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Total Focusing Method Damage Imaging in Frequency Domain Using Laser-Ultrasonic lamb wave Based on Time-domain Filtering in Multi-band

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Acta Mechanica Solida Sinica 2021年第3期34卷 404-424页

作者： Fengzhong Li Ying Luo National Center for International Research on Structural Health Management of Critical Components Jiangsu UniversityZhenjiang 212013China

A fully non-contact experimental platform for ultrasonic lamb wave damage detection was constructed,where laser exciting and the scanning laser Doppler vibrometer were used to realize the high-resolution pickup of the lamb wave field in the structure,which has overcome the disadvantages of low spatial resolution caused by the conventional contact lamb wave *** order to suppress the dispersion effect of broadband laser-ultrasonic signal,we proposed time-domain filtering in multi-band method based on wavelet analysis to decompose the broadband signal into multiple narrowband ones and separate the scattering signals effectively without reference *** this basis,the total focusing method(TFM)was used for damage ***,when the traditional TFM was applied to image based on ultrasonic lamb wave,the inherent dispersion characteristic of ultrasonic lamb wave could lead to the miscalculation of time delay,thus reducing the imaging ***,the frequency-domain TFM was developed by applying phase delay in the frequency *** logical AND was introduced to synthesize the damage imaging results of multiple narrowband signals to obtain high-precision damage *** study has shown that the method of time-domain filtering in multi-band combining with frequency-domain TFM can realize non-contact and accurate damage detection in isotropic plate structures,and it is a potential effective method for application in engineering practice.

关键词： Laser ultrasound lamb wave Multi-band wavelet analysis Dispersion Total focusing method

A lamb wave quantification model for inclined cracks with experimental validation

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Chinese Journal of Aeronautics 2021年第2期34卷 601-611页

作者： Jingjing HE Haode HUO Xuefei GUAN Jinsong YANG School of Reliability and Systems Engineering Beihang UniversityBeijing 100083China Graduate School of China Academy of Engineering Physics Beijing 100193China CAD/CAM Institute Central South UniversityChangsha 410083China

This paper investigates the influence of crack orientation on damage quantification using lamb wave in plate structures. Finite element simulation is performed to acquire lamb wave signal responses for different configurations of crack orientations and crack lengths. Two lamb wave features, namely the normalized amplitude and the phase change, are used as damage sensitive features to develop a crack size quantification model. A hypothesis based on the geometrical influence on signal features is proposed, and the crack size quantification model incorporating the orientation angle is established using the hypothesis. An index of Probability of Reliable Quantification(PRQ) is proposed to evaluate the performance of the model. The index can be used to determine the sizing risk in terms of probabilities. A realistic aluminum plate is used to obtain the experimental data using piezoelectric(PZT) wafer-type sensors around a center through crack. The experimental data are used to validate the overall method. Results indicate that the proposed model can yield reliable results for size quantification of inclined cracks.

关键词： Crack orientation Crack size quantification model Incident angle lamb wave Probability of reliable quantification(PRQ)

Design and fabrication of a MEMS lamb wave device based on ZnO thin film

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Journal of Semiconductors 2011年第4期32卷 77-82页

作者：刘梦伟李俊红马军汪承灏 Institute of Acoustics Chinese Academy of Sciences

This paper presents the design and fabrication of a lamb wave device based on ZnO piezoelectric film. The lamb waves were respectively launched and received by both Al interdigital *** order to reduce the stress of the thin membrane,the ZnO/Al/LTO/Si;N;/Si multilayered thin plate was designed and fabricated.A novel method to obtain the piezoelectric constant of the ZnO film was *** experimental results for characterizing the wave propagation modes and their frequencies of the lamb wave device indicated that the measured center frequency of antisymmetric A;and symmetric S;modes lamb wave agree with the theoretical *** mass sensitivity of the MEMS lamb wave device was also characterized for gravimetric sensing application.

