Identification of multiple damage using modal rotation obtained with shearography and undecimated wavelet transform

Katunin, Andrzej; Lopes, H.; Santos, J.V. Araújo dos

doi:10.1016/j.ymssp.2018.07.024

Cited by 32 publications

(18 citation statements)

References 21 publications

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“…This phase map contains noise, and thus filtering is necessary. In the present study, the sine/cosine average filter was applied, which shows effectiveness in filtering proven in the previous studies [6,15]. Afterwards, the resulting filtered phase map was subjected to unwrapping procedure following the Goldstein unwrapping algorithm.…”

Section: Shearography and Damage Casesmentioning

confidence: 83%

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Efficiency assessment of wavelet transforms and wavelets for damage localization in beams using shearography

et al. 2018

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Non-destructive testing of engineering structures and elements in operation is one of the crucial steps in recently introduced design philosophies: damage tolerance and condition-based maintenance. Therefore, it is important to provide effective non-destructive testing methods, which are able to detect and identify a possible damage in early stage of its development. One effective testing method, which still gains its popularity in various industrial applications, is shearography. Although, shearography is sensitive to various types of structural damage and flaws, this sensitivity can be significantly improved by applying advanced post-processing algorithms to raw data obtained from measurements. An excellent candidate for such an improvement is the wavelet analysis, due to its very high sensitivity to smallest signal disturbances. This study presents results of comparative analysis of various wavelet transforms and various wavelets in order to analyse their sensitivity to damage. The improvement in damage detectability is verified using experimental data.

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Section: Shearography and Damage Casesmentioning

confidence: 83%

“…One of those tools is wavelet analysis (WA), which has been already used as a diagnostic supporting tool for the enhancement of NDT methods [14]. Its ability to identify singularities and discontinuities in the analysed signal makes it promising for damage identification problems, which was already proven in a previous study [15].…”

Section: Introductionmentioning

confidence: 99%

Efficiency assessment of wavelet transforms and wavelets for damage localization in beams using shearography

et al. 2018

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“…Structural damage identification, aiming at detecting and assessing the structural damage at or near its onset during operation, plays a significant role in maintaining the safety and reliability of civil and mechanical structures [ 1 , 2 , 3 ]. One of the major challenges in this field is that damage is a local phenomenon that naturally appears and propagates in a small region, which presents a great difficulty in detection [ 4 , 5 , 6 ]. Therefore, an effective damage identification approach should be local in nature [ 7 , 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

Robust Baseline-Free Damage Localization by Using Locally Perturbed Dynamic Equilibrium and Data Fusion Technique

Cao

Ouyang

2020

Sensors

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Mode shape-based structural damage identification methods have been widely investigated due to their good performances in damage localization. Nevertheless, the evaluation of mode shapes is severely affected by the measurement noise. Moreover, the conventional mode shape-based damage localization methods are normally proposed based on a certain mode and not effective for multi-damage localization. To tackle these problems, a novel damage localization approach is proposed based on locally perturbed dynamic equilibrium and data fusion approach. The main contributions cover three aspects. Firstly, a joint singular value decomposition technique is proposed to simultaneously decompose several power spectral density transmissibility matrices for robust mode shape estimation, which statistically deals better with the measurement noise than the traditional transmissibility-based methods. Secondly, with the identified mode shapes, an improved pseudo-excitation method is proposed to construct a baseline-free damage localization index by quantifying the locally damage perturbed dynamic equilibrium without the knowledge of material/structural properties. Thirdly, to circumvent the conflicting damage information in different modes and integrate it for robust damage localization, a data fusion scheme is developed, which performs better than the Bayesian fusion approach. Both numerical and experimental studies of cantilever beams with two cracks were conducted to validate the feasibility and effectiveness of the proposed damage localization method. It was found that the proposed method outperforms the traditional transmissibility-based methods in terms of localization accuracy and robustness.

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“…For crack localization, it is necessary to have enough spatial information. Crack localization by modal parameters, such as natural frequencies and mode shapes or their derivatives, has been widely investigated in structures [ 25 , 26 , 27 , 28 ]. As the natural frequencies are global parameters, reference models are required to provide more spatial information for the natural frequency-based methods.…”

Section: Introductionmentioning

confidence: 99%

Baseline-Free Adaptive Crack Localization for Operating Stepped Rotors Based on Multiscale Data Fusion

Cao

Yuan

et al. 2020

Sensors

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Crack localization in running rotors is very important and full of challenges for machinery operation and maintenance. Characteristic deflection shapes or their derivatives based methods seem to be promising for crack localization in rotors. Despite the substantial advantages, several critical issues still need to be addressed to enhance the efficiency of this kind of method for practical applications. Two problems are considered in this work: 1. How to localize single or multiple cracks accurately avoiding the interference of commonly existing steps without baseline information on pristine rotors; 2. How to improve the crack localization performance under a noisy environment. To circumvent the issues, a novel baseline-free adaptive crack localization method is proposed based on data fusion of multiscale super-harmonic characteristic deflection shapes (SCDSs). In this method, crack induced asymmetry and nonlinearity of crack breathing are utilized to simultaneously eliminate the interference from the steps without a reference model. To enhance the noise robustness, the multiscale representations of SCDSs are made in Gaussian multiscale space, and Teager energy operator is applied to the multiscale SCDSs to amplify the crack induced singularities and construct the multiscale Teager super-harmonic characteristic deflection shapes (TSCDSs). Moreover, fractal dimension is designed as an evaluator to select the proper multiscale TSCDSs for data fusion adaptively. Then, a new damage index is derived for crack localization by Dempster-Shafer’s (D-S) evidence fusion of the adaptively selected multiscale TSCDSs. Finally, the feasibility and the effectiveness are verified by both numerical and experimental investigations.

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Identification of multiple damage using modal rotation obtained with shearography and undecimated wavelet transform

Cited by 32 publications

References 21 publications

Efficiency assessment of wavelet transforms and wavelets for damage localization in beams using shearography

Efficiency assessment of wavelet transforms and wavelets for damage localization in beams using shearography

Robust Baseline-Free Damage Localization by Using Locally Perturbed Dynamic Equilibrium and Data Fusion Technique

Baseline-Free Adaptive Crack Localization for Operating Stepped Rotors Based on Multiscale Data Fusion

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