Improved Drum Brake Performance Prediction Considering Coupled Thermal and Mechanical Effects

This paper presents a methodology for predicting drum brake performance using FEA (finite element analysis) models considering both the mechanical-structural compliance and thermal effects. The methodology for brake torque prediction with FEA models considering the structural flexibility of the brake components alone has been established [1]. The frictional heat generated during braking causes thermoelastic distortion that modifies the contact pressure distribution at the drum-lining interface. In order to capture this thermal effect, a transient thermal analysis is conducted to predict the transient temperature distribution on the brake components. In the thermal analysis, the heat generated at the drum and lining interface is based on the pressure distribution from the compliant mechanical model. Also, the mechanical properties of the brake components as well as the lining friction are dependent on the temperature distribution. The mechanical and thermal models are thus tightly coupled. During a braking event, the system goes through a series of geometry and temperature distribution changes. For each time segment, the brake torque can be calculated based on the methodology presented. With that, the vehicle's stopping distance can be calculated. Inherent to the analytical implementation of this procedure is the ability of the FEA models to accurately simulate the thermal and structural behavior of the drum brake system. These structural and thermal FEA models form the core of the process to simulate entire braking event. The paper describes the FEA model development and validation process as well a case study, which implements an adaptation of the general procedure. This simplified procedure lends itself to effective product development support.