Simulation and Numerical Analysis of Nondestructive Testing on Weld Cracks by Eddy Current Thermography

2014 ◽  
Vol 1061-1062 ◽  
pp. 874-880
Author(s):  
Lei Jiang ◽  
Zhi Ping Liu ◽  
Xing Le Liu ◽  
Ge Lu
Keyword(s):  
Eddy Current ◽  
Excitation Frequency ◽  
Reference Value ◽  
Inspection System ◽  
Surface Cracks ◽  
Large Area ◽  
Element Analysis ◽  
Testing Method ◽  
Non Destructive

Eddy current thermography is an emerging non-destructive method for detection and characterization of surface cracks in conductive specimen over a relatively large area. In this paper, the weld crack testing method based on eddy current thermography was proved to be feasible through studying the influence of inductor orientation, excitation frequency and crack length, depth, width on the surface temperature distribution using finite element analysis software COMSOL Multiphysics4.3b. The findings show that the quantitative evaluation is more viable according to the optimized parameters. This method has a certain reference value for quantitative analysis and designing inspection system with eddy current stimulated approach.

Optimum eddy current excitation frequency for subsurface defect detection in SQUID based non-destructive evaluation

2010 ◽  
Vol 43 (8) ◽  
pp. 713-717 ◽  
Author(s):  
R. Nagendran ◽  
N. Thirumurugan ◽  
N. Chinnasamy ◽  
M.P. Janawadkar ◽  
R. Baskaran ◽  
...  
Keyword(s):  
Defect Detection ◽  
Eddy Current ◽  
Excitation Frequency ◽  
Non Destructive Evaluation ◽  
Subsurface Defect ◽  
Non Destructive

Characterization of the Wear in the Turbojet Fins

2015 ◽  
Vol 640 ◽  
pp. 29-34
Author(s):  
Zohra Labed ◽  
Djamel Guechi ◽  
Necib Brahim
Keyword(s):  
Fatigue Damage ◽  
Eddy Current ◽  
Non Destructive ◽  
Non Destructive Techniques

The wear is very difficult to characterize because of its complexity and its measurement phenomenon. Our work is to prepare samples Fan blades, worn, to determine the nature of the wear and damage them. For these reasons, the characterization of these samples was conducted in different microscopic and macroscopic scales. We used non-destructive techniques such as eddy current and penetrant methods. The results obtained allowed us to see the deterioration of fins from one floor to another. These results are directly related to the effects of mechanical, thermal and pressure. It has been, in addition to detecting a different type of damage these fan blades that is the fatigue damage.

Simulation of Non-Destructive Testing on Weld Surface Crack of Metal Structure by Electromagnetically Stimulated Infrared Thermography

2014 ◽  
Vol 590 ◽  
pp. 639-644
Author(s):  
Zhi Ping Liu ◽  
Hui Long Liu ◽  
Lei Jiang ◽  
Ge Lu
Keyword(s):  
Infrared Thermography ◽  
Surface Crack ◽  
Paint Film ◽  
Excitation Frequency ◽  
Reference Value ◽  
Metal Structure ◽  
Electromagnetic Excitation ◽  
Element Analysis ◽  
Welded Structure ◽  
Abnormal Temperature

With the wider use of metal welded structure in engineering machine, on-line inspection on weld crack is of great significance. This paper reports an emerging nondestructive approach----electromagnetically stimulated infrared thermography technique, for the detection and characterization of surface cracks. According to the electromagnetic thermal coupling analysis theory, different abnormal temperature field distributions caused by various crack dimensions , coil lifting heights, stimulated frequencies and paint film thickness were obtained, via 3D finite element analysis (FEA).The results show that the weld surface crack detectability are greatly influenced by the crack width and the paint layer thickness, with coil life-off height decreasing and electromagnetic excitation frequency increasing, the maximum abnormal temperature difference increases. There is a certain reference value for further research on the design of the electromagnetically stimulated control device.

Electron Channeling Contrast Imaging for Beyond Silicon Materials Characterization

2018 ◽  
Author(s):  
Libor Strakos ◽  
Ondrej Machek ◽  
Tomas Vystavel ◽  
Andreas Schulze ◽  
Han Han ◽  
...  
Keyword(s):  
Lattice Mismatch ◽  
Defect Density ◽  
Analytical Techniques ◽  
Device Performance ◽  
Contrast Imaging ◽  
Large Area ◽  
Electron Channeling ◽  
Silicon Materials ◽  
Non Destructive

Abstract As semiconductor devices continue to shrink, novel materials (e.g. (Si)Ge, III/V) are being tested and incorporated to boost device performance. Such materials are difficult to grow on Si wafers without forming crystalline defects due to lattice mismatch. Such defects can decrease or compromise device performance. For this reason, non-destructive, high throughput and reliable analytical techniques are required. In this paper Electron Channeling Contrast Imaging (ECCI), large area mapping and defect detection using deep learning are combined in an analytical workflow for the characterization of the defectivity of “beyond Silicon” materials. Such a workflow addresses the requirements for large areas 10-4 cm2 with defect density down to 104 cm-2.

