Damage Mechanism and Reusability Assessment of 2D C/SiC T-Joint Structure Under Typical Loading

The C/SiC composite T-joint is a typical hot structure of hypersonic vehicles, yet its behavior and reusability under repeated loading has not been fully understood. This study targets this typical structure by designing representative loading scenarios, integrating experimental tests and numerical simulations to achieve the analysis of structural mechanical response. The findings indicate that failure modes under monotonic loading exhibit pronounced directional dependence: horizontal tensile loading primarily causes dual rivet line rupture of the outer skin, while tensile loading in the perpendicular direction induces competing failure modes involving interfacial delamination and structural fracture. During cyclic loading (reused conditions), the damage accumulation dynamics were revealed: the maximum historical load defines the damage boundary, whereas the accumulation of irreversible strain linearly reflects stiffness degradation. Despite experiencing approximately 17.26% stiffness reduction, the structure’s residual stress release during cyclic loading results in a 10% increase in ultimate strength. These results showed that C/SiC structure can be reused and its damage can be reflected by the maximum strain. This paper lays foundations for structural reuse and health monitoring.