Numerical calculation of high temperature thermal response of 3D braided carbon/phenolic composite

Abstract

In order to accurately calculate the thermal response of 3D braided carbon/phenolic composite under high temperature, the matrix and fiber bundle of composite were established separately and a mathematical model was adopted based on the conservation of energy and mass, changes in phenolic matrix density as well as material thermal properties in pyrolysis process. The distributions of temperature field and pyrolysis degree were predicted, and the mass loss rate, the formation position and the thickness of char layer were shown. The results show that the temperature distribution of the 3D braided carbon/phenolic composite is extremely uneven, and the matrix temperature on the heating surface is significantly higher than the fiber bundle temperature, while the vertical fiber bundle temperature inside the material is higher than the matrix temperature. At the beginning of heating, the char layer is not generated immediately, but requires a transition period， during which the average thickness of the char layer is zero. The calculation of thermal response can better understand the behavioral characteristics of the composite, and provide reference and basis for the design and optimization of the thermal protection materials.

Keywords

• 3D braided composites
• temperature field
• thermal response
• thermal protection system
• numerical calculation