Residual compressive strength of C/SiC composites after coupling continuous laser and supersonic flow: Coupled experimental-numerical investigation

To address the degradation of thermo‑structural integrity in C/SiC-based thermal protection systems under combined laser irradiation and aerodynamic heating, this study experimentally and numerically investigates the ablation behavior and residual compressive strength of 2D C/SiC composites subjected to continuous laser and supersonic flow. Tests were conducted in an arc‑heated wind tunnel to characterize ablation morphologies, followed by post‑ablation compression with full‑field strain monitoring via digital image correlation. A coupled ablation‑structural finite element model was developed, integrating an Arbitrary Lagrangian-Eulerian mesh‑updating scheme for ablation simulation and a thermodynamics‑based nonlinear damage constitutive model. The results reveal that ablation pit depth dominates the residual strength reduction, with a 27.9% decrease in failure strength as depth increases from 1 mm to 5 mm. Ablation pit diameter enlargement further aggravates strength loss by promoting local buckling, whereas morphological asymmetry shows limited direct influence. The proposed model predicts residual strength within 8.3% error across varied ablation profiles, providing an efficient simulation tool for damage‑tolerant design of hypersonic vehicle thermal protection structures under extreme thermo‑mechanical environments.