The Experts below are selected from a list of 34362 Experts worldwide ranked by ideXlab platform
Joseph L. Rose - One of the best experts on this subject based on the ideXlab platform.
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mode controlled Guided Wave tomography using annular array transducers for shm of water loaded plate like structures
Smart Materials and Structures, 2013Co-Authors: Jaya P Koduru, Joseph L. RoseAbstract:Ultrasonic Guided Wave tomography utilizes an array of permanently mounted transducers to detect and image defects like corrosion, cracks and delamination in structures. It is critical for successful tomography imaging to avoid the influences from external environmental conditions like water loading and changes in temperature. Water loading is particularly challenging as it affects the Guided Wave propagation in the structure. However, by taking advantage of the physical properties of Guided Waves it is possible to reduce its effect on the tomography images. Modal points on the dispersion curves can be found that have low out-of-plane displacement in their Wave structure and hence no leakage into the liquid on the structure. In this paper, the omnidirectional excitation of desired Guided Wave modes with annular array transducers is discussed. Guided Wave tomography of a steel plate like structure with a corrosion defect is studied under water loading conditions. The influence of water loading is overcome by exciting symmetric Guided Wave modes (S1) in the structure. Utilizing Guided Wave mode control it is shown that the defects in the structure can be easily discriminated from any artifacts in the images due to the liquid layer.
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Ultrasonic Guided Wave vibration formulation
2012Co-Authors: Cody Borigo, Yue Liang, Joseph L. RoseAbstract:A novel transient-Guided-Wave-based approach to predicting natural vibration frequencies and mode shapes of a semi-infinite plate has been developed. This theory uses the orthogonal propagating and evanescent Guided Wave modes to fully satisfy the elasticity structural vibration boundary value problem for the structure. This technique is able to accurately calculate natural resonant frequencies and full three-dimensional displacement fields in such a plate without making any classical plate theory assumptions, which neglect the crucially important through-thickness displacement field. In addition to solving the three-dimensional elasticity structural vibration problem and developing the through-thickness displacement field, further insight is obtained by relating transient Guided Wave propagation and steady-state vibration, as well as revealing the relative amplitude and phase of propagating Guided Wave modes associated with any particular plate vibration mode.
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Guided Wave propagation and mode differentiation in hollow cylinders with viscoelastic coatings
Journal of the Acoustical Society of America, 2008Co-Authors: Jing Mu, Joseph L. RoseAbstract:Guided Wave propagation theories have been widely explored for about one century. Earlier theories on single-layer elastic hollow cylinders have been very beneficial for practical nondestructive testing on piping and tubing systems. Guided Wave flexural (nonaxisymmetric) modes in cylinders can be generated by a partial source loading or any nonaxisymmetric discontinuity. They are especially important for Guided Wave mode control and defect analysis. Previous investigations on Guided Wave propagation in multilayered hollow cylindrical structures mostly concentrate on the axisymmetric Wave mode characteristics. In this paper, the problem of Guided Wave propagation in free hollow cylinders with viscoelastic coatings is solved by a semianalytical finite element (SAFE) method. Guided Wave dispersion curves and attenuation characteristics for both axisymmetric and flexural modes are presented. Due to the fact that dispersion curve modes obtained from SAFE calculations are difficult to differentiate from each ot...
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Coating Property Effects on Guided Wave Attenuation in Viscoelastic Coated Pipes
AIP Conference Proceedings, 2007Co-Authors: Joseph L. RoseAbstract:Guided Wave attenuation in a pipe with viscoelastic coating was studied through the calculation of attenuation dispersion curves. Coating property effects on Wave attenuation were investigated and some criteria have been acquired in terms of attenuation reduction. Appropriate coating property, frequency range and Wave type were recommended for future pipeline industry use based on the study. This study provides guidance for long‐range Guided Wave inspection in a real field pipeline under various coating conditions.
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Flexural Torsional Guided Wave Pipe Inspection
Quantitative Nondestructive Evaluation, 2006Co-Authors: L. Zhang, Joseph L. RoseAbstract:Based on the flexural torsional Guided Wave theory and its focusing technique, this paper demonstrates the defect detection capability of flexural torsional Guided Waves on multiple defects with different shapes and axial, circumferential locations in pipe.
G.c Carr - One of the best experts on this subject based on the ideXlab platform.
