• Proceedings of the KSR Conference
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• 2007.05a
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• pp.686-691
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• 2007

The ride comfort is more important according to train speedup. Generally it is defined as the vehicle vibration. There are many studies on evaluation method of ride comfort for railway. In the case of Korean high speed train(HSR 350x), the ride comfort has been assessed by statistical method according to UIC 513R. To verify the design requirements for the performance of HSR 350x, the qualification tests had been conducted from August 19, 2002 to December 2004 and the stabilization and reliability tests are carried out nowadays. Up to December 2006, total test runs and the accumulated milage of the train were 357 times and 164,000km, respectively. A total of 352 ride indices had been acquired through the on-line test from Aug. 2002 to Dec. 2006. In this paper, we have reviewed the characteristics of ride comfort for HSR 350x according to the operational conditions, such as load and track conditions, season and used time, by using the tests data.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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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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• 1998.11a
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• pp.405-412
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• 1998

Recently“ride comfort”problem becomes increasingly important because of today's needs for train speedup The concept of term “riding 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 then recommends the different assessment method and the different guidance. So users must review whether they can apply it to their system or not. In this paper, we discuss the evaluation methods defined in the standards - ISO 2631, UIC 513 R, CEN DRAFT prENV 12299 and the ride index suggested by Sperling.

• Journal of the Korean Society for Railway
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• v.6 no.2
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• pp.114-121
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• 2003

In this paper, a new evaluation system was developed for ride comfort test and vibration level test on railway vehicles. These tests are carried out by applying different equipments and test procedures before now. But this developed system is capable of ride comfort test and vibration test by a single integrated system. Also, the evaluation algorithm for the ride comfort was compared and verified by simulation results with VAMPIRE software. With this developed system, the comfort in a passenger coach and the vibration in a freight car were verified by the results in field test.

• Journal of Sensor Science and Technology
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• v.14 no.3
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• pp.144-149
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• 2005

In this paper, we introduce the variation of ride characteristics for HSR 350x(Korea High Speed Train project) through on-line test during about 3 years. The concept of term "ride comfort" is equivocal. Generally it is evaluated as the vehicle vibration. The ride comfort for HSR 350x has been assessed by statistical method according to UIC 513R. The testing results show that HSR 350x has no problems from the viewpoint of the comfort ride on the high speed line and conventional line and that 1st and 2nd suspensions play an important role in the ride characteristics for high speed train.

• International Journal of Automotive Technology
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• v.7 no.3
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• pp.309-314
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• 2006

In this paper, the ride comfort from a computer simulation was compared to the experimental result. For measuring ride comfort of a passenger car, acceleration data was obtained from the floor and seat during highway running with different speeds. The measured acceleration components were multiplied by the proper weighting functions, and then summed together to calculate overall ride values. Testing several passenger cars, the ride comforts were compared. In order to investigate the effect of vibration signals on the steering wheel, an apparatus to measure the vibrations and weighting functions on the steering wheel were designed. The effect of the steering accelerations on the ride comfort were investigated and added for the overall ride comfort. For the computer simulations, Korean dummy models were developed based on the Hybrid III dummy models. For the Korean dummy scaling, the national anthropometric survey of Korean people was used. In order to compare and check the validity of the developed Korean dummy models, dynamic responses were compared to those of Hybrid III dummy models. The computer simulation using the MADYMO software was also compared to the experimental results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.959-960
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• 2012

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1000-1005
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• 2010

Ride comfort is an important factor for the development of a high-speed train. The aerodynamic force to a high speed train inside tunnels increases the car-body vibration and makes its ride comfort worse. In this study, the aerodynamic force is estimated through a CFD analysis using ADINA, and its car-body vibration and ride comfort are calculated for the aerodynamic force which acts on the side of the train. The numerical results show that the vibration is a lateral mode of the car-body and decreases the ride comfort. On the basis of this numerical simulation, more accurate simulation is necessary for the shape of tunnel and the lateral suspension system of a high speed train.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.268-273
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• 2006

The ride comfort is more important in the train speedup. Generally, it is defined as the vehicle vibration. There are many studies on evaluation method of ride comfort for railway. But the ride comfort for Korean high speed train(HSR 350x) has been assessed by statistical method according to UIC 513R. It is very difficult for HSR 350x to run at constant speeds above 310 km/h during 5 minutes required in UIC 513R because of the same operational condition as KTX and the infrastructures. In this paper, the ride index at high speed above 310 km/h has been predicted by using those obtained below 310 km/h and the comfort for HSR 350x has been reviewed in these speeds.

• Smart Structures and Systems
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• v.24 no.1
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• pp.141-155
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• 2019

This work evaluates the influence of negative stiffness on the performances of various vehicle suspension systems, and proposes a re-centering negative stiffness device (NSD). The re-centering NSD consists of a passive magnetic negative stiffness spring and a positioning shaft with a re-centering function. The former produces negative stiffness control forces, and the latter prevents the amplification of static spring deflection. The numerical simulations reveal that negative stiffness can improve the ride comfort of a vehicle without affecting its road holding abilities for either passive or semi-active suspension systems. In general, the improvement degree of ride comfort increases as negative stiffness increases. For passive suspension system, negative stiffness brings in negative stiffness feature in the control forces, which is helpful for the ride comfort of a vehicle. For semi-active suspensions, negative stiffness can alleviate the impact of clipped damping in semi-active dampers, and thus the ride comfort of a vehicle can be improved.