Dynamic Instability Frequency
Mostrando 1-12 de 25 artigos, teses e dissertações.
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1. GFEM STABILIZATION TECHNIQUES APPLIED TO DYNAMIC ANALYSIS OF NON-UNIFORM SECTION BARS
Abstract The Finite Element Method (FEM), although widely used as an approximate solution method, has some limitations when applied in dynamic analysis. As the loads excite the high frequency and modes, the method may lose precision and accuracy. To improve the representation of these high-frequency modes, we can use the Generalized Finite Element Method (GF
Lat. Am. j. solids struct.. Publicado em: 29/10/2018
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2. Analysis of the Dynamic Behavior of a Rotating Composite Hollow Shaft
Abstract In the present paper, a simplified homogenized beam theory is used in the context of a numerical investigation regarding the dynamic behavior of a rotating composite hollow shaft. For this aim, a horizontal flexible composite shaft and a rigid disc form the considered simple supported rotating system. The mathematical model of the rotor is derived f
Lat. Am. j. solids struct.. Publicado em: 2017-01
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3. Application of Iteration Perturbation Method in studying dynamic pull-in instability of micro-beams
In the present study, dynamic pull-in instability of electrostatically-actuated micro-beams is investigated through proposing the nonlinear frequency amplitude relationship. An approximate analytical expression of the fundamental natural frequency is presented by modern asymptotic approach namely Iteration Perturbation Method (IPM). Influences of vibrational
Lat. Am. j. solids struct.. Publicado em: 2014-12
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4. Parametric resonance in concrete beam-columns
A dynamic instability, called parametric resonance, is exhibited by undampedelastic beam-columns when under the action of pulsating axial force. The scope of the existing theory of parametric resonance is restricted to physically linear beam-columns undergoing finite lateral displacements. In this Paper, the dynamic behaviour of physically nonlinear elastic
Lat. Am. j. solids struct.. Publicado em: 2014-11
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5. Dynamic pull-in instability of geometrically nonlinear actuated micro-beams based on the modified couple stress theory
This paper investigates the dynamic pull-in instability of vibrating micro-beams undergoing large deflection under electrosatically actuation. The governing equation of motion is derived based on the modified couple stress theory. Homotopy Perturbation Method is employed to produce the high accuracy approximate solution as well as the second-order frequency-
Lat. Am. j. solids struct.. Publicado em: 2014-10
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6. Análise e otimização da resposta em dinâmica de rotores
Great efforts are been made recently in order to diagnose vibrations in structures and equipments. Rotary machines require even greater attention, for they carry the risk of auto-excitation. This paper has as an objective the exposition a rotor dynamics methodology to minimize the response amplitude in the frequency domain. With this goal, the rotor is discr
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2012
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7. Liquid rocket combustion chamber acoustic characterization
Abstract: Over the last 40 years, many solid and liquid rocket motors have experienced combustion instabilities. Among other causes, there is the interaction of acoustic modes with the combustion and/or fluid dynamic processes inside the combustion chamber. Studies have been showing that, even if less than 1% of the available energy is diverted to an acousti
J. Aerosp. Technol. Manag.. Publicado em: 2010-12
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8. NONLINEAR DYNAMICS, INSTABILITY AND CONTROL OF STRUCTURAL SYSTEMS WITH MODAL INTERACTION / DINÂMICA NÃO-LINEAR, INSTABILIDADE E CONTROLE DE SISTEMAS ESTRUTURAIS COM INTERAÇÃO MODAL
The aim of this thesis is to study the influence of coupled buckling modes on the static and particularly on the nonlinear dynamic behavior of structural components liable to buckling. For this, two discrete two degrees of freedom models known for their complex nonlinear behavior are selected: the well-known Augusti¿s model and a simplified model of cable-s
Publicado em: 2010
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9. Transient stability of empty and fluid-filled cylindrical shells
In the present work a qualitatively accurate low dimensional model is used to study the non-linear dynamic behavior of shallow cylindrical shells under axial loading. The dynamic version of the Donnell non-linear shallow shell equations are discretized by the Galerkin method. The shell is considered to be initially at rest, in a position corresponding to a p
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2006-09
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10. Identificação modal de uma estrutura aeronáutica via algoritmo de realização de sistemas / Modal identification of an aeronautical structure via the eigensystem realization algorithm
The determination of the dynamic characteristics of aircraft structures has become an extremely important issue in the aerospace industry, primarily due to the continuous demand for lighter and consequently more flexible structures. In this context, most aerospace structural system must be subjected to some form of modal verification prior to flight in order
Publicado em: 2002
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11. Kinetics of microtubule catastrophe assessed by probabilistic analysis.
Microtubules are cytoskeletal filaments whose self-assembly occurs by abrupt switching between states of roughly constant growth and shrinkage, a process known as dynamic instability. Understanding the mechanism of dynamic instability offers potential for controlling microtubule-dependent cellular processes such as nerve growth and mitosis. The growth to shr
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12. How the transition frequencies of microtubule dynamic instability (nucleation, catastrophe, and rescue) regulate microtubule dynamics in interphase and mitosis: analysis using a Monte Carlo computer simulation.
Microtubules (MTs) in newt mitotic spindles grow faster than MTs in the interphase cytoplasmic microtubule complex (CMTC), yet spindle MTs do not have the long lengths or lifetimes of the CMTC microtubules. Because MTs undergo dynamic instability, it is likely that changes in the durations of growth or shortening are responsible for this anomaly. We have use