Research On Technology Of Piezoelectric Intelligent Material In Flow Velocity And Pressure Real-time Monitoring

PVDF(Polyvinylidene Fluoride) piezoelectric films are one of most important smart materials, and using it to design sensors is the new focus of research of smart/intelligent materials and structures in recent years. In the thesis, the sensing principle of PVDF pressure sensor was studied, by using PVDF piezoelectric film as sensing element in flow monitoring system, the relationship between the flow and the voltage of the plates on PVDF pressure sensor was established, and then the real-time flow monitoring system was set up. With the assumption that the flow changes according to the random curve, the change of the flow, the voltage and the flow pressure with time were analyzed with MATLAB, which carried on beneficial exploration to the smart material or structure.The main areas covered by the thesis are:1. The sensing mechanism of PVDF pressure sensor was introduced basing on the study of piezoelectric effect of PVDF piezoelectric film.2. The flow pressure the relationship between the flow and the voltage of the plates on PVDF pressure sensor was presented, the equivalent circuit and the measuring circuit of PVDF pressure sensor was studied, and also the sensitivity was discussed.3. With the underwater structures as carrier, the method of that PVDF piezoelectric intelligent structure is used for measure of flow velocity and flow pressure is discussed.4. the example was presented to explain the design mind and demonstrate the effectiveness of the method, with MATLAB using the variation of random signal of flow velocity along time as example, the relationship curve of voltage signal and flow pressure along time were fitted, and the relationship between flow velocity and voltage signal in the flow velocity monitoring system based on PVDF piezoelectric film pressure sensors was analyzed.