Magnetic Flux Leakage Detection Defect of Oil Storage Tank Applying Variational Mode Decomposition

摘要

Corrosion, stress and mechanical damage of oil storage tank can lead to disastrous consequences. Therefore, it is very important to study a reasonable and effective method for detecting tank defect. Signal processing and defect recognition technique is one of the most important techniques in oil tank inspection magnetic flux leakage system, the paper discussed its signal processing procedure. First the noise robustness of the variational modal decomposition (VMD) is analyzed, and compared with wavelet decomposition and empirical mode decomposition (EMD) respectively to verify the superiority of VMD in signal-to-noise ratio. Especially in the low-band signal decomposition processing VMD has obvious advantages. Detection is then discussed the application of the magnetic flux leakage method in the tank defects, and verified the feasibility by the magnetic flux leakage detection in a laboratory platform. Finally, the VMD algorithm is used to decompose and reconstruct the magnetic flux leakage signal of the oil storage tank wall, and the leakage magnetic signal is effectively decomposed to achieve the de-noising effect and the modal function of the required frequency band is extracted to achieve the purpose of denoising. The validity of the proposed method is proved by means of the magnetic flux leakage detection technique based on VMD.