An Efficient Sequential Approach for Simulation of Thermal Stresses in Disc Brakes

In this paper an efficient approach to simulate thermal stresses due to frictional heating of disc brakes is presented. In the approach thermal and stress analysis are performed sequentially. The frictional heat analysis is based on the Eulerian method, which requires significantly low computational time as compared to the Lagrangian approach. Complete three-dimensional geometries of a disc and a pad are considered for the numerical simulations. The contact forces are computed at each time step taking the thermal deformations of the disc into account. The nodal temperature history is recorded at each time step and is used in sequentially coupled stress analysis, where a temperature dependent elasto-plastic material model is used to compute the stresses in a disc brake. The results show that during hard braking, high compressive stresses are generated on the disc surface in circumferential direction which cause plastic yielding. But when the disc cools down, the compressive stresses transform to tensile stresses. Such thermoplastic stress history may cause cracks on disc surface after a few braking cycles. These results are in agreement with experimental observations available in the literature.