Fatigue Crack Growth Behavior of a Woven HPZ/Silicon Carbide Ceramic Matrix Composite

This paper discusses the results of an investigation of the fatigue crack growth behavior of a silicon-nitrogen-carbon-oxygen/silicon carbide (HPZ/SiC) ceramic matrix composite containing an 8 harness satin weave fiber architecture. Crack growth during the tests was monitored using optical and scanning electron microscopy as well as specimen compliance. The fatigue crack growth behavior of the composite and the monolithic matrix was used to characterize the fiber bridging mechanism during fatigue loading. A shear lag crack bridging model was used to deduce the fiber/matrix interfacial shear stress during the crack propagation. The effect of fatigue loading on the predicted fiber bridging stresses and crack opening displacements are also discussed.