Stochastic Simulation of Thermal Residual Stress in Environmental Barrier Coated 2.5D Woven Ceramic Matrix Composites

This paper deals with the evolution of thermal residual stress (TRS) in Ceramic Matrix Composites (CMC) with environmental barrier coating (EBC) for aeroengine applications. In particular, in hot section component applications, where the durability requirement is of primary concern, CMC/EBC materials seem to be the most fascinating solution for effective and performant design. In this work, a numerical analysis has been conducted to study the effect of TRS on the damage mechanism in the 2.5D woven CMC coated with EBC. To figure out the heterogeneous and stochastic evolution of TRS in the coatings and substrate, a micromechanical finite element model of the composites containing the coatings was established based on the concept of representative volume elements. Especially, the variation of microstructure characteristics and constituents properties were taken into account in the micromechanical model. A series of simulations were performed to investigate the evolution of TRS during the cooling process after preparation and the thermo-mechanical loading process. Then, the thermal stress in coatings and substrate was calculated, and the influence mechanism of TRS on the failure was analyzed by comparison. The driven mechanism of the delamination crack and vertical crack was discussed based on the TRS results with uncertain characteristics. Based on this, uncertainty quantification can be performed to predict the durability life of the CMC/EBC system.