Investigation of Rotating Eddy Current Testing Simulation Using Simplified Model

2021 ◽  
Author(s):  
Chenkai Yang ◽  
Jiuhao Ge ◽  
Baowang Hu
Keyword(s):  
Simulation Model ◽  
Eddy Current ◽  
Crack Depth ◽  
Eddy Current Testing ◽  
Simplified Model ◽  
Current Testing ◽  
Application Condition ◽  
Exciting Frequency ◽  
Text Signal ◽  
Peak Value

To reduce the time of simulation for rotating Eddy current testing (RECT) technique, a simplified model without modeling probe was proposed previously. However, the applicability of the simplified simulation model was unknown. In this paper, the applicability of the simplified model for the RECT technique was investigated. The application condition of the simplified model was provided by comparing it with the results of the traditional simulation model. The simplified model was suitable for the study of cracks shorter than 70% size of the uniform Eddy current induced by the probe in a traditional model or experiment. The experiment was conducted to validate the simplified model. Moreover, using the simplified model, the effects of crack depth, orientation, and exciting frequency were studied. The deeper the crack depth was, the greater peak value of [Formula: see text] signal was. The crack angle was linear with the phase of signal. The exciting frequency affected the amplitude and phase of the signal at the same time.

Crack Sizing of Deep Cracks in Eddy Current Testing Using 3D Electromagnetic Field Analysis

2004 ◽  
Author(s):  
Toshiyuki Takagi ◽  
Tetsuya Uchimoto ◽  
Hisashi Endo
Keyword(s):  
Eddy Current ◽  
Crack Depth ◽  
High Accuracy ◽  
Eddy Current Testing ◽  
Field Analysis ◽  
Current Field ◽  
Metal Structures ◽  
Current Testing ◽  
Crack Sizing ◽  
Exhaustive Study

A computer-aided approach of the eddy current testing (ECT) is described to detect and to size up deep cracks in thick metal structures. A 3D eddy current field analysis based on the finite elements performs designing ECT probes and evaluating the size of crack depth quantitatively. An exhaustive study on the ECT probe specification gives the optimal design of coil elements and their combination. The experimental verification shows that the developed ECT probe employing double exciting coils is capable of detecting crack depth over 10mm from the inspection surfaces. The depth of cracks is quantitatively evaluated from the measured ECT signals with the help of numerical calculation. The results of evaluation profile the crack shapes with fairly high accuracy, supporting our approach.

Enhance the Sensibility of the Resonance Type Eddy Current Testing

2014 ◽  
Vol 792 ◽  
pp. 72-77
Author(s):  
Kouki Maruyama ◽  
Illiana Marinova ◽  
Yoshifuru Saito
Keyword(s):  
Resonant Frequency ◽  
Eddy Current ◽  
Resonance Curve ◽  
Eddy Current Testing ◽  
Metallic Materials ◽  
Impedance Sensing ◽  
Current Testing ◽  
Frequency Selection ◽  
Exciting Frequency ◽  
Nondestructive Testing Methods

Eddy current testing (ECT) is one of the most representative nondestructive testing methods for metallic materials, parts, structures and so on. This paper proposes improvement of sensibility of the impedance sensing type ECT. Sensibility of the ECT is improved by means of three steps. One is an optimum exciting frequency selection. We employ the natural parallel resonant frequency of ECT coil. The second is to increase the sharpness of the resonance curve on impedance versus frequency characteristic by changing the coil connection. Finally, we attach externally capacitor to reduce the resonance frequency into low. This makes it possible to enhance the sensibility of the impedance sensing type ECT operating at the resonant frequency.

Sizing of natural crack using multi-output support vector regression method from multi-frequency eddy current testing signals

2020 ◽  
Vol 64 (1-4) ◽  
pp. 721-728
Author(s):  
Li Wang ◽  
Zhenmao Chen
Keyword(s):  
Support Vector Regression ◽  
Quantitative Evaluation ◽  
Eddy Current ◽  
Crack Depth ◽  
Eddy Current Testing ◽  
Support Vector ◽  
Efficient Operation ◽  
Current Testing ◽  
Multiple Parameters ◽  
Equipment Sizing

In the nondestructive evaluation for components of key equipment, sizing of natural crack is important in order to guarantee both the safety and efficient operation for large mechanical systems. Natural cracks have complex boundary and there may be electric current flowing through crack faces. If a simple model of artificial notch is used to simulate it, errors often occur in crack depth reconstruction from eddy current testing (ECT) signals. However, if a complex crack conductivity model is used, quantitative evaluation of natural crack will be transformed into a multivariable nonlinear optimization problem and the solution is difficult. In this paper, based on the relationship between crack parameters and features of multi-frequency ECT signals, a multi-output support vector regression algorithm using domain decomposition for parameters was proposed. The algorithm realized the quantitative evaluation of multiple parameters of crack in turn. Numerical examples with simulated and measured ECT signals were presented to verify the efficiency of the proposed strategy.

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

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.

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

Sensors ◽  
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.

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

Sensors ◽  
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.

Sign in / Sign up

Export Citation Format

Share Document