Qualification of a Frequency Scanning Eddy Current Equipment for Nondestructive Characterization of New and Serviced High-Temperature Coatings

2001 ◽  
Author(s):  
Giampiero Antonelli ◽  
Paola Crisafulli ◽  
Giacomo Tirone
Keyword(s):  
High Temperature ◽  
Eddy Current ◽  
Gas Turbines ◽  
Structural Damage ◽  
Economic Losses ◽  
Thermal Barriers ◽  
Frequency Scanning ◽  
Non Destructive ◽  
Equipment Qualification

As modern gas turbines are continuously being upgraded, mainly through the increase of their firing temperature and cooling optimization, the prime protection of the high technology and high-cost hot gas path parts is increasingly being transferred to the coatings. In order to avoid the risk of structural damage of these components, with its potential for greater economic losses — mostly traceable to unexpected prime time outages — refurbishment cycle should be dictated by the amount of the life actually expended by the coating. To address the issues of quality and condition assessment of new and serviced high-temperature coatings applied on buckets and vanes, an innovative non-destructive system was developed based on a frequency scanning eddy current technique. It combines outstanding high frequency hardware with model based analysis of raw data. In the paper, quantitative data on equipment qualification are presented, relating to its capability in measuring both the thickness and β-aluminide depletion of MCrAlY coatings applied on Ni-base superalloys. The results of an inspection campaign on serviced blades, performed during major overhauls of ENEL gas turbines, will also be reported, together with recent system upgrades, aiming at extending its applicability to newer coatings such as thermal barriers and over-aluminized MCrAlY’s.

Inverse Problems Using Neural Networks for Cracks Characterization in Materials

2015 ◽  
Vol 660 ◽  
pp. 361-365 ◽  
Author(s):  
Salaheddine Harzallah ◽  
Mohamed Chabaat ◽  
Sekoura Benissad
Keyword(s):  
Neural Networks ◽  
Eddy Current ◽  
Current Problem ◽  
Research Work ◽  
Excitation Frequency ◽  
Theoretical Problem ◽  
Probe Position ◽  
Impedance Measurements ◽  
Eddy Current Problem

Inverse eddy current problem using Artificial Neural Networks (ANN) approach for the localization and the classification shape of defects is considered. The task of reconstructing the cracks and damage in the plate profile of an inspected specimen in order to estimate its material properties can be described in this research work. This is accomplished by inverting eddy current probe impedance measurements that are recorded as a function of probe position, excitation frequency or both. In eddy current nondestructive evaluation, this is widely recognized as a complex theoretical problem whose solution is likely to have a significant impact on the characterization of cracks in materials .

scholarly journals Study on Effect of Electromagnetic Characteristics of Deformed 304 Stainless Steel on Eddy Current Testing

2020 ◽  
Author(s):  
Benli Wan ◽  
Bin Hu ◽  
Yuntao Li ◽  
Yuhong Zhu
Keyword(s):  
Stainless Steel ◽  
Eddy Current ◽  
Magnetic Permeability ◽  
Excitation Frequency ◽  
Eddy Current Testing ◽  
304 Stainless Steel ◽  
Electromagnetic Response ◽  
Element Analysis ◽  
Current Testing ◽  
304 Austenitic Stainless Steel

The induced ferrite and other high magnetic microstructures content changes are studied when 304 austenitic stainless steel stripe specimens are tested under different uniaxial tension deformation, namely its deformation less than 50%. Furtherly, the correlation is plotted between the resulting magnetic permeability or coercivity caused by these microstructures and deformation. Meanwhile, the optimal eddy current excitation frequency under different deformation was obtained, which was consistent with 3-D finite element analysis (FEA). Besides, other various factors affecting the quality of eddy current testing (ECT), such as temperature and conductivity, are also considered comprehensively during the tensile test. The results of the experiment and simulation calculation show that when the deformation is within 50% that necking deformation has occurred, the magnetic permeability of specimens increases with deformation, and gradually begin to have the magnetic properties of weak ferromagnetic materials, which also changes the optimal excitation frequency, which varies from 60 kHz to 110 kHz. Because of the electromagnetic response noise increase, the impedance plane diagrams of defects distort simultaneously, which leads to the quantitative evaluation error of defects.

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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