• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.1
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• pp.53-63
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• 2016

Wheel dynamometers are used to measure dynamic load that is conveyed from the road to a vehicle while driving. In this paper, two types of six-component wheel dynamometers utilizing shear deformation and bending deformation were designed and evaluated. Prior to designing the shear and bending type wheel dynamometers, the shear and bending deformation behaviors of the basic structure of the wheel dynamometer itself were analyzed using finite element analysis. Strain analysis was performed repeatedly in order to obtain a similar output sensing strain for each load component. The design was modified with a bridge circuit in order to minimize coupling strain. The results indicated that the shear type dynamometer was expected to obtain stable characteristics due to uniform strain distribution while the bending type dynamometer was expected to obtain high-quality sensitivity performance due to consistent output sensitivity.

• Journal of the Korea Convergence Society
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• v.9 no.8
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• pp.179-184
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• 2018

The driving methods of car are front wheel drive, rear wheel drive and four wheel drive. At driving methods, constant velocity joint is the most important part at carrying out two functions for converting to the direction which the driver wants and transferring the power to wheels. At driving on the road, the impact can be applied to the parts transmitting power according to the state of road surface. In this study, each models of three constant velocity joints whose shaft length are different respectively were modelled with CATIA and the structural and fatigue analyses were carried out by using ANSYS. This study result is thought to be the useful material at designing the constant velocity joint with the durability against impact. And it is possible to be grafted onto the convergence technique at the design of constant velocity joint and show the esthetic sense.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.299-307
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• 2005

The 180 km/h Korean Tilting Train(TTX) which is now developing as a part of the Korean National R&D project, was elaborately designed. As the tilting trains run curve track with the $30\%$ higher speed than normal trains, the higher centrifugal and dynamic force are expected. Furthermore the complex tilting system increase the probability of failure. Therefore it is very important for tilting train to ensure safety against derailment under the various kind of failed condition in the middle of running as well as normal operating condition. The TTX train have the relatively high roll stiffness to improve the lateral ride comfort and to limit the roll displacement on the curve. But the higher roll stiffness increase the risk of derailment on the twisted track. This paper describes the study to review the safety against derailment caused by the wheel unloading on the severely twisted track. The worst combination of maximum cant change with maximum twist defect was established by numerical simulation. And also it was assumed that the air bag deflated and still the train run its speed limit. Those kind of assumption might be the worst case from the view point of wheel unloading derailment on the twisted track. The dynamic simulation was done by means of VAMPIRE S/W and non-linear transient analysis. We found that derailment quotients Q/P was only slightly influenced by track twist but the wheel unloading was greatly influenced. And we ascertained that the higher roll stiffness the higher wheel unloading. In case of air bag deflated situation, the wheel unloading reached up to $100\%$ which means the wheel lift or jumped. Therefore it was concluded that the design need to be improved to ensure the safety against derailment on the maximum twisted track in case of air bag deflated and tilting train's speed limit.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1229-1238
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• 2011

This paper deals with the lateral dynamic model of an all-wheel steered articulated vehicle to design a guidance controller. Nonlinear dynamic model of articulated vehicle is developed by complementing the model about the BRT system of California PATH in U. S. A. and the Phileas system of the APTS in Netherlands. Linear lateral dynamic model has been derived from the nonlinear dynamic model under some assumptions associated with the driving conditions. To design a guidance controller, we derive a transfer function that is steering angle as input and lateral acceleration as output from the linear lateral dynamic model by applying the parameter of vehicle that is developed by Korea Railroad Research Institute. To validate the dynamic model, nonlinear dynamic model has been compared with a vehicle model that has been programmed in ADAMS, and linear dynamic model has been compared with a nonlinear dynamic model under sime assumptions.

