• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1061-1064
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• 2006

Optimal design of functionally graded plates is investigated considering stress and critical temperature. Material properties are assumed to be temperature dependent and varied continuously in the thickness direction. The effective material properties are obtained by applying linear rule of mixtures. The 3-D finite element model is adopted using an 18-node solid element to analyze more accurately the variation of material properties and temperature field in the thickness direction. For stress analysis, the tensile stress ratio and compressive stress ratio of the structure under mechanical load are investigated. In the thermo-mechanical buckling analysis, temperature at each node is obtained by solving the steady-state heat transfer problem and Newton-Raphson method is used for material nonlinear analysis. Finally, the optimal design of FGM plates is studied for stress reduction and improving thermo-mechanical buckling behavior, simultaneously.

• 소성∙가공
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• 제32권6호
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• pp.321-328
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• 2023

To ensure driver safety, high-strength steel pipes are utilized in the chassis and internal structures design of automobiles. ERW(electric resistance welding) pipes, fabricated through welding at joints using electrical resistance, form a Heat-Affected Zone (HAZ) during the welding process. Due to characteristics such as increased hardness and reduced ductility compared to the base material, HAZ poses challenges in finite element analysis (FEA) for pipe shapes. In this study, for FEA considering HAZ properties, mechanical properties were measured through uniaxial tensile testing and digital image correlation (DIC) techniques after specimen fabrication. These measurements were validated using reverse engineering methods. Furthermore, hardness measurements and gaussian functions were employed to ascertain the hardness distribution within the HAZ, serving as a basis for subdividing the HAZ and modeling the pipe shape. To validate the effectiveness of the HAZ modeling approach, models were interpreted incorporating only base material properties and models incorporating average-calculated HAZ properties. Comparative analysis was performed, revealing that the model subdividing the HAZ based on hardness measurements closely approximated experimental values. This validation offered a methodology for HAZ modeling in FEA.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2007년 가을학술발표회
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• pp.305-316
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• 2007

Free field ground motion during earthquake is significantly affected by the local soil conditions and it is essential for the seismic design to perform the site specific ground response analysis. So, Round Robin Test (RRT) on ground response analysis was performed for three sites in Korea. A total of 12 teams presented the results of ground response analysis with used input soil properties based on own judgement. In this paper, the results of one dimensional equivalent linear analysis presented by 11 teams were compared to evaluate the effect of input soil properties on ground response analysis. Additionally, 4 influence factors on ground response analysis, that is shear wave velocity of soil layer, nonlinear dynamic deformational characteristics, bedrock depth and bedrock velocity were studied for assumed simple soil conditions.

• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.385-390
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• 2008

For taking account of the two-dimensional magnetic properties of a grain-oriented electrical steel sheet, the effective anisotropic tensor reluctivity is examined, and a computationally efficient algorithm is suggested by using the response surface method to model the two-dimensional magnetic properties. It is shown that the reconstructed two-dimensional magnetic properties are fairly effective to stabilize the convergence characteristics of the Newton-Raphson iteration in the nonlinear magnetic field analysis.

• 한국기계가공학회지
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• 제18권12호
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• pp.28-37
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• 2019

Due to their flexible tailoring qualities, composites have become fascinating materials for structural engineers. While the research area of fiber-reinforced composite materials was previously limited to synthetic materials, natural fibers have recently become the primary research focus as the best alternative to artificial fibers. The natural fibers are eco-friendly and relatively cheaper than synthetic fibers. The main concern of current research into natural fiber-reinforced composites is the prediction and enhancement of the effective material properties. In the present work, finite element analysis is used with a numerical homogenization approach to determine the effective material properties of jute fiber-reinforced epoxy composites with various volume fractions of fiber. The finite element analysis results for the jute fiber-reinforced epoxy composite are then compared with several well-known analytical models.

• 한국식생활문화학회지
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• 제29권6호
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• pp.637-647
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• 2014

This study was conducted to examine the physicochemical properties and consumer acceptability of commercial Gang-jeong. The samples used in this study were nine different Gang-jeong as commercial products. To accomplish this research, the physicochemical properties of nine samples, including moisture, crude lipid, sugar contents, acid value, color values, and texture, were measured. In addition, consumer panels evaluated the overall acceptability, appearance, flavor, sweetness, and texture of samples using a 9-point Likert type scale as well as the perceived intensities of sweetness and rancid odor by a 9-point Just-About-Right (JAR) scale. All data were statistically analyzed using One-way ANOVA, Principle Component Analysis, Hierarchical Cluster Analysis, and Pearson's Correlation Analysis. All physicochemical properties were significantly different among the samples (p<0.001). Analyses of consumer acceptability and JAR ratings of the nine samples showed significant differences (p<0.001).

• Structural Engineering and Mechanics
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• 제58권2호
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• pp.217-230
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• 2016

Effects of temperature dependent material properties on mixed mode fracture parameters of functionally graded materials subjected to thermal loading are investigated. A domain form of the $J_k$-integral method including temperature-dependent material properties and its numerical implementation using finite element analysis is presented. Temperature and displacement fields are calculated using finite element analysis and are used to compute mixed mode stress intensity factors using the $J_k$-integral. Numerical results indicate that temperature-dependency of material properties has considerable effect on the mixed-mode stress intensity factors of cracked functionally graded structures.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.389-392
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• 2005

In the modern days, a galvannealed sheet steel(GA) instead of a cold rolled steel sheet has been widely used as an alternative to extend the life of automotive body. Accordingly, the mechanical properties of GA for automobiles were taken Into account and studied by comparing with the temperature variation on annealing in this study. To clarify the effect of surface features in the mechanical properties of GA, the several tests such as nanoindentation and FE-analysis were executed. For this goal use is made of the method of neural networks. The developed neural networks apply also to obtain reliable mechanical properties of the thin films. Load-displacement curve was computed by the analysis procedure and compared with experimental results.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.93-100
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• 2002

Vertical reinforcement of soft soils using the deep mixing method has received increasing applications. In this study, the theory of elasticity and plasticity including the upper bound theorem of limit analysis were used to derive the equations for obtaining composite elastic properties and shear strength parameters. The developed equations were validated using the finite element computer program SAGE CRISP. The analysis involved 4 different cases-two different type of soil and replacement ratios. Tile results of the analysis show that the proposed equations could determine the properties of composite material for practical applications.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.3159-3162
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• 2008

A sensitivity analysis of the liquid rocket engine has been made. A mode analysis program is used to predict the performance change due to the variation of rocket engine operating environment. The propellant supply pressure and density are the major variables of the operating condition. The material properties of the turbine driving gas is assumed as the function of mixture ratio. The discrepancies of performance change between constant turbine driving gas properties and variable properties are greater for the case of fuel pump inlet pressure change than the oxidizer pump inlet pressure change.