A Study on the Signal Correction for Multiple Defects in MFL Type Nondestructive Testing System Park, Jeng Hoon; Kim, Hui Min; Park, Gwan Soo;
MFL (Magnetic flux leakage) type nondestructive testing has been used for inspection of underground gas pipelines to find metal defects by detecting magnetic leakage signal. Because the underground gas pipeline is exposed by environment such as high pressure with great humidity, external defects are easily formed on the surface of pipelines and they are being grouped respectively. These adjacent defects cause the signal distortion of leakage flux so that it is hard to estimate the shape information of defects. In this paper, we performed to study of the signal distortion and compensating method for multiple defects in MFL type nondestructive testing system by using 3D FEM simulation. This paper proposes the basic algorithm of defect signal analysis on multiple defects on the surface of 30 inch diameter pipeline.
magnetic flux leakage testing;nondestructive testing;pipeline;multiple defects;finite elements method;MFL;
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