A micromechanical temperature-dependent vibration damping model of fiber-reinforced ceramic-matrix composites

Abstract

In this paper, a micromechanical temperature-dependent vibration damping model of fiber-reinforced ceramic-matrix composites (CMCs) is developed. Temperature-dependent damage mechanisms of matrix cracking, interface debonding and slip, and fibers fracture contribute to the vibration damping of damaged CMCs. The temperature-dependent fiber and matrix strain energy and dissipated energy density are formulated of composite constituent properties and damage related micro parameters of matrix crack spacing, interface debonding and slip length, and broken fibers fraction. Theoretical relationships between temperature-dependent composite damping, temperature and temperature-dependent damage mechanisms are established. Effects of composite constituent properties (i.e., fiber volume, interface debonding energy, interface shear stress and interface frictional coefficient) and composite damage state (i.e., matrix crack spacing) on temperature-dependent composite vibration damping of SiC/SiC composite are analyzed. When the fiber volume increases, the composite vibration damping decreases, and the temperature for the peak value of the composite vibration damping increases, mainly due to the decrease of the interface debonding and slip fraction. Experimental temperature-dependent composite vibration damping of 2D SiC/SiC composite at the temperature range of 293–1373 K are predicted using the developed micromechanical vibration damping model. Experimental vibration damping of 2D SiC/SiC composite increases with temperature, and the theoretical predicted composite vibration damping for different vibration stress of σ = 5, 6, and 7 MPa are obtained and agreed with experimental data, and the predicted interface debonding and slip fraction increases with temperature.