Abstract: In view of the degradation of reliability, braking performance and fuel economy of vehicle,caused by the heat accumulation in the in-wheel wet brake assembly during high-intensity braking, the finite element models for the assembly and its brake are built to analyze the thermal reliability of wet brake under the coupling of temperature filed and stress field during emergency braking or continuous braking. After the heat source system model of the assembly is established based on bond graph theory, the overall thermal reliability of the assembly under the coupling of thermal field and flow field during long-time high frequent braking is analyzed with consideration of the convective heat transfer of air and lubricant. The results show that under the common actions of stress field, temperature field and flow field, the thermal reliability of the wet bake assembly is significantly lowered during high strength braking and the results of numerical simulation and test verify the correctness of analysis methodology and the effectiveness of outcome

Key words: wet brake assembly, wet multidisc brake, thermal-stress coupling, thermal-flow coupling, reliability