scholarly journals Orientation and Aggregation of Polymer Chains in the Straight Electrospinning Jet

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4295
Author(s):  
Andrey Subbotin ◽  
Valery Kulichikhin
Keyword(s):  
Polymer Chains ◽  
Elastic Model ◽  
Rectilinear Motion ◽  
Straight Section ◽  
Rheological Equation ◽  
Flow Rates ◽  
Jet Behavior ◽  
Limited Length ◽  
Solution Aggregation ◽  
Nonlinear Elastic

The dynamics of a straight section of a jet arising during the electrospinning of a polymer solution without entanglements, and the orientation of polymer chains in the jet were explored based on the analysis of the forces balance equation and the rheological equation of the finitely extensible nonlinear elastic model. Two modes of the jet behavior were predicted. At relatively low volumetric flow rates, the straight jet has a limited length, after that, its rectilinear motion becomes impossible, while at higher flow rates, the jet always remains straightforward. It is shown that polymer chains in a jet can be strongly stretched, which leads to phase separation in a spinning solution. Aggregation of the stretched chains was also studied and the parameters of the emerging inhomogeneous structure were predicted.

scholarly journals Features of the Behavior of a Polymer Solution Jet in Electrospinning

2021 ◽  
Vol 63 (2) ◽  
pp. 172-179
Author(s):  
A. V. Subbotin
Keyword(s):  
Numerical Analysis ◽  
Polymer Solution ◽  
Electric Fields ◽  
Flow Direction ◽  
Polymer Chains ◽  
Force Balance ◽  
Straight Section ◽  
Rheological Equation ◽  
Strong Fields ◽  
Force Balance Equation

Abstract Using the numerical analysis of the force balance equation and the rheological equation of the model of finitely extensible chains, the dynamics of a charged jet during the electrospinning of a polymer solution and the orientation of macromolecules in the jet are studied. In fairly weak electric fields, the jet always remains rectilinear, while in strong fields the straight section of the jet has a finite length, after which the motion of the jet becomes unstable. This behavior is due to the competition between inertial and viscoelastic forces, with viscoelasticity dominating in strong fields. It is found that polymer chains in the jet are strongly stretched along the flow direction.

scholarly journals Analysis and approximation of a strain-limiting nonlinear elastic model

2014 ◽  
Vol 20 (1) ◽  
pp. 92-118 ◽  
Author(s):  
M Bulíček ◽  
J Málek ◽  
E Süli
Keyword(s):  
Elastic Model ◽  
Nonlinear Elastic

scholarly journals Comparison between Duncan and Chang’s EB Model and the Generalized Plasticity Model in the Analysis of a High Earth-Rockfill Dam

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Weixin Dong ◽  
Liming Hu ◽  
Yu Zhen Yu ◽  
He Lv
Keyword(s):  
Constitutive Models ◽  
Elastic Model ◽  
Plasticity Model ◽  
Rockfill Dam ◽  
Generalized Plasticity ◽  
Rockfill Materials ◽  
Confining Pressures ◽  
Mechanical Behaviours ◽  
Nonlinear Elastic ◽  
Relationship Of

Nonlinear elastic model and elastoplastic model are two main kinds of constitutive models of soil, which are widely used in the numerical analyses of soil structure. In this study, Duncan and Chang's EB model and the generalized plasticity model proposed by Pastor, Zienkiewicz, and Chan was discussed and applied to describe the stress-strain relationship of rockfill materials. The two models were validated using the results of triaxial shear tests under different confining pressures. The comparisons between the fittings of models and test data showed that the modified generalized plasticity model is capable of simulating the mechanical behaviours of rockfill materials. The modified generalized plasticity model was implemented into a finite element code to carry out static analyses of a high earth-rockfill dam in China. Nonlinear elastic analyses were also performed with Duncan and Chang's EB model in the same program framework. The comparisons of FEM results andin situmonitoring data showed that the modified PZ-III model can give a better description of deformation of the earth-rockfill dam than Duncan and Chang’s EB model.

Rheological Flows in Channels With Complex Geometry and Porous Medium

Volume 1 ◽  
2004 ◽  
Author(s):  
Ramiz S. Gurbanov ◽  
Eldar T. Abdinov ◽  
Sayavur I. Bakhtiyarov
Keyword(s):  
Porous Medium ◽  
Complex Variable ◽  
Rheological Behavior ◽  
Complex Geometry ◽  
Variable Method ◽  
Rheological Equation ◽  
Flow Rates ◽  
Approach Method ◽  
Flow Through ◽  
First Time

The article describes a new method of rheological stationary fluids flow calculation in pipes and channels. By means of a complex variable method the universal formulae for velocities and flow rates distribution have been received. A technique called “linearization of single-bonded area” has been used in this research. The quasi Newtonian approach method has been suggested for the first time. To study of rheological stationary fluids flow in porous medium the model of “hypothetical canal” is assumed. This model allows predicting the rheological behavior of anomalous fluids flow through porous medium based on the results obtained on the capillary flowmeter. The “real” rheological equation of condition construction has been pointed out. The resistance laws generalized for the rheological stationary fluid have been received.

