Thermal Analysis of Thermal Spray Coated Gray Cast Iron Brake Rotor

Braking is a process which transform the kinetic energy of the rotor into heat energy. During the braking phase, the frictional heat generated at the interface rotor–pad can lead to high temperatures (> 600 oC). In long-term frequent use of braking, increased temperature causes disc distortions, heat cracks, and causes degradation of the pad material. This creates a risk in the reduction of rotor-pad interface friction and loss of brake performance under safe driving conditions. In this study, the thermal monitoring of the thermal spray coated rotor was investigated and the variation of the friction coefficient and wear related thickness were measured. In addition, changes in torque forces at increasing temperatures were also evaluated.

Interface Direct Shear Tests on JEZ-1 Mars Regolith Simulant

The mechanical behaviors of Martian regolith-structure interfaces are of great significance for the design of rover, development of excavation tools, and construction of infrastructure in Mars exploration. This paper presents an experimental investigation on the properties of a Martian regolith simulant (JEZ-1) through one-dimensional oedometer test, direct shear test, and interface direct shear tests between JEZ-1 and steel plates with different roughness. Oedometer result reveals that the compression and swelling indexes of the JEZ-1 are quite low, thus it is a less compressible and lower swelling soil. The cohesion and adhesion of JEZ-1 are lower than 5 kPa. The values of the internal friction angle range from 39.7° to 40.6°, and the interface friction angles are 16.7° to 36.2° for the smooth and rough interface. Furthermore, the direct shear and interface direct shear results indicate that the interface friction angles are lower than the internal friction angles of JEZ-1 and increase close to the internal friction angles with increasing interface roughness.