• Magazine of the Korean Society of Agricultural Engineers
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• v.32 no.E
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• pp.59-66
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• 1990

Abstract The formulation of the probabilistic finite element method was briefly reviewed. The method was implemented into a computer program for frame analysis which has the same analogy as finite element analysis. Another program for Monte Carlo simulation of finite element analysis was written. Two sample structures were assumed and analized. The characteristics of the second moment statistics obtained by the probabilistic finite element method was examined through numerical studies. The applicability and limitation of the method were also evaluated in comparison with the data generated by Monte Carlo simulation.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.115-119
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• 2001

This paper presents development of a Finite Element Analysis program. The program was developed on the based of second-dimensional plane strain rigid plasticity finite element analysis and an implicit program is coded. The program was tested by being applied to the axisymetric hydrostatic bulge forming processes using the circle dies. By the Finite Element Analysis at the fluid in chamber and at the blank material, we could know that the hydrostatic bulge forming processes can be influenced of material, the diameter of product and the forming velocity The developed Finite Element Analysis program was approved by the analysis results about forming variables.

• Structural Engineering and Mechanics
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• v.4 no.2
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• pp.139-148
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• 1996

Vector algorithms and the relative importance of the four basic modules (computation of element stiffness matrices, assembly of the global stiffness matrix, solution of the system of linear simultaneous equations, and calculation of stresses and strains) of a finite element computer program for inelastic analysis of reinforced concrete shells are presented. Performance of the vector program is compared with a scalar program. For a cooling tower problem, the speedup factor from the scalar to the vector program is 34 for the element stiffness matrices calculation, 25.3 for the assembly of global stiffness matrix, 27.5 for the equation solver, and 37.8 for stresses, strains and nodal forces computations on a Gray Y-MP. The overall speedup factor is 30.9. When the equation solver alone is vectorized, which is computationally the most intensive part of a finite element program, a speedup factor of only 1.9 is achieved. When the rest of the program is also vectorized, a large additional speedup factor of 15.9 is attained. Therefore, it is very important that all the modules in a nonlinear program are vectorized to gain the full potential of the supercomputers. The vector finite element computer program for inelastic analysis of RC shells with layered elements developed in the present study enabled us to perform mesh convergence studies. The vector program can be used for studying the ultimate behavior of RC shells and used as a design tool.

• Journal of the Korea Concrete Institute
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• v.11 no.3
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• pp.181-192
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• 1999

The progressive failure following strain localization in concrete can be analyzed effectively using finite element modeling of fracture process zone of concrete with a finite element embedded discontinuity. In this study, a finite element with embedded discontinuous line is utilized for the analysis of progressive failure in concrete. The finite element with embedded discontinuity is a kind of discrete crack element, but the difficulties in discrete crack approach such as remeshing or adding new nodes along with crack growth can be avoided. Using a discontinuous shape function for this element, the displacement discontinuity is embedded within an element and its constitutive equation is modeled from the modeling of fracture process zone. The element stiffness matrix is derived and its dual mapping technique for numerical integration is employed. Then, a finite element analysis program with employed algorithms is developed and failure analysis results using developed finite element program are verified through the comparison with experimental data and other analysis results.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.2
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• pp.130-139
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• 1998

The finite element analysis program should be prepared to deal with many of newly arising engineering problems. The sequential structured programming technique does not make a finite element method so flexible. So far, the object oriented programming technique was studied as an alternative programming paradigm. However, most of the research were in the state of the evaluation of the possibility and the applicability of the object oriented method for a finite element program. In this study, a practical object oriented finite element analysis program, OOFE_ JAVA was developed and the result of the analysis on a rectangular clamped plate was shown. The objects which compose the OOFE_JAVA were applied to several engineering problem without any modification and it was concluded that the object oriented technique was appropriate for the development of a complex and large engineering system. And a virtual machine which Java language is using can be loaded on any kinds of computer which has java interpreter regardless of the platform on which the OOFE_JAVA was developed.

• Computers and Concrete
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• v.15 no.2
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• pp.279-304
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• 2015

In this study, reliability analyses of steel fiber reinforced concrete (SFRC) corbels based on stochastic finite element were performed for the first time in literature. Prior to stochastic finite element analysis, an experimental database of 84 sfrc corbels was gathered from literature. These sfrc corbels were modeled by a special finite element program. Results of experimental studies and finite element analysis were compared and found to be very close to each other. Furthermore experimental crack patterns of corbel were compared with finite element crack patterns and were observed to be quite similar. After verification of the finite element models, stochastic finite element analyses were implemented by a specialized finite element module. As a result of stochastic finite element analysis, appropriate probability distribution functions (PDF's) were proposed. Finally, coefficient of variation, bias and strength reduction (resistance) factors were proposed for sfrc corbels as a consequence of stochastic based reliability analysis.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.247-252
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• 1996

In the concrete structures, cracks occur in various causes and the cracks seriously affect the functions of structures. The analysis techniques of progressive crack in the concrete have been improved with the advance of numerical techniques. The discrete crack model used in finite element program for the analysis of progressive failure is very effective, but it can not be easily implemented into numerical procedures because of difficult handing of nodal points in finite element meshes for crack growth. This paper introduces one of the techniques which skips the difficulty. In this paper, the modeling of progressive failure using finite element formulation is explained for the analysis of concrete fracture. The discontinuous element using the discontinuous shape function and the dual mapping technique in the numerical integration are implemented into finite element code for this purpose. It is shown that developed finite element program can predict the quasi-brittle behavior of concrete including ultimate load. The comparisons of the analysis results with other data are also shown.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.319-322
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• 2003

For the analysis of leveling process by the 3-dimensional elastic-plastic finite element method, a finite element analysis program modeling large deformation of shell has been developed. This program fur analyzing large deformation of sheet during leveling includes spring-back analysis as well as efficient contact treatment between sheet and rolls of leveler. This is verified by the simple leveling experiment with 5 rolls at laboratory. Besides the leveling examples, problems within the category of large strain and rotation, such as 3-dimensional roll-up and gutter occurrence at continuous bending-unbending process are also tested for verification of the program. The residual curvatures of strip predicted by finite element analysis are within 20% error range of the experiment. The formation and direction of anticlastic curvature or gutter during bending-unbending under tension is predicted and this agrees with the experimental results.

• 한국공간정보시스템학회:학술대회논문집
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• 2004.05a
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• pp.230-237
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• 2004

In this study, equation of finite element is formulated to analyze relations of large deformation-small deformation considering geometrical nonlinear for membrane structure. Total Lagrangian Formulation(TLF) is introduced to formulate theory and equation of motion considering Triangular Constant Strain(TCS) element in finite, element analysis is formulated. Finite element program is made by equation of motion considering TLF. This study analyzed a variety of examples, so compared with the past results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.693-696
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• 2007

In this paper, vibration sources of an electric forklift are identified and the forklift vibrations are reduced by structural modification by using the finite element analysis. From some experiments, it is also found that resonances occur because the natural frequencies of the forklift exist in usual driving speed range. To vibration sources of the electric forklift, the modeling is designed by using a commercial 3D CAD program CATIA and the finite element model is designed by a using finite element analysis program ANSYS which can perform modal analysis of flexible mode. To shift the natural frequencies out side the driving speed range, the frame part, the connection parts between main body and loader are modified to increase stiffness. It is verified that considerable amount of vibration are reduced by the structural modification.