The effect of wall depletion and hydrodynamic interactions on stress-gradient-induced polymer migration

Soft Matter ◽  
2016 ◽  
Vol 12 (27) ◽  
pp. 5883-5897 ◽  
Author(s):  
Hossein Rezvantalab ◽  
Guorui Zhu ◽  
Ronald G. Larson
Keyword(s):  
Stress Gradient ◽  
Continuum Theory ◽  
Hydrodynamic Interactions ◽  
Wall Depletion ◽  
Polymer Migration ◽  
Mesoscopic Simulations

Predicting the stress-gradient-induced migration of polymers in presence of solid boundaries: continuum theory and mesoscopic simulations.

scholarly journals Correction: The effect of wall depletion and hydrodynamic interactions on stress-gradient-induced polymer migration

Soft Matter ◽  
2017 ◽  
Vol 13 (36) ◽  
pp. 6270-6270
Author(s):  
Hossein Rezvantalab ◽  
Guorui Zhu ◽  
Ronald G. Larson
Keyword(s):  
Soft Matter ◽  
Stress Gradient ◽  
Hydrodynamic Interactions ◽  
Wall Depletion ◽  
Polymer Migration

Correction for ‘The effect of wall depletion and hydrodynamic interactions on stress-gradient-induced polymer migration’ by Hossein Rezvantalab et al., Soft Matter, 2016, 12, 5883–5897.

A continuum theory of stress gradient plasticity based on the dislocation pile-up model

2014 ◽  
Vol 80 ◽  
pp. 350-364 ◽  
Author(s):  
Dabiao Liu ◽  
Yuming He ◽  
Bo Zhang ◽  
Lei Shen
Keyword(s):  
Stress Gradient ◽  
Continuum Theory ◽  
Gradient Plasticity ◽  
Pile Up

Stress gradient continuum theory

2012 ◽  
Vol 40 ◽  
pp. 16-25 ◽  
Author(s):  
Samuel Forest ◽  
Karam Sab
Keyword(s):  
Stress Gradient ◽  
Continuum Theory

A Continuum Theory That Couples Creep and Self-Diffusion

2004 ◽  
Vol 71 (5) ◽  
pp. 646-651 ◽  
Author(s):  
Z. Suo
Keyword(s):  
Film Thickness ◽  
Chemical Potential ◽  
Relative Rate ◽  
Diffusion Flux ◽  
Stress Gradient ◽  
Continuum Theory ◽  
Potential Gradient ◽  
Self Diffusion ◽  
Component Material ◽  
Coupled Theory

In a single-component material, a chemical potential gradient or a wind force drives self-diffusion. If the self-diffusion flux has a divergence, the material deforms. We formulate a continuum theory to be consistent with this kinematic constraint. When the diffusion flux is divergence-free, the theory decouples into Stokes’s theory for creep and Herring’s theory for self-diffusion. A length emerges from the coupled theory to characterize the relative rate of self-diffusion and creep. For a flow in a film driven by a stress gradient, creep dominates in thick films, and self-diffusion dominates in thin films. Depending on the film thickness, either stress-driven creep or stress-driven diffusion prevails to counterbalance electromigration. The transition occurs when the film thickness is comparable to the characteristic length of the material.

Stress-gradient-induced polymer migration: Perturbation theory and comparisons to stochastic simulations

2016 ◽  
Vol 60 (2) ◽  
pp. 327-343 ◽  
Author(s):  
Guorui Zhu ◽  
Hossein Rezvantalab ◽  
Elnaz Hajizadeh ◽  
Xiaoyi Wang ◽  
Ronald G. Larson
Keyword(s):  
Perturbation Theory ◽  
Stress Gradient ◽  
Stochastic Simulations ◽  
Polymer Migration

Fracture Analysis in the Continuum Theory of Stress Gradient Plasticity

2016 ◽  
Vol 08 (08) ◽  
pp. 1650091 ◽  
Author(s):  
Siamak Soleymani Shishvan ◽  
Mirsalim Ghoddousifar
Keyword(s):  
Stress Level ◽  
Stress Gradient ◽  
Crack Tip ◽  
Continuum Theory ◽  
Higher Order ◽  
Complex Stress State ◽  
Plastic Behavior ◽  
Stationary Mode ◽  
Gradient Plasticity ◽  
The Continuum