关键词： lamb wave MEMS ZnO film composite plate

Non-contact air-coupled transducers lamb wave signal multipath effect and blind separation for different modes using PZT as receiver

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Chinese Journal of Aeronautics 2024年第10期37卷 424-434页

作者： Desheng WU Zhibo YANG Yu RUAN Wenbo LI Lijuan YANG Xuefeng CHEN National Key Lab of Aerospace Power System and Plasma Technology Xi’an Jiaotong UniversityXi’an 710049China School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China

Due to the complexity and faintness of the detection wave patterns obtained by aircoupled transducers,if it is possible to effectively separate the various modes and obtain nondispersive signals for more accurate detection and positioning,it will help to improve the accuracy and reliability of air-coupled ultrasonic lamb wave detection,providing better technical support for the application and development of related *** of the increased complexity of aircoupled signals,there is no definite theoretical formula to describe the mode changes of aircoupled signals,so the method based on blind separation has unique *** address these challenges,the paper proposes a single-channel blind source separation(SCBSS)*** effectiveness of this method is evaluated through simulations and experiments,demonstrating favorable separation results and efficient computational *** work first conducts an in-depth analysis of the signal characteristics of air-coupled ultrasonic non-destructive testing,and simulates the ultrasonic excitation conditions of air-coupled sensors through finite element *** study of modal changes and multipath effects caused by the variation of the incidence angle of the ACT signal is carried out,and the situation of the lamb wave signal excited by ACT at the receiving end is *** combining ACT with PZT signals,the ultrasonic signals of air-coupled lamb waves are compared and studied,and their modal purification is carried out.

关键词： Air-coupled transducers lamb wave Mode separation Blind source separation Non-destructive testing

Time-domain analysis of second-harmonic generation of primary lamb wave propagation in an elastic plate

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Chinese Physics B 2010年第11期19卷 456-464页

作者：邓明晰项延训 Department of Physics Logistics Engineering University School of Mechanical and Power Engineering East China University of Science and Technology

Within the second-order perturbation approximation, this paper investigates the physical process of generation of the time-domain second harmonic by a primary lamb wave waveform in an elastic plate. The present work is performed based on the preconditions that the phase velocity matching is satisfied and that the transfer of energy from the primary lamb wave to the double frequency lamb wave is not zero. It investigates the influences of the difference between the group velocities of the primary lamb wave and the double frequency lamb wave, the propagation distance and the duration of the primary lamb wave waveform on the envelope shape of the time-domain second harmonic. It finds that the maximum magnitude of the envelope of the second-harmonic waveform can grow within some propagation distance even if the condition of group velocity matching is not satisfied. Our analyses also indicate that the maximum magnitude of the envelope of the second-harmonic waveform is kept constant beyond a specific propagation distance. Furthermore, it concludes that the integration amplitude of the time-domain second-harmonic waveform always grows with propagation distance within the second-order perturbation. The present research yields new physical insight not previously available into the effect of generation of the time-domain second harmonic by propagation of a primary lamb wave waveform.

关键词： lamb wave second-harmonic generation group velocity matching phase velocity matching

Application of Nonlinear lamb wave Mixing Method for Residual Stress Measurement in Metal Plate

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Chinese Journal of Mechanical Engineering 2023年第1期36卷 211-223页

作者： Jingpin Jiao Li Li Xiang Gao Quan Cheng Cunfu He Bin Wu Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing 100124China

Harmonic nonlinear ultrasound can offer high sensitivity for residual stress measurements;however,it cannot be used for local stress measurements at a point in space and exhibits nonlinear distortions in the experimental *** paper presents a feasibility study on the measurement of residual stress in a metal plate using a nonlinear lamb wave-mixing *** resonant conditions for two lamb waves to generate a mixing frequency wave are obtained via theoretical *** element simulations are performed to investigate the nonlinear interactions between the two lamb *** show that two incident A0 waves interact in regions of material nonlinearity and generate a rightward S0 wave at the sum *** stress measurement experiments are conducted on steel plate specimens using the collinear lamb wave-mixing *** setting different delays for two transmitters,the generated sum-frequency component at different spatial locations is *** results show that the spatial distribution of the amplitude of the sum-frequency component agrees well with the spatial distribution of the residual stress measured using *** proposed collinear lamb wave-mixing method is effective for measuring the distribution of residual stress in metal plates.

