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Journal articles on the topic 'Time Varying Harmonic Analyzer'

Author: Grafiati

Published: 4 June 2021

Last updated: 4 February 2022

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1

Belchior, Fernando Nunes, Paulo Fernando Ribeiro, and Frederico Marques Carvalho. "Comparative Analysis of Instruments Measuring Time Varying Harmonics." International Journal of Emerging Electric Power Systems 17, no. 4 (2016): 463–69. http://dx.doi.org/10.1515/ijeeps-2015-0175.

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Abstract This paper aims to evaluate the performance of commercial class A and class S power quality (PQ) instruments when measuring time-varying harmonics. By using a high precision programmable voltage and current source, two meters from different manufacturers are analyzed and compared. Three-phase voltage signals are applied to PQ instruments, considering 3 situations of time-varying harmonic distortions, whose harmonic distortion values are in accordance with typical values found in power systems. This work is relevant considering that international standardization documents do not pay mu

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2

ZHANG, WEI, and QIAN DING. "TORSION VIBRATION AND PARAMETRIC INSTABILITY ANALYSIS OF A SPUR GEAR SYSTEM WITH TIME-VARYING AND SQUARE NONLINEARITIES." International Journal of Applied Mechanics 06, no. 01 (2014): 1450007. http://dx.doi.org/10.1142/s1758825114500070.

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This paper investigates the dynamics of a spur gear system with time-varying and square nonlinearities, by both analytical method and numerical simulation. First, the equations of motion of a 2 degree-of-freedom system are established and the harmonic balance method is used to analyze the stability and the steady-state response of the system under the main resonant condition. Then the perturbation method is used to analyze the parameter instability under the main, subharmonic and nonresonance conditions. Finally, the interactions between the main and subharmonic resonant amplitudes and the non

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3

Seferi, Yljon, Steven M. Blair, Christian Mester, and Brian G. Stewart. "Power Quality Measurement and Active Harmonic Power in 25 kV 50 Hz AC Railway Systems." Energies 13, no. 21 (2020): 5698. http://dx.doi.org/10.3390/en13215698.

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Railway electrical networks rated at 25 kV 50 Hz are characterised by significant levels of voltage and current harmonics. These frequency components are also time varying in nature due to the movement of trains and changing operational modes. Processing techniques used to evaluate harmonic results, although standardised, are not explicitly designed for railway applications, and the smoothing effect that the standard aggregation algorithms have on the measured results is significant. This paper analyses the application accuracy of standardised power quality (PQ) measurement algorithms, when us

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Avirajamanjula, P., and P. Palanivel. "Corroboration of Normalized Least Mean Square Based Adaptive Selective Current Harmonic Elimination in Voltage Source Inverter using DSP Processor." International Journal of Power Electronics and Drive Systems (IJPEDS) 6, no. 1 (2015): 178. http://dx.doi.org/10.11591/ijpeds.v6.i1.pp178-184.

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A direct Selective current harmonic elimination pulse width modulation technique is proposed for induction motor drive fed from voltage source inverter. The developed adaptive filtering algorithm for the selective current harmonic elimination in a three phase Voltage Source Inverter is a direct method to improve the line current quality of the Voltage Source Inverter base drive at any load condition. The self-adaptive algorithm employed has the capability of managing the time varying nature of load (current). The proposed Normalized Least Mean Squares algorithm based scheme eliminates the sele

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Qiu, Huan Song, Jie Hong Yuan, Yuan Li, and Xing Li. "Dynamic Analysis of Spiral Bevel Gear Pair under Time-Varying Backlash." Advanced Materials Research 940 (June 2014): 217–21. http://dx.doi.org/10.4028/www.scientific.net/amr.940.217.

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Neglecting the influence of static transmission error, a non-linear dynamic model of spiral bevel gear pair with time-varying backlash was presented. Through the simplification of above model, the dimensionless form of gear system was obtained. Then, the dynamic characteristics of gear system were acquired by using Runge-Kutta method under the influence of time-varying backlash and torque. The results showed primary harmonic amplitude of gear backlash and torque had a significant effect on the non-linear and vibration characteristics of gear system. With the change of that, bifurcation phenome

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Liang, Qing Yang, Zhe Sun, and Chen Fei Zhang. "Method of Harmonic Detection Based on the Wavelet Transform." Advanced Materials Research 748 (August 2013): 646–50. http://dx.doi.org/10.4028/www.scientific.net/amr.748.646.

