• Steel and Composite Structures
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• v.38 no.3
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• pp.271-280
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• 2021

In this study, the fatigue property of U rib-to-crossbeam connections in orthotropic steel bridge (OSB) crossbeams under heavy traffic vehicle load was investigated considering the effects of in-plane shear stress. The applicability of an improved structural stress (ISS) method was validated for the fatigue behavior analysis of nonwelded arc-shaped cutout regions in multiaxial stress states. Various types of fatigue testing specimens were compared for investigating the equivalent structural stress, fatigue crack initiation positions, and failure modes with the unified standards. Furthermore, the implications of OSB crossbeams and specified loading cases are discussed with respect to the improved method. The ISS method is proven to be applicable for analyzing the fatigue property of nonwelded arc-shaped cutout regions in OSB crossbeams. The used method is essential for gaining a reliable prediction of the most likely failure modes under a specific heavy traffic vehicle load. The evaluated results using the used method are proven to be accurate with a slighter standard deviation. We obtained the trend of equivalent structural stress in arc-shaped cutout regions and validated the crack initiation positions and propagation directions by comparing them with the fatigue testing results. The implications of crossbeam spans on fatigue property are less significant than the effects of crossbeams.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.69.4-69
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• 2001

In this paper, we developed a Windows 98 version of off-line programming system which can simulate a track vehicle model in 3D graphics space. The track vehicle was adopted as an objective model. The interface between users and the off-line program system in the Windows 98´s graphic user interface environment was also studied. The developing language is Microsoft Visual C++. Graphic libraries, OpenGL, by Silicon Graphics, Inc. were utilized for 3D Graphics.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.3
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• pp.79-84
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• 2007

Recently it is strongly required to develop the better fuel economy as well as basic power performance based on strict emission legislation. This paper focuses on studies of the engine cooling and ancillaries system among fuel economy factors in the developing stage. Firstly through the analysis of the current specifications, it is assessed whether each components may be designed properly, not overdesigned. Secondly, it is predicted how the fuel economy of each components can be improved. Finally the results are confirmed by vehicle field test equppted with the updatedcomponents. This study found good agreementbetween the prediction and the field test on the vehicle fuel economy improvements of the heavy duty engine vehicle with updated components such as engine cooling and ancilliaries.

• Journal of the Korean Society of Visualization
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• v.21 no.2
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• pp.8-13
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• 2023

The primary challenge in improving fuel efficiency and reducing air pollution for commercial vehicles is reducing their aerodynamic drag. Various flow control devices, such as cab-roof fairing, gap fairing, cab extender, and side skirt have been introduced to reduce drag, however, the drag reduction effect and applicability are different depending on each commercial vehicle model. To evaluate the fuel consumption of heavy vehicles, a comprehensive research approach, including drag force measurement, flow field analysis is required. This study investigated the effect of a cab extender, which installed rear region of cab, on a drag coefficient of commercial vehicle through wind tunnel experiments and CFD. The results showed that the cab extender significantly modified the flow structure around the vehicle, leading to 8.2% reduction in drag coefficient compared to the original vehicle model. These results would provide practical application for enhancing the aerodynamic performance and fuel efficiency of heavy vehicle.

• ETRI Journal
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• v.38 no.4
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• pp.787-797
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• 2016

Mining, construction, and other special vehicles for heavy use are designed to work under high-performance and off-road working conditions. The driving and executive mechanisms of the support structures and superstructures of these vehicles frequently operate under high loads. Such high loads place the equipment under constant risk of an accident and can jeopardize the dynamic stability of the machinery. An experimental investigation was conducted on a refuse collection vehicle. The aim of this research was to determine the working conditions of a real vehicle: the kinematics of the waste container, that is, a hydraulic rotate drum for waste collection; the dynamics of the load manipulator (superstructure); the vibrations of the vehicle mass; and the strain (stress) of the elements responsible for the supporting structure. For an examination of the force (weight) on the rear axle of a heavy vehicle, caused by its own weight and additional load, a universal measurement system is proposed. As a result of this investigation, we propose an alternative system for continuous vehicle weighing during waste collection while in motion, that is, an on-board weighing system, and provide suggestions for measuring equipment designs.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.318-319
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• 2011

Many countries are concentrating on the development of electric vehicle technology with increasing concerns about the global environment. Along with these concerns, plug-in hybrid electric vehicles(PHEVs) are being developed as environment-friendly cars which reduce greenhouse gas emissions and also eliminate the problem of range anxiety associated to all-electric vehicles, because the combustion engine works as a backup when the batteries are depleted. In this paper, electric equipments of the PHEV which meet the target specifications were developed, and their performance was proven through confirmatory testing on the PHEV at Korea Automotive Technology Institute(KATECH).

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.593-597
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• 2002

The power conversion system for Fuel Cell Electric Vehicle(FCEV), technical trend, and a various type of Fuel Cell and its characteristics are presented. Especially, this paper is focused on the control methods of power conversion devices applied for the Fuel Cell Electric Vehicle, configuration of power system and operation mode of the bidirectional DC/DC converter. The prevalent topology for the power conversion systems, simulation results and development a tendency of FCEV and it's market investigations are introduced.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.271-276
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• 1998

To apply the wear resistant steel plate for heavy duty vehicle, the wear characterisms of various kinds of commercial steel plates were invesigated by dry sand/rubber wheel tester which was tested under scratch abrasion mode. The wear tested pnaterials were boron steels which were manufactured by thereto machanical control process (TMCP) in order to achieve higher hardness. As the result of the test, wear resistance of steel plate increases with the hardness and carbon content. The wear loss of wear resistance steel plate (Hv440) is a half times than tinat of SWS490A (Hv160) steel plate in dry sand-rubber wheel test and the result in field test is similar to this dry sand/rubber wheel test result. Therefore, dry sand/rubber wheel tester can be used to predict the scratch abrasion life of the parts for heavy duty vehicle.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.67.4-67
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• 2002

Antilock brake System (ABS) is a essential safety equipment for modern vehicles. It prevents wheels from being locked-up when emergency braking of a vehicle is required. So it can improves directional stability of the vehicle, shortens stopping distance. Heavy Vehicles such as trucks and buses use mainly pneumatic pressures for their braking systems, where pneumatic modulators control the flow rate of compressed air thus braking pressures in the wheels. In this paper, a antilock braking algorithm which is suitable for heavy vehicles was developed. This algorithm uses limit cycle of wheels and is implemented in the ABS ECU. The developed algorithm and ECU were tested in the labo..

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.6
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• pp.135-141
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• 2005

Currently many safety assessment tests are conducted by crashing a vehicle against a rigid or deformable barrier. It is quite rational to evaluate crash performance of a vehicle in a barrier test in terms of vehicle stiffness and strength. However, there has been a lot of debate on whether barrier testing is a duplicate of real world crash collisions. One of the issues is car to car compatability. There are two essential subjects in compatability. One is partner-protection when crashing into another vehicle and the other is self-protection when struck by another vehicle. When considering a car to car frontal crash between a mini car and a large heavy car, it is necessary to evaluate human body stiffness of each vehicle. In this study, in order to evaluate the compatability of cars in car-to-car crashes, four tests were conducted. Test speed of each car is 48.3km/h, and the overlap of the mini and large car is $40\%$, and the overlap of the small cars is $100\%$. In all tests, only a drive dummy is used. The test results of the car to car crash test show that vehicle safety standard of mini car is not satisfied compared with large heavy car and HIC value of mini car is higher than large car. In this case observed that the relatively lower stiffness and weight of the mini car resulted in absorbing a large share of the total input energy of the system when crashed into the large heavy car.