Journal articles: 'Lamb Wave'

1

Goldstein, R. V., and S. V. Kuznetsov. "Long-Wave Asymptotics of Lamb Waves." Mechanics of Solids 52, no. 6 (November 2017): 700–707. http://dx.doi.org/10.3103/s0025654417060097.

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Lee, Seung Seok, and Sang Whoe Dho. "Suppressing Technique of the Antisymmetric Mode by the Superposition of Lamb Waves Generated by Two Laser Beams in a Thin Plate." Key Engineering Materials 321-323 (October 2006): 103–7. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.103.

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We present a suppressing technique of the antisymmetric mode by superposition of Lamb waves generated by two laser beams in a thin plate. Two Lamb waves of the same frequency propagating from the opposite direction simultaneously arrive at the point of measurement and are superposed to compose one Lamb wave. The amplitude of the superposed Lamb wave depends on the distance between two laser beams. The suppressing of antisymmetric Lamb wave mode is accomplished by selecting the distance between two beams which simultaneously satisfies the condition of the anti-node(maximum) for the symmetric mode and the minimum for the antisymmetric mode. By this method, the antisymmetric Lamb wave mode is suppressed to the degree of 1.4% of the amplitude measured at zero distance between two beams.

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Park, Sang-Jin, Hoe-Woong Kim, and Young-Sang Joo. "Leaky Lamb Wave Radiation from a Waveguide Plate with Finite Width." Applied Sciences 10, no. 22 (November 16, 2020): 8104. http://dx.doi.org/10.3390/app10228104.

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In this paper, leaky Lamb wave radiation from a waveguide plate with finite width is investigated to gain a basic understanding of the radiation characteristics of the plate-type waveguide sensor. Although the leaky Lamb wave behavior has already been theoretically revealed, most studies have only dealt with two dimensional radiations of a single leaky Lamb wave mode in an infinitely wide plate, and the effect of the width modes (that are additionally formed by the lateral sides of the plate) on leaky Lamb wave radiation has not been fully addressed. This work aimed to explain the propagation behavior and characteristics of the Lamb waves induced by the existence of the width modes and to reveal their effects on leaky Lamb wave radiation for the performance improvement of the waveguide sensor. To investigate the effect of the width modes in a waveguide plate with finite width, propagation characteristics of the Lamb waves were analyzed by the semi-analytical finite element (SAFE) method. Then, the Lamb wave radiation was computationally modeled on the basis of the analyzed propagation characteristics and was also experimentally measured for comparison. From the modeled and measured results of the leaky radiation beam, it was found that the width modes could affect leaky Lamb wave radiation with the mode superposition and radiation characteristics were significantly changed depending on the wave phase of the superposed modes on the radiation surface.

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Sadler, J., and R. Gr Maev. "Experimental and theoretical basis of Lamb waves and their applications in material sciences." Canadian Journal of Physics 85, no. 7 (July 1, 2007): 707–31. http://dx.doi.org/10.1139/p07-082.

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The subject of Lamb waves contains a vast field of literature comprising many individual topics, with the current focus being the effective creation and use of Lamb waves in the fields of material characterization and nondestructive evaluation (NDE). This review chooses to focus on the more recent literature dealing with Lamb waves, giving introductions to a variety of topics. Because of the large amount of literature dealing with Lamb waves, many of the sections of this paper could themselves be expanded into their own literature review. This review begins with a brief introduction of Lamb waves comparing them to the acoustic bulk wave, and Rayleigh wave, and outlines the physics of a guided wave. It discusses the advantages of using guided waves, and theoretical techniques to model Lamb waves. In addition, the review discusses some of the various methods for the detection and creation of Lamb waves; techniques to detect, identify, and extract the mode from the acoustic signal; the use of Lamb waves in material characterization; flaw detection and flaw measurement; and finally examines the scattering of Lamb waves at plate ends and joints. While much of this work is experimentally based in nature, this review has attempted to also include theoretical work when possible. PACS Nos.: 43.90.+v, 81.70.Cv

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Ma, Shuyi, Guixian Zhang, Hongfeng Hou, and Lidong Wang. "Mutual Interactions of Lamb Waves in Nonlinear Elastic Plates." Metals 12, no. 12 (December 16, 2022): 2175. http://dx.doi.org/10.3390/met12122175.

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The mutual interactions of Lamb waves in nonlinear elastic plates are studied in this article. Many researchers have investigated the interactions of Lamb wave modes at nonlinear higher harmonics. However, little is known about nonlinearity-driven Lamb modulations from two primary modes with different frequencies. In this study, the existence of symmetric or antisymmetric mode due to Lamb wave mutual interactions is firstly theoretically formulated. Then, an approach is proposed to evaluate the intensity of phase velocity matching for selecting primary modes. Finally, the characteristics of the modulated wave generation are investigated and demonstrated. The generation of modulated waves in an aluminum plate and fatigue crack can be detected by mutual interactions of Lamb waves. The main contribution of this work is the proposed mutual interaction theory of Lamb waves in fatigue plates, which can guide fatigue detection in the metal plate.

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Radecki, Rafal, Wieslaw Jerzy Staszewski, and Tadeusz Uhl. "Impact of Changing Temperature on Lamb Wave Propagation for Damage Detection." Key Engineering Materials 588 (October 2013): 140–48. http://dx.doi.org/10.4028/www.scientific.net/kem.588.140.

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Lamb waves are the most widely used guided ultrasonic waves for structural damage detection. One of the major problems associate with Lamb wave propagation is the effect of temperature on wave propagation parameters. It is important that these parameters are more sensitive to damage than to varying temperature. The paper demonstrates how amplitude and arrival time of Lamb waves are affected by temperature. The analysis is performed for the experimental data gathered from Lamb wave propagation in a damaged aluminium plate. A simple clustering algorithm is used to distinguish between "undamaged" and "damaged" conditions in the presence of changing temperature.

