• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2003.04a
• /
• pp.206-210
• /
• 2003

Machining of deep holes with conventional boring bars frequently induce chatter vibration because of their low dynamic stiffness which is defined as the product of static stiffness and damping of conventional boring bar materials. In addition, the specific stiffness ($E/{\rho}g$) of boring bars is more important than the static stiffness to increase the fundamental natural frequency of boring bars in high speed machining. Therefore, boring bar materials should have high static stiffness and high damping as well as high specific stiffness. The best way to meet requirements is to employ fiber reinforced composite materials for high speed boring bars because composite materials have high static stiffness, high damping and high specific stiffness compared to conventional boring bar materials. In this study, the dynamic characteristics of carbon fiber epoxy composite boring bars were investigated. From the metal cutting test, it was found that the chatter was not initiated up to the ratio of length to diameter of 10.7 at the rotating speed of 2,500 rpm.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.20 no.5
• /
• pp.36-43
• /
• 2012

In this work the mixing and flow characteristics of a vane-type static mixer were investigated numerically for the reduction of NOx in the SCR-system of the diesel engines. The mixer was located in the 57 times pipe diameter away from the inlet. The analysis were performed by changing such various parameters as vane shape, angles, blockage ratio and location of the vane. The flow structure through the mixer was characterized by uniformity index and pressure drop. The results show that uniformity index and pressure coefficient are substantially influenced by the vane shape, angle, blockage ratio and position of the vane of the mixer.

• 유공압시스템학회:학술대회논문집
• /
• 2010.06a
• /
• pp.18-24
• /
• 2010

Because of the increasing demand on the high precision and high response of a machinery, electronic control valves are widely adopted at various application fields. This paper studies on the static characteristic of a first-stage proportional pressure control valve. At first an experimental apparatus including hyd. pump variable speed inverter, pressure and data aquisition system was setted up with the experimental apparatus, various tests such as P-Q-W test, hyd, pump, dynamic, static, frequency response test of the proportional valve was carride out and the results are discussed.

• Korean Institute of Interior Design Journal
• /
• no.28
• /
• pp.265-265
• /
• 2001

The perceptual presentation of interior design is to represent an interior space planned by a designer as if people see it in reality. The perceptual presentation methods that have developed are perspectives, full-scale models, small-scale models, photography of models, video taping of models, computer images, computer animation, and virtual reality. The purpose of this study is to investigate limits of those perceptual presentation methods according to their characteristics. The methods have characteristics that are either static or dynamic and either monoscopic or stereoscopic. In terms of representing interior spaces and perceiving interior spaces, the dynamic characteristic is more helpful than the static characteristic because the dynamic characteristic provides consecutively changing views of interior spaces when people walk around within the spaces. The stereoscopic characteristic is more helpful than the monoscopic characteristic because the stereoscopic characteristic provides the binocular depth perception. Full-scale models, small-scale models, virtual reality that have dynamic and stereoscopic characteristics, are most effective. The next effective methods are video taping of models and computer animation that have dynamic and monoscopic characteristics. The last effective methods are perspectives and photography of models that have static and monoscopic characteristics. But the most effective methods can not be said that those are perfect because each of them still has limits. Designers have to consider the limits of each perceptual presentation method to find a way that shows their designs most effectively. To develop the perceptual presentation methods of interior design, researchers should focus on the helpful characteristics that are dynamic and stereoscopic.

