• Transactions of Materials Processing
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• v.23 no.4
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• pp.231-237
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• 2014

In the current study, a rate-dependent crystal plasticity finite element method (CPFEM) was used to simulate flow stress behavior and texture evolution of a body-centered cubic (BCC) crystalline material during plastic deformation at room temperature. To account for crystallographic slip and rotation, a rate-dependent crystal constitutive law with a hardening model was incorporated into an in-house finite element program, CAMPform3D. Microstructural heterogeneity and anisotropy were handled by assigning a crystallographic orientation to each integration point of the element and determining the stiffness matrix of the individual crystal. Uniaxial tensile tests of single crystals with different crystallographic orientations were simulated to determine the material parameters in the hardening model. The texture evolution during four different deformation modes - uniaxial tension, uniaxial compression, channel die compression, and simple shear deformation - was investigated based on the comparison with experimental data available in the literature.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.5
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• pp.339-345
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• 2021

Finite element analysis of the silo type underground opening for low- and intermediate-level radioactive waste (LILW) disposal facilities in Korea is presented in this study. The silo wall is circular and the roof is made up of domes. The silo wall is 25 meters in diameter, 35 meters in height, and the dome is 30 meters in diameter and 17.4 meters in height, and it is located at -80 meters to -130 meters at sea level. Although six silos have been constructed in the first stage and are in operation, only one silo was considered in this study. The two-dimensional axial symmetric finite element model, as well as the three-dimensional finite element model were made using the computer program SMAP-3D. Generalized Hoek and Brown Model was used for the numerical analyses. The finite element analysis of the silo type underground opening was carried out under various lateral pressure coefficients (defined as ratio of average horizontal to vertical in-situ stress), and the numerical results of these analyses were examined.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1301-1302
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• 2008

In this study, the fracture strength for fracture mechanism porous calcium phosphate made from sintered with ${\beta}$-tricalcium phosphate obtained by wet precipitation procedure is analyzed using finite element method and experiment measurement. First, three $3{\times}3{\times}3mm^3$ and $5{\times}5{\times}5mm^3$ specimens are prepared and tomographic images of one $5{\times}5{\times}5mm^3$ specimen are obtained by micro focus X-ray CT. The compression tests using the specimens are carried out to measure the elastic modulus and fracture strength to analyze the fracture mechanism of porous calcium phosphate specimen. The tomographic images are reconstructed by 3D reconstruction program. The finite elements are directly built up in the reconstructed specimen. The numerical simulation for the compression tests is performed using the element. The mechanism of calcium phosphate of simulation are obtained by the compression tests using there cylindric specimen of height 19.5 mm and diameter 10 mm. From the results, the applicability of porous calcium phosphate is evaluated to care fracture and vacant bone of a patient as the reinforcement material.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.249-251
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• 2003

The ring-shaped electrodeless lamp is intended as a high efficacy replacement for the incandescent reflector lamp in many applications. Therefore, the line time of ring-shaped electrodeless fluorescent lamps is substantially higher than that of conventional fluorescent lamps and last up to 60,000 hours. In this paper, maxwell 3D finite element analysis program (Ansoft) was used to obtain electromagnetic properties associated with the coil and nearby structures. The electromagnetic emitting properties were presented by 3D simulation software operated at 250[kHz] and some specific conditions.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.38-42
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• 2000

In this study, the low velocity impact behavior of the composite laminates has been described by using 3 dimensional nonlinear finite elements. To describe the geometric nonlinearity due to large deformation, the dynamic contact problem is formulated using the exterior penalty finite element method on the base of Total Lagrangian formulation. The incremental decomposition is introduced, and the converged solution is attained by Newton-Raphson Method. The Newmark's constant-acceleration time integration algorithm is used. To make verification of the finite element program developed in this study, the solution of the nonlinear static problem with occurrence of large deformation is compared with ABAQUS, and the solution of the static contact problem with indentation is compared with the Hertz solution. And, the solution of low velocity impact problem for isotropic material is verificated by comparison with that of LS-DYNA3D. Finally the contact force of impact response from the nonlinear analysis are compared with those from the linear analysis.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.118-125
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• 2003

Seismic damage assessment program for containment structure is developed. The program has been established through the combination of inelastic seismic analysis program and 3-D animation program. Damage indices at finite element level and structural level have been introduced for the seismic damage assessment. The seismic damage assessment program makes it possible to analyze in real-time the actual resistance capacity and damage level of containment structure. It will be expected that the program enables to establish the measures more quickly under the earthquake event.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.4
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• pp.449-455
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• 2011

Recently, international collaborative research which was organized at Bhabha Atomic Research Centre in India, was conducted to develop for pressure capacity and nonlinear behavior of PHWR 1/4 scale nuclear containment building between experimental test and numerical code. In this paper, a nonlinear finite element analysis was carried out in order to predict ultimate pressure capacity and nonlinear behavior of the 1/4 scale containment building. The 1/4 scale containment building is consisted of basemat, cylinder wall, dome and 4-buttress. For the finite element analysis, commercial program ABAQUS was used. Finite element models including concrete, rebar and tendon have been developed for assessment of ultimate pressure capacity and failure mode for nuclear containment building. From the analysis results, first crack of the concrete, the yielding of the rebar and ultimate capacity pressure occurred at $1.6P_d$(design pressure), $3.36P_d$ and $4.0P_d$, respectively.

• Journal of the Korean Geotechnical Society
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• v.19 no.3
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• pp.93-104
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• 2003

The Disturbed State Concept (DSC) model, with simplified unloading/reloading formulation, is implemented in a nonlinear dynamic finite element program fur porous media named DSC_DYN2D. In this research, the DSC constitutive model is utilized using the HiSS model for relative intact (RI) part and the critical state model for the fully adjusted (FA) part in the material. The general formulation for implementation is developed. The cyclic loading tests from the field load test data on a pile segment were numerically simulated using the finite element program DSC_DYN2D and compared with field measurements and those from the previous analysis with the HiSS model. The DSC predictions show improved agreement with the field behavior of the pile compared to those from the HiSS model. Overall, the computer procedure with the DSC model allows improved and realistic simulation of the complex dynamic soil-structure interaction problems.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.36-39
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• 2001

Tubular hydroforming has attracted increased attention in the automotive industry recently. In this study, a professional finite element program for analysis and design of tube hydroforming processes has been developed, called HydroFORM-3D, which is based on a rigid-plastic model. With the developed program several hydroforming processes such as a tee extrusion, an automotive rear axle housing and lower arm are analyzed and designed. And also, the Oyane's ductile fracture integral I was calculated from the histories of stress and strain according to every element and then the forming limit of the hydroforming process could be evaluated. The pediction of the bursting failure and the plastic deformation during typical hydroforming processes shows to be reasonable so that this approach can be extended to other various tube hydroforming processes.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.7
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• pp.152-157
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• 2014

Pro-program function of Pro/E has been utilized to expedite the design process of bellows. Design parameters selected for bellows design are manipulated to obtain the shapes user specified. User-oriented function may automate the bellows design process and this function may enable to reduce the design time remarkably. Generated bellows solid model has been applied to study of design sensitivity and optimum design. Among the selected design parameters, thickness of bellows affects system response most. Control-ring installed bellows may reduce the stress and prove to be an effective element for heavy load. The finite element analysis results combined with 3D model generated by pro-program may provide the feasible design directions to the bellows designer.