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Elgamal, Hamada M., Zai Lin Yang, and Jian Wei Zhang. "Numerical Simulation of Lamb Wave Propagation in Isotropic Materials with Different Plate Thicknesses." Advanced Materials Research 1094 (March 2015): 500–504. http://dx.doi.org/10.4028/www.scientific.net/amr.1094.500.

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Understanding the characteristics of Lamb waves is very important for developing a structural health monitoring system. The propagation characteristics of Lamb waves are described in the form of dispersion curves, which are plots of phase/group velocities versus the product offrequency-thicknessgenerated by solving the Lamb wave equations. This paper presents a numerical modeling of Lamb waves’ amplitude behaviors for isotropic aluminum plate (Al 2024-T3). The numerical simulations were carried out using ANSYS by exciting the Lamb wave at the plate end in the frequency range of 150-200 kHz for different plate thicknesses.

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Yang, Zai Lin, Hamada M. Elgamal, and Yao Wang. "Damage Detection Using Lamb Waves (Review)." Advanced Materials Research 1028 (September 2014): 161–66. http://dx.doi.org/10.4028/www.scientific.net/amr.1028.161.

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Several techniques have been researched for detecting damage in plates. Each of these techniques offers their own unique advantages in detecting certain types of damage with various levels of analytical complexity. Lamb waves are guided waves that exist in thin walled structures. Because this type of wave can travel long distance with little attenuation, they have been studied intensively for structural health monitoring, especially in the past few decades. This paper presents an overview of using the Lamb waves in damage detection including the theory of lamb waves and the lamb-wave-based damage identification.

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Li, Chenggeng, Zhenhua Chen, Weibing Chen, and Chao Lu. "Study on Nonlinear Lamb Wave Test for Invisible Impact Damage on CFRP Laminates." Materials Evaluation 80, no. 3 (March 1, 2022): 43–51. http://dx.doi.org/10.32548/2022.me-04191.

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The impact damage imposed on carbon fiber–reinforced polymer (CFRP) materials used in aircraft fuselage may seriously affect flight safety. An ultrasonic testing method can be used to inspect for damage; however, in some cases of invisible or barely visible impact damage, linear ultrasound may not provide a clear indication of the underlying damage. Accordingly, a nonlinear Lamb wave technique was developed in this study to detect invisible impact damage (IID). First, a nonlinear Lamb wave testing platform was set, as well as damage areas with different impact energies. Second, the anisotropic propagation of Lamb waves was studied to determine the wave mode and the distribution of the transducers, and the linear parameters of the Lamb waves were determined. Last, three types of characteristic parameters of nonlinear Lamb waves were obtained for damage detection. As revealed from the results, the linear ultrasonic parameters of A0 mode Lamb waves can be applied to the detection of macro surface cracks, and the frequency shift, relative nonlinearity coefficient (RNC), and fluctuation coefficient of RNCs are highly sensitive to the detection of IID. Thus, a combination of nonlinear S0 Lamb waves and linear A0 Lamb waves can be used for IID and macro surface crack detection, respectively.

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Leonard, Kevin R., Eugene V. Malyarenko, and Mark K. Hinders. "Ultrasonic Lamb wave tomography." Inverse Problems 18, no. 6 (November 8, 2002): 1795–808. http://dx.doi.org/10.1088/0266-5611/18/6/322.

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11

Dieulesaint, E., D. Royer, A. Chaabi, and B. Formery. "Lamb wave graphic tablet." Electronics Letters 23, no. 19 (1987): 982. http://dx.doi.org/10.1049/el:19870690.

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Wang, Kai Sheng, Ru Hui He, and Zhi Min Zhao. "Phase Transformation Temperature of NiTi Alloy Sheet Examined by Lamb Wave." Advanced Materials Research 320 (August 2011): 359–62. http://dx.doi.org/10.4028/www.scientific.net/amr.320.359.

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In this study, the ultrasonic PZT transducers were used for exciting and receiving Lamb waves on NiTi alloy sheet. Lamb waves were measured when the temperature of the NiTi alloy changed. Analysis on frequency spectrums of the Lamb waves was also done. Some marked changes were observed in the dependence of the waveforms and the frequency spectrums of the Lamb waves versus temperature during phase transformation of NiTi alloy. The results show that phase transformation temperature of NiTi alloy sheet may be examined by Lamb wave method.

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Yang, Zai Lin, Hamada M. Elgamal, and Jian Wei Zhang. "Lamb-Wave-Based Damage Identification in Laminated Composite Plates." Advanced Materials Research 1014 (July 2014): 3–8. http://dx.doi.org/10.4028/www.scientific.net/amr.1014.3.

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With advantages including capability of propagation over a significant distance and high sensitivity to abnormalities and inhomogeneity near the wave propagation path, Lamb waves can be energised to disseminate in a structure and any changes in material properties or structural geometry created by a discontinuity, boundary or structural damage can be identified by examining the scattered wave signals. This paper presents an overview of the Lamb-wave-based damage identification in laminated composite plates including the formulation of lamb waves in an isotropic plate.

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Wang, Zijian, Pizhong Qiao, and Binkai Shi. "Nonpenetrating Damage Identification Using Hybrid Lamb Wave Modes from Hilbert-Huang Spectrum in Thin-Walled Structures." Shock and Vibration 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/5164594.

