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Acoustic emission (AE) source localization has been used to visualize progress failures generated in a wide variety of materials. In the conventional approaches, AE source localization algorithms assume that the AE signal is propagated as a straight line. However, it is supposed that progress failures form heterogeneity of elastic wave velocity distributions. Hence, with the conventional source localization, it is expected that the localization accuracy is reduced in heterogeneous materials since diffraction and refraction waves are generated. Thus, if the straight propagation waves are classified, conventional source localizations are performed in the heterogeneous materials. The self-organizing map (SOM) is one of the unsupervised learning methods, and the SOM has potential to classify straight propagation waves for the source localizations. However, the application of classified AE signals in source localization is not popular. If classified AE signals are applied to the time difference of arrival (TDOA) method, which is the popular localization method, it is expected that number of visualized sources are decreased because the algorithm does not consider the selection of the propagated wave. Although ray tracing has potential to localize a larger number of sources than the TDOA method, it is expected that the localized sources are less accurate in comparison with results of the TDOA method. In this study, classified waves were applied to two of the source localizations, and model tests based on pencil-lead breaks (PLBs) generating artificial AE sources were conducted to validate the performance of the source localizations with classified waves. The results of the validation confirmed that the maximum error in the TDOA method is larger in comparison with ray tracing conducted with 20 mm intervals of source candidates. Moreover, ray tracing localizes the same number of sources as the number of PLB tests. Therefore, ray tracing is expected to more practically localize AE sources than the TDOA method if classified waves are applied.
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Pierre, Christophe, Matthew P. Castanier, and Wan Joe Chen. "Wave Localization in Multi-Coupled Periodic Structures: Application to Truss Beams." Applied Mechanics Reviews 49, no. 2 (February 1, 1996): 65–86. http://dx.doi.org/10.1115/1.3101889.
A tutorial and a review of recent developments in the area of localization in linear structural dynamics problems are presented. Particular emphasis is placed on multi-coupled nearly periodic structures, which carry more than one wave type. First, background on perfectly periodic structures is provided, including both the wave and modal descriptions of the dynamics. A wave transfer matrix formulation for disordered periodic structures is then presented, which is well suited to the analysis of localized dynamics. Next, stochastic analysis tools are introduced that allow one to quantify the degree of localization in an asymptotic sense. Means of calculating these localization factors as the Lyapunov exponents of the system wave transfer matrix are discussed. Finally, the general theory is illustrated on an example multi-coupled structure - a planar truss beam which carries four pairs of waves. The propagation of waves in the disordered structure is examined, and Lyapunov exponents are calculated. In addition to the localization of the incident wave, significant mixing of the various wave types occurs, causing the leakage of energy to the least localized waves, and enabling sustainment of motion according to the smallest Lyapunov exponent.
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Sivan, U., and A. Sa'ar. "Light Wave Localization in Dielectric Wave Guides." Europhysics Letters (EPL) 5, no. 2 (January 15, 1988): 139–44. http://dx.doi.org/10.1209/0295-5075/5/2/009.
PUROHIT, GUNJAN, PRERANA SHARMA, and R. P. SHARMA. "Filamentation of laser beam and suppression of stimulated Raman scattering due to localization of electron plasma wave." Journal of Plasma Physics 78, no. 1 (October 11, 2011): 55–63. http://dx.doi.org/10.1017/s0022377811000419.
AbstractThis paper presents the effect of laser beam filamentation on the localization of electron plasma wave (EPW) and stimulated Raman scattering (SRS) in unmagnetized plasma when relativistic and ponderomotive nonlinearities are operative. The splitted profile of the laser beam is obtained due to uneven focusing of the off-axial rays. The semi-analytical solution of the nonlinearly coupled EPW equation in the presence of laser beam filaments has been found. It is observed that due to this nonlinear coupling between these two waves, localization of EPW takes place. Stimulated Raman scattering of this EPW is studied and back reflectivity has been calculated. Further, the localization of EPW affects the eigenfrequency and damping of plasma wave. The new enhanced damping of the plasma wave has been calculated and it is found that the SRS process gets suppressed due to the localization of plasma wave in laser beam filamentary structures.
