• Structural Engineering and Mechanics
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• 제10권1호
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• pp.1-15
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• 2000

It is inevitable that every space truss structure would be under some form of direct member loading. At least the structure self weight certainly affects the members directly, and in structures involving top concrete slabs or cladding, their weight is also likely to apply some lateral pressure on the members. In spite of that, direct member loading is usually ignored in space truss designs and assumed to lead only to a negligible effect on truss performance. This study is intended to explore this point and identify the actual effects that can arise from direct member loading, and eventually provide an answer to the question of whether the current design practice is satisfactory or certain modifications would be needed. After presenting two analytical techniques to allow the study of space trusses with laterally loaded members, the paper describes a wide parametric study involving practical-size space trusses with different configurations, aspect ratios, boundary conditions and number of chord panels.

• Advances in Computational Design
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• 제2권3호
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• pp.195-210
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• 2017

Simultaneous optimization of trusses which concurrently takes into account design variables related to the size, shape and topology of the structure is recognized as highly complex optimization problems. In this class of optimization problems, it is possible to encounter several unstable mechanisms throughout the solution process. However, to obtain a feasible solution, these unstable mechanisms somehow should be rejected from the set of candidate solutions. This study proposes triangular unit based method (TUBM) instead of ground structure method, which is conventionally used in the topology optimization, to decrease the complexity of search space of simultaneous optimization of the planar truss structures. TUBM considers stability of the triangular units for 2 dimensional truss systems. In addition, integrated particle swarm optimizer (iPSO) strengthened with robust technique so called improved fly-back mechanism is employed as the optimizer tool to obtain the solution for these class of problems. The results obtained in this study show the applicability and efficiency of the TUBM combined with iPSO for the simultaneous optimization of planar truss structures.

• 한국공간구조학회논문집
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• 제4권1호
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• pp.39-48
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• 2004

Generally, a structural system with large inextensional deformations, or in other words, non-strained deformation is called as 'Unstable Structure', Truss-linked structures, cable structures, membrane structures and movable structures as foldable space structures etc, are included in this category. In this paper, a dynamic analysis method for unstable structural systems is presented. Governing equations for dynamic analysis of unstable truss structures with inextensional displacements are derived. Because of singularity of inverse matrixin in practical analysis of unstable structure, the generalized inverse matrix is Introduced to resolve the singular problem. Also, the RREF technique is used to get the inextensional displacement mode. Two unstable truss structures are analyzed by using presented method. Damping is not considered. From the given results, it is known that proposed method is useful to figure out the dynamic behavior of unstable truss structures.

• Steel and Composite Structures
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• 제35권1호
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• pp.29-41
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• 2020

Cross-beams of modern through truss bridges are connected to truss chord at its nodes and between them. It results in variable rotational end restraint for cross-beams, thus variable bending moment distribution. This feature is captured in three-dimensional modelling of through truss bridge structure. However, for preliminary design or rapid assessment of service load effects such technique of analysis may not be available. So an analytical method of assessment of rotational end restraint for cross-beam of through truss bridges was worked out. Two cases - nodal cross-beam and inter-nodal cross-beam - were analyzed. Flexural and torsional stiffness of truss members, flexural stiffness of deck members and axial stiffness of wind bracing members in the vicinity of the analyzed cross-beam were taken into account. The provision for reduced stiffness of the X-type wind bracing was made. Finally, general formula for assessment of rotational end restraint was given. Rotational end restraints for cross-beams of three railway through truss bridges were assessed basing on the analytical method and the finite element method (three-dimensional beam-element modelling). Results of both methods show good agreement. The analytical method is able to reflect effects of some structural irregularities. On the basis of the obtained results the general values of rotational end restraint for nodal and inter-nodal cross-beams of railway through truss bridges were suggested.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.917-918
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• 2012

• Structural Engineering and Mechanics
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• 제26권3호
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• pp.251-262
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• 2007

This paper examines the application of artificial neural networks (ANN) to the response prediction of geometrically nonlinear truss structures. Two types of analysis (deterministic and probabilistic analyses) are considered. A three-layer feed-forward backpropagation network with three input nodes, five hidden layer nodes and two output nodes is firstly developed for the deterministic response analysis. Then a back propagation training algorithm with Bayesian regularization is used to train the network. The trained network is then successfully combined with a direct Monte Carlo Simulation (MCS) to perform a probabilistic response analysis of geometrically nonlinear truss structures. Finally, the proposed ANN is applied to predict the response of a geometrically nonlinear truss structure. It is found that the proposed ANN is very efficient and reasonable in predicting the response of geometrically nonlinear truss structures.

