Relaxation changes in polyacrylonitrile yarn during the heat-stretching process

1990 ◽  
Vol 21 (6) ◽  
pp. 482-484
Author(s):  
B. A. Fomenko ◽  
M. V. Rumyantseva ◽  
�. A. Pakshver ◽  
Yu. A. Tolkachev
Keyword(s):  
Polyacrylonitrile Yarn ◽  
Stretching Process

High-elasticity and tensile properties of polyacrylonitrile yarn in the stretching process

1980 ◽  
Vol 11 (4) ◽  
pp. 284-287
Author(s):  
V. D. Fikhman ◽  
B. V. Radushkevich ◽  
V. P. Napasnikov
Keyword(s):  
Tensile Properties ◽  
High Elasticity ◽  
Polyacrylonitrile Yarn ◽  
Stretching Process

The Applications of Vibratory Stress Relief in High-Strength Aluminum Alloy Thick Plate

2012 ◽  
Vol 430-432 ◽  
pp. 881-885
Author(s):  
Cai Jun Gan ◽  
Kai Liao
Keyword(s):  
Aluminum Alloy ◽  
Residual Stresses ◽  
Dimensional Stability ◽  
Strain Energy ◽  
Thick Plate ◽  
High Strength ◽  
Stress Relief ◽  
High Strength Aluminum Alloy ◽  
Mechanical Stretching ◽  
Stretching Process

The level and distribution of residual stresses have great impact on dimensional stability, while Vibratory Stress Relief (VSR) is an effective technology to relax or homogenize residual stresses. Experimental study on residual stresses distribution, residual strain energy and machining deformation of 7075 high-strength aluminum alloy thick plate under different aging process status shows that VSR can effectively decrease the amplitude and strain energy density, and enhance stability of dislocation structures and phase states in metal microscopic volume, then internal residual stresses are homogenized to enhance components’ anti-deformation capacity. In addition, the capability in maintaining dimensional stability from VSR is better than that from traditional mechanical stretching process

scholarly journals Influence of annealing on the polycarbonate stretching process

2014 ◽  
Author(s):  
A. Wibbeke ◽  
A. Göttlicher ◽  
V. Schöppner
Keyword(s):  
Stretching Process

Laws governing the stretching of preliminarily oriented polyacrylonitrile yarn

1989 ◽  
Vol 20 (4) ◽  
pp. 267-270
Author(s):  
B. A. Fomenko ◽  
�. A. Pakshver ◽  
M. V. Rumyantseva ◽  
Yu. A. Tolkachev ◽  
E. P. Krasnov
Keyword(s):  
Polyacrylonitrile Yarn

Promotion of polysulfone membrane by thermal-mechanical stretching process

2013 ◽  
Vol 20 (3) ◽  
Author(s):  
Farzaneh Mahmoudi ◽  
Ehsan Saljoughi ◽  
Seyed Mahmoud Mousavi
Keyword(s):  
Polysulfone Membrane ◽  
Mechanical Stretching ◽  
Stretching Process

Physical properties of biaxially oriented PA6 film for simultaneous stretching and sequential processing

2011 ◽  
Vol 31 (1) ◽  
Author(s):  
Masao Takashige ◽  
Toshitaka Kanai
Keyword(s):  
Impact Strength ◽  
Physical Properties ◽  
Physical Property ◽  
High Impact ◽  
Thermal Shrinkage ◽  
Double Bubble ◽  
Biaxial Stretching ◽  
High Impact Strength ◽  
The Difference ◽  
Stretching Process

Abstract There are two different stretching processes that produce the biaxially oriented film, namely the tenter process and double bubble tubular film process. Furthermore, there are two tenter processes, i.e., the sequential biaxial stretching process and simultaneous biaxial stretching process. There is no report describing the difference among film physical properties of the three different processes. The biaxially oriented polyamide film using the double bubble tubular process has good balanced physical property and high impact strength, thus it is used for proper applications utilizing their advantage properties. In this report, the influence of each biaxial stretching process on film physical properties of polyamide, which has hydrogen bond, was studied in detail. As a result, the tentering process film has anisotropic tensile properties between machine direction (MD) and transverse direction (TD). This result was influenced by a later stretching process, namely TD stretching. On the contrary, the double bubble tubular film has good balanced properties, especially thermal shrinkage and impact strength. Tentering simultaneous stretching film has much larger shrinkage in MD than in TD. The sequential stretching film has larger shrinkage in TD than in MD. The double bubble tubular film has high impact strength, because it corresponds to the balanced molecular orientation.

scholarly journals Identification of the Process of Dynamic Stretching of Threads in Warp Knitting Technology Part II: Experimental Identification of the Process of Stretching Threads, with Verification of Rheological Models

2018 ◽  
Vol 18 (1) ◽  
pp. 1-6
Author(s):  
Aleksandra Prążyńska ◽  
Zbigniew Mikołajczyk
Keyword(s):  
Standard Model ◽  
Theoretical Analysis ◽  
Theoretical Data ◽  
Dynamic Processes ◽  
Rheological Models ◽  
Zener Model ◽  
Measuring Device ◽  
Experimental Identification ◽  
Research Material ◽  
Stretching Process

Abstract The study is a continuation of the first part of the publication, concerning the theoretical analysis of sensitivity of rheological models of dynamically stretched thread. This part presents the experimental research on the characteristics of stretching forces as a function of time, in the context of comparing the obtained results with theoretical data. The selected research material was three types of polyester silk threads with linear densities 84, 110 and 334 dtex. During the tests, threads of 400 to 1300 mm were stretched at speeds in the range of V ∈ [0.65, 1.47] m/s, which corresponds to the knitting speed n ∈ [700, 1600] courses/min. An original measuring device for empirical identification of dynamic processes of threads stretching was used during the tests. In total, 36 tests variants were performed. The procedures of mathematical equivalence were also worked out for the rheological models of Kelvin-Voigt, Zener and the three-parameter Standard model 2, which enabled the description of threads stretching phenomena in technological processes with the help of generalized rheological model, taking into account the visco-elastic qualities of threads. Experimental results showed that for the assumed deformation speeds ε(t) ∈ [0.53, 4.00] 1/s, the open three-parameter models – Standard model 2 and Zener model most reliably describe the stretching process.

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