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Noncontact ultrasonic Guided Wave inspection of rails
Structural Health Monitoring, 2013Co-Authors: S.a Mariani, P.b Kijanka, Wiesław J. Staszewski, T. A. Nguyen, Robert Phillips, Mahmood Fateh, Francesco Lanza Di Scalea, G.c CarrAbstract:This article describes a new system for high-speed and noncontact rail integrity evaluation being developed at the University of California at San Diego. A prototype using an ultrasonic air-coupled Guided Wave signal generation and air-coupled signal detection has been tested at the University of California at San Diego Rail Defect Farm. In addition to a real-time statistical analysis algorithm, the prototype uses a specialized filtering approach due to the inherently poor signal-to-noise ratio of the air-coupled ultrasonic measurements in rail steel. The laboratory results indicate that the prototype is able to detect internal rail defects with a high reliability. Extensions of the system are planned to add rail surface characterization to the internal rail defect detection. In addition to the description of the prototype and test results, numerical analyses of ultrasonic Guided Wave propagation in rails have been performed using a Local Interaction Simulation Approach algorithm and some of these results are shown. The numerical analysis has helped designing various aspects of the prototype for maximizing its sensitivity to defects. © The Author(s) 2013.
Sebastien Tanzilli - One of the best experts on this subject based on the ideXlab platform.
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High performance Guided-Wave asynchronous heralded single photon source
Optics Letters, 2005Co-Authors: Olivier Alibart, Pascal Baldi, Daniel Barry Ostrowsky, Sebastien TanzilliAbstract:We report on a Guided Wave heralded photon source based on the creation of non-degenerate photon pairs by spontaneous parametric down conversion in a Periodically Poled Lithium Niobate Waveguide. Using the signal photon at 1310 nm as a trigger, a gated detection process permits announcing the arrival of single photons at 1550 nm at the output of a single mode optical fiber with a high probability of 0.38. At the same time the multi-photon emission probability is reduced by a factor of 10 compared to poissonian light sources. Relying on Guided Wave technologies such as integrated optics and fiber optics components, our source offers stability, compactness and efficiency and can serve as a paradigm for Guided Wave devices applied to quantum communication and computation using existing telecom networks.
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Guided Wave technology for a telecom Wavelength heralded single photon source
2004Co-Authors: Olivier Alibart, Sebastien Tanzilli, D. B. Ostrowsky, Pascal BaldiAbstract:We report on a Guided Wave heralded photon source based on the creation of non-degenerate photon pairs by spontaneous parametric down conversion in a Periodically Poled Lithium Niobate Waveguide. Using the signal photon at 1310 nm as a trigger, a gated detection process permits announcing the arrival of single photons at 1550 nm at the output of a single mode optical fiber with the best probability to date of 0.38. The multi-photon emission probability is reduced by a factor of 10 compared to poissonian light sources. Relying on Guided Wave technologies such as integrated optics and fiber optics components, our source offers stability, compactness and efficiency and can serve as a paradigm for Guided Wave devices applied to quantum communication and computation using existing telecom networks.
Ajay Nahata - One of the best experts on this subject based on the ideXlab platform.
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planar plasmonic terahertz Guided Wave devices
Quantum Electronics and Laser Science Conference, 2009Co-Authors: Amit Agrawal, Ajay NahataAbstract:We describe the realization of planar plasmonic THz Guided-Wave devices, including straight Waveguides, Y-splitters and 3dB-couplers, using periodically perforated metal films. These perforated films behave as effective media whose Waveguiding properties can be broadly engineered.
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planar plasmonic terahertz Guided Wave devices
Optics Express, 2008Co-Authors: Amit Agrawal, Ajay NahataAbstract:We describe the experimental realization of planar plasmonic THz Guided-Wave devices using periodically perforated metal films. These perforated films behave as effective media for which the dielectric function can be broadly engineered. We initially use transmission measurements to measure the complex dielectric constants of these effective media and show experimentally that the effective plasma frequency corresponds to the cutoff frequency of the rectangular apertures. Using these structures, we demonstrate not only straight planar THz Waveguides, but also more complex devices such as Y-splitters and 3-dB couplers. In each of these embodiments, we demonstrate that the propagating THz radiation is well confined in both the in-plane and out-of-plane axes. This approach opens exciting new avenues for both passive and active THz Guided-Wave devices and circuits.
Fucai Li - One of the best experts on this subject based on the ideXlab platform.
