An experimental study on the criteria for failure of polymer melts in uniaxial extension: The test case of a polyisobutylene melt in different deformation regimes

2010 ◽  
Vol 54 (3) ◽  
pp. 605-618 ◽  
Author(s):  
V. C. Barroso ◽  
R. J. Andrade ◽  
J. M. Maia
Keyword(s):  
Experimental Study ◽  
Polymer Melts ◽  
Uniaxial Extension ◽  
Test Case

Experimental Study of a CFD Validation Test Case for Turbulent Separated Flows

2020 ◽  
Author(s):  
Owen Williams ◽  
Madeline Samuell ◽  
E. Sage Sarwas ◽  
Matthew Robbins ◽  
Antonino Ferrante
Keyword(s):  
Experimental Study ◽  
Separated Flows ◽  
Test Case ◽  
Cfd Validation ◽  
Validation Test

Characterisation of an Industrial Polymer Melt Through Either Uniaxial Extension or Exponential Shear Data: An Application of the Pom-Pom Model

2003 ◽  
Vol 13 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Suneel ◽  
Richard S. Graham ◽  
Tom C.B. McLeish
Keyword(s):  
Strain Hardening ◽  
Simple Shear ◽  
Linear Response ◽  
Polymer Melts ◽  
Molecular Model ◽  
Uniaxial Extension ◽  
Polymer Melt ◽  
Non Linear ◽  
Ldpe Melt ◽  
Made In

Abstract We present new non-linear data in extension and two different shear histories. These data are used to compare the effectiveness of using exponential shear data and uniaxial extension data to characterise the non-linear response of an industrial LDPE melt with the pom-pom molecular model. We conclude that extension and exponential shear both allow good predictions to be made in simple shear. However, the characterisation spectrum obtained from exponential shear data fails to predict the correct degree of strain hardening at low extension rates. From this study we are able to suggest circumstances under which exponential shear provides a useful characterisation of branched polymer melts.

An experimental study of exit pressures for polymer melts

1990 ◽  
Vol 29 (1) ◽  
pp. 60-70 ◽  
Author(s):  
T. W. Chan ◽  
B. Pan ◽  
H. Yuan
Keyword(s):  
Experimental Study ◽  
Polymer Melts

Experimental study of the deformed nucleus 153Sm via (d→,t) and average resonance capture as a test case for the multiorbit interacting boson fermion model

1998 ◽  
Vol 57 (6) ◽  
pp. R2781-R2785 ◽  
Author(s):  
A. Gollwitzer ◽  
R. Hertenberger ◽  
A. Metz ◽  
P. Schiemenz ◽  
B. Valnion ◽  
...  
Keyword(s):  
Experimental Study ◽  
Test Case ◽  
Resonance Capture ◽  
Fermion Model ◽  
Deformed Nucleus ◽  
Average Resonance

Multigranular Molecular Dynamics Simulations of Polymer Melts Using Multibody Algorithms

2005 ◽  
Author(s):  
Rudranarayan M. Mukherjee ◽  
Kurt S. Anderson ◽  
John Ziegler
Keyword(s):  
Molecular Dynamics ◽  
Polymer Melts ◽  
Parallel Implementation ◽  
Equations Of Motion ◽  
Low Frequency ◽  
Polymer Melt ◽  
Rigid Bodies ◽  
Computational Time ◽  
Integration Time ◽  
Test Case

In a multigranular approach for modeling molecular dynamics of polymer melts, different sections of the simulation box are modeled at different levels of detail viz. as particles, flexible bodies or rigid bodies. This approach eliminates high frequency localized motion while maintaining low frequency global conformational motion. This allows for longer integration time steps thus decreasing computational time. In this paper, we discuss our efforts to develop a consortium of dynamics algorithms capable of efficiently generating and solving the equations of motion at all three levels of modeling on a common software platform. A bead spring model of the polymer melt moving under the influence of truncated Lennard-Jones potential under periodic boundary conditions is pursued. Implementation issues and results from a test case consisting of 32 polymer chains of 16 beads each are presented. The paper also discusses the parallel implementation of this problem using MPI.

Molecular Drag-Strain Coupling in Branched Polymer Melts

2000 ◽  
Vol 629 ◽  
Author(s):  
Richard J. Blackwell ◽  
Tom C. B. McLeish ◽  
Oliver G. Harlen
Keyword(s):  
Branch Point ◽  
Polymer Melts ◽  
Uniaxial Extension ◽  
Extensional Viscosity ◽  
Low Density Polyethylene ◽  
Model Parameters ◽  
Low Density ◽  
Branch Points ◽  
Nonlinear Rheology ◽  
Branched Polymer

ABSTRACTThe “pom-pom” model of McLeish and Larson (J. Rheol. 42, 81, 1998) provides a simple molecular theory for the nonlinear rheology of long chain branched polymer melts. The Edwards-de Gennes tube concept is used to derive a constitutive equation for a simple branched molecule composed of two star polymers linked by a single backbone chain. A feature of this model is that the backbone section of tube can stretch up to maximum length given by the maximum entropic drag-force from the arms, after which the star arms are withdrawn into the backbone tube. This produces a sharp transition in the extensional viscosity at this maximum stretch. This unphysical feature results from an over-simplification of the behaviour near the branch points.In this paper we introduce a simple treatment of the coupling between relaxed and unrelaxed polymer segments at branch-points. This allows for localised displacements of branch-point within a quadratic potential before maximum extension is reached. Displacing the branch-point reduces the length of arm outside the tube and so reduces in the drag on the star arms. This smoothes out the sharp transitions in extensional viscosity in the original “pom-pom” model at the cost of introducing an extra unknown parameter.This modification improves the prediction of the nonlinear rheology of H-polymers whose molecular structure is known. Alternatively, for polymers of unknown structure such as commercial Low Density Polyethylene, the model parameters may be fitted from linear viscoelastic and uniaxial extension data, to provide predictions for the behaviour in transient nonlinear shear and planar extension. By including local branch-point displacement we find improved agreement with the data for Low-Density Polyethylene.

A new hyperbolic model and an experimental study for the flow of polymer melts in Multi-Pass Rheometer

2011 ◽  
Vol 44 (1) ◽  
pp. 258-266 ◽  
Author(s):  
Amr Guaily ◽  
Eric Cheluget ◽  
Karen Lee ◽  
Marcelo Epstein
Keyword(s):  
Experimental Study ◽  
Polymer Melts ◽  
Hyperbolic Model

Dynamics of Branched Polymer Melts in Complex Kinematics Flows: A Computational∕Experimental Study

2008 ◽  
Author(s):  
Arash Abedijaberi ◽  
Johannes Soulages ◽  
Hans Christian Öttinger ◽  
Martin Kröger ◽  
Bamin Khomami ◽  
...  
Keyword(s):  
Experimental Study ◽  
Polymer Melts ◽  
Branched Polymer
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