Ceramics-Silikáty 64, (4) 387 - 397 (2020)

In this paper, the synergistic effects of fibre debonding and fracturing on vibration damping in fibre-reinforced ceramic-matrix composites (CMCs) is investigated. The relationships between the damping of the CMCs, the damping of the fibre and the matrix, the damping caused by the frictional slip between the fibre and the matrix, and the fibre debonding and fracturing are established. The effects of the fibre volume, matrix crack spacing, interface shear stress, interface debonding energy, fibre strength and fibre Weibull modulus on the damping of the CMCs, the interface debonding and slip between the fibre and the matrix, and the fibre broken fraction are analysed. The damping of the unidirectional CMCs with and without considering the fibre failure is discussed. The experimental damping of a 2D C/SiC composite is predicted using the present analysis. When the fibre volume increases, the composite damping decreases, due to the decrease in the interface debonding and slip length and the broken fibre fraction. Considering the fibre failure, the composite damping decreases, due to the increase in the fibre broken fraction. When the fibre strength and fibre Weibull modulus increase, the composite damping increases, due to the decrease of the interface debonding length, interface slip length, and broken fibre fraction.