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The harmonic current detection technology is one of the key technologies of active power filter technologies. The development of the harmonic current detection technology directly determines the development of the active power filter technologies. Based on this, this paper introduces some basis concepts of wavelet transform and analyzes its time-frequency localization properties, then, describes the harmonic detection methods based on wavelet transform in terms of program building, algorithm selection and wavelet function selection. The results show that the harmonic current detection methods

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Rangelov, Tsviatko, Marin Marinov, and Petia Dineva. "TIME–HARMONIC BEHAVIOUR OF CRACKED PIEZOELECTRIC SOLID BY BOUNDARY INTEGRAL EQUATION METHOD." Journal of Theoretical and Applied Mechanics 44, no. 1 (2014): 55–78. http://dx.doi.org/10.2478/jtam-2014-0004.

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Abstract Anti-plane cracked functionally graded finite piezoelectric solid under time-harmonic elecromechanical load is studied by a non-hypersingular traction boundary integral equation method (BIEM). Exponentially varying material properties are considered. Numerical solutions are obtained by using Mathematica. The dependance of the intensity factors (IF) - mechanical stress intensity factor (SIF) and electrical field intensity factor (FIF) on the inhomogeneous material parameters, on the type and frequency of the dynamic load and on the crack position are analyzed by numerical illustrative

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8

Singh, Amarjeet. "Comparative Analysis of Different Models of Electric Arc Furnace." SAMRIDDHI : A Journal of Physical Sciences, Engineering and Technology 10, no. 02 (2018): 99–106. http://dx.doi.org/10.18090/samriddhi.v10i02.4.

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The nonlinear and time varying nature of Electric Arc Furnace (EAF) causes power quality problems such as harmonics, flicker and voltage /current imbalances. In order to analyze the power quality of power system containing EAF, mathematical model of arc furnace becomes useful and informative. This paper presents different models of alternating current operated arc furnace to analyze the power quality in electric power system. The behavior of these models under static and dynamic conditions is studied. A comparison is also made between these models of arc furnace. Simulation results in MATLAB/

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9

Dong, Hao, Libang Wang, Haoqin Zhang, and Xiao-long Zhao. "Nonlinear Frequency Response Analysis of Double-helical Gear Pair Based on the Incremental Harmonic Balance Method." Shock and Vibration 2021 (April 15, 2021): 1–20. http://dx.doi.org/10.1155/2021/6687467.

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The torsional dynamic model of double-helical gear pair considering time-varying meshing stiffness, constant backlash, dynamic backlash, static transmission error, and external dynamic excitation was established. The frequency response characteristics of the system under constant and dynamic backlashes were solved by the incremental harmonic balance method, and the results were further verified by the numerical integration method. At the same time, the influence of time-varying meshing stiffness, damping, static transmission error, and external load excitation on the amplitude frequency charac

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10

Yang, Yi, Mengjuan Xu, Yang Du, Pan Zhao, and Yiping Dai. "Dynamic analysis of nonlinear time-varying spur gear system subjected to multi-frequency excitation." Journal of Vibration and Control 25, no. 6 (2018): 1210–26. http://dx.doi.org/10.1177/1077546318814951.

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Due to the complex working environment, gear systems always suffer from multiple excitations in actual engineering. This paper concerns the frequency response characteristics of a nonlinear time-varying spur gear system subjected to multi-frequency excitation. Firstly, a single degree-of-freedom gear pair model is established with consideration of the gear backlash, time-varying mesh stiffness and multiple harmonic excitations. Then, using the multiple time scales method, a comprehensive theoretical study is conducted to analyze various resonant cases including primary, parametric and combinat

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Othman, Mohamed I. A., and Ahmed E. Abouelregal. "Magnetothermoelastic interactions in non-simple medium with a spherical cavity due to time-harmonic varying heat." Multidiscipline Modeling in Materials and Structures 15, no. 5 (2019): 932–46. http://dx.doi.org/10.1108/mmms-05-2018-0098.

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Purpose The purpose of this paper is to investigate the dynamic response for a thermoelastic infinite medium with a spherical cavity in the context of the theory of two-temperature thermoelasticity without energy dissipation. Design/methodology/approach The cavity is fixed and subjected to a subjected to harmonically varying temperature. Findings The exact expressions for displacement, temperature and thermal stresses are computed and represented graphically. These distributions are calculated for a copper material and results are analyzed. Originality/value Effects of non-simple heat conducti

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12

HØYE, JOHAN S., and IVER BREVIK. "CASIMIR FRICTION FORCE FOR MOVING HARMONIC OSCILLATORS." International Journal of Modern Physics A 27, no. 15 (2012): 1260011. http://dx.doi.org/10.1142/s0217751x12600111.