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Lamb waves have shown promising advantages for damage identification in thin-walled structures. Multiple modes of Lamb wave provide diverse sensitivities to different types of damage. To sufficiently utilize damage-related wave features, damage indices were developed by using hybrid Lamb wave modes from Hilbert-Huang spectra. Damage indices were defined as surface integrals of Hilbert-Huang spectra on featured regions determined by time and frequency windowing. The time windowing was performed according to individual propagation velocity of different Lamb wave mode, while the frequency windowing was performed according to the frequency of excitation. By summing damage indices for all transmitter-receiver pairs, pixels were calculated to reconstruct a damage map to characterize the degree of damage at each location on structure. Both numerical and experimental validations were conducted to identify a nonpenetrating damage. The results demonstrated that the proposed damage indices using hybrid Lamb wave modes are more sensitive and robust than the one using single Lamb wave mode.

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Li, Weibin, Shicheng Hu, and Mingxi Deng. "Combination of Phase Matching and Phase-Reversal Approaches for Thermal Damage Assessment by Second Harmonic Lamb Waves." Materials 11, no. 10 (October 12, 2018): 1961. http://dx.doi.org/10.3390/ma11101961.

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It is known that measurement and extraction of the tiny amplitude of second harmonic Lamb waves are the main difficulties for practical applications of the nonlinear Lamb wave technique. In this study, phase-reversal approaches and phase matching technique are combined to build up the second-harmonic generation (SHG) of Lamb waves. A specific Lamb wave mode pair, which satisfied phase matching conditions, is selected to ensure the generation of cumulative second harmonic waves. Lamb wave signals with the same frequency but in reverse phase, propagating in the given specimen, are added together to counteract the fundamental waves, and simultaneously to enhance the signals of the second harmonic generated. The obtained results show that the phase-reversal approach can enhance the signals of second harmonic Lamb waves, and effectively counteract that of the fundamental waves. The approach is applied to assess the thermal-induced material degradation in the stainless steel plates. Distinctions of the acoustic nonlinearity parameters under different degraded levels are clearly shown in an improved repeatable and reliable manner, while those of linear wave velocity in the specimens are neglectable. The experimental investigations performed indicate that the proposed approach can be taken as a promising alternative for assessment of material degradation in its early stages.

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Hosoya, Naoki, Ryosuke Umino, Atsushi Kanda, Itsuro Kajiwara, and Atsushi Yoshinaga. "Lamb wave generation using nanosecond laser ablation to detect damage." Journal of Vibration and Control 24, no. 24 (January 19, 2017): 5842–53. http://dx.doi.org/10.1177/1077546316687904.

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This paper proposes a non-contact damage detection method based on Lamb waves generated by laser ablation (LA). Previously, Lamb waves generated by contact-type sensors such as acoustic emission or piezoelectric zirconate titanate devices have been studied to detect damage. Lamb wave generation systems with embedded contact-type excitation devices to objective structures to be inspected may quickly realize large-area damage detection on a huge object such as an aircraft. However, replacing contact-type devices with non-contact devices in Lamb wave generation systems, the systems will have sufficient potential to excite under the specific conditions such as submerged target structures in liquid and high-temperature substances. The LA-generated Lamb waves that have amplitudes several hundred times larger than those generated by conventional laser-thermoelastically generated Lamb waves are of advantage from the viewpoint of the signal-to-noise ratio in the measurements. When the laser fluence reaches 1012–1014 W/m2, which is greater than that for laser-thermoelastic regime, a LA regime is induced. The amplitudes of the LA-generated Lamb waves might be higher than those of the laser-thermoelastically generated Lamb waves; this is within the scope of the assumption. Since the LA process entails a number of nonlinear processes such as melting, vaporization, and sublimation, it is important to confirm that LA could generate a Lamb wave and its mode. In this paper, Lamb waves that contain broadband frequency elements of more than several hundred kHz are generated by non-contact impulse excitation using LA, which is common in vibration tests in the high-frequency range, laser peening, propulsion of micro-aircraft, bolt loosening diagnosis, etc. The present method is evaluated by comparing the measured and calculated propagation phase and group velocities of the Lamb waves. Furthermore, the feasibility of our approach is demonstrated by non-contact damage detection against an aluminum alloy 2024 plate with a crack.

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Liu, G. R., J. Tani, K. Watanabe, and T. Ohyoshi. "Lamb Wave Propagation in Anisotropic Laminates." Journal of Applied Mechanics 57, no. 4 (December 1, 1990): 923–29. http://dx.doi.org/10.1115/1.2897662.

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The wave propagation in arbitrary anisotropic laminates is investigated on the basis of an exact theory. The dispersion relations of Lamb waves are determined for graphite/epoxy symmetric angle-ply laminates and hybrid composite ones which consist of carbon/epoxy and glass/epoxy layers. The dispersion and anisotropy of phase velocities for fundamental modes are discussed in detail. The energy distributions in the thickness direction of laminates are calculated for each kind of Lamb wave. A hybrid composite laminate is found to have better capability in absorbing impact energy by analyzing the strain energy distribution during the wave propagation. The results of the strain energy distribution are useful in determining the arrangement and the fiber orientation of the layers of hybrid composite laminates.

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Zhang, Yinghong, Zhenghua Qian, and Bin Wang. "Modes Control of Lamb Wave in Plates Using Meander-Line Electromagnetic Acoustic Transducers." Applied Sciences 10, no. 10 (May 18, 2020): 3491. http://dx.doi.org/10.3390/app10103491.

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The multimode and dispersion characteristics of Lamb waves make them difficult to apply to nondestructive evaluation. This paper presents a paired configuration of a meander-line coil electromagnetic acoustic transducer (EMAT) to generate a single-mode symmetric and antisymmetric Lamb wave in aluminum plates. In the paired structure, the bias magnetic field of the EMAT that generates symmetric mode Lamb waves is perpendicular to the plate surface, while the bias magnetic field of the EMAT that generates antisymmetric Lamb waves is parallel to the plate surface. The symmetric and antisymmetric exciting forces generated by these two EMATs are consistent with the dispersion equations of single symmetric and antisymmetric Lamb wave modes, respectively. The numerical simulations and experiments verified that the presented paired configurations of meander-line coil EMATs can effectively control the generation of single-mode Lamb waves at low frequencies.