• Korean Institute of Interior Design Journal
• /
• no.29
• /
• pp.265-272
• /
• 2001

The perceptual presentation of interior design is to represent an interior space planned by a designer as if people see it in reality. The perceptual presentation methods that have developed are perspectives, full-scathe models, small-scale models, photography of models, video taping of models, computer images, computer animation, and virtual reality. The purpose of this study is to investigate limits of those perceptual presentation methods according to their characteristics. The methods have characteristics that are either static or dynamic and either monoscopic or stereoscopic. In terms of representing interior spaces and perceiving interior spaces, the dynamic characteristic is more helpful than the static characteristic because the dynamic characteristic provides consecutively changing views of interior spaces when people walk around within the spaces. The stereoscopic characteristic is more helpful than the monoscopic characteristic because the stereoscopic characteristic provides the binocular depth perception. Full-scale models, small-scale models, virtual reality that have dynamic and stereoscopic characteristics, are most effective. The next effective methods are video taping of models and computer animation that have dynamic and monoscopic characteristics. The last effective methods are perspectives and photography each of models that haute static and monoscopic characteristics. But the most effective methods can nut be said that those are perfect because each of them still has limits. Designers have to consider the limits of each perceptual presentation method to find a way that shows their designs most effectively. To develop the perceptual presentation methods of interior design, researchers should focus on the helpful characteristics that are dynamic and stereoscopic.

• Journal of the Korean Ceramic Society
• /
• v.33 no.10
• /
• pp.1095-1100
• /
• 1996

• Proceedings of the KIEE Conference
• /
• 2004.07e
• /
• pp.126-129
• /
• 2004

This paper presents the way to analyze the static and dynamic characteristics of the Compound motor and 3 phase slip ring motor using VIS (Virtual Instrument System) and Agilent VEE, GUI(Graphics User Interface) tool. This method is composed of real time measuring of various characteristics, which can't measure using analog meter and analyzer, and presenting and analyzing the static and dynamic characteristics by table, which calculates the measured parameter. Also, this can apply to the various parts.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.8 s.179
• /
• pp.1949-1957
• /
• 2000

All the loads in the real world act dynamically on structures. Since dynamic loads are extremely difficult to handle in analysis and design, static loads are utilized with dynamic factors. The dyna mic factors are generally determined based on experiences. Therefore, the static loads can cause problems in precise analysis and design. An analytical method based on modal analysis has been proposed for the transformation of dynamic loads into equivalent static load sets. Equivalent static load sets are calculated to generate an identical displacement field in a structure with that from dynamic loads at a certain time. The process is derived and evaluated mathematically. The method is verified through numerical tests. Various characteristics are identified to match the dynamic and the static behaviors. For example, the opposite direction of a dynamic load should be considered due to the vibration response. A dynamic bad is transformed to multiple equivalent static loads according to the number of the critical times. The places of the equivalent static load can be different from those of the dynamic load. An optimization method is defined to use the equivalent static loads. The developed optimization process has the same effect as the dynamic optimization which uses the dynamic loads directly. Standard examples are solved and the results are discussed

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.670_671
• /
• 2009

This paper presents a optimum design process for static torque characteristics of the Claw-Poles PM Stepping Motor(CPSM). Since the shape of CPSM changes along with axial direction, CPSM should only be analyzed by 3D-FEM. But 3D-FEM needs too much computation time and computer resources. Therefore, it is essential to reduce the number of 3D-FEM analysis models. In this paper, two design factors which affect the static torque characteristics of CPSM were selected. Optimum design process was able to make progress by using Pattern Search Algorithm and 3D-FEM. Finally, optimized model was compared with a conventional model.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.38 no.12
• /
• pp.1033-1047
• /
• 1989

A finite element method for the analysis of magnetic fields with hysteresis characteristics is proposed. The method employs Preisach model to describe hysteresis of magnetic material, so that even multi-branch or minor-loop characteristics can be taken into account. The problem can be considered as the analysis of a nonlinear equation where magnetization depends not only on the present value of the magnetic field but also on the past values, and the problem can be solved by the iteration method. Measurements were carried out on soft ferrite EI core for the comparison with computer solution, and good agreements were obtained. is investigated. A theoretical approach to gait study is proposed in which the static stability margins for periodic gaits are expressed in terms of the kinematic gait formula. The effects fo the stride length on static stability are analyzed and the relations between static stability and initial body configurations are examined. It is shown that the moving velocity can be increased to some extent without affecting stability margins for a given initial body configuration. Computer simulations are performed to verify the analysis.