Results 191 to 200 of about 11,411 (229)
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Ultrasonic Lamb wave tomography in structural health monitoring
Smart Materials and Structures, 2011Variations of Lamb wave propagation reflect some changes in effective thickness and material properties caused by such structural flaws as corrosion, fatigue cracks, disbonds and voids that can then be mapped via a reconstructed tomographic image. Ultrasonic Lamb wave tomography can be used to evaluate structural integrity based on the variations in ...
Xiang Zhao +3 more
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Intelligent Structural Health Monitoring with Ultrasonic Lamb Waves
2020Structural health monitoring is a branch of machine learning where we automatically interpret the output of in situ sensors to assess the structural integrity and remaining useful lifetime of engineered systems. Sensors can often be permanently placed in locations that are inaccessible or dangerous, and thus not appropriate for traditional ...
Mark K. Hinders, Corey A. Miller
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Excitation of ultrasonic Lamb waves in composite membranes
1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium, 2002The excitation of ultrasonic Lamb waves by an interdigital transducer in a composite plate consisting of a piezoelectric thin film deposited on a nonpiezoelectric membrane is analyzed using the Green's function method. The amplitudes of the generated waves are obtained in terms of the charge density on transducer electrodes.
S.G. Joshi, Y. Jin
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Temperature effects in ultrasonic Lamb wave structural health monitoring systems
The Journal of the Acoustical Society of America, 2008There is a need to better understand the effect of temperature changes on the response of ultrasonic guided-wave pitch-catch systems used for structural health monitoring. A model is proposed to account for all relevant temperature-dependent parameters of a pitch-catch system on an isotropic plate, including the actuator-plate and plate-sensor ...
Francesco, Lanza di Scalea +1 more
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Reflection of ultrasonic Lamb waves produced by thin conducting strips
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 1999The reflection of ultrasonic Lamb waves produced by a periodic array of thin conducting strips deposited on a piezoelectric plate was investigated both theoretically and experimentally. A repetitively mismatched transmission line model was used to analyze the performance of the reflector.
B D, Zaitsev, S G, Joshi
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Ultrasonic surface waves and Lamb waves in fluid saturated porous solids
Proceedings., IEEE Ultrasonics Symposium, 2003The interactions of ultrasonic waves with a fluid/fluid-saturated porous solid interface and a fluid-saturated porous solid plate in a vacuum and in fluid have been studied. In the first case surface modes are generated and detected by using a periodically corrugated surface structure of a fluid-saturated porous solid; in the second case, the behavior ...
L. Adler, P.B. Nagy, Q. Xue
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Damage location by ultrasonic Lamb waves and piezoelectric rosettes
SPIE Proceedings, 2014An approach based on macro-fiber composite transducer rosettes and ultrasonic guided waves is proposed for damage location in plate-like structures. By using the directivity behaviour of the three macro-fiber composite sensors in each rosette, the direction of an incoming wave generated by scattering from damage can be estimated without knowledge of ...
Piotr Kijanka +3 more
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Lamb wave devices based on capacitive micromachined ultrasonic transducers
2002 IEEE Ultrasonics Symposium, 2002. Proceedings., 2003This paper describes the theory, design, and realization of a new type of Ultrasonic Lamb Wave Transducer. The excitation mechanism of this device is unlike any other as it relies on the Capacitive Micromachined Ultrasonic Transducer (CMUT). Built using fundamental integrated circuit techniques, this device has an insertion loss of 20 dB at an ...
M.H. Badi +4 more
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Theory of acoustic streaming generated by ultrasonic Lamb waves
The Journal of the Acoustical Society of America, 1998A theory on acoustic streaming generated by Lamb waves propagating in a thin composite membrane was developed. Using this theory, the mass-transport velocity in water, which is loaded on a 4-μm-thick membrane, due to Lamb waves at 4.7 MHz was calculated. The results are in good agreement with the experimental values measured by Moroney et al.
Zhemin Zhu +3 more
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Large-Panel Multi-Touch Ultrasonic Touchscreen Using Lamb Wave
2018 IEEE International Ultrasonics Symposium (IUS), 2018Touchscreen sensors are used in various devices, including smartphones, tablets, and large panels. Many existing touch-sensing technologies have disadvantages for application to large-size panels. Ultrasonic technology is one of the several methods developed to address this problem; however, it has only been implemented in small panels less than 23 ...
Ki ChangKang, Young HunKim, Kwan KyuPark
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