• Journal of Advanced Marine Engineering and Technology
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• v.36 no.4
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• pp.490-496
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• 2012

The main object of this research is to minimize the shock effects which frequently result in fatal damage in offshore wind turbine on impact of barge. The collision between offshore wind turbine and barge is generally a complex problem and it is often impractical to perform rigorous finite element analyses to include all effects and sequences during the collision. On applying the impact force of a barge to the offshore wind turbine, the maximum acceleration, internal energy, and plastic strain are calculated for each load case using the finite element method. A parametric study is conducted with the experimental data in terms of the velocity of barge, thickness of the offshore wind turbine, and thickness and Mooney-Rivlin coefficient of the rubber fender. Through the analysis proposed in this study, it is possible to determine the proper size and material properties of the rubber fender and the optimal moving conditions of barge.

• Journal of Families and Better Life
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• v.25 no.6
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• pp.71-82
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• 2007

On this research we investigated variables affecting university students' time management and verify relationship between the time management and life satisfaction. 438 students at Korea National Open University in Seoul were questioned through questionnaires composed of 47 questions. Data was analyzed by t-test, one-way ANOVA, Duncan's multiple range test and Person's correlation. The variables affecting time management were religion(those who believe in organized religion vs. those who do not), individual income, family income, teaming experiences for time management and reading books related to time management. fender, age, marriage status and occupation didn't affect the time management of students. The relationships between time management and life satisfaction showed a little positive relation. Some proposals for future researches and practices are given.

• Transactions of Materials Processing
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• v.3 no.1
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• pp.84-96
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• 1994

Simulation of 3 dimensional large irregularly shaped stamping process by a dynamic approach, based on an explicit time integration scheme, has been shown to be highly efficient and robust in comparison to traditional, implicit, quasi-static ones. The objective of the work is to evaluate the results from explicit code in application to deep drawing of rectangular cup and stamping of automotive front fender, in which deformation, force, thickness distribution are calculated. The method of predicting spring back and formability by and explicit code are suggested and applied to the processes.

• Transactions of Materials Processing
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• v.17 no.7
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• pp.511-516
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• 2008

A drawbead die for the experimental determination of drawbead forces was newly introduced in this paper. While the conventional Nine's drawbead die inevitably includes effects of a blank holding force on the measured drawbead forces, the new drawbead die excludes it by removing the blank holder contact in the dieface. Therefore, the new drawbead die can provide more realistic drawbead forces without considering somewhat arbitrary effect of blank holder with the computational procedure of forming process. The drawbead opening force and restraining force obtained by adopting the two experimental dies were compared for the validation of accuracy in the FEM simulation of automotive fender forming process. The compared section strains and draw-ins confirmed that the present drawbead die provides better drawbead forces for an accurate FEM simulation of sheet metal forming process.

• Journal of Families and Better Life
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• v.24 no.5 s.83
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• pp.37-51
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• 2006

The purpose of this study was to investigate the effects of self-esteem and gender role attitudes on youth's psychological well-being. The subjects of this research were 408 young men and women. All respondents answered by self-report questionnaire. The data were analyzed with descriptive statistics, t-tests, Pearson's correlations, and multiple regressions. The major results of this study were as follows: (a) Self-esteem and psychological well-being of young men and women were high. (b) There were changes toward the non-traditional direction in gender role attitudes of the youth. The young women exhibited more non-traditional gender role attitudes than the young men. (c) Self-esteem and family socioeconomic status showed positive influences on the psychological well-being of youth. However, gender role attitudes were not associated with youth psychological well-being.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.6
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• pp.1810-1818
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• 1996

A new finite elemetn approach is introduced for direct prediction of bland shapes and strain distributions from desired final shapes in sheet metal forming. The approach deals with the geometric compatibility of finite elements, plastic deformation theory, minimization of plastic work with constraints, and a proper initial guess. The algorithm developed is applied to cylindrical cup drawing, square cup drawing, and fron fender forming to confirm its validity by demonstratin reasonable accurate numerical results of each problems. Rapid calculation with this algorithm enables easy determination of various process variables for design of sheet metal forming process.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.570-575
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• 2008

Flows are studied to understand the flow structure in the narrow region that any experimental approaches are hard to access, Effects on the vehicle commodities from the flows are anticipated in the point of aerodynamics and aero-acoustics. PowerFLOW, which was well validated commercial software, was used to simulate the flow field in the small region, for example, the inner region of the fender panel, the inner region around the front door and the inner region of the trunk lid. Flows in the narrow region could be origins of door sealing problem and dust piling problem.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.3
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• pp.68-74
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• 2001

In the drawing of large size automotive panels, elastic deflection of die components is induced by the contact force between them. The deflection is nonuniform and locally distributed, and results in nonuniform material flow. In order to arrange such a nonuniform die gap, a correcting operation, so called die spotting, is inevitable, which requires trial and error works and consuming time. A prediction of the bending deflection prior to a try-out must be useful to reduce the die spotting time. In this study, drawing process of a front fender is simulated first. and the deflection of the blank holder is calculated from the contact force imposing on th blank holder. The balance block heights ensuring a uniform deflection are optimized by the analysis and design of experiments.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.207-218
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• 1997

A new blank design method is introduced to predict the blank shape and the strain distribution in the sheet metal forming process. This method deals with only one step from the final shape to the initial blank using the ideal forming theory. Based on this theory, a three-dimensional membrane finite element code has been developed to design an initial blank in the sheet metal forming process. In this paper, the designs of initial blanks for forming a cylindrical cup, a rectangular cup, and a front fender are presented as examples. Also, it compares the two shapes, the target shape with the shape which is deformed from the initial blank using the FEM analysis code. The results illustrate the information that this direct design code is useful in the preliminary design state.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.4
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• pp.58-67
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• 1998

A sectional analysis of sheet metal forming process with an arbitrary tool shape is proposed in the present work. To improve the numerical convergence in the conventional membrane sectional analysis, the Bending Energy Augmented Membrane (BEAM) elements had been developed. The BEAM elements particularly improve the stability and convergence of the finite element method for the case of deep drawing. In this work, the FERGUBON spline (C$^2$-continuous) was used to fit the deformed mesh to smooth the given curves and calculate the local curvature of the deformed sheet. The fittings of the deformed sheet and tool surface profile ensure the stability and the convergence of the finite element analysis of highly nonlinear stamping processes. A center floor section and front fender section are analyzed to show the accuracy and robustness of the approach. The results obtained by the proposed approach are compared with the available experimental data.