• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.90-100
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• 2000

The present paper investigates the elasto-plastic buckling of ball-jointed single layer latticed domes considering the connection characteristics. The domes are composed of tubular member elements, ball joints and connectors. To judge yielding of the member, the ends and central part of tubular member elements are assumed as five elasto-plastic springs. Elasto-plastic buckling load can be identified the yielding load of estimated member As a numerical analysis technique, loading incremental method based on the Newton-Raphson method is used. The effects of connection characteristics are investigated by the following points; (1) the length of rigid zone, (2) looseness of screw, (3) diameter of connector Finally, it is emphasized that the connection characteristics as well as the material non-linearity have significant effects upon the buckling toad of domes.

• Bulletin of the Society of Naval Architects of Korea
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• v.17 no.1
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• pp.1-10
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• 1980

The nonlinear analysis of ship plating with flat bar stiffners has been carried out by the finite element method based on the load incremental approach. The large deflection analysis has been done by using the Lagrangian description. The elastoplastic analysis has been performed by adopting the flow theory of plasticity and the von Mises yield condition. The layered elements are used to show the process of yielding through the plate thickness in the elasto-plastic analysis. The following results are obtained; 1) According to the large deflection analysis, it is shown that the small deflection theory to the plate is applicable in the range of the lateral deflection-the thickness ratio $w/h{\leqq}0.3$ and ship plating in the range of $w/h{\leqq}0.5$. 2) By means of the elasto-plastic analysis, it is found that the maximum load-carrying capacity of the plate increases as much as 1.8 times of the initial yield load in the case of the simply supported condition and 2.2 times in the clamped condition. It is also shown that the maximum load-carrying capacity of ship plating increase as much as 4.3 times in the simply supported condition and 4.2 times in the clamped condition. This method would be applied and extended to solve combined nonlinear problems which involve both material nonlinearity and geometric nonlinearity.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.11a
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• pp.429-434
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• 2000

본 연구에서는 등분포하중을 받는 laminated 박판의 거동해석을 제시하였다. 접착한 두 박판의 비선형 지배방정식을 Von Karman 식을 이용하여 유도하고 박판의 거동을 차분법을 이용하여 수치해석 한다. Interlayer에서의 전단변형을 고려하여 지배방정식에 포함시켜 하중 증분법(load incremental method)으로 기하학 비선형 해석을 수행한다. 하중 증분법에 따른 반복법을 도입하여 비선형 방정식을 해석했다. 해석방법의 타당성을 입증하기 위하여 해석결과들을 기존의 문헌의 결과와 비교, 검토함으로써 본 논문에서 제시한 이론 및 해석방법의 타당성을 입증한다. 차분법의 하중 증분법 알고리즘을 개발하여 예제문제에 대한 수치해석 결과들을 논하였다.(중략)

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.10a
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• pp.28-31
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• 1997

Buckling analysis of thin compressed beam has been carried out. Pre-buckling and post-buckling are simulated by finite element method incorporating with the incremental nonlinear theory and the Newton-Raphson solution technique. In order to find the bifurcation point, the determinent of the stiffness matrix is calculated at every iteration procedure. For post-buckling analysis, a small perturbed initial guess is given along the eigenvector direction at the bifurcation point. Nonlinear elastic buckling and elastic-plastic buckling of cantilever beam are analyzed. The buckling load and buckled shape of the two models are compared.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.4
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• pp.1-10
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• 1992

Since the structural system of a prestressed concrete bridge erected by Incremental Launching Method is varying continuosly during construction, the main girder bears alternating stress resultants different from those under a service load condition. The magnitude of these stress resultants depends on span lengths, nose length and stiffness ratios between girder and nose. A parametric study is performed for various span lengths, nose lengths and stiffness ratios. In order to analyze structural systems varying at every launching step two programs are developed; a pre-processor which automatically produces a data file for each stage and a main-processor which can summarize the results of all stages. From the results, the relationships between optimum nose length and stiffness ratio are proposed for various span lengths.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.2
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• pp.21-28
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• 1987

