Acoustic Modeling
Mostrando 1-12 de 28 artigos, teses e dissertações.
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1. Numerical Study of Vibro-Acoustic Responses of Un-Baffled Multi-Layered Composite Structure under Various End Conditions and Experimental Validation
Abstract This article presents the vibro-acoustic modeling and analysis of un-baffled laminated composite flat panels subjected to harmonic point load under various support conditions. The frequency values of the panel are obtained by using simulation model through the commercial finite element package (ANSYS) via batch input technique. Initially, the rate o
Lat. Am. j. solids struct.. Publicado em: 2017-08
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2. Noise Source Distribution of Coaxial Subsonic Jet-Short-Cowl Nozzle
ABSTRACT: The noise source distribution of a short-cowl coaxial jet operating at different velocity ratios is described in this work. This was motivated by an ongoing research about noise prediction of coaxial jets through Acoustic Analogy with purposes of industrial engine application. This research has been carried out between Universidade Federal de Uberl
J. Aerosp. Technol. Manag.. Publicado em: 2014-03
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3. Fuzzy Modeling of Annoyance Caused by Aircraft Noise Using Laeqd and Laeqn Metrics
ABSTRACT: Airport noise presents a major environmental impact arising from aircrafts airport activities, being one of the most complex and difficult mitigation problems. From the environmental point of view, airports cause serious problems to the population. Annoyance caused by noise was evaluated from the Day-Night Level (DNL) metrics proposed by Schultz. H
J. Aerosp. Technol. Manag.. Publicado em: 2013-03
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4. Análise da influência de parâmetros acústicos na inteligibilidade da fala: um estudo em salas de aula de escolas municipais de João Pessoa.
Researchs in the area of environmental comfort conducted in schools reported that, considering the thermophysical variables, the acoustic variable is more important than the other variables, especially in relation to thermal, luminous and indoor air quality variables, since this is the variable that is directly tied to speech intelligibility, with impacts on
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 03/08/2012
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5. Implementation of acoustic materials to the VLS-1 Fairing - a sensitivity analysis using SEA
Satellite launchers are submitted to severe acoustic loads mainly during lift-off where SPL achieve, at the upper parts, values within the range of 140-160 dB. Such an excitation can damage embedded elements, if energy attenuation measures are not adopted. In view of managing the PLF vibro-acoustic environment, numerical techniques are applied to predict ela
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2012-03
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6. Modelagem de ondas ultrassônicas refletidas por superfícies de geometrias diversas. / Modeling for ultrasonics waves of reflected surfaces of various geometries.
Neste trabalho são analisados os campos acústicos gerados por transdutores ultrassônicos planos e circulares, do tipo pistão plano, no modo pulso-eco, trabalhando como emissor e receptor de ondas, com freqüências de 1,6 MHz, 2,25 MHz e 5 MHz. As ondas emitidas por esses transdutores interagem com interfaces denominadas alvos, com diversas geometrias de
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 20/05/2011
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7. Acoustic beam modeling of ultrasonic transducers and arrays using the impulse response and the discrete representation methods
The impulse response of the velocity potential and the discrete representation methods were used in order to model the acoustic field radiated by ultrasonic transducers and arrays. The first method deals with the calculation of the exact impulse response, in which solutions are possible only for simple geometries, such as the circular piston. The second meth
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2011-12
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8. Automatic speech recognition, with large vocabulary, robustness, independence of speaker and multilingual processing
Este trabalho visa prover assistência cognitiva automática via interface de fala, à idosos que moram sozinhos, em situação de risco. Expressões de angústia e comandos vocais fazem parte do vocabulário alvo de reconhecimento de fala. Durante todo o trabalho, o sistema de reconhecimento de fala contínua de grande vocabulário Julius é utilizado em co
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/08/2010
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9. Modelagem Computacional da Propagação Acústica Proveniente de Fontes Multifrequênciais Usando Guias Digitais de Ondas / Computational Modeling of Wave Propagation from Multifrequêncial Source Using Mesh Digital Waveguide
The goal of this research is the creation of virtual acoustic environments, in this context, was constructed a computational tool, aiming to the acoustic modeling of reverberation environment. In this way, it was necessary to elaborate a numerical system able to simulate the wave sound propagation and, mainly its interactions with the surfaces encountered in
Publicado em: 2009
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10. Virtual acoustic prototyping applied to hammer noise of automotive tires / Prototipagem virtual sonora aplicada a ruido de martelamento de pneumaticos automotivos
This study explored the automotive tire noise generation mechanism known as hammer noise, according to the Virtual Acoustic Prototyping approach. A theoretical model available in the literature that considers only the plurality of block pitches in the tread band was implemented. Based on this model, two improved models were developed and implemented consider
Publicado em: 2009
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11. Use of Component Mode Synthesis and Axial Splits in Ducts for Noise Control of Higher Order Duct Mode / Utilização de síntese modal de componentes e particionamento axial de dutos para controle dos modos acústicos de alta ordem
In this study, the proposal of this work is centered in the noise reduction in ducts that became, over the years, a field of intense application. The traditional approach to acoustic noise control in ducts uses passive techniques and fixed reactive silencers to mitigate the noise. In this moment, the Active Control of Noise (ANC) is an attractive approach to
Publicado em: 2009
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12. MODELAGEM SÍSMICA EM ARENITOS: EFEITO DA DISPERSÃO DA VELOCIDADE E DO TIPO DE FLUIDO / SANDSTONE SEISMIC MODELING: EFFECTS OF VELOCITY DISPERSION AND FLUID TYPE
The evaluation of reservoir dynamics during production through time-lapse interpretation has reached a substantial importance in the petroleum industry, mainly in sandstones. This evaluation presents many challenges, mainly concerned to unmask the overlapping of different effects in seismic data due to reservoir changes. Several factors affect seismic proper
Publicado em: 2008