Modeling Of Resonant Piezoelectric Ice Sensor

Ice is a phenomenon of nature. Icing under control benefits more than individually and economically. However, as a weather disaster, ice causes impairments in fields of agriculture, industry, transportation and so on. In order to minimize the damages of ice, it is of great importance to detect whether there is icing on surface of the interested objects, as well as to measure the ice thickness in time. Therefore, a resonant piezoelectric ice sensor has been studied and developed.In this thesis piezoelectric behavior of piezoelectric ceramics is briefly described. The diaphragm ice sensor is designed based on the piezoelectricity effect and counter piezoelectricity effect, as well as mechanical resonance theory. Accretion of ice on the sensor surface changes the effective mass and stiffness of the vibrating sensing element. These variations are obtained by measuring the changes in sensor resonant frequency. Also, the theoretical study and the model of the diaphragm ice sensor are presented. The diaphragm is studied using an approximate analytical method and the resonance frequency equations are obtained. And the certain corresponding relation between ice thickness and resonance frequency of the sensor is determined.Repeatability experiments are also conducted to investigate the frequency characteristic at room temperature, the variation of flat diaphragm resonant frequency due to different ice film thickness at -20℃. The results of the experiments are analyzed to demonstrate the relations between ice thickness and resonance frequency of the sensor.Based on comparisons of the theoretical results and the experimental data, the relation between the resonance frequency of the sensor and the variations of the physical parameters of the composite diaphragm are obtained.