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Liu, Runjie, Chaoqi Ma, Qionggui Zhang, Xu Gao, and Lianji Zhang. "An Improved P-wave Peak Location Method Based on Pan-Tompkins Algorithm." Journal of Physics: Conference Series 2759, no. 1 (May 1, 2024): 012006. http://dx.doi.org/10.1088/1742-6596/2759/1/012006.
Abstract Electrocardiogram (ECG) signal can reflect the health of the heart, and P wave is an important part of ECG signal, which reflects the excitatory conduction process of the heart. By precisely locating the P waves in the ECG signal, important information about heart disease can be obtained. In this paper, a method of P-wave peak localization based on Pan-Tompkins algorithm is proposed. Firstly, the ECG signal is decomposed by wavelet transform, and the coefficients of each layer are processed to filter out the noise such as baseline drift and electromyographic interference in the ECG signal. After the location of R wave in the signal was found by the Pan-Tompkins algorithm, the QRS wave was eliminated, and then the possible P wave location was found by the improved Pan-Tompkins algorithm. Finally, the correct P wave was screened by a screening strategy. Experimental results show that the sensitivity and accuracy of the P-wave localization algorithm proposed in this paper reach 94.78% and 95.10%, respectively. It shows that the proposed algorithm has good performance for P-wave localization.
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Ye, Ling, George Cody, Minyao Zhou, Ping Sheng, and Andrew Norris. "Observation of acoustic wave localization." Journal of the Acoustical Society of America 90, no. 4 (October 1991): 2356. http://dx.doi.org/10.1121/1.402125.
Maihemutijiang, Maiheliya. "Study on Single-phase Ground Fault Localisation in Distribution Networks Based on Transient Travelling Waves." Academic Journal of Science and Technology 7, no. 2 (September 27, 2023): 81–85. http://dx.doi.org/10.54097/ajst.v7i2.11946.
China's low and medium voltage distribution networks are mostly grounded by small currents, and single-phase grounding faults are frequent and their fault characteristics are weak, so that the traditional fault localization schemes may fail. In order to effectively solve the problem of single-phase grounding fault localization in distribution networks, the traveling wave localization technology is applied in distribution networks, which is expected to realize fast and accurate fault localization in distribution networks. Firstly, the paper analyzes the characteristics of traveling wave signals in distribution networks and those in transmission networks, and proves the feasibility of the traveling wave localization method applied to distribution networks. Secondly, the transient electrical quantities after a single-phase ground fault occurs in the distribution network are characterized, and it is concluded that in the fault transient process, nonlinear and nonsmooth signals appear in the faulted and non-faulted lines, and effective information is extracted for fault localization using the traveling wave method. Finally, in the case of abnormal traveling wave data during fault localization, single-end localization is carried out using the initial wave head arrival moment and reflection wave arrival moment of the traveling wave signal of the side branch to ensure accurate localization, and simulation verification is carried out using PSCAD/EMPDC.
Rimal, Nischal. "Impact Localization Using Lamb Wave and Spiral FSAT." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1388672483.
Vidiyala, Sai Krishna. "Simultaneous localization and mapping with radio signals." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/24138/.
Simultaneous localization and mapping is a concept that originated in the robotics area, where robots are traditionally equipped with a laser sensor and can navigate and map an unknown surrounding environment. High-definition distance estimates and very narrow steering beams are provided
by high-accuracy SLAM technologies based on laser and mechanical steering devices. Unfortunately, these technologies are prohibitively expensive and cumbersome, and they cannot be integrated into mobile devices. This Thesis investigates millimeter wave (mmWave) radar technology to solve a SLAM problem. The technologies used are consistent with the concept of a personal mobile radar and they can be considered a proof-of-concept for further development of this concept.
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Lotti, Marina, and Marina Lotti. "Experimental characterization of millimeter-wave radars for mapping and localization." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/19891/.
