Post-processing of ultrasonic signals for the analysis of defects in wind turbine blade using guided waves

Tiwari, Kumar Anubhav; Raišutis, Renaldas

doi:10.1177/0309324718772668

Cited by 20 publications

(9 citation statements)

References 45 publications

(55 reference statements)

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“…Either a signal processing or image processing approach can be applied to improve the accuracy in the measurement. Many signal processing techniques have been used for the refinement of experimental results by analyzing the amplitudes, phase velocity, instantaneous frequencies, or time of flight of the received signals [4,[28][29][30][31][32]. However, the consideration of the experimental results as an image requires an effective image processing technique to extract the defect features.…”

Section: Image Processing Techniquementioning

confidence: 99%

“…All the components, including the transducers and the LF ultrasonic system, was developed at the Ultrasound Research Institute of Kaunas University of Technology. The characteristics of the LF ultrasonic system are presented in Table 1 [31,32,37]. Before inspecting the sample for the analysis of defects, a linear scanning in the defect-free region was performed to estimate the dispersion curve.…”

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confidence: 99%

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Defect Estimation in Non-Destructive Testing of Composites by Ultrasonic Guided Waves and Image Processing

et al. 2019

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The estimation of the size and location of defects in multi-layered composite structures by ultrasonic non-destructive testing using guided waves has attracted the attention of researchers for the last few decades. Although extensive signal processing techniques are available, there are only a few studies available based on image processing of the ultrasonic B-scan image to extract the size and location of defects via the process of ultrasonic non-destructive testing. This work presents an image processing technique for ultrasonic B-scan images to improve the estimation of the location and size of disbond-type defects in glass fiber-reinforced plastic materials with 25-mm and 51-mm diameters. The sample is a segment of a wind turbine blade with a variable thickness ranging from 3 to 24 mm. The experiment is performed by using a low-frequency ultrasonic system and a pair of contact-type piezoceramic transducers kept apart by a 50-mm distance and embedded on a moving mechanical panel. The B-scan image acquired by the ultrasonic pitch-catch technique is denoised by utilizing features of two-dimensional discrete wavelet transform. Thereafter, the normalized pixel densities are compared along the scanned distance on the region of interest of the image, and a −3 dB threshold is applied to the locations and sizes the defects in the spatial domain.

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Section: Image Processing Techniquementioning

confidence: 99%

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confidence: 99%

Defect Estimation in Non-Destructive Testing of Composites by Ultrasonic Guided Waves and Image Processing

et al. 2019

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“…The contact type receiver was attached to the mechanical scanner which was connected to the low-frequency (LF) ultrasonic system developed by the Kaunas University of Technology, Kaunas, Lithuania. The parametric specifications of LF ultrasonic system are presented in Table 1 [ 32 , 58 , 59 ].…”

Section: Experimental Analysis Of Gfrp Samplementioning

confidence: 99%

Identification and Characterization of Defects in Glass Fiber Reinforced Plastic by Refining the Guided Lamb Waves

Tiwari

Raišutis

2018

Materials

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In this paper, the disbond-type defect presented on glass fiber reinforced plastic material is analyzed by refining the guided Lamb wave signals. A segment of wind turbine blade is considered as a test sample. The low-frequency ultrasonic measurement system is used for the non-destructive testing of the test sample using guided waves. The P-1 type macro-fiber composite transducer as a transmitter and contact-type piezoceramic transducer as a receiver are used for the testing of a sample. The disbond type defect having a diameter of 81 mm is detected from the experimental results. To improve the accuracy in locating and sizing the defects and estimation of the time of flight and phase velocity of ultrasonic guided waves in defective region, signal processing algorithm is developed by utilizing the promising properties of various ultrasonic signal processing techniques such as wavelet transform, amplitude detection, two-dimensional Fast-Fourier transform, Hilbert transform and variational mode decomposition. The discrete wavelet transform is used to denoise the guided wave signals and then, the size and location of defects are estimated by amplitude detection. The reflected wave signals from the opposite edge of the sample are removed by applying the two-dimensional Fast-Fourier transform to the experimental B-scan signal. Afterwards, variational mode decomposition and Hilbert transform are used for the phase velocity and time-delay estimation by comparing the instantaneous amplitudes of the defective and defect-free signal. The validation and the demonstration of reproducibility of the algorithm is performed by extracting the features of a 51 mm defect from another experimental B-scan.

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“…Ultrasonic inspection of sandwich panels is common (e.g., Refs. [10][11][12][13][14][15][16][17][18]), and a very basic American Society for Testing and Materials (ASTM) standard practice guide (ASTM E2580) for inspection of flat panels has been developed. Guided wave inspection appears to be particularly suitable for detecting disbonds in BVID, partly because of its ability to inspect large areas at once.…”

Section: Introductionmentioning

confidence: 99%

Eddy Current Array Inspection of Damaged CFRP Sandwich Panels

Underhill

Rellinger

Krause

et al. 2020

Journal of Nondestructive Evaluation, Diagnostics and Prognostics of Engineering Systems

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Abstract The use of eddy current (EC) arrays to detect damage in sandwich panels, such as disbonding of the carbon fiber reinforced polymer (CFRP) face-sheet to the core, is investigated. It is shown that the array is very sensitive to slight core crush and can readily find small dents and disbonds. At the same time, the eddy current array can look much deeper into the honeycomb to detect defects such as tears. The phase map of the EC signal can be used in some cases to distinguish between different types of damage. EC arrays offer the ability to rapidly scan large areas of CFRP panels.

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Post-processing of ultrasonic signals for the analysis of defects in wind turbine blade using guided waves

Cited by 20 publications

References 45 publications

Defect Estimation in Non-Destructive Testing of Composites by Ultrasonic Guided Waves and Image Processing

Defect Estimation in Non-Destructive Testing of Composites by Ultrasonic Guided Waves and Image Processing

Identification and Characterization of Defects in Glass Fiber Reinforced Plastic by Refining the Guided Lamb Waves

Eddy Current Array Inspection of Damaged CFRP Sandwich Panels

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