Abstract: In order to deeply reveal the grinding mechanism of carbon fibre reinforced ceramic matrix composites (C/SiC), for the current macroscopic single-phase finite element method can not intuitively reflect the failure form of the fibre and matrix, chip type and other problems, this paper comprehensively considered the fibre-interface-matrix interaction mechanism through the numerical simulation method, and established a three-dimensional multi-phase finite element model for multiple abrasive grains to scribe the C/SiC composites and simulation analysis on the scribing model was simulated and analysed for the axial spacing of abrasive grains and the scribing depth. Through the corresponding experimental study, the failure form of matrix and fibre, the chip formation process, the surface damage morphology of the intermediate region under different axial spacing of abrasive grains were elucidated, and the variation trend of the scribing force under different axial spacing and scribing depth of multiple abrasive grains was revealed. The results show that the scribing force of the abrasive grains interacts with each other, leaving more damage on the surface after the scribing of abrasive grain Ⅰ, effectively reducing the scribing force of abrasive grain Ⅱ, and this effect manifests itself as different degrees of interference with different axial spacings, indicating that there exists a strong coupling relationship between the abrasive grains, and the interference between the abrasive grains is insignificant when the spacing is 70 μm, which is the critical spacing. The scribing force is greater along the longitudinal fibres than the transverse fibres, which is due to the fact that the shear strength of the interface is greater than the debonding strength of the interface and the axial strength of the fibres is greater than the radial strength.

Key words: C/SiC composites, multiple abrasive grains scratching, finite element simulation, scribing force, material removal