L’attività di tesi è inquadrata nell’ambito del progetto europeo PRIMELOC (Personal Radars for Radio Imaging and Infrastructure-less Localization) il cui scopo è quello di validare il concetto di radar personale per fornire servizi automatici di localizzazione e di mappatura degli ambienti indoor, evitando l’introduzione di infrastrutture ad hoc. Per far ciò, si vogliono sfruttare i dispositivi di future generazioni wireless che usano onde millimetriche, per costruire mappe di luoghi indoor. Le mappe sono ottenute scannerizzando l’ambiente circostante attraverso l’uso di massive antenna arrays ad onde millimetriche e di particolari algoritmi per la localizzazione e il mapping simultanei (simultaneous localization and mapping - SLAM). Per la validazione sperimentale del concetto di Personal Radar è fondamentale l’esecuzione di diverse campagne di misura in ambienti realistici. I dati raccolti da esse devono essere valutati e processati al fine di renderli adatti come input degli algoritmi di SLAM.
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Woolard, Americo Giuliano. "Supplementing Localization Algorithms for Indoor Footsteps." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/78698.
The data rich nature of instrumented civil structures has brought attention to alternative applications outside of the traditional realm of structural health monitoring. An interest has been raised in using these vibration measurements for other applications such as human occupancy. An example of this is to use the vibrations measured from footsteps to locate occupants within a building. The localization of indoor footsteps can yield several benefits in areas such as security and threat detection, emergency response and evacuation, and building resource management, to name a few. The work described herein seeks to provide supplementary information to better define the problem of indoor footstep localization, and to investigate the use of several localization techniques in a real-world, operational building environment. The complexities of locating footsteps via indoor vibration measurements are discussed from a mechanics perspective using prior literature, and several techniques developed for localization in plate structures are considered for their applicability to indoor localization. A dispersion compensation tool is experimentally investigated for localization in an instrumented building. A machine learning approach is also explored using a nearest neighbor search. Additionally, a novel instrumentation method is designed based on a multi-point coupling approach that provides directional inference from a single point of measurement. This work contributes to solving the indoor footstep localization problem by consolidating the relevant mechanical knowledge and experimentally investigating several potential solutions. Ph. D.
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Bordiga, Giovanni. "Homogenization of periodic lattice materials for wave propagation, localization, and bifurcation." Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/259019.
The static and dynamic response of lattice materials is investigated to disclose and control the connection between microstructure and effective behavior. The analytical methods developed in the thesis aim at providing a new understanding of material instabilities and strain localizations as well as effective tools for controlling wave propagation in lattice structures.
The time-harmonic dynamics of arbitrary beam lattices, deforming flexurally and axially in a plane, is formulated analytically to analyze the influence of the mechanical parameters on the dispersion properties of the spectrum of Floquet-Bloch waves. Several forms of dynamic localizations are shown to occur for in-plane wave propagation of grid-like elastic lattices. It is demonstrated that lattices of rods, despite being `simple' structures, can exhibit a completely different channeled response depending on the characteristics of the forcing source (i.e. frequency and direction) as well as on the slenderness of the elastic links. It is also shown how the lattice parameters can be tuned to attain specific dispersion properties, such as flat bands and sharp Dirac cones.
In the research field of material instabilities, a key result proposed in this thesis is the development of both static and dynamic homogenization methods capable of accounting for second-order effects in the macroscopic response of prestressed lattices. These methods, the former based on an incremental strain-energy equivalence and the latter based on the asymptotic analysis of lattice waves, allow the identification of the incremental constitutive operator capturing the macroscopic incremental response of arbitrary lattice configurations. The homogenization framework has allowed the systematic analysis of prestress-induced phenomena on the incremental response of both the lattice structure and its `effective' elastic solid, which in turn has enabled the identification of the complex interplay between microstructure, prestress, loss of ellipticity (shear band formation) and short-wavelength bifurcations.
Potential new applications for the control of wave propagation are also shown to be possible by leveraging the inclusion of second-order terms in the incremental dynamics. In particular, the tunability of the prestress state in a square lattice structure has been exploited to obtain dynamic interfaces with designable transmission properties. The interface can be introduced in a material domain by selectively prestressing the desired set of ligaments and the prestress level can be tuned to achieve total reflection, negative refraction, and wave channeling.
