Research On Defect Detection Of Wind Turbine Blade Based On Infrared Thermal Imaging Technology

With global warming,increasing environmental pollution and increasing consumption of fossil energy,wind energy,as a clean and renewable energy source,has gradually received attention from all countries.At present,the wind power market is growing rapidly.The defect detection of wind turbine blades(hereinafter referred to as wind blades)has attracted the attention of engineers and scientific researchers,which directly affects the safe operation and economic benefits of wind farms.In this thesis,the method of combining finite element simulation and experiment is used to study the non-destructive detection technology of infrared thermal imaging defects of fan blades.The main contents are as follows:1)Above all,the theoretical basis and detection principle of infrared thermal imaging non-destructive testing are introduced,combined with the fan blade itself and actual working parameters,the calculation of the fan blade radiation spectrum wavelength range is calculated,and the detection method and excitation of the subsequent fan blade infrared thermal imaging non-destructive testing experiment are determined.Source,proposed methods to reduce the influence of unfavorable factors,and laid the foundation for the simulation and experiment in the following.2)Using ANSYS finite element software to simulate the heating-natural cooling process of wind blades.Through direct thermal analysis and transient thermal analysis,comparing and studying the temperature field cloud diagram and temperature-time curve diagram,and summarizing the defect area and non-defect area.Heat transfer differences and characteristics,and further explored the influence of different excitation conditions on the effect of defect detection,providing empirical parameters for the actual defect detection of wind blades.3)According to the design and processing of the wind blade specimens,the builtin indoor infrared thermal imaging defect non-destructive testing experimental system,the use of flashing lights for manual controllable excitation thermal imaging experiments,the acquired thermal image sequence,using fast Fourier transform(fast Fourier transform,FFT),principal component analysis(principal component analysis,PCA),FFT to eliminate DC component and PCA to eliminate DC component for defect feature extraction,to achieve better defect detection results.At the same time,the influence of different radiation intensities,different heating cycles and different heating processes on the defect detection effect is analyzed,which has guiding significance for the realization of subsequent natural uncontrollable thermal imaging experiments.4)The natural uncontrollable thermal imaging experiment was performed on the telescope using sunlight,and the defects of the glass fiber flat specimen and the wind blade specimen were successfully detected,verifying the feasibility and effectiveness of using the natural thermal excitation of sunlight to perform non-destructive detection of wind blade defects.Provides a solution idea for the online defect non-destructive testing of the blades of the in-service wind.