DEVELOPMENT OF SHIELDED REFLECTION TYPE PULSED EDDY CURRENT TESTING PROBES FOR THICKNESS EVALUATION

2008 ◽  
Vol 22 (11) ◽  
pp. 923-928
Author(s):  
YOUNG-KIL SHIN ◽  
DONG-MYUNG CHOI ◽  
KWAN-SEOB JANG
Keyword(s):  
Eddy Current ◽  
Pulse Width ◽  
Thickness Variation ◽  
Signal Pulse ◽  
Test Plate ◽  
Zero Crossing ◽  
Time To Peak ◽  
Pulsed Eddy Current ◽  
Crossing Time ◽  
Peak Value

Reflection and send-receive type probe shielded by ferrite is designed to evaluate the thickness of test plate by a pulsed eddy current (PEC) method and effects of pulse width to PEC signal are investigated when a 10.5 mm thick, nonmagnetic plate is inspected. Results show that the best sensitivity to thickness variation can be achieved by the peak value of a PEC signal. Pulse width variation study suggests that the shorter pulse width is desired if the peak value or the zero crossing time is used to evaluate the thickness, while the longer pulse width is needed if the time to peak value is used to evaluate it.

Review and Evaluation of Characterization First Return Stroke in the Measured Lightning Electric Fields on Malaysia Data

2015 ◽  
Vol 793 ◽  
pp. 44-48
Author(s):  
S.N.M. Arshad ◽  
Mohd Zainal Abidin Ab Kadir ◽  
Mahdi Izadi ◽  
A.M. Ariffen ◽  
M.N. Hamzah ◽  
...  
Keyword(s):  
Electric Fields ◽  
Rise Time ◽  
Statistical Correlation ◽  
Peak Time ◽  
Return Stroke ◽  
Zero Crossing ◽  
Time To Peak ◽  
Lightning Channel ◽  
Crossing Time

In this paper, the characterization of measured electric fields on first return stroke due to lightning channel was studied done. Likewise, previous studies on this case were discussed and reviewed accordingly. Furthermore, the first return stroke was analyzed done in detailed and was indicated on the real measured electric fields. Later the results were discussed appropriately. The behaviorsof first return stroke signal has beencharacterized from previous researchers. This study shows themeasured data in detailed, which include there are slow front time, first return stroke peak, time to peak, zero crossing time and 10% to 90% rise time. The characteristic of first return stroke signal data in Malaysia was compared with data gathered in Sweden. Moreover In addition, the statistical correlation between electric field zero times and corresponding rise times was also been studied.

Time-to-peak of time derivative signals of pulsed eddy current testing for evaluating the thickness of ferromagnetic samples

2021 ◽  
Vol 63 (2) ◽  
pp. 88-94
Author(s):  
Dongdong Wen ◽  
Shuchen Wang ◽  
Lei Zhang ◽  
Jianhua Zhang
Keyword(s):  
Eddy Current ◽  
Measurement Accuracy ◽  
Time Derivative ◽  
Thickness Measurement ◽  
Processing Method ◽  
Current Testing ◽  
Time To Peak ◽  
Pulsed Eddy Current ◽  
Precision Evaluation ◽  
Lift Off

The time-to-peak serves as a popular signal feature of pulsed eddy current (PEC) signals and is widely used in thickness measurement and defect detection. In order to further improve the ability of time-to-peak independent of the lift-off effect, a time derivative processing method is proposed in this paper to obtain a better time-to-peak feature of time derivative signals of PEC for reducing the lift-off effect. The method is used to improve the thickness measurement accuracy of ferromagnetic samples. The results of simulation and experimentation demonstrate that a time-to-peak feature of time derivative signals of PEC can be obtained using the time derivative processing method and the timeto-peak obtained from time derivative signals of PEC can be used to measure the thickness and improve the thickness measurement accuracy of ferromagnetic samples. This means that the use of the time-to-peak of time derivative signals of PEC is feasible for high-precision evaluation of the thickness of ferromagnetic samples.

Simultaneous measurement of thickness and lift-off using the tangential component of magnetic flux density in pulsed eddy current testing

2021 ◽  
Vol 63 (6) ◽  
pp. 341-347
Author(s):  
Hang Xu ◽  
Donglin Li ◽  
Tao Chen ◽  
Xiaochun Song
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Eddy Current ◽  
Tangential Component ◽  
Magnetic Flux Density ◽  
Logarithmic Scale ◽  
Time To Peak ◽  
Pulsed Eddy Current ◽  
Lift Off ◽  
Two Parameters

The pulsed eddy current (PEC) technique is commonly used in the petrochemical and power generation industries to measure two parameters: the degree of pipe wall corrosion and the thickness of the insulation shield. These two parameters can be evaluated by examining the thickness of conductive materials and the lift-off distance, respectively. To explore a possible technique for simultaneously measuring the thickness and the lift-off, the present study envisaged the development of a PEC testing method based on detecting the tangential component of the magnetic flux density. The tangential component of the magnetic flux density was excited by two racetrack-type coils injecting currents in opposite directions that were picked up by a magnetic sensor. The slope in logarithmic scale and the time-to-peak of the magnetic signal were verified to characterise the features of the thickness and the lift-off, respectively. By analysing the simulation and experimental results, the feasibility of simultaneously measuring the thickness and the lift-off was demonstrated.

The Pulsed Eddy Current Differential Probe to Detect a Thickness Variation in an Insulated Stainless Steel

2010 ◽  
Vol 29 (4) ◽  
pp. 248-252 ◽  
Author(s):  
C. S. Angani ◽  
D. G. Park ◽  
C. G. Kim ◽  
P. Leela ◽  
P. Kollu ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Eddy Current ◽  
Thickness Variation ◽  
Pulsed Eddy Current

Thickness Evaluation of Insulated Pipelines and Pressure Vessels Using Pulsed Eddy Current Technology

2012 ◽  
Author(s):  
Ehsan Shameli
Keyword(s):  
Nondestructive Evaluation ◽  
Eddy Current ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Pressure Vessels ◽  
Test Material ◽  
Gas Industry ◽  
Zero Crossing ◽  
Pulsed Eddy Current ◽  
Thickness Variations

Information about integrity of pipelines and pressure vessels is vital to the oil and gas industry. This emphasizes the need for fast and cost effective non-destructive testing solutions for monitoring and inspection of these components. However, due to reasons such as corrosion protection and temperature maintenance, pipelines and pressure vessels are usually coated throughout the oil and gas industry. These coatings also present a barrier to inspections and typically need to be removed prior to inspection with nondestructive evaluation (NDE) methods. This article presents a pulsed eddy current (PEC) system suitable for nondestructive evaluation of steel pipelines and pressure vessels without the need for removing the coating layers. A PEC probe was fabricated and a custom computer code with built in signal processing and data analysis functions was developed to collect the measurement signals and calculate thickness variations in the test objects. From a lift-off distance of 12mm, experiments were performed on eight SS304 stainless steel samples with thicknesses ranging from 1mm to 8mm. The SS304 steel was chosen as the test material to represent the steel type commonly used in the pipeline industry. A calibration curve based on the zero crossing time of initial measurements was obtained and implemented into the measurement software. Using the calibrated system, 25 measurements where performed on each sample. Statistical analysis of results showed that the proposed system can accurately detect thickness variations in the test samples with maximum measurement error of 3.3 percent.

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