• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1784-1789
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• 2000

Recently "ride comfort" problem becomes increasingly important because of today's needs for train speedup. The concept of term "ride comfort" is equivocal. Generally it is defined as the vehicle vibration. There are many studies on evaluation method of ride comfort for railway. But each of them recommends the different assessment method and the different guidance. So users must review whether they can apply it to their system or not. In general, the evaluation methods defined in the standards - ISO 2631, UIC 513 R, and Ride Index suggested by Sperling - have been used in the railroad. We performed the ride comfort test in KNR line(Seoul - Kwangju) and simulated the relationship between them. And we compared our results to ERRI's.

• Proceedings of the KSR Conference
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• 한국철도학회 1999년도 춘계학술대회 논문집
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• pp.159-166
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• 1999

In this paper, running performance analyses of an articulated light rail vehicle are carried out using VAMPIRE software package. The stability analysis to determine the critical speed and the safety analysis such as derailment coefficients, lateral forces of wheels and reduction of wheel load are carried for the track conditions of straight, transition and curving range to the operating velocity of 40km/h. Also, ride quality is analyzed. As the results of analysis, the safety of light rail vehicle satisfied with the limit values and the ride quality for tare and full load condition was shown to the "not uncomfortable" level in ISO 2631-1 (1997) criteria.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• 제12권8호
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• pp.626-631
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• 2002

A modified equation for the evaluation of discomfort of a seated human body exposed to differential vibration at the seat and the floor was proposed in this paper. Through the review and analysis of the preceding studies, effect of phase difference between the seat and the floor vibration on discomfort were quantitatively identified. The phase effect was shown to be governed by not only phase difference between the two vibrations but both their frequency and the magnitude, which means the present equation for the evaluation of perceptual amount of vibration provided by ISO 2631-1 should be modified. The proposed equation was developed such that the correction function was multiplied to the present equation. The correction function consisted of three parts, each of them represented the effect by phase difference, frequency and vibration magnitude on discomfort respectively.

• Journal of Korean Association for Spatial Structures
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• 제17권2호
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• pp.71-77
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• 2017

In this study, the boundary non-linear analysis of the sky bridge subjected to walking load and running load is performed. The sky bridge is installed in the mid-story between two buildings and the walking load and running load induced by pedestrians are measured by load cell. LRB is modeled as a non-linear hysteresis model to accurately represent the behavior of LRB. For the serviceability evaluation of sky bridge, the acceleration responses of sky bridge are analyzed based on ISO 2631-2 and the velocity response are analyzed based on standards Bachmann &Amann. In serviceability evaluation of this sky bridge, the pedestrian can not perceive the vibration except for resonance running loads consequently. Therefore, it is concluded that this sky bridge haven't problem in the serviceability.

• Transactions of the Korean Society of Automotive Engineers
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• 제3권5호
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• pp.100-110
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• 1995

The human subject perception response according to vertical vibration and pitching was analyzed with a five degree of freedom model. The vehicle dynamic system with the delayed colored noise excitation and the passenger perception response was arranged as an integrated viration system and could be analyzed simultaneously for seven different combination of vehicle suspension. ISO2631 and BS6841 was adapted for analyzing the passenger perception reponse. Simulation results shows that passenger feel relatively less discomfort due to pitching compared to vertical vibration and road type was not necessary to be considered as a design parameter in view of comfort analysis.

• Proceedings of the KSR Conference
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.3226-3236
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• 2011

In this paper, with the background features on which measuring the transverse left-right and up -down vibration of wheel, bogie and body by wireless measurement system, performance evaluation systems which can assess the running behavior of high speed trains based on UIC code 518-OR and evaluate the ride comfort of them based on ISO code 2631 and UIC code 513 were developed. The characteristics of dynamic vibration are generally analyzed by an acceleration of a car body of high speed train and the acceleration can be applied to evaluation of running safety. In this paper, also matching system of distance from tachometer and vibration from accelerometer was programmed in development software, and the SD card embedded system which prevent to loss of data in wireless measurement was mounted on this system. Finally the software perform to analysis with filtering and statistical post-process in the unit sections and zones and focus on developing the capability monitoring in the main control center. For the verification of this system, the running behavior and safety factor were analyzed based on field measured data of the Cheonjun-gunnum-sun turn out point in the new KTX railway.