scholarly journals Analysis of Stress Deformation Characteristics of Composite Geomembrane Rock-Fill Dam with Core Wall

2013 ◽  
Vol 470 ◽  
pp. 962-965
Author(s):  
Dong Yan Ding ◽  
Jian Min Ren
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Elastic Model ◽  
Deformation Characteristics ◽  
Distribution Rule ◽  
Dimensional Finite Element ◽  
Stress And Deformation ◽  
Three Dimensional Finite Element ◽  
Nonlinear Elastic

The Chengzigou hydropower station of composite geomembrane rockfill dam as an example of the dam body and the composite geotechnical membrane stress and deformation characteristics are used nonlinear elastic model - Duncan EB model establish three-dimensional finite element model of rockfill,by using the large finite element softwareFLAC3D,whice provided geogrid element to simulate lexible geomembrane shear interaction with soil.The stress and deformation of the dam and the composite geomembrane is calculated under two conditionscompletion period and impoundment period.And analyze the change of the stress and strain distribution rule,whice will provide the basis for the design of the geomembrane.

Application of Fractional Derivatives to Modeling the Quasi-Static Response of Polyurethane Foam

2003 ◽  
Author(s):  
Rong Deng ◽  
Patricia Davies ◽  
Anil K. Bajaj
Keyword(s):  
System Identification ◽  
Polyurethane Foam ◽  
Elastic Model ◽  
Compression Tests ◽  
Static Compression ◽  
Identification Method ◽  
Dissipative Effects ◽  
Identification Technique ◽  
Nonlinear Elastic ◽  
Quasi Static Compression

A fractional derivative model of dissipative effects is combined with a nonlinear elastic model to model the response of polyurethane foam in quasi-static compression tests. A system identification method is developed based on a separation of the elastic and viscoelastic parts of the response, which is possible because of symmetries in the imposed deformation timehistory. Simulations are used to evaluate the proposed identification method when noise is present in the response. The system identification technique is also applied with some success to experimental data taken from several compression experiments on two types of polyurethane foam blocks.

Duncan-Chang Nonlinear Elastic Model Considered Loess Structure

2011 ◽  
Vol 90-93 ◽  
pp. 176-181
Author(s):  
Chang Lu Chen ◽  
Sheng Jun Shao ◽  
Lin Ma
Keyword(s):  
Nonlinear Model ◽  
Stress Ratio ◽  
Structural Parameters ◽  
Strain Curve ◽  
Triaxial Tests ◽  
Model Parameters ◽  
Elastic Model ◽  
Stress Strain ◽  
Nonlinear Elastic ◽  
Intact Loess

Duncan-Chang nonlinear model has been modified and applied to the structural loess calculation. Based on structural studies and conventional triaxial tests, this paper has analyzed the mechanical properties of intact loess and the relationship between the stress ratio structural parameters and the strain, then the expression of generalized shear strain and stress ratio structural parameters are given to facilitate the engineering applications. On this basis, the stress-strain curve of intact loess was corrected by the use of the stress ratio structural parameters. The form of the intact loess stress-strain curves which have been revised has changed hardening from the softening or weak softening. The results show that the modified stress-strain curves of intact loess can apply Duncan- Chang nonlinear model to calculate and the model parameters are reasonable and effective. This method provides Duncan-Chang nonlinear model which is widely used in engineering with a new ways and means in intact structural loess application.

Three-Dimensional Nonlinear Finite Element Analysis on the Concrete Face Cock-Fill Dam of TianChi Upper Reservoir

2013 ◽  
Vol 838-841 ◽  
pp. 1763-1767
Author(s):  
Shuang Mei Chang ◽  
Wen She He ◽  
Yu Qiang Cheng ◽  
Su Min Zhao
Keyword(s):  
Finite Element ◽  
Water Pressure ◽  
Three Dimensional ◽  
Elastic Model ◽  
Finite Element Software ◽  
Dimensional Finite Element ◽  
Stress And Deformation ◽  
Three Dimensional Finite Element ◽  
Nonlinear Elastic ◽  
Concrete Face

Taking the concrete face cock-fill dam upper reservoir of Tianchi as an example, the stress and deformation characteristics of concrete face rock-fill dam are studied in-depth in this paper. The article builds a fine three-dimensional finite element model of Tianchi upper reservoir by a nonlinear elastic model of the finite element software ADINA. The stress and deformation of the two conditions under completion and storage for the dam are calculated ,which will be analyzed to obtain stress - strain distribution of the dam in two conditions, comparing dam stress and deformation before and after impoundment to get impact of the water pressure on the dam stress and deformation: comparing after impoundment and completion , the dam water level displacement of upstream side from role of horizontal water pressure will increase , the dam upstream offsets to downstream , but the offset is little ; Due to dam is affected by vertical hydrostatic pressure and uplift pressure after impoundment , the dam settlement is slightly less than the completion in storage. KEY WORDS: Tianchi upper reservoir, The concrete face cock-fill dam, Three-dimensional finite element, Nonlinear elastic model, Analysis of stress and deformation

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