• Journal of Korean Society of Steel Construction
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• v.20 no.3
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• pp.421-435
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• 2008

This paper presents an investigation on the ultimate behavior of a transmission tower using nonlinear analyses inconsideration of residual stress and initial imperfection. Main members, such as main post, horizontal member and diagonal member of the transmission tower were modeled using beam element. Moreover, submembers of the transmission tower were modeled using truss element. ABAQUS (2004) program was used to perform finite element analyses. Initial condition options of the ABAQUS program considering initial stress and imperfection were used in this study. Before performing the analysis of the total transmission tower, simple angle section models using beam or plate/shell element w ere investigated to verify the appropriateness of ABAQUS analysis models and options. According to the verification results, the beam element was used for nonlinear analyses of the transmission tower. From nonlinear analyses results, buckling failure was in the main member of the leg part because of ${P-{\triangle}}$ effect at that point. Also, this paper includes significant results to define real structural failure modes and quantitative values. This study should be used in the development of a reasonable and economic design method for transmission towers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2A
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• pp.85-95
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• 2012

This paper presents an investigation on the ultimate behavior of steel cable-stayed bridges using nonlinear finite element analysis method. Cable-stayed bridges exhibit various geometric nonlinearities as well as material nonlinearities, so rational nonlinear finite element analysis should be performed for investigation of the ultimate behavior. In this study, ultimate behavior of steel cable-stayed bridges was studied using rational ultimate analysis method. Nonlinear equivalent truss element and nonlinear frame element were used for modeling the cable, girder and mast. Moreover, refined plastic hinge method was adopted for considering the material nonlinearity of steel members. In this study, the 2-step analysis method was used. Before live load analysis, initial shape analysis was performed in order to consider the dead load condition. For investigation of the ultimate behavior of steel cable-stayed bridges, analysis models which span length is 920.0 m were used. Radiating type and fan type were considered as the cable-arrangement types. With various quantitative evidences such as load-displacement curves, deformed shapes, locations of the yield point or region, bending moment distribution and so on, the ultimate behavior of steel cable-stayed bridges was investigated and described in this paper.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1A
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• pp.1-13
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• 2010

This paper presents an investigation on the geometric nonlinear behavior of cable-stayed bridges using geometric nonlinear finite element analysis method. The girder and mast in cable-stayed bridges show the combined axial load and bending moment interaction due to horizontal and vertical forces of inclined cable. So these members are considered as beam-column member. In this study, the nonlinear finite element analysis method is used to resolve the geometric nonlinear behavior of cable-stayed bridges in consideration of beam-column effect, large displacement effect (known as P-${\delta}$ effect) and cable sag effect. To analyze a cable-stayed bridge model, nonlinear 6-degree of freedom frame element and nonlinear 3-degree of freedom equivalent truss element is used. To resolve the geometric nonlinear behavior for various live load cases, the initial shape analysis is performed for considering dead load before live load analysis. Then the geometric nonlinear analysis for each live load case is performed. The deformed shapes of each model, load-displacement curves of each point and load-tensile force curves for each cable are presented for quantitative study of geometric nonlinear behavior of cable-stayed bridges.

• Structural Engineering and Mechanics
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• v.7 no.4
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• pp.413-432
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• 1999

A macro-element model is developed to account for shear deformation and bond slip of reinforcement bars in the beam-column joint region of reinforced concrete structures. The joint region is idealized by two springs in series, one representing shear deformation and the other representing bond slip. The softened truss model theory is adopted to establish the shear force-shear deformation relationship and to determine the shear capacity of the joint. A detailed model for the bond slip of the reinforcing bars at the beam-column interface is presented. The proposed macro-element model of the joint is validated using available experimental data on beam-column connections representing exterior joints in ductile and nonductile frames.

