• 소성∙가공
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• 제23권1호
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• pp.5-9
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• 2014

Although much research has been conducted to reduce the thickness of PET bottles in order to save manufacturing costs, the challenge remains of guaranteeing mechanical strength for top-loaded thin PET bottles. The current study investigates the large deformation characteristics of a circle shaped PET bottle and a square shaped PET bottle when compressively loaded using FEA. The arc length method is used in the nonlinear FEA to understand the buckling phenomenon. For PET bottles with the same capacity, the circle shaped bottle shows more resistance to buckling and compression loading than the square shaped bottle.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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• pp.92-95
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• 2002

A nonlinear finite element method is presented to evaluate the torsional buckling moment and failure of composite laminated cylinders. For the progressive failure analysis, the complete unloading method is used based on the maximum stress failure criteria. An arc-length method is incorporated to trace the postbuckling equilibrium path. Present finite element method is verified by the existing experimental and analytical results. The results of the parametric study show that the torsional buckling moments are sensitive to the geometric change, but are not much affected by the lay-up angle. All cylinders tested numerically show the unstable torsional buckling, and therefore the torsional buckling always leads to the catastrophic failure.

• 대한기계학회논문집A
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• 제20권11호
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• pp.3441-3453
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• 1996

A finite element anlaysis is performed for large deformations of a felxible beam. The total Lagrangian formulation for a general large deformation, which involves finite rotations, is chosen and the exponential map is used to treat finite rotations from the Eulerian point of view. The finite elements results are confirmed for several cases of deformations through comparison to a first order elasticity solution obtained by numerical integration, and the agreement between the two is found to be excellent. For lateral buckling, the point of vanishing determinant of the resulting unsymmetric tangent stiffness is traced to examine its relationship to bifurcation points. It is found that the points of vanishing determinant is not corresponding to bifurcation points for large deformation in general, which suggests that the present unsymmetric tangent stiffness is not an exact first derivative of internal forces with respect to displacement.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.446-449
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• 1997

Yard cranes are very useful equipments for handling of heavy containers. But rope-driven yard cranes must have a little of sway and skew motion because ropes arc passive mechanical device. So many researches have been concentrated on anti-sway algorithm controlling trolley speed. But control algorithm of trolley speed is not practical in windy weather. In this paper, we are going to propose a new structure for anti-sway. This structure uses aux. :opes. The control strategy with auxiliary rope is very useful to sway control of yard crane because rope length is shorter than quay-sidc container cranes. In this paper, we derive cquatlons of motion of trolley system which have anti-sway controller to use auxiliary rope. And we propose the control strategy and analyse the behavior of the proposed system.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.496-503
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• 2003

Recently, the buckling is easy to happen a thin plate and High Tensile Steel is used at the structure so that it is wide. Especially, the buckling is becoming important design criteria in the ship structure to use especially the High Tensile Steel. Consequently, it is important that we grasp the conduct after the buckling behaviour accurately at the stability of the body of ship structure. In this study, examined closely about conduct and secondary buckling after initial buckling of thin plate structure which receive compressive load according to various kinds aspect ratio under simply supported condition that make by buckling formula in each payment in advance rule to place which is representative construction of hull. Analysis method is F.E.M by ANSYS and complicated nonlinear behaviour to analyze such as secondary buckling.

• 한국해양공학회지
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• 제11권4호
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• pp.7-22
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• 1997

A finite element analysis is performed for lateral buckling problems on the basis of a geometrically nonlinear formulation for a beam with small elastic strain but with possibly large rotations. The total Lagrangian formulation for a general large deformation, which involves finite rotations, is chosen and the exponential map is used to treat finite rotations from the Eulerian point of view. For lateral buckling, the point of vanishing determinant of the resulting unsymmetric tangent stiffness is traced to examine its relationship to bifurcation points. It is found that the points of vanishing determinant is not corresponding to bifurcation points for large deformations in general, which suggests that the present unsymmetric tangent stiffness is not an exact first derivative of internal forces with respect to displacement. This is illustrated through several numerical examples and followed by appropriate discussion.

• 한국데이터정보과학회:학술대회논문집
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• 한국데이터정보과학회 2006년도 PROCEEDINGS OF JOINT CONFERENCEOF KDISS AND KDAS
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• pp.43-47
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• 2006

Consider a multitype queue where queued customers arc served in their order of arrival at a rate which depends on the customer type. Here we calculate the sharp asymptotics of the probability the total number of customers in the queue reaches a high level before emptying. The natural state space to describe this queue is a tree whose branches increase in length as the number of customers in the queue grows. Consequently it is difficult to prove a large deviation principle. Moreover, since service rates depend on the customer type the stationary distribution is not of product form so there is no simple expression for the stationary distribution. Instead, we use a change of measure technique which increases the arrival rate of customers and decreases the departure rate thus making large deviations common.

• Architectural research
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• 제20권1호
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• pp.9-16
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• 2018

Nonlinear analysis of reinforced concrete (RC) structures is performed by using isogeometric Reissner-Mindlin (RM) shell element. The elasto-plastic constitutive model is employed to express the nonlinear behavior of concrete material and the equivalent smeared steel layer is introduced to represent steel reinforcement. The arc-length control method is used to produce the entire load-displacement path of RC structures. Finally, three benchmark tests are carried out to verify the performance of the present shell element. From isogeometric analysis, the present results show a good agreement with experimental results and it is provided as future benchmark test solutions.

• 한국전산유체공학회지
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• 제5권1호
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• pp.14-21
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• 2000

A method of two and three dimensional orthogonal grid generation with control of spacing by using the covariant Laplace equation is presented. An important feature of the methodology is its ability to control effectively the grid spacing especially near the boundaries still maintaining good orthogonality in whole field. The method is based on the concept of decomposition of the global transformation into consecutive transformation of an approximate conformal mapping and an auxiliary orthogonal mapping to have linear and uncoupled equations. Control of cell spacing is based on the concept of reference arc length, and orthogonal correction is peformed in the auxiliary domain. It is concluded that the methodology can successfully generate well controlled orthogonal grids around bodies of 2 and 3 dimensional configurations.

• 한국공간구조학회:학술대회논문집
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• 한국공간구조학회 2005년도 춘계학술발표회 및 정기총회 2권1호(통권2호)
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• pp.89-98
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• 2005

Membrane structures, a kind of lightweight soft structural system, are used for spatial structures. The material property of the membrane has strong axial stiffness, but little bending stiffness. Therefore membrane structures arc unstable structures initially. These soft structures need to be introduced initial stresses first because of its initial unstable state, and it happens large deformation phenomenon. To find the structural shape after large deformation caused by initial stiffness introduced, we need the shape analysis considering geometric nonlinearity in structural design procedure. In this study, we investigate into the stress concentration at crack of membrane structures. Therefore, using the nonlinear analysis program that NASS (Nonlinear Analysis for Spatial Structures) perform nonlinear analysis, and stress distribution for creak length investigate for using linear elastic fracture mechanics.