Methodology to Analyze Thermal and Mechanical Stresses in Friction Material

In engineering development, simulation methods are frequently used to perform thermal and mechanical stress components analysis. In brake systems, where the components are exposed to mechanical and thermal loads, the numerical analysis is very helpful. Once a numerical model for brake assembly is available, it will be possible to understand the effects of successive brake applications on the temperature distribution in drum brake's friction materials. This is a fundamental aspect to determine, for instance, the thermal stress distribution which is related to the warming and cooling of the brakes. In this work, an analytical solution to calculate stabilized temperature was used to establish a heat flux through a pneumatic S cam drum brake's friction material applied to a numerical model in a finite element analysis. After including the effects of the riveting process and the warming in one of the 17 t bus front brake lining, areas where the stresses vary with considerable amplitudes during temperature increase were identified. The study has indicated that friction material can be submitted to cyclic loads that can cause damage accumulation. These areas have corresponded to local regions of brake linings where historically failures occur during development tests. Also, it was possible to compare results from numerical model to vehicle's experimental data and understand its proximity to real braking events. By the application of the methodology and using the numerical model proposed in this work, it will be possible to contribute considerably for a more accurate design of the friction material.