• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.3
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• pp.451-458
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• 2012

This study aims at the structural analysis with fatigue according to the configuration of railway vehicle wheel. Maximum equivalent stress or deformation is shown at the lower face in contact with wheel and rail. As model B has the maximum stress or deformation which becomes lower than model A, model B is shown to have more durability than model A. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. In case of 'Sample history' with the average stress of 0 to $-10^{11}$ Pa and the amplitude stress of 0 to $10^{10}$ Pa, the possibility of maximum damage becomes 3%. This stress state can be shown with 6 times more than the damage possibility of 'SAE Bracket history' or 'SAE transmission'. The structural result of this study can be effectively utilized with the design of railway vehicle wheel by prevention and durability against its damage.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.6
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• pp.596-601
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• 2014

In this study, driving efficiency and the safety of motorcycle drivers due to the mounting gradient of motorcycle protective glass are investigated through flow analysis. Mounting gradients of motorcycle protective glass in models 1, 2, and 3 are $60^{\circ}$, $70^{\circ}$, and $80^{\circ}$, respectively. Wind velocity of 100 km/h is applied to the protective glass installed at the front of each model. The flow resistance values of models 2 and 3 are 1.2 and 1.5 times, respectively, that of model 1. The driving efficiency of model 1 is the highest among the three models. Pressure to the driver's face in models 2 and 3 is 1.2 times higher than in model 1. Because the pressure to the driver's face in model 1, with mounting gradient of $60^{\circ}$, is the lowest among the three models, model 1 is the safest. This result can be applied to improve the safety of motorcycle drivers.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.97-103
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• 2002

Vibration isolation technology using an air spring and laminated rubber bearing is widely used because it has excellent vibration isolation characteristics. In the part of that, we usually make use of the self-damped air suing. It is occupied two chambers, restrictor, diaphragm and load plate. Two chambers contain compressed air and the volume of chambers and the area of load plate give a definition of stiffness and load. The restrictor and the volume ratio of two chambers give a definition of damping ratio. The conventional model of restrictor is made of one orifice and it causes turbulent flow in the orifice at the region of large deflection. The stillness of air suing is larger and the damping is lower in the region of large deflection. In the multi-orifice case, the stiffness is similar to air spring with one orifice but damping ratio is larger than conventional air spring. And damping ratio is smaller than conventional air suing in small deflection region. Deflection is small in the region of high frequency so small damping is better than large damping. As a result, we can reduce the storage stiffness of air suing in the wide region of deflection and increase the damping ratio in the region of large deflection. After this, we will try to and the relation of Reynolds Number and Flow Resistance then we are going to make another restrictor for air spring to improve damping ratio and stiffness.

• Annals of Clinical Neurophysiology
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• v.8 no.1
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• pp.94-97
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• 2006

Bickerstaff's brainstem encephalitis (BBE) is a rare disorder with acute ophthalmoparesis, ataxia, consciousness disturbance, and pyramidal signs of suspected autoimmune origin. A-62-year-old woman developed acute diplopia, dysarthria, gaze-paretic nystagmus and gait ataxia. Her mental status fell subsequently into stupor. Brain MRI and nerve conduction study showed no significantly abnormal findings. Electroencephalography revealed diffuse low voltage slowings. After treating with intravenous immunoglobulin, she demonstrated rapid clinical recovery. This case suggests that immunoglobulin can be an alternative option in BBE treatment, especially when plasmapheresis and corticosteroids are difficult or contraindicated.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.4 s.152
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• pp.615-622
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• 2006

A tool to evaluate the subjective wearing comfort of caps from the objective measurement of pressure was developed. Comfortable Fittability Index(C.F.I) and Holding Power(HP) were defined to represent the subjective wearing comfort of caps. As a preliminary step to define the Comfortable Fittability Index(C.F.I), average pressure, pressure distribution, standard deviation of pressure were obtained and subjective sensation were evaluated by wearing caps. Also Holding Power(HP) was estimated from wind tunnel testing. Two sets of caps were evaluated, one set made of elastic fabric(F-caps) and the other set made of non-elastic fabric(S-caps). F-caps begin to be taken off by the higher wind velocity and thus exhibited higher values of Holding Power. On the other hand, F-caps exerted lower average pressure, narrower pressure distribution, smaller standard deviation.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.5
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• pp.148-155
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• 2011

