Numerical prediction of thermal contact resistance of 3D C/C-SiC needled composites based on measured practical topography

The 3D C/C-SiC composite is a kind of widely used material in thermal protection system or other functional parts of the hypersonic vehicles. This paper conducts numerical simulation to predict the thermal contact resistance of the 3D C/C-SiC needled composite pairs. The practical surface topography is measured by a 3D optical microscope named Bruker Contour GT-K, and the rough surfaces for simulation are reconstructed in ANSA software with the help of Python code. The measured arithmetical mean roughness (Ra) of the two specimens are 12.04 μm and 11.75 μm respectively. The prediction is divided into two steps, static analysis for revealing the contact spot distribution of the contact interfaces, and thermal analysis for the temperature distribution of the contact interfaces to calculate the thermal contact resistance. Both two steps are finished with Abaqus. The prediction results show that actual contact area only occupies a small part of nominal contact area (when pressure is 5.52 MPa, the actual contact area just accounts for 7% of the nominal contact area), and the dependency curve approximately shows linearity between the proportion of actual contact area to nominal contact area and loading pressure. Besides, thermal contact resistance decreases with an increase in loading pressure and temperature. Thermal contact resistances of the studied composite materials are in the order of 6 × 10⁻⁴–1.2 × 10⁻³ K·m²·W⁻¹.