• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.4 s.175
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• pp.907-915
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• 2000

The movement of teeth and initial stress associated with the treatment of orthodontics have been successfully studied using the finite element method. To reduce the effort in preprocessing of finite element analysis, we developed two types of three-dimensional finite element models based on the standard teeth model. Individual malocclusions were incorporated in the finite element The movement of teeth and initial stress associated with the treatment of orthodontics have been successfully studied using the finite element method. To reduce the effort in preprocessing of finite element analysis, we developed two types of three-dimensional finite element models based on the standard teeth model. Individual malocclusions were incorporated in the finite element models by considering the measuring factors such as angulation, crown inclination, rotation and translations. The finite element analysis for the wire activation with a T-loop arch wire was carried out. Mechanical behavior on the movement and the initial stress for the malocclusion finite element model was shown to agree with the objectives of the actual treatment. Finite element models and procedures of analysis developed in this study would be suitably utilized for the design of initial shape of the wire and determination of activation displacements.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.69-76
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• 1998

Due to the drastic improvement of computer hardware and operating system, it is easy to break through the main defects of limited computer memory and processing time, etc. To keep up with this situation, this paper is focused on developing the preprocessor program with the input method based on vector graphic editor and the preprocessing technique including automatic node generation algorithm for the $\rho$-version finite element program. To develop this preprocessor program, the special data structure and the OOP(Object Oriented Programming) have been used by the Visual Basic 4.0. The Special data structure is proposed to describe the geometric data of node numberings and coordinates suitable for the $\rho$-version finite element program, which are quite different from the comvential h-version finite element program.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1990.10a
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• pp.40-46
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• 1990

This paper introduces a geometric modelling system adopted in a newly developed preprocessor for finite element analysis of three dimensional structures. The formulation is characterized by hierarchical construction of structural model which consists of control points, curves, surfaces and solids. Various surface and solid modeling schemes based on blending functions and boundary representation are systematized for finite element mesh generation. The modeling system is integrated with model synthesis and operations which facilitate modelling of complex structures.

• KCID journal
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• v.2 no.2
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• pp.10-19
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• 1995

In spite of their high availability in the field of water resources, finite element models generally require large amount of input data in which the preparation of them consists of complicated procedures and time consuming works. In addition, in case of a

• Korean Journal of Computational Design and Engineering
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• v.1 no.3
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• pp.189-202
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• 1996

Complex geometric shapes can be defined simply and efficiently by combining and operating various surface primitives. These primitives and their intersection curves are used in finite element mesh generation to form an easy and intuitive procedure for finite element modelling of curved surfaces. This paper proposes techniques of automatic mesh generation on surface primitives with arbitrarily shaped boundaries and control curves, which may be created by surface to surface intersection. A method of automatic mesh generation on plane, which was previously developed by the author, has been modified for application to the surface mesh generation. Owing to the mesh generation-wise differences between planes and surfaces, the surfaces should be transformed into conceptual plane so that the modified plane mesh generation method can be applied. Surface development, mapping and mesh reconstruction are the key techniques suggested in this paper. The selection of the technique to apply can be determined automatically on the basis of the developability, existence of singularity and other characteristics of the surfaces on which the mesh is to be generated. The suggested techniques were implemented into parts of mesh generation functions of the finite element software, MacTran. Their validity and practicality were manifested by the actual use of this software.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1994.04a
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• pp.25-32
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• 1994

The pre-processor for finite to element structural analysis considering the user-friendly device is developed by using GUI. This can be used on WINDOWS' environment which is realized the multi-tasking and the concurrency by object-oriented paradigm. Data input can be done easily through menu, dialog box, automatic stepwise input and concurrent representation with the structural geometry on multiple windows. It in designed to control integratedly the pre-processing, execution and the post-processing of the finite element structural analysis program on multiple windows, and input data can be seen with result outputs at the same time. In addition, the object-oriented programming environment makes convenient revision and addition of the program components for expanding the scope of analysis and making better user environment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.886-889
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• 2004

A simple macro triangle with drilling d.o.f.'s is proposed for plane stress problems based on IET(Individual element test) and finite element template. Three-node triangular element has geometrical advantages in preprocessing but suffers from bad performance comparing to other shapes of elements -especially quadrilateral. Main purpose of this study is to construct a high-performance linear triangular element with limited supplementary d.o.f.'s. A triangle is divided by three sub-triangles with drilling d.o.f.'s. The sub-triangle stiffness come from IET passing force-lumping matrix, so this assures the consistency of the element. The macro element strategy takes care of the element‘s stability and accuracy like higher-order stiffness in the F.E. template. The resulting element fits on the uses of conventional three-node. Benchmark examples show proposed element in closed form stiffness from CAS (Computer algebra system) gives the improved results without more computational efforts than others.

• Computational Structural Engineering
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• v.8 no.1
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• pp.161-172
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• 1995

An Integrated processing system for finite element structural analysis has been studied. It is designed to control integratedly the preprocessing, the execution and the postprocessing of a finite element structural analysis program on Windows. It becomes a better graphic user interface(GUI) for the concurrent representation of various inputs and outputs through the dialog-type on multi-windows by the multi-tasking and the object linking and embedding(OLE). Data input can be done easily through menus, dialog boxes and automatic stepwise inputs on the multiple windows, and then output results can be seen with input data on the same screen. Efficiency and validity of the system were examined by solving several numerical examples.

• Computational Structural Engineering
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• v.9 no.3
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• pp.145-155
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• 1996

This paper suggests a new algorithm of automatic mesh generation over planar domains with arbitrarily shaped boundaries and control curves. The algorithm is based on the method of recursively subdividing the domain by the path connecting, with minimum penalty value, two points on the super-loop, which consists of the boundaries and the control curves, The algorithm is not subject to any limitation on the shape of the domain, and its process can be fully automated. Therefore, this algorithm can be implemented into computer programs which require minimal user intervention while generating finite element meshes over complicated domains. This algorithm can also be easily extended for application to the generation of meshes over curved surfaces, or to the adaptive mesh generation.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.04a
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• pp.79-86
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• 1997

In this study, pre-postprocessing toolbox is developed to perform elasto-plastic analyze of underground structures with transient ground water flow. This toolbox is composed of three modules. The first is the data input processor for the structural analysis. The preprocessing Is using GUI (Graphic User Interface), which is consist of dialog box, pull down, and short-cut icon, etc. The second is the structural analysis module. The analysis is based on the elasto-plastic finite element method involving additional options such as ground excavation effect, transient ground water flow, and rock bolts behavior. The last is the postprocessing module. The postprocessing is able to verify the result of the structural analysis by the graphical simulation which visualizes the element mesh, the node displacements, the element stress states, the stress contour, the ground water surface, and the rock bolt stresses. Since various options are considered separately in this toolbox, it is easy to modify the module of each processing, and to update other functional modules for the given analysis conditions.