Bolt axial stress detection of electromagnetic ultrasonic signal based on Gabor time-frequency filtering
The measurement of axial preload(axial stress of bolt)of high strength bolt is very important in engineering.When electromagnetic ultrasonic is used to detect bolt axial force,the accuracy of ultrasonic echo time of flight measurement is high.The traditional cross-correlation estimation method is prone to error esti-mation of ultrasonic echo transit time estimation due to noise interference,which cannot meet the requirements of axial force measurement accuracy.In this paper,Gabor time-frequency filtering method is proposed to solve the problem that cross-correlation method is not accurate in estimating the transit time of electromagnetic ultrasonic measurement signal.The measurement signals are collected through the measurement experiment of bolt axial force,the measurement signals are transformed by Gabor,filtered in the time-frequency domain,and then the denoised signals are cross-correlated to estimate the transit time of the measured signals,and then the bolt axial force is calculated.The experimental results show that Gabor time-frequency filtering method can effectively filter the noise in electromagnetic ultrasonic signal,improve the stability of cross-correlation estimation,and improve the accuracy of bolt axial force measurement.
Axial stress of boltCross-correlationTime of flightElectromagnetic ultrasonic signalGabor transformation
万方数据
维普
