• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.281-282
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• 2006

Tension control performance is very important in high-speed printing machine. One of the major factors that effect to tension control performance is the process of roll changing. Even if the turret arm moves during roll changing process and the span length of the unwinding system varies, it is customary to neglect it in motion and tension control and to consider it as a disturbance. In this paper, its effect is modeled nonlinearly and compared with linear model, and an effect of an infeeder dancer is analyzed under the condition with no unwinder dancer. We verify the performance of the proposed method via simulation in the high-speed printing machine.

• 소성∙가공
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• 제32권2호
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• pp.87-91
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• 2023

In the present work, the ductile fracture behaviors of ultra-high strength steel sheets along the different loading directions are investigated under various loading paths. Three loading paths, i.e., in-plane shear, uniaxial tension, plane strain tension deformations, are considered, and the corresponding specimens are described. The experiments are conducted using the digital image correlation (DIC) system to analyze the strain at the onset of the fracture. The experimental results show that the loading path for each specimen sample is linear, and different values of the fracture strains for the loading direction from the plane strain tension are observed. The ductile fracture model of the modified Mohr-Coulomb (MMC) is constructed based on the experimental data and evaluated along the rolling direction and transverse direction under various loading paths.

• Journal of Biosystems Engineering
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• 제17권3호
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• pp.237-246
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• 1992

This study was conducted to investigate experimentally the effect of track tension on the tractive performance of rice combine. The experiment was carried out at the two in-door soil bins with soil types of loam and sandy loam. The initial track tension was varied by three different values of 0.71, 1.75 and 3.84kN at three different forward velocity settings of 0.17, 0.32 and 0.45m/s, respectively. The data acquisition system was designed and used for the measurement of pull, driving axle torque and its velocity under the test conditions to calculate the tractive efficiency. Results of the study were summarized as follows : 1) The effect of the initial track tension on the tractive efficiency was found being significantly dependent on soil types but not on forward velocities. Therefore, the benifit of adjusting the initial track tension may be obtained when the types of soils on which combines operate are changed. 2) In loam, tractive efficiency decreased with increase in track tension. However, it increased in sandy loam until it reached to a peak value and then decreased with increase in track tension. 3) The maximum tractive efficiency of the tested combine was obtained with an initial track tension of about 1.75kN on sandy loam, and below that on loam at about 5% slippage without being noticeably influenced by the forward velocity.

• Fibers and Polymers
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• 제5권4호
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• pp.275-279
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• 2004

Yarn tension is a key factor that affects the efficiency of a ring spinning system. In this paper, a specially constructed rig, which can rotate a yam at a high speed without inserting any real twist into the yarn, was used to simulate a ring spinning process. Yarn tension was measured at the guide-eye during the simulated spinning of different yarns at various balloon heights and with varying yarn length in the balloon. The effect of balloon shape, yarn hairiness and thickness, and yam rotating speed, on the measured yarn tension, was examined. The results indicate that the collapse of balloon shape from single loop to double loop, or from double loop to triple etc, lead to sudden reduction in yarn tension. Under otherwise identical conditions, a longer length of yarn in the balloon gives a lower yarn tension at the guide-eye. In addition, thicker yarns and/or more hairy yarns generate a higher tension in the yarn, due to the increased air drag acting on the thicker or more hairy yarns.

• Earthquakes and Structures
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• 제17권4호
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• pp.425-434
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• 2019

The most effective passive vibration control and seismic resistance options in a reinforced concrete (RC) high-rise building (HRB) are the base isolation and the tuned mass damper (TMD) system. Many options, which may be suitable or not for different soil types, with different types of bearing systems, like rubber isolator, friction pendulum isolator and tension/compression isolator, are investigated to resist the base straining actions under five different earthquakes. TMD resists the seismic response, as a control system, by reducing top displacement or the total movement of the structure. Base isolation and TMDs work under seismic load in a different way, so the combination between base isolation and TMDs will reduce the harmful effect of the earthquakes in an effective and systematic way. In this paper, a comprehensive study of the combination of TMDs with three different base-isolator types for three different soil types and under five different earthquakes is conducted. The seismic response results under five different earthquakes of the studied nine RC HRB models (depicted by the top displacement, base shear force and base bending moment) are compared to show the most suitable hybrid passive vibration control system for three different soil types.

