Mechanical properties and damage analysis of C/C–SiC curved beam under four-point bending: Experimental and numerical investigation

Abstract Since advanced aircraft design requires thorough understanding of the mechanical properties and failure mechanism of ceramic matrix composites (CMC) typical structures, curved beams made of 2D woven C/C–SiC composite under four-point bending is investigated through experimental and numerical studies in this paper. Experiment results show that the average curved beam strength (CBS) is 851.07 N mm/mm and the average equivalent ILTS is 19.25 MPa, and the stitch fiber used to prevent layer shifting has significant effects on structural failure. Validated by experimental data, numerical models based on the cohesive zone method and stitch model can predict curved beam strength as well as delamination crack's initiation and propagation. Besides, the failure mechanism of the stitched curved beam is demonstrated, and the effects of stitch distribution, strength as well as density are discussed, which is meaningful to the optimal design of stitched C/C–SiC curved beam.