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Casimir friction is analyzed for a pair of dielectric particles in relative motion. We first adopt a microscopic model for harmonically oscillating particles at finite temperature T moving nonrelativistically with constant velocity. We use a statistical-mechanical description where time-dependent correlations are involved. This description is physical and direct, and, in spite of its simplicity, is able to elucidate the essentials of the problem. This treatment elaborates upon, and extends, an earlier theory of ours back in 1992. The energy change ΔE turns out to be finite in general, correspo

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HØYE, JOHAN S., and IVER BREVIK. "CASIMIR FRICTION FORCE FOR MOVING HARMONIC OSCILLATORS." International Journal of Modern Physics: Conference Series 14 (January 2012): 141–54. http://dx.doi.org/10.1142/s2010194512007295.

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Casimir friction is analyzed for a pair of dielectric particles in relative motion. We first adopt a microscopic model for harmonically oscillating particles at finite temperature T moving non-relativistically with constant velocity. We use a statistical-mechanical description where time-dependent correlations are involved. This description is physical and direct, and, in spite of its simplicity, is able to elucidate the essentials of the problem. This treatment elaborates upon, and extends, an earlier theory of ours back in 1992. The energy change ΔE turns out to be finite in general, corresp

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14

Han, Aoxue, Colm Dineen, Viktoriia E. Babicheva, and Jerome V. Moloney. "Second harmonic generation in metasurfaces with multipole resonant coupling." Nanophotonics 9, no. 11 (2020): 3545–56. http://dx.doi.org/10.1515/nanoph-2020-0193.

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AbstractWe report on the numerical demonstration of enhanced second harmonic generation (SHG) originating from collective resonances in plasmonic nanoparticle arrays. The nonlinear optical response of the metal nanoparticles is modeled by employing a hydrodynamic nonlinear Drude model implemented into Finite-Difference Time-Domain (FDTD) simulations, and effective polarizabilities of nanoparticle multipoles in the lattice are analytically calculated at the fundamental wavelength by using a coupled dipole–quadrupole approximation. Excitation of narrow collective resonances in nanoparticle array

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15

Yang, Jianxiang, Anle Mu, and Nailu Li. "Dynamical Analysis and Stabilization of Wind Turbine Drivetrain via Adaptive Fixed-Time Terminal Sliding Mode Controller." Mathematical Problems in Engineering 2019 (July 22, 2019): 1–14. http://dx.doi.org/10.1155/2019/8982028.

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In order to study the stability of the wind turbine drivetrain in further depth, we present a nonlinear relative rotation mathematical model considering the nonlinear time-varying stiffness and the nonlinear damping force. Meanwhile, the nonlinear dynamics of the model under combined harmonic excitation are studied in detail. And some interesting dynamic phenomena are observed visually. Furthermore, to suppress chaotic oscillation within bounded time independent of initial conditions, a novel adaptive fixed-time terminal sliding mode controller is proposed. The stability of the final closed lo

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16

Khuleedee, Weerachat, Arkom Kaewrawang, and Kittipong Tonmitr. "Impact of On-Grids Solar PV Rooftop on Low Voltage Grid Systems: A Case Study of PEA Udonthani, Thailand." Applied Mechanics and Materials 781 (August 2015): 296–99. http://dx.doi.org/10.4028/www.scientific.net/amm.781.296.

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This paper presents the impact of on-grid solar PV rooftop on local power systems of 10 kW - typical low voltage power rating for households campaigned by Thai Government. The overvoltage, frequency variation and harmonic contamination was investigated and analyzed. The condition of peak power generated from PV was also considered. The experimental data used for the analysis were collected by turning on and off the solar PV system of PEA power system on Udonthani province, Thailand for every hour with duration time between 6.00 AM and 6.00 PM. The results showed that the voltage at the connect

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17

Morgan, R. A., and K. W. Wang. "An Active-Passive Piezoelectric Absorber for Structural Vibration Control Under Harmonic Excitations With Time-Varying Frequency, Part 1: Algorithm Development and Analysis." Journal of Vibration and Acoustics 124, no. 1 (2001): 77–83. http://dx.doi.org/10.1115/1.1419201.

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It has been shown that piezoelectric materials can be used as passive electromechanical vibration absorbers by shunting them with electrical networks. Semi-active piezoelectric absorbers have also been proposed for suppressing harmonic excitations with varying frequency. However, these semi-active devices have limitations that restrict their practical applications. The approach presented here is a high performance active-passive alternative to semi-active absorbers. By utilizing a combination of a passive electrical circuit and active control actions, the system is synthesized for adaptive var

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18

Zheng, Yu Qi, Xiang Zhen Xue, and San Min Wang. "Research on the Dynamic Response of a Combining Gear Drive System." Applied Mechanics and Materials 86 (August 2011): 86–89. http://dx.doi.org/10.4028/www.scientific.net/amm.86.86.

