Conductive heat transfer across a bolted automotive joint and the influence of interface conditioning

As part of commercial vehicle disc brake heat dissipation research, thermal contact resistance (TCR) across a bolted joint is analysed. Studies include new and slightly corroded interface surfaces. Measurements show that corrosion approximately doubles TCR, decreasing conductive heat dissipation, leading to higher brake temperatures. To reduce TCR, two methods of interface conditioning are investigated. The application of thermal conductance paste and the use of a thin aluminium gasket at the interface have similar effects, reducing TCR by over 80%. The paper deals with the methodology of measuring TCR and defining its relationship with the change of interface pressure, temperature and interface conditioning. This approach ensures results of a generic nature applicable to a variety of bolted joints.