3C22 Wear and Tear Analysis for High Friction Coefficient Synthetic Brake Shoe in Freight Train Under Harsh Conditions(Safety-Vehicle)

Abstract

The friction heat generated by twenty thousand tons freight trains during emergency braking process or long ramps velocity modulation braking process affects brake shoe was researched by ANSYS and scanning electron microscopy. Also, the limit amount of wear about shoe was calculated theoretically. The temperature and stress fields of shoe was simulated by ANSYS, friction and wear state of shoe's friction surface was watched with scanning electron microscopy. The results show that the highest temperature of non-wear shoe is 206.2℃ in the 28^<st> second of the whole emergency braking process, the maximum stress is 15.4Mpa in the 32^<st> second. Yet, the highest temperature and maximum stress appears at the end of the long ramps velocity modulation braking process, which is 651.1℃ and 62.4Mpa separately. When the wear reaches certain extent, the highest temperature of shoe is more than 900℃. During the braking process due to fiber breakages and the base material drops caused by fiber fracture, the friction surface of shoe forms defects and tiny hot cracks. Under the condition of the gradient is -12‰ and the limit speed is 80km/h the amount of wear on the brake shoe reaches 20.96mm per ten thousand kilometers. Reducing compression modulus and increasing the thermal conductivity of the brake shoe moderately both reduce the heat storage for brake shoe. Also, improving the adhesive strength between reinforced fibers and the substrate can avoid emerging the defects and cracks on the friction surface premature.