Tensile‐after‐ablation progressive damage and the failure mechanism of 2.5D woven composites with crack pores

Abstract 2.5D woven structures are of interest in new thermal protection systems for their excellent interlayer properties and structural stability. In this paper, dense (CDP) and lightweight (CLP) carbon/phenolic 2.5D woven composites were prepared. Quasi‐static tensile experiments were performed on the specimens before ablation (TCDP‐0, TCLP‐0) and after ablation for 30 s (TCDP‐30, TCLP‐30). A quarter macro–meso hybrid model that takes into account the degradation of material properties after ablation and ablative crack pores was innovatively proposed. The predicted tensile elastic modulus is within 9% error from the experimental results. The results show that TCDP‐30 and TCLP‐30 have rapid damage expansion and lethal injury at smaller displacements than the pre‐ablation specimens. The displacement of the maximum load point of TCDP‐30 is 38.7% lower than that of TCLP‐30. The forms of damage in TCDP‐30 are dominated by matrix fragmentation and matrix cracks. The damage forms of TCLP‐30 are dominated by debonding and delamination. Highlights Micro‐CT was used to collect matrix fabrication defects and ablative crack pores defect. A quarter macro–meso hybrid model that takes into account the degradation of material properties after ablation and ablative crack pore was innovatively proposed. The tensile failure mechanism of the material after ablation was revealed by the combination of experiment and numerical method.