Contact Pressure Distribution on Friction Interface for Flexible Drum Brake Systems

Analytical models used to design most of drum brake systems assume rigid body behavior of shoes and drum, resulting in sinusoidal pressure distribution in the friction interface. This approach leads to various limitations and sometimes incoherent results at typical applications since brake components are highly deformable and the contact pressure distribution plays an important role on the brake system efficiency. This study addresses a numerical analysis of drum brake pressure distribution, using Finite Element Method and considering shoes and drum as flexible bodies. The model validation from experimental procedure, where brake components were instrumented in an inertial dynamometer test. Once the pressure distribution can not be accurately measured, this research uses strain field measurements to calibrate the numerical model. This model is nonlinear, implying in convergence difficulties. However, the simulation technique presented here is a powerful tool to investigate the deformation of brake components and their influence in the friction forces and thus in brake system efficiency. The validation through strain field proved to be an interesting alternative to compare numerical models and experimental results.