• Advances in Computational Design
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• v.2 no.3
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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.

• Journal of Korean Association for Spatial Structures
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• v.4 no.1 s.11
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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.

• Korean Institute of Interior Design Journal
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• v.14 no.5 s.52
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• pp.10-17
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• 2005

This Study is concerned with the acceptance of Western timber structure and the interior space of church buildings in the early modern period in Korea. Timber roofs have represented a wide variety of constructional forms and have been fundamental to any technological appraisal of the evolution of both of Western and Eastern architecture. Especially the roof structure of the church buildings reflects the technological level, aesthetic sense, and spacial concepts of the age. Between Western timber structure and Korean timber structure, there are many differences in not only structural form but also form of roof, members, load, frame system and etc. And there were various types of framing technique such as timber truss, timber arch, timber vault in the western style church architecture in the early modern period in Korea. I have summarized the character of the acceptance process of Western timber structure and the influences on the interior space of church buildings.

• Journal of Korean Association for Spatial Structures
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• v.10 no.2
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• pp.95-103
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• 2010

This paper study on the accuracy improvement of nonlinear stiffness equation. The large structure must have thin thickness for build the large space structure there fore structure instability review is important when we do structural design. The structure instability of the shelled structure is accept it sensitively by varied conditions. This come to a nonlinear problem with be concomitant large deformation. Accuracy of nonlinear stiffness equation must improve to examine structure instability. In this study, space truss is analysis model Among tangent stiffness equation and nonlinear stiffness equation is using nonlinearity analysis program. The study compares an analysis result to investigate accuracy and convergence properties improvement of nonlinear stiffness equation.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.1
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• pp.73-80
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• 2012

It is important to design the optimal shape in the initial process because the influences on the design and construction are large according to the shape and pattern of spatial structures. However, the existing optimal shape designs for spatial structure are performed by the designer's intuition and experiences. Therefore, this study proposes the integrated process using the topology optimization and cellular automata model. First, the initial optimal shapes are obtained by using the topology optimization, and then the spatial truss structural patterns are created through the application of cellular automata rules. Finally, the optimal shapes to satisfy the various design conditions are generated by the structural analysis and size optimization.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1324-1329
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• 2009

Needs for underground space development and utilization have been increasing in urban area. The conventional strutting method in excavation is effective to restrain the ground movements and displacements of earth structures but inefficient for workers because of small working space. The conventional earth reinforcement methods such as earth-anchor and soil-nailing also have limitation to apply in urban area due to threats to stability of adjacent buildings around excavation boundaries. Recently, many types of earth retaining structures are being developed to overcome disadvantages of conventional excavation methods in urban area. In this study, a series of numerical analyses were performed with MIDAS GTS, geotechnical analysis program and MIDAS Civil, structural analysis design program to evaluate behavior and stability of the new type of non-supporting earth retaining structure, called Temporary Tower System (TTS), consisting of tower truss structures with much economical and spatial advantage.

• Journal of Aerospace System Engineering
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• v.16 no.4
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• pp.68-76
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• 2022

The purpose of this paper was to design the cable networks for mesh reflector antennas, considering the flexibility of structures. An effective form-find methodology is proposed. The whole parts of the cable networks are described by the absolute nodal coordinate formulation. Additionally, nonlinear deformation of the cable can be obtained. The form-finding analysis of the reflector with standard configuration is performed, to validate the proposed methodology. The truss ring structure is numerically modeled using the frame elements. To consider the flexibility of the truss ring as well as the cable net structure, an iteration analysis between the truss ring and the cable net under tensional forces is also performed in the form-finding process. The finial configuration of the reflector with tensioned cable networks is demonstrated.

• Journal of Korean Association for Spatial Structures
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• v.4 no.2 s.12
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• pp.63-71
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• 2004

The structural space is gradually wide and is wanting agreeable environment by the requirement and necessity of people who lives modem stage. The building coincides with such requirements and is the high rise building actual circumstances which is doing ultra-large. The confirmed report of the technology to organize great merit is becoming currently considerably important issue in constructing a building field. Thus, this paper examine closely for nonlinear unstable taking a picture uneasiness height of prosperity considering to initial imperfection by a numerical method with a space frame structure of discrete system in large space structure. Based on previous investigation method, this paper induce nodal stiffness matrix of solid truss elements considering geometrical nonlinear using finite element method. In this paper, three types of space structure considered; i) 1-free node space structure, ii) 2-free node space structure, iii) multi-free node space structure. It apply the above examples to a nonlinear program, next, grasp the characteristic of an unstable conduct and the result was a clearing low.

• Journal of Korean Association for Spatial Structures
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• v.12 no.2
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• pp.89-98
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• 2012

This study investigates the optimum structural design of space truss considering global buckling, and is to obtain the minimal weight of the structure. The mathematical programming method is used for optimization of each member by member force. Besides, dynamic programming method is adapted for consideration in snap-through buckling. The mathematical modeling for optimum design of truss members consists of objective function of total weight and constrain equations of allowable tensile (or compressive) stress and slenderness. The tangential stiffness matrix is examined to find the critical point on equilibrium path, and a ratio of the buckling load to design load is reflected in iteration procedures of dynamic programming method to adjust the stiffness of space truss. The star dome is examined to verify the proposed optimum design processor. The numerical results of the model are conversed well and satisfied all constrains. This processor is a relatively simple method to carry out optimum design with consideration in global buckling, and is viable in practice with respect to structural design.

• Smart Structures and Systems
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• v.11 no.1
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• pp.69-86
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• 2013

An efficient methodology using static test data and changes in natural frequencies is proposed to identify the damages in structural systems. The methodology consists of two main stages. In the first stage, the Damage Signal Match (DSM) technique is employed to quickly identify the most potentially damaged elements so as to reduce the number of the solution space (solution parameters). In the second stage, a particle swarm optimization (PSO) approach is presented to accurately determine the actual damage extents using the first stage results. One numerical case study by using a planar truss and one experimental case study by using a full-scale steel truss structure are used to verify the proposed hybrid method. The identification results show that the proposed methodology can identify the location and severity of damage with a reasonable level of accuracy, even when practical considerations limit the number of measurements to only a few for a complex structure.