Research on Quantification Method of Ellipsoidal Defects Based on Leakage Magnetic Detection

Pipeline leakage magnetic detection technology is an effective means to ensure the safe operation of pipelines. The key link in leakage detection technology is to determine the specific size of the defects according to the leakage signal. In the actual pipeline detection process, the defect shape is mostly complex and irregular, and the traditional rectangular defects are difficult to accurately characterize. In order to solve this problem, this article uses ellipsoidal defects as the research object to replace the complex defects in pipeline inspection, combines the ellipsoidal coordinate system, constructs the forward mathematical model of ellipsoidal defects through vector synthesis, and carries out mathematical analysis and calculation of the magnetic distribution law of the leakage signals in the pipeline in the three axes (axial, circumferential, and radial). In addition, a defect size inversion algorithm is constructed based on the constructed mathematical model, and systematic experiments are carried out. The results show that the smaller the length and the larger the width of the defects are more sensitive to the change of depth, and in this model, the errors of solving the radial component of the defects is 14.3% on average, and the errors of solving the axial component is 16.6% on average. The solution accuracy is improved compared to the traditional model. Under this orthogonal mathematical model, the distribution characteristics of the elliptical leakage magnetic field obtained are in good agreement with the inverse model, and the model is of practical significance for improving the quality of defect assessment.