Three-dimensional magnetic flux leakage testing defect contour reconstruction method and device

Abstract

The invention discloses a three-dimensional magnetic flux leakage testing defect contour reconstruction method and a device. The three-dimensional magnetic flux leakage testing defect contour reconstruction method comprises following steps: a forward finite element calculation model is constructed; characteristic constants of a defect magnetic flux leakage field are extracted; initial estimate values of defect contour parameters are obtained based on the characteristic constants, and the initial estimate values are introduced into the forward finite element calculation model as input values for iterative computations so as to obtain leakage magnetic field predicted values, wherein the defect contour parameters are updated via heuristic optimization algorithm so as to obtain defect contour parameter expectancy values and realize defect reconstruction. The three-dimensional magnetic flux leakage testing defect contour reconstruction method is capable of increasing defect reconstruction efficiency; stability is high; calculation is accurate; and speed is high; so that it is beneficial for increasing of reconstruction speed and precision of irregular defects.

Description

technical field [0001] The invention relates to the technical field of nondestructive testing, in particular to a method and device for reconstructing defect contours in three-dimensional magnetic flux leakage testing. Background technique [0002] Due to the advantages of simple principle, strong online detection ability and good detection effect, magnetic flux leakage detection is widely used in the field of quality detection and safety monitoring of ferromagnetic materials such as oil and gas pipelines, storage tank bottom plates, and steel wire ropes. However, due to the uncertainty of the defect shape and the complex nonlinear relationship between the magnetic flux leakage signal and the defect shape, the reconstruction of the defect contour has become a difficult point and a hot spot in the current research of magnetic flux leakage detection technology. Most of the existing defect reconstruction methods use the single-axis magnetic flux leakage detection signal as the ...

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Problems solved by technology

However, due to the uncertainty of the defect shape and the complex nonlinear relationship between the magnetic flux leakage signal and the defect shape, the reconstruction of the defect contour has become a difficult point and a hot spot in the current research of magnetic flux leakage detection technology.

Most of the existing defect reconstruction methods use the single-axis magnetic flux leakage detection signal as the data source to perform two-dimensional reconstruction or indirectly achieve three-dimensional reconstruction through interpolation on the two-dimensional basis. These reconstruction methods have a single detection signal source and complex calculation models , the amount of calculation is large, and the reconstruction accuracy is low

[0003] In the related technology, for example, a two-dimensional reconstruction method of oil pipeline defect least squares support vector machine, although the denoised and normalized pipeline magnetic flux leakage signal data can be used to reconstruct the pipeline defect contour, but It is limited to two-dimensional reconstruction, that is, inversion of a certain fault profile of the defect, and the accuracy is difficult to guarantee; for example, the MFL defect reconstruction method based on cuckoo search and particle filter hybrid algorithm, although it can be accurately realized to a certain extent Defect contour reconstruction, in particular, can reduce signal noise and improve the robustness of the iterative method to noise, but it is still a two-dimensional reconstruction of defect contour, and the calculation model is too complicated, the calculation amount is large, and the efficiency is not high

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