| Summary: | 碩士 === 國立臺灣大學 === 工程科學及海洋工程學研究所 === 106 === In this research, we present a pneumatic valve based on bimorph piezoelectric material. The converse effect of piezoelectric materials is used to precisely control the flow rate and pressure in the output port. The bimorph structure was designed to be a one-dimensional plate to reduce the overall size of the piezoelectric actuator. The piezoelectric laminate was slightly compressed to create a pre-stressed condition against the input pressure. The pressure released as the electrical signal is applied to PZT and activated bending deformation. The performances of this system were studied and evaluated, including frequency response, pressure drop, and flow rate.
The piezoelectric actuator was fabricated by attaching two 5 mm wide, 45 mm, 50 mm, or 55 mm long and 0.2 mm thick PZT laminate. With 0.1mm thick stainless steel plate in the middle to form a stainless steel bimorph. With different percentage of the surface electrode (50%, 75%, 100%) design. Two PZT layers are able to create different deformation. The level of the movement was studied under a different driving voltage and operating frequency. Experimental results showed that in the design of 55 mm length 100% electrode and a 0.1 mm shim in the middle can create almost ten times pressure difference with 1Hz square wave 320Vpp driving condition. The optopiezoelectric composite was also introduced to develop an optical controllable valve, and a 63% controllability was achieved.
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