• Tribology and Lubricants
• /
• v.25 no.2
• /
• pp.96-101
• /
• 2009

In order to improve leakage characteristic, angled-circumferential-groove pump seal is suggested. CFD analysis using FLUENT has been performed to predict leakage and determine an optimum slanted-groove angle $\alpha$ which yields the best leakage reduction. The optimum value of $\alpha$ ranges from $45^{\circ}$ to $60^{\circ}$ and depends on the pressure difference of seal and number of grooves for the same groove geometry. The maximum leakage reduction ratio increases as increasing the pressure difference of angled-circumferential-groove pump seal with the optimum value of $\alpha$.

• 연구논문집
• /
• s.29
• /
• pp.185-194
• /
• 1999

The shape and thickness distribution according to the pressure-time curve were carried out using the FEM and experiment. Also, mechanical properties were investigated. The square cup parts have been formed with pressure-time curve generated by result of analysis. The tensile strength and elongation have been investigated according to applied pressure conditions using the tensile test specimen obtained from the superplastic formed cup. We can use to predict the shape of formed part under the applied pressure using the FEM analysis. In the case of optimum pressure condition, the thickness distribution and mechanical properties were improved. From this study, we can find the important of optimum pressure-time condition. We have investigated about the forming of airplane part and fuel tank for motorcycle. If the applied load used in boundary conditions was appropriate, the simulation result coincides with the formed part. However, it is very difficult to define the pressure condition in complicated shape. Thus, it is need to develop the optimum pressure condition for superplastic forming.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.634-638
• /
• 1997

The objectives of this research are to develop lumber and lower-thoracic pedicle fixation system for Korean patients. To achieve the aimed goals, first, optimized shape design process is performed, and finite element methods are applied to evaluate the mechanical strength of the developed fixation system. Second, appropriate machining experiments are carried out to develop optimum machining conditions for titan~um alloys those are known as one of the most difficult-to-cut material. As the results of this research, new pedicle screw system, considering the morphological characteristics of Korean patients, is developed by applying the finite element analysis, optimum shape processing method and optimize design algorithm.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1999.03b
• /
• pp.143-148
• /
• 1999

Design optimization is performed to calculated the draw-bead force for satisfying the design re-quirements. For an analysis tool a rigid-plastic finite element method with modified membrane element is adopted. response surface methodology is utilized for constructing the approximation surface for the optimum searching of draw bead force in sheet metal forming process. the algorithm developed is ap-plied to a design of the draw bead forces in a deep drawing process. The results show that the design of process parameters is applicable in complex metal forming analysis. It is also noted that the present algo-rithm enhances the stable optimum solution with small times of optimization iteration.

• Publications of The Korean Astronomical Society
• /
• v.8 no.1
• /
• pp.33-45
• /
• 1993

The variation of instrumental profile for the different scan speed of PDS is estimated as FWHM of the assumed Gaussian Profile. The effects of scan speed and scan aperture of PDS on the objective prism spectrum analysis are investigated for 8 combinations of scan speed and scan aperture. Amomg them. D1 apture with 15 csu is found to be the most optimum choice for measuring KISO objective prism film. We suggest the preliminary test study of the scan speed and aperture for the optimum use of PDS for any massive scan of spectra. The optimum scan speed and aperture depends on the dispersion of spectrum as well as the type of phtographic emulsion.

• Proceedings of the KSME Conference
• /
• 2001.06a
• /
• pp.913-919
• /
• 2001

In this study, fiber orientation of stiffener was conducted to increase buckling load or failure load in each case with a different design value and a different objective function for stiffened laminated composite panel of I-type under compression loading. Regarding each of buckling load or failure load as objective function, optimum design was carried out. In respect of optimum design, it was investigated that optimum shape for buckling could improve fail load for postbuckling, because it was difficult to investigate the optimization of postbuckling which need long analysis times for nonlinear analysis.

• Proceedings of the KSME Conference
• /
• 2000.11a
• /
• pp.351-356
• /
• 2000

The mechanical stress due to the wheel-rail contact and thermal stress due to the drag braking increase the incidence of wheel failure. So, firstly, stress analyses(mechanical, thermal and combined stress) of wheel plate are performed using 3-dimensional finite element method(FEM). Secondly, the optimum design of wheel plate is investigated in order to reduce weight of the wheel based on results of stress analysis. The optimum design is peformed using 2-dimensional axisymmetric F.E. model and its results are verified by 3-dimensional F. E. model.

• Journal of Korean Society for Quality Management
• /
• v.7 no.2
• /
• pp.22-28
• /
• 1979

The problem considered in this paper is to select the vital factor effect to the product quality through the experimental design and analysis of response surface, so as to control the quality improvement of industrial product. In this time, even through the mathematical model is unknown it could be applicable to control the quality of industrial products and to determine optimum operating condition for many technical fields, particulary, for industrial manufacturing process. When a set of data is available from an experimental design, it is often of interest 1:0 fit polynominal repression model in independent variables (eg, time, temperature, pressure, etc) the optimize the response variable (eg. yield, strength etc). This paper proposes a method known to obtain the optimum operating condition, and how to find the condition by using table of orthogonal array experiments, and optimization methodology of statistical model. A criterion can be applied determining to optimum operating conditions in manufacturing industry and improving the fit of response surface which may be used for prediction of responses and quality control of industrial products.

• Journal of the Korean Society of Tobacco Science
• /
• v.11 no.2
• /
• pp.211-224
• /
• 1989

10. Three major factors, freeness, filler and blend ratio that exercised considerable influence on physical properties of cigarette papers were chosen for the sake of their optimization at this experiment. An optimization of those above factors in paper manufacturing was investigated using response surface analysis. Optimum beating degree for Kenaf, Flax and NBKP showed around 72。SR, 68。SR and 85 SR, respectively, in considering of five quality index such as porosity, tensile strength, stretch, whiteness and opacity. The best blending ration of reciprocal pulps treated under optimum beating degree were diversified and combination scope of the bast fiber (Kenaf, Flax) to the NBKP was range from 30% to 65% in case of the Kenaf, from 25 to 40% in Flax at the same receipe. The optimum range of calcium carbonate content revealed 25%~30% in Kenaf mixed NBKP and 24%~31% in Flax mixed NBKP.

• Journal of KSNVE
• /
• v.6 no.1
• /
• pp.57-64
• /
• 1996

The objectiv of this paper is to offer the method of the optimum structural modification by fixing the stiffener on the structure. The vibrational characteristics of a open box type structure are analyzed by the sub-structure synthesis method and sensitivies of each sub-structure are calculated by sensitivity analysis method. The positions to modify are found and the quantities to change are obtained by optimization techniques. As the result, it was found that; (1) The sensitivites of the natural frequency could easily be calculated by the sensitivity analysis method and the optimum position to fix stiffeners could be found. (2) The exact size of stiffeners could be calculated by the optimum structural modification method and the natural frequency could be easily shifted to the objective value. (3) It could be confirmed that the stiffener is a effective tool for accomplishing structural modification.