• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.9
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• pp.977-982
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• 2011

The horizontal force acting on a work roll was examined. This force results from the contact force between the work roll and backup roll in a backup-roll-drive 4-high cold-rolling mill. This horizontal force bends the work roll horizontally and therefore exerts reciprocal action on the roll-gap contour. An analytical model for predicting the horizontal force acting on a work roll, which generates a mean value in the steady state, was presented. The material used for the analysis was high-silicon steel (about 3% Si). A three-dimensional finite element (FE) model was also employed to investigate the non-steady-state behavior of the horizontal force. Results showed that the horizontal force varied with the off-center distance between the work roll and backup roll. In addition, the optimal off-center distance was determined to minimize the horizontal force.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.131-137
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• 2014

The SUV has a risk of rollover because of the highness of center of mass. In this paper the roll-behavior of a SUV in turning motion is analyzed. Dynamic model of the vehicle on the slope is developed and simulation is carried out using the software ADAMS/Car. The results show that the relational expression between the ground force acting on the tire and the roll motion is well established. It is also identified that the driving state of the vehicle becomes unstable at the lower or upper position of the slope.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1255-1260
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• 2012

The densification behavior of titanium powder in the direct powder rolling process was investigated. An analytical model for the roll-backlash phenomenon during this process was proposed to conduct a realistic finite element analysis. Furthermore, the roll-backlash was quantitatively analyzed, and the relative densities of the greenstrip along the rolling direction were precisely estimated. Finally, the slip and nip phenomena were identified by calculating the contact pressure and shear stress between the titanium powder and the roller in order to understand the densification behavior of the powder during the rolling process.

• Journal of the Korea Society for Simulation
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• v.28 no.2
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• pp.131-137
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• 2019

The operation of the precision-guided missiles with seekers is becoming more and more dominant since the modern wars became geographically localized like anti-terror campaigns and civil wars. Imaging seekers are relatively low-price and applicable to various operational conditions. The image tracker, however, requires highly advanced method for the target tracking under harsh missile flight condition. Missile roll can reduce the tracking performance since it introduces big differences in imagery. The missile roll is inevitable because of the disturbance and flight control error. Consequently, the errors of the subsystems should be under control for the stable performance of the tracker and the whole system. But the performance prediction by some simple metric is almost impossible since the target signature and the tracker are highly nonlinear. We established M&S tool for a precision-guided missile with imaging seeker and analyzed the roll effects to tracking and system performance. Furthermore, we defined the specification of missile subsystems through error analysis to guarantee system performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.485-486
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• 2007

• Polymer(Korea)
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• v.35 no.6
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• pp.574-579
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• 2011

3-Roll coating process as a key application technology for manufacturing automotive pre-painted metal-sheets has been studied. The 3-Roll coating system for this study consists of pick-up roll for picking up and distributing coating liquid from the reservoir, metering roll to properly meter coating liquid in metering gap regime, and applicator roll for directly transferring liquid into metal-sheet surface. Flow dynamics and operable coating windows of a polymeric paint (primer) with shear-thinning rheological property have been correlated with processing parameters such as speed ratio and metering gap between pick-up and metering rolls. In the uniform coating regime, dry coating thickness increased with increasing metering gap or decreasing speed ratio. Ribbing and cascade instabilities were observed in low speed and high speed ratio conditions, respectively. It is revealed that lower speed ratio makes severity and wavelength of the ribbing increase, aggravating flow instability in coating systems.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.195-202
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• 1999

The kinematic and complicance characteristics of torsion beam axle is structurally related to the location and section profile of torsion beam and the span from body mounting point to wheel center. This paper presents the effect of section properties in torsion beam on the structural characteristics and roll behavior of suspension. The structural characteristics is on the maximum stress on the welding area of torsion beam and the roll behavior is on roll steer and roll-camber of suspension which are important for controllability and stability in cornering. Four factors are used for the section design of torsion beam, which are thickness , midline length, are inner radius, and sector half angle . Through the structural and quasi-static analysis made for six torsion beam axle models, it can be noticed that roll steer and the structural durability of suspension are closely related to warping constant and shear center in section properties of torsion beam.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.77-80
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• 2002

드래프팅은 staple yarn의 생산에 있어 대단히 중요한 조작이다. 이 조작은 여러단계의 방적공정에서 반복 수행되며 각 공정에서 다음 공정에 적합하도록 두께를 가늘게 하고 집속체의 불균제를 최소화하여 제품의 품질을 결정하는데 그 중요한 역할을 한다. 지금까지 드래프트 전후의 슬라이버 상태에 관한 연구는 많이 이루어져 왔지만, 드래프트 존 내의 슬라이버의 동적거동에 대한 모델 연구는 아직 미흡한 실정이다. (중략)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.803-804
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• 2009

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.2
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• pp.271-277
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• 2013

Skin pass rolling is a very important process for applying a certain elongation to a strip in the cold rolling and annealing processes, which play an important role in preventing the stretching of the yield point when the material is processed. The exact prediction of the rolling force is essential for obtaining a given elongation with the steel grade and strip size. Unlike hot rolling and cold rolling, skin pass rolling is used to apply an elongation of within 2% to the strip. Under a small reduction, it is difficult to predict the rolling force because the elastic deformation behavior of the rolls is complicated and a model for predicting the rolling force has not yet been established. Nevertheless, the exact prediction of the rolling force in skin pass rolling has gained increasing importance in recent times with the rapid development of high-strength steels for use in automobiles. In this study, the possibility of predicting the rolling force in skin pass rolling for producing various steel grades was examined using foil rolling theory, which is known to have similar elastic deformation behavior of rolls in the roll bite. It was found that a noncircular arc model is more accurate than a circular model in predicting the roll force of high-strength steel below TS 980 MPa in skin pass rolling.