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Volume 16, Issue 3
Displaying 1-4 of 4 articles from this issue
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Gen-ichi Yoshimura, Nobuo Iwaki, Sukenori Shintaku, Teruhiko Takayama1970 Volume 16 Issue 3 Pages 77-87
Published: 1970
Released on J-STAGE: October 24, 2006
JOURNAL FREE ACCESSThis article analyzes a covered yarn, which consists of a core spandex yarn and an untwisted continuous viscose rayon yarn and discusses its mechanical properties by varying draft ratio, feed velocity, denier of core yarn and number of winds of covering yarn during the covering process. The helix angle θ can be determined by the above conditions.
If the tension applied to the covered yarn during the covering process is removed, the covered yarn shrinks and reaches equilibrium state. The helix angle θb after shrinkage is determined by the initial helix angle θa in the covering process. The relation between θa and θb is induced.
The formula on the breaking elongation of the covered yarn can also be deduced if the breaking elongation of spandex and viscose yarn is known.View full abstractDownload PDF (1404K) -
Yoshiki Yanagawa, Sueo Kawabata, Hiromich Kawai1970 Volume 16 Issue 3 Pages 88-99
Published: 1970
Released on J-STAGE: October 24, 2006
JOURNAL FREE ACCESSThe biaxial tensile property of warp knitted fabric of single tricot stitch with close lap has been calculated theoretically from yarn properties and fabric structure, by using the method introduced by Kawabata. In this analysis, two regions, i.e., the deformation regions of bended yarn and yarn stretching, are separated with a critical stretch ratio taken as a border and the properties in these regions are analyzed separately. Then the properties in these two regions are composed. That is:
1. Calculating method of critical stretch ratios is introduced theoretically from fabric structure by putting a model in which yarn is straight and not stretched.
2. The biaxial tensile properties in the bending effective region is calculated from fabric structure and the equilibrium of forces, assuming that the unit structure consists of three arcs in relaxed form and that friction between yarns can be neglected.
3. Next, the biaxial tensile properties in the stretch effective region is calculated from the equilibrium of forces and the tensile property of yarn on assumption that yarn does not move from needle loop to sinker loop.
4. Finally, some examples are calculated and examined the effects of some structure constants of the fabric on its tensile property.View full abstractDownload PDF (1471K) -
Masao Chifu1970 Volume 16 Issue 3 Pages 100-107
Published: 1970
Released on J-STAGE: October 24, 2006
JOURNAL FREE ACCESSA high-frequency, responsive-force gauge is needed to observe the actual stress-strain curves of filament yarns in an extreme short loading time ranging in ms during high-speed testing.
A standstill indication of the force-gauge must be formed with the D.C out-put, because dead loads are charged to calibrate the gauge with weights.
The force gauge of a yarn-measuring instrument must have temperature stability and zero-level stability.
We have designed and built a high-frequency, responsive-force gauge with which to investigate the mechanical behavior of a filament yarn. The gauge is based on the principle that the frequency of a zero temperature coefficient (A.T Type) quartz crystal resonator of radio frequency shifts under external pressure.
The characteristics of the quartz crystal resonator force gauge show that the frequency response is from D.C to about 6-7KHz and stable both in the initial drift and temperature drift.
Further work is in progress to improve the mechanism of the force gauge so as to obtain a higher response.View full abstractDownload PDF (1756K) -
Kiyoji Nakamura, Akira Horikawa1970 Volume 16 Issue 3 Pages 108-113
Published: 1970
Released on J-STAGE: October 24, 2006
JOURNAL FREE ACCESSThe authors have looked into pressure drops in horizontal and vertical straight conveyor pipes and horizontal bent conveyor pipes to obtain basic data for use in designing a pneumatic conveyor system for fiber assemblies which will help forward the modernization of the spinning process.
The concept of friction velocity uf has been applied to the pneumatic conveyance of fiber assemblies to show that the ratio u/uf of mean air velocity u to uf is linearly correlated to the mixing ratio (weight) m; and that frictional coefficients Λ and Λ' of fluid for mixed-phase flow (air and fiber assembly) can be obtained.
The friction coefficient for a horizontal straight conveyor pipe is as given in eq. (15) Λ=8/(√<8/λ-5.10m>)2……(15)
The friction coefficient for a vertical straight pipe is as given in eq.(29) Λ'=8/(0.95√<8/λ-12.5m>)2……(19) The coefficient of the pressure drop in a horizontal bent pipe has been calculated by it into ξ for air flow and ζ which increases as a fiber assembly is added to, and the following equation has been obtained: ζ=0.112R/D(m-0.10)……(43)View full abstractDownload PDF (646K)
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