Multi-scale analysis of SiC_f/SiC composite dovetail considering realistic porosity facilitated by X-ray computed tomography

In this study, a multi-scale analysing strategy has been proposed to elucidate the effect of different scales of pores on the tensile performance of ceramic matrix composite (CMC) dovetails. The morphological characteristics and spatial distribution of pores in the CMC dovetails have been revealed in three dimensions by X-ray computed tomography. A multi-scale approach, taking into account the observed actual characteristics of different scales of pores, has been established to generate CMC dovetail models containing (1) both macro- and micro-pores, (2) macro-pores only and (3) no pores. The experimental and simulation results show good consistency when pores are accommodated (the error in peak load is 4.01%), highlighting the importance of considering pores when predicting the mechanical properties of CMC dovetails. It has been found that macro-pores play a vital role in degrading the stiffness and strength of the CMC dovetail structure. In terms of damage accumulation behaviour, the presence of micro-pores accelerates damage initiation in the form of matrix cracking, while macro-pores control the final fracture morphology of the dovetail structure.