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Schmitt, M., K. Schmidt, S. Olfert, J. Rautenberg, G. Lindner, B. Henning, and L. M. Reindl. "Detection of coatings within liquid-filled tubes and containers by mode conversion of leaky Lamb waves." Journal of Sensors and Sensor Systems 2, no. 1 (May 23, 2013): 73–84. http://dx.doi.org/10.5194/jsss-2-73-2013.

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Abstract. In this paper, a new acoustic sensor principle for coating detection within liquid-filled tubes and containers based on mode conversion of leaky Lamb waves is introduced. Leaky Lamb waves are excited and detected by single-phase transducers, which are attached on the outer side of a tube or container. By transmission time and amplitude measurements, coating formation within the liquid-filled tube and container is detected non-invasively. This new sensor principle is subdivided into the separate considerations of Lamb wave excitation, mode conversion and inverse mode conversion. The Lamb wave excitation by a single-phase transducer is visualized by scanning laser Doppler vibrometer imaging. The mode conversion process of leaky Lamb waves is measured by membrane hydrophone measurements and Schlieren visualization; afterwards, the measured emission angles are compared with the theoretical one. The inverse mode conversion process of pressure waves back to leaky Lamb waves is visualized by Schlieren images. By merging the results of Lamb wave excitation, mode conversion and inverse mode conversion, the new sensor concept is explained. Theoretical considerations and measurement results of adhesive tape coating inside a liquid-filled plastic tube and a liquid-filled stainless steel container verify the new acoustic sensor principle. Finally the measuring sensitivity and the technical realization are discussed.

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Santoni, Giola B., Lingyu Yu, Buli Xu, and Victor Giurgiutiu. "Lamb Wave-Mode Tuning of Piezoelectric Wafer Active Sensors for Structural Health Monitoring." Journal of Vibration and Acoustics 129, no. 6 (February 19, 2007): 752–62. http://dx.doi.org/10.1115/1.2748469.

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An analytical and experimental investigation of the Lamb wave-mode tuning with piezoelectric wafer active sensors (PWASs) is presented. The analytical investigation assumes a PWAS transducer bonded to the upper surface of an isotropic flat plate. Shear lag transfer of tractions and strains is assumed, and an analytical solution using the spacewise Fourier transform is reviewed, closed-form solutions are presented for the case of ideal bonding (i.e., load transfer mechanism localized at the PWAS boundary). The analytical solutions are used to derive Lamb wave-mode tuning curves, which indicate that frequencies exist at which the A0 mode or the S0 mode can be either suppressed or enhanced. Extensive experimental tests that verify these tuning curves are reported. The concept of “effective PWAS dimension” is introduced to account for the discrepancies between the ideal bonding hypothesis and the actual shear-lag load transfer mechanism. The paper further shows that the capability to excite only one desired Lamb wave mode is critical for practical structural health monitoring (SHM) applications such as PWAS phased array technique (e.g., the embedded ultrasonics structural radar (EUSR)) and the time reversal process (TRP). In PWAS phased array EUSR applications, the basic assumption of the presence of a single low-dispersion Lamb wave mode (S0) is invoked since several Lamb wave modes traveling at different speeds would disturb the damage imaging results. Examples are given of correctly tuned EUSR images versus detuned cases, which illustrate the paramount importance of Lamb wave-mode tuning for the success of the EUSR method. In the TRP study, an input wave packet is reconstructed at a transmission PWAS when the signal recorded at the receiving PWAS is reversed in the time domain and transmitted back to the original PWAS. Ideally, TRP could be used for damage detection without a prior baseline. However, the application of TRP to Lamb waves SHM is impended by the dispersive and multimodal nature of the Lamb waves. The presence of more then one mode usually produces additional wave packets on both sides of the original wave packet due to the coupling of the Lamb wave modes. The PWAS Lamb wave tuning technique described in this paper is used to resolve the side packets problem. Several tuning cases are illustrated. It is found that the 30kHz tuning of the A0 Lamb wave mode with a 16-count smoothed tone burst leads to the complete elimination of the side wave packets. However, the elimination was less perfect for the 290kHz tuning of the S0 mode due to the frequency sidebands present in the tone-burst wave packet.

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Xue, Weizhao, Wanjia Gao, Wenyi Liu, Huixin Zhang, and Ruiqing Guo. "Impact of Wedge Parameters on Ultrasonic Lamb Wave Liquid-Level Sensor." Sensors 22, no. 13 (July 4, 2022): 5046. http://dx.doi.org/10.3390/s22135046.

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The ultrasonic Lamb wave detection principle can realize the noncontact measurement of liquid level in closed containers. When designing an ultrasonic Lamb wave sensor, it is vital to thoroughly study and select the optimal wedge size at the front of the sensor. In this paper, firstly, we select the best working mode of Lamb waves according to their propagation dispersion curve in aluminum alloy, and we obtain the best angle of wedge through experiments. Secondly, we study the impact of the size of the wedge block on the results, and we obtain the selection method of wedge block parameters. The evaluations show that, when the frequency–thickness product is 3 MHz·mm, the Lamb waves work in the A1 mode, and the experimental effect is the best. At this time, the incident angle of the ultrasonic wave is 27.39°. The wedge thickness should be designed to avoid the near-field area of the ultrasonic field, and we should choose the length as odd multiples of 1/4 wavelength. The rules obtained from the experiment can effectively select the best working mode for ultrasonic Lamb waves, while also providing a basis for the design of the wedge block size in a Lamb wave sensor.

