Model-Based Reconstruction of 2D Geometrical Features using Eddy Current Testing

It is important to improve the reliability of the eddy current non-destructive testing. It is generally difficult to reduce the probability of non-detection and the number of false alarms same time. Model Based Measurement (MBM), including estimation of state, failure diagnosis and trend analysis, has excellent results on general estimation. Actual results of MBM vary with the application domain, mathematical model and data processing. The time series model is a description of system in time domain based on equivalent output. The Kalman filter is an efficient method for suppressing the disturbance and improving the state estimation. A new method, called as eddy current testing (ECT) using a model based measurement, is presented. Two time series models are used for the normal status and the abnormal status in ECT. The Kalman filter on these models is applied to give useful information for decision making. Results of the experiment on aluminum plates demonstrate that this method is useful to improve the detection reliability.

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Probabilistic evaluation of detection capability of eddy current testing to inspect pitting on a stainless steel clad using multiple signal features

International Journal of Applied Electromagnetics and Mechanics ◽

10.3233/jae-209306 ◽

2020 ◽

Vol 64 (1-4) ◽

pp. 47-55

Author(s):

Takuma Tomizawa ◽

Haicheng Song ◽

Noritaka Yusa

Keyword(s):

Stainless Steel ◽

Eddy Current ◽

Pressure Vessels ◽

Eddy Current Testing ◽

Probability Of Detection ◽

Current Testing ◽

Multiple Signal ◽

Signal Features ◽

Inner Surface ◽

Drill Holes

This study proposes a probability of detection (POD) model to quantitatively evaluate the capability of eddy current testing to detect flaws on the inner surface of pressure vessels cladded by stainless steel and in the presence of high noise level. Welded plate samples with drill holes were prepared to simulate corrosion that typically appears on the inner surface of large-scale pressure vessels. The signals generated by the drill holes and the noise caused by the weld were examined using eddy current testing. A hit/miss-based POD model with multiple flaw parameters and multiple signal features was proposed to analyze the measured signals. It is shown that the proposed model is able to more reasonably characterize the detectability of eddy current signals compared to conventional models that consider a single signal feature.

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Non-destructive testing. Pulsed eddy current testing of ferromagnetic metallic components

10.3403/30334084 ◽

2017 ◽

Keyword(s):

Eddy Current ◽

Eddy Current Testing ◽

Non Destructive Testing ◽

Destructive Testing ◽

Current Testing ◽

Pulsed Eddy Current ◽

Non Destructive

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Non-destructive testing - Eddy current testing - Vocabulary

10.3403/30376407 ◽

2019 ◽

Keyword(s):

Eddy Current ◽

Eddy Current Testing ◽

Non Destructive Testing ◽

Destructive Testing ◽

Current Testing ◽

Non Destructive

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Copper and copper alloys - Eddy current testing on the outer surface of rods, bars, hollow rods and wires for the detection of defects by encircling test coil

10.3403/30373114u ◽

2019 ◽

Keyword(s):

Eddy Current ◽

Outer Surface ◽

Copper Alloys ◽

Eddy Current Testing ◽

Current Testing ◽

Detection Of Defects

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Copper and copper alloys - Eddy current testing on the outer surface of rods, bars, hollow rods and wires for the detection of defects by encircling test coil

10.3403/30373114 ◽

2019 ◽

Keyword(s):

Eddy Current ◽

Outer Surface ◽

Copper Alloys ◽

Eddy Current Testing ◽

Current Testing ◽

Detection Of Defects

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Research on Detection Mechanism of Weld Defects of Carbon Steel Plate Based on Orthogonal Axial Eddy Current Probe

Sensors ◽

10.3390/s20195515 ◽

2020 ◽

Vol 20 (19) ◽

pp. 5515

Author(s):

Linnan Huang ◽

Chunhui Liao ◽

Xiaochun Song ◽

Tao Chen ◽

Xu Zhang ◽

...

Keyword(s):

Carbon Steel ◽

Eddy Current ◽

Steel Plate ◽

Difficult Problem ◽

Eddy Current Testing ◽

Detection Sensitivity ◽

Detection Mechanism ◽

Current Testing ◽

Weld Defects ◽

Lift Off

The uneven surface of the weld seam makes eddy current testing more susceptible to the lift-off effect of the probe. Therefore, the defect of carbon steel plate welds has always been a difficult problem in eddy current testing. This study aimed to design a new type of eddy current orthogonal axial probe and establish the finite element simulation model of the probe. The effect of the probe structure, coil turns, and coil size on the detection sensitivity was simulated. Further, a designed orthogonal axial probe was used to conduct a systematic experiment on the weld of carbon steel specimens, and the 0.2 mm width and 1 mm depth of weld defects of carbon steel plates were effectively detected. The experimental results showed that the new orthogonal axial eddy current probe effectively suppressed the unevenness effect of the weld surface on the lift-off effect during the detection process.

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Evaluation of Coating Thickness Using Lift-Off Insensitivity of Eddy Current Sensor

Sensors ◽

10.3390/s21020419 ◽

2021 ◽

Vol 21 (2) ◽

pp. 419

Author(s):

Xiaobai Meng ◽

Mingyang Lu ◽

Wuliang Yin ◽

Abdeldjalil Bennecer ◽

Katherine J. Kirk

Keyword(s):

Eddy Current ◽

Coating Thickness ◽

Thickness Measurement ◽

Eddy Current Testing ◽

Thickness Variation ◽

Testing Technique ◽

Current Testing ◽

Thin Skin ◽

Embedded Algorithms ◽

Lift Off

Defect detection in ferromagnetic substrates is often hampered by nonmagnetic coating thickness variation when using conventional eddy current testing technique. The lift-off distance between the sample and the sensor is one of the main obstacles for the thickness measurement of nonmagnetic coatings on ferromagnetic substrates when using the eddy current testing technique. Based on the eddy current thin-skin effect and the lift-off insensitive inductance (LII), a simplified iterative algorithm is proposed for reducing the lift-off variation effect using a multifrequency sensor. Compared to the previous techniques on compensating the lift-off error (e.g., the lift-off point of intersection) while retrieving the thickness, the simplified inductance algorithms avoid the computation burden of integration, which are used as embedded algorithms for the online retrieval of lift-offs via each frequency channel. The LII is determined by the dimension and geometry of the sensor, thus eliminating the need for empirical calibration. The method is validated by means of experimental measurements of the inductance of coatings with different materials and thicknesses on ferrous substrates (dual-phase alloy). The error of the calculated coating thickness has been controlled to within 3% for an extended lift-off range of up to 10 mm.

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