The obtained results open new possibilities for the realization of engineered materials endowed with a desired constitutive response, as well as to enable the identification of novel dynamic material instabilities.
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Bordiga, Giovanni. "Homogenization of periodic lattice materials for wave propagation, localization, and bifurcation." Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/259019.
The static and dynamic response of lattice materials is investigated to disclose and control the connection between microstructure and effective behavior. The analytical methods developed in the thesis aim at providing a new understanding of material instabilities and strain localizations as well as effective tools for controlling wave propagation in lattice structures.
The time-harmonic dynamics of arbitrary beam lattices, deforming flexurally and axially in a plane, is formulated analytically to analyze the influence of the mechanical parameters on the dispersion properties of the spectrum of Floquet-Bloch waves. Several forms of dynamic localizations are shown to occur for in-plane wave propagation of grid-like elastic lattices. It is demonstrated that lattices of rods, despite being `simple' structures, can exhibit a completely different channeled response depending on the characteristics of the forcing source (i.e. frequency and direction) as well as on the slenderness of the elastic links. It is also shown how the lattice parameters can be tuned to attain specific dispersion properties, such as flat bands and sharp Dirac cones.
In the research field of material instabilities, a key result proposed in this thesis is the development of both static and dynamic homogenization methods capable of accounting for second-order effects in the macroscopic response of prestressed lattices. These methods, the former based on an incremental strain-energy equivalence and the latter based on the asymptotic analysis of lattice waves, allow the identification of the incremental constitutive operator capturing the macroscopic incremental response of arbitrary lattice configurations. The homogenization framework has allowed the systematic analysis of prestress-induced phenomena on the incremental response of both the lattice structure and its `effective' elastic solid, which in turn has enabled the identification of the complex interplay between microstructure, prestress, loss of ellipticity (shear band formation) and short-wavelength bifurcations.
Potential new applications for the control of wave propagation are also shown to be possible by leveraging the inclusion of second-order terms in the incremental dynamics. In particular, the tunability of the prestress state in a square lattice structure has been exploited to obtain dynamic interfaces with designable transmission properties. The interface can be introduced in a material domain by selectively prestressing the desired set of ligaments and the prestress level can be tuned to achieve total reflection, negative refraction, and wave channeling.
The obtained results open new possibilities for the realization of engineered materials endowed with a desired constitutive response, as well as to enable the identification of novel dynamic material instabilities.
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Reinwald, Michael. "Wave propagation in mammalian skulls and its contribution to acoustic source localization." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS244.
La précision avec laquelle le dauphin localise les sources sonores est excellente, que les sources soient situées dans le plan médial ou dans le plan transverse. Cette faculté est contre-intuitive étant donné que les dauphins n’ont pas d’oreille externe (pavillon), qui joue un rôle important chez les autres mammifères pour la localisation de sources en élévation. Dans cette thèse, des simulations tridimensionnelles ont été réalisées pour déterminer l’influence de la conduction osseuse du son dans le crâne d’un dauphin commun à bec court sur la pression acoustique au voisinage de l’oreille. La modalisation n’a pas permis de mettre en évidence d’encoches spectrales telles que celles créées par le pavillon de l’oreille externe des humains et qui codent chez celui-ci l’élévation de la source sonore. Une série d’expériences sur un crâne de dauphin, immergé dans une piscine, a permis de mesurer directement la conduction osseuse dans la mandibule. Les formes d’ondes complètes des sons reçus aux récepteurs fixés sur la mandibule, et particulièrement la coda du signal, a pu être utilisée avec succès pour obtenir la position de sources en utilisant un algorithme de corrélation. Ce résultat, qui devra être conforté par la réalisation d’autres expériences, suggère que le système auditif du dauphin pourrait utiliser la coda des signaux reçus lors de l’écholocation. Enfin, des simulations 2D ont permis de mettre en évidence le potentiel bénéfice du couplage de la conduction osseuse du son avec la propagation dans des structures graisseuses de la tête du dauphin The spatial accuracy of source localization by dolphins has been observed to be equally accurate independent of source azimuth and elevation. This ability is counter-intuitive if one considers that humans and other species have presumably evolved pinnae to help determine the elevation of sound sources, while cetaceans have actually lost them. In this work, 3D numerical simulations are carried out to determine the influence of bone-conducted waves in the skull of a short-beaked common dolphin on sound pressure in the vicinity of the ears. The skull is not found to induce any salient spectral notches, as pinnae do in humans, that the animal could use to differentiate source elevations in the median plane. Experiments are conducted in a water tank by deploying sound sources on the horizontal and median plane around a skull of a dolphin and measuring bone-conducted waves in the mandible. Their full waveforms, and especially the coda, can be used to determine source elevation via a correlation-based source localization algorithm. While further experimental work is needed to substantiate this speculation, the results suggest that the auditory system of dolphins might be able to localize sound sources by analyzing the coda of biosonar echoes. 2D numerical simulations show that this algorithm benefits from the interaction of bone-conducted sound in a dolphin's mandible with the surrounding fats
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LaPenta, Jason Michael. "Real-time 3-d localization using radar and passive surface acoustic wave transponders." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/41738.
Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2007. Includes bibliographical references (p. 141-150). This thesis covers ongoing work into the design, fabrication, implementation, and characterization of novel passive transponders that allow range measurements at short range and at high update rates. Multiple RADAR measurement stations use phase-encoded chirps to selectively track individual transponders by triangulation of range and/or angle measurements. Nanofabrication processes are utilized to fabricate the passive surface acoustic wave transponders used in this thesis. These transponders have advantages over existing solutions with their small size (mm x mm), zero-power, high-accuracy, and kilohertz update rates. Commercial applications such as human machine interfaces, virtual training environments, security, inventory control, computer gaming, and biomedical research exist. A brief review of existing tracking technologies including a discussion of how their shortcomings are overcome by this system is included. Surface acoustic wave (SAW) device design and modeling is covered with particular attention paid to implementation of passive transponders. A method under development to fabricate SAW devices with features as small as 300nm is then covered in detail. The electronic design of the radar chirp transmitter and receiver are covered along with the design and implementation of the test electronics. Results from experiments conducted to characterize device performance are given. by Jason Michael LaPenta. S.M.
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Kondrath, Andrew Stephen. "Frequency Modulated Continuous Wave Radar and Video Fusion for Simultaneous Localization and Mapping." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1347715085.
Cheung, Sai-Kit. "The study of weak localization effects on wave dynamics in mesoscopic media in the diffusive regime and at the localization transition /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202006%20CHEUNG.
M, Soukoulis C., North Atlantic Treaty Organization. Scientific Affairs Division., and NATO Advanced Research Workshop on Localization and Propagation of Classical Waves in Random and Periodic Structures (1992 : Hagia Pelagia, Greece), eds. Photonic band gaps and localization. New York: Plenum Press, 1993.
NATO Advanced Research Workshop on Localization and Propagation of Classical Wavesin Random and Periodic Structures (1992 Aghia Pelaghia, Greece). Photonic band gaps and localization. New York: Plenum Press, 1993.
R, Champneys A., Hunt G. W. 1944-, and Thompson, J. M. T. 1937-, eds. Localization and solitary waves in solid mechanics. London: The Royal Society, 1997.
Berkovits, Richard, Lukas Jahnke, and Jan W. Kantelhardt. "Wave Localization on Complex Networks." In Towards an Information Theory of Complex Networks, 75–96. Boston, MA: Birkhäuser Boston, 2011. http://dx.doi.org/10.1007/978-0-8176-4904-3_4.
Cody, George, Ling Ye, Minyao Zhou, Ping Sheng, and Andrew N. Norris. "Experimental Observation of Bending Wave Localization." In Photonic Band Gaps and Localization, 339–53. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4899-1606-8_26.
Arya, Karamjeet. "Anderson Localization of the Electromagnetic Wave in a Random Dielectric Medium." In Wave Phenomena, 259–67. New York, NY: Springer New York, 1989. http://dx.doi.org/10.1007/978-1-4613-8856-2_17.
