Quantitative Analysis Of Wind Turbine Blade Defects Based On Ultrasonic Detection

Wind turbine blades are the key components for stable operation of wind turbines under harsh conditions.Due to factors such as the complex blade production process and the harsh environment,wind turbine blades are prone to defects of various types and sizes.Therefore,in order to ensure the normal operation of wind turbines,it is very necessary to detect defects on the blades.This paper analyzes the relationship between the acoustic parameters in the ultrasonic signal and the size of the defect,and proposes to use the kurtosis index characteristic curve to determine the size of the defect.This method reduces the dependence on manual experience in the traditional ultrasonic inspection quantification,improves the quantification accuracy,and greatly simplifies Traditional characterization curve.The research content and results of this article are as follows:(1)Through the COMSOL finite element simulation software,the FRP laminated composite model was established,and five inclusion defects with depths of 16 sizes were set inside it.Through the displacement cloud diagram and the extracted waveform diagram,it was found that at the same depth,with the size of the defect With the increase of,the reflected echo energy increases,and the defect echo amplitude increases.Under the same size,as the depth of the defect increases,the attenuation of the defect echo reflected energy increases.(2)The amplitude acoustic parameters of the flaw ultrasonic signal in the simulation are extracted,the depth-amplitude-size diagram is established,and the correlation between the flaw echo and the initial wave spectrogram is analyzed.Using EMD adaptive decomposition,considering the influence of frequency on time-domain volatility,the acoustic parameter-kurtosis index is defined,and the kurtosis index of defects of the same size at different depths is found,which is well aggregated on the characteristic curve of kurtosis index.(3)The inclusion of steel defects in the glass fiber composite material was produced.The experiment found that the actual signal amplitude variation law obtained is consistent with the simulation result.The signal was detected by the ultrasonic experiment with 3 defects at a depth of 18 mm,and the kurtosis index fitting curve was obtained.The curve was used to size the defects in the experiment with a depth of 21 mm.Quantitative,it is found that the quantitative error is small,and the overall average error of the entire quantification is 2.88%.The simplification of the traditional quantitative curve and the improvement of accuracy are realized,which is of great significance for the characterization of the size of defects in wind power materials.