The Measurement of Regular and Irregular Surface Cracks Using the Alternating Current Potential Difference Technique

2009 ◽  
pp. 3-3-14 ◽  
Author(s):  
MP Connolly
Keyword(s):  
Alternating Current ◽  
Potential Difference ◽  
Irregular Surface ◽  
Surface Cracks ◽  
Current Potential

scholarly journals Measuring the depth of surface cracks using alternating current potential drop technique, with suppression of the influence of the electromagnetic properties of the metal

2021 ◽  
Vol 2091 (1) ◽  
pp. 012047
Author(s):  
P N Shkatov
Keyword(s):  
Crack Depth ◽  
Potential Drop ◽  
Alternating Current ◽  
Measurement Range ◽  
Electromagnetic Properties ◽  
Surface Cracks ◽  
Measuring Techniques ◽  
Drop Technique ◽  
Current Potential

Abstract Traditional measuring techniques often lead to errors due to the need to register signals in both defective and defect-free areas. In this paper, we introduce an alternating current potential drop technique with detuning from the influence of variations in the electromagnetic properties of the metal achieved by registering a signal only at the defective site. We show that, with an appropriate choice of measurement parameters, the use of the proposed technique leads to an increase in sensitivity to the crack depth as well as to an increase in the measurement range.

Finite Element Analysis for the Evaluation of Cracks at a Pipe-Flange Welded Part by the Direct-Current Potential Difference Method

2015 ◽  
Author(s):  
Naoya Tada ◽  
Masaki Kosaka
Keyword(s):  
Finite Element ◽  
Direct Current ◽  
Difference Method ◽  
Evaluation Method ◽  
Fatigue Cracking ◽  
Potential Difference ◽  
Piping System ◽  
Element Analysis ◽  
Non Destructive ◽  
Current Potential

The use of a flange joint is a popular method to close the end of pipes or connect pipes in manufacturing industries. As the pipes are often subjected to vibrations and cyclic bending, fatigue cracking may occur at the welded part between the pipe and flange. It is therefore important to detect and monitor the cracking in this part to ensure safety of the whole piping system. The direct-current potential difference method (DC-PDM) is known as a suitable non-destructive technique to monitor the initiation and growth of cracks and it has been applied to cracks and wall thinning on the inner surface of pipes. In this study, finite element analyses were carried out to clarify the relationship between the size and location of cracks at the pipe-flange welded part and the potential difference. An evaluation method of circumferential crack length angle by DC-PDM was proposed.

ESTIMATION OF ERROR IN MEASURING THE DEPTH OF SURFACE CRACKS BY THE ELECTROPOTENTIAL METHOD ON AN ALTERNATING CURRENT

2020 ◽  
pp. 36-46
Author(s):  
P. N. Shkatov ◽  
I. G. Kuzub ◽  
A. A. Ermolaev
Keyword(s):  
Test Sample ◽  
Alternating Current ◽  
Electromagnetic Properties ◽  
Specific Electrical Conductivity ◽  
Measuring Error ◽  
Surface Cracks ◽  
Frequency Range ◽  
Estimation Of Error ◽  
The Difference ◽  
Free Area

The study carried out research on the error in measuring the depth of surface cracks by the electropotential method on an alternating current with a variation in the magnetic permeability and specific electrical conductivity of the metal. The measuring error appear from the difference between the electromagnetic properties of the metal of the sample used to obtain the calibration dependences and the properties of the metal of the tested object. The research conducted by the method of the finite element. The analysis of the dependences of the electropotential signal in the frequency range for the defect-free area and the area with a surface crack is carried out. The study of the error in measuring the depth h, that depends on the frequency of the transmitted current and the value of h. The comparison of the errors arising from various methods of choosing the calibration characteristics is performed, including the comparison of the equality of electropotential signals in the defect-free areas of the tested area and the test sample selected for calibration.

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