In order to implement ceramic matrix composite (CMC) materials into components for aero engines, their mechanical performance under various loading conditions, such as ultimate strength, fracture resistance, and fatigue tolerance, must be well understood. One of the areas of concern is the delamination failure of CMCs materials under Mode I, Mode II and Mixed Mode loading conditions. This type of failure is unusual in metallic alloys, but common in composite materials since they are manufactured through assemblies of layers / plies and separation between the layers under mechanical and thermal loading is prone to occur. The mechanical response of CMCs under unidirectional on- and off-axis monotonic and cyclic loading has been extensively studied, however, limited work has been performed on other types of damage, specifically interlaminar properties

Interlaminar fracture properties play a vital role in CMCs, especially when being considered for application in aero engine due  in part to their exposure to large thermal gradients, which induce interlaminar normal or shear stresses. The weakest plane for CMCs is the interlaminar plane where the majority of fibres are aligned in one of the orthogonal axial directions. The complex architecture of woven CMCs and any internal porosity or voids in the material due to processing can introduce regions of stress concentration which are then prone to the development of interlaminar cracks depending upon the loading condition.

This work compares the development and results of three types of Interlaminar tension tests; button testing, flatwise Interlaminar tension tests in a 4 point bend configuration and diametrical disc compression testing, the latter of which has also been conducted at high temperatures (>1000°C). Using techniques such as digital image correlation and predictive analysis such as Weibull distributions, the strain development and characteristic failure strengths of the stochastic material has been determined.