Stress Relaxation in Polymer Melts Following Equibiaxial Step Strain

2010 ◽  
Vol 43 (13) ◽  
pp. 5874-5880 ◽  
Author(s):  
Teresita Kashyap ◽  
David C. Venerus
Keyword(s):  
Stress Relaxation ◽  
Polymer Melts ◽  
Step Strain

STRESS RELAXATION OF MAGNETORHEOLOGICAL FLUIDS

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2655-2661
Author(s):  
W. H. LI ◽  
G. CHEN ◽  
S. H. YEO ◽  
H. DU
Keyword(s):  
Stress Relaxation ◽  
Viscoelastic Model ◽  
Relaxation Modulus ◽  
Damping Function ◽  
Mr Fluids ◽  
Large Step ◽  
Linear Viscoelastic ◽  
Predicted Values ◽  
Two Parameters ◽  
Step Strain

In this paper, the experimental and modeling study and analysis of the stress relaxation characteristics of magnetorheological (MR) fluids under step shear are presented. The experiments are carried out using a rheometer with parallel-plate geometry. The applied strain varies from 0.01% to 100%, covering both the pre-yield and post-yield regimes. The effects of step strain, field strength, and temperature on the stress modulus are addressed. For small step strain ranges, the stress relaxation modulus G(t,γ) is independent of step strain, where MR fluids behave as linear viscoelastic solids. For large step strain ranges, the stress relaxation modulus decreases gradually with increasing step strain. Morever, the stress relaxation modulus G(t,γ) was found to obey time-strain factorability. That is, G(t,γ) can be represented as the product of a linear stress relaxation G(t) and a strain-dependent damping function h(γ). The linear stress relaxation modulus is represented as a three-parameter solid viscoelastic model, and the damping function h(γ) has a sigmoidal form with two parameters. The comparison between the experimental results and the model-predicted values indicates that this model can accurately describe the relaxation behavior of MR fluids under step strains.

scholarly journals Dynamics and stress relaxation of bidisperse polymer melts with unentangled and moderately entangled chains

2021 ◽  
Vol 33 (6) ◽  
pp. 063105
Author(s):  
Oluseye Adeyemi ◽  
Shiping Zhu ◽  
Li Xi
Keyword(s):  
Stress Relaxation ◽  
Polymer Melts

Significance of cross correlations in the stress relaxation of polymer melts

2007 ◽  
Vol 126 (24) ◽  
pp. 244904 ◽  
Author(s):  
Jorge Ramírez ◽  
Sathish K. Sukumaran ◽  
Alexei E. Likhtman
Keyword(s):  
Stress Relaxation ◽  
Polymer Melts ◽  
Cross Correlations

Stress Relaxation Behavior of Catheter Reinforced with Braid under Combined Loading for Bending and Torsion

2013 ◽  
Vol 372 ◽  
pp. 261-264 ◽  
Author(s):  
Yasuyuki Kato ◽  
Masahito Ueda
Keyword(s):  
Stress Relaxation ◽  
Principal Axis ◽  
Physical Property ◽  
Combined Loading ◽  
Two Stage ◽  
Relative Angle ◽  
Coefficient Of Viscosity ◽  
Relationship Of ◽  
The Relationship ◽  
Step Strain

The purpose of this research is to examine the physical property of the catheter, which made of soft nylon resin and is reinforced with thin stainless wires called braid. The effect of braid on the mechanical property of the catheter is revealed by investigating the relationship of the stress relaxation and the relative angle between the braid and the principal axis of stress under combined loading of bending and torsion. Inthe first place, in order to investigate the phenomenon of stress relaxation under combined loading, the experiments under single stage step strain have been carried out by changing the ratio of bending and torsion, and the relation between the coefficient of viscosity and the relative angle of the braid is revealed. In the second place, the experiment under two-stage step strain are conducted by changing the order of bending and torsion, and the effect of these loading histories on the visco-elastic properties is examined. Moreover, the numerical simulation under two-stage step strain is carried out by using the estimated coefficient of viscosity, and in this paper, the validity of this analytical model is confirmed by comparing with the experimental results.

Arm-Length Dependence of Stress Relaxation in Star Polymer Melts

1998 ◽  
Vol 31 (21) ◽  
pp. 7479-7482 ◽  
Author(s):  
S. T. Milner ◽  
T. C. B. McLeish
Keyword(s):  
Stress Relaxation ◽  
Polymer Melts ◽  
Star Polymer ◽  
Length Dependence
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