Leung, K. M. "Plane-Wave Calculation of Photonic Band Structure." In Photonic Band Gaps and Localization, 269–81. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4899-1606-8_20.
Turhan, Doğan, and Ibrahim A. Alshaikh. "Transient Wave Propagation in Periodically Layered Media." In Photonic Band Gaps and Localization, 479–85. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4899-1606-8_37.
Schreiber, M., and K. Maschke. "Scattering and Localization of Classical Waves Along a Wave Guide with Disorder and Dissipation." In Photonic Band Gaps and Localization, 439–51. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4899-1606-8_32.
Tip, A. "A Transport Equation for Random Electromagnetic Wave Propagation." In Photonic Band Gaps and Localization, 459–64. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4899-1606-8_34.
Kantelhardt, Jan W., Lukas Jahnke, and Richard Berkovits. "Wave Localization Transitions in Complex Systems." In Reviews of Nonlinear Dynamics and Complexity, 131–68. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2010. http://dx.doi.org/10.1002/9783527630967.ch5.
Klyatskin, Valery I. "Wave Localization in Randomly Layered Media." In Understanding Complex Systems, 59–93. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-56922-2_7.
ZHANG, YUANMAN, SHENGBO SHAN, and LI CHENG. "WAVE PROPAGATION AND DAMAGE LOCALIZATION IN THICK-WALLED HOLLOW CYLINDERS THROUGH INNER SENSING." In Structural Health Monitoring 2023. Destech Publications, Inc., 2023. http://dx.doi.org/10.12783/shm2023/36958.
Thick-walled hollow cylinders (TWHCs) are widely used in engineering structures and transportation systems, exemplified by train axles. The real-time and online health monitoring of such structures is crucial to ensure their structural integrity and operational safety. While elastic-wave-based structural health monitoring (SHM) shows promise, the development of feasible methods strongly relies on a good understanding and exploitation of the wave propagation properties and their interaction with structural defects. TWHCs usually bear multiple wave modes, which is a less investigated and explored topic as compared with thin-walled structures. This work examines this issue and proposes a dedicated damage localization strategy by using the selected waves captured on the inner surface of a TWHC. It is shown that, alongside the quasi-surface waves on the outer surface, longitudinal waves converted from the thickness-through shear bulk waves are generated to propagate along the inner surface. Their propagation characteristics are exploited for damage localization based on hyperbolic loci methods through inner surface sensing. Numerical studies are conducted to validate the method, alongside experimental verifications on a benchmark TWHC containing a notch-type defect. Studies provide guidance on damage detection in TWHCs and sensor network design.
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Sebbah, Patrick, Didier Sornette, and Christian Vanneste. "Wave Automaton for Wave Propagation in Random Media." In Advances in Optical Imaging and Photon Migration. Washington, D.C.: Optica Publishing Group, 2022. http://dx.doi.org/10.1364/aoipm.1994.wpl.68.
We present an original numerical approach for investigation of time-dependent wave propagation in random media. We review different results in 2D, including subdiffusive regime characterization, NDE in the multiple scattering regime and Anderson localization in presence of a nonlinear local gain.
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Barneto, Carlos Baquero, Taneli Riihonen, Matias Turunen, Mike Koivisto, Jukka Talvitie, and Mikko Valkama. "Radio-based Sensing and Indoor Mapping with Millimeter-Wave 5G NR Signals." In 2020 International Conference on Localization and GNSS (ICL-GNSS). IEEE, 2020. http://dx.doi.org/10.1109/icl-gnss49876.2020.9115568.
Kia, Ghazaleh, Laura Ruotsalainen, and Jukka Talvitie. "A CNN Approach for 5G mm Wave Positioning Using Beamformed CSI Measurements." In 2022 International Conference on Localization and GNSS (ICL-GNSS). IEEE, 2022. http://dx.doi.org/10.1109/icl-gnss54081.2022.9797028.
