• 한국소음진동공학회논문집
• /
• 제25권12호
• /
• pp.874-880
• /
• 2015

This paper presents the vibration analysis of a deploying beam with spin when the beam has a time-dependent spinning speed. In the previous studies for the deploying beams with spin, the spinning speed was time-independent. However, it is more reasonable to consider the time-dependent spinning speed. The present study introduces the time-dependent spinning speed in the modeling. The Euler-Bernoulli beam theory and von Karman nonlinear strain theory are used together to derive the equations of motion. After the equations of motion are transformed into the weak forms, the weak forms are discretized. The natural frequency and dynamic response are obtained. The effect of the time-dependent spinning speed on the dynamic response is studied.

• Fibers and Polymers
• /
• 제3권1호
• /
• pp.18-23
• /
• 2002

The structure development and dynamic properties of fibers produced by high-speed spinning of P(EN-ET) random copolymers were investigated. The as-spun fibers were found to remain amorphous up to the spinning speed of 1500 m/min, and subsequent increases in speed resulted in the crystalline domains containing primarily $\alpha$ crystalline modification of PEN. The f modification was not found up to spinning speeds of 4500 m/min. On the other hand, annealing of constrained fibers spun at the 2100 m/min at 180,200, and 240^{\circ}C$ exhibited $\beta$-form crystalline structure, while the annealed fibers spun in 600-1500 m/min range exhibited dominantly $\alpha$-form. However $\beta$-form crystals disappeared above the spinning speed of 3000 m/min. With increasing spinning speeds from 600 to 4500 m/min, the storage modulus of as-spun fibers increased continuously and reached a value of about 10.4 spa at room temperature. The tan $\delta$curves showed the $\alpha$-relaxation peak at about 155-165^{\circ}C$, which is considered to correspond to the glass transition. The $\alpha$-relaxation peaks became smaller and broader, and shift to higher temperatures as the spinning speed increases, meaning that molecular mobility in the amorphous region is restricted by increased crystalline domain.

• 한국산업융합학회 논문집
• /
• 제2권1호
• /
• pp.27-33
• /
• 1999

Effects of spinning speed and draw ratio on structure and mechanical properties of PP filament. A The crystalline structure and mechanical properties of uniaxially deformed polypropylene filament has been examined by XRD, birefringence, UTM and density method. Uniaxially deformed PP filament was prepared of various spinning speeds (300, 600, 900m/min.) and draw ratio(x2, x3, x4). From the results of these studies, it found the following facts. Firstly, it was found that the crystallinity and crystallite size (110plane) of the samples were increased with increasing of spinning speed and draw ratio, especially, it was rapidly increased between as spun yarn and 2 times draw ratio. Secondly, birefringence value was increased with increasing of spinning speed and draw ratio. The mechanical properties of initial modulus, tensile strength were increased with increasing of spinning speed and draw ratio also, but the degree of elongation decreased as spinning speed and draw ratio.

• 한국염색가공학회지
• /
• 제6권4호
• /
• pp.34-39
• /
• 1994

For the purpose of obtaining high modulus PET tire cord fiber by high spinning speed, the change of initial modulus and taut tie molecules (T.T.M) fraction with the PET tire cord fibers by different spinning speed is investigated. Initial modulus decreased with increasing spinning speed but increased above spinning speed of 1500m/min. Therefore, high modulus PET tire cord fiber may be obtained above spinning speed of 3500m/min. It was found that the initial modulus of fibers depends on fraction of T.T.M.

• 한국공작기계학회논문집
• /
• 제14권4호
• /
• pp.89-95
• /
• 2005

This paper intends to identify experimentally the relationship between transverse vibration behavior of a spinning disk and high-frequency fluctuation in the driving torque. A testrig has been developed using a CD-ROM disk, a driving motor with torque-varying capability and a power transmission belt and a laser vibrometer was employed to measure the transverse vibration displacements of the disk for a certain range of the spinning speed. The results show that the spinning speed and the magnitude and frequency of the torque fluctuation affect the stability of the disk. In other word, the torque fluctuation causes the instability of the disk at several ranges of the spinning speed below the critical speed and its effects become larger as the disk spins faster or the magnitude of torque fluctuation becomes bigger. The experimental results are found to be in good agreement with analytical estimation.

