• Proceedings of the KSR Conference
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• 2007.05a
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• pp.698-704
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• 2007

Articulated vehicles which have a pivoting joint allowing the vehicle to rotate more easily are difficult to turn the curves because of their long length. In order to review operational safety, turning characteristics related to geometric design should be investigated when articulated vehicles run on the road which can be interfered with other vehicles. The vehicles to review the turning characteristics are the normal articulated bus in Seoul with FWS(front wheel steering) and new bimodal tram with AWS(all wheel steering). Steering characteristics and geometric design were investigated such as turning radius, offtracking, swept path width and swingout. The results were reviewed with respect to the standards of vehicle safety and road design.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.583-589
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• 2010

This paper describes the design process and the test of split wheel-mounted brake discs for high speed train with maximum speed 180km/h. A disc set composed 2 disc rings and individual rings are partitioned into 3 pieces with the same circumferential angle. Because partitioned disc rigs are exposed to severe centrifugal force as the vehicle speed increase, finite element analyses used in the design process to ensure mechanical safety. A prototype was verified its mechanical safety through the spin test up to 250km/h. 2 prototypes for 1 wheelset are mounted to Korean Tilting Train(TTX) and have been running over 15,000km

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.411-412
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• 2006

It is very difficult to analyze the dynamic characteristic because railway vehicle is a very complex system which are connected various mass element with railway vehicle system. To realize and analyze actual phenomenon has restriction that usual commercial software calculates creep force under creep theory about wheel-rail contact mechanism as basic analyzing, and approach about contact point are based on two dimensional non-linear contact theory and simplified Hertzian contact which considers just displacement change on the YZ plain. Therefore, to solve these problems there should be a new approach difference with existing one. In this research, a new algorithm for finding wheel-rail contact position, calculation method of contact force and applied force will be presented.

• Tribology and Lubricants
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• v.23 no.5
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• pp.228-233
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• 2007

This paper presents the case studies on the friction related wears of an automotive tire, which is strongly connected to the safety and comfort of a driver during a running of a car. Wear scars of a tire tread are affected by various causes such as an air pressure, a wheel alignment, a driving speed, road conditions, starting and braking habits of a driver. The data were collected from used tires for a replacement at the car service center. Most of the wear problems came from the improper repair and adjustment of revolving components, which cause an unbalanced wear of a tread part of a tire. Thus, the regular checking of a tire radically reduces the wear scars of a tire and may increase a driving safety and a fuel economy of a car and a wear life of a tire.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.849-854
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• 2008

For the running safety assessment of Saemaul train passing through curves, an analysis model for multibody system has been developed. By using this model and ADAMS/Rail, sensitivity analyses depending on the variation of parameters related to the derailment coefficients have been conducted. According to the increase of running speed, the derailment coefficient and unload ratio were increased. At high speed, the derailment coefficient and unload ratio of left wheel showed higher than right wheel. If the cant increased, the derailment coefficient and unload ratio increased. but decreased based on the balance cant value by the curvature and running speed.

• Proceedings of the KSR Conference
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• 2002.10b
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• pp.898-903
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• 2002

The railroad is a means of large transportation which has many talents such as a safety and a regularity. That is a results from various confidential performance tests and evaluations of the system. The railroad system consist of various subsystems - vehicle, power supply, signal, communications, track structures, operations, etc. Among them, as an item of safety evaluation there is a measurement of wheel/rail force, so called a measurement of derailment coefficient. This is a very important item because a derailment of a train will bring about a big accident. Especially it is more inportant in high speed rail of which operation speed is over two times as fast as existing rail. In this paper, it is introduced to preprocess the wheelset for measuring wheel/rail force of high speed rail, such as to treat a measuring wheelset, its finite element analysis, adhesion of strain gauges and static load test.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.421-428
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• 1998

Sensitivity analysis of suspension elements of an articulated bogie for light railway vehicles is presented. The ride, stability and safety are used as dynamic performance index. Suspension elements of 10 and a conicity of wheel are used as design variables, To analyze sensitivity of design variables, the railway vehicle dynamics analysis program AGEM is used. The results shows that the secondary suspension elements have a strong effect on ride and the primary suspension elements have a moderate effect on ride. Conicity of wheel has a strong effect on the stability, The safety is not effected by all the design variables.

• Journal of the Korean Society of Safety
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• v.38 no.4
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• pp.1-7
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• 2023

The steel wheels of urban railway vehicles gather a lot of data through regular measurements during maintenance. However, limited research has been carried out utilizing this data, resulting in difficulties predicting the maintenance period. This paper studied a machine learning model suitable for mileage prediction by studying the characteristics of mileage change according to diameter and flange thickness changes. The results of this study indicate that the larger the diameter, the longer the travel distance, and the longest flange thickness is at 30 mm, which gradually shortened at other times. As a result of research on the machine learning prediction model, it was confirmed that the random forest model is the optimal model with a high coefficient of determination and a low root mean square error.

• Journal of the Korean Society of Safety
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• v.27 no.2
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• pp.84-91
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• 2012

This study evaluated three forces (lifting, pushing and twisting) required to maneuver the single-wheel barrows according to handle height, width, horizontal angle and vertical angle. The four independent variables were varied in two levels. Handle height was varies in two levels : 'knuckle height (KH)' and 'KH + 0.1 ${\times}$ stature'. The two handle widths were '1.5 ${\times}$ shoulder width (SW)' and '1.75 ${\times}$ SW'. Two angles of $0^{\circ}$ and $15^{\circ}$ were used for horizontal and vertical angles. The 24 factorial design was used in the experiment. Twelve healthy male students (undergraduate and graduate) participated in the experiment. Subjects exerted three forces (pushing, lifting, and twisting clockwise) in each experimental condition. The order of 16 treatment conditions was determined randomly. Results showed that the effects of the four factors were different according to three forces. While lifting and twisting forces were higher in 'knuckle height', the pushing force was higher in 'KH + 0.1 ${\times}$ stature' (p < 0.05). Lifting and pushing forces showed higher values in the horizontal angle $0^{\circ}$ than in $15^{\circ}$. Handle width and vertical angle showed no statistically significant main effects on three forces (p > 0.05). Results of this study could be used as basic data for the ergonomic design of handle variables of one- or two-wheel barrows.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.2 s.29
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• pp.161-167
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• 2007

The goal of this paper is to develop the speech recognition system which can control the ship's auto pilot. The feature parameters predicting the speaker's intention was extracted from the sample wheel orders written in SMCP(IMO Standard Marine Communication Phrases). And we designed the post-recognition procedure based on the parameters which could make a final decision from the list of candidate words. To evaluate the effectiveness of these parameters and the procedure, the basic experiment was conducted with total 525 wheel orders. From the experimental results, the proposed pattern recognition procedure has enhanced about 42.3% over the pre-recognition procedure.