| Summary: | 碩士 === 國立中興大學 === 機械工程學系所 === 103 === The paper goes on our laboratory’s the bridge PZT gauge element. the main use of piezoelectric effect and inverse piezoelectric effect theory. , and the theory of damping vibrations have structural damping effect and gas damping effect. At low gas pressure, the gas damping force low impact. Therefore, when the input voltage PZT material would be more large deformation, and thus make the overall structure of the output of the voltage output upgrade. In this research, the main use of this feature to vacuum pressure measurement. It can be discussed under different pressures, changes and the piezoelectric damping ratio of output change. Also developed a double disc-type PZT piezoelectric gauges, in order to increase the surface area of the gas contacts the specimen, so that the damping effect increases the gas, and observe the measurement results.
After the bridge test pieces and disc-type specimen produced and fixed, the resonance frequency will be computer simulation and experimental measurements for comparison, also using optical displacement meter enter a fixed frequency (the resonant frequency of the test piece) of the voltage and check the specimen deformation compliance with computer simulation. Thereby to determine whether the quality is good, if no problem will gauge element used in vacuum pressure measurement experiments.
Previous research by the mathematical model, it is possible that the damping ratio exhibits an inverse relationship with the Vout/Vin.When the vacuum pressure high, gas damping greater the impact will cause the output decline. From the spectrum analyzer get frequency response diagram can be used to calculate damping ratio, damping ratio calculated on the use of half-power method.Finally, the experimental results measured can explore different vacuum pressures, changes in circumstances damping ratio are consistent with the mathematical model and theory.
Finally, you can learn from the experiment, the researchers designed the bridge in a vacuum gauge and piezoelectric disc piezoelectric gauge can be measured to 760 ~ 6.5E-6Torr the vacuum range,bridge specimen after change package, can find the volume previously piezoelectric gauge bridge device volume reduction of about 1/3, and the ratio of change in output is also more sensitive. and make disc-type PZT vacuum gauge, in order to increase the contact area of the specimen gases, and finally with the measurement results compared vacuum gauge bridge and explore its advantages and disadvantages.
Keywords: PZT piezoelectric sensors, vacuum gauge, damping ratio
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