Measuring Elastic Constants of Piezoelectric Material and Flowing Fluid Viscosity by Ultrasonic Testing Method
Date Issued
2005
Date
2005
Author(s)
Chen, Yi-Lin
DOI
zh-TW
Abstract
Ultrasonic inspection, a technique of non-destructive test (NDT), is widely applied in material properties testing because of its low cost and high accuracy. Elastic constants of materials play an important role in many engineering applications and designs. In general, the piezoelectric material properties are not easily obtained from tensile test. Therefore, the non-destructive ultrasonic technique is used in this study to evaluate phase velocities by pulse-echo and amplitude-spectrum methods, and then determine the elastic constants of materials by using phase velocities. In this regard, the experimental results of phase velocities did an excellent work in correlating the standard values calculated from the wave propagation theory.
The influence of buffer layer on the experimental measurement for the thin layer system has also been investigated in this study. We replaced solid buffer layer with liquid ones which has different viscosity and layer thickness to analyze the differences of longitudinal wave velocity between different test conditions. The accuracy of experimental measurement on longitudinal wave velocity will be increased with the increasing liquid viscosity.
In addition, the viscosity of thin liquid layer in static equilibrium and the environmental influence on the liquid viscosity are also discussed. The viscosity of liquids are obtained by inverting the wave velocities and attenuation coefficients with amplitude-spectrum method. The viscosities of liquid obtained in this study agree with the results presented in the literature. Furthermore, the viscosity of flowing fluid is measured by a self-designed liquid circular system.
Subjects
超音波檢測
壓電材料彈性常數
振幅頻譜法
液體黏度
Ultrasonic inspection
Elastic constants
amplitude-spectrum method
viscosity
Type
thesis
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