3D Eddy Current Testing by FEM for Detection of Crack’s in Materials

2016 ◽  
Vol 703 ◽  
pp. 349-353 ◽  
Author(s):  
Kahina Chabane ◽  
Salaheddine Harzallah ◽  
Mohamed Chabaat
Keyword(s):  
Eddy Current ◽  
Eddy Currents ◽  
Numerical Approach ◽  
Governing Equations ◽  
Finite Element Discretization ◽  
Magnetic Vector ◽  
Element Discretization ◽  
Current Testing ◽  
Micro Cracks ◽  
Set Up

In this paper, we present a nondestructive Testing by sensor Eddy current is used as a tool to control cracks and micro-cracks in materials. A new method for computing by measuring and testing related 3D Eddy currents is considered. In the process, a Potential Magnetic Vector is provided on the basis of formulations taken from the theoretical set up. Thus, results of relevant applications are obtained to check the theory consistency. A simulation by a numerical approach using Finite element discretization of 3-D Eddy Current governing equations is employed to detect cracks and damaged zones in materials and eventually to study their propagation.

Formulation for Stress Intensity Factors and J-Integral Calculation by Eddy Current Testing

2015 ◽  
Vol 660 ◽  
pp. 225-230 ◽  
Author(s):  
Salaheddine Harzallah ◽  
Mohamed Chabaat ◽  
Sekoura Benissad
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Eddy Current ◽  
Eddy Currents ◽  
J Integral ◽  
Intensity Factors ◽  
Magnetic Vector ◽  
Current Testing ◽  
Set Up

In this paper, we present a method for computing the Stress Intensity Factor (SIF) and J-Integral, by measuring and testing related Eddy currents. In the process, we provide a magnetic vector based formulations for the theoretical set up. Furthermore, we provide relevant applications having theory consistent results.

3D-FEM computation and experimental study of eddy currents for characterization of surface cracks

2017 ◽  
Vol 8 (5) ◽  
pp. 603-610 ◽  
Author(s):  
Salaheddine Harzallah ◽  
Mohamed Chabaat
Keyword(s):  
Finite Element ◽  
Eddy Current ◽  
Eddy Currents ◽  
Research Work ◽  
Main Idea ◽  
Shape Reconstruction ◽  
Finite Element Discretization ◽  
3D Fem ◽  
Element Discretization ◽  
Content Type

Purpose The purpose of this paper is to present a new approach for computing by measuring and testing related 3D Eddy currents. In the process, a magnetic vector is formulated from the theoretical setup and obtained results from relevant applications are checked for the consistency of the theory. Besides, cracks detection as well as its propagation is studied through the two parameters: SIF and J-integral. A simulation by a numerical approach using finite-element discretization of 3D governing equations is employed to detect damaged zones and cracks. This approach has been used in the aircraft industry to control cracks. Besides, it makes it possible to highlight the defects of parts while preserving the integrity of the controlled products. Obtained results are compared and agreed with those of other researchers. Design/methodology/approach Finite-element discretization of 3D for solving problem in eddy current testing is presented in this paper. The main idea is the introduction of categorization for the shape reconstruction using the non-destructive testing by 3D-EC. The results are presented for a simple eddy current problem using the finite-element method as an experimental support. Findings In this research work, results of the various cases of simulation have been obtained. From these results of various boxes of simulation, one can conclude that the calculation of the impedance in only one point is not enough to confirm the presence or the absence of a defect for materials. Then, this confirmation leads us to the calculation of the impedance along the plate. The detection of an external defect requires the energy of the sensor by high frequencies .The position of defect (internal, in the middle, external) has a large effect on the impedance. The use of this sensor type in industrial application is frequent because of its precision (minimal error) and its low costs. The major disadvantage of this type of sensor lies in the fact that it is unable to detect a defect. Originality/value This paper fulfills an identified need to detect cracks in materials and eventually to study their propagation.

Limit Loads for Structural Elements Made of Heterogeneous Materials

2012 ◽  
Author(s):  
Min Chen ◽  
Abdelkader Hachemi ◽  
Dieter Weichert
Keyword(s):  
Material Properties ◽  
Large Scale ◽  
Numerical Approach ◽  
Interior Point Algorithm ◽  
Structural Elements ◽  
Finite Element Discretization ◽  
Element Discretization ◽  
Limit Loads ◽  
Heterogeneous Structures ◽  
Conforming Finite Element

A numerical method is presented for determining the limit loads of periodically heterogeneous structures subjected to variable loads. The Melan’s lower-bound shakedown theorem was applied to representative volume elements. Combined with the homogenization technique, the homogenized material properties were determined through transformation from the mesoscopic to macroscopic admissible loading domains. For the numerical applications, solid non-conforming finite element discretization and large-scale nonlinear optimization, based on an interior-point-algorithm were used. The methodology is illustrated by the application to pipes models. This way, the proposed method provides a direct numerical approach to evaluate the macroscopic strength of heterogeneous structures with periodic micro- or meso-structure as a useful tool for the design of structures.

scholarly journals Comparison of defect detection limits in Lorentz force eddy current testing and classical eddy current testing

2018 ◽  
Vol 7 (2) ◽  
pp. 453-459 ◽  
Author(s):  
Jan Marc Otterbach ◽  
Reinhard Schmidt ◽  
Hartmut Brauer ◽  
Marek Ziolkowski ◽  
Hannes Töpfer
Keyword(s):  
Lorentz Force ◽  
Defect Detection ◽  
Eddy Current ◽  
Eddy Currents ◽  
Excitation Frequency ◽  
Detection Limits ◽  
Eddy Current Testing ◽  
Current Testing ◽  
Testing Method ◽  
Measurement Results

Abstract. Lorentz force eddy current testing (LET) is a motion-induced eddy current testing method in the framework of nondestructive testing. In this study, we address the question of how this method is classified in comparison with a commercial eddy current testing (ECT) measurement device ELOTEST N300 in combination with the probe PKA48 from Rohmann GmbH. Therefore, measurements using both methods are performed and evaluated. Based on the measurement results, the corresponding defect detection limits, i.e., up to which depth the defect can be detected, are determined and discussed. For that reason, the excitation frequency spectrum of the induced eddy currents in the case of LET is considered.

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