• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.113-116
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• 2003

Hem quality can be determined mainly by turn-down and roll-in. Turn-down, that is created by the elastic recovery, can't be easily detected and measured since it is usually as small as 0.03 m. This study is focused on the precise evaluation of the hemming defects through analytical and experimetal approaches, and on the investigation of the influence of process parameters on the final hem quality. Implicit finite element analysis of plane-strain hemming process is performed by using a commercial code ABAQUS/Standard. Experiment and measurement is also carried out for steel and aluminium sheet metals, and the results are compared with those of analysis.

• 대한기계학회논문집A
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• 제30권4호
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• pp.428-434
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• 2006

Pulse laser welding of AISI 304 stainless steel plate was simulated to find optimal welding conditions by using commercial finite element code MARC. Due to geometric symmetry, a half model of AISI 304 stainless steel plate was considered and user subroutines were applied to boundary condition for the heat transfer. Material properties such as conductivity, specific heat, mass density and latent heat were given as a function of temperature. A moving heat source was designed on the basis of experimental data. As a result, Nd:YAG laser welding for AISI 304 stainless steel was successfully simulated and it should be useful to determine optimal welding condition.

• 한국소음진동공학회논문집
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• 제13권4호
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• pp.290-299
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• 2003

This paper presents an efficient modeling and dynamic analysis method for open cracked rotor bearing systems. An equivalent bending spring model is introduced to represent the structural weakening effect in the presence of cracks. The proposed modeling method is validated through a series of simulations and experiments. First, the proposed method Is rigorously compared with a commercial finite element code. Then, an experiment is performed to validate the proposed modeling method. Finally, a numerical example is introduced to demonstrate the possible application of the proposed method in the crack diagnosis for rotor systems.

• 한국정밀공학회지
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• 제17권12호
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• pp.88-93
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• 2000

The reduction of the cushion material such as Expanded Polystyrene (EPS) is one of the urgent tasks of the package design process in home electrical appliances considering environmental protection. EPS reduction often causes the structural damage of products, which must be protected in the environment of transportation. CAE simulation can help the efficient package design with low material cost. The mechanical drop simulation of packaged product was performed with commercial FEM code and Taguchi approach was used partially to determine the dominant design parameters. As results of this study, about 20% reduction of EPS was accomplished in the monitor package design.

• 한국정밀공학회지
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• 제14권9호
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• pp.45-51
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• 1997

For semi-solid forging, it is necessarily required to prepare a workpiece with globular microstructure. Among several processes to obtain golbular microstructure, SIMA process is very simple and advantageous with respect to equipment. This paper presents the influence of effective strain on the globularization with aluminium 2024 alloy in cold working stage by SIMA process. Upsetting and forward extrusion are tested for cold working and induction heating is also carried out for reheating to obtain golbular microstructure. Microstructure is observed with an optical microscope. And finite element simulations to obtain effective strain in cold working stage are performed by using commercial finite element code, DEFORM.

• 한국기계가공학회지
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• 제10권4호
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• pp.57-63
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• 2011

The aim of this study is to analyze turning process using commercial FEM simulation code. Various simulation models of orthogonal cutting process for 3 layers of metallic material have been simulated and analyzed. The workpiece material used for the orthogonal plane-strain metal cutting simulation consists of three layers, which are Allow Tool Steel, Aluminum and Stainless Steel. The finite element model is composed of a deformable workpiece and a rigid tool. The tool penetrates through the workpiece at a constant speed and constant feed rate. As an analytical result, detailed cutting temperature, strain, pressure, residual stress for both a tool and each layer of workpiece were obtained during the turning process. It has been closely observed that the chip flow curve deforms continuously.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.762-767
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• 2007

As a macromolecule material, melted rubber flow shows characteristics of shear thinning fluid. The dynamic viscosity of this rubber fluid is influenced by temperature and shear strain rate. In this study, the numerical simulation of rubber extrusion forming process has been performed using commercial CFD code, Polyflow. Power-law model considering the effect of shear rate is used for the computer simulation of this non-Newyonian flow. Also Non-isothermal behavior is considered as Arrhenius-law model. Distributions of velocity and temperature are predicted through the simulation.

• 한국생산제조학회지
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• 제22권6호
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• pp.963-968
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• 2013

In this study, we carried out a structural analysis for determining the stresses acting on the tempered glass of a freely falling cellular phone using ANSYS 13.0, commercial finite element code. We designed a phone heavier than any contemporary cellular phone and performed finite element analysis using the falling speed at a height of 104 cm, which is equal to of the average leg length of Koreans. By determining the maximum stress acting on the phone's tempered glass and frame, we identified the location of large deformation. Furthermore, we evaluated the maximum/minimum equivalent stress and deformation of the reinforced glass and frame as functions of time.

• Structural Engineering and Mechanics
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• 제37권5호
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• pp.509-527
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• 2011

The paper investigates the dynamic buckling behaviour of a laminated composite stiffened cylindrical shell using the commercial finite element code ABAQUS. The numerical model of the composite shell is validated by static tests. In particular, the experimental collapse test is numerically simulated by a quasi static analysis carried out by both ABAQUS/Standard and ABAQUS/Explicit. The behaviour in the post-buckling field and the collapse load obtained by the analyses are close to the experimental data. The validated model is then used to study the dynamic buckling behaviour with ABAQUS/Explicit. The effects of the loading magnitude and of the loading duration are investigated, implementing in the analysis also first-ply failure criteria. It is observed that the dynamic buckling load is highly affected by the loading duration.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.179-182
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• 2003

This research aims to establish an optimal design method of filament wound structures. So far, most design and manufacturing of filament wound structures have been based on manufacturing experiences, and there is no established design rule. In this research, possible winding patterns considering the windability and the slippage between fiber and mandrel surface were calculated using the semi-geodesic path algorithm. In addition, finite element analyses using a commercial code, ABAQUS, were performed to predict the behavior of filament wound structures. On the basis of the semi-geodesic path algorithm and the finite element analysis method, filament wound structures were designed using the genetic algorithm.