Voice instabilities in a three-dimensional continuum model of phonation

2018 ◽  
Vol 143 (3) ◽  
pp. 1965-1965
Author(s):  
Zhaoyan Zhang
Author(s):  
Malena I. Español ◽  
Dmitry Golovaty ◽  
J. Patrick Wilber

In this paper, we derive a continuum variational model for a two-dimensional deformable lattice of atoms interacting with a two-dimensional rigid lattice. The starting point is a discrete atomistic model for the two lattices which are assumed to have slightly different lattice parameters and, possibly, a small relative rotation. This is a prototypical example of a three-dimensional system consisting of a graphene sheet suspended over a substrate. We use a discrete-to-continuum procedure to obtain the continuum model which recovers both qualitatively and quantitatively the behaviour observed in the corresponding discrete model. The continuum model predicts that the deformable lattice develops a network of domain walls characterized by large shearing, stretching and bending deformation that accommodates the misalignment and/or mismatch between the deformable and rigid lattices. Two integer-valued parameters, which can be identified with the components of a Burgers vector, describe the mismatch between the lattices and determine the geometry and the details of the deformation associated with the domain walls.


2011 ◽  
Vol 117-119 ◽  
pp. 438-442
Author(s):  
Hong Xiang Tang ◽  
Zhao Long Hu

A basic 3D Cosserat continuum theory and corresponding finite element formulations are deduced. The deflections of a cantilever beam are analyzed by the 20-nodes solid elements based on the classical continuum theory and Cosserat continuum theory respectively. Compared with analytical solution brought forward by Timoshenko and Goodier, it illustrates that the numerical results based on Coseerat FEM are effective and more accurate and closer to the analytical solutions by choosing an appropriate value of the characteristic internal length, which also testifies the capability of reflecting the intrinsic property of the cantilever beam.


2002 ◽  
Vol 01 (03n04) ◽  
pp. 337-346 ◽  
Author(s):  
SLAVA V. ROTKIN ◽  
VAISHALI SHRIVASTAVA ◽  
KIRILL A. BULASHEVICH ◽  
N. R. ALURU

An atomistic capacitance is derived for a single-wall carbon nanotube in a nano-electromechanical device. Multi-scale calculation is performed using a continuum model for the geometrical capacitance, and statistical and quantum mechanical approaches for the quantum capacitance of the nanotube. The geometrical part of the capacitance is studied in detail using full three-dimensional electrostatics. Results reported in this paper are useful for compact modeling of the electronic and electromechanical nanotube devices.


A simple, general continuum model is proposed for describing the plastic behaviour of a composite material consisting of a metal matrix reinforced by strong fibres. The model is that of an incompressible rigid/plastic continuum which is transversely isotropic—the single preferred direction at any point, and at all times, being the fibre-direction at that point—and which is inextensible in the preferred direction. The principal axes of anisotropy are therefore explicitly determined by the deformation history. The kinematics and general three-dimensional theory for the material are developed and then applied to two cases of plane strain and one of plane stress. The latter is employed in the analysis of previously published experimental data on the yielding of thin fibre-reinforced sheets; good agreement is obtained between the theoretical predictions and the experimental data.


Author(s):  
Ali A. Dawood ◽  
S. Kenny

Finite element modelling procedures to simulate the pipeline mechanical response during reel lay installation are calibrated from the available literature. A three-dimensional continuum model was developed to simulate the bending and straightening processes during reel lay installation and was compared with physical tests conducted within a bending rig and four-point bending test frame. A range of pipeline diameters, wall thicknesses, material grades and weld offsets are examined.


1992 ◽  
Vol 114 (2) ◽  
pp. 227-231 ◽  
Author(s):  
R. Hsu ◽  
T. W. Secomb

A theoretical model is used to analyze oxygen transport in a three-dimensional tissue region containing an arteriole surrounded by an array of capillaries in planes perpendicular to the arteriole. Convective removal of oxygen from the vicinity of the arteriole by nearby capillaries is shown to increase diffusive oxygen loss from the arteriole. This effect depends on the locations of the capillaries, particularly those nearest to the arteriole. The arteriolar oxygen efflux is comparable to that predicted by a previous model which used a continuum approach, but the efflux does not increase with increasing perfusion as rapidly as predicted by the continuum model. Even a small capillary flow rate strongly influences the oxygen field surrounding the arteriole.


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