• Architectural research
• /
• 제9권1호
• /
• pp.39-45
• /
• 2007

The static behavior of continuous system is described by the elastic curve method or is approximately analyzed by a finite element method to be modeled as a discrete system. If a continuous system is constrained by linear constraints which restrict its static behavior, its behavior can be approximately described by the finite element method. It is not easy to describe the constrained behavior by continuous coordinate system. Starting from the generalized inverse method provided by Eun, Lee and Chung, this study is to expand the equation to the continuous systems, to perform the structural analysis of the beam under a uniform loading with interior spring supports, and to investigate the validity of the proposed method through applications.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2001년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2001
• /
• pp.147-154
• /
• 2001

In this study, comprehensive seismic performance analysis were performed for the concrete face rockfill dam(CFRD) designed seismic coefficient method(0. 10g). The static and pseudo-static FEM analysis, limited equilibrium method and dynamic FEM analysis were used for the dam safety analysis. The results of the seismic analysis were that the minimum factor of safety of down slope was 1.2 and horizontal displacement increased 8cm and vertical displacement increased 1.2cm at dam crest rather than those of static condition. The model dam did not show any serious tai lure in seismic stabi1ity for 0.13g. And much more research is still necessary in seismic safety of CFRD.

• Structural Engineering and Mechanics
• /
• 제4권5호
• /
• pp.529-540
• /
• 1996

The dynamic buckling mechanism of a single-degree-of-freedom dissipative/nondissipative gradient system is thoroughly studied, employing energy criteria. The model is chosen in such a manner, that its corresponding static response is associated with all types of distinct critical points. Under a suddenly applied load of infinite duration, it is found that dynamic buckling, occurring always through a saddle, leads to an escaped motion, which is finally attracted by remote stable equilibrium positions, belonging sometimes also to complementary paths. Moreover, although the existence of initial imperfection changes the static behaviour of the system from limit point instability to bifurcation, it is established that the proposed model is dynamically stable in the large, regardless of the values of all other parameters involved.

• 대한기계학회논문집A
• /
• 제28권2호
• /
• pp.133-142
• /
• 2004

In this article, the constitutive relations of three types of piezoelectric benders, which are a unimorph bender, a bimorph bender and a triple-layer bender, are derived based on the beam theory under the quasi-static equilibrium condition. The relation coefficients are described as the geometry and material properties of the benders. More general constitutive relations involving fixed-free, fixed-roll, and fixed-simply supported boundary conditions under the inconsistent length condition between the piezoelectric layer and the nonpiezoelectric one are discussed. The complicated constitutive relations can be easily calculated and checked by using the symbolic function in ‘Mathematica’. The relation coefficients for the benders are plotted in three dimensional graph using the developed program.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2005년도 추계학술대회 논문집
• /
• pp.1165-1170
• /
• 2005

In order to perform the spatial buckling analysis of the curved beam element with nonsymmetric thin-walled cross section, exact static stiffness matrices are evaluated using equilibrium equations and force-deformation relations. Contrary to evaluation procedures of dynamic stiffness matrices, 14 displacement parameters are introduced when transforming the four order simultaneous differential equations to the first order differential equations and 2 displacement parameters among these displacements are integrated in advance. Thus non-homogeneous simultaneous differential equations are obtained with respect to the remaining 8 displacement parameters. For general solution of these equations, the method of undetermined parameters is applied and a generalized linear eigenvalue problem and a system of linear algebraic equations with complex matrices are solved with respect to 12 displacement parameters. Resultantly displacement functions are exactly derived and exact static stiffness matrices are determined using member force-displacement relations. The buckling loads are evaluated and compared with analytic solutions or results by ABAQUS's shell element.

• Structural Engineering and Mechanics
• /
• 제19권4호
• /
• pp.459-475
• /
• 2005

This paper deals with a novel application of the Generalized Differential Quadrature (G.D.Q.) method to the linear elastic static analysis of isotropic rotational shells. The governing equations of equilibrium, in terms of stress resultants and couples, are those from Reissner-Mindlin shear deformation shell theory. These equations, written in terms of internal-resultants circular harmonic amplitudes, are first put into generalized displacements form, by use of the strain-displacements relationships and the constitutive equations. The resulting systems are solved by means of the G.D.Q. technique with favourable precision, leading to accurate stress patterns.