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Gear dynamics model and 16-degree of freedom nonlinear vibration equations of the combining gear drive system are established considering backlash, transmission error and time-varying mesh stiffness, the equations are solved thanks to the fourth-order Runge-Kutta method, and the gear dynamic responses are analyzed, the vibration performances of this system affected by the dimensionless vibration frequency are investigated. The results show when the dimensionless frequency is 0.687, the system appears harmonic response; when the dimensionless frequency is 0.868, the system appears quasi-periodi

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19

Zheng, Yang, Zi Rong Luo, Jian Zhong Shang, Xiao Ming Wang, and Nai Hui Yu. "Dynamics Modeling and Resonance Analysis of Anti-Backlash Gear Transmission System Based on Harmonic Balance Method." Advanced Materials Research 711 (June 2013): 556–61. http://dx.doi.org/10.4028/www.scientific.net/amr.711.556.

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Anti-backlash gear system is applied widely in precision mechanisms, and it is important to research its dynamic characteristics for improving the dynamic accuracy of system. The nonlinear dynamics equivalent model of an anti-backlash gear system in a servomechanism with time-varying mesh stiffness and gear side clearance is proposed. The dynamic transmission error of system is calculated by HBM and numerical computation method (NCM). Based on this, the effect of different parameters on resonance frequency of system is analyzed deeply. The results show that the resonance frequency is higher, w

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20

Zhang, Zhiyong, Thomas Sattel, Yujie Zhu, Xuan Li, Yawei Dong, and Xiaoting Rui. "Mechanism and Characteristics of Global Varying Compliance Parametric Resonances in a Ball Bearing." Applied Sciences 10, no. 21 (2020): 7849. http://dx.doi.org/10.3390/app10217849.

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Varying compliance (VC) is an unavoidable form of parametric excitation in rolling bearings and can affect the stability and safety of the bearing and its supporting rotor system. To date, we have investigated VC primary resonance in ball bearings, and in this paper other parametric VC resonance types are addressed. For a classical ball bearing model with Hertzian contact and clearance nonlinearities between the rolling elements and raceway, the harmonic balance and alternating frequency/time domain (HB–AFT) method and Floquet theory are adopted to analyze the VC parametric resonances and thei

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21

Abouelregal, Ahmed E., Hijaz Ahmad, Taher A. Nofal, and Hanaa Abu-Zinadah. "Thermo-viscoelastic fractional model of rotating nanobeams with variable thermal conductivity due to mechanical and thermal loads." Modern Physics Letters B 35, no. 18 (2021): 2150297. http://dx.doi.org/10.1142/s0217984921502973.

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This paper analyzes the thermoelastic dynamic behavior of simply supported viscoelastic nanobeams of fractional derivative type due to a dynamic strength load. The viscoelastic Kelvin–Voigt model with fractional derivative with Bernoulli–Euler beam theory is introduced. The generalized thermoelastic heat conduction model with a two-phase lag is also used. It is assumed that the beam is rotating at a uniform angular velocity and that the thermal conductivity varies linearly depending on the temperature. Due to a variable harmonic heat and retreating time-dependent load, the nanobeam is excited.

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22

Venkat, N. K., and M. Spaulding. "Influence of Vibration Amplitude on Laminar Flow Over a Plate Vibrating at Low Strouhal Number." Journal of Fluids Engineering 115, no. 3 (1993): 411–19. http://dx.doi.org/10.1115/1.2910154.

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The spectral and hydrodynamic response of laminar flow over a flat plate with a vibrating section forced in sinusoidal motion with a dimensionless amplitude ratio, H0 (vibration amplitude divided by plate length) varying in the range 0.0 < H0 < 0.1 is analyzed using numerical simulations. The Reynolds number, Re, based on the length of the vibrating plate, is fixed at 1000. The flow is simulated for Strouhal number, St, = 0.25 (low frequency). The spectral characteristics are obtained by performing Fast Fourier Transform (FFT) on the pressure coefficient time series data. The hydrodynami

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Hou, Jingyu, Shaopu Yang, Qiang Li, and Yongqiang Liu. "Nonlinear dynamic analysis of spur gear system based on fractional-order calculus." Modern Physics Letters B 34, no. 36 (2020): 2050420. http://dx.doi.org/10.1142/s0217984920504205.

