Temperature Prediction Method of Heavy-Haul Trains Tread Braking Based on Non-Uniform Contact Pressure Between Wheel and Brake Shoe

During the tread braking of heavy-haul trains, the frictional heat generated between the wheel and brake shoe directly impacts their abrasion and service life, thereby influencing the safety of train braking operations. It is necessary to effectively predict the tread braking temperature distribution of the of heavy-haul trains. The wheel-brake shoe interface of heavy- haul trains tread braking involves intricate geometric contact and frictional characteristics, leading to a complex distribution of frictional heat on the wheel and brake shoe that changes with variations in contact and frictional states. Existing methods have demonstrated limitations in effectively predicting the complex distribution of frictional heat.

To address this challenge, a sophisticated approach had been developed based on the actual profiles of the wheel tread and its corresponding brake shoe profile. This method modified the calculation of frictional heat flux density by considering the contact state between the wheel and brake shoe, enabling the simulation of frictional heat characteristics at various contact positions along the wheel and brake shoe interface. Furthermore, through the integration of finite element methods with thermodynamic principles, a novel temperature prediction method had been proposed. This method took into account the non-uniform contact pressure between the wheel and brake shoe, which was verified by bench test, and the temperature field prediction of the wheel and brake shoe under different braking conditions was realized.

Building on this foundation, a comprehensive analysis had been conducted to compare the results obtained using the proposed method with those derived from traditional method (which assume uniform contact pressure). The results demonstrated that the proposed method was capable of more accurately predicting the temperature evolution and distribution characteristics of the wheel and brake shoe. In contrast, traditional methods may effectively predict the highest temperature of the wheel, while often struggle to accurately reflect the highest temperature of the brake shoe or capture the actual temperature distribution of both components during the braking process.

Therefore, in analyzing tread braking temperatures and associated subjects (thermal stress, thermal cracking, and thermal fatigue, et, al) in heavy-haul trains, it was crucial to consider the non-uniform contact pressure resulting from the actual contact state between the wheel and brake shoe. This consideration ensured the reliability and accuracy of the results, ultimately enhancing the safety and efficiency of train braking systems. In conclusion, the development of this method represented a significant advancement in the field of train braking safety. By accurately predicting temperature distributions and considering non-uniform contact pressures, the proposed method held promise for improving the design and operation of braking systems for heavy-haul trains, ultimately contributing to enhanced safety and reliability in rail transportation.