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Chen, Xiao, and Kai Xu. "Propagation Characteristic of Ultrasonic Lamb Wave." Applied Mechanics and Materials 157-158 (February 2012): 987–90. http://dx.doi.org/10.4028/www.scientific.net/amm.157-158.987.

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Ultrasonic wave transmitted in the plate is called Lamb wave. The dispersion characteristic of Lamb wave makes it very complicated to be used in material Nondestructive Testing (NDT). In order to solve this problem, the analysis of frequency-dispersion characteristic of Lamb wave is made in this paper, and the dispersion curves of the Lamb wave in specific plate are plotted, then the physical propagation model of Lamb wave is established. Under the analysis of FFT, the expressions of the Lamb wave in specific plate are obtained. By combining with the dispersion characteristic of the Lamb wave, the changes of waveform in different propagation distances are simulated. With the deep researches of new algorithms, Lamb wave will be applied in wider area.

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He, Juxing, Yahui Tian, Honglang Li, Zixiao Lu, Guiting Yang, and Jianyu Lan. "Extracting Lamb wave vibrating modes with convolutional neural network." Journal of the Acoustical Society of America 151, no. 4 (April 2022): 2290–96. http://dx.doi.org/10.1121/10.0010045.

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In recent years, micro-acoustic devices, such as surface acoustic wave (SAW) devices, and bulk acoustic wave (BAW) devices have been widely used in the areas of Internet of Things and mobile communication. With the increasing demand of information transmission speed, working frequencies of micro-acoustic devices are becoming much higher. To meet the emerging demand, Lamb wave devices with characteristics that are fit for high working frequency come into being. However, Lamb wave devices have more complicated vibrating modes than SAW and BAW devices. Methods used for SAW and BAW devices are no longer suitable for the mode extraction of Lamb wave devices. To solve this difficulty, this paper proposed a method based on machine learning with convolutional neural network to achieve automatic identification. The great ability to handle large amount of images makes it a good option for vibrating mode recognition and extraction. With a pre-trained model, we are able to identify and extract the first two anti-symmetric and symmetric modes of Lamb waves in varisized plate structures. After the successful use of this method in Lamb wave modes automatic extraction, it can be extended to all micro-acoustic devices and all other wave types. The proposed method will further promote the application of the Lamb wave devices.

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Dao, Phong B., and Wieslaw J. Staszewski. "Lamb Wave Based Structural Damage Detection Using Stationarity Tests." Materials 14, no. 22 (November 12, 2021): 6823. http://dx.doi.org/10.3390/ma14226823.

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Lamb waves have been widely used for structural damage detection. However, practical applications of this technique are still limited. One of the main reasons is due to the complexity of Lamb wave propagation modes. Therefore, instead of directly analysing and interpreting Lamb wave propagation modes for information about health conditions of the structure, this study has proposed another approach that is based on statistical analyses of the stationarity of Lamb waves. The method is validated by using Lamb wave data from intact and damaged aluminium plates exposed to temperature variations. Four popular unit root testing methods, including Augmented Dickey–Fuller (ADF) test, Kwiatkowski–Phillips–Schmidt–Shin (KPSS) test, Phillips–Perron (PP) test, and Leybourne–McCabe (LM) test, have been investigated and compared in order to understand and make statistical inference about the stationarity of Lamb wave data before and after hole damages are introduced to the aluminium plate. The separation between t-statistic features, obtained from the unit root tests on Lamb wave data, is used for damage detection. The results show that both ADF test and KPSS test can detect damage, while both PP and LM tests were not significant for identifying damage. Moreover, the ADF test was more stable with respect to temperature changes than the KPSS test. However, the KPSS test can detect damage better than the ADF test. Moreover, both KPSS and ADF tests can consistently detect damages in conditions where temperatures vary below 60 °C. However, their t-statistics fluctuate more (or less homogeneous) for temperatures higher than 65 °C. This suggests that both ADF and KPSS tests should be used together for Lamb wave based structural damage detection. The proposed stationarity-based approach is motivated by its simplicity and efficiency. Since the method is based on the concept of stationarity of a time series, it can find applications not only in Lamb wave based SHM but also in condition monitoring and fault diagnosis of industrial systems.

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Xu, Caibin, Zhibo Yang, and Mingxi Deng. "Weighted Structured Sparse Reconstruction-Based Lamb Wave Imaging Exploiting Multipath Edge Reflections in an Isotropic Plate." Sensors 20, no. 12 (June 21, 2020): 3502. http://dx.doi.org/10.3390/s20123502.

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Lamb wave-based structural health monitoring techniques have the ability to scan a large area with relatively few sensors. Lamb wave imaging is a signal processing strategy that generates an image for locating scatterers according to the received Lamb waves. This paper presents a Lamb wave imaging method, which is formulated as a weighted structured sparse reconstruction problem. A dictionary is constructed by an analytical Lamb wave scattering model and an edge reflection prediction technique, which is used to decompose the experimental scattering signals under the constraint of weighted structured sparsity. The weights are generated from the correlation coefficients between the scattering signals and the predicted ones. Simulation and experimental results from an aluminum plate verify the effectiveness of the present method, which can generate images with sparse pixel values even with very limited number of sensors.

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Xu, Yao, Chongcong Tao, and Jinhao Qiu. "Debonding detection of scarf-repaired composite laminates with laser ultrasonic Lamb waves." Journal of Physics: Conference Series 2184, no. 1 (March 1, 2022): 012041. http://dx.doi.org/10.1088/1742-6596/2184/1/012041.