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In this paper, nonlinear dynamic model of spur gear pairs with fractional-order damping under the condition of time-varying stiffness, backlash and static transmission error is established. The general formula of fractional-order damping term is derived by using the incremental harmonic balance method (IHBM), and the approximate analytical solution of the system is obtained by use of the iterative formula. The correctness of the results is verified by comparing with the numerical solutions in the existing literature. The effects of mesh stiffness, internal excitation amplitude and fractional o

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Venkat, N. Kolluru, and Malcolm Spaulding. "A Numerical Model to Predict the Nonlinear Response of External Flow Over Vibrating Bodies (Planar Flow)." Journal of Fluids Engineering 113, no. 4 (1991): 544–54. http://dx.doi.org/10.1115/1.2926513.

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A model is developed to simulate two-dimensional laminar flow over an arbitrarily shaped body, a portion of which is subjected to time varying harmonic motion. The model is tested by comparison to previous numerical simulations for flow over a square cavity, oscillatory flow through a wavy channel and boundary layer flow along a flat plate. The model is applied to predict the flow over a flat plate with a section forced in simple sinusoidal motion. The dimensionless vibration amplitude, H0, and the Reynolds number, Re are maintained at 0.1 and 1000, respectively. The Strouhal number, St, defin

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25

Liu, Dawei, Zhenzhen Lv, and Guohao Zhao. "Rattle dynamics of noncircular face gear under multifrequency parametric excitation." Mechanical Sciences 12, no. 1 (2021): 361–73. http://dx.doi.org/10.5194/ms-12-361-2021.

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Abstract. A noncircular face gear (NFG) conjugated with a pinion is a new type of face gear which can transmit variable velocity ratio and in which two time-varying excitations exist, namely the meshing stiffness excitation and instantaneous center excitation. Considering the tooth backlash, static transmission error and multifrequency parametric excitation, a nonlinear dynamic model of the NFG pair is presented. Based on the harmonic balance method and discrete Fourier transformation, a semi-analytic approach for the nonlinear dynamic model is given to analyze the dynamic behaviors of the NFG

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Raupp, Carlos F. M., and Pedro L. Silva Dias. "Resonant Wave Interactions in the Presence of a Diurnally Varying Heat Source." Journal of the Atmospheric Sciences 66, no. 10 (2009): 3165–83. http://dx.doi.org/10.1175/2009jas2899.1.

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Abstract Resonant interactions among equatorial waves in the presence of a diurnally varying heat source are studied in the context of the diabatic version of the equatorial β-plane primitive equations for a motionless, hydrostatic, horizontally homogeneous and stably stratified background atmosphere. The heat source is assumed to be periodic in time and of small amplitude [i.e., O(ɛ)] and is prescribed to roughly represent the typical heating associated with deep convection in the tropical atmosphere. In this context, using the asymptotic method of multiple time scales, the free linear Rossby

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27

Mitra, RK, S. Chatterjee, and AK Banik. "Limit cycle oscillation and multiple entrainment phenomena in a duffing oscillator under time-delayed displacement feedback." Journal of Vibration and Control 23, no. 17 (2015): 2742–56. http://dx.doi.org/10.1177/1077546315621214.

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The Duffing oscillator under time-delayed displacement feedback is investigated to study the effect of intentional time-delay on the global dynamics of the oscillator. From the free vibration study performed by employing the describing function method it is observed that for the undamped oscillator, an infinite number of limit cycles is present for all possible values of gain and delay. The number of stable and unstable limit cycles in the gain versus delay plane is studied region wise with the help of limit cycle stability lines. Secondly, in a damped system, the number of limit cycles is fin

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28

Yun, Jong-Il, Reinhardt Klenze, and Jae-Il Kim. "Laser-Induced Breakdown Spectroscopy for the On-Line Multielement Analysis of Highly Radioactive Glass Melt Simulants. Part II: Analyses of Molten Glass Samples." Applied Spectroscopy 56, no. 7 (2002): 852–58. http://dx.doi.org/10.1366/000370202760171518.

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The paper presents the application of laser-induced breakdown spectroscopy (LIBS) for the on-line multielement analyses of glass melts in a vitrification process of high level liquid waste (HLLW). The third harmonic pulse of an Nd:YAG laser is used for the generation of plasma on the molten glass surface and the plasma emission is monitored by an echelle spectrometer with an intensified charge-coupled device (ICCD), which simultaneously covers the wavelength range from 200 to 780 nm. Twelve different reference HLLW glass melts with a complex composition of about 27 chemical elements are simula

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29

Raupp, Carlos F. M., André S. W. Teruya, and Pedro L. Silva Dias. "Linear and Weakly Nonlinear Energetics of Global Nonhydrostatic Normal Modes." Journal of the Atmospheric Sciences 76, no. 12 (2019): 3831–46. http://dx.doi.org/10.1175/jas-d-19-0131.1.

