Ultrasonic characterization of fiber-matrix interphasial properties and damage in high-temperature composites. Ph.D. Thesis
This study addresses ultrasonic characterization of fiber-matrix interphasial properties and damage in high-temperature composites. To accomplish this, experimental techniques for measurements of ultrasonic phase velocities and methodology for calculation of composite elastic moduli from velocity data are first developed and applied to unidirectional ceramic and intermetallic matrix composites. It is shown that computational error in the composite moduli is comparable to experimental error in the velocity data. For cross-ply composites, a novel method for determination of lamina elastic moduli from measurements on a (0/90)(8) composite is developed and validated experimentally. Second, a method to determine the elastic moduli of interphasial layers in high-temperature composites from the measured composite moduli is developed and applied to characterization of 3-micron thick carbon interphasial layers in ceramic and intermetallic matrix composites. Third, the techniques developed are used for assessment of oxidation and fatigue damage in ceramic and metal matrix composites. It is shown that ultrasonic phase velocities are very sensitive to damage and can effectively quantify damage severity. Appropriate models are applied to describe the effect of damage on the measured ultrasonic data, and they show reasonable agreement with experiments.
- Research Organization:
- Ohio State Univ., Columbus, OH (United States)
- OSTI ID:
- 102030
- Country of Publication:
- United States
- Language:
- English
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