A time-dependent vibration damping model of fiber-reinforced ceramic-matrix composites at elevated temperature

In this paper, a time-dependent vibration damping model of fiber-reinforced ceramic-matrix composites (CMCs) is developed. Considering time and temperature dependent interface damages of oxidation, debonding, and slip, the relationships between composite vibration damping, material properties, internal damages, oxidation duration and temperature are established. The effects of material properties, vibration stress, damage state, and oxidation temperature on time-dependent composite vibration damping and interface damages of C/SiC composite are discussed. The time-dependent composite vibration damping decreases with fiber volume, matrix crack spacing and interface shear stress, and increases with vibration stress. The experimental composite vibration damping and internal damages of 2D C/SiC composite for different oxidation duration t = 2, 5 and 10 h at elevated temperatures T = 700, 1000 and 1300 degrees C are predicted. When the oxidation duration was short (i.e., t = 2 h), the composite vibration damping decreased with temperature; however, when the oxidation duration was long (i.e., t = 5 and 10 h), the composite vibration damping decreased with temperature below 1000 degrees C, and increased with temperature to 1300 degrees C.