• Journal of the Korean Society for Railway
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• v.10 no.4
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• pp.17-25
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• 2007

• The tire
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• s.90
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• pp.2-8
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• 1980

앞으로의 자동차용 타이어 개발방향은 타이어의 Pattern을 변경하거나 또는 승차감을 향상시키는 것도 중요하지만 회전저항이 작은 타이어를 개발하여 에너지를 절약하여야 된다는 것이 더욱 중요한 과제이다.

• Proceedings of the ESK Conference
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• 2004.10a
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• pp.30-30
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• 2004

• Railway Journal
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• v.16 no.4
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• pp.37-46
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• 2013

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.12
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• pp.1199-1205
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• 2011

In the present work, a seat suspension system adopting semi-active damper is evaluated for driver's ride quality. A cylindrical type of ER(electrorheological) damper is designed and manufactured for the seat suspension of heavy vehicles. The governing equation is derived under consideration of human vibration. A sliding mode controller is then synthesized and experimentally realized on the manufactured ER seat suspension while a driver is sitting on the controlled seat. Ride quality is evaluated by fatigue decreased proficiency boundary, vibration dose value and crest factor utilizing weighted-acceleration according to ISO2631.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.6
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• pp.229-235
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• 1996

The tapered leaf spring is regarded as the adequate tool to improve ride quality and to reduce vehicle weight of commercial vehicles. These effects are due to minimizing the contact area of each leaf by reducing the number of leaves and by optimizing the thickness profile of each leaf. But in adapting the tapered leaf spring to improve ride quality, we often have some problems of bad pitching and bouncing motion. This paper shows the basic properties of tapered leaf spring by rig tests and how to improve ride quality of a vehicle with tapered leaf springs, compared with multi-leaf spring. From the results of vehicle tests and rig tests it is concluded that the ride quality was effected by the dynamic spring rate and the friction of the tapered leaf spring.

• Journal of KSNVE
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• v.10 no.2
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• pp.269-279
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• 2000

This paper deals with the development of biomechanical model on a seat with backrest support in the vertical direction. Four kinds of biomechanical models are discussed to depict human motion. One DOF model mainly describes z-axis motion of hip, two and three DOF models describe z-axis of hip and head, and while nine DOF model suggested in this study represents more motion than the otehr model. Three kinds of experiments were executed to validate these models. The first one was to measure the acceleration of the floor and hip surface in z-axis, the back surface in x-axis, and the head in z-axis under exciter. From this measurement, the transmissiblities of each subject were obtained. The second one was the measurement of the joint position by the device having pointer and the measurement of contact position between the human body and the seat by body pressure distribution. The third one was the measurement of the seat and back cushion by dummy. The biomechanical model parameters were obtained by matching the simulated to the experimental transmissiblities at the hip, back, and head.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.365-368
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• 2005

The dynamic model was developed to analyze vibration acceleration and ride comfort during the operation of rubber-tired light rail vehicles. The ride comfort for standing passengers was analyzed in accordance with ISO 2631-1, UIC 513R, and CEN Draft prENV 12299 using this model. The result was applied to the detail design of Korean-standard, rubber-tired light rail vehicles, and the detail specifications related to ride comfort was determined based on this result. The ride comfort test was performed along the test track by using 2 car-train, and its result was compared with that of the ride comfort analysis, verifying the validity of the developed dynamic model. It was also verified whether or not the developed Korean-standardized, rubber-tired light rail vehicle met specified target specifications on ride comfort.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.6
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• pp.135-142
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• 2000

In this paper, 3-dimensional numerical model of an escalator is developed to study the vibration characteristics. This proposed model is able to consider the elastic deformation of the frame during transient dynamic analysis. Deformation modes which are used to calculate the elastic deformation are selected from the FE model analysis. Because low frequency vibration is very important to the ride quality of fore/aft direction, low frequency deformation modes of the frame below 20Hz are considered. To show validity of this dynamics model, longitudinal acceleration of a step is compared with test data in frequency domain. Then robust design technique is applied to determine important design factors and improve ride quality with small number of experiments.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.7
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• pp.549-555
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• 2008

Analytical method to analyze the tolerance effect on the vehicle ride comfort is suggested in this paper. Ride comfort is one of the most important performance indices which decide the vehicle design quality. In general, the ride comfort is affected by the variations of parameters of a vehicle model. Therefore, the effects of the parameters on the ride comfort need to be evaluated statistically based on the whole-body vibration of the vehicle. In this paper, weighted RMS values of the acceleration PSD of a seat position are used to define the ride comfort. The equations of motion and the sensitivity equations are derived based on a 5-DOF vehicle model. By employing the sensitivity information of the acceleration at the seat position, the tolerance effect on the vehicle ride comfort could be effectively analyzed.