Carrara, M., M. R. Cacan, J. Toussaint, M. J. Leamy, M. Ruzzene, and A. Erturk. "Metamaterial Concepts for Structure-Borne Wave Energy Harvesting: Focusing, Funneling, and Localization." In ASME 2012 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/smasis2012-8166.
Enhancement of structure-borne wave energy harvesting is investigated by exploiting metamaterial-based and metamaterial-inspired electroelastic systems. The concepts of wave focusing, funneling, and localization are leveraged to establish novel Metamaterial–Energy Harvester (MEH) configurations. The MEH system transforms the incoming structure-borne wave energy into electrical energy by coupling the metamaterial and electroelastic domains. The energy harvesting component of the work employs piezoelectric transduction due to the high power density and ease of application offered by piezoelectric materials. Therefore, in all MEH configurations studied in this work, the metamaterial system is combined with piezoelectric energy harvesting for enhanced electricity generation from waves propagating in elastic structures. Experiments are conducted to validate the dramatic performance enhancement in MEH systems as compared to using the same volume of piezoelectric patch in the absence of the metamaterial component. It is shown that MEH systems can be used for both broadband and tuned wave energy harvesting. Examples include (1) wave guiding using an acoustic funnel, (2) wave focusing using a metamaterial-inspired elliptical acoustic mirror (both for broadband energy harvesting), and (3) energy localization using an imperfection in a 2-D lattice structure (for tuned energy harvesting).
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Li, Dong, and Haym Benaroya. "Wave localization in disordered periodic laminated materials." In 36th Structures, Structural Dynamics and Materials Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1995. http://dx.doi.org/10.2514/6.1995-1169.
Benassai, G., M. Dattero, and A. Maffucci. "Wave energy conversion systems: optimal localization procedure." In COASTAL PROCESSES 2009. Southampton, UK: WIT Press, 2009. http://dx.doi.org/10.2495/cp090121.
Photiadis, Douglas M. "Localization of Helical Flexural Waves on an Irregular Cylindrical Shell." In ASME 1993 Design Technical Conferences. American Society of Mechanical Engineers, 1993. http://dx.doi.org/10.1115/detc1993-0163.
Abstract Small amounts of irregularity are known to produce vibration localization in one-dimensional chains, but the effects on two and three dimensional systems are typically much weaker. We have considered a system with both one and two dimensional aspects, an axisymmetric, irregularly ribbed fluid-loaded cylindrical shell. A new formulation of this problem is given and each mode of the system is shown to be approximately equivilent to a nearest neighbor coupled chain with six degrees of freedom — corresponding to three left going and three right going traveling waves. Using these results all the azimuthal modes have been shown to be localized simultaneously and thus vibrational energy on an irregular cylindrical shell is Anderson localized. The slow flexural waves have been shown to localize separately from the fast waves provided the helical angle of the flexural wave is greater than about Ω1/25°, and for smaller helical angles, exponential localization is expected for distances less than a critical wave mixing length. Our results indicate that strong localization effects occur for the helical flexural waves yielding very short localization lengths of order a single rib spacing.
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Rahman, Lutfur, and Herbert G. Winful. "Fractal Transmission Properties of a Quasiperiodic Sequence of Directional Couplers." In Nonlinear Guided-Wave Phenomena. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/nlgwp.1989.fc3.
Quasi-periodic structures, structures which are intermediate between the periodic and disordered systems, have been a subject of considerable theoretical interest in recent years1–3. It has been shown theoretically that such structures display exotic behavior such as weak localization and scaling. Experimental realization of such structures and identification of these exotic features is needed. One potentially simple experiment towards this end has recently been proposed2 where a stack of dielectric layers is constructed using two types of dielectric layers arranged in a Fibonacci sequence. The transmission coefficient, as a function of the wavelength of incident light, was demonstrated to be multifractal and displayed scaling. Our work is concerned with a quasi-periodic optical system consisting of waveguide directional couplers which under certain resonant conditions displays localization and scaling. The energy exchange between the guides is codirectional as opposed to the contradirectional energy exchange of Ref. 2.
