Helicopter Rotor Front Edge Defect Detection Method And Development Of Imaging System

As one of the cores of the helicopter,the rotor will sustain complex alternating cycle stress during operation.Due to its light weight,long life,heat insulation and moisture resistance,rotors using the new composite metal hybrid structure have advantages that traditional metal rotors do not possess.Due to the special manufacturing process of the rotor rotor leading edge,the iron-glass fiber composite layer on the leading edge is prone to debonding defects,so it is necessary to detect the defects of the composite layer.For the in-situ detection requirements of the rotor of this type of helicopter,the complex layer structure is complex and the defect exists inside.The conventional detection method cannot detect it.In this study,an ultrasonic feature scanning and inspection system was developed to perform imaging detection on the rotor front simulation test block and the actual sample to achieve complete detection of the composite layer.The main work is as follows:First,the geometry of the leading edge of the rotor is analyzed,and a single probe reflection method is used to detect the composite layer.The acoustic characteristics of the leading edge of the rotor are measured and analyzed,and the principle of the single probe reflection defect recognition is explained by using the influence of acoustic impedance difference on the reflection and transmission coefficient of the composite layer.Secondly,according to the external field of the rotor leading edge,imaging,in-situ detection requirements and the thin-walled curved surface structure of the leading edge of the rotor,a portable ultrasonic imaging scanning imaging detection system was developed.The two-axis belt module and the probe holding device are used to complete the coupling,and the plexiglass block is used to complete the probe waveform focusing and interface wave back-shifting.Finally,an artificial defect simulation test block was made and a calibration test was performed to obtain the best detection ultrasonic parameters.Then use the portable ultrasonic scanning imaging detection system to detect the helicopter rotor prototype and analyze the defect location and accuracy.The results show that the ultrasonic imaging method can identify the debonding defects of the iron-glass fiber composite layer on the leading edge of the helicopter rotor.The portable ultrasonic feature scanning imaging system was used to test the simulated test block and the actual sample.The test results show that the system can meet the requirements of the helicopter rotor's leading edge in-situ detection,and can achieve precise positioning and quantification of detackification defects with an accuracy of 1mm.The system makes up for the gap in the precise positioning and quantitative defect detection of the helicopter rotor wing leading edge.