• Proceedings of the KSRS Conference
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• v.1
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• pp.290-293
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• 2006

COMS (Communication, Ocean and Meteorological Satellite) shall be operated with two remote sensing payloads, MI (Meteorological Imager) and GOCI (Geostationary Ocean Color Imager). Since both payloads have rotating mechanisms, the dynamic coupling between two payloads is very important considering the pointing stability during GOCI operation. In addition, COMS adopts a single solar wing to improve the image quality, which leads to the unbalanced solar pressure torque in COMS. As a result, the off-loading of the wheel momentum needs to be performed regularly (2 times per day). Since the frequent off-loading could affect MI/GOCI imaging performance, another suboptimal off-loading time needs to be considered to meet the AOCS design requirements of COMS while having margin enough in the number of thruster actuations. In this paper, preliminary analysis results on the pointing stability and the wheel off-loading time selection with respect to MI/GOCI operations are presented.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.100-107
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• 2005

The objective of the study is to improve the quality of wheel bearing hub by the rigid-plastic finite element analysis and the response surface methodology. The rigid-plastic finite element codes, AFDEX-2D and DEFORM-3D, were used to analyze the two-dimensional and three-dimensional forging processes, respectively. The response surface analysis is used to find the minimum underfill by the variation of design variables such as the height of billet after upsetting and punch angles of blocker dies. The metal flow of forged product shows good agreement with the results from 2D and 3D analysis. Also, the quality of the wheel bearing hub has been improved by the optimization of design variables and the machining time has been reduced by the machining allowance.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.179-186
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• 2001

As the freight traffic becomes heavier, the high speed of existing freight cars is essential instead of the construction of a new railway. The high speed can be achieved by the design modifications of the freight bogie. In this paper, an analytical model of freight bogie including the lateral force between rail and the flange of wheel is developed to decide the critical speed, which activates a hunting motion and tells the running safety of freight bogie. The dynamic responses of the analytical model were compared with an experimental data from a running test of a freight bogie and showed good agreements between them. The analytical model is used to find the design modifications of the freight bogie by parameter studies. The results show that the reduction of wheelset mass ratio and the increase of the axle distance of the freight bogie can increase the critical speed, but the primary lateral stiffness has little effects on the critical speed. And this also study shows that smaller wheel conicity deteriorates the running safety of the freight car, which means the overhauling of the wheel of freight bogie should be done regularly.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.2
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• pp.196-203
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• 2012

When manufacturing die casting mold, generally, the casting layout design should be considered based on the relation between injection system, casting condition, gate system, and cooling system. Also, the extent or the location of product defects were differentiated according to the various relations of the above conditions. High-qualified products can be manufactured as those defects are controled by the proper modifications or the changes of die casting mold with the conditions. In this research, the proper manufacturing method was derived intensively for reducing the defect of the internal porosity of steering wheel housing which is very complicated to achieve a good mold design. The method was also derived for minimizing and for guaranteeing the product quality through the analysis of the casting problem and the deduction of alternative plans.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.6
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• pp.50-54
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• 1999

In the process of designing a wheel balancer an ergonomic evaluation model has shown that manual tire handling onthe machine was often the major problem, The root of the problem lay in the design of machine's shaft which is influenced by the opeative handling task. Several methods were reviewed for determining the correct shaft' sizes but the Revised NIOSH Equation and the Lifting Stress Calculator were found to be the only suitable models for this study. An application of these mathematical models has shoed that the shaft length and the shaft height were the most critical measurement By analyzing these conclusion s the correct shaft size parameters became clearly defined.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.132-137
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• 2003

For the evaluation of acoustic noise of a DLP projector, vibration and sound characteristics of a DLP projector were studied. The acoustic noise of DLP projector could be classified into three categories, that is, the direct noise from a body of rotation, the air-bone noise generated from turbulence or vortex occurred during cooling process and the structural born noise produced by vibrating elements. Cooling fans and color filter wheel which rotates at 9000 rpm are main causes of acoustic noise induced in DLP projector. Since the structure of an optical module in a DLP projector can be excited by the excessive vibration of a color filter wheel, the structural design for anti-vibration should be considered. To make a reduction of overall acoustic noise, the anti-vibration design and the enclosing structure have been studied and applied to a color filter wheel.