A review of the alternating current field measurement inspection technique

Raine, Alan; Lugg, Martin

doi:10.1108/02602289910279166

Cited by 31 publications

(20 citation statements)

References 1 publication

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“…Alternating Current Field Measurement (ACFM) is an electromagnetic inspection method capable of both detecting and sizing (length and depth) surface breaking cracks in metals [3]. The basis of the technique is that an alternating current can be induced to flow in a thin skin near the surface of any conductor.…”

Section: Introductionmentioning

confidence: 99%

Railroad inspection based on ACFM employing a non-uniform B-spline approach

Chacón

Márquez

Papaelias

2013

Mechanical Systems and Signal Processing

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a b s t r a c tThe stresses sustained by rails have increased in recent years due to the use of higher train speeds and heavier axle loads. For this reason surface and near-surface defects generate by Rolling Contact Fatigue (RCF) have become particularly significant as they can cause unexpected structural failure of the rail, resulting in severe derailments. The accident that took place in Hatfield, UK (2000), is an example of a derailment caused by the structural failure of a rail section due to RCF. Early detection of RCF rail defects is therefore of paramount importance to the rail industry. The performance of existing ultrasonic and magnetic flux leakage techniques in detecting rail surface-breaking defects, such as head checks and gauge corner cracking, is inadequate during high-speed inspection, while eddy current sensors suffer from lift-off effects. The results obtained through rail inspection experiments under simulated conditions using Alternating Current Field Measurement (ACFM) probes, suggest that this technique can be applied for the accurate and reliable detection of surface-breaking defects at high inspection speeds. This paper presents the BSpline approach used for the accurate filtering the noise of the raw ACFM signal obtained during high speed tests to improve the reliability of the measurements. A non-uniform Bspline approximation is employed to calculate the exact positions and the dimensions of the defects. This method generates a smooth approximation similar to the ACFM dataset points related to the rail surface-breaking defect.

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Section: Introductionmentioning

confidence: 99%

Railroad inspection based on ACFM employing a non-uniform B-spline approach

Chacón

Márquez

Papaelias

2013

Mechanical Systems and Signal Processing

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“…It has been proved as an effective tool for quantitative characterisation of hidden corrosion and cracks in multilayered aircraft structures [4,5], leading to the development of instruments for aircraft inspection [5][6][7][8][9]. For in-situ inspection for aerospace structures, various EC techniques are required, because each method has specific advantages, in multi-frequency excitation it is easy to classify defects at different depths [10], sensor arrays can inspect a large area [11] and alternating current field measurement (ACFM) can be used to evaluate defect depth [12]. Therefore, there is an increasing interest in developing an integrated portable EC instrument [13] with low cost and increased functionality.…”

Section: Introductionmentioning

confidence: 99%

Support vector machine and optimised feature extraction in integrated eddy current instrument

Pan

Luo

et al. 2013

Measurement

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“…Because of the paraffin deposit, the magnetic particle inspection (MPI) is inadequacy to detect the pipe string. ACFM is an electromagnetic technique capable of detecting and sizing (length and depth) defects in metallic components [3]. The ACFM probe induces a uniform current field into the surface of slab and the magnetic field will be changed when the current field is disrupted by the surface breaking crack [4][5][6][7], as shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

The detection of axial cracks in pipe string using a feed-through ACFM probe

Yuan

Chen

et al. 2014

2014 IEEE Far East Forum on Nondestructive Evaluation/Testing

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Pipe strings, as critical components in oil and gas industry, are highly susceptible to axial cracks for stress corrosion and fatigue damage. The conventional detection methods, such as magnetic flux leakage and magnetic particle inspection, are inadequate for accurately detecting a narrow axial crack. Alternating current field measurement (ACFM) technique is an electromagnetic inspection method capable of both detecting and sizing surface breaking cracks in metal specimens. This paper presents a novel feed-through ACFM probe used for axial cracks detection in pipe string. Both simulations and experiments are conducted to analyze the magnetic field disturbance above axial cracks and extract features for cracks recognition. The relationship between magnetic field features and the cracks is set up for quantitatively sizing cracks. The results show that the feed-through ACFM probe could make quantitative evaluation of axial cracks on the surface of pipe string.

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A review of the alternating current field measurement inspection technique

Cited by 31 publications

References 1 publication

Railroad inspection based on ACFM employing a non-uniform B-spline approach

Railroad inspection based on ACFM employing a non-uniform B-spline approach

Support vector machine and optimised feature extraction in integrated eddy current instrument

The detection of axial cracks in pipe string using a feed-through ACFM probe

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