Thermo-Chemo-Mechanical Coupled Response Analysis of Isotropic Short Carbon Fiber-Reinforced Rubber Matrix Composites under High-Temperature Ablation

Abstract

Carbon fiber-reinforced rubber matrix composites (CFR-RMC) exhibit excellent deformability, elastic recovery, and ablation resistance, enabling them to overcome the deformation limitations of rigid thermal protection materials. However, reliable predictive models for their thermo-chemo-mechanical coupled response under high-temperature ablation remain lacking. The novelty of this paper lies in constructing a fully coupled thermo-chemical–mechanical framework that links pyrolysis kinetics, temperature- and carbonization-dependent properties, and mechanical equilibrium for isotropic short CFR-RMC. The model framework was validated using measured back temperatures as well as the total deformation induced by ablation and thermal expansion, achieving relative errors below 0.46% and 5.2%, respectively (at 2 MW/m²). Numerical results show that significant thermal stress concentration occurs within the pyrolysis zone, which induces cracking and spallation of the char layer. Reducing the thermal conductivity of both the virgin material and the char layer can simultaneously improve thermal insulation performance and mechanical reliability. Sensitivity analysis indicates that ablation heat flux and virgin thermal conductivity are the dominant influencing factors. The proposed model provides reliable prediction and theoretical support for the design and optimization of high‑performance flexible thermal protection composites.