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Abstract In this article, the Lamb wave at low frequency range is chosen to detect the debonding of scarf surface at different depths. The structure of interest is made up of two carbon fiber reinforced laminates with a scarf angle of 5° bonded together by an adhesive film. A 3D finite element model is established to calculate the propagation of Lamb waves with an artificial defect. Based on the wave front of out-of-plane displacement at different timepoint, the debonding area is located when propagating waves convert mode or reduce phase velocity. For validation, experiments are also conducted with wave-visualization technique. Lamb waves are excited by laser ultrasonic system and received by an acoustic emission sensor. The results agree with the simulation ones, which verify that the laser ultrasonic Lamb waves are effective for debond detection on the inclined plane of scarf-repaired composite laminates.

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Li, Cai, Hunag Xiao, and Zuo Xiaoqiong. "Damage Detection in a Plate Structure based on FBG sensing Technique under a Single-Mode Lamb Wave." International Journal of Online Engineering (iJOE) 14, no. 07 (July 27, 2018): 62. http://dx.doi.org/10.3991/ijoe.v14i07.8965.

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Lamb wave is widely acknowledged as one of the most encouraging tools for damage identification in plate structures, and relevant research has been conducted intensively. However Lamb wave modes have different wave structure, frequency dispersion and attenuation characteristics, which are sensitivity to different types of damages and it is difficult to solve such engineering problems by conventional techniques. Although the single pattern detection method has been researched by piezoelectric wafers, there is little research about FBG sensing detection under single-mode ultrasonic Lamb wave technique currently. So this paper puts forward a single-mode Lamb wave technique for crack detection based on Fiber Bragg Grating sensor, which is used to receive the waves in the plate. First of all, measuring principle of single-mode ultrasonic Lamb technique and demodulation principle of the FBG sensor are introduced. And simulation analysis in the acoustic field is devoted, whose results lay the foundation for the damage detection in the plate. Then, the experimental system is built by a single-mode Lamb wave excitation, and the feasibility of fiber Bragg grating sensors in single-mode excitation method is verified by experiments.

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Salim, M. N., M. N. M. Khairy, and T. Hayashi. "Effect of Oval Defect on Propagation of Fundamental Lamb Wave." Applied Mechanics and Materials 833 (April 2016): 49–58. http://dx.doi.org/10.4028/www.scientific.net/amm.833.49.

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Complicated Lamb wave propagation in structures can cause a misinterpretation in defect location and sizing during nondestructive inspections. A visualization of Lamb wave interactions with oval defects was carried out in our study to investigate the phenomenon of fundamental Lamb wave interaction around defect by using a reduced model of plate in ABAQUS. The visualized wave propagations with oval shape of through defects in plates demonstrated different patterns of wave interactions for the symmetric and anti-symmetric modes. The results also visualized the mode conversions around defects which converted from the incident waves. The visualized changes on the wave structures due to wave interaction with defects is important to increase our understanding on the guided wave propagation and reduce misinterpretation in nondestructive inspection when using the wave modes during inspection on large structures.

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Yeasin Bhuiyan, Md, Yanfeng Shen, and Victor Giurgiutiu. "Interaction of Lamb waves with rivet hole cracks from multiple directions." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 231, no. 16 (January 17, 2017): 2974–87. http://dx.doi.org/10.1177/0954406216686996.

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This paper presents the interaction of Lamb waves with rivet hole cracks from multiple directions of incident using the finite element approach. Lamb waves undergo scattering and mode conversion after interacting with the damage. Shear horizontal waves appear in the scattered waves because of the mode conversion. Instead of analyzing the whole large structure, the local damage area is analyzed using finite element analyses and analytical formulation is used to analyze the whole structure. The scatter fields are described in terms of wave damage interaction coefficients that involve scattering and mode conversion of Lamb waves. Lamb wave mode (S0 and A0) hit the damage from multiple directions and corresponding wave damage interaction coefficients are obtained around the damage. Harmonic analysis has been performed over the fundamental frequency domain and “scatter cubes” of complex-valued wave damage interaction coefficients are formed. The scatter cube provides the information of relative amplitude and phase of scattered waves around the damage that can be used for designing the sensor installation. An application based on real time domain signal has been illustrated for the problem of multiple-rivet-hole cracks using the scatter cubes with the analytical framework.

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Zhang, Li Shao, Huan Guo Chen, Jian Min Li, and Li Tian. "Lamb Wave-Based Damage Location Detection Method of Composite Plate." Advanced Materials Research 301-303 (July 2011): 1260–66. http://dx.doi.org/10.4028/www.scientific.net/amr.301-303.1260.

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To understand more about Lamb waves on composite laminates damage detection features, the Lamb wave group velocity dispersion curves are calculated and plotted by using dichotomy method in MATLAB. The signal parameters are chosen according to Group velocity dispersion curves. The dynamic response signals of the composite plate are obtained by finite element method. Damage location is calculated by the actual group velocity of Lamb wave and time of flight of the difference signal before and after damage.

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Adamova, M. E., and E. A. Zhukov. "Lamb Wave Analysis for Plate of Weak Ferromagnetic YFeO₃." Solid State Phenomena 265 (September 2017): 152–56. http://dx.doi.org/10.4028/www.scientific.net/ssp.265.152.

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The present work presents the analysis of Lamb waves in weak easy-axis ferromagnetic yttrium orthoferrite YFeO3, where the frequency and velocities spectrums were calculated based on dispersion equations. The specialties in calculated Lamb wave spectrum show the possibility of wave generation by an external source. The influence of the sample thickness on the characteristics of wave propagation in a plate is investigated.

