Novel austenitic steel ageing classification method using eddy current testing and a support vector machine

Measurement ◽  
2018 ◽  
Vol 127 ◽  
pp. 98-103 ◽  
Author(s):  
Mónica P. Arenas ◽  
Tiago J. Rocha ◽  
Chandra S. Angani ◽  
Artur L. Ribeiro ◽  
Helena G. Ramos ◽  
...  
Keyword(s):  
Support Vector Machine ◽  
Austenitic Steel ◽  
Eddy Current ◽  
Eddy Current Testing ◽  
Classification Method ◽  
Support Vector ◽  
Current Testing

The combination of adaptive database SDM and multi-output SVM for eddy current testing

2015 ◽  
Vol 34 (6) ◽  
pp. 1731-1739 ◽  
Author(s):  
M. Chelabi ◽  
T. Hacib ◽  
Z. Belli ◽  
M. R. Mekideche ◽  
Y. Le Bihan
Keyword(s):  
Eddy Current ◽  
Eddy Current Testing ◽  
Learning Performance ◽  
Support Vector ◽  
Inversion Method ◽  
Defect Characterization ◽  
Content Type ◽  
Current Testing ◽  
Svm Model ◽  
Schema Design

Purpose – Eddy current testing (ECT) is a nondestructive testing method for the detection of flaws that uses electromagnetic induction to find defects in conductive materials. In this method, eddy currents are generated in a conductive material by a changing magnetic field. A defect is detected when there is a disruption in the flow of the eddy current. The purpose of this paper is to develop a new noniterative inversion methodology for detecting degradation (defect characterization) such as cracking, corrosion and erosion from the measurement of the impedance variations. Design/methodology/approach – The methodology is based on multi-output support vector machines (SVM) combined with the adaptive database schema design method (SDM). The forward problem was solved numerically using finite element method (FEM), with its accuracy experimentally verified. The multi-output SVM is a statistical learning method that has good generalization capability and learning performance. FEM is used to create the adaptive database required to train the multi-output SVM and the genetic algorithm is used to tune the parameters of multi-output SVM model. Findings – The results show the applicability of multi-output SVM to solve eddy current inverse problems instead of using traditional iterative inversion methods which can be very time-consuming. With the experimental results the authors demonstrate the accuracy which can be provided by the multi-output SVM technique. Practical implications – The work allows extending the capability of the experimentation ECT defect characterization system developed at LGEP. Originality/value – A new inversion method is developed and applied to ECT defect characterization. This new concept introduces multi-output SVM in the context of ECT. The real data together with estimated one obtained by multi-output SVM model are compared in order to evaluate the effectiveness of the developed technique.

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.

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