• Journal of KSNVE
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• v.11 no.3
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• pp.449-454
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• 2001

The shock performance of hard disk drives has been a serious issue for portable computers and AV application HDD. Focusing on the motion of an actuator, we investigated non-operational shock mechanism and studied several parameters that affect the shock performance by experimental analysis. It was found that there are two important factors fort the actuator to endure high shock revel. One is a shock transmissibility and the other is a beating between the arm blade and the suspension. To generalize the shock transmissibility, the concept of shock response spectrum was introduced. The shock response spectrum of the actuator system was obtained experimentally and compared with that of an analytical single degree of freedom model. It was found that there was a good agreement. The first bending natural frequency of the arm blade was found to be the most important factor for the low shock transmissibility. By applying the shock response spectrum and avoiding the beating, we could design an actuator of high shock performance.

• Journal of KSNVE
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• v.11 no.1
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• pp.141-146
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• 2001

This paper deals with an application of Magneto-Rheological (MR) fluid to a small size mount for precision equipment of automobiles. MR fluid is known as a class of functional fluids with controllable apparent viscosity of fluid by the applied magnetic field strength. A typical MR fluid is a suspension where pure iron particles of 1-20 (m in diameter are dispersed in a liquid such as mineral oil or silicone oil, at the concentration of 20 - 40 vol%. Electro magnetic coil is installed at the bottom of a variable-damping mount filled with MR fluid, and performance of the mount was investigated experimentally. Furthermore, the Properties of the MR Mount on experimental study were explained analytically by mechanical model of the MR mount.

• Journal of the Korean Society of Safety
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• v.17 no.1
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• pp.79-86
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• 2002

In the case of earthquake, it is necessary to install earthquake instruments and to measure the ground motions for stable gas supply and restoration in case of supply suspension. Because each point in the site of the gas facilities has different characteristics of ground motion, it is recommended to measure at the point where the ground motion is representative. In this paper, ground motion analysis and noise pattern analysis are carried out to select suitable point for the installation of earthquake instruments and to set of dynamic range of sensors.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1667-1673
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• 2015

The vibration and noise caused by the dynamic interaction between electromagnetic suspension and the linear synchronous motor stator beneath a flexible guideway remain problems in designing attractive Maglev trains. One possible method to reduce the sources of vibration is to minimize the detent force in the linear synchronous motor that creates variations in both lift force and thrust. This paper proposes lowering detent force by using separated core instead of single united core. The magnet is designed to adapt to the deflected guideway at a speed of 550km/h. This study will analyze the electromagnetic field and control performance, and how they relate to lift forces and dynamic responses.

• Journal of KSNVE
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• v.11 no.2
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• pp.265-275
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• 2001

This research has been performed to reveal the hysteresis phenomena of the hunting motion in a railway passenger cars. It is found that there are some factors and its operation region to make the nonlinear critical speed reacts to them more sensitively than the linear critical speed. The simulation results show that a self steering bogie system can be a substitute proposal to improve curving Performance together with the reduction of hysteresis of critical speed. Full scale roller rig test is carried out for the validation of the numerical results. Finally, it is certified that wear of wheel profile and stiffness discontinuities of wheelset suspension caused by deterioration have to be considered in the analysis to predict the hysteresis of critical speed precisely.

• Journal of the Korean Society for Railway
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• v.4 no.4
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• pp.123-130
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• 2001

A chevron rubber spring is used in primary suspension system for rail vehicle. The chevron spring support the load carried and reduces vibration and noise in operation of rail vehicle. The computer simulation using the nonlinear finite element analysis program MARC executed to predict and evaluate the load capacity and stiffness for the chevron spring. The appropriate shape and the material properties are proposed to adjust the required characteristics of chevron spring in the three modes of flexibility. Also, several samples of chevron spring are manufactured and experimented. It is shown that the predicted values agree well the results obtained from experiment.

• Journal of the Korean Society for Railway
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• v.8 no.2
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• pp.182-187
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• 2005

Air spring system was widely accepted for railway vehicle secondary suspension to reduce and absorb the vibration and noise. The low natural frequency ensures a comfortable ride and an invariably good stiffness. In this paper, the characteristics and durability test was conducted in laboratory by using servo-hydraulic fatigue testing system to reliability evaluation of air spring for electric railway vehicle. The experimental results show that the characteristics and durability of domestically developed productions are shown in good results. And to guarantee the adaption of air spring, the ride comfort and air pressure variation were measured in train test on subway line.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.83-89
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• 2005

Rubber spring is used in primary suspension system for railway vehicle. This rubber spring has function which reduce vibration and noise, support the load carried in operation of rail vehicle. The non-linear properties of rubber which are described as strain energy function are important parameter to design and evaluate of rubber components. These are determined by material tests which are tension, compression and shear test. The behaviors of load-displacement of rubber spring for rail vehicle are evaluated by using commercial FEA code. It is shown that the results by FEA simulations are in close agreement with the test results

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.468-475
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• 2000

An air spring was accepted for rail vehicle secondary suspension to reduce and absorb tile vibration and the noise. The air spring for the electric railway was developed with domestic technology, which consisted of a cord reinforced rubber bellows, a upper plate, a lower plate and a stopper rubber spring The fatigue test was conducted in laboratory by using servo hydraulic fatigue testing system to verify the durability. And to guarantee the adaptation of this air spring, the ride comfort and the air pressure variation were measured in train test on Boondang line.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.8
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• pp.773-778
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• 2009

Chevron rubber springs are used in primary suspensions for rail vehicle. Chevron rubber spring have function which reduce vibration and noise, support load carried in operation of rail vehicle. Prediction and evaluation of characteristics are very important in design procedure to assure the safety and reliability of the rubber spring. The computer simulation using the nonlinear finite element analysis program executed to predict and evaluate the load capacity and stiffness for the chevron spring. The non-linear properties of rubber which are described as strain energy functions are important parameters. These are determined by material tests which are uniaxial tension, equi-biaxial tension and shear test. The appropriate shape and material properties are proposed to adjust the required characteristics of rubber springs in the three modes of flexibility.