Elastic Wave Propagation
Mostrando 13-22 de 22 artigos, teses e dissertações.
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13. Transient wave propagation phenomena at visco-elastic half-spaces under distributed surface loadings
This article analyzes the transient wave propagation phenomena that take place at 2D viscoelastic half-spaces subjected to spatially distributed surface loadings and to distinct temporal excitations. It starts with a fairly detailed review of the existing strategies to describe transient analysis for elastic and viscoelastic continua by means of the Boundary
Lat. Am. j. solids struct.. Publicado em: 2012-08
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14. Visualização de fenômenos de propagação de ondas mecânicas em meio contínuo / Visualization of mechanical wave propagation phenomena in continuous medium
Nas últimas décadas, o estudo dos fenômenos de propagação de ondas mecânicas e de suas consequências tem recebido crescente atenção de grupos de pesquisa de variados ramos da engenharia, sobretudo daqueles dedicados ao desenvolvimento de métodos computacionais para resolução de problemas complexos na área da Mecânica dos Meios Contínuos (MMC).
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 04/08/2011
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15. Filtros acústicos em cristais fonônicos
In this work, we have studied the acoustic phonon wave propagation within the periodic and quasiperiodic superlattices of Fibonacci type. These structures are formed by phononic crystals, whose periodicity allows the raise of regions known as stop bands, which prevent the phonon propagation throughout the structure for specific frequency values. This p
Publicado em: 2009
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16. Ultrasonic characterization of composite materials. / Caracterização de materiais compostos por ultra-som.
In this work, two ultrasonic non destructive techniques were implemented in a water tank and used to determine the elastic constants of glass-epoxy composites samples. The first is the through-transmission technique implemented with a pair of ultrasonic transducers. The second is the back-reflection technique that uses a single transducer in pulse-eco mode.
Publicado em: 2006
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17. AplicaÃÃo dos mÃtodos de pulso-eco e resonÃncia acÃstica para caracterizaÃÃo nÃo destrutiva de propriedades elÃsticas e microestruturais de vidros especiais e aÃo ferrÃtico degradado por fluÃncia
The elastic properties, homogeneity, attenuation of the propagation of ultrasonic waves and associated structure with some types of special glass were analyzed with the pulse-echo method. A total of seven samples of glass containing neodymium, lead, zirconium and niobium, as additives were analyzed. As a result, elastic constants such as coefficient of Poiss
Publicado em: 2005
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18. STUDY OF SCATTERING OF ULTRASOUND WAVES BY DEFECTIVE INTERFACES / ESTUDO DO ESPALHAMENTO DE ONDAS ULTRA-SONICAS POR INTERFACES DEFEITUOSAS EM JUNTAS COLADAS
It is well known that the global strength of multi-layered composite structures strongly depends on the quality of the adhesion between its constituent elements. Imperfections along interfaces of adhesion can strongly compromise structure s performance. The characterization of such defects is a very difficult task. The main goal of this study is the developm
Publicado em: 2002
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19. Análise do problema harmônico de radiação e difusão acústica, usando o método dos elementos de contorno. / Harmonic analysis of the acoustic radiation and scattering problems, using boundary element methods.
In this work, acoustic and elastic wave propagation problems in 2D, in frequency domain, are studied and formulated with the Boundary Element Methods. The formulation is based on the integral representations derived from the differential equations that govern the phenomena of acoustic wave propagation in a fluid medium and elastic wave propagation inside an
Publicado em: 2000
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20. Modelagem e inversão de coeficientes de reflexão em meios fraturados usando algoritmo genetico
We present a method for the exact modeling and inversion of multi-azimutal qP-wave reflection coefficients at an interface separating two anisotropic media with at least one of its planes of symmetry paralIel to the interface, Le., monoclinic or higher symmetries. To illustrate the procedure, we compute qP-wave reflection coefficients at an interface separat
Publicado em: 1998
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21. Elementos infinitos para tratamento de problemas da viscoelastodinamica estacionaria pelo metodo dos elementos finitos
The present thesis reports an overview and a numerical implementation of the Finite Element Method (FEM) in wich the so called "infinite elements" are included to model the Sommerfeld s radiation condition or the geometric damping in the stationary response of unbounded (visco-) elastic domains. Initially one dimensional infinite elements are formulated and
Publicado em: 1996
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22. Pulse-wave propagation in an artery with leakage into small side branches.
Linear pulse propagation theory is applied to a network of elastic tubes. The network is specialized to one having a main branch with many low-admittance side branches. Continuum approximations and an asymptotic analysis of side-branch network input admittance reduce the original network to a tapered leaky tube. The outflow law is equivalent to distributed W