• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.215-222
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• 1996

원전 격납구조물의 구조해석에 대한 대부분의 연구에서 격납구조물을 축대칭으로 모델하고 있다. 따라서 격납구조물에 배근된 강재도 축대칭으로 가정하는 것이 일반 적이며, 유한요소모델 구성시 강재는 2절점 트러스나 1절점 링 트러스요소에 의해서 모델한다. 이때 유효철근비는 트러스요소의 단면적에 의해서 표현되며, 원통형 벽체에서는 높이에 따라 배근된 강재량이 일정하므로 실제와 근접한 모델이 가능하다. 그러나, 상부돔의 축대칭모델시 돔의 자오선 방향으로 규정된 강재량이 일정치 않고, 변화하게 된다. 기존에 연구에서는 이러한 강재량의 변화를 고려하지 못하고 반경방향으로 일정한 것으로 가정하여 구조해석을 수행하여 왔다. 이와같은 모델상의 제약으로 인해서 철근이나 텐던의 조기항복, 돔 정상부 부근에서의 부 정확한 변형특성을 보이고 있다. 본 연구에서는 실제 규정된 강재량을 유한요소모델에 반영하기 위해 정점부에서 자오선 방향으로 변화되는 강재량을 모델할 수 있는 기법에 대해서 연구하였으며, 연구결과를 바탕으로 격납구조물의 극한 내압해석을 수행하여 기존 모델방법에 의한 해석결과와 비교하였다.

• Journal of Korean Society of Steel Construction
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• v.20 no.3
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• pp.377-387
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• 2008

The post-buckling behavior of slender members, such as the chord of truss structures generally implies extreme strength degradation. The buckling strength is usually determined as the performance of the compressed steel members, so it is important to understand the exact buckling behavior of a member in order to design the entire structure. A target analytical model is usually divided by beam or shell element when we simulate the buckling behavior of a compressed steel member such as atruss member. In this case, it is possible to accurately obtain the behavior, but such would be expensive and would require experience inanalysis even in monotonic loading. In this paper, we propose a consistent and convenient method to analyze the post-buckling behavior of elastoplastic compression members. The present methods are formulated to satisfy the second law of thermodynamics. Three numerical examples were tested to determine the validity of the proposed model in cyclic loading with comparable F.E.M results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.3
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• pp.92-98
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• 2012

This study shows details of a specific space truss frame structure devised to carry out maintenance and repair temporary works in tunnels. The purpose of this study is to verify structural safety and function of the innovative truss structure through an analysis tool, i.e.. ABAQUS, which is a suite of software application for finite element analysis and computer aided engineering. And then optimized size, i.e., thickness and diameter of truss members is evaluated in practice. In this study, construction methods in the temporary works are additionally represented by using the new space truss frame structure.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.1
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• pp.55-63
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• 1993

Finite element analyses are conducted with stochastic elastic moduli when truss structures are subjected to static loads of a deterministic nature. Stochastic stiffness matrix is derived from stochastic shape functions and numerical analyses are performed within the framework of the Monte Carlo method. Analysis methods are verified for the space truss and applied to cable stayed bridge for determining the cable force.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.3
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• pp.319-328
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• 2011

This paper introduces the construction of Strut-Tie model based on the Evolutionary Structural Optimization(ESO) method. Differently from conventional ESO method which uses plane stress elements, the introduced approach adopts the use of truss elements with the fact that the optimum topology of structures by ESO method is open a truss-like structure. Several examples are provided to demonstrate the capability of the proposed method in finding the best Strut-Tie models. In advance, it is shown that the introduced method is supported through the correlation studies between two-dimensional plane stress analysis and Strut-Tie models, and can be used effectively in practice, especially in shear design of complex reinforced concrete members where no previous experience is available.

• Journal of the Korean Society of Hazard Mitigation
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• v.1 no.2 s.2
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• pp.63-74
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• 2001

In this paper the feasibility of Nondestructive Damage Detection (NDD) in large structures is demonstrated via simulating vibration monitoring of such structures. The theory of NDD for truss type structures is formulated. To examine the feasibility of the theory, a finite element model of a 3-D truss structure, which consists of sixteen bays and includes 246 elements, is developed to simulate damage. Four damage cases are simulated numerically and the cases range from the structure being damaged in one location to the structure being damaged in three locations. For the given modal parameters, this study reveals very good results for small amounts of damage as well as large damage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.697-702
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• 2017

A preliminary study was carried out to investigate the feasibility of replacing honeycomb cores with pyramidal truss cores in the doors of urban transit railway vehicles. The doors in current operation are sandwich structures comprising a honeycomb core and reinforcements between two facesheets. The structural requirements of doors for urban transit vehicle are specified in the KRS and KRT and standards, according to which the deflections from three-point bending tests must be limited. To this end, two types of pyramidal truss cores with equivalent mass to a honeycomb core were designed. The structural stiffness of doors with pyramidal truss cores and honeycomb cores were numerically calculated via finite element analysis. The three-point bending models were constructed and simulated, and then the calculated deflections were compared with the requirements specified in the regulations. The results show that doors with pyramidal truss cores satisfied the stiffness requirements, although their deflections were 2.5% larger than that of the honeycomb cores. Therefore, the pyramidal truss cores could replace the aluminum honeycomb cores, and their multi-functional capability could be exploited.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.1
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• pp.175-181
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• 2010

The three truss models(equilibrium truss model, Mohr compatibility truss model, and the soften truss model) based on a rotating angle is called the rotating-angle model. The three rotating-angle models have a common weakness: they are incapable of predicting the so-called "contribution of concrete". To take into account this "contribution of concrete", the modern truss model(MCFT, STM) treats a cracked reinforced concrete element as a continuous material. By combining the equilibrium, compatibility, and the softened stress-strain relationship of concrete in biaxial state, MTM is capable of producing the nonlinear analysis of reinforced concrete structures composed of membrane element. In this paper, an efficient algorithm is proposed for the solution of proposed model incorporated with failure criteria. This algorithm is used to analyze the behavior of reinforced membrane element using the results of Hsu test.

• Magazine of the Korea Concrete Institute
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• v.3 no.3
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• pp.149-157
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• 1991

This paper concentrates on the nonlinear analysis of the reinforced concrete flexural members under cyclic loading. To develop a nonlinear material model, concrete is treated as an orthotropic nonlinear material and steel is modeled as an elasto-plastic material. The models for hysteresis behavior with stiffness degradation in compression and for crack opening and closing in tension are included. The finite element computer program for the nonlinear analysis of RC flexural members under cyclic loading is developed. The accuracy and reliabihty of the numerical procedure IS demonstrated by the FEM analysis and test results of underreinforced concrete beams.

• Journal of the Korea Concrete Institute
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• v.20 no.6
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• pp.705-712
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• 2008

This study carried out simulation for structural layout design for concrete structures by using the models of the ground structure method. The micro lattice truss is modeled as assemblage of a number of unit cells. The progress of analysis repeat to undergo finite element analysis to feed-back results of stress to the stiffness of each member. Through the repeated this analysis, truss model is represented to form the topological materials and the structural shape with the use of the local stress condition without mathematical optimum tools. It is successful to analyse the shape-layout problem as numerical samples on the lattice truss model.