Finite element analysis of frictionally-excited thermoelastic instability in 3D annular disk

The frictional heat generated during braking causes thermoelastic distortion that modifies the contact pressure distribution. If the sliding speed is sufficiently high, this can lead to frictionally-excited thermoelastic instability (TEI), characterised by major non-uniformities in pressure and temperature. In automotive applications, a particular area of concern is the relation between thermoelastically induced hot spots in the brake disks and noise and vibration in the brake system. Numerical implementation of Burton's perturbation analysis for thermoelastic instability in a two-dimensional model provides an extremely efficient method for determining the critical speed in simple sliding systems. In this paper, the two-dimensional model has been extended to an annular three-dimensional disk model in order to consider more realistic brake and clutch geometries and to provide more accurate critical speed. The results show that the eigenmodes exhibit focal hot spots along the circumference on each side of the disk and the thin disk is more stable than the thick disk when both disk thicknesses are below the optimal thickness.