces and 884 rpm, 1149 rpm and 1415 rpm rotational speed of the disc. The numerical simulation for the thermoelastic behavior of disk brake was obtained in the repeated brake condition by Finite Element Analysis package of SolidWorks. The results showed that increasing the braking force from 2210 N to 2875 N, 2875 N to 3538 N and 2210 N to 3538 N resulted in 28.45%, 33.62% and 52.5% deformations respectively. Subsequently, increasing the rotational speed of the disc from 884 rpm to 1149 rpm, 1149 rpm to 1415 rpm and 884 rpm to 1415 rpm resulted in 69.57%, 17.23% and 74.8% deformations respectively. Though, the differences in successive forces is the same, the percentage deformation was not the same but rather a decline in the increase. In the case of the ultimate stress, the application of 884 rpm, 1149 rpm and 1415 rpm speeds at the same braking force of 2210 N yielded 1.327 x 1011 N/m2, 2.069 x 1011 N/m2 and 2.072 x 1011 N/m2 ultimate stresses respectively. Increasing the rotational speed of the brake disc from 884 rpm to 1149 rpm and 1149 rpm to 1415 rpm resulted in 35.86% and 0.14% ultimate stress respectively. The overall results have shown that, under the same condition of treatment; effect of braking force > effect disc rotational speed > effect of disc thickness. There was a sharp drop in temperature at all the radii points where readings were taken and this could be due to initial heat transfer from the disc to the pad just at contact. The minimum thickness for optimal heat and wear reduction 6.7 mm. The present study can provide a useful design tool and improve the brake performance of disk brake system.