• Journal of the Korean Society for Precision Engineering
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• v.16 no.4 s.97
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• pp.26-36
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• 1999

A general procedure for determining the optimum location of suspension hard points with respect to kinematic design parametes is presented. Suspensions are modeled as connection of rigid bodies by ideal kinematic joints. Constraint equations of the kinematic joints are expressed in terms of the generalized coordinates and hard points. By directly differentiating the constraint equations with respect to the hard points, kinematic sencitivity equations are obtained. In order to cope with algebraic complexity associated with the differentiation process, a symbolic computation technique is used. A performance index is defined in terms of static design parameters such as camber, caster, toe, ect.. Gradient of the performance index can be analytically computed from the kinematic sensitivity equations. Optimization results show the effectiveness and validity of the procedure, which is applicable to any type of suspension if its kinematic configurations are given.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.251-258
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• 2001

Cable and membrane structures can be classified as a unstable structure in the view point of shape determination process. An unstable stucture at the initial state generally cannot take a role as the resistance for the external force. Therefore, there should be a stabilizing process to get the stable state of a structure and it is necessary to visualize the shape finding from unstable state to stable state. In this paper, a numerical method of stabilizing procedure for the link structures is presented. The structures are assumed to have rigid movements and thus only changing of the topology of member is considered during the analysis. The generalized inverse matrix and the principle of minimum potential energy are used in the process. Illustrative examples are presented and the results show good convergence.

• Structural Engineering and Mechanics
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• v.6 no.4
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• pp.411-425
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• 1998

The effective length factor of a framed column may be determined by means of the alignment chart procedure. This method is based on many unrealistic assumptions, among which is that all columns have the same stiffness parameter, which is dependent on the length, axial load, and moment of inertia of the column. A new approximate method is developed for the determination of effective length factors for columns in unbraced frames. This method takes into account the effects of inelastic column behaviour, far end conditions of the restraining beams and columns, semi-rigid beam-to-column connections, and differentiated stiffness parameters of columns. This method may be implemented on a microcomputer. A numerical study was carried out to demonstrate the extent to which the involved parameters affect the K factor. The beam-to-column connection stiffness, the stiffness parameter of columns, and the far end conditions of restraining members have a significant effect on the K factor of the column under investigation. The developed method is recommended for design purposes.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.692-695
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• 2010

일반적으로 모델개선에서는 부재단위의 강성을 파악하기 때문에 구조물의 취약부인 부재단부의 손상이 집중될 경우 손상의 형태를 세밀히 파악하기 어려우며 손상된 구조물의 거동을 정확하게 모사하기 어려운 단점이 있었다. 이를 해결하기 위해서는 부재 단부에 발생한 손상을 고려할 수 있는 좀 더 정밀한 해석 모델을 통한 모델개선이 필요하다. 본 연구에서는 부재 단부에 반강접 접합을 가지는 해석모델을 사용해 모델 개선을 실시하고 이를 통해 접합부의 손상 평가와 손상 구조물의 거동을 파악하였다. 제안된 방법을 5층 1경간의 RC 벽식 실험체의 손상탐지에 적용하였으며 그 결과 부재단위 모델을 사용할 때보다 더욱 정확하게 구조물의 손상을 평가하고 거동을 모사할 수 있었다.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.465-468
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• 2004

The first thing in remodelling of an apartment is the enlargement of living area, which is usually attained through extending balcony or corridor to the outside of the building. As a reasonable solution to the extension of floor a method of rigid connection in which steel bars are injected into the existing slab and concrete of newly building slab is installed with proper reinforcement is proposed in this research. To verify the structural performance of the method bending tests have been carried out for seven slab specimens.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.671-678
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• 2006

In this study, to describe vehicle-structure dynamic interaction phenomena with 1/4 vehicle model, nonlinear Hertzian contact spring and nonlinear contact damper are adopted. The external loads acting on 1/4 vehicle model are selfweight of vehicle and geometry information of running surface. The constraint equation on contact surface is implemented by the Penalty method with stabilization and the reaction from constraint violation. To describe pitching motion of various vehicles two types of the displacement constraint equations are exerted to connect between car bodies and between bogie frames, i.e., the rigid body connection and the rigid body connection with pin, respectively. For the time integration of dynamic equations of vehicles and structure Newmark time integration scheme is adopted. To reduce the error caused by inadequate time step size, adaptive time-stepping technique is also adopted. Thus, it is expected that more versatile dynamic interaction phenomena can be described by this approach and it can be applied to various railway dynamic problems with low computational cost.