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Abstract Here the theory of global nonhydrostatic normal modes has been further developed with the analysis of both linear and weakly nonlinear energetics of inertia–acoustic (IA) and inertia–gravity (IG) modes. These energetics are analyzed in the context of a shallow global nonhydrostatic model governing finite-amplitude perturbations around a resting, hydrostatic, and isothermal background state. For the linear case, the energy as a function of the zonal wavenumber of the IA and IG modes is analyzed, and the nonhydrostatic effect of vertical acceleration on the IG waves is highlighted. For

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Liu, Yizhe, Bofang Zhang, Ting Wang, Tian Su та Hanyang Chen. "Dynamic analysis of multilayer-reinforced concrete frame structures based on NewMark-β method". REVIEWS ON ADVANCED MATERIALS SCIENCE 60, № 1 (2021): 567–77. http://dx.doi.org/10.1515/rams-2021-0042.

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Abstract The analysis method of the simplified structure formation model provides the basis for the analysis of the reinforced concrete (RC) structure under earthquake and dynamic load, which has important significance for seismic analysis of RC structure. In this paper, the three-layer RC frame structure is simulated and analyzed by MATLAB based on the NewMark-β method, considering the influence of time-varying simple harmonic loads and seismic waves on acceleration, displacement, and velocity of RC structure. The vibration response of the RC structure is analyzed by introducing the stiffness

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Wang, Xigui, Siyuan An, Yongmei Wang, Jiafu Ruan, and Baixue Fu. "Semi-numerical analysis of a two-stage series composite planetary transmission considering incremental harmonic balance and multi-scale perturbation methods." Mechanical Sciences 12, no. 2 (2021): 701–14. http://dx.doi.org/10.5194/ms-12-701-2021.

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Abstract. This study conducts an analytical investigation of the dynamic response characteristics of a two-stage series composite system (TsSCS) with a planetary transmission consisting of dual-power branches. An improved incremental harmonic balance (IHB) method, which solves the closed solution of incremental parameters passing through the singularity point of the analytical path, based on the arc length extension technique, is proposed. The results are compared with those of the numerical integration method to verify the feasibility and effectiveness of the improved method. Following that,

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Forootan, Ehsan, Saeed Farzaneh, Kowsar Naderi, and Jens Peter Cederholm. "Analyzing GNSS Measurements to Detect and Predict Bridge Movements Using the Kalman Filter (KF) and Neural Network (NN) Techniques." Geomatics 1, no. 1 (2021): 65–80. http://dx.doi.org/10.3390/geomatics1010006.

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In this study, we present a data processing framework to apply measurements of the Global Navigation Satellite System (GNSS) technique for analyzing and predicting the movements of civil structures such as bridges. The proposed approach reduces the noise level of GNSS measurements using the Kalman Filter (KF) approach and enables the estimation of static, semi-static, and dynamic components of the bridge’s movements using a series of analyses such as the temporal filtering and the Least Squares Harmonic Estimation (LS-HE). The numerical results indicate that by using a RTK-GNSS system the semi

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Zapoměl, Jaroslav, Vladimír Dekýš, Petr Ferfecki, Alžbeta Sapietová, Milan Sága, and Milan Žmindák. "Identification of Material Damping of a Carbon Composite Bar and Study of Its Effect on Attenuation of Its Transient Lateral Vibrations." International Journal of Applied Mechanics 07, no. 06 (2015): 1550081. http://dx.doi.org/10.1142/s1758825115500817.

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Reduction of noise and vibrations is one of the major requirements put on operation of modern machines. It can be achieved by application of new materials. The ability to utilize them properly requires learning more about their mechanical properties. Vibration attenuation depends on material damping as an important factor. This paper presents the results of research in a carbon composite material focusing on its internal damping, on the measurement of the damping coefficients and on its implementation into mathematical models. The obtained results were used for investigation of suppressing lat

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Placet, Vincent, Joëlle Passard, and Patrick Perré. "Viscoelastic properties of green wood across the grain measured by harmonic tests in the range 0–95°C: Hardwood vs. softwood and normal wood vs. reaction wood." Holzforschung 61, no. 5 (2007): 548–57. http://dx.doi.org/10.1515/hf.2007.093.

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Abstract The viscoelastic properties of wood have been investigated with a dynamic mechanical analyser specifically developed for wooden materials, the WAVET device. Measurements were carried out on four wood species in the temperature range 0–100°C at frequencies varying between 5 mHz and 10 Hz. Wood samples were tested under water-saturated conditions in the radial and tangential directions. As expected, the radial direction always revealed a higher storage modulus than the tangential direction. Great differences were also observed in the loss factor. The tanδ peak and internal friction were

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Berbyuk, Viktor. "Design Optimization of Torsional Vibration Absorbers for Heavy-Duty Truck Drivetrain Systems." Vibration 2, no. 3 (2019): 240–64. http://dx.doi.org/10.3390/vibration2030015.