• KCI Concrete Journal
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• v.13 no.2
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• pp.67-74
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• 2001

In this study, a numerical model for the simulation of reinforced concrete columns subject to cyclic loading is presented. The model consists of three separate models representing concrete, reinforcing steel bars and bond-slip between a reinforcing bar and ambient concrete. The concrete model is represented by the plane stress plastic-damage model and quadrilateral finite elements. The nonlinear steel bar model embedded in truss elements is used for longitudinal and transverse reinforcing bars. Bond-slip mechanism between a reinforcing bar and ambient concrete is discretized using connection elements in which the hysteretic bond-slip link model defines the bond stress and slip displacement relation. The three models are connected in finite element mesh to represent a reinforced concrete structure. From the numerical simulation, it is shown that the proposed model effectively and realistically represents the overall cyclic behavior of a reinforced concrete column. The present plastic-damage concrete model is observed to work appropriately with the steel bar and bond-slip link models in representing the complicated localization behavior.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.449-454
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• 2002

For finite analysis of concrete columns strengthened with glass fiber sheets, an effective concrete model which considers the confining effects by lateral reinforcement and glass fiber sheets is necessary. In this paper, the so-called elasto-plasticity and continuum fracture model (EPF model) is modified to consider high confining effects of strengthened reinforced concrete columns by introducing a simple correction factor ($\alpha$) which relates maximum lateral confining stress of the column to the evolution of deviatoric plasticity. Then, a finite element analysis is carried out for the strengthened reinforced concrete columns using the modified EPF model and equally spaced truss elements. It is shown that the, analysis predicts well the failure behavior of reinforced concrete columns strengthened with glass fiber sheets.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.665-670
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• 1999

The shear behavior and strength of simply supported reinforced concrete deep beams with web opening subject to concentrated loads have been investigated experimentally on the effects of structural parameters such as location of web opening and reinforcements. A total of 12 specimens were tested at the laboratory under two-point top loading. The shear span-to-depth ratio was taken constantly 0.8, and various types of reinforcements based on truss models were adopted. In the tests, the effects of location, reinforcements of web openings on the shear behavior, and crack initiation and propagation have been carefully checked and analyzed. The test results have been compared with the formulas proposed currently being used and analyzed by nonlinear finite element method. Shear strengths obtained from the tests showed good matches with Kong and Ray's equation, and also with the results calculated by nonlinear finite element method.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.3
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• pp.82-89
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• 2002

The need of ultra-precision machine tools, which manufacture and machine the high precision parts used in computers, semi-conductors and other precision machines, has been increased over years. Therefore it is important to design the driving parts, which affect significantly on their performances. In this paper, the dynamic analyses on the belt-driven system were explored. Relation of the acoustical natural frequency and the tension of belt was derived and presented through experiments. Also, while the dynamic loads on motor system were changed, dynamic deflections were calculated through finite element analysis. Nonlinear characteristics of the bearings having an effect on the dynamic performance were studied and the belt connecting the motor (driving part) to spindle of a machine tool (driven part) was modeled as truss and beam elements fur simulations under various conditions, and a beam element model was verified to be more useful.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.4
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• pp.66-76
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• 1999

In this study , the optimum structural components for the rural house design using the light gauge cold-formed steel frame is proposed. The proposed components were optimzed by the developed model composed with the analysis model and LGC database. The analysis model adapts FEA(finite element analysis). LGC database and calculation of element force adapt the design criteria of KISC. The structure of house is divided into header, bearing wall and foof truss. The variable of the each structure of house are defined component which designed by the case of load, aize and space. The designed weight were used for optimization procedure of the divided components.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.04a
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• pp.61-70
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• 1997

This paper presents several modeling methods to analyze the stub-girder system, testifies those methods base on actual test results for the behavior of the simply supported stub-girder system, and finally, by changing the boundary conditions in those models, predicts the behavior of the fixed end stub-girder system. Two different methods are used for the structural modeling. In the first method, the stub-girder is modeled as a vierendeel truss girder, and in the second method, as a finite element model. Both methods use the finite element analysis software package LUSAS™ for linearly elastic analyses and nonlinear analyses.