• 한국해양공학회지
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• 제17권5호
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• pp.57-65
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• 2003

This paper proposes an optimum design method of structural and control systems, using a 2-D truss structure as an example. The structure is subjected to initial static loads and disturbances. For the structure, a FEM model is formed. Using modal transformation, the equation of motion is transformed into modal coordinates, in order to decrease D.O.F. of the FEM model. To suppress the effect of the disturbances, the structure is controlled by an output feedback $H_{\infty}$ controller. The design variables of the combined optimal design of the control-structure systems are the cross sectional areas of truss members. The structural objective function is the structural weight. The control objective function is the $H_{\infty}$ norm, the performance index of control. The second structural objective function is the energy of the response related to the initial state, which is derived from the time integration of the quadratic form of the state in the closed-loop system. In a numerical example, simulations have been perform. Through the consideration of structural weight and $H_{\infty}$ norm, an advantage of the combined optimum design of structural and control systems is shown. Moreover, since the performance index of control is almost nearly optimiz, we can acquire better design of structural strength.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• 제6권1호
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• pp.60-68
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• 2003

This paper proposes an optimum design method of structural and control systems, using a 2-D truss structure as an example. The structure is subjected to initial static loads and disturbances. For the structure, a FEM model is formed. Using modal transformation, the equation of motion is transformed into modal coordinates, in order to decrease D.O.F. of the FEM model. To suppress the effect of the disturbances, the structure is controlled by an output feedback $H_{\infty}$ controller. The design variables of the combined optimal design of the control-structure systems are the cross sectional areas of truss members. The structural objective function is the structural weight. The control objective function is the $H_{\infty}$ norm, the performance index of control. The second structural objective function is the energy of the response related to the initial state, which is derived from the time integration of the quadratic form of the state in the closed-loop system. In a numerical example, simulations have been perform. Through the consideration of structural weight and $H_{\infty}$ norm, an advantage of the combined optimum design of structural and control systems is shown. Moreover, since the performance index of control is almost nearly optimiz, we can acquire better design of structural strength.

• 한국강구조학회 논문집
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• 제15권5호통권66호
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• pp.519-529
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• 2003

최근에 스틸하우스나 고층아파트 지붕에 경량형강 지붕트러스의 사용이 증가하는 추세이다. 그러나 현재 지붕트러스와 하부구조의 앵커 접합부의 설계는 거의 경험에 의존하는 실정이다. 본 논문에서는 냉간성형형강 지붕트러스 앵커 접합부의 구조적인 거동에 관한 실험적인 연구를 서술하였다. 트러스부재와 접합철물은 스크류로 접합하였으며, 하부구조의 구조재료에 따라 시공성 및 구조적인 성능이 우수한 단순한 형태의 접합철물을 사용하여 철근콘크리트구조인 경우 케미컬 앵커볼트 그리고 강구조인 경우는 용접 및 DX-Pin을 사용하여 하부구조와 연결하였다. 다양한 접합부 형태에 대한 인발실험을 수향하여 접합부의 강도 및 강성을 측정하였으며, 이를 AISI시방서(1996) AISC시방서(1989)규정에 근거한 설계강도와 비교하였다. 또한 스크류 연결부의 최대전단강도식을 제안하여 실험결과와 비교하였다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2001년도 학술대회지
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• pp.214-221
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• 2001

인천국제공항 교통센터의 Great Hall은 3차원의 입체적 곡면 Truss로 구성되어 있고, Great Hall Roof Truss는 최대 경간162m, 480Ton인 Truss을 포함한 13개의 Main Steel Truss로 구성되어 있다. Great Hall Roof Truss는 총 중량 6,300Ton, 9,600 Pieces로 1개의 절점당 최대 13개의 다른 부재가 접합하게 되어 있고, 12개의 Fabric 기초에 의해 지지된다. 경제적인 효과와 공기적 측면을 고려하여 기존 재래식(가설 Bent) 공법보다 Block화 공법 및 Sliding공법을 채택하였다. Roof 구조물은 3,550Ton과 2,700Ton 중량인 두 Block으로 나누고 구조물 외부에 설치 된 Giant Sleigh에 선 조립 후 Tandem Pulling Jack과 Strand를 이용하여 181m를 Sliding하여 본 구조물의 위치에 설치되었다.