Development Of Ultrasonic Flaw Detection Instrument For Fan Tower Bolts

Each level of the wind turbine tower is connected by bolts,if the bolts break and fail,it is easy to cause unnecessary economic or safety accidents,so it is necessary to maintain and test the tower bolts regularly.As a technical means of nondestructive testing,ultrasonic testing has become the most commonly used technical means in engineering testing because of its strong penetration and reliable detection.Based on the requirement of regular inspection of tower bolts in wind farms,this paper designs and develops an ultrasonic flaw detection instrument for tower bolts of wind turbines.The main work completed is as follows:(1)Studied the development status of ultrasonic nondestructive testing technology,introduced the theory and principle of ultrasonic nondestructive testing,analyzed the key points in the process of ultrasonic testing and the factors affecting the results,and based on the principle of ultrasonic flaw detection,designed the hardware and software system of ultrasonic flaw detection instrument for wind turbine tower bolts.(2)Aiming at the defects of the connecting bolts of the wind turbine tower,based on the direct probe pulse reflection method,the hardware circuit with STM32 chip as the core is designed,including ultrasonic emission circuit,gain amplification circuit,filter circuit,detection circuit and analog-to-digital conversion acquisition circuit,and the program is written to complete the design of the hardware scheme.(3)In order to realize the accurate judgment of the acquired echo signal,based on VB,designed upper computer software program to realize the display and analysis of the collected data,and the software processing module is designed based on the Hilbert transform and the Fourier transform respectively,realized the envelope and spectrum analysis of echo signal.(4)The circuit of the ultrasonic flaw detection instrument was tested after the design,and the standard test block and the connecting detection bolt of the fan tower were respectively taken as the object of the experiment,which verified the accuracy of the defect detection of the tower connection bolt,and achieved the research purpose.