Unit combination defect magnetic flux leakage signal calculating method along magnetization direction

A technology of magnetization direction and calculation method, applied in the direction of the magnitude/direction of the magnetic field, material magnetic variables, complex mathematical operations, etc., can solve problems such as representation, and achieve the effect of simple calculation model, improved calculation efficiency, and fast speed

Active Publication Date: 2017-07-04
TSINGHUA UNIV
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  • Abstract
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  • Application Information

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Problems solved by technology

However, there is a serious nonlinear relationship between the target defect size and its magnetic flux leakage signal, so it is impossible to use the pre-calculated known defect magnetic flux leakage signal or its combination to directly represent the target defect magnetic flux leakage signal
Currently there is no method to calculate the MFL signal of the target defect based on the pre-calculated MFL signal of known defects

Method used

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  • Unit combination defect magnetic flux leakage signal calculating method along magnetization direction
  • Unit combination defect magnetic flux leakage signal calculating method along magnetization direction
  • Unit combination defect magnetic flux leakage signal calculating method along magnetization direction

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Embodiment 1

[0056] In this embodiment, the method for calculating the magnetic flux leakage signal of unit combination defects along the magnetization direction includes the following steps:

[0057] 1. Select the unit defect size according to the target defect size. Specifically include: the length of the target defect l=24mm, the width w=12mm and the depth d=3.6mm, the target defect is a combination of unit defects along the magnetization direction; the size of the selected unit defect is: length l 0 =l / 2=12mm, width w 0 =w=12mm and depth d 0 =d=3.6 mm. Among them, l 0 and l is the length of the defect, along the magnetization direction; w 0 and w is the width of the defect, perpendicular to the magnetization direction; d 0 and d is the depth of the defect, along the thickness of the material being tested.

[0058] 2. Obtain the unit defect magnetic flux leakage signal H E (x, y, z), where the unit defect flux leakage signal H E (x,y,z) is based on the unit defect size l 0 =12m...

Embodiment 2

[0072] In this embodiment, the method for calculating the magnetic flux leakage signal of unit combination defects along the magnetization direction includes the following steps:

[0073] Step 1: Select the unit defect size according to the target defect size. Specifically include: the length l=48mm of the target defect, the width w=24mm and the depth d=4.8mm, the target defect is a combination of unit defects along the magnetization direction; the selected unit defect size is: length l 0 =l / 2=24mm, width w 0 =w=24mm and depth d 0 =d=4.8mm. Among them, l 0 and l is the length of the defect, along the magnetization direction; w 0 and w is the width of the defect, perpendicular to the magnetization direction; d 0 and d is the depth of the defect, along the thickness of the material being tested.

[0074] Step 2: Obtain the unit defect magnetic flux leakage signal H E (x, y, z), where the unit defect flux leakage signal H E (x,y,z) is based on the unit defect size l 0 =2...

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Abstract

The invention relates to a unit combination defect magnetic flux leakage signal calculating method along magnetization direction. The method comprises the following steps: S1) selecting the unit defect size according to the preset target defect size; S2) obtaining a unit defect magnetic flux leakage signal; S3) performing three-dimensional Fourier transform on the unit defect magnetic flux leakage signal to obtain a frequency domain signal after transformation; S4) performing translation transformation operation on the frequency domain signal after transformation along the magnetization direction to obtain two frequency domain signals after translation transformation; S5) performing combination operation on two frequency domain signals after translation transformation along the magnetization direction to obtain the frequency domain signal after combination; and S6) performing three dimensional fourier inversion on the frequency domain signal after combination to obtain the magnetic flux leakage signal of the target defect. According to the invention, complex calculating such as finite element is not required for the target defect for second time, and the method has the advantages of simple calculating model and fast speed.

Description

technical field [0001] The invention relates to the technical field of nondestructive testing, in particular to a method for calculating magnetic flux leakage signals of unit combination defects along the magnetization direction. Background technique [0002] The calculation of defect magnetic flux leakage signal is the basis of magnetic flux leakage detection and defect evaluation. Due to the incomplete mapping of the defect magnetic flux leakage signal to the defect size, it is usually necessary to construct a forward model to solve the magnetic flux leakage signal based on the known defect size, and iteratively update the defect size parameters in the model to approach the target magnetic flux leakage signal, so as to realize the defect Inversion of size. Therefore, how to quickly and accurately calculate the defect magnetic flux leakage signal is of great significance for magnetic flux leakage detection and defect evaluation. [0003] In the existing related technologi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N27/83G06F17/14
CPCG01N27/83G06F17/14G01R33/02
Inventor 黄松岭赵伟彭丽莎于佳
Owner TSINGHUA UNIV
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