Plastic deformation around a stationary mode I crack in an isotropic material is studied within the continuum theory of stress gradient plasticity ([Formula: see text]GP). This model, as a lower-order plasticity theory, has been quite successful in predicting the size-dependent plastic behavior in micro-torsion as well as micro-bending. However, its application to a problem involving a complex stress state reveals here that it has to be modified with a proper measure of stress gradient in the continuum context. To this end, a new measure of stress gradient is proposed and assessed appropriately. It is then employed to investigate crack tip stress fields within the [Formula: see text]GP theory. Analyses show that a higher stress level is predicted near the crack tip using the [Formula: see text]GP theory when compared with the classical plasticity predictions. The increase of stress level due to stress gradient effects is predicted around 35% which is enough for cleavage cracking. However, relatively higher stress levels were expected due to large stress gradients near the crack tip. Therefore, either a higher-order formulation or involving higher-order spatial gradients of stress is required to study fracture with the [Formula: see text] GP theory.

scholarly journals Continuum thermomechanics of nonlinear micromorphic, strain and stress gradient media

2020 ◽  
Vol 378 (2170) ◽  
pp. 20190169 ◽  
Author(s):  
Samuel Forest
Keyword(s):  
Strain Gradient ◽  
Stress Gradient ◽  
Continuum Theory ◽  
Research Field ◽  
Irreversible Processes ◽  
Current Debate ◽  
Generalized Continua ◽  
Generalized Standard Materials ◽  
New Research ◽  
Continuum Theories

A comprehensive constitutive theory for the thermo-mechanical behaviour of generalized continua is established within the framework of continuum thermodynamics of irreversible processes. It represents an extension of the class of generalized standard materials to higher order and higher grade continuum theories. It reconciles most existing frameworks and proposes some new extensions for micromorphic and strain gradient media. The special case of strain gradient plasticity is also included as a contribution to the current debate on the consideration of energetic and dissipative mechanisms. Finally, the stress gradient continuum theory emerges as a new research field for which an elastic-viscoplastic theory at finite deformations is provided for the first time. This article is part of the theme issue ‘Fundamental aspects of nonequilibrium thermodynamics’.

Stress-gradient-induced polymer migration in Taylor–Couette flow

Soft Matter ◽  
2017 ◽  
Vol 13 (35) ◽  
pp. 5942-5949 ◽  
Author(s):  
Elnaz Hajizadeh ◽  
Ronald G. Larson
Keyword(s):  
Couette Flow ◽  
Brownian Dynamics ◽  
Stress Gradient ◽  
Recent Theory ◽  
Taylor Couette ◽  
Dynamics Simulations ◽  
Polymer Migration ◽  
Brownian Dynamics Simulations ◽  
First Time ◽  
Taylor Couette Flow

This work applies our recent theory for stress-gradient-induced migration to Taylor–Couette flow, and has for the first time confirmed the theory using Brownian dynamics simulations.

Freeze fracture imaging and computer simulation of liposome structure: Membrane geometry and defects

1983 ◽  
Vol 41 ◽  
pp. 646-647
Author(s):  
Joseph A. Zasadzinski
Keyword(s):  
Liquid Crystalline ◽  
Freeze Fracture ◽  
Continuum Theory ◽  
Closed Surfaces ◽  
Straight Line ◽  
Low Weight ◽  
Concentric Spheres ◽  
Membrane Geometry ◽  
Dupin Cyclides ◽  
Limiting Case

At low weight fractions, many surfactant and biological amphiphiles form dispersions of lamellar liquid crystalline liposomes in water. Amphiphile molecules tend to align themselves in parallel bilayers which are free to bend. Bilayers must form closed surfaces to separate hydrophobic and hydrophilic domains completely. Continuum theory of liquid crystals requires that the constant spacing of bilayer surfaces be maintained except at singularities of no more than line extent. Maxwell demonstrated that only two types of closed surfaces can satisfy this constraint: concentric spheres and Dupin cyclides. Dupin cyclides (Figure 1) are parallel closed surfaces which have a conjugate ellipse (r1) and hyperbola (r2) as singularities in the bilayer spacing. Any straight line drawn from a point on the ellipse to a point on the hyperbola is normal to every surface it intersects (broken lines in Figure 1). A simple example, and limiting case, is a family of concentric tori (Figure 1b).To distinguish between the allowable arrangements, freeze fracture TEM micrographs of representative biological (L-α phosphotidylcholine: L-α PC) and surfactant (sodium heptylnonyl benzenesulfonate: SHBS)liposomes are compared to mathematically derived sections of Dupin cyclides and concentric spheres.

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