• 에너지공학
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• 제13권4호
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• pp.235-241
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• 2004

본 연구는 초음파 개질 바이오 디젤유의 점도와 표면장력에 대한 연료의 물리적 특성, 분무 미립화 특성에 관한 심층적이고 체계적인 연구에 중점을 두었다. 이를 규명하기 위하여 초음파 재질 연료와 개질 되지 않은 연료의 상대 비교 분석을 통한 연료특성과 연료분사펌프의 회전수 및 노즐선단 거리변화에 의한 입경측정의 상관성을 정립하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.541-545
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• 1996

In this paper, The performance and functions of automatic flatness control system installed on the 4 hi-reversing mill and has been investigated under actualconditions. A new automatic flatness control system incorporates a measuring roll for measurement and correction calculations, hydraulic roll benders, selective roll cooling, and a programmable controller for interface and data logging. The test results are as following. The more the exit steel strip thickness is thick, the smaller the I value, and the more it is thin, the larger the I value. And, a complex distribution of strip tension was controlled, for example, not only a quarter buckle but also a simple center wave and edge wave. Because the tension deviation is larger at acceleration speed and deceleration speed than steady speed, so automatic flatness control system of contact type is better to adopt over 450 m/min, automatic flatness control system reduces rapidly large flatness deviation. The maximum I value of strip has been decreased to 13 I, and defects caused by poor flatness have been drastically decreased. And coolant temperature for work roll cooling system on the automatic flatness control system is better to adopt about 50-55 .deg. C.

• 한국정밀공학회지
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• 제13권5호
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• pp.67-73
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• 1996

The necessity for more accurate automatic flatness control(AFC) system has increased of customers' requirement for cold rolled steel sheet. Therefore, many cold rolling mills replaced its AFC system with a measuring roll of the contact type form the non-contact type. In this paper. The performance of AFC system of contact type has been investigated under industrial conditions. It has two kinds of actuator: roll bender, spot cooling system. The test results are as follows: The more strip thickness is thick, the smaller the I value, and the more it is thin, the bigger the I value. And a complex distribution of strip tension was controlled, for example, not only a pocket wave but also a simple center wave and edge wave. Because the tension deviation is larger at acceler- ation speed and decelerationspeed than steady speed, AFC system of contact type is better to adopt over 50m/mim. AFC system reduces rapidly large flatness deviation. The maximum I value of strip has been decreased to 13 I, and sticker, defects caused by poor flatness, have been decreased about 60%.

• 한국자동차공학회논문집
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• 제4권6호
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• pp.109-120
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• 1996

Serpentine belt drive system offers the advantages of light weigh, low cost, quientness, and efficiency. Since these belts are typically longer than conventional belts, a tensioner component is added to maintain acceptable belt tension levels and make no slippage between pulleys and belts. This paper addresses the modeling and analysis of the automotive belt drive systems and also addresses the predicton of slippage on rotational modes. Vibration characteristics are determined from the eigenvalue problem governing the free response. Under certain engine operating conditions, the dynamic tension fluctuations may be sufficient to cause the belt to slip on particular accessory pulleys, It is found that this slippage can be reduced by adding the tensioner component from the analysis of belt tension and belt compression.

• 한국해양공학회지
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• 제31권3호
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• pp.202-207
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• 2017

This paper presents the results of an experimental study on the motions and mooring characteristics of a floating vertical axis wind turbine system. Based on a comparison of regular wave experiment results, the motions of structures with different types of mooring are almost the same. Based on the tension response results of a regular wave experiment with a catenary mooring system, the mooring lines in front of the structure have a larger tension effect than the back of the structure by the drifted offset of the structure. The dynamic response spectrum of the structure in the irregular wave experiments showed no significant differences in response to differences in the mooring system. As a result of the comparison of the tension response spectra, the mooring lines have a larger value with a drifted offset for the structure, as shown in the previous regular wave experiment. The results of the dynamic response of the structure under irregular wave and wind conditions showed that the heave motion response is influenced by the coupled effect with the mooring lines of the surge and pitch motion due to the drifted offset and steady heeling. In addition, the mooring lines in front of the structure have a very large tension force compared to the mooring lines in back of the structure as a result of the drifted offset of the structure.