Effect of interlaminar defects on the mechanical behaviour of carbon fibre reinforced silicon carbide

Abstract

Ceramic‐Matrix Composites (CMCs) are high‐potential materials for light‐weight structures in high temperature applications. CMCs show high temperature resistance like monolithic ceramics. But in contrast to monolithic ceramics CMCs do also show a high damage tolerance which makes the design of large light‐weight CMC‐structures possible. One limiting factor for CMCs in industrial application is the precise design of CMC components. Due to the complex, high temperature manufacturing of CMC components it is not always possible to prevent the formation of processing defects completely. Therefore, manufacturing defects are leading to high rejection rates, costs and to an oversizing of CMC components. In this way the full light‐weight potential is not tapped and new fields of application are lost. With the help of modern non‐destructive testing methods, like micro‐Computer Tomography (CT), most of the macroscopic defects can be detected with high resolution and detection reliability. Nevertheless, the impact of defects on stiffness and strength of CMC materials and structures is still not clear. Thus the effect of interlaminar defects is approached by integrating the defect information from micro‐CT into Finite Element (FE) models. With the help of the adequate material and fracture mechanical models, it should be possible to predict the stiffness and strength of samples and structures with manufacturing defects. The ability to assess the impact of defects on the performance of CMC structures can help to minimize rejection rates and accelerate material and process optimization by focusing on design critical defects only.