关键词： Residual stress lamb wave Collinear wave mixing Nondestructive testing Resonant conditions

Aluminum Alloy Fatigue Crack Damage Prediction Based on lamb wave-Systematic Resampling Particle Filter Method

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Structural Durability & Health Monitoring 2022年第1期16卷 81-96页

作者： Gaozheng Zhao Changchao Liu Lingyu Sun Ning Yang Lei Zhang Mingshun Jiang Lei Jia Qingmei Sui College of Control Science and Engineering Shandong UniversityJinan250061China Shandong Institute of Space Electronic Technology Yantai264010China

Fatigue crack prediction is a critical aspect of prognostics and health management *** particle filter algorithm based on lamb wave is a potential tool to solve the nonlinear and non-Gaussian problems on fatigue growth,and it is widely used to predict the state of fatigue *** paper proposes a method of lamb wavebased early fatigue microcrack prediction with the aid of particle *** this method,which the changes in signal characteristics under different fatigue crack lengths are analyzed,and the state-and observation-equations of crack extension are ***,an experiment is conducted to verify the feasibility of the proposed *** Root Mean Square Error(RMSE)of the three different resampling methods are *** results show the system resampling method has the highest prediction ***,the factors affected by the accuracy of the prediction are discussed.

关键词： Structural health monitoring fatigue crack prognostics particle filter lamb wave paris law

Extracting the Subsonic Anti-Symmetric lamb wave from a Submerged Thin Spherical Shell Backscattering Through Iterative Time Reversal

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Journal of Ocean University of China 2014年第4期13卷 589-596页

作者： YU Xiaotao PENG Linhui YU Gaokun School of Information Science and Engineering Ocean University of China State Key Laboratory of Acoustics Chinese Academy of Sciences

The extraction of the weakly excited anti-symmetric lamb wave from a submerged thin spherical shell backscattering is very difficult if the carrier frequency of the incident short tone burst is not at its frequency of greatest enhancement. Based on a single channel iterative time reversal technique, a method for isolating the subsonic anti-symmetric lamb wave is proposed in this paper. The approach does not depend on the form function of a thin shell and any other priori knowledge, and it is also robust in the presence of some stochastic noise. Both theoretical and numerical results show that the subsonic anti-symmetric lamb wave can be identified, even when the carrier frequency of the incident short tone burst is away from the frequency of greatest enhancement. The phenomenon may also be observed even in the case that the subsonic anti-symmetric lamb wave is submerged in the noise, other than the case with the Signal to Noise Ratio being less than 10 d B, when the amplitude of the noise is comparable with the specular wave. In this paper, each iteration process contains a traditional transmission and time reversal transmission steps. The two steps can automatically compensate the time delay of the subsonic anti-symmetric lamb wave relative to the specular wave and within-mode dispersion in the forward wave propagation.

关键词： backscattering lamb wave time reversal frequency of greatest enhancement SNR

lamb wave propagation in three-layered composites

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Chinese Journal of Acoustics 1995年第4期14卷 300-306页

作者： NING Wei and WANG Yaojun(The Laboratory of Modern Acoustics. Nanjing University, Nanjing 210093)

The characteristic equation for lamb waves in three-layered solid composites with arbitrary thickness of each layer are derived in this paper. Two important boundary conditions, i.e., rigid and slip boundary condition, between neighbored layers are considered and the dispersion curves with different boundaries are demonstrated. Numerical computations of the particle displacement distributions along the thickness direction are made for the lowest normal modcs s0 and a0.

关键词： Composite lamb wave Interface 'Spring' model