Evaluation of the Thermal Expansion Effect of the Carbon–Carbon Composite Surface on Contact Interaction with a Ring-Shaped Sample

Carbon–carbon composite materials (CCCMs) are used in brake systems and in movable sealing joints, since they can have both frictional and antifriction properties, depending on their structure. In recent studies, data were obtained on the thermal properties of various CCCMs and the coefficient of friction in a pair with various counterbodies as a function of temperature. In this case, the nature of the dependences of the friction coefficient and the coefficient of linear thermal expansion on temperature is similar and has close critical points. The paper investigates the contact interaction of a heated heat-insulated annular punch with a half-space, the thermal expansion coefficient of which depends on temperature. Analytical expressions are obtained for calculation of the contact pressure and the penetration of the punch for various temperature distributions over the contact area. To take into account the uneven heating of the contacting surfaces, the temperature distribution under the annular punch was calculated during its frictional interaction with the elastic half-space. The case of temperature distribution during heating from spinning friction, which is typical for tribological tests and operation of interfaces made of CCCMs, is considered. It is established that in the considered case the temperature increases from the inner radius of the annular punch to the outer one. The joint effect of the ring width and temperature distribution on the value of contact pressures is studied. Calculations show that taking into account frictional heating is more important for narrow punches, while the minimum pressure in the contact area can significantly decrease at a fixed value of the external load.