Near electrical resonance signal enhancement (NERSE) in eddy-current crack detection

Hughes, Rhidian; Yang, Fan; Dixon, Steve

doi:10.1016/j.ndteint.2014.04.009

Cited by 49 publications

(14 citation statements)

References 20 publications

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“…A Zurich Instruments HFLI2 Lock-in Amplifier was used to operate and measure the electrical impedance of the ECT coil at 20 MHz. A Howland current source 1 was used to convert the input voltage into an equivalent current to the sensor coil [30], and mounted immediately behind the sensor coil to eliminate the detrimental high-frequency impedance effects of connecting cables. A low inductance, 25 turn, 1 mm external diameter coil was constructed in-house around a 0.75 mm diameter ferrite rod core 2 .…”

Section: Methodsmentioning

confidence: 99%

Characterisation of carbon fibre-reinforced polymer composites through radon-transform analysis of complex eddy-current data

Hughes

Drinkwater

Smith

2018

Composites Part B: Engineering

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Maintaining the correct fibre orientations and stacking sequence in carbon-fibre reinforced polymers (CFRP) during manufacture is essential for achieving the required mechanical properties of a component. This paper presents and evaluates a method for the rapid characterisation of the fibre orientations present in CFRP structures, and the differentiation of different stacking sequences, through the Radon-transform analysis of complex-valued eddy-current testing (ECT) inspection data. A high-frequency (20 MHz) eddy-current inspection system was used to obtain 2D scans of a range of CFRP samples of differing ply stacking sequences. The complex electrical impedance scan data was analysed using Radon-transform techniques to quickly and simply determine the dominant fibre orientations present in the structure. This method is compared to 2D-fast Fourier transform (2D-FFT) analysis of the same data and shown to give superior quantitative results with comparatively fewer computational steps and corrections. Further analysis is presented demonstrating and examining a method for preserving the complex information inherent within the eddycurrent scan data during Radon-transform analysis. This investigation shows that the real and imaginary components of the ECT data encode information about the sacking sequence allowing the distinction between composites with different stacking structures. This new analysis technique could be used for in-process analysis of CFRP structures as a more accurate characterisation method, reducing the chance of costly manufacturing errors.

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Section: Methodsmentioning

confidence: 99%

Characterisation of carbon fibre-reinforced polymer composites through radon-transform analysis of complex eddy-current data

Hughes

Drinkwater

Smith

2018

Composites Part B: Engineering

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“…For a non-ferromagnetic test material, this causes an upwards shift in the electrical resonance of the system. When the probe encounters a discontinuity, the effective inductance of the probe is altered and a downwards shift in the electrical resonant frequency occurs, giving rise to the NERSE effect documented in previous papers [4,3,5] and demonstrated in figure 2. The NERSE phenomenon can be exploited via operating at a single frequency within the NERSE band of a probe (on a given material) to improve signal-to-noise (SNR).…”

Section: Theorymentioning

confidence: 79%

“…Other factors cause changes in capacitance of the system, including, cable length/condition, soldering quality and more. The presence of phantom-resonance signals complicates the exploitation of NERSE phenomenon (see Hughes et al [4]) in array probes. The exploitation of the NERSE effect in an array would likely be much easier with all elements resonating at the same frequency, thereby eliminating the phantom resonance peaks.…”

Section: Discussionmentioning

confidence: 99%

“…In materials such as Titanium 6Al-4V (Ti6-4), adverse properties such as low electrical conductivity, σ, electrical anisotropy [1] and grain noise [2] increases the background material noise level limiting the sensitivity of the inspection to small defects. It has been shown previously [3,4,5] that behaviour of electrical resonance in the presence of material discontinuities enhances the signal-to-noise ratio (SNR) of defect signals within a region close to electrical resonance. The phenomenon has been dubbed near electrical resonance signal enhancement (NERSE) and arises due to changes in the effective reactance (X) of the EC probe shifting the resonant frequency to a lower value when encountering discontinuities.…”

Section: Introductionmentioning

confidence: 99%

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Investigating electrical resonance in eddy-current array probes

Hughes

Yang

Dixon

2016

AIP Conference Proceedings

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“…It should be noted that using probe operating at low frequency is limited to larger defect size and shape [7,8]. Besides making use of advanced signal/image processing techniques to improve the signal-to-noise ratio (SNR) for small cracks, there are techniques developed to further enhance the limitation in detection capability of conventional eddy current inspections such as pulsed eddy current (PEC) [9][10][11] and near electrical resonance signal enhancement (NERSE) [12,13]. In this technique, the eddy current probe is driven by current source sweeping through multiple frequencies close to its electrical resonance peak, where the response signals can be significantly boosted above the threshold of (electrical) background noise, thus enhance the resolution of the detected defect.…”

Section: Introductionmentioning

confidence: 99%

Modelling and Evaluation of Electrical Resonance Eddy Current for Submillimeter Defect Detection

Hor¹,

Sivaraja²,

Zhong³

et al. 2019

PIER C

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Eddy current (EC) inspection is used extensively in non-destructive testing (NDT) to detect surface-breaking defects of engineering components. However, the sensitivity of conventional eddy current inspection has plateaued in recent years. The ability to detect submillimetre defects before it becomes critical would allow engineering components to remain in-service safely for longer. Typically, it is required that higher frequency EC is employed to achieve a suitable sensitivity for detection of such submillimetre defects. However, that would lead to significant electromagnetic noise affecting the sensitivity of the inspection. To overcome this issue, the electrical-resonance based eddy current method has been proposed, where the electrical enhanced resonance signal increases the contrast between signal and noise, thus improving the sensitivity of the defect detection. This work aims to investigate the electrical-resonance system via simulation technology using combination of fast numerical-based simulation and circuit approach. Leveraging on this model, the detection system can be optimized by performing parameters tuning. Investigation of both experiment and simulation develops a precise calibration model for submillimeter defects detection.

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Near electrical resonance signal enhancement (NERSE) in eddy-current crack detection

Cited by 49 publications

References 20 publications

Characterisation of carbon fibre-reinforced polymer composites through radon-transform analysis of complex eddy-current data

Characterisation of carbon fibre-reinforced polymer composites through radon-transform analysis of complex eddy-current data

Investigating electrical resonance in eddy-current array probes

Modelling and Evaluation of Electrical Resonance Eddy Current for Submillimeter Defect Detection

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