This study analyzes stress, fatigue and vibration at clutch on the rotation of wheel. Eigenfrequencies from 1'st to 6'th order about clutch assembly are shown with the vibration at more than 800Hz. Maximum equivalent stress is shown with the frequency of 800Hz in case of the harmonic vibration applied with force. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. In case of 'Sample History' with the average stress of 0MPa to $-10^5$ MPa and the amplitude stress of 0MPa to $10^5$ MPa, the possibility of maximum damage becomes 3.23%. This stress state can be shown with 6 times more than the damage possibility of 'SAE bracket history' or 'SAE transmission'. The structural result of this study can be effectively utilized with the safe design of clutch.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.1
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• pp.80-86
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• 2009

Main bearing cap is one of the essential structural elements in internal combustion engine. Main bearing cap guides and holds the crankshaft, withstanding the full combustion and inertia loads of the engine. A seamless design methodology using FEA has been proposed to produce a reliable design of main bearing cap. A Levy's thick cylinder model was applied to calculate the contact pressure between bearing shell and housing bore. A calculated contact pressure at housing bore is within the allowed limit comparing with that from bearing shell model. An adequate FEA model was suggested to obtain reliable solutions for the durability of main bearing cap. 3D global model consists of engine bulkhead, main bearing cap, and bolts. Sub-model consisting of cap and part of bolts is used to get detailed solution of main bearing cap. A very careful contact modeling practice is needed to resolve the convergence problems frequently encountering during combined geometric and material non-linear problems. A proposed methodology has been applied to the main bearing cap model successfully and obtained reliable stress results and fatigue safety factors.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.5
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• pp.104-112
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• 2013

This study investigates the structural analysis result with vibration and fatigue on 3 kinds of bicycle saddle models. When the static load applies on the upper plane of model, maximum stress becomes within the allowable stress in case of model 1. As the value of Stress or deformation becomes lower on the order of model types 1, 2 and 3, these models become more stabilized or safer at durability in this order. On the vibration analysis, model type 1 has the maximum stress or deformation more than 5 times by comparing with model type 1 or 2. Model type 1 becomes most excellent on vibration durability. As maximum displacement due to vibration happens in case of model type 3, it becomes unstabilized. But the stresses of model types 1, 2 and 3 become within the allowable stress and these models are considered to be safe. At the status of the severest fatigue load, model type 3 becomes safer than model type 1 or 2. This study result is applied with the design of safe bicycle saddle and it can be useful to improve the durability by predicting prevention against the deformation due to its vibration and fatigue.

• Journal of Radiation Protection and Research
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• v.31 no.1
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• pp.9-15
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• 2006

A long-range atmospheric dispersion model named LADAS has been developed to understand the characteristics of the transport and diffusion of radioactive materials released into atmosphere. The developed numerical model for validation was compared with the results of the ETEX which is the long-range field tracer experiment. As a comparative study, the calculated concentration distributions agreed well in the case of the usage of the mixing heights calculated by the Richardson number than the usage of the constant mixing heights in LADAS model. Also, the calculated concentrations agreed with the time series of the measured ones at some sampling points.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.612-618
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• 2009

Recently the roles of railways about the prevention of global warming caused by greenhouse gases and for low carbon green growth are larger than ever. And the railroad-related research institutions have been active in researching for energy conservation. Especially the urban railroad has been emerged as the best means of transportation compared to the general public transportation systems in punctuality, stability, ecology and etc. In operating the urban railroad system there are various ways for energy savings. In the larger category, One is the hardware aspect according to the structure of the vehicle and the development of control systems. The other is the software aspect which efficient train operation can be made through control of driving patterns and driving diagram. In this paper, there is sense to analyze the result in verifying expectation relation with variable and the use of electric power on this after selecting main variables that can influence to the energy of the train operation in the software aspect. First, after collecting the basic data related to operation(train speed, operating hours, power consumption, the position of stopping station, electrical power system etc.) and according to this, investigating the consumption of the energy of the operation, in the side of energy consumption deducing and analyzing problem, this will be found solutions.