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Potential of Global Positioning System (GPS) to measure frequencies of oscillations of engineering structures

Panos Psimoulis, Stella Pytharouli, Dimitris Karambalis, Stathis Stiros
2008 Journal of Sound and Vibration  
Data were processed using least squares-based spectral analysis and wavelet techniques which permit to analyze entire time series, even those of too short duration or those characterized by gaps, in both  ...  The ability of GPS to accurately measure frequencies of oscillations of relatively rigid (modal frequencies 1-4 Hz) civil engineering structures is demonstrated in the cases of two bridges.  ...  Acknowledgments This article is a contribution to the Research Project PENED-03ED53 of the Greek Secretariat of Research and Technology.  ... 
doi:10.1016/j.jsv.2008.04.036 fatcat:tkwivmnl3rg27npndavwrak4j4

Simplified transmission and generation system analysis procedures for subsynchronous resonance problems

L.A. Kilgore, D.G. Ramey, M.C. Hall
1977 IEEE Transactions on Power Apparatus and Systems  
This paper presents these relationships and uses them to derive a number of useful formulas for studying the problems.  ...  These formulas are most useful in planning a series capacitor compensated transmission system to avoid or minimize subsynchronous resonance problems, This application is the subject of a companion paper  ...  When the applied torque frequency is not one of the modal frequencies, this series of impulses is alternately in phase and out of phase with the oscillating response of the shaft.  ... 
doi:10.1109/t-pas.1977.32517 fatcat:a6azhh7mnbbmfkyhfdg3ojq3bu

Modelling of nonlinear modal interactions in the transient dynamics of an elastic rod with an essentially nonlinear attachment

S. Tsakirtzis, Y.S. Lee, A.F. Vakakis, L.A. Bergman, D.M. McFarland
2010 Communications in nonlinear science & numerical simulation  
The derived reduced order models (ROMs) are in the form of sets of uncoupled linear oscillators (termed intrinsic modal oscillators -IMOs), each corresponding to a basic frequency of the dynamical interaction  ...  and forced by transient excitations that represent the nonlinear modal interactions between the rod and the attachment at each of these basic frequencies.  ...  Acknowledgments This research was supported in part by the grant for basic research 'KARATHEODORI' awarded by the National Technical University of Athens, Greece, and by AFOSR Grant FA9550-07-1-0335.  ... 
doi:10.1016/j.cnsns.2009.10.014 fatcat:ussmxnufgvhk5p5wlcavv2yzmi

Effective Stiffening and Damping Enhancement of Structures With Strongly Nonlinear Local Attachments

Themistoklis P. Sapsis, D. Dane Quinn, Alexander F. Vakakis, Lawrence A. Bergman
2012 Journal of Vibration and Acoustics  
This feature, coupled with the well-established capacity of NESs to passively absorb and locally dissipate shock energy, can be used to create effective passive mitigation designs of structures under impulsive  ...  Three different applications are considered and show that these attachments can drastically increase the effective damping properties of a two-degrees-of-freedom system and, to a lesser degree, the stiffening  ...  The content of this paper does not necessarily reflect the position or the policy of the government, and no official endorsement should be inferred.  ... 
doi:10.1115/1.4005005 fatcat:ts53spw3dfemhdq3qpvpvhkyqu

Structure Dynamic Response of Amphibious Aircraft Induced by Water-Taxiing

Jihang Lyu, Rong Yang, Lingcai Huang, Giovanni Delibra
2021 International Journal of Aerospace Engineering  
Meanwhile, the modal characteristics of the structure are also affected by the additional motion of water.  ...  The significant dynamic response under the combined impact of aerodynamic and hydrodynamic forces could be likely to appear because of the structural flexibility, when taxiing on the water surface for  ...  Acknowledgments This paper is a part of a research project supported by the Department of R&D Centre and S&T Committee, AVIC General Huanan Aircraft Industry Limited Company. Thanks are due to Dr.  ... 
doi:10.1155/2021/6104407 fatcat:hr4g6qtom5av5agkxgxyuupqym

EXPERIMENTAL STUDY OF NON-LINEAR TRANSIENT MOTION CONFINEMENT IN A SYSTEM OF COUPLED BEAMS

J. Aubrecht, A.F. Vakakis, T.-C. Tsao, J. Bentsman
1996 Journal of Sound and Vibration  
It has been found that the system with active non-linearities possesses motion confinement properties, that is, transient motions originating at one of the beams become spatially confined mainly to the  ...  directly excited beam, with small amounts of vibrational energy "leaking" to the unexcited one.  ...  the existence of transient motion confinement due to nonlinear mode localization, an initial series of modal tests was performed.  ... 
doi:10.1006/jsvi.1996.0451 fatcat:cqrwkrgd7zb5lg7zibden2prwu

Analysis of stress wave propagation in composite rectangular beam in the case of ultrasonic pulse method

Toshiyuki OSHIMA, Shuichi MIKAMI, Sumio G. NOMACHI
1990 Doboku Gakkai Ronbunshu  
The transient response from the first incident wave through the whole oscillation of the beam is found by the series of simulation analysis.  ...  Making use of modal analysis and Duhamel integral equation, the impulse response of the composite rectangular beam is obtained.  ...  Formulating a couple of finite difference equations for a two-dimensional beam and analyzing ultrasonic response due to impulsive pulse by means of the modal analysis, we well find the process of transient  ... 
doi:10.2208/jscej.1990.416_89 fatcat:gduqmfxcdbgb7i2cgd4ziujsoe