The paper describes the analysis of large displacement problems including instability phenomena. The element used in this is a degenerated isoparametric shell element with eight nodes. Total Lagrangian formulation has been adopted in this study using Newton-Raphson iteration method with incremental load. The linear stability analyses performed usually for the initial position can be repeated at several advanced fundamental states on the non-linear buckling path. Thus a current estimate of the failure load is given. The numerical examples of a cylindrical panel under uniform load, simply supported plate under axial load, and clamped plate under uniform load are carried out. The examples applying degenerated isoparametric elements to bifurcation buckling and nonlinear collapse problems are also performed.

• Proceedings of the KAIS Fall Conference
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• 2002.11a
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• pp.141-144
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• 2002

Recently, the operation of power distribution systems has become more difficult because the peak demand load is increasing continuously and the daily load factor is getting worse and worse. Also, the consideration of deregulation and global environment in electric power industry is required. In order to overcome these problems, a study on the planning and operation in distribution systems of dispersed generating sources such as fuel cell systems, photovoltaic systems and wind power systems has been performed energetically. This study presents a method for determining an optimal operation strategy of dispersed co-generating sources, especially fuel cell systems, in the case of both only electric power supply and thermal supply as well as electric power supply. In other words, the optimal operation of these sources can be determined easily by the principle of equal incremental fuel cost and the thermal merits is evaluated quantitatively through Kuhn-Tucker's optimal conditions. In order to select the optimal locations of those sources, an priority method using the comparison of total cost at the peak load time interval is also presented. The validity of the proposed algorithms is demonstrated using a model system.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.6
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• pp.265-274
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• 2001

Recently, the operation of power systems has become more difficult because the peak demand load is increasing continuously and the daily load factor is getting worse and worse. Also, the consideration of deregulation and global environment in electric power industry is required. In order to overcome those problems, a study on the planning and operation in power systems of dispersed generating sources such as fuel cell systems, photovoltaic systems and wind power systems, has been performed energetically. This paper presents a method for determining an optimal operation strategy of dispersed co-generating sources, especially fuel cell generation systems, considering thermal supply as well as electric power supply. In other words, the optimal operation of those sources can be determined easily by the principle of equal incremental fuel cost and the thermal merit of those sources can be also evaluated quantitatively through Kuhn-Tucker's optimal conditions. In additions, an priority method using the comparison of total cost at the peak load time interval is presented in order ot select the optimal locations of those sources. The validity of the proposed algorithms is demonstrated using a model system.

• The Journal of the Korea Contents Association
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• v.16 no.2
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• pp.163-173
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• 2016

Recently, massive amounts of stream data have been studied for distributed processing. In this paper, we propose an incremental stream data processing method based on in-memory in big data environments. The proposed method stores input data in a temporary queue and compare them with data in a master node. If the data is in the master node, the proposed method reuses the previous processing results located in the node chosen by the master node. If there are no previous results of data in the node, the proposed method processes the data and stores the result in a separate node. We also propose a job scheduling technique considering the load and performance of a node. In order to show the superiority of the proposed method, we compare it with the existing method in terms of query processing time. Our experimental results show that our method outperforms the existing method in terms of query processing time.

• Transactions of Materials Processing
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• v.11 no.1
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• pp.84-89
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• 2002

This study is concerned with the analysis of the forming characteristics of radial-forward extrusion. Angle between radial and forward extrusion, gap height, and friction factor are considered as important design factors to affect forming characteristics in radial-forward extrusion. The rigid-plastic finite element method is adopted to analyze the effects of design factors on forming loads. The incremental rates of loads are nearly constant except the deformation zone from radial to forward extrusion. The smaller angle induces lesser force increment, therefore forming load increases as the angle increases. Maximum load also increases as gap-height decreases and friction factor increases.