scholarly journals Frequency-sweep examination for wave mode identification in multimodal ultrasonic guided wave signal

2014 ◽  
Vol 61 (9) ◽  
pp. 1515-1524 ◽  
Author(s):  
Sina Fateri ◽  
Nikolaos V. Boulgouris ◽  
Adam Wilkinson ◽  
Wamadeva Balachandran ◽  
Tat-Hean Gan
Keyword(s):  
Wave Mode ◽  
Guided Wave ◽  
Frequency Sweep ◽  
Mode Identification ◽  
Wave Signal ◽  
Ultrasonic Guided Wave

Ultrasonic Guided-Wave Mode Identification in Pipe by Using Air-Coupled Transducer and Time-Frequency Analysis

2006 ◽  
Vol 321-323 ◽  
pp. 804-807 ◽  
Author(s):  
Ik Keun Park ◽  
Hyun Mook Kim ◽  
Yong Kwon Kim ◽  
Yong Sang Cho
Keyword(s):  
Guided Waves ◽  
Wave Mode ◽  
Guided Wave ◽  
Element Space ◽  
Mode Identification ◽  
Time Frequency ◽  
Dispersive Curve ◽  
Ultrasonic Guided Wave ◽  
Essential Components ◽  
2D Fft

For efficient NDE of pipes, essential components of power plant facilities, ultrasonic guided waves were generated and received applying an air-coupled transducer and comb one as non-contact technology. Mode generation and selection were predicted based on theoretical dispersive curve and the element space of a comb transducer. In addition, a receiving angle of the air-coupled transducer was determined to acquire the predicted modes by theoretical phase velocity of each mode. Theoretical dispersive curve was compared with the results of the time-frequency spectroscopes based on the wavelet transform and 2D-FFT to identify the characteristics of the received mode. The received modes show a good agreement with the predicted ones.

scholarly journals Phase-delayed laser diode array allows ultrasonic guided wave mode selection and tuning

2013 ◽  
Vol 113 (14) ◽  
pp. 144904 ◽  
Author(s):  
Pasi Karppinen ◽  
Ari Salmi ◽  
Petro Moilanen ◽  
Timo Karppinen ◽  
Zuomin Zhao ◽  
...  
Keyword(s):  
Laser Diode ◽  
Mode Selection ◽  
Wave Mode ◽  
Guided Wave ◽  
Diode Array ◽  
Laser Diode Array ◽  
Ultrasonic Guided Wave

scholarly journals Development of Ultrasonic Guided Wave Transducer for Monitoring of High Temperature Pipelines

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5443 ◽  
Author(s):  
Anurag Dhutti ◽  
Saiful Asmin Tumin ◽  
Wamadeva Balachandran ◽  
Jamil Kanfoud ◽  
Tat-Hean Gan
Keyword(s):  
High Temperature ◽  
Guided Waves ◽  
Elevated Temperatures ◽  
Element Model ◽  
Wave Mode ◽  
Guided Wave ◽  
Electromechanical Impedance ◽  
Active Sensor ◽  
Ultrasonic Guided Wave ◽  
Modes Of Vibration

High-temperature (HT) ultrasonic transducers are of increasing interest for structural health monitoring (SHM) of structures operating in harsh environments. This article focuses on the development of an HT piezoelectric wafer active sensor (HT-PWAS) for SHM of HT pipelines using ultrasonic guided waves. The PWAS was fabricated using Y-cut gallium phosphate (GaPO4) to produce a torsional guided wave mode on pipes operating at temperatures up to 600 °C. A number of confidence-building tests on the PWAS were carried out. HT electromechanical impedance (EMI) spectroscopy was performed to characterise piezoelectric properties at elevated temperatures and over long periods of time (>1000 h). Laser Doppler vibrometry (LDV) was used to verify the modes of vibration. A finite element model of GaPO4 PWAS was developed to model the electromechanical behaviour of the PWAS and the effect of increasing temperatures, and it was validated using EMI and LDV experimental data. This study demonstrates the application of GaPO4 for guided-wave SHM of pipelines and presents a model that can be used to evaluate different transducer designs for HT applications.

A Study on the Behavior of Ultrasonic Guided Wave Mode in a Pipe Using a Comb Transducer

2005 ◽  
Vol 297-300 ◽  
pp. 2182-2186
Author(s):  
Ik Keun Park ◽  
Yong Kwon Kim ◽  
Youn Ho Cho ◽  
Won Joon Song ◽  
Yeon Shik Ahn ◽  
...  
Keyword(s):  
Frequency Analysis ◽  
Mode Conversion ◽  
Group Velocity Dispersion ◽  
Longitudinal Mode ◽  
Wave Mode ◽  
Guided Wave ◽  
Flexural Mode ◽  
Time Frequency Analysis ◽  
Time Frequency ◽  
Ultrasonic Guided Wave