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Defect Detection for Fiber Reinforced Plastics Rod of Composite Insulator with Ultrasonic Guided Wave
Diangong Jishu Xuebao Transactions of China Electrotechnical Society, 2017Co-Authors: H Deng, Q Lu, D Dai, Lin Chen, Fucai LiAbstract:© 2017, The editorial office of Transaction of China Electrotechnical Society. All right reserved. Statistics showed that the insulator damages caused by fracture of fiber reinforced plastics (FRP) rod accounted for a large proportion in high voltage line serious accidents. For rapid and accurate detection on the defect of FRP rod, this paper presented a new method: ultrasonic Guided Wave. According to Guided Wave theory, characteristics of Guided Wave propagation in FRP rod from 110kV composite insulator were obtained. The frequency of excitation signal used in simulation and experiment was preliminarily determined by the longitudinal and torsional mode dispersion curves of Guided Wave. Through finite element simulation, Waveforms of Guided Wave propagating in FRP rod with and without defect were presented. Experiment based on theoretical analysis and simulation results was carried out. It is shown that both of 10-cycle 40kHz and 20-cycle 32kHz L(0, 1) Guided Waves could efficiently detect defection in FRP rod, and the former could detect the accurate position of defect while the latter is more suitable for longer FRP rod. Within a certain range, the longer FRP rod is, the more obvious flaw Waves are and the better performance of detection is. It is feasible and effective to defect detection of FRP rod from composite insulator with ultrasonic Guided Wave technology.
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Detection for composite insulator based on ultrasonic Guided Wave
Gaodianya Jishu High Voltage Engineering, 2016Co-Authors: H Deng, Q Lu, D Dai, Lin Chen, Fucai LiAbstract:© 2016, High Voltage Engineering Editorial Department of CEPRI. All right reserved. In order to detect composite insulator defects accurately and quickly, we presented a method of detecting composite insulators based on ultrasonic Guided Wave. According to the ultrasonic Guided Wave propagation theory, we established simplified models of fiber reinforced plastics (FRP) rod and composite insulators, and solved their dispersion equations. Afterwards, finite element numerical simulation for those two kinds of models was implemented in accordance with the calculated dispersion curves, and the sensitivities of various defects by detecting composite insulator with different low frequency L(0, 1) longitudinal ultrasonic Guided Wave were analyzed. We carried out experiments on the basis of theory analysis and simulation results for detecting composite insulators. The results show that, by using 30~150 kHz low frequency L(0, 1) longitudinal ultrasonic Guided Wave, we can detect the FRP rod defect of 2 mm in depth, 8 mm in circumferential length. Also, we can find that the silicone rubber coating tends to attenuate the propagating energy and can severely degrade the performance of a Guided Wave test if both of excitation and receiver are positioned on the silicone rubber outside. On the contrary, if the excitation and reception point change to the FRP rod inside, by using 40~100 kHz low frequency L(0, 1) longitudinal ultrasonic Guided Wave, we can detect the composite insulator defects of 14 mm in depth, 40 mm in circumferential length. In conclusion, it is feasible to defect detection of composite insulators with ultrasonic Guided Wave technology.
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Guided Wave and damage detection in composite laminates using different fiber optic sensors.
Sensors (Basel Switzerland), 2009Co-Authors: Fucai Li, Kazuro Kageyama, Hideaki Murayama, Takehiro ShiraiAbstract:Guided Wave detection using different fiber optic sensors and their applications in damage detection for composite laminates were systematically investigated and compared in this paper. Two types of fiber optic sensors, namely fiber Bragg gratings (FBG) and Doppler effect-based fiber optic (FOD) sensors, were addressed and Guided Wave detection systems were constructed for both types. Guided Waves generated by a piezoelectric transducer were propagated through a quasi-isotropic carbon fiber reinforced plastic (CFRP) laminate and acquired by these fiber optic sensors. Characteristics of these fiber optic sensors in ultrasonic Guided Wave detection were systematically compared. Results demonstrated that both the FBG and FOD sensors can be applied in Guided Wave and damage detection for the CFRP laminates. The signal-to-noise ratio (SNR) of Guided Wave signal captured by an FOD sensor is relatively high in comparison with that of the FBG sensor because of their different physical principles in ultrasonic detection. Further, the FOD sensor is sensitive to the damage-induced fundamental shear horizontal (SH(0)) Guided Wave that, however, cannot be detected by using the FBG sensor, because the FOD sensor is omnidirectional in ultrasound detection and, in contrast, the FBG sensor is severely direction dependent.
