Viscoelastic Equations
Mostrando 13-21 de 21 artigos, teses e dissertações.
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13. ANÁLISE DE ESTABILIDADE DE ESCOAMENTOS VISCOSOS E VISCOELÁSTICOS / LINEAR STABILITY ANALYSIS OF VISCOUS AND VISCOELASTIC FLOWS
Steady state,two-dimensional flows may become unstable under two and three-dimensional disturbances, if the flow parameters exceed some critical values. In many practical situations, determining the parameters at which the flow becomes unstable is essential. The complete understanding of viscous and viscoelastic flows requires not only the steady state solut
Publicado em: 2007
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14. COMPORTAMENTO ELONGACIONAL DOS MATERIAIS TERMOPLÁSTICOS COMPÓSITOS / ELONGATIONAL BEHAVIOR OF COMPOSITE THERMOPLASTIC MATERIALS
Composite thermoplastic materials, like glass fiber reforced polypropropylene, are used increasingly in several industries. In particular, glass fiber reinforcement is used to improve the mechanical properties of thermoplastics, due to the high fiber modulous and to the better adesion between the fibers and the polymeric matrix. However, few data of material
Publicado em: 2007
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15. Solução numérica do modelo PTT para escoamentos viscoelásticos com superfícies livres / Numerical solution of the PTT model for viscoelastic surface flows
The aim of this work is to develop a numerical method capable of simulating viscoelastic free surface flows governed by the non-linear constitutive equation PTT (Phan-Thien-Tanner). In this work three numerical methods to simulate vicoelastic Flows of fluids modelled by the PTT equation are presented. Two of these methods were developed to simulate two-dimen
Publicado em: 2006
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16. Time dependent response of a rubber-toughened carbon/epoxy composite with damage accumulation
Polymeric composites are frequently modeled as linear elastic materials. However, matrix-dominated properties, such as transverse and shear modulus, can display significant nonlinear time-dependence, especially under conditions of high stress and aggressive environment. This behavior is primarily due to the viscoelastic nature of the polymeric matrix. In add
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2003-04
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17. Damage theory: microscopic effects of vanishing macroscopic motions
This paper deals with a mechanical model describing the evolution of damage in elastic and viscoelastic materials. The state variables are macroscopic deformations and a microscopic phase parameter, which is related to the quantity of damaged material. The equilibrium equations are recovered by refining the principle of virtual powers including also microsco
Computational & Applied Mathematics. Publicado em: 2003
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18. Soluções transientes de problemas visco-elastodinamicos em meios ilimitados atraves da transformada de Fourier rapida - FFT
This dissertation describes a methodology based on the Fast Fourier Transfonn - FFT to synthesize transient Green and Influence functions for unbounded viscoelastic domains. The FFT algorithm is applied to Green or Influence functions that has been previously obtained in the frequency domain. The techniques used to treat the functions in the frequency domain
Publicado em: 2002
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19. NUMERICAL MODEL FOR A SIMULATION OF VISCOELASTIC FLUIDS VIA FINITE ELEMENTS / UM MODELO NUMÉRICO PARA A SIMULAÇÃO DO ESCOAMENTO DE FLUIDOS VISCOELÁSTICOS VIA ELEMENTOS FINITOS
A new numerical scheme has been introduced for viscoelastic fluid flows. First, it was studied the viscoelastic behavior with particular emphasis on equations in wich the extra stress tensor is not explicity dependent of the velocity field. Two of the most difficult to solve constitutive models have been considered, the Maxwell-B and Oldroyd-B. The numerical
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 02/02/1993
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20. Actin-Myosin Viscoelastic Flow in the Keratocyte Lamellipod
The lamellipod, the locomotory region of migratory cells, is shaped by the balance of protrusion and contraction. The latter is the result of myosin-generated centripetal flow of the viscoelastic actin network. Recently, quantitative flow data was obtained, yet there is no detailed theory explaining the flow in a realistic geometry. We introduce models of vi
The Biophysical Society.
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21. Fractal ladder models and power law wave equations
The ultrasonic attenuation coefficient in mammalian tissue is approximated by a frequency-dependent power law for frequencies less than 100 MHz. To describe this power law behavior in soft tissue, a hierarchical fractal network model is proposed. The viscoelastic and self-similar properties of tissue are captured by a constitutive equation based on a lumped
Acoustical Society of America.