Звіти організацій з теми "Wave localization":
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Allen, S. J. High Electric Field Quantum Transport: Submillimeter Wave AC Stark Localization in Vertical and Lateral Superlattices. Fort Belvoir, VA: Defense Technical Information Center, March 1996. http://dx.doi.org/10.21236/ada313811.
Raghukumar, Kaustubha, Grace Chang, Frank Spada, Jesse Roberts, Jesse Spence, and Sharon Kramer. RAPIDLY DEPLOYABLE ACOUSTIC MONITORING AND LOCALIZATION SYSTEM BASED ON A LOW-COST WAVE BUOY PLATFORM. Office of Scientific and Technical Information (OSTI), March 2023. http://dx.doi.org/10.2172/1971138.
Rahmani, Mehran, Xintong Ji, and Sovann Reach Kiet. Damage Detection and Damage Localization in Bridges with Low-Density Instrumentations Using the Wave-Method: Application to a Shake-Table Tested Bridge. Mineta Transportation Institute, September 2022. http://dx.doi.org/10.31979/mti.2022.2033.
This study presents a major development to the wave method, a methodology used for structural identification and monitoring. The research team tested the method for use in structural damage detection and damage localization in bridges, the latter being a challenging task. The main goal was to assess capability of the improved method by applying it to a shake-table-tested prototype bridge with sparse instrumentation. The bridge was a 4-span reinforced concrete structure comprising two columns at each bent (6 columns total) and a flat slab. It was tested to failure using seven biaxial excitations at its base. Availability of a robust and verified method, which can work with sparse recording stations, can be valuable for detecting damage in bridges soon after an earthquake. The proposed method in this study includes estimating the shear (cS) and the longitudinal (cL) wave velocities by fitting an equivalent uniform Timoshenko beam model in impulse response functions of the recorded acceleration response. The identification algorithm is enhanced by adding the model’s damping ratio to the unknown parameters, as well as performing the identification for a range of initial values to avoid early convergence to a local minimum. Finally, the research team detect damage in the bridge columns by monitoring trends in the identified shear wave velocities from one damaging event to another. A comprehensive comparison between the reductions in shear wave velocities and the actual observed damages in the bridge columns is presented. The results revealed that the reduction of cS is generally consistent with the observed distribution and severity of damage during each biaxial motion. At bents 1 and 3, cS is consistently reduced with the progression of damage. The trends correctly detected the onset of damage at bent 1 during biaxial 3, and damage in bent 3 during biaxial 4. The most significant reduction was caused by the last two biaxial motions in bents 1 and 3, also consistent with the surveyed damage. In bent 2 (middle bent), the reduction trend in cS was relatively minor, correctly showing minor damage at this bent. Based on these findings, the team concluded that the enhanced wave method presented in this study was capable of detecting damage in the bridge and identifying the location of the most severe damage. The proposed methodology is a fast and inexpensive tool for real-time or near real-time damage detection and localization in similar bridges, especially those with sparsely deployed accelerometers.
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Sanchez, Darryl J., and Denis W. Oesch. The Localization of Angular Momentum in Optical Waves Propagating Through Turbulence. Fort Belvoir, VA: Defense Technical Information Center, October 2012. http://dx.doi.org/10.21236/ada580205.
Blevins, Matthew, Gregory Lyons, Carl Hart, and Michael White. Optical and acoustical measurement of ballistic noise signatures. Engineer Research and Development Center (U.S.), January 2021. http://dx.doi.org/10.21079/11681/39501.
Supersonic projectiles in air generate acoustical signatures that are fundamentally related to the projectile’s shape, size, and velocity. These characteristics influence various mechanisms involved in the generation, propagation, decay, and coalescence of acoustic waves. To understand the relationships between projectile shape, size, velocity, and the physical mechanisms involved, an experimental effort captured the acoustic field produced by a range of supersonic projectiles using both conventional pressure sensors and a schlieren imaging system. The results of this ongoing project will elucidate those fundamental mechanisms, enabling more sophisticated tools for detection, classification, localization, and tracking. This paper details the experimental setup, data collection, and preliminary analysis of a series of ballistic projectiles, both idealized and currently in use by the U.S. Military.