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32

Firouzi, Kamyar, Amin Nikoozadeh, Thomas E. Carver, and Butrus Pierre T. Khuri-Yakub. "Lamb Wave Multitouch Ultrasonic Touchscreen." IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 63, no. 12 (December 2016): 2174–86. http://dx.doi.org/10.1109/tuffc.2016.2608781.

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33

Nikolovski, J. P., and D. Fournier. "Lamb wave (X, Y) detector." Electronics Letters 32, no. 12 (1996): 1147. http://dx.doi.org/10.1049/el:19960714.

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34

Hinders, Mark, Eugene Malyarenko, and James McKeon. "Contact scanning Lamb wave tomography." Journal of the Acoustical Society of America 104, no. 3 (September 1998): 1790–91. http://dx.doi.org/10.1121/1.423524.

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35

Palma, A., L. Palmieri, G. Socino, and E. Verona. "Lamb‐wave electroacoustic voltage sensor." Journal of Applied Physics 58, no. 8 (October 15, 1985): 3265–67. http://dx.doi.org/10.1063/1.335786.

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Alippi, A., P. Diodati, D. Maccari, and G. Socino. "Lamb wave interaction with light." Journal of Applied Physics 58, no. 4 (August 15, 1985): 1450–55. http://dx.doi.org/10.1063/1.336074.

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Wright, W., D. Hutchins, D. Jansen, and D. Schindel. "Air-coupled Lamb wave tomography." IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 44, no. 1 (January 1997): 53–59. http://dx.doi.org/10.1109/58.585190.

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Malyarenko, Eugene V., and Mark K. Hinders. "Ultrasonic Lamb wave diffraction tomography." Ultrasonics 39, no. 4 (June 2001): 269–81. http://dx.doi.org/10.1016/s0041-624x(01)00055-5.

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39

Choi, Jae-Seung, and Ronald A. Kline. "Multi-parameter Lamb wave tomography." KSME International Journal 14, no. 1 (January 2000): 1–10. http://dx.doi.org/10.1007/bf03184765.

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Qu, Wen Zhong, and D. J. Inman. "Temperature Influence Compensation for Lamb Wave Damage Detection." Applied Mechanics and Materials 105-107 (September 2011): 621–25. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.621.

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Among structural health monitoring (SHM) techniques, Lamb waves is frequently used as diagnostic tools to detect damage in plate-like structures. Temperature variation can cause significant changes in guided-wave propagation and transduction for SHM. In this paper, controlled experiments examine changes in Lamb wave propagation and transduction using PZT-5A piezoelectric wafers under quasi-statically varying temperature (from 5°C to 60°C). The baseline selection method and baseline signal stretch method are used to compensate the temperature influence on Lamb wave propagation. The results of the experiments demonstrate the effectiveness of the temperature compensation approach and the simulated damage on the plate can be detected effectively under elevated temperatures environment.

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Kim, Chun-Gon, Dae-Hyun Kim, and Young-Han Kim. "Lamb Wave Detection Using PZT and Fiber Optic Sensor." Proceedings of Conference of Kanto Branch 2004.10 (2004): 55–58. http://dx.doi.org/10.1299/jsmekanto.2004.10.55.

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Qiu, Jinhao, Jian Liu, Hongli Ji, and Liping Fei. "OS08F108 Lamb Wave Sensing Using Metal-core Piezoelectric Fibers." Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics 2011.10 (2011): _OS08F108——_OS08F108—. http://dx.doi.org/10.1299/jsmeatem.2011.10._os08f108-.

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43

Lee, Jeong Ki, Young H. Kim, and Ho Chul Kim. "Group Velocity of Lamb Wave S₀ Mode in Laminated Unidirectional CFRP Plates." Key Engineering Materials 297-300 (November 2005): 2213–18. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.2213.

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The elastic waves in the isotropic plate are dispersive waves with the characteristics of Lamb wave, however, S0 symmetric mode is less dispersive in the frequency region less than the first cut-off frequency. In the anisotropic plates such as CFRP plates, the propagation velocities vary with the directions as well as the dispersion of the Lamb wave, and the phase velocity direction does not accord with the group velocity direction. The phase velocity direction is equivalent the wave vector direction, while the group velocity direction is equivalent the energy flow direction. In this work, the group velocity dispersion curves were obtained by the dispersion relation of the Lamb wave in unidirectional CFRP plate with an orthotropic structure. The group velocities of the S0 symmetric mode in the frequency region less than the first cut-off frequency were corrected by applying the slowness surface. The propagation velocities of Lamb wave were decided by measuring the arrival time of the Lamb wave signals received with the two pinducers varying the propagating direction in the laminated unidirectional CFRP plates of 8, 16 and 24 plies having a volume fraction of 67%. The measured velocities are better agreement with corrected group velocity curve, except near the fiber direction at the cusp region. When the propagating direction is not accorded with the principal axis, the direction of the group velocities inclines toward the fiber direction in the unidirectional CFRP plates, suggesting that the energy propagates preferentially toward fiber direction.

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Li, Ruihua, Jing Luo, and Bo Hu. "Lamb Wave-Based Damage Localization Feature Enhancement and Extraction Method for Stator Insulation of Large Generators Using VMD and Wavelet Transform." Sensors 20, no. 15 (July 28, 2020): 4205. http://dx.doi.org/10.3390/s20154205.

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Lamb waves are used to locate any damage in the stator insulation structure of large generators. However, it is difficult to extract the features of Lamb wave signals in a strong background noise environment, thus significantly reducing the accuracy with which the damage is located. This paper proposes a method based on variational mode decomposition (VMD) and wavelet transform to enhance and extract the location features of stator insulation damage signals of large motors. First, considering that the characteristics of VMD are sensitive to noise, the Lamb wave detection signal is decomposed, denoised, and reconstructed; the reconstructed signal is then wavelet-transformed to extract the time of flight (TOF) of the damage-scattered wave as the damage location feature; finally, the damage location is determined using the TOF features. The proposed method is experimentally tested and verified under various noise environments. The results show that the VMD and wavelet transform methods can significantly improve the signal-to-noise ratio of Lamb wave detection signals and the accuracy with which the damage is located under strong background noise. This study extends the applicability of Lamb wave-based non-destructive detection of stator insulation damage in complex environments.