• Tribology and Lubricants
• /
• 제24권6호
• /
• pp.378-385
• /
• 2008

In foil bearings, the friction between bumps and their mating surfaces is the major factor which exerts great influence on the bearing performance. From this point of view, many efforts have been made to improve the understanding of the influence of the friction on the foil bearing performance by developing a number of analytical models. However, most of them did not consider the hysteretic behavior of the foil structure resulting from the friction. The present work developed the static structural model in which hysteretic behavior of the friction was considered. The foil structure was modeled using finite element method and the algorithm which determines the conditions of the contact nodes and the directions of the friction forces was used to take into account the friction. The developed model was integrated into the foil bearing prediction code to investigate the effects of the friction on the static performance of the bearing. The results of analysis show that multiple static equilibrium positions are presented for the one static load under the influence of the friction, inferring its great effects on the dynamic performance. However, the effect of friction on the minimum film thickness which determines load capacity of the bearing is negligible.

• 자원ㆍ환경경제연구
• /
• 제18권1호
• /
• pp.23-51
• /
• 2009

본 연구는 우리나라가 자유무역정책을 실시할 경우 경제 전반과 친환경연료인 바이오디젤 산업에 미치는 영향을 정태적 연산가능일반균형모형(CGE)을 이용하여 분석하였다. 이론적으로 자유무역과 환경 간의 관계에 대해서는 '공해안식처 가설'이 1970~1980년대를 풍미하였으나, 1990년대 이후 Townsend and Ratnayakee 등은 자유무역이 생산효과, 규모효과, 구조효과, 규제효과를 통해 친환경기술 도입을 촉진하는 기능이 있음을 역설한 바 있다. 본 연구는 이러한 측면에서 과연 무역자유화의 효과로서 관세철폐가 우리나라 바이오디젤 산업에 어떤 영향을 미칠 수 있는지를 정량적으로 분석했다는 점에서 의의가 있다. 연구 결과 관세가 철폐되면 농업부문 산출은 전반적으로 감소하는 반면, 바이오디젤 산업은 팽창하며, GDP와 소비자 후생이 증가하는 것으로 나타났다. 바이오디젤 산업이 팽창하는 것은 원료인 대두유가 해외에서 수입됨에 따라 관세를 철폐할 경우 원료 수입가격이 하락하기 때문이다. 즉, 토지 생산성 측면에서 우리나라에서 생산되는 원료를 바이오디젤 원료로 이용하기보다는 동남아나 북 중남미 등에서 원료를 개척하여 수입하는 것이 경제적 이익을 극대화할 수 있고, 자유무역은 이를 더욱 가속화시킬 수 있다는 것이다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제13권10호
• /
• pp.5260-5275
• /
• 2019

In the process of constructing the traditional offensive and defensive game theory model, these are some shortages for considering the dynamic change of security risk problem. By analysing the critical indicators of the incomplete information game theory model, incomplete information attack and defense game theory model and the mathematical engineering method for solving Bayes-Nash equilibrium, the risk-averse income function for information assets is summarized as the problem of maximising the return of the equilibrium point. To obtain the functional relationship between the optimal strategy combination of the offense and defense and the information asset security probability and risk probability. At the same time, the offensive and defensive examples are used to visually analyse and demonstrate the incomplete information game and the Harsanyi conversion method. First, the incomplete information game and the Harsanyi conversion problem is discussed through the attack and defense examples and using the game tree. Then the strategy expression of incomplete information static game and the engineering mathematics method of Bayes-Nash equilibrium are given. After that, it focuses on the offensive and defensive game problem of unsafe information network based on risk aversion. The problem of attack and defense is obtained by the issue of maximizing utility, and then the Bayes-Nash equilibrium of offense and defense game is carried out around the security risk of assets. Finally, the application model in network security penetration and defense is analyzed by designing a simulation example of attack and defense penetration. The analysis results show that the constructed income function model is feasible and practical.

• 로봇학회논문지
• /
• 제15권4호
• /
• pp.301-308
• /
• 2020

In this paper, we deal with the static modeling of a continuum robot that can perform surgical interventions. The proposed continuum robot is made of stainless steel wires and a multi lumen flexible tube using a thermoplastic elastomer. This continuum robot could be most severely deformed in physical contact with narrow external environments, when a lateral external force acts at the distal tip of the continuum robot. In order to predict the shape and displacement under the lateral external force loading, the forward kinematics, the statics modeling, the force-moment equilibrium equation, and the virtual work-energy method of the continuum robot are described. The deflection displacements were calculated using the virtual work-energy method, and the results were compared with the displacement obtained by the conventional cantilever beam theories. In conclusion, the proposed static modeling and the virtual work-energy method can be used in arrhythmia procedure simulations.