Thermal expansion coefficients of unidirectional fiber-reinforced ceramics
The influence of internal stresses, due to the thermomechanical mismatch between the fiber and the matrix, on the thermal expansion behavior of unidirectional fiber reinforced ceramics is considered. Using the composite cylinder model, the effective thermal expansion coefficients of the composite are calculated from the total strains, which consist of the strains due to temperature changes and the strains induced by the presence of internal stresses. The results reveal that when the fiber and the matrix have the same elastic constants, the rule of mixtures approach can be used to obtain the thermal expansion coefficients of the composite, as observed in previous analytical solutions. Also, for the case of low volume fractions of fibers with Young's moduli much larger than those of matrices, and the thermal expansion coefficients lower than those of matrices, the transverse thermal expansion coefficient of the composite is higher than that of either the fiber or the matrix. However, unlike previous studies, the present analysis provides a physical basis for this phenomenon in terms of the internal thermal stress state within the composite.
- Research Organization:
- Metals and Ceramics Div., Oak Ridge National Lab., Oak Ridge, TN (US)
- OSTI ID:
- 6265305
- Journal Information:
- J. Am. Ceram. Soc.; (United States), Vol. 71:10
- Country of Publication:
- United States
- Language:
- English
Similar Records
Investigation of failure modes in fiber-reinforced ceramic-matrix composites. Master's thesis
The relationship between longitudinal stress and transverse strain during tensile testing of unidirectional fiber toughened ceramic matrix composites