Cohesive Zone Finite Element Modeling of Delamination Initiation and Propagation in Ceramic Matrix Composites

Delaminations may initiate and propagate in two-dimensional ceramic matrix composites (CMC) when they are subjected to multiaxial stress states. Such stress states may arise as a result of the applied loading and/or due to complex features within the CMC components such as matrix-rich regions, ply curvature, and notches. An effective way to model delaminations is to use a cohesive zone methodology. In this methodology potential interfaces where delaminations may occur are modeled explicitly using either cohesive finite elements or contact-based cohesive surfaces. The initiation and propagation of delamination is controlled by the traction-separation constitutive response of the cohesive zone that characterizes the interface fracture behavior.

In this work the cohesive zone approach is used to study the initiation and propagation of delamination in various test coupons and sub-elements made from a 2D woven CMC. The results from the finite element simulations are compared with the experimental results where available. A parametric study is conducted to understand the effect of variation in cohesive material properties on the delamination initiation and growth and the overall response of the sub-elements.