ANALYTICAL AND NUMERICAL SHEAR-LAG MODELS DESCRIBING PROBABILISTIC RUPTURES IN CERAMIC MATRIX MINI-COMPOSITES

Due to their excellent thermomechanical properties, ceramic matrix composites (CMC) are being assessed for high temperature applications in the aerospace and nuclear industries. Despite their brittle elastic behaviour, the addition of a weak interphase can induce a pseudo-ductile macroscopic behaviour by deflecting matrix cracks at the fibre/matrix interface. The shear lag model is conventionally used to describe this behaviour. This model describes the evolution of stresses in the matrix and fibres around a crack. The prediction of new matrix cracks is therefore crucial in determining the overall mechanical behaviour of the composite. Several models can describe the evolution of matrix cracking. In particular, the Weibull law associated with a Poisson Point Process (PPP) can be used. Several test cases were carried out and analysed to compare their implementation (numerical or analytical) and understand the influence of some assumptions, such as periodicity, on the modelling of unidirectional composites.