A preliminary study of the behavior of ultrasonic guided wave mode in a pipe using a comb transducer for maintenance inspection of power plant facilities has been verified experimentally. Guided wave mode identification is carried out in a pipe using time-frequency analysis methods such as wavelet transform (WT) and short time Fourier transform (STFT), compared with theoretically calculated group velocity dispersion curves for longitudinal and flexural mode. The results are in good agreement with analytical predictions and show the effectiveness of using the time-frequency analysis method to identify the individual guided wave modes. And, It was found out that longitudinal mode (0, 1) is affected by mode conversion less than the other modes. Therefore, L (0, 1) is selected as a optimal mode for evaluating location of the surface defect in a pipe.

scholarly journals Extraction of Least-Dispersive Ultrasonic Guided Wave Mode in Rail Track Based on Floquet-Bloch Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Maodan Yuan ◽  
Peter W. Tse ◽  
Weiming Xuan ◽  
Wenjin Xu
Keyword(s):  
Frequency Band ◽  
Complex Geometry ◽  
Numerical Study ◽  
Wave Mode ◽  
Guided Wave ◽  
Fe Model ◽  
Practical Applications ◽  
Rail Track ◽  
Ultrasonic Guided Wave ◽  
Full Cross Section

Ultrasonic guided wave (UGW) has shown great potential in the field of structural health monitoring of rail tracks due to its long-range capability and full cross section coverage. However, the practical application of UGW has been hindered by the complicated signal interpretation because of the natures of multiple modes and dispersion. Therefore, it is desirable that the effective UGW modes with high excitability and least dispersion can be identified and extracted for practical applications. In this paper, a numerical study on the guided wave propagation was carried out on a standard rail with 56E1 profile. Firstly, Floquet-Bloch theory was applied to obtain the dispersion curves of guided wave in a rail. Then, a 3D FE model was built to investigate the UGW propagation along the rail within the frequency range of 0–120 kHz. Wavenumber-frequency analysis method was applied to decompose and identify the propagating UGW modes. With a carefully designed 2D bandpass filter, a specific mode W0 was extracted in the wavenumber-frequency domain. Finally, a frequency band sweep technique was also proposed to get the optimal frequency band to achieve a pure and least-dispersive UGW mode along the rail web. The proposed method provides an effective way to extract efficient UGW modes to assess the integrity of the rail track, as well as other waveguides with complex geometry.

Design of Ultrasonic Guided Wave Excitation Signal Generator for Rotating Shafts

2012 ◽  
Vol 629 ◽  
pp. 570-575
Author(s):  
Xiao Yu Wang ◽  
Yan Yan Yang ◽  
Dao Shun Wang
Keyword(s):  
Surface Defects ◽  
Wave Mode ◽  
Guided Wave ◽  
Signal Generator ◽  
Wave Excitation ◽  
Rotating Shaft ◽  
Ultrasonic Guided Wave ◽  
Detection Technology ◽  
Test Component ◽  
Rotating Shafts

Ultrasonic guided wave detection technology has mangy special characteristics. It can spread very far along the components in the distance and it can throughout the whole thickness of components, so we can make use of ultrasonic guided wave to test component of internal and surface defects. The rotating shafts are the organizations widely used in the modern production but they are very easy to be dangerous faults. If we can realize the rotating shaft in time, it can reduce the danger. It is significant to design an affordable generator which produces signals to drive magnetostrictive probe that produces ultrasonic guided wave. In this paper, we choose the torsional wave as example to design signal generator. We will introduce the way to select the appropriate guided wave mode and frequency of excitation. Design signal generator with ATmega32, AD9851 and DAC0832.

Guided-wave signal processing by the sparse Bayesian learning approach employing Gabor pulse model

2016 ◽  
Vol 16 (3) ◽  
pp. 347-362 ◽  
Author(s):  
Biao Wu ◽  
Yong Huang ◽  
Xiang Chen ◽  
Sridhar Krishnaswamy ◽  
Hui Li
Keyword(s):  
Damage Detection ◽  
Bayesian Learning ◽  
Guided Waves ◽  
Learning Algorithm ◽  
Guided Wave ◽  
Sparse Bayesian Learning ◽  
Mode Identification ◽  
Wave Signal ◽  
Gabor Dictionary ◽  
The Many

Guided waves have been used for structural health monitoring to detect damage or defects in structures. However, guided wave signals often involve multiple modes and noise. Extracting meaningful damage information from the received guided wave signal becomes very challenging, especially when some of the modes overlap. The aim of this study is to develop an effective way to deal with noisy guided-wave signals for damage detection as well as for de-noising. To achieve this goal, a robust sparse Bayesian learning algorithm is adopted. One of the many merits of this technique is its good performance against noise. First, a Gabor dictionary is designed based on the information of the noisy signal. Each atom of this dictionary is a modulated Gaussian pulse. Then the robust sparse Bayesian learning technique is used to efficiently decompose the guided wave signal. After signal decomposition, a two-step matching scheme is proposed to extract meaningful waveforms for damage detection and localization. Results from numerical simulations and experiments on isotropic aluminum plate structures are presented to verify the effectiveness of the proposed approach in mode identification and signal de-noising for damage detection.

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