Precise eddy current impedance measurement of metal plates

2011 ◽  
pp. 51-54
Keyword(s):  
Eddy Current ◽  
Impedance Measurement ◽  
Metal Plates

A Method Using Magnetic Eddy Current Testing for Distinguishing ID and OD Defects of Pipelines under Saturation Magnetization

2020 ◽  
Vol 35 (9) ◽  
pp. 1089-1098
Author(s):  
Yue Long ◽  
Songling Huang ◽  
Yang Zheng ◽  
Shen Wang ◽  
Wei Zhao
Keyword(s):  
Saturation Magnetization ◽  
Eddy Current ◽  
Oil And Gas ◽  
Impedance Measurement ◽  
Eddy Current Testing ◽  
Current Testing ◽  
Pipeline Inspection ◽  
Field Environment ◽  
Physical Experiments ◽  
Essential Problem

Distinguishing the inside (ID) and outside (OD) defect is an essential problem for the oil and gas pipeline nondestructive testing in engineering. The most widely used solution is to combine a magnetic flux leakage (MFL) section and a second section. For the strong magnetic field environment of the MFL, the second section and the MFL section are usually located at different mechanical positions, which leads to an increase in the length of the pipeline inspection gauge (PIG) and a decrease in the reliability. In this paper, a new impedance measurement method and the concept of the defect impedance angle are proposed to distinguish the ID and OD defects of pipelines under saturation magnetization, which based on the magnetic eddy current testing (MECT). The proposed ID & OD detection method can work with the MFL in the same mechanical position. Meanwhile, the proposed method also has the advantage that the discrimination criteria of the ID and OD defect keeps consistent with the classic eddy current testing (ECT). Furthermore, the robustness and sensitivity of the proposed method are discussed and verified by physical experiments.

scholarly journals Research on Eddy Current Imaging Detection of Surface Defects of Metal Plates Based on Compressive Sensing

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Weiquan Deng ◽  
Bo Ye ◽  
Guoyong Huang ◽  
Jiande Wu ◽  
Mengbao Fan ◽  
...  
Keyword(s):  
Compressive Sensing ◽  
Eddy Current ◽  
Surface Defects ◽  
Sparse Representations ◽  
Signal Recovery ◽  
Transform Domain ◽  
Main Research ◽  
Metal Plates ◽  
Domain Mapping ◽  
Eddy Current Imaging

Accurate detection and quantitative evaluation of defects and damage in metal plates is a crucial task in a range of technological applications, such as maintaining the integrity, enhancing the safety, and assuring the reliability of structures. There is scope for improving eddy current testing methods by incorporating compressive sensing (CS) in the inspection process. The key scientific problems in eddy current imaging of defects of metal plates are sparse representations and transform domain mapping, sparse testing constraints, and sparse image reconstruction. The main research content of this paper is as follows. We first provide basic theory based on research of sparse representations, transform domain mapping, sparse matrices, sparse transform matrices, and signal recovery a priori errors. We then propose information-recovery methods for completing compressive sensing. Third, we establish an experimental system for validating theories and methods. Finally, we establish theories and methods for eddy current imaging of metal plates.

THICKNESS MEASUREMENT OF ALUMINUM PLATES WITH A PULSED EDDY CURRENT METHOD

2008 ◽  
Vol 22 (11) ◽  
pp. 911-915 ◽  
Author(s):  
YOUNG JOO KIM ◽  
BONG YOUNG AHN ◽  
SEUNG-SEOK LEE ◽  
YOUNG-KIL SHIN
Keyword(s):  
Eddy Current ◽  
Current Method ◽  
Thickness Measurement ◽  
Eddy Current Method ◽  
Digital Oscilloscope ◽  
Pulsed Eddy Current ◽  
Metal Plates ◽  
Exciting Coil ◽  
Aluminum Plates ◽  
A Current

In this study, coil sensors that are used with a pulsed eddy current (PEC) were designed and fabricated. The proposed sensor is a differential send-receive type that eliminates the voltage induced by the direct field from the exciting coil in a PEC probe. The signal from the sensing coil is generated only on a metal specimen. For the experiment, various metal plates of different conductivities and aluminum plates of different thicknesses from 1 mm to 25 mm were prepared. A voltage square pulse was applied to an exciting coil, and the output from the sensing coil was captured by a digital oscilloscope. The applied voltage was approximately 20 volts at its greatest with a current peak of approximately 15 amperes. A 10% variation of the thickness of an aluminum plate of 20 millimeter thick was measured.

A Data Standardization and Reconstruction Method for Magnetic Induction Tomography

2013 ◽  
Vol 647 ◽  
pp. 560-565 ◽  
Author(s):  
Qiang Du ◽  
Bao Dong Bai ◽  
Li Ke
Keyword(s):  
Eddy Current ◽  
Magnetic Induction ◽  
Impedance Measurement ◽  
Reconstruction Algorithm ◽  
Biological Tissues ◽  
Measured Data ◽  
Image Resolution ◽  
Reconstruction Method ◽  
Data Standardization ◽  
Magnetic Induction Tomography

Magnetic induction tomography (MIT) is a biologic tomography technology, which is to obtain the conductivity distribution by detecting the data on the boundary of the imaging area based on the eddy current principle. The small impedance difference between biological tissues makes the eddy current weak, and it leads to a direct effect on the biological impedance measurement and imaging sensitivity. A measured data standardization method is presented in this paper for enhancing the measured data sensitivity, and combined with the back-projection reconstruction algorithm to get reconstruction image. It is applied to a variety of measurement and the simulation experiment based on the calculation results of finite-element methods. The reconstructed images indicate that the method can improve the image resolution and sensitivity, and which provides an effective data standardization and reconstruction algorithm for the magnetic induction tomography.

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