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In this paper, the feasibility of the application of a dual mass flywheel (DMF) for heavy-duty truck drivetrain systems was studied. The third engine order vibration harmonic was in the focus of analysis as one of the most significant contributions to the oscillatory response in the drivetrain systems of heavy-duty trucks. Global sensitivity analysis (GSA) and Pareto optimization were used for designing torsional vibration absorbers in an operating engine speed range of 600–2000 rpm. The optimization method attempted both to minimize the oscillations of the torque at the transmission input sha

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Bulycheva, Evgeniia, and Sergey Yanchenko. "Real-time harmonic identification under varying grid conditions." Serbian Journal of Electrical Engineering 18, no. 1 (2021): 29–48. http://dx.doi.org/10.2298/sjee2101029b.

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One of the challenges of the power quality management is a need for reliable harmonic identification in grids with multiple non-linear loads. This paper proposes a novel method to accurately determine time-varying harmonic contributions of non-linear loads to the total grid voltage distortion. The use of the invasive measurement approach and ternary pulse sequence as a stimuli guarantees an accurate assessment of harmonic contribution with the account for timevariating harmonic impacts. The application of proposed approach is demonstrated by means of time-domain grid simulation with implemente

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Zhou, Jianxing, Wenlei Sun, and Li Cao. "Vibration and noise characteristics of a gear reducer under different operation conditions." Journal of Low Frequency Noise, Vibration and Active Control 38, no. 2 (2019): 574–91. http://dx.doi.org/10.1177/1461348419825603.

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Gear system is characterized by high efficiency, compact structure, and transmission ratio stability, and it has been extensively applied in various industrial equipment. This paper presents a novel preliminary estimate method for gear reducer noise radiation and vibration characteristics, and systematic researches on radiation characteristics of gear reducer are made. In the noise analysis process, the influence of time-varying mesh stiffness, error excitation, and tooth flank contact feature are comprehensively considered, the linear vibration model and nonlinear vibro-impact model for trans

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Baghzouz, Y., R. F. Burch, A. Capasso, et al. "Time-varying harmonics. II. Harmonic summation and propagation." IEEE Transactions on Power Delivery 17, no. 1 (2002): 279–85. http://dx.doi.org/10.1109/61.974219.

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Vogt, T., M. Schirmer, and O. A. Cirpka. "Heat transport of diurnal temperature oscillations upon river-water infiltration investigated by fiber-optic high-resolution temperature profiling." Hydrology and Earth System Sciences Discussions 8, no. 3 (2011): 6257–89. http://dx.doi.org/10.5194/hessd-8-6257-2011.

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Abstract. River-water infiltration is of high relevance for hyporheic and riparian groundwater ecology as well as for drinking water supply by river-bank filtration. Heat has become a popular natural tracer to estimate exchange rates between rivers and groundwater. However, quantifying flow patterns and velocities is impeded by spatial and temporal variations of exchange fluxes, insufficient sensors spacing during field investigations, or simplifying assumptions for analysis or modeling such as uniform flow. The objective of this study is to investigate local heat transport upon river-water in

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Cheng, Yuping, and Teik C. Lim. "Dynamics of Hypoid Gear Transmission With Nonlinear Time-Varying Mesh Characteristics." Journal of Mechanical Design 125, no. 2 (2003): 373–82. http://dx.doi.org/10.1115/1.1564064.

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The coupled translation-rotation vibratory response of hypoid geared rotor system due to loaded transmission error excitation is studied by employing a generalized 3-dimensional dynamic model. The formulation includes the effects of backlash nonlinearity as well as time-dependent mesh position and line-of-action vectors. Its mesh coupling is derived from a quasi-static, 3-dimensional, loaded tooth contact analysis model that accounts for the precise gear geometry and profile modifications. The numerical simulations show significant tooth separation and occurrence of multi-jump phenomenon in th

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Cao, Yun Dong, and Xing Gang Chen. "Harmonics Analysis Based on FFT of Special Hanning Interpolation Combined with Wavelet Transform." Applied Mechanics and Materials 195-196 (August 2012): 777–82. http://dx.doi.org/10.4028/www.scientific.net/amm.195-196.777.

