Research On Health Monitoring Method Based On Fan Blades PVDF Sensor

Wind energy is a pollution-free, clean, renewable green energy, it is paid more and more attention of the countries all over the world. Fan power generation is the most extensive developing and using method to wind energy. Blade is the most critical and basic part of the fan’s component. The safe operation of blade is determinant of the fan normal and stable operation. But blade crack and fracture are widespread and serious safety hazard, it is very important to detect the existence of blade crack timely for the safe operation of fan.This paper presents a method to detect whether blade crack exist or not, which is based on PVDF piezoelectric sensor, through detecting the natural frequency of fan blade in healthy state and cracks existing state. PVDF piezoelectric film has the advantages of low acoustic impedance, wide frequency response, good piezoelectric property, and can be widely used in the actual measurement of all kind of vibration. This paper using PVDF piezoelectric film, and according to its piezoelectric property and mechanics theory, designed and made a piezoelectric sensor based on PVDF piezoelectric film. This sensor can be pasted on the fan blades, and it does not change the dynamic balance and fluid performance of the fan blades, and to get the vibration response curve which appear after applied driving vibration force to the fan blades, and then we can get the natural frequency of the fan blades, finally the natural frequency can react whether blade cracks exist or not. At the same time based on the experimental needs, also designed signal conditioning and data acquisition system to assort with PVDF piezoelectric sensor, through USB via connected with computer and used related software to process experimental data and display. Finally, the experimental proved the accuracy and feasibility of designed PVDF piezoelectric sensor on fan blade cracks detection.