An investigation of initial topography on thermoelastic behavior of brake disc under thermal load

Abstract

Friction hot spot is an important problem of automotive disc brake. Its mechanism is not clear currently and the related theories are divergent. Thermal Buckling theory is one of the most influential theories, but the influence mechanism of the initial topography has not been fully studied. In this paper, the influence of initial topography on thermoelastic behavior of simplified brake disc under independent thermal load are studied by experiment and simulation to explore the generation mechanism of disc buckling. The experiment with oxy-acetylene flame as thermal load is designed, and two discs with different initial topography are tested. The buckling process and deformation evolution are studied, and it is found that the initial topography has an influence on the buckling mode. In order to reproduce the 4-order buckling phenomenon in experiment, a new nonlinear thermal buckling finite element (FE) model of disc with initial topography is proposed and solved by using modified Riks algorithm. The accuracy of the proposed model is higher than the usual linear thermal buckling model. The influence factors of initial topography are also discussed. It is found that the order components of the initial topography have a great influence on the buckling order, and the amplitude of initial topography has an important effect on the critical buckling temperature. This study can offer valuable reference to revealing the mechanism of thermal buckling mode and waviness distortion.