Damage Localization in Plates Using Mode Conversion Characteristics of Ultrasonic Guided Waves

Hosseini, Seyed Mohammad Hossein; Duczek, Sascha; Gabbert, Ulrich

doi:10.1007/s10921-013-0211-y

Cited by 11 publications

(9 citation statements)

References 33 publications

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“…For more information the reader is referred to the literature reviews (19), (20). A considerable number of researchers have used several approaches for the effective use of Lamb waves for damage detection purposes, such as modelling and numerical analysis (12), physics-based (21) and signal processing-based (22) techniques. Among the most notable works performed on composite repaired structures; the first anti-symmetric Lamb wave mode was generated at low frequencies in sandwiches and composite single and double-lap repairs in order to detect impact damage (23).…”

Section: Lamb Wavesmentioning

confidence: 99%

“…In recent years, researchers have become increasingly interested in the problems related to repair patches that can emerge either from design issues or from extensive loading, such as the risk of debonding between the patch and the substrate when the ultimate shear strength of the adhesive is exceeded (9). A number of studies have investigated these phenomena (10), (11), (12). Clearly, a reliable in service monitoring of the performance is a very critical step towards the certification of the technique by the Civil Aviation Authorities, especially of primary load carrying structures (2), (13).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Continuous debonding monitoring of a patch repaired helicopter stabilizer: Damage assessment and analysis

Pavlopoulou

Grammatikos

Kordatos

et al. 2015

Composite Structures

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The present work focuses on the structural health monitoring of an aluminium vertical helicopter stabiliser with a pre-introduced crack which was repaired with an adhesively bonded composite patch. The structure was monitored under bending fatigue and its performance was evaluated with Lamb waves, lock-in thermography and ultrasonic testing. Outlier analysis of Lamb waves captured the onset and progress of the damage in the form of patch debonding, enabling the identification of five damage-severity regions. Principal component analysis showed distinctive clusters that corresponded to different damage levels while the application of principal curves on the selected features proved to be an additional damage detection index. Amplitude and phase lock-in images accurately captured the onset and evolution of the damage in the form of patch debonding and honeycomb/skin debonding in agreement with the damage indices obtained from Lamb waves. C-scan further validated the damage mechanisms that were captured by the other methods.

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Section: Lamb Wavesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Continuous debonding monitoring of a patch repaired helicopter stabilizer: Damage assessment and analysis

Pavlopoulou

Grammatikos

Kordatos

et al. 2015

Composite Structures

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“…This topic was investigated by authors of work [2] where the effect of continuous mode conversion in CFRP plate were analyzed. In the paper [3] mode conversion phenomenon and continuous wavelet transform were utilized for damage localisation in sandwich structures. Authors of paper [4] utilized mode conversion phenomenon for estimation of rectangular notch parameters in the metallic plate.…”

Section: Introductionmentioning

confidence: 99%

Analysis of S0/A0 elastic wave mode conversion phenomenon in glass fibre reinforced polymers

2018

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In this paper results of experimental analysis of elastic guided wave mode conversion phenomenon in glass fibre reinforced polymers GFRP are presented. Results of research presented in this paper are strictly focused on S0/A0' mode conversion caused by discontinuities in the form of circular teflon insert simulating damage and impact damage. Experimental research is based on non-contact elastic wave sensing with utilisation of scanning laser Doppler vibrometer SLDV and full wave-field measurements. In presented research influence of location of circular teflon insert on S0/A0' mode conversion is investigated. Teflon inserts were located between layers of composite material at different depth. Moreover influence of impact damage with different energy on S0/A0' mode conversion is investigated. Analysis of influence of investigated discontinuities on S0/A0' mode conversion are based on the elastic wave mode filtration in frequency-wavenumber domain. Mode filtration process allows to remove effects of unwanted type of mode propagation in forward or backward direction. Effects of S0/A0' mode conversion are characterise by mode conversion indicator based on amplitude of new mode A0'.

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“…Wavelet denoising using either DWT or SWT is a well established and efficient method for ultrasonic signal denoising. In particular, wavelet techniques have been used for noise reduction and flaw detection in different NDE ultrasonic applications [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. It is considered as a non-parametric method, since any particular model is assumed and therefore any parameter must be estimated.…”

Section: Introductionmentioning

confidence: 99%

Wavelet Cycle Spinning Denoising of NDE Ultrasonic Signals Using a Random Selection of Shifts

Emeterio

Rodríguez-Hernández

2014

J Nondestruct Eval

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Wavelets are a powerful tool for signal and image denoising. Most of the denoising applications in different fields were based on the thresholding of the discrete wavelet transform (DWT) coefficients. Nevertheless, DWT transform is not a time or shift invariant transform and results depend on the selected shift. Improvements on the denoising performance can be obtained using the stationary wavelet transform (SWT) (also called shift-invariant or undecimated wavelet transform). Denoising using SWT has previously shown a robust and usually better performance than denoising using DWT but with a higher computational cost. In this paper, wavelet shrinkage schemes are applied for reducing noise in synthetic and experimental non-destructive evaluation (NDE) ultrasonic A-scans, using DWT and a cycle-spinning implementation of SWT.A new denoising procedure, which we call Random Partial Cycle Spinning (RPCS), is presented. It is based on a cycle-spinning over a limited number of shifts that are selected in a random way. Wavelet denoising based on DWT, SWT and RPCS have been applied to the same sets of ultrasonic A-scans and their performances in terms of SNR are compared. In all cases three well known threshold selection rules (Universal, Minimax and Sure), with decomposition level dependent selection, have been used. It is shown that the new procedure provides a good robust denoising performance, without the DWT fluctuating performance, and close to SWT but with a much lower computational cost.

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Damage Localization in Plates Using Mode Conversion Characteristics of Ultrasonic Guided Waves

Cited by 11 publications

References 33 publications

Continuous debonding monitoring of a patch repaired helicopter stabilizer: Damage assessment and analysis

Continuous debonding monitoring of a patch repaired helicopter stabilizer: Damage assessment and analysis

Analysis of S0/A0 elastic wave mode conversion phenomenon in glass fibre reinforced polymers

Wavelet Cycle Spinning Denoising of NDE Ultrasonic Signals Using a Random Selection of Shifts

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