A SCA-based concurrent multiscale thermo-mechanical model for transient thermal ablative and mechanical damage properties of SiFPRCs

Accurate numerical simulation of the ablation process in silica fiber-reinforced phenolic resin composites (SiFPRCs) is critical for advanced thermal protection applications. However, conventional dual-scale finite element (FE²) methods incur prohibitive computational costs when capturing the strongly nonlinear responses induced by multiple dissipative mechanisms during thermochemical ablation. To address this issue, we propose a dual-scale framework (FEM-SCA) that integrates the finite element method (FEM) with self-consistent clustering analysis (SCA). At the macroscopic level, FEM captures the overall thermo-mechanical response, while nested mesoscale representative volume elements (RVEs) are solved using the SCA to capture dissipative processes, including heat radiation, phenolic resin pyrolysis, thermal blocking, silica fiber phase transitions, carbon-silicon reaction, and mechanical degradation. A staggered incremental scheme enables efficient transient coupling across scales. Validation against FE² benchmarks demonstrates that FEM-SCA reproduces thermal conduction and pyrolysis behavior with <5 % error, while reducing computational cost by over two orders of magnitude. The proposed framework offers a computationally efficient and physically grounded approach for simulating ablation in woven composites.