• Structural Engineering and Mechanics
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• v.41 no.2
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• pp.183-204
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• 2012

Several issues regarding the structural idealization of steel buildings with perimeter moment resisting steel frames (MRSFs) and interior gravity frames (GFs) are studied. Results indicate that the contribution of GFs to the lateral structural resistance may be significant. The contribution increases when the stiffness of the connection of the GFs is considered and is larger for inelastic than for elastic behavior. The interstory shears generally increase when the connections stiffness is taken into account. Resultant stresses at some base columns of MRSFs also increase in some cases but to a lesser degree. For columns of the GFs, however, the increment is significant. Results also indicate that modeling the building as planes frames may result in larger interstory shears and displacements and resultant stresses than those obtained from the more realistic 3-D formulation. These differences may be much larger when semi-rigid (SR) connections are considered. The conservativism is more for resultant stresses. The differences observed in the behaviour of each structural representation are mainly due to a) the elements that contribute to strength and stiffness and b) the dynamics characteristics of each structural representation. It is concluded that, if the structural system under consideration is used, the three-dimensional model should be used in seismic analysis, the GFs should be considered as part of the lateral resistance system, and the stiffness of the connections should be included in the design of the GFs. Otherwise, the capacity of gravity frames may be overestimated while that of MRSFs may be underestimated.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.1
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• pp.1-8
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• 2018

The purpose of this study is to implement modeling by applying the parametric technique to the atypical trusses of rigid retractable large space structures. The retractable large space structure requires a lot of time and skill in modeling nonlinear shapes or generating, interpreting, and reviewing many models by alternative. To solve these problems, we introduce firstly parametric modeling tool, secondly, we analyze the connection of atypical three-dimensional trusses of a rigid retractable large-space structure, and finally model it as parametric components of the developed trusses. Therefore, it is a future study to make effective modeling of the openable roof by developing the components that can realize the modeling of the truss classified by the opening and closing method, respectively.

• Journal of Korean Society of Steel Construction
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• v.10 no.2 s.35
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• pp.211-219
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• 1998

The objective of this study is to investigate the structural behavior of Concrete-Filled Tubular Column H-Beam End-Plate Connections with Penetrated HT-Bolts under monotonic load. Simple bending tests are carried out with 5 kinds of specimens including beam specimen. The parameters of these tests are the thickness (T=22, 26. 30mm) of End-plates and the diameter (M=20, 22mm) of bolts. From the tests, the increasing values of yielding strength and initial stiffness of each specimen were gained as the thickness of End-plates and diameter of bolts are increasing. And the application of Bjorhovde et al and Eurocode 3 classification method by non-dimensional moment-rotation curves to the connections showed that all of them are included in rigid region as far as initial stiffness is concerned and all of them are also rigid as far as ultimate strength.

• Journal of Korean Society of Steel Construction
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• v.11 no.2 s.39
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• pp.109-116
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• 1999

This paper presents an experimental study on the behavior of CFT Column to H-Beam Endplate Connections with penetrated H/T bolts under monotonic loading. The object of this study is to estimate accurately the effect about the thickness of endplate and the arrangement of H/T bolts which was not got a grip on the results reported in the previous paper. Main parameters are the thickness of endplates (12mm, 16mm) and the arrangemement of H/T bolts (EP1, EP2, EP3 Type). The experimental results compared and analysed. 1) The specimens were classified by Bjorhovde's and EC3's method. 2) A formula to predict the ultimate moment of connection was derived based on the T-stub model, and theoretical value $(_tM_u)$ computed by the formula corresponded to the experimental value $(_eM_u)$.