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Liu, Yu, Zheng Li, Ke Zhuang Gong, and Xian Yue Su. "A Quantitative Damage Identification Method for CF/EP Composite Laminates Based on Lamb Waves." Applied Mechanics and Materials 83 (July 2011): 13–18. http://dx.doi.org/10.4028/www.scientific.net/amm.83.13.

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This paper describes a quantitative damage identification method for CF/EP composite laminates based on Lamb waves excited by distributed PZT wafers. The fundamental symmetric mode S0 is considered to detect defects (hole) in the plate. The Morlet wavelet and the cross-correlation analysis are introduced as signal processing tools for determining the time-of-flight (ToF) of Lamb wave. Considering the difference of Lamb wave velocities in different directions in a composite plate, the relationship of Lamb wave velocity in a unidirectional fibre reinforced laminate is studied and validated experimentally and numerically. In addition, a defect identification approach is revealed based on a regular arrangement of PZT wafers. Then, on the basis of the relationship of the wave velocity and the ToF, the location of a hole is identified by proposed method. Results demonstrate that the method is feasible in quantitative diagnosis of composite structures.

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46

Ahmad, Zair Asrar Bin, Juan Miguel Vivar Perez, Christian Willberg, and Ulrich Gabbert. "Lamb wave propagation using Wave Finite Element Method." PAMM 9, no. 1 (December 2009): 509–10. http://dx.doi.org/10.1002/pamm.200910227.

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47

Nishida, Kiwamu, Naoki Kobayashi, and Yoshio Fukao. "Background Lamb waves in the Earth's atmosphere." Geophysical Journal International 196, no. 1 (November 5, 2013): 312–16. http://dx.doi.org/10.1093/gji/ggt413.

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Abstract Lamb waves of the Earth's atmosphere in the millihertz band have been considered as transient phenomena excited only by large events. Here, we show the first evidence of background Lamb waves in the Earth's atmosphere from 0.2 to 10 mHz, based on the array analysis of microbarometer data from the USArray in 2012. The observations suggest that the probable excitation source is atmospheric turbulence in the troposphere. Theoretically, their energy in the troposphere tunnels into the thermosphere at a resonant frequency via thermospheric gravity wave, where the observed amplitudes indeed take a local minimum. The energy leak through the frequency window could partly contribute to thermospheric wave activity.

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48

Chen, Xiao, and Kai Xu. "Wavelet Ridge Analysis of Lamb Wave." Advanced Materials Research 457-458 (January 2012): 484–87. http://dx.doi.org/10.4028/www.scientific.net/amr.457-458.484.

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Lamb wave has important application value in material nondestructive testing. It is a kind of ultrasonic guided wave propagating in thin plate material. It has the dispersion characteristic, which greatly limits its wide application in material evaluation. After continuous wavelet transformation, we extract the feature of ridge of Lamb wave signals by adopting crazy climber algorithm. Experimental results show that Lamb wave after transmission of a certain distance has the characteristics like asymptotic signal. The ridge can reflect the dispersion characteristic of Lamb wave.

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Aslam, Mohammed, Praveen Nagarajan, and Mini Remanan. "A Comparative Study of Wave Excitation in Plates Using Piezoelectric Transducers Operating at Different Modes." Materials Science Forum 969 (August 2019): 128–33. http://dx.doi.org/10.4028/www.scientific.net/msf.969.128.

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Structural health monitoring (SHM) and damage detection techniques have recently gained attention in various fields of engineering for preventing catastrophic failures. Among different SHM techniques, Lamb wave propagation methods are widely used as these waves can propagate large distance from a single source. Piezoelectric (PZT) transducers are used here as actuators and sensors to generate and receive wave signals. Most of the studies conducted on wave propagation in plates are by use of conventional d31 mode piezoelectric transducer. However, so far very few studies have been done using other types of PZT transducers. The primary objective of this paper is to determine and study the wave responses in a thin plate using different types of PZT transducers. The results indicate that the d31 and d33 type transducers generate Lamb waves, whereas d24 and d15 type transducers generate shear horizontal waves in two orthogonal directions. The study indicates that each of the transducers has its own directional property. The present study will be helpful for the application of Lamb waves and shear horizontal waves in plate structures

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LEE, TAE-HUN, IK-HWANG CHOI, and KYUNG-YOUNG JHANG. "THE NONLINEARITY OF GUIDED WAVE IN AN ELASTIC PLATE." Modern Physics Letters B 22, no. 11 (May 10, 2008): 1135–40. http://dx.doi.org/10.1142/s0217984908015966.

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The ultrasonic nonlinearity has been considered as a promising method to evaluate the material degradation, since it is sensitive to the minute variation of material properties. However, most researches were restricted to the nonlinear phenomena of bulk (longitudinal) wave propagation in the bulky medium. In the case of plate, however, the propagating elastic wave is Lamb wave of which characteristics are completely different with the bulk wave, and thus the separate study for the nonlinearity of Lamb wave is required. This paper reports the result of our basic study on the nonlinear phenomena of Lamb waves, which proposes conditions for practical application as well as for the cumulative propagation of quadratic harmonic frequency mode; (1) phase matching, (2) non-zero power flux, (3) group velocity matching, and (4) non-zero out-of-plane displacement.

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Journal articles on the topic 'Lamb Wave'

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