Thermal-mechanical Coupled Simulation And Life Prediction For A Ventilated Disc Brake

Brake is the main components of the vehicle brake system. The braking process is a typical thermal-mechanical coupling process. The coupled temperature and stress field analysis and calculation is an important part of brake design and its results are the important theoretical foundation in for selecting friction materials. The paper simulated the thermal-mechanical coupling phenomenon for a ventilated disc brake and predicted the thermal fatigue life of the disc.Firstly, a ventilated disc brake which is currently widely used for passenger cars was chosen as an example, the 3-D model of disc brake system was established using the software Catia, and was meshed using the software Hypermesh. The three-dimensional transient temperature field of heat conduction equation of the disc brake system was derived, and its heat input boundary conditions and convection boundary conditions were identified. And the thermal-mechanical coupled finite element model for braking system was established using the non-linear finite element software Abaqus. The transient temperature field, contact pressure and stress field of the disc are simulated during emergency braking. The effect of the heat due to friction caused by rotational movement of the heat generation and distribution, the coupling of the temperature, contact pressure and equivalent stress were taken into account during the course of numerical simulation. And the change of the heat transfer coefficient for each interface of the forced convection state of the brake disc was taken into account.Secondly, based on the results of the simulation of the thermal-mechanical coupling, the distribution of the transient temperature, contact pressure and stress field of the disc were analyzed under the condition of the time-varying moving thermal load and the convection heat transfer. With the alternating cycle of stress, the radial cracks which are common on the disc surface were studied. The thermal deformation of warping and the thickness variation of the disc were investigated. And according to the thermal deformation the disc influence on the contact state and contact pressure, the"hot spots"which are on the disc surface and hot judder were analyzed during braking process.Finally, the thermal fatigue life of the disc was predicted according to Manson-Coffin equation. The effect of the initial braking speed and brake pressure to the brake disc life were also studied.