• Proceedings of the Computational Structural Engineering Institute Conference
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• 1991.04a
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• pp.43-47
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• 1991

For the structural analysis of optimum form decision of 3-D free fort structure such as ship, plane, automobile, definition of versatile forms and comparision between them satisfying the design criterion, is essential. In this paper, three dimensional free-form structure and it's variation are defined and attempts were made to obtain geometric form information for structural analysis. The validity of the method ks been tested for a particular free-form model selected.

• Computational Structural Engineering
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• v.5 no.2
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• pp.79-85
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• 1992

For the structural analysis of optimum form decision of 3-D free form structure such as ship, plane, automobile, definition of versatile forms and comparision between them satisfying the design criterion, is essential. In this paper, 3-D free form structure and it's variation are defined and attempts were made to obtain geometric form information for structural analysis. The validity of the method has been tested for a particular free model selected.

• Journal of Korean Association for Spatial Structures
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• v.14 no.1
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• pp.51-59
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• 2014

Single layer free-form structures are being highlighted in the field of architecture due to its attractive shape. In these structures, node connecting system is very important because the node must resist bending and axial stress simultaneously. So the local and global stabilities of entire structure can be determined by the stiffness of node system. In this study, therefore, various types of bending test with axial force were performed. As a result, bending capacity with axial force of a new spherical node for free-form structure could be performed and structural capacities were checked to use in real structure.

• Journal of Korean Association for Spatial Structures
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• v.12 no.1
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• pp.77-85
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• 2012

The membrane structure maintains stable form by giving initial tension to ductile membrane and increasing the stiffness of exterior that is much adopted in the large span spatial structure by making its thickness thin. This kind of membrane structure has characteristic that can express free-form curve, so the selection of structural form is very important. So, this paper proposes the expression of free-form surface based on NURBS basis function and the finite element method considering geometrical nonlinearity for the deduction of large deformation result. Also, for minimizing the approximation of the surface that is derived from the form-finding result, the interface method that change finite element mesh to NURBS is proposed. So, the optimum surface of free-form membrane is derived.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.4-5
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• 2019

With recent advances in computer technology, the ratio of free-form building designs to those of the past is increasing gradually. However, the current technology of free-form structure is very low. The core technology for free-form building implementation is the manufacturing technology of FCP (Free-form Concrete Panel), which indicates an unformed outside, and through the development of FCP manufacturing technology, the construction technology of free-form architecture can be enhanced. The inside and outside of an free-form building should be represented by the designer's intended curvature, and the panel's thickness by segment should be constant. For this reason, the technology that keeps the thickness of panels constant during the FCP production process is a key technology that can improve the quality of FCP. In this study, a basic study on ways to maintain a constant thickness of FCP is conducted.

• Journal of the Korea Computer Graphics Society
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• v.6 no.4
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• pp.29-34
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• 2000

This paper classifies the structure of the intersection curve between a surface of extrusion and a free-form surface. Our algorithm computes the silhouette curve of the free-form surface with respect to the unique ruling direction of the surface of extrusion. By intersecting the silhouette curve and the base curve of the surface of extrusion, we can classify the topological structure of the intersection curve, and compute all singularities in the intersection curve. Moreover, we can determine which ruling lines of the surface of extrusion intersect the other free-form surface and how many times. This classification provides a robust and efficient method for computing the intersection curve.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.4
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• pp.632-638
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• 2002

Extensible 3D(X3D) is a software standard for defining interactive web and broadcast-based 3D content integrated with multimedia. The data size of Web3D representation based on polygon meshes is so large that transferring practical data fast is a hard problem. This paper proposes 3D object structure, a new framework for compact 3D representation with high quality surface shape. By utilizing a free form surface technique, qualified surface are transferred with limited amount of data size and rendered. 3D graphic structure can be regarded ad both polygon meshes and free form surfaces. Therefore, it can be easily integrated to existing Web3D data formats, for example VRML ＆ XML. 3D object structure also enables modeling free form surface shapes intuitively with polygon modeling like operations.

• Journal of Mechanical Science and Technology
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• v.18 no.9
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• pp.1529-1536
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• 2004

A structure is broken down into a number of substructures by means of the finite element method and the substructures are synthesized for the complete structure. The divided substructures take two types: fixed-free and free-free elements. The flexibility and stiffness matrices of the free-free elements are the Moore-Penrose inverse of each other. Thus, it is not easy to determine the equilibrium equations of the complete structure composed of two mixed types of substructures. This study provides the general form of equilibrium equation of the entire structure through the process of assembling the equilibrium equations of substructures with end conditions of mixed types. Applications demonstrate that the proposed method is effective in the structural analysis of geometrically complicated structures.

• Journal of Korean Association for Spatial Structures
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• v.10 no.2
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• pp.77-86
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• 2010

This paper provides background theories and numerical results of automatic finite element (FE) mesh generation for freeform discrete structures. The present method adopts the computer aided geometric design (CAGD) technique to overcome the limitation of case-sensitive traditional automatic FE mesh generator. The present technique involves two steps. The first one is to represent the shape of the structure using the geometric model based on the CAGD and the second one is to generate the discrete FE mesh of spatial structures over the geometric model. From numerical results, it is found to be that the present technique is very easy to produce the FE mesh for free-form spatial structures and it can also reuse some features of traditional automatic mesh generator in the process. Furthermore, it shows the possibility to be used for the shape optimization of large spatial structures.

• Journal of KIISE:Software and Applications
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• v.30 no.9
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• pp.850-861
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• 2003

When creating annotation information in a free~form environment, ambiguity arises during the analysis stage between geometric information and the annotations. This needs to be resolved so that the accurate creation of annotation information in a free-form annotation environment is possible. This paper identifies and analyzes the ambiguities, specifying methods that are tailored to each of the various contexts that can cause conflicts with free-form marking in a XML-based annotation environment. The proposed general method is based on context which includes various textual and structure information between free-form marking and the annotations themselves. The context information used is expressed in XML based DTD, within the paper. The results are printed and shared through a system specifically implemented for this study. The results from the implementation of the Proposed method show that the annotated areas included in the free-form marking information are more accurate, achieving more accurate exchange results amongst multiple users in a heterogeneous document environment.