Crack Detection and Crack Length Measurement with the DC Potential Drop Method–Possibilities, Challenges and New Developments

The direct current potential drop method (DCPDM) is widely used to determine the crack length in fatigue experiments. In practice, some special features of this method must be considered. Aside from general information on the experimental setup and calibration, some special features of the method, such as the influence of the ambient atmosphere and the application of the method to ferromagnetic materials, are presented and discussed. In addition, with the multiple potential drop measurement, a method is presented which improves the resolution of the DCPDM for detection of cracks and allows to determine crack initiation sites. The capabilities provided by this method are demonstrated on the basis of measurements undertaken on notched round bars and single edged notched specimens.

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Effect of Initial Crack Length of C(T) Specimen on Crack Propagation Measurement by Dc Potential Drop Method

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/408/1/012011 ◽

2018 ◽

Vol 408 ◽

pp. 012011

Author(s):

Ni Chenqiang ◽

Xue He ◽

Wang Weibing

Keyword(s):

Crack Propagation ◽

Crack Length ◽

Potential Drop ◽

Initial Crack ◽

Initial Crack Length ◽

Drop Method ◽

Dc Potential ◽

Propagation Measurement

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The Effect of Large Scale Plastic Deformation on Fatigue Crack Length Measurement with the Potential Drop Method

Journal of Testing and Evaluation ◽

10.1520/jte103532 ◽

2011 ◽

Vol 39 (6) ◽

pp. 103532 ◽

Cited By ~ 2

Author(s):

M. R. Mitchell ◽

R. E. Link ◽

P. Ljustell

Keyword(s):

Plastic Deformation ◽

Fatigue Crack ◽

Crack Length ◽

Large Scale ◽

Potential Drop ◽

Length Measurement ◽

Drop Method ◽

Crack Length Measurement

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Electrical Potential Drop and Notch Opening Displacement Methods for Detecting High Temperature Low Cycle Fatigue Cracks of Circumferential Notched Specimens

Journal of Engineering Materials and Technology ◽

10.1115/1.3226044 ◽

1988 ◽

Vol 110 (3) ◽

pp. 247-252 ◽

Cited By ~ 10

Author(s):

Masao Sakane ◽

Masateru Ohnami

Keyword(s):

Maximum Stress ◽

Low Cycle Fatigue ◽

Potential Drop ◽

Cycle Fatigue ◽

Displacement Method ◽

Opening Displacement ◽

Stress Criterion ◽

Drop Method ◽

Notched Specimens ◽

Dc Potential

This paper assesses the accuracy of the crack initiation detection methods for type 304 SS circumferential notched specimens subjected to strain and stress controlled low cycle fatigue loads at 873 K in air. The methods examined were DC potential drop method (PDM) and the maximum stress criterion in the strain controlled test while they were DC potential drop method and the minimum notch opening displacement method (NOD) in the stress controlled test. The DC potential method and the minimum notch opening displacement method were proved to have a sufficient accuracy for the detection of crack initiation while the maximum stress criterion has less accuracy. The crack length detection based on DC potential drop method is also discussed.

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