Ultralow-frequency neural entrainment to pain

Yifei Guo, Rory John Bufacchi, Giacomo Novembre, Marina Kilintari, Massieh Moayedi, Li Hu, Gian Domenico Iannetti, David Poeppel
2020 PLoS Biology  
The non-supramodal nature of our results suggests that ultralow-frequency entrainment might be tuned to the temporal scale of the statistical regularities characteristic of different sensory modalities  ...  We show that ultralow-frequency neural oscillations preserved a long-lasting trace of sensory information through neural entrainment to periodic thermo-nociceptive input as low as 0.1 Hz.  ...  Thus, the power increase and phase locking of the EEG responses revealed by the following analyses were most likely due to a true 0.1-Hz oscillation rather than transient responses that repeated at this  ... 
doi:10.1371/journal.pbio.3000491 pmid:32282798 fatcat:nrn2cooveffi5k5aiafrfpnu2q

Analysis and Characterization of Power System Nonlinear Oscillations Using Hilbert Spectral Analysis

A.R. Messina, M.A. Andrade, J.H. Hernandez, R. Betancourt
2007 Open Electrical & Electronic Engineering Journal  
Using the notion of empirical mode decomposition, data from transient stability simulations is transformed into a series of mono-component signals.  ...  The method combines the Hilbert-Huang transform and concepts from vibrating systems theory and can be used to approximate the dynamic behavior of quasi-stationary oscillations.  ...  As stated in our general conclusions, the use of a low-dimensional representation greatly simplifies the analy-sis of the observed time series and allows us to concentrate on the dominant modal behavior  ... 
doi:10.2174/1874129000701010001 fatcat:hxl7752ozjfvng6vnspwnlc7wq

Effectiveness of TCSC controllers using remote input signals for transient stability enhancement

Nguyen Tuan Anh, D. Van Hertem, J. Driesen
2011 2011 IEEE Trondheim PowerTech  
This paper presents a method to improve the dynamic performance of a power system with Thyristor-Controlled Series Capacitor (TCSC) using remote measurement input signals.  ...  The case studies show the improvement of the transient stability comparing control using remote control signals instead of local signals.  ...  To analyze and compare the controlling effects of the TCSCs for the transient stability enhancement along with the different input signals, the simulations of the rotor angle oscillations involve three  ... 
doi:10.1109/ptc.2011.6019435 fatcat:shz6ehvbgbb4pldyrkvzvusfui

A decoupled modal analysis for nonlinear dynamics of an orthotropic thin laminate in a simply supported boundary condition subject to thermal mechanical loading

Xiaoling He
2006 International Journal of Solids and Structures  
In this paper, we analyze the nonlinear dynamic response of an orthotropic laminate in a simply supported boundary condition subject to thermal and mechanical loading.  ...  The equation allows for characterization of the laminate behaviors in nonlinear thermal buckling, thermal vibration and thermal mechanical response.  ...  Acknowledgement The author expresses deep gratitude to the late Professor Fulton for his support and guidance in the early stage of her research.  ... 
doi:10.1016/j.ijsolstr.2006.03.017 fatcat:mrhbhf7wvvhtvbhmhtmd5ulsiy

Ultra-low frequency neural entrainment to pain [article]

Yifei Guo, Rory John Bufacchi, Giacomo Novembre, Marina Kilintari, Massieh Moayedi, Li Hu, Giandomenico Iannetti
2019 bioRxiv   pre-print
The non-supramodal nature of our results suggests that ultra-low frequency entrainment might be tuned to the temporal scale of the statistical regularities characteristic of different sensory modalities  ...  We show that ultra-low frequency neural oscillations preserved a long-lasting trace of sensory information through neural entrainment to periodic thermo-nociceptive input as low as 0.1 Hz.  ...  transient responses.  ... 
doi:10.1101/759233 fatcat:d3te45xowngndixytgnrwktcpm

Simulation of Single Reed Instruments Oscillations Based on Modal Decomposition of Bore and Reed Dynamics [article]

Fabrice Silva , Christophe Vergez
2007 arXiv   pre-print
The airrrflow blown into the bore is modulated by reed motion, assuming the reed to be a single degree of freedom oscillator.  ...  Extending previous work (Debut, 2004), the input impedance of the bore is projected on the modes of the air column. The acoustic pressure is therefore calculated as the sum of modal components.  ...  Acknowledgments The study presented in this paper was lead with the support of the French National Research Agency ANR within the CONSONNES project.  ... 
arXiv:0705.2803v1 fatcat:mdjkmim2jzbv3li3xugflyq7py

Inclusion of Higher Order Terms for Small-Signal (Modal) Analysis: Committee Report—Task Force on Assessing the Need to Include Higher Order Terms for Small-Signal (Modal) Analysis

J.J. Sanchez-Gasca, V. Vittal, M.J. Gibbard, A.R. Messina, D.J. Vowles, S. Liu, U.D. Annakkage
2005 IEEE Transactions on Power Systems  
The focus of the work reported here is on establishing and documenting the practical significance of these terms in stability analysis using the method of Normal Forms.  ...  The use of the higher order terms in the site selection for a damping controller is also documented.  ...  The case is studied using linear (conventional) and nonlinear modal analyzes techniques to determine suitable locations for controllers to damp the inter area mode of oscillation.  ... 
doi:10.1109/tpwrs.2005.858029 fatcat:uh7tuiihcjfplobnelguwx6ete

Neoclassical Solution of Transient Interaction of Plane Acoustic Waves with a Spherical Elastic Shell

Hanson Huang, Hans U. Mair
1996 Shock and Vibration  
eradicating spurious oscillations due to the Gibbs' phenomenon.  ...  Together with the application of the Cesaro summation using up to 70 terms of the series, two primary deficiencies of the previous solution are now remedied: meaningful time histories of higher time derivative  ...  The authors also wish to express their appreciation to Professor Thomas L. Geers of the University of Colorado for his critical discussions.  ... 
doi:10.1155/1996/387364 fatcat:xahyle4r25gejju7aenyep7fdm
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