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In view of the problem that harmonics analysis by fast Fourier Transform can appear a higher error and the serious phenomenon of harmonics leakage and fence, it is put forward that a improved arithmetic that FFT of special Hanning interpolation combined with wavelet transform. It is proved by theory analysis and simulation calculation that: FFT arithmetic of special Hanning interpolation can raise the precision of steady-state harmonics analysis validly. And wavelet transform arithmetic can analyze time-varying harmonics and sudden-changing harmonics precisely. The arithmetic of wavelet transf

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Ishihara, Kazuki, and Jitsuro Sugie. "Uniform asymptotic stability of time-varying damped harmonic oscillators." Proceedings of the American Mathematical Society, Series B 4, no. 4 (2017): 31–46. http://dx.doi.org/10.1090/bproc/30.

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Baghzouz, Y., R. F. Burch, A. Capasso, et al. "Time-Varying Harmonics: Part II-Harmonic Summation and Propagation." IEEE Power Engineering Review 21, no. 10 (2001): 64. http://dx.doi.org/10.1109/mper.2001.4311111.

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Liu, K., and M. R. Kujath. "Response Of Slowly Time-Varying Systems To Harmonic Excitation." Journal of Sound and Vibration 177, no. 3 (1994): 423–32. http://dx.doi.org/10.1006/jsvi.1994.1444.

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Ravindran, Vineetha, Naser Nakhodchi, Sarah Ronnberg, and Math H. J. Bollen. "Assessing Time-Varying Harmonic Interactions in a Wind Park." IEEE Access 9 (2021): 68151–60. http://dx.doi.org/10.1109/access.2021.3076879.

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Nocera, Luigi, and Eric R. Priest. "Bistability of a forced hydromagnetic cavity." Journal of Plasma Physics 46, no. 1 (1991): 153–77. http://dx.doi.org/10.1017/s0022377800016007.

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We study the nonlinear stability of a one-dimensional hydromagnetic cavity into which Alfvén waves are fed by harmonic shear motions of its boundaries and where they interact with slow magnetosonic waves. We use characteristic conditions for the outgoing and ingoing Alfven waves at the boundaries where the magnetosonic oscillations are required to vanish. Forcing of Alfven waves takes place at a frequency close to the eigenfrequency of the lowest-order mode of the cavity. We let the frequency detuning δω vary as a free parameter together with the amplitude of the forcing, the plasma β and the

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Wu, Kaiwei, Chuanbo Ren, Yuanchang Chen, et al. "Vibration Control of Time-Varying Delay under Complex Excitation." Micromachines 12, no. 9 (2021): 1081. http://dx.doi.org/10.3390/mi12091081.

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The existing available research outcomes on vibration attenuation control for time-delay feedback indicate that, for the delay dynamic vibration absorber with fixed time-delay control parameters, under harmonic excitation, a good vibration attenuation control effect occurs on the vibration of the main system. However, the effect is not obvious for complex excitation. Aiming at the above problems, in a short time interval, a harmonic excitation with the same displacement size as the complex excitation was established. Then, by calculating its equivalent amplitude and equivalent frequency, a har

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Wan, Ji Bo, Li Xia Zhang, Zhi Yuan Wei, and Wei Kang. "Comparing and Simulation of APF Control Strategies with Time Varying Inductive Load." Applied Mechanics and Materials 662 (October 2014): 187–90. http://dx.doi.org/10.4028/www.scientific.net/amm.662.187.

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According to the harmonic with phase controlled rectifying technology producing applied oil deposit, this paper adopts APF (active power filter) to filter out the harmonic. The current hysteresis, triangular wave and SVPWM-three kinds of control strategies are discussed. The filter effecting of three strategies are sketched. Aiming at the drawback, it show that the strategy and method with APF based on switched linear theory. The simulation results show that the filtering effect of switched linear theory is better where harmonic is serious; the trigger angle and harmonic is small, and there is

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Li, Jifang, Jidong Wang, Kunlin Song, and Zhen Feng. "An Improved ip − iq Harmonic Detection Method Based on Time-Varying Integral Duration." Mathematical Problems in Engineering 2020 (October 29, 2020): 1–9. http://dx.doi.org/10.1155/2020/5420987.

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By analyzing harmonic related to instantaneous active current and instantaneous reactive current, we propose an improved harmonic detection method to remedy long response delay and low detection accuracy corresponding to harmonic of power system. This method introduces a series connection scheme composed of Low-Pass Filter (LPF) and a current average module firstly. Then, detection accuracy of harmonic current is enhanced by adaptive tuning cut-off frequency of LPF and integration time which was obtained by proposed algorithm of the current average module. Moreover, feedback loop is introduced

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Esch, Thomas, Matthias Rungeler, Florian Heese, and Peter Vary. "Estimation of Rapidly Time-Varying Harmonic Noise for Speech Enhancement." IEEE Signal Processing Letters 19, no. 10 (2012): 659–62. http://dx.doi.org/10.1109/lsp.2012.2211011.

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