• Journal of KSNVE
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• 제11권3호
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• pp.461-470
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• 2001

A friction-type clutch system sometimes generates spick-slip vibration during engagement, which disturbs smooth start of a car and makes a passenger uncomfortable. In this study, the spick-slip vibration in four types of friction couples was investigated at two different engagement conditions respectively of which the amount of slip time and clutch travel was varied. Results are found as follows. First, the vibration increased at the condition of small engine torque and large torque fluctuations due to higher harmonics of engine speed. Second, the friction couple without a pre-damper has advantages of reducing the vibration. This study also suggested an evaluation method of vehicle vibration in the view point of human perception by using the frequency weighting of ISO2631-1.

• Journal of Sensor Science and Technology
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• 제13권5호
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• pp.369-377
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• 2004

Recently, the "ride comfort" problem becomes increasingly important because of today's needs for train speedup. The concept of term "ride comfort" is equivocal. Generally it is defined as the vehicle vibration. There are many studies on evaluation method of ride comfort for railway. But each of them recommends the different assessment method and the different guidance. In general, the evaluation methods defined in the standards, such as ISO 2631 and UIC 513R, and Ride Index suggested by Sperling, have been used in the railroad. But, only one or two methods of these can be evaluated by using the commercial ride comfort measuring system. Therefore, it is necessary to develop the new ride comfort measuring system for railway with multi-function. In this paper, the generalization of "ride comfort" and the design and verification of new ride comfort measuring system for railway with multi-function have been described and the application examples has been introduced.

• Advances in Automotive Engineering
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• 제1권1호
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• pp.1-20
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• 2018

The aim of this study is the optimization of the parameters of interconnected Hydro-Pneumatic (HP) suspension system of a three-axle vehicle for ride comfort and handling. For HP suspension systems of equivalent vertical stiffness and damping characteristics, interconnected HP suspension systems increase roll and pitch stiffness and damping characteristics of the vehicle as compared to unconnected HP suspension systems. Thus, they result in improved handling and braking/acceleration performances of the vehicle. However, increased roll and pitch stiffness and damping characteristics also increase roll and pitch accelerations, which in turn result in degraded ride comfort performance. Therefore, in order to improve both ride comfort and vehicle handling performances simultaneously, an optimum parameter set of an interconnected HP suspension system is obtained through an optimization procedure. The objective function is formed as the sum of the weighted vertical accelerations according to ISO 2631. The roll angle, one of the important measures of vehicle handling and driving safety, is imposed as a constraint in the optimization study. Upper and lower parameter bounds are used in the optimization in order to get a physically realizable parameter set. Optimization procedure is implemented for a three-axle vehicle with unconnected and interconnected suspension systems separately. Optimization results show that interconnected HP suspension system results in improvements in both ride comfort and vehicle handling performance, as compared to the unconnected suspension system. As a result, interconnected HP suspension systems present a solution to the conflict between ride comfort and vehicle handling which is present in unconnected suspension systems.

• Wind and Structures
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• 제31권5호
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• pp.393-402
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• 2020

Long-span bridges with high flexibility and low structural damping are very susceptible to the vortex-induced vibration (VIV), which causes extremely negative impacts on the ride comfort of vehicles running on the bridges. To assess the ride comfort of vehicles running on the long-span bridges subjected to VIV, a coupled wind-vehicle-bridge system applicable to the VIV case is firstly developed in this paper. In this system, the equations of motion of the vehicles and the bridge subjected to VIV are established and coupled through the vehicle-bridge interaction. Based on the dynamic responses of the vehicles obtained by solving the coupled system, the ride comfort of the vehicles can be evaluated using the method given in ISO 2631-1. At last, the proposed framework is applied to several case studies, where a long-span suspension bridge and two types of vehicles are taken into account. The effects of vehicle speed, vehicle type, road roughness and vehicle number on the ride comfort are investigated.