Frequency Response Dynamics
Mostrando 1-12 de 64 artigos, teses e dissertações.
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1. Diverging Relaxation Times of Domain Wall Motion Indicating Glassy Dynamics in Ferroelastics
Single crystals of PbZrO3 and LaAlO3 have been studied by Dynamic Mechanical Analysis measurements in the low frequency range f = 0.02-50 Hz. The complex Young's modulus exhibits a quite rich behavior and depends strongly on the direction of the applied dynamic force. The low frequency elastic response in the [110]c-direction is dominated by domain wall moti
Mat. Res.. Publicado em: 24/05/2018
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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. Uncertainty analysis of flexible rotors considering fuzzy parameters and fuzzy-random parameters
Abstract The components of flexible rotors are subjected to uncertainties. The main sources of uncertainties include the variation of mechanical properties. This contribution aims at analyzing the dynamics of flexible rotors under uncertain parameters modeled as fuzzy and fuzzy random variables. The uncertainty analysis encompasses the modeling of uncertain
Lat. Am. j. solids struct.. Publicado em: 2015-10
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4. Thermo-mechanical vibration analysis of annular and circular graphene sheet embedded in an elastic medium
In this study, the vibration behavior of annular and circular graphene sheet coupled with temperature change and under in-plane pre-stressed is studied. Influence of the surrounding elastic medium 011 the fundamental frequencies of the single-layered graphene sheets (SLGSs) is investigated. Both Winkler-type and Pasternak- type models are employed to simulat
Lat. Am. j. solids struct.. Publicado em: 2014-08
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5. 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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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. Stochastic modeling of flexible rotors
Flexible rotors are characterized by inherent uncertainties affecting the parameters that influence the dynamic responses of the system. In this context, the handling of variability in rotor dynamics is a natural and necessary extension of the modeling capability of the existing techniques of deterministic analysis. Among the various methods used to model un
J. Braz. Soc. Mech. Sci. & Eng.. Publicado em: 2012
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8. Identificação inversa de sistemas dinâmicos não-lineares com parâmetros dependentes do deslocamento / Inverse identification for non-linear dynamic systems with displacement dependent parameters
As simulações físicas em laboratórios da indústria automotiva são realizadas utilizando informações colhidas de veículos que são submetidos a ciclos de testes em rotas urbanas. Medir as respostas em pontos específicos durante uma rota de teste, não significa conhecer as excitações a que o veículo esta sendo submetido, visto que este normalment
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 15/07/2011
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9. Controle de atitude de satélites artificiais utilizando um processador digital de sinais / Attitude control of satellites using a digital signal processor
This work deals with the development and implementation of an attitude control system for an artificial satellite using a Digital Signal Processor (DSP). The dissertation presents a complete study of the attitude movement modeling and control for the continuous time systems case, considering the Linear Quadratic Regulator (LQR) and Linear Quadratic Gaussian
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 14/09/2010
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10. A computer simulation study of motoneuron models with active dendrites in response to synaptic inputs. / Estudo por simulação computacional de modelos de motoneurônios com dendrito ativo em resposta a entradas sinápticas.
Mathematical models of motoneurons have been developed as an aid to the understanding of phenomena involving the neuromuscular system, but most of these models have been based on the hypothesis of a passive dendritic tree. This holds for anesthetized animals but not necessarily during normal motor behavior of the intact animal. Experiments with decerebrate a
Publicado em: 2010
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11. CFD and CAA analysis of single stream isothermal jets with noise suppression devices.
Since the 50 s, with the appearance of the turbojet engines, the jet noise is being exhaustively studied, because it is one of the most important source of aircraft noise. Many attempts have been made to reduce the jet noise, including higher by-pass turbofan engines. Chevron nozzles also have been used by the industry to try to reduce the jet noise with a l
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 13/04/2009
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12. Comparison of different identification techniques of vertical structural dynamics of twin-wheeled telescopic landing gear.
The main purpose of this work is to model dynamically the latero-torsional response of the structure of a landing gear using identification techniques. The emphasis is placed on identifying this motion on aircraft twin-wheeled telescopic main landing gears. Between the many possible model structures, a linear polynomial ARX and ARMAX model structures and a s
Publicado em: 2009