• 한국의류학회지
• /
• 제30권4호
• /
• pp.607-614
• /
• 2006

This study was carried out to suggest the optimal spinning process condition which provides a proper range of tenacity and biodegradability as textile fibers. The effects of the melt spinning speed and heat treatment on the mechanical property and biodegradability of polylactic acid fiber were investigated. Polylactic acid(PLA) was spun in a high spinning speed of $2000{\sim}4000m/min$. Each specimen was heat-treated at $100^{\circ}C$ during 30min. Mechanical properties such as breaking stress and the degree of crystallinity were evaluated using WAXS. Biodegradability was estimated from the decrease of breaking stress, weight loss, and the degree of crystallinity after soil burial. Experimental results revealed that heat treated specimens showed higher breaking stress than untreated specimens, but the increase was not so high as was expected from the remarkable change of crystallinity by heat treatment. It was concluded that breaking stress was more influenced by spinning speed than heat treatment. In the soil burial test, however biodegradability calculated from weight loss was more influenced by heat treatment than spinning speed.

• Bulletin of the Korean Chemical Society
• /
• 제31권11호
• /
• pp.3252-3258
• /
• 2010

In this study, the effects of the various parameters of spinning and drawing processes on the properties of polyester full drawn yarn (FDY) prepared by steam processing during high-speed spinning were investigated using several techniques. The wet shrinkage ratio of the FDY was able to be manipulated by controlling the temperature and draw ratio. The FDY made using the steam high speed spinning technique exhibited identical properties (such as tenacity, elongation, and wet shrinkage ratio) to that of regular FDY, made using the spin-draw process. FDY prepared using the steam process during high-speed spinning showed excellent dyeability. The dye pick-up of the polyester yarn spun at high-speed spinning was found to be improved when dyed under an atmospheric pressure of $100^{\circ}C$. This result was the same as regular FDY dyed under a high pressure of $130^{\circ}C$.

• 한국염색가공학회지
• /
• 제8권6호
• /
• pp.33-39
• /
• 1996

The purpose of this study was to investigate the structural characteristics, mechanical properties, and stress-relaxation behavior of PET filament, which were prepared at various spinning speeds(1650, 3300, 4500, 5000, 5500, and 6000 m/min) and anneal(12$0^{\circ}C$, 20 min & 15$0^{\circ}C$, 40 min). In 4500 m/min of spinning speed the crystallinity, crystallite size, and degree of orientation of PET filament rapidly increased. By increasing spinning speed, the temperature dependence of stress-relaxation sharply decreased. Same results were obtained from heat-treated samples. As a result, activation energy for stress-relaxation increased with the crystallinity and spinning speed.

• 청정기술
• /
• 제15권4호
• /
• pp.245-252
• /
• 2009

Poly(lactic acid) (PLA) 용융방사공정의 속도, 직경, 온도, 인장응력 분포를 구하기 위해 수치모사를 실시하였다. 유한차분법을 이용하여 반지름 방향으로의 온도분포곡선을 구하였다. 방사속도 1 km/min에서 5 km/min까지 방사속도에 따른 PLA 방사공정의 변화와 poly(ethylene terephthalate) (PET)와의 거동을 비교해 보았고, 방사공정변수가 섬유 중심부와 표면과의 온도차에 미치는 영향을 살펴보았다. PLA는 용융온도가 PET에 비해 낮음에도 불구하고 동일 방사조건에서 더딘 냉각속도를 보였고 방사거리에 따른 방사속도의 증가도 PET가 더 빠른 양상을 나타내었다. PLA의 섬유중심부와 섬유표면과의 온도차는 약 4.6 K에 이르렀는데, 이는 PET의 10.4 K에 비하여 낮은 값이다. PLA 섬유중심부와 표면과의 온도차는 냉각풍속도와 방사온도가 증가할수록 증가하였고, 냉각풍 온도가 감소할수록 증가하는 경향을 나타내었다.

• 한국염색가공학회지
• /
• 제14권4호
• /
• pp.197-207
• /
• 2002

The physical properties and dyeability of the nylon 6 fibers prepared by high speed spinning at take-up speed of 4,100~5,600m/min were investigated. The strain decreased as the take-up speed was raised from 4,100m/min to 4,400m/min, but further increase of take-up speed could not decrease the strain. The stresses of the fibers spinned at various take-up speed did not make any noticeable differences. Birefringences, densities and crystallinities of the fibers increased with the take-up speed and then reached to a nearly maximum value at 5,300m/min. In DSC diagrams, the $\gamma$ form of crystal became dominant at higher take-up speed. The dye uptakes of C. I. Acid Blue 113 on the fibers decreased a little with the increase of take-up speed.