Evaluation and improvement of the strength of the brake disc

Generally brake disk needs to be replaced because cracks appeared, rather than reaching the wear limit. There are two forms; crack a crack generated in the friction surface; Another is a crack generated on the cooling ribs. Due to repeated heating and cooling; the friction surface soil crazing from near the friction surface thin layer at the development and expansion. Therefore, the occurrence of cracks in high-speed braking or under heavy braking conditions. Cracks on cooling ribs, the ribs would be due to thermal expansion caused by tension, compression and bending action. Such cracks in the high speed braking, heavy braking or long-time braking situation occurs. Among the characteristics of various factors affecting the intensity of the brake disc, the heat from the friction surface is a major influencing factors, pressure or centrifugal force. Tends to be a sudden decrease in the high temperature zone, the material strength of the brake disk. Anonymous, according to the temperature, thermal stress and brake frequently develop strength evaluation of the brake disc.
    In order to improve the strength of the brake disc, starting from materials and structural point of view of the strength of the brake disk. The results showed that the intensity of the special forged steel brake disk than twice as high as the strength of the cast iron brake disk. Other hand, the design will be little thermal stress of thermal strain in the radial pin brake disc set to half of the traditional type. Materials and structural improvements to improve the characteristics of the heat capacity, heat dissipation and thermal stress, the traditional narrow-gauge line train speeds up to 150km / h, make Shinkansen train speed reached 260km / h. Therefore it is necessary to develop the heat capacity and the most especially train speed, the braking deceleration, the braking force distribution ratio, and the degree of braking frequently matches the brake disc. To increase the intensity of the brake disc must improve the cooling effect. Since the desired device unsprung mass reduction, necessarily reduce the heat capacity of the brake disc; local heat lead to increased thermal stress, results weakened the role of improving the strength. For this reason, from a structural point of view must be starting to look for more effective heat dissipation method. Currently, research is the floating brake disk, but will be difficult to increase the thermal capacity. The most effective way to improve the heat capacity is used to the heat-resistant material. Carbon fiber in the heat than the special forged steel, but its drawback is the low intensity and high price. However, tend to show that the carbon fiber used as a high-speed vehicle brake disc material is hope.