Molecular instabilities in capillary flow of polymer melts: Interfacial stick-slip transition, wall slip and extrudate distortion

1997 ◽  
Vol 198 (3) ◽  
pp. 673-701 ◽  
Author(s):  
Shi-Qing Wang ◽  
Patrick Drda
Keyword(s):  
Polymer Melts ◽  
Capillary Flow ◽  
Wall Slip ◽  
Stick Slip ◽  
Slip Transition ◽  
Extrudate Distortion

Extrusion of Polymer Melts and Melt Flow Instabilities. I. Experimental Study of Capillary Flow and Extrudate Distortion

1969 ◽  
Vol 42 (3) ◽  
pp. 675-681 ◽  
Author(s):  
Gene A. Bialas ◽  
James L. White
Keyword(s):  
Experimental Data ◽  
Polymer Melts ◽  
Capillary Flow ◽  
Flow Instability ◽  
Research Effort ◽  
Flow Instabilities ◽  
Melt Flow ◽  
Considerable Research ◽  
Extrudate Distortion ◽  
First Descriptions

Abstract The extrusion of molten plastics, elastomers and fibers represent an important industrial operation. The rate of extrusion of melts through dies is limited by the onset of a flow instability. This phenomenon consists of a change in flow from uniform to irregular that results in the production of rough and distorted extradates drastically different from the smooth cylinders obtained at lower rates. Extrusion melt flow instability is observed in the entire spectrum of polymer melts ranging from silicone gums through nylon and polyolefin plastics to raw elastomers. Since the first descriptions of this phenomena in the 1940's considerable research effort has been expended in this area with limited agreement. It is the purpose of part I to: (1) present new experimental data on capillary flow of polymer melts and extrudate distortion, and (2) to review critically the literature on extrudate distortion.

Wall slip and extrudate distortion of three polymer melts

2003 ◽  
Vol 47 (3) ◽  
pp. 683-699 ◽  
Author(s):  
Dilhan M. Kalyon ◽  
Halil Gevgilili
Keyword(s):  
Polymer Melts ◽  
Wall Slip ◽  
Extrudate Distortion

Wall slip and absence of interfacial flow instabilities in capillary flow of various polymer melts

1998 ◽  
Vol 42 (1) ◽  
pp. 63-80 ◽  
Author(s):  
Xiaoping Yang ◽  
Hatsuo Ishida ◽  
Shi-Qing Wang
Keyword(s):  
Polymer Melts ◽  
Capillary Flow ◽  
Wall Slip ◽  
Flow Instabilities ◽  
Interfacial Flow

Experimental Study of Rheological Characteristics of Polymer Melts in the Micro-Die

2012 ◽  
Vol 550-553 ◽  
pp. 716-723
Author(s):  
Tofek Abddiem ◽  
Da Ming Wu ◽  
Jian Zhuang ◽  
Li Jun Hou ◽  
Ying Liu ◽  
...  
Keyword(s):  
Experimental Study ◽  
Shear Rate ◽  
Polymer Melts ◽  
Capillary Flow ◽  
Slip Rate ◽  
Polymer Melt ◽  
Wall Slip ◽  
Rheological Characteristics ◽  
Capillary Rheometer ◽  
Measured Viscosity

Compared with in the conventional scales, the rheological properties of polymer melts have changed in the micro-scales. Based on the principle of capillary flow and modified with the method of Bagley or zero die micro-die, the rheological characteristics of polypropylene (PP) were investigated using the HAAKE capillary rheometer under the micro-die and conventional die. The results show that: the viscosity of polymer melt modified with the method of bagley or zero die micro-die in the different L/D ratio of micro-die is the same and the shear viscosity of PP decreases with the increase of shear rate; Compared with the viscosity in the conventional scales, the measured viscosity of PP in the micro-scales was reduced by 46% in 0.25mm diameter die, 44% in the 0.20mm diameter die and 88% in the 0.15mm diameter die at the same shear rate; a layer of fixed polymer melt was found in the inwall of the micro-die through the calculation of wall slip rate.

Experimental Investigation of Power Umbilical Damping

2017 ◽  
Author(s):  
Torfinn Ottesen
Keyword(s):  
Steady State ◽  
Energy Input ◽  
State Energy ◽  
Seawater Temperature ◽  
Structural Damping ◽  
Stick Slip ◽  
Slip Regime ◽  
Free Decay ◽  
Vortex Induced Vibrations ◽  
Slip Transition

Ocean currents may cause vortex induced vibrations (VIV) of deep-water umbilicals and cables. Since the VIV response may give significant contributions to the total fatigue damage it is important to know the structural damping for relevant curvature levels. A laboratory test has been performed on a 12.5 m long test specimen to determine the damping for a range of curvature levels that are in the vicinity of the stick-slip transition region. The energy input to maintain steady state oscillations with curvature amplitudes in the range 0.0002–0.001 m−1 was measured. The steady state energy input is consistent with damping ratios obtained using the free decay method. The structural damping depends on construction temperature and curvature and is less for typically low seawater temperature and low curvatures. The transition between the stick- and the slip regime is seen for typical seawater temperature.

Ultraslow frictional sliding and the stick-slip transition

2018 ◽  
Vol 113 (24) ◽  
pp. 241602 ◽  
Author(s):  
Alexander Breki ◽  
Michael Nosonovsky
Keyword(s):  
Stick Slip ◽  
Frictional Sliding ◽  
Slip Transition
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