Non Linear Mechanics
Mostrando 25-32 de 32 artigos, teses e dissertações.
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25. Contribuição ao emprego da mecânica do dano para a análise do comportamento dinâmico não-linear de vigas em concreto armado / Contribution to the application of damage mechanics in non-linear dynamic behaviour analysis of reinforced concrete beams
O trabalho trata da formulação e implementação numérica de um modelo de dano para o concreto. O objetivo é o de reproduzir laços de histerese observados experimentalmente em diagramas de tensão-deformação uniaxiais quando, a partir de um certo nível de solicitação, e dano correspondente, passam-se a realizar ciclos de descarregamento e recarrega
Publicado em: 2003
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26. Análise não-linear de pórticos planos, considerando os efeitos do cisalhamento no cálculo de esforços e deslocamentos / Non-linear analysis of reinforced concrete plane frames, considering shear effects to compute internal forces and displacements
Segundo modelos teóricos disponíveis na literatura, foi desenvolvido um algoritmo, com a correspondente implementação de um código computacional, baseado no método dos elementos finitos, a ser aplicado a análises não-lineares físicas e geométricas de pórticos planos em concreto armado, nas quais são levadas em consideração as influências da te
Publicado em: 2002
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27. Critical Phenomena in Gravitational Collapse: The Studies So Far
Studies of black hole formation from gravitational collapse have revealed interesting non-linear phenomena at the threshold of black hole formation. In particular, in 1993 Choptuik studied the collapse of a massless scalar field with spherical symmetry and found some behaviour, which is quite similar to the critical phenomena well-known in Statistical Mechan
Brazilian Journal of Physics. Publicado em: 2001-06
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28. Analise de fraturamento em estruturas de concreto utilizando programas de analise estrutural
This dissertation addresses fracture problems in plain and reinforced concrete, taking the advantages of non-linear analysis of educational and commercial software. Complex problems of concrete structures that develop critical cracks are the topic of this work. Crack propagation and localization are modeled using Finite Element Method (FEM) and Fracture Mech
Publicado em: 2001
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29. Cálculo de esforços e deslocamentos em estruturas de pisos de edifícios, considerando-se a influência das tensões cisalhantes / Determination of displacements and internal forces in reinforced concrete building floor structures, considering the shear stress influence.
In this work, Reinforced concrete grids are analysed, assuming non-linear models based on the damage theory, and also incorporating into shear deformations. The proposed CEB-158 and the NBR-6118 models for reinforced concrete members are discussed, as well as the elastoplastic model assumed for the reinforcement. The Timoshenko s beam theory is studied and a
Publicado em: 2000
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30. Disturbance in respiratory mechanics in infants with bronchiolitis.
The passive flow-volume and partial forced expiratory flow-volume techniques were used to assess pulmonary function in 14 spontaneously breathing infants with acute respiratory syncytial virus bronchiolitis. Two additional infants were studied while paralysed and ventilated. During the acute stage of the illness there was a significant reduction in forced ex
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31. Changes in pennation with joint angle and muscle torque: in vivo measurements in human brachialis muscle.
1. Estimates of pennation in human muscles are usually obtained from cadavers. In this study, pennation of human brachialis was measured in vivo using sonography. Effects of static and dynamic changes in elbow angle and torque were investigated. 2. Pennation was measured in eight subjects using an 80 mm, 5 MHz, linear-array ultrasound transducer to generate
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32. The inhibition of rabbit skeletal muscle contraction by hydrogen ions and phosphate.
1. The effects of phosphate and protons on the mechanics and energetics of muscle contraction have been investigated using glycerinated rabbit psoas muscle. 2. Fibres were fully activated by addition of Ca2+ (pCa 4-5) at 10 degrees C. The velocities of contraction were measured in isotonic load clamps, and the velocities of unloaded fibres were measured by a