Experimental study on failure behavior of triplex SiC composite tubes under high strain rate internal pressurization

Silicon carbide (SiC) ceramics and composites are promising candidates for nuclear fuel cladding owing to their high-temperature strength, irradiation tolerance, and chemical stability. Evaluating cladding mechanical response under rapid transient loading is critical for accident safety assessment. In this study, the deformation and failure behavior of triplex SiC composite claddings were experimentally investigated at strain rates of 0.5–1.0 s^-1 using a weight-impact-driven pressure burst apparatus. Both nominally non-eccentric and ∼10% eccentric specimens were tested. The high strain-rate deformation and failure behavior under extreme internal pressurization conditions were investigated. The claddings exhibited hoop strain-dominated brittle failure with axially distributed cracks and pronounced interlayer delamination. The average failure hoop strain decreased from 0.636% to 0.483% with increasing eccentricity, indicating a clear negative correlation. Microstructural analyses suggest features consistent with shear-dominated fiber failure and stress-state transformation driven by fiber–matrix interactions, which are associated with enhanced fracture resistance and limited crack propagation.