Nonlinear Oscillations
Mostrando 1-12 de 70 artigos, teses e dissertações.
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1. Simple but accurate periodic solutions for the nonlinear pendulum equation
Abstract Despite its elementary structure, the simple pendulum oscillations are described by a nonlinear differential equation whose exact solution for the angular displacement from vertical as a function of time cannot be expressed in terms of an elementary function, so either a numerical treatment or some analytical approximation is ultimately demanded. Su
Rev. Bras. Ensino Fís.. Publicado em: 21/09/2018
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2. Fourier analysis of nonlinear pendulum oscillations
Since the times of Galileo, it is well-known that a simple pendulum oscillates harmonically for any sufficiently small angular amplitude. Beyond this regime and in absence of dissipative forces, the pendulum period increases with amplitude and then it becomes a nonlinear system. Here in this work, we make use of Fourier series to investigate the transition f
Rev. Bras. Ensino Fís.. Publicado em: 20/07/2017
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3. A New Algorithm for Shock Sensor Calculation at Supersonic Speeds on a 3D-Unstructured Grid
ABSTRACT In this paper, 3-Dsupersonic flow around two types of wings is solved using a new algorithm for shock sensor calculation. A dual-time-stepping implicit method with 2nd-order accuracy is used for time integration of the equations. In each real time step, the non-linear system of equations is solved by iterating in pseudo-time, using a multi-step inte
J. Aerosp. Technol. Manag.. Publicado em: 2016-12
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4. Ultrafast Dynamics of Au Nanopyramid Interfaces Prepared by Nanosphere Lithography: Effect of Substrate Chemical Composition
This work describes ultrafast spectroscopy studies of Au triangular pyramid particle arrays deposited over glass (termed Au/glass), and 190 nm indium tin oxide (ITO) film (termed Au/ITO/glass) prepared by nanosphere lithography. The linear absorption spectra of Au/glass and Au/ITO/glass exhibit surface plasmon resonances at 800 and 870 nm, respectively, in g
J. Braz. Chem. Soc.. Publicado em: 2016-02
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5. Long-term correlation of the electrocorticogram as a bioindicator of brain exposure to ionizing radiation
Understanding the effects of radiation and its possible influence on the nervous system are of great clinical interest. However, there have been few electrophysiological studies on brain activity after exposure to ionizing radiation (IR). A new methodological approach regarding the assessment of the possible effects of IR on brain activity is the use of line
Braz J Med Biol Res. Publicado em: 12/06/2015
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6. Explicit solution of the large amplitude transverse vibrations of a flexible string under constant tension
This paper presents the analytical simulation of string with large amplitudes using the Variational Iteration Method (VIM) and Hamiltonian Approach (HA). In order to verify the precision of the presented methods, current results were compared with He's Variational Approach and Runge-Kutta 4th order. It has been found that these methods are well suited for a
Lat. Am. j. solids struct.. Publicado em: 2014-05
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7. Dynamic model of large amplitude vibration of a uniform cantilever beam carrying an intermediate lumped mass and rotary inertia
In this paper, a mathematical model of large amplitude vibration of a uniform cantilever beam arising in the structural engineering is proposed. Two efficient and easy mathematical techniques called variational iteration method and He's variational approach are used to solve the governing differential equation of motion. To assess the accuracy of solutions,
Lat. Am. j. solids struct.. Publicado em: 2014-03
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8. Study of nonlinear vibration of Euler-Bernoulli beams by using analytical approximate techniques
In this paper, nonlinear responses of a clamped-clamped buckled beam are investigated. Two efficient and easy mathematical techniques called He's Variational Approach and Laplace Iteration Method are used to solve the governing differential equation of motion. To assess the accuracy of solutions, we compare the results with the Runge-Kutta 4th order. The res
Lat. Am. j. solids struct.. Publicado em: 2014-01
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9. Investigation of the heave dynamics of Air Cushion Vehicles (ACV): parametric and chaotic studies
A highly non-linear model for the dynamics behavior of Air Cushion Vehicles (ACV) is presented. In this model the compressible Bernoulli's equation, the Newton's second law of motion, and the nonlinear isentropic relations are used to predict the dynamics behavior of only the vertical response of the ACV in both time and frequency domains. In this paper the
Lat. Am. j. solids struct.. Publicado em: 2013-07
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10. Fenômenos não-lineares na eletro-oxidação do íon boroidreto / Non-linear phenomena during borohydride electro-oxidation
Apesar de toda a atenção dada à eletro-oxidação do íon boroidreto, pela possibilidade de seu uso em células a combustível, pouco se tem discutido a respeito das instabilidades cinéticas associadas a esse processo. A maioria das pesquisas tem como foco o estudo da cinética dos processos na região de baixos sobrepotenciais, numa região relativament
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 14/05/2012
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11. Análise de movimentos periódicos em sistemas bi-linear com folga simétrica
O presente trabalho apresenta a modelagem matemática de um sistema vibracional com excitação harmônica da base. Esse tipo de sistema tem sido estudado por vários pesquisadores que exploraram muitos aspectos da dinâmica global. No entanto, na grande parte dos sistemas estudados, o sistema era modelado para uma característica de vibroimpacto. No sistema
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/03/2012
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12. Análise do comportamento eletroaeroelástico de uma seção típica para geração piezelétrica de energia / Electroaeroelastic behavior analysis of a typical section for piezoelectric energy harvesting
Converting aeroelastic vibrations into electricity for low power generation has received growing attention over the past few years. In addition to potential applications for aerospace structures, the goal is to develop alternative and scalable configurations for wind energy harvesting to use in wireless electronic systems. The use of a typical airfoil sectio
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 13/02/2012