• Structural Engineering and Mechanics
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• v.21 no.4
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• pp.451-468
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• 2005

Effective beam width models are commonly used to obtain the lateral stiffness of flat plate structures. In these models, an effective beam width is defined as the width when the flexural stiffness of the beam element equals the slab stiffness. In this present study, a method to obtain effective beam widths that considers the effects of connection geometry and slab cracking is analytically proposed. The rectangularity of the vertical member for the connection geometry and the combined effects of creep and shrinkage for the slab cracking are considered. The results from the proposed method are compared with experimental results from a test structure having nine slab-column connections.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.680-683
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• 2010

The lateral stiffness of the track structure is very important mechanical property to prevent the track buckling and progress of misalignment. The increasing methods of the lateral stiffness of the track structure are the following; increases of the lateral ballast resistance, and increases of the lateral stiffness of the track panel. In order to increase the lateral stiffness of the tack panel, some of the sleepers resist together against the lateral movement can be the most economical and mechanical method. In this paper, H-typed sleeper developed to solve this problem is introduced and the mechanical advantages of this sleeper are investigated.

• Journal of Power System Engineering
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• v.5 no.4
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• pp.24-30
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• 2001

The substructure synthesis method(SSM) is developed for overcoming disadvantages of the Finite Element Method(FEM). The concept of the SSM is as follows. After dividing a whole structure into several substructures, every substructures are analyzed by the FEM or experiment. The whole structure is analyzed by using connecting condition and the results of substructures. The concept of the transfer stiffness coefficient method(TSCM) is based on the transfer of the nodal stiffness coefficients which are related to force vectors and displacement vectors at each node of analytical mode1. The superiority of the TSCM to the FEM in the computation accuracy, cost and convenience was confirmed by the numerical computation results. In this paper, the author suggests an efficient vibration analysis method of structures by using the TSCM and the SSM. The trust and the validity of the present method is demonstrated through the numerical results for computation models.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.1 s.118
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• pp.80-87
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• 2007

In this paper, a method for identifying the location and extent of a damage in a structure using residual forces was presented. Element stiffness matrix reduction parameters in a finite element model were used to describe the damaged structure mathematically. The element stiffness matrix reduction parameters were determined by minimizing a global error derived from dynamic residual vectors, which were obtained by introducing a simulated experimental data into the eigenvalue problem. Genetic algorithm was used to get the solution set of element stiffness reduction parameters. The proposed scheme was verified using Euler-Bernoulli beam. The results were presented in the form of tables and charts.

• Journal of Power System Engineering
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• v.11 no.1
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• pp.92-97
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• 2007

It is important to compute the structural analysis of plate structures in structural design. In this paper, the author uses the finite element-transfer stiffness coefficient method (FE-TSCM) for the structural analysis of plate structures. The FE-TSCM is based on the concept of the successive transmission of the transfer stiffness coefficient method and the modeling technique of the finite element method (FEM). The algorithm for in-plane structural analysis of a rectangular plate structure is formulated by using the FE-TSCM. In order to confirm the validity of the FE-TSCM for structural analysis of plate structures, two numerical examples for the in-plane structural analysis of a plate with triangular elements and the bending structural analysis of a plate with rectangular elements are computed. The results of the FE-TSCM are compared with those of the FEM on a personal computer.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.161-168
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• 2003

In the drift design of high-rise buildings, once the geometry and dimensions of a structure are predetermined, engineer's remaining work is determination of the member size to satisfy the strength and the stiffness requirements. For the case of highrise buildings, designs are determined by the stiffness requirements at the final stage of structural design. Thus, engineers try to find a minimum weight design with maximum lateral stiffness. However, there is no guideline for engineers on the required weight of structures per unit area to satisfy the stiffness requirements. In this study, drift design method considering weight modification factors are presented and applied to a 20-story structure. The proposed drift design method considering weight modification factors may give the guideline for engineers on the amount of structural weight to attain target displacement.

• Structural Engineering and Mechanics
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• v.33 no.3
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• pp.325-337
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• 2009

Structural damage detection, damage localization and severity estimation of jacket platforms, based on calculating modal strain energy is presented in this paper. In the structure, damage often causes a loss of stiffness in some elements, so modal parameters; mode shapes and natural frequencies, in the damaged structure are different from the undamaged state. Geometrical location of damage is detected by computing modal strain energy change ratio (MSECR) for each structural element, which elements with higher MSECR are suspected to be damaged. For each suspected damaged element, by computing cross-modal strain energy (CMSE), damage severity as the stiffness reduction factor -that represented the ratios between the element stiffness changes to the undamaged element stiffness- is estimated. Numerical studies are demonstrated for a three dimensional, single bay, four stories frame of the existing jacket platform, based on the synthetic data that generated from finite element model. It is observed that this method can be used for damage detection of this kind of structures.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.190-195
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• 1997

Recently it is increased by degrees to construct complex or large lattice type structures such as bridges, towers, cranes, and structures that can be used for space technology. In general, in order to analyze, these structures we have used the finite element method(FEM). In this method, however, it is necessary to use a large amount of computer memory and computation time because the FEM requires many degrees of freedom for solving dynamic problems for these structures. For overcoming this problem, the authors have developed the transfer dynamic stiffness coefficient method(TDSCM). This method is based on the concepts of the transfer and the synthesis of the dynamic stiffness coefficient which is related to force and displacement vector at each node. In this paper, the authors formulate vibration analysis algorithm for a complex and large lattice type structure using the transfer of the dynamic stiffness coefficient. And the validity of TDSCM demonstrated through numerical computational and experimental results.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.209-216
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• 2000

The purpose of this study is to investigate elasto-plastic behaviour and estimate ultimate resistance capacity of the residential-commercial building subjected to lateral force along the height of structure. Four types of residential-commercial building are chosen as analytical models and investigated by pushover analysis. Pushover analysis estimates initial elastic stiffness, post-yielding stiffness, and plastic hinges on each story of structures through three-dimensional nonlinear analysis program CANNY-99. Skeleton curve of bending stiffness model is bilinear, shear stiffness model is trilinear, and axial stiffness model is elastic. Skeleton curve of axial stiffness model has the axial compression and tension stiffness of reinforced concrete members. This study presents the change of inter story drift, story stiffness and hinge of story and member.

• Journal of the Korea Convergence Society
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• v.7 no.4
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• pp.181-190
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• 2016

The objective of this study is to find the effective stiffness and compressive strengths of a unit-cell pinwheel truss and double pinwheel truss model designed following a double helical geometry similar to that of the DNA (deoxyribonucleic acid) structure in biology. The ideal solution for their derived relative density is correlated with a ratio of the truss thickness and length. To validate the relative stiffness or relative strength, ABAQUS software is used for the computational model analysis on five models having a different size of truss diameter from 1mm to 5mm. Applied material properties are stainless steel type 304. The boundary conditions applied were fixed bottom and 5 mm downward displacement. It was assumed that the width, length, and height are all equal. Consequently, it is found that the truss model has a lower effective stiffness and a lower effective yielding strength.