Reconstruction of complex shaped crack from ECT signals based on a fast forward solver using an advanced multi-media element

2020 ◽  
Vol 64 (1-4) ◽  
pp. 621-629
Author(s):  
Yingsong Zhao ◽  
Cherdpong Jomdecha ◽  
Shejuan Xie ◽  
Zhenmao Chen ◽  
Pan Qi ◽  
...  
Keyword(s):  
Coefficient Matrix ◽  
Crack Edge ◽  
Numerical Accuracy ◽  
Gauss Point ◽  
Current Testing ◽  
Efficient Simulation ◽  
Shaped Crack ◽  
Multi Media ◽  
Profile Reconstruction ◽  
Crack Profile

In this paper, the conventional database type fast forward solver for efficient simulation of eddy current testing (ECT) signals is upgraded by using an advanced multi-media finite element (MME) at the crack edge for treating inversion of complex shaped crack. Because the analysis domain is limited at the crack region, the fast forward solver can significantly improve the numerical accuracy and efficiency once the coefficient matrices of the MME can be properly calculated. Instead of the Gauss point classification, a new scheme to calculate the coefficient matrix of the MME is proposed and implemented to upgrade the ECT fast forward solver. To verify its efficiency and the feasibility for reconstruction of complex shaped crack, several cracks were reconstructed through inverse analysis using the new MME scheme. The numerical results proved that the upgraded fast forward solver can give better accuracy for simulating ECT signals, and consequently gives better crack profile reconstruction.

Efficient numerical simulation of DC potential drop signals for application to NDT of metallic foam

2013 ◽  
Vol 33 (1/2) ◽  
pp. 147-156 ◽  
Author(s):  
Xiaojuan Wang ◽  
Shejuan Xie ◽  
Yong Li ◽  
Zhenmao Chen
Keyword(s):  
Numerical Technique ◽  
Potential Drop ◽  
Coefficient Matrix ◽  
Metallic Foam ◽  
Integral Points ◽  
Content Type ◽  
Efficient Simulation ◽  
Nondestructive Testing Method ◽  
Element Matrix ◽  
Matrix Calculation

Purpose – Direct current potential drop (DCPD) testing is a potential nondestructive testing method for quality control of the metallic foam (MF). The purpose of this paper is to develop a numerical technique for the efficient simulation of the DCPD signals of MFs with defects with boundary of complicated shapes. Design/methodology/approach – The concept of multi-medium element (MME) is introduced to treat the boundary of complex-shaped defect. A classification scheme of Gauss integral points is also proposed to select the Gauss points that have to be taken into account in the integral calculation of the coefficient matrix of each MME. Findings – MME is suitable for simulation of DCPD signals due to defects in complicated shapes. The numerical method for calculating the element matrix of the MME is efficient and accurate. The experimental results support the proposed method positively. Research limitations/implications – The code developed in this paper is suitable for the simulation of DCPD signals of MF due to a planar defect. The code for 3D defect is still under development. Originality/value – The concept of MME introduced to deal with the simulation of DCPD signal due to defect with boundary of complicated shape, as well as the numerical technique for element coefficient matrix calculation. The developed method gives possible for the inversion of DCPD signals of complicated defect shape.

Fast crack profile reconstruction using pulsed eddy current signals

2013 ◽  
Vol 54 ◽  
pp. 37-44 ◽  
Author(s):  
Libing Bai ◽  
Gui Yun Tian ◽  
Anthony Simm ◽  
Shulin Tian ◽  
Yuhua Cheng
Keyword(s):  
Eddy Current ◽  
Pulsed Eddy Current ◽  
Profile Reconstruction ◽  
Crack Profile

Linear Visco-Resistive Computations of Magnetohydrodynamic Waves: I. The Code and Test Cases

1994 ◽  
Vol 144 ◽  
pp. 503-505
Author(s):  
R. Erdélyi ◽  
M. Goossens ◽  
S. Poedts
Keyword(s):  
Resonant Absorption ◽  
Numerical Code ◽  
Mhd Waves ◽  
Test Cases ◽  
Numerical Accuracy ◽  
Element Discretization ◽  
Flux Tubes ◽  
Magnetohydrodynamic Waves ◽  
Viscosity Coefficients ◽  
Magnetic Flux Tubes

AbstractThe stationary state of resonant absorption of linear, MHD waves in cylindrical magnetic flux tubes is studied in viscous, compressible MHD with a numerical code using finite element discretization. The full viscosity tensor with the five viscosity coefficients as given by Braginskii is included in the analysis. Our computations reproduce the absorption rates obtained by Lou in scalar viscous MHD and Goossens and Poedts in resistive MHD, which guarantee the numerical accuracy of the tensorial viscous MHD code.

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