Research on the defect types judgment in wind turbine blades using ultrasonic NDT

Li, Suwei; Shi, Kezhong; Yang, Kun; Xu, Jianzhong

doi:10.1088/1757-899x/87/1/012056

Cited by 12 publications

(10 citation statements)

References 1 publication

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“…Under the comprehensive effect of cyclic load due to wind, vibrations and other factors such as heat, acid and alkali, initial defects could be extended; in turn, the new defects such as fracture, holes, delamination or disbonding can be generated. Defects could also be generated due to random human error such as inadequacy of adhesive glue [ 26 ]. The scope of this paper is to explore the alternative approach for the defect analysis in WTB; thus, the simplified hole-type defect is considered in this research.…”

Section: Introductionmentioning

confidence: 99%

A Novel Defect Estimation Approach in Wind Turbine Blades Based on Phase Velocity Variation of Ultrasonic Guided Waves

Raišutis

Tiwari

Žukauskas

et al. 2021

Sensors

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The reliability of the wind turbine blade (WTB) evaluation using a new criterion is presented in the work. Variation of the ultrasonic guided waves (UGW) phase velocity is proposed to be used as a new criterion for defect detection. Based on an intermediate value between the maximum and minimum values, the calculation of the phase velocity threshold is used for defect detection, location and sizing. The operation of the proposed technique is verified using simulation and experimental studies. The artificially milled defect having a diameter of 81 mm on the segment of WTB is used for verification of the proposed technique. After the application of the proposed evaluation technique for analysis of the simulated B-scan image, the coordinates of defect edges have been estimated with relative errors of 3.7% and 3%, respectively. The size of the defect was estimated with a relative error of 2.7%. In the case of an experimentally measured B-scan image, the coordinates of defect edges have been estimated with relative errors of 12.5% and 3.9%, respectively. The size of the defect was estimated with a relative error of 10%. The comparative results obtained by modelling and experiment show the suitability of the proposed new criterion to be used for the defect detection tasks solving.

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Section: Introductionmentioning

confidence: 99%

A Novel Defect Estimation Approach in Wind Turbine Blades Based on Phase Velocity Variation of Ultrasonic Guided Waves

Raišutis

Tiwari

Žukauskas

et al. 2021

Sensors

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“…Strength is reduced because of 2 factors: The fibers are already in a buckled configuration (ie, a significant mode of compressive failure), and they are not aligned or disoriented . Inclusion defects are generated by the presence of foreign bodies within the composite layers . Voids are caused by air bubbles trapped in the laminate during the curing cycle or by nucleation from volatiles during processing .…”

Section: Introductionmentioning

confidence: 99%

Comparison of nondestructive testing techniques for the inspection of wind turbine blades' spar caps

Martin

Sabato

Schoenberg³

et al. 2018

Wind Energy

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To increase the energy conversion efficiency and power production, the size of wind turbine blades has continued to grow larger. As such, the need to identify defects and monitor the structural health becomes more critical to maintain reliability and prevent costly catastrophic failures. Larger blades are subject to an increased likelihood of operational damage and manufacturing defects. Usually, glass-reinforced spar caps are inspected with the assistance of strong flashlights, while nondestructive testing (NDT) inspections are performed only on carbon-reinforced blades which are not translucent. These operations provide qualitative information only. Therefore, there is a growing need for inspection techniques that can provide quantitative information for assessing the structural health of the blades. In recent years, different NDT techniques capable of accurately delivering surface and internal data have been developed. Nondestructive testing systems should be able to quickly and efficiently scan large areas, to be economically beneficial to the wind turbine manufacturing industry. Within this paper, 3 different NDT techniques for the inspection of manufactured wind turbine blades' spar caps are compared: terahertz inverse synthetic aperture radar, infrared thermography, and X-ray imaging. Each is investigated to evaluate their ability to detect the presence of defects of concern that are created during the blade manufacturing process. Through a set of experimental tests, the advantages, challenges, and drawbacks of each used technique are evaluated and compared in the context of the needs of the wind turbine industry. This research provides the foundation of empirical comparisons that can lead to the development of more accurate NDT resulting in the construction of more reliable and less-expensive wind turbine blades. KEYWORDS infrared thermography, nondestructive testing, terahertz inverse synthetic aperture radar, wind turbine blades, X-ray imaging

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“…The high-sensitivity, long-range inspection ability, high volumetric nature over the thickness of material are the main characteristics and therefore ultrasonic GW methods hold the upper position as compared to the other NDT methods for the estimation of defect size and location in the composite structures. [11][12][13] Although GW testing is an efficient NDT technique to estimate the defects in composite structures, the testing of WTB is still a challenging task and depends on the excitation frequency, sensitivity of transducers, environmental and system noise, properties of materials and so on [14][15][16] During the interaction of GW through the WTB, the phenomenon such as scattering of ultrasonic GW, refraction, reflection, attenuation and mode conversions may occur. Hence, the defect estimation by the signal parameters, that is, variation in amplitudes and frequencies, time of flight is not possible by just analyzing the experimental results.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Tiwari

Raišutis

2018

The Journal of Strain Analysis for Engineering Design

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In this work, the most promising ultrasonic signal processing methods-discrete wavelet transform, variational mode decomposition and Hilbert transform-are applied for the analysis of disbond-type defects in the segment of wind turbine blade. Two disbond-type artificial defects having diameters of 81 and 25 mm were located on the main spar of wind turbine blade. The low-frequency ultrasonic system developed by Ultrasound Research Institute of the Kaunas University of Technology was used for the experimental investigation of wind turbine blade using guided waves and only one side of the blade segment was accessed. Two contact type ultrasonic transducers separated by 50 mm distance and fixed on a movable mechanical panel were used as a transmitter-receiver pair during the experiment for the ultrasonic signals recording up to the scanning distance of 250 mm with the scanning step of 1 mm. Both types of defects were marginally detected from the conventional experimental B-scan and therefore appropriate signal processing techniques were used to improve the accuracy of the analysis of defects. The discrete wavelet transform was combined with the amplitude detection method for estimating the size and location of defects. Finally, the variational mode decomposition is combined with the Hilbert transform to compare the instantaneous frequencies and amplitudes of the defect-free and defective signals as well as for the measurement of time-delays between the defect-free and defective signals.

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Research on the defect types judgment in wind turbine blades using ultrasonic NDT

Cited by 12 publications

References 1 publication

A Novel Defect Estimation Approach in Wind Turbine Blades Based on Phase Velocity Variation of Ultrasonic Guided Waves

A Novel Defect Estimation Approach in Wind Turbine Blades Based on Phase Velocity Variation of Ultrasonic Guided Waves

Comparison of nondestructive testing techniques for the inspection of wind turbine blades' spar caps

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

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