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

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4879
Author(s):  
Renaldas Raišutis ◽  
Kumar Anubhav Tiwari ◽  
Egidijus Žukauskas ◽  
Olgirdas Tumšys ◽  
Lina Draudvilienė
Keyword(s):  
Phase Velocity ◽  
Wind Turbine ◽  
Relative Error ◽  
Defect Detection ◽  
Guided Waves ◽  
Experimental Studies ◽  
Ultrasonic Guided Waves ◽  
Velocity Variation ◽  
Relative Errors ◽  
New Criterion

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.

Phase velocity estimation technique based on adaptive beamforming for ultrasonic guided waves propagating along cortical long bones

2017 ◽  
Vol 56 (7S1) ◽  
pp. 07JF06 ◽  
Author(s):  
Shigeaki Okumura ◽  
Vu-Hieu Nguyen ◽  
Hirofumi Taki ◽  
Guillaume Haïat ◽  
Salah Naili ◽  
...  
Keyword(s):  
Phase Velocity ◽  
Guided Waves ◽  
Adaptive Beamforming ◽  
Velocity Estimation ◽  
Ultrasonic Guided Waves ◽  
Long Bones ◽  
Estimation Technique

scholarly journals The Effects of Stress on Second Harmonics in Plate-Like Structures

2020 ◽  
Vol 10 (15) ◽  
pp. 5124
Author(s):  
Xiaochuan Niu ◽  
Liqiang Zhu ◽  
Zujun Yu
Keyword(s):  
Guided Waves ◽  
Second Harmonic ◽  
Experimental Studies ◽  
Arbitrary Cross Section ◽  
Ultrasonic Guided Waves ◽  
Analysis Method ◽  
Harmonic Mode ◽  
Amplitude Coefficient ◽  
Theoretical Predictions ◽  
Application Potential

Cumulative second harmonic of ultrasonic guided waves is considered to have great application potential in evaluating internal stress of structures. One difficulty with the application is the diversity and complexity of modal response to the stress change in waveguide. At present, there is a lack of relevant theoretical studies and experimental results to guide the applications. In this article, a method is proposed to characterize the amplitude change of cumulative second harmonic mode in a plate under stress through calculating the amplitude coefficient, which can be acquired based on mode shape analysis. The steel plate is taken as an example to demonstrate the analysis method. Experimental studies are presented with results consistent with the theoretical predictions. The results of this study indicate that the amplitudes of different cumulative second harmonic modes may increase or decrease monotonically with the change of stress. Therefore, when the phenomenon of modes mixing occurs in the waveguide, it is necessary to analyze and predict the amplitude of selected cumulative second harmonic mode with the change of stress in advance; otherwise, wrong results may be obtained. The method and conclusions proposed in this paper can also be applicable to waveguide of arbitrary cross-section and have universality.

scholarly journals Shear-Actuation and Vibrometer Reception of Penetrating Ultrasonic Guided Wave Modes in Human Tibia

2020 ◽  
Vol 10 (23) ◽  
pp. 8397
Author(s):  
Anurup Guha ◽  
Michael Aynardi ◽  
Parisa Shokouhi ◽  
Cliff J. Lissenden
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Phase Velocity ◽  
Time Domain ◽  
Guided Waves ◽  
Ultrasonic Guided Waves ◽  
Appendicular Skeleton ◽  
Element Analysis ◽  
Human Tibia ◽  
Wave Modes

The hollow long bones of the human appendicular skeleton are known to support the propagation of ultrasonic guided waves, whose potential for diagnosing bone health is being investigated. In this study, ultrasonic guided waves propagating in the diaphysis of human tibia are characterized experimentally and numerically in the frequency range around 200 kHz. The experiment involves a unique combination of omni-directional shear transducer-based excitation and detection using a 1D laser Doppler vibrometer. The cluster of phase velocities obtained from a linear array of time-history data using space-time Fourier transform is found to be in the non-dispersive low-phase velocity region of the dispersion curves obtained for a tibial cross-section. Time-domain finite element analysis revealed that the displacement components normal to the surface are significant, even though the loading is from a shear transducer. Furthermore, semi-analytical finite element analysis revealed that the wave structures of the wave modes contained within the cluster of low-phase velocity modes are consistent with the displacement profiles obtained from the time-domain analysis. The experimental results show that the low-phase velocity mode cluster has sufficient intensity to propagate axially at least 85 mm in the mid-diaphyseal region.

scholarly journals Excitation and Propagation of Longitudinal L (0, 2) Mode Ultrasonic Guided Waves for the Detection of Damages in Hexagonal Pipes: Numerical and Experimental Studies

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Xiang Wan ◽  
Meiru Liu ◽  
Xuhui Zhang ◽  
Hongwei Fan ◽  
Qinghua Mao ◽  
...  
Keyword(s):  
Guided Waves ◽  
Experimental Studies ◽  
Special Kind ◽  
Dispersion Curves ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Resource Exploitation ◽  
Ultrasonic Guided Wave ◽  
Study Results ◽  
Through Hole

The hexagonal pipe is a special kind of tube structure. Its inner surface of the cross section is in the shape of circle, while the outer surface is hexagonal. It has functioned as an essential and critical part of a drill stem in a high-torque drill machine used in various resource exploitation fields. The inspection of a hexagonal pipe to avoid its failure and thus to ensure safe operation of a drilling machine is becoming increasingly urgent and important. In this study, the excitation and propagation of ultrasonic guided waves for the purpose of detecting defects in hexagonal pipes are proposed. Dispersion curves of hexagonal pipes are firstly derived by using semianalytical finite element method. Based on these dispersion curves, longitudinal L (0, 2) mode at 100 kHz is selected to inspect hexagonal pipes. A ring of piezoelectric transducers (PZTs) with the size of 25 mm × 5 mm ×0.5 mm is able to maximize the amplitude of L (0, 2) mode and successfully suppress the undesired L (0, 1) mode in the experiments. Numerical and experimental studies have shown that the displacement field of L (0, 2) mode at 100 kHz is almost uniformly distributed along the circumferential direction. Furthermore, L (0, 2) mode ultrasonic guided waves at 100 kHz are capable of detecting circular through-hole damages located in the plane and near the edge in a hexagonal pipe. Our study results have demonstrated that the use of longitudinal L (0, 2) mode ultrasonic guided wave provides a promising and effective alternative for the detection of defects in hexagonal pipe structures.

scholarly journals Simulation Research on Defect Detection in Station Process Pipelines using Ultrasonic Guided Waves

2021 ◽  
Vol 2033 (1) ◽  
pp. 012208
Author(s):  
Yi Jiang ◽  
YuTing Liu ◽  
LeiChao Wang ◽  
Feng Li ◽  
Ge Chen ◽  
...  
Keyword(s):  
Defect Detection ◽  
Guided Waves ◽  
Ultrasonic Guided Waves ◽  
Simulation Research

DELAMINATION DEFECT DETECTION USING ULTRASONIC GUIDED WAVES IN ADVANCED HYBRID STRUCTURAL ELEMENTS

2010 ◽  
Author(s):  
Fei Yan ◽  
Kevin “Xue” Qi ◽  
Joseph L. Rose ◽  
Hasso Weiland ◽  
Donald O. Thompson ◽  
...  
Keyword(s):  
Defect Detection ◽  
Guided Waves ◽  
Ultrasonic Guided Waves ◽  
Structural Elements
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