Nonlinear Resonance Ultrasound Spectroscopy for Carbon Carbon Samples
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Bhat, Keshav R.
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Abstract
Carbon-Carbon (C-C) composites are becoming increasingly popular in aerospace applications. X-Ray Computed Tomography (XCT) is the preferred technique for nondestructively testing for micro-damage in these materials. However, it is a time consuming and expensive method. Ultrasonic techniques offer a cheaper and more flexible option for testing these materials.
The aim of this research is to use the nonlinear resonant ultrasound spectroscopy (NRUS) technique to determine the influence of microscopic material damage in C-C composites on the hysteretic nonlinearity parameter α. This study applies contact and non-contact setups of the NRUS technique to C-C specimens in the pristine and damaged state.
Multiple longitudinal and flexural modes of vibration are excited, and the nonlinearity trends are studied for each mode for increasing levels of micro-damage. The positive correlation between the hysteretic nonlinearity parameter to micro-damage from cyclic 3-point bending is established. The efficacy of using NRUS to determine damage induced by high-temperature thermal oxidation is determined and the trend compared that of the linear resonant frequency.
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Date
2024-01-16
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