• Advances in Computational Design
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• v.1 no.4
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• pp.345-356
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• 2016

Notwithstanding a considerable body of references in the literature on the buckling response of conical shell structures, it seems imperative to provide further insight on the buckling response of locally imperfect steel cones. This paper contains different simulations including non-linear FE analysis and discusses the influence of dent imperfection on the buckling load of these structures subject to external pressure. Data of the present work are evaluated against available experimental results, codes and recommendations and the effect of the local damages is exhaustively set forth. It is also found that the employed FE program can reliably predict the structural response of locally damaged conical shells.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.10a
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• pp.120-123
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• 2000

It is well known, for many years, that deep drawability can be improved by applying variable blank holding force. To apply variable blank holding force during cup during, we set up pressure controlling system on experimental hydraulic press, and the pressure control system is often called NC(Numerically Controlled) cushion system Using the NC cushion system we compared the drawability of square steel cups with NC cushion and that with conventional cushion. The results show drawability is greatly improved when the pressure control curve is designed in a S-shaped curve. This paper includes design details of the NC cushion system and experimental analysis of drawability with experimental NC cushion system.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.268-275
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• 2008

The prediction of hydrate pellet decomposition characteristics is required to design the regasification process of GTS (gas to solid) technology, which is considered as an economic alternative for LNG technology to transport natural gas produced from small and stranded gas wells. Mathematical model based on the conservation principles, the phase equilibrium relation, equation of gas state and phase change kinetics was set up and numerical solution procedure employing volume averaged fixed grid formulation and extended enthalpy method are implemented. Initially, porous methane hydrate pellet is at uniform temperature and pressure within hydrate stable region. The pressure starts to decrease with a fixed rate down to the final pressure and is kept constant afterwards while the bounding surface of pellet is heated by convection. The predicted convective heat and mass transfer accompanied by the decomposed gas flow through hydrate/ice solid matrix is reported focused on the comparison of spherical and cylindrical pellets having the same effective radius.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1923-1929
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• 2003

The present study investigated the microcirculation of blood in the left common artery (LCCA). In order to develop a mathematical model for microcirculation in LCCA, the present study adopted preexisted set of measured morphological data on anatomy, mechanical properties of the coronary vessels, viscosity of blood, the basic laws of physics, and the appropriate boundary conditions. In this study, the statistical distribution of blood pressure, blood flow, and blood volume in the LCCA were determined based on the anatomical branching pattern of the coronary arterial tree and the statistical data of blood vessel dimensions. Our calculations were in good agreement with the previous studies. The present results showed that the mean longitudinal pressure drop profile was function of the vessel order numbers. It was found that the normalized pressure drop was a logarithmic function of the compliance.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.5
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• pp.94-101
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• 2013

Injection molding process is one of the most important methods to produce plastic parts with high efficiency and low cost. The objective of this study is to implement the best plastic injection molding process for LED TV speaker frame. Moldflow analysis and simulation of plastic injection molding process were carried out in order to predict optimal modeling operation conditions and then injection molded part was produced various type of resin temperature, filling time and injection pressure variation. the result was that the best injection molding condition is set as 60bar pressure, 2sec filling time and $310^{\circ}C$ degree. The study result would be useful to variety of plastic injection molding process.

• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.268-275
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• 2008

The prediction of hydrate pellet decomposition characteristics is required to design the regasification process of GTS (gas to solid) technology, which is considered as an economic alternative for LNG technology to transport natural gas produced from small and stranded gas wells. Mathematical model based on the conservation principles, the phase equilibrium relation, equation of gas state and phase change kinetics was set up and numerical solution procedure employing volume averaged fixed grid formulation and extended enthalpy method are implemented. Initially, porous methane hydrate pellet is at uniform temperature and pressure within hydrate stable region. The pressure starts to decrease with a fixed rate down to the final pressure and is kept constant afterwards while the bounding surface of pellet is heated by convection. The predicted convective heat and mass transfer accompanied by the decomposed gas flow through hydrate/ice solid matrix is reported focused on the comparison of spherical and cylindrical pellets having the same effective radius.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.3
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• pp.58-69
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• 2000

An experimental study was conducted to investigate the influence of the spinning control cylinders which was set on the surface of a fixed circular cylinder in uniform flow, $Re=1.24\times10^4$. The measurements of velocity vectors and pressure distributions are carried out in various spin parameters and angles of spinning control cylinder. The results show that velocity profiles and pressure distributions are different with angles of control cylinder and spin parameters. When the control cylinder angle is $100^{\circ}$, there is more effect in increasing the velocity and the pressure distribution than other cases. In this case, the vortex shedding frequency was increased as increasing spin parameter.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.338-343
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• 2005

The Korean high speed train(KHST), developed since 1996, is presently undergoing commissioning tests on the high-speed track as well as on the conventional track since 2002. The purpose of the commissioning test is twofold: first to verify the performance of the train-set and equipments, and to demonstrate system reliability. Last December, KHST has reached the maximum speed of 350km/h and a number of data proving the performance of the train has been acquired. Among the data noise level and pressure variation in a cabin are important factors effecting passenger's comfort. Discussed in this paper are interior noise and pressure variation when the train passes tunnels during the 350km/h test.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.486-489
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• 2004

The NAH based on the inverse BEM is used to reconstruct the source field, which is advantageous in dealing with the irregular source. In the implementation of this technique, a large number of pressure measurements is required because an over-determined pressure data set is required. These conditions accordingly cause the increase of measurement time and associated effort along with the error due to mal-positioning. The purpose of this study is to reduce such inconveniences: Instead of increasing the number of field pressure data, the number of transfer paths between the source and the receiver is increased by placing rigid scattering body in-between the source and receiver. For validating the usefulness and effectiveness of the method, the numerical analyses of interior problem are demonstrated. As a result, it is thought that the proposed method enables the measurement at smaller number of sensor positions and the monitoring of surface vibration with less experimental effects than before.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.8
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• pp.777-782
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• 2007

Human Robot Interaction(HRI) through a haptic interface plays an important role in controlling robot systems remotely. The augmented usage of bio-signals in the haptic interface is an emerging research area. To consider operator's state in HRI, we used bio-signals such as ECG and blood pressure in our proposed force reflection interface. The variation of operator's state is checked from the information processing of bio-signals. The statistical standard variation in the R-R intervals and blood pressure were used to adaptively adjust force reflection which is generated from environmental condition. To change the pattern of force reflection according to the state of the human operator is our main idea. A set of experiments show the promising results on our concepts of human adaptive interface.