• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2000년도 춘계학술대회논문집
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• pp.44-47
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• 2000

In industrial practice caliber design in shape rolling depends on the designer's experience which in general is obtained through costly trial-and error process. Demonstrated in this paper is an application of the finite element method to the determination of optimal caliber shapes in shape rolling of LM-Guide.

• 전기학회논문지
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• 제67권5호
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• pp.663-668
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• 2018

A combined CPG (Central Pattern Generator) based foot trajectory and GA (Genetic Algorithm) based joint compensation method is presented for adaptive humanoid walking. In order to increase an adaptability of humanoid walking for rough terrains, the experiment for rolling terrains are introduced. The CPG based foot trajectory method has been successfully applied to basic slops and variable slops, but has a limitation for the rolling terrains. The experiments are conducted in an ODE based Webots simulation environment using humanoid robot Nao to verify a stability of walking for various rolling terrains. The proposed method is compared to the previous CPG foot trajectory technique and shows better performance especially for the cascade rolling terrains.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
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• pp.98-106
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• 1999

In this study cold rolling process for the irregular cross-sectional shape has been investigated. The product analyzed in present study is the steel cutter, which is frequently used to cut the desired shape on leather. Because steel cutter always has a irregular cross-section, after rolling process the workpiece is severely bended to every direction. The bending of the workpiece affects the processed performed after rolling such as heat treatment and grinding, then that of the workpiece becomes more severe. In this study, therefore, to prevent the bending of the workpiece to the left and right sides. rigid-plastic finite element method has been utilized and in order to find optimal roll geometry rapidly, one dimensional equal interval search technique has been also introduced. By using both rigid plastic finite element method and optimum technique, cold rolling process for the irregular cross-sectional shape has been successfully investigated.

• 유통과학연구
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• 제18권7호
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• pp.63-72
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• 2020

Purpose: This study examines the market segmentation and strategy of PT INKA, a rolling stock manufacturer in Indonesia. Research design, data and methodology: The study used the MCDM (Multiple Criteria Decision Making) method specifically the AHP (Analytical Hierarchy Process). The AHP method was applied to identify the target market. This method or approach considers the market attractiveness and competitive strength criteria with quantified parameters. Results: a) Australia, Kenya, Tanzania, New Zealand, and India emerge as the top five target markets; b) There is justification for rolling stock manufacturers to allocate their resources in winning the market share. Conclusion: The main challenge confronting the rolling stock manufacturer is limited resources to acquire a particular market share despite abundant opportunities in this sector. Despite the mastery of technology and long experience in the industry, selecting a target market with multiple criteria could be difficult for an emerging rolling stock manufacturer in South East Asia.

• 한국CDE학회논문집
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• 제2권2호
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• pp.122-129
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• 1997

Ball rolling blending is a popular technique for blending between parametric surfaces. The ball rolling blend surface is conceptually a trajectory of a ball rolling between two base sufaces. It is constructed by sweeping a circular arc along a ball contact curve pair. Since a ball rolling blend surfaces does not have a polynomial form like a Bezier surface patch, it is impossible to apply this method directly to a commercial CAD/CAM system. In this paper an algorithm is developed to approximate a ball rolling blend surface into Bezier surface patches. Least square method is applied to obtain proper Bezier surface patches under a given tolerance. The Bezier surface patches have degree three or more and guarantee VC1-continuity.

• 대한기계학회논문집
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• 제14권5호
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• pp.1155-1165
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• 1990

본 연구에서는 롤압력과 롤토크를 예측하는 새로운 방법이 제시된다. 이 방 법은 롤 간극에서의 자세한 변형도속도의 분포를 예측할 수 있으며, 특히 롤압력과 롤 토크의 계산에 필요한 유동응력 분포도 계산할 수 있다. 이 방법을 이용하여 압연조 건과 재료성질이 롤압력, 압하력, 롤토그 등에 미치는 영향을 조사하였다. 또한, 이 방법에 의해서 예측된 결과를 참고문헌과 포항제철의 공정 데이터로부터 발췌한 실험 데이터와 비교하였으며, 유한요소 해석결과와도 비교하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.95-98
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• 2008

In the present work, cross-roil rolling was rallied out using a rolling mill in which the roll axes are tilted by $5^{\circ},\;7.5^{\circ},\;10^{\circ}$ towards the transverse direction of the roiled sample. The evolution of strain states during cross-roll rolling was investigated by three-dimensional finite element method (FEM) simulation. Parallel to cross-roll rolling, normal-rolling using a conventional rolling mill was also carried out in the same rolling condition for clarifying the effect of cross-roll rolling. It turned out that three shear rate components were all introduced to the rolled sample by the cross-roll rolling process, while only one shear rate component operated during normal-rolling.

• Nuclear Engineering and Technology
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• 제51권8호
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• pp.1886-1896
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• 2019

Modern small modular nuclear reactors can be built on a barge in ocean, therefore, their flow characteristics depend upon the ocean motions. In the present research, effect of rolling motion on flow and friction characteristics of laminar flow through vertical and horizontal narrow channels has been studied. A computer code has been developed using MPS method for two-dimensional Navier-Stokes equations with rolling motion force incorporated. Numerical results have been validated with the literature and have been found in good agreement. It has been found that the impact of rolling motions on flow characteristics weakens with increase in flow rate and fluid viscosity. For vertical narrow channels, the time averaged friction coefficient for vertical channels differed from steady friction coefficient. Furthermore, increasing the horizontal distance from rolling pivot enhanced the flow fluctuations but these stayed relatively unaffected by change in vertical distance of channel from the rolling axis. For horizontal narrow channels, the flow fluctuations were found to be sinusoidal in nature and their magnitude was found to be dependent mainly upon gravity fluctuations caused by rolling.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.226-228
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• 2007

During asymmetrical cold rolling in AA 5052 sheet a reduction per a rolling pass was varied to investigate the effect of the ratio of the contact length between the roll and sample ($l_c$) to the sheet thickness (d) on the formation of shear textures. In order to intensify the shear deformation during asymmetrical rolling, AA 5052 sheet was asymmetrically cold rolled without lubrication by using different roll velocities of upper and lower rolls. Asymmetrical rolling with $l_c$/d=1.8 led to the formation of texture gradients throughout the sheet thickness in which the outer thickness layers depicted shear textures and the center thickness layers displayed a rolling texture. Asymmetrical rolling with $l_c$/d=3.1 gave rise to the formation of shear textures in the whole through-thickness layer. The strain states associated with asymmetrical rolling were investigated by the finite element method (FEM) simulation. FEM results indicated that the evolution of deformation texture in a thickness layer is strongly governed by integrated values of strain rates and along the streamline in the roll gap.

• Journal of Mechanical Science and Technology
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• 제18권5호
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• pp.762-769
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• 2004

An analytical approach is presented to investigate the deformation characteristics of billets in a continuous billet mill using power driven horizontal stands and idle vertical stands. The analysis is validated by comparison to the experimental results in a previously published work. The analytical results have shown that, apart from the problems of slip and buckling of billet, there are some shortcomings involved in this method. Compared to conventional rolling with all driven stands, the roll load for idle vertical stands and the rolling torque for horizontal stands are almost doubled. The billet is severely stressed within the roll-bite of idle vertical stands and the overall rolling power has increased by one third of that for conventional rolling. Theseshortcomings impair the feasibility of industrial application of idle vertical stand rolling method.