• 한국군사과학기술학회지
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• 제12권3호
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• pp.266-271
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• 2009

Electronic equipments and a missile carried by heavy trucks are often subjected to vibration and shock excitation during their transportation. Electronic equipments are so vulnerable to vibration and shock input that it is necessary to know in advance the vibration level of the truck which cause the damage of equipments. Road tests of a heavy truck carrying a canister on different road conditions such as paved road, unpaved road, and washboard are performed and the effect of road conditions on the vibration characteristics are analyzed. Vibration levels were measured at various locations of the truck along the path through which vibration was transmitted. This study reveals that the velocity of the truck as well as the road surface conditions are main factors which affect the vibration levels of the truck. The power spectrum density of the measured vibration signal and the factors affecting the PSD are also analyzed in this paper.

• 대한기계학회논문집A
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• 제29권2호
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• pp.270-276
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• 2005

This paper develops the flexible computational model of a heavy truck by interfacing the frame modeled as a flexible body to the heavy truck's computational model composed of rigid bodies. The frame is modeled by the finite element method. Three torsional modes and three bending modes of the frame are considered for the interface of the heavy truck's computational model. The actual vehicle test is conducted off road with a velocity of 20km/h. The vertical accelerations at the cab and front axle are measured in the test. For the verification of the developed computational model, the measured vertical acceleration profiles are compared with the simulation results of the heavy truck's flexible computational model. E grade irregular road profile of ISO is used as an excitation input in the simulation. The verified flexible computational model is used to compare the vibration characteristics of a front suspension system having a multi-leaf spring and that having a tapered leaf spring. The comparison results show that the front suspension having a tapered leaf spring has a higher vertical acceleration at the front axle but a lower vertical acceleration at the cab than the suspension system having a multi-leaf spring.

• 한국자동차공학회논문집
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• 제16권4호
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• pp.128-134
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• 2008

In this paper, a hydropneumatic modeling and analysis of a heavy truck cabin air suspension system is presented. Cabin air suspension system is a system which improves ride comfort of a heavy truck and it can reduce vibration between truck frame and cabin. The components of the system, air spring, shock absorber, leveling valve and full cabin system are mathematically modelled using AMESim software. Simulation results of components and full cabin system are compared with experimental data of components and test results of a cabin using 6 axis simulation table. It is found that the simulation results are in good agreements with test results, and the hydropneumatic model can be used well to predict dynamic characteric of heavy truck cabin air suspension system.

• 제어로봇시스템학회논문지
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• 제5권4호
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• pp.496-503
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• 1999

In this paper, the improvement of cap tilting system in heavy truck and the development of program for automatic design are discussed. Cab tilting system takes some important roles in heavy truck, absorbing discomfort vibration from load, increasing repair efficiency and making sure of safety. Common manual cab tilting system cannot be easily tilt up in sloped road, giving difficulty to driver as cal tilting up/down. So recently hydraulic cab tilting system is in wide use. But some problem such as tilting up/down speed is not constant and sudden swing of cab has brought discredit from user. Therefore, this paper presents advanced cab tilting system which prevents sudden swing of cab and development of program for selecting design parameters automatically.

• 한국자동차공학회논문집
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• 제19권2호
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• pp.57-65
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• 2011

In this paper, a hydropneumatic modeling and dynamic analysis of a heavy truck semi-active cabin air suspension system is presented. Semi-active cabin air suspension system improves driver's ride comfort by controlling the damping characteristics in accordance with driving situation. So it can reduce vibration between truck frame and cabin. Semi-active cabin air suspension system is consist of air spring, leveling valve and CDC shock absorber, and full cabin system are mathematically modelled using AMESim software. Simulation results of components and full cabin system are compared with experimental data of components and test results of a cabin using 6 axis simulation table. It is found that the simulation results are in good agreements with test results, and the hydropneumatic model can be used well to predict dynamic characterics of heavy truck semi-active cabin air suspension system.

• 대한교통학회지
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• 제31권5호
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• pp.60-70
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• 2013

본 연구는 신호 교차로에서 대형 화물차의 정지로 인해 야기되는 온실가스 배출과 교차로 효율 저하를 완화하기 위해 좌회전 현시의 대형 화물차 대상 우선신호 알고리즘을 제안하고 효과를 분석한다. 대형 화물차의 진입 속도와 좌회전 속도를 고려한 녹색신호 연장 기법을 적용하며, 우선신호 제공으로 인해 발생할 수 있는 일반차량의 지체 증가를 완화하기 위해 두 가지 보상 전략을 수립하여 비교한다. 제안된 알고리즘의 효과를 분석하기 위해 PARAMICS를 이용한 시뮬레이션 분석을 수행하며 Comprehensive Modal Emissions Model (CMEM)을 이용하여 온실가스 배출량을 산정하였다. 실제 교통망의 3지 신호교차로를 대상으로 분석한 결과 비첨두시에는 대형 화물차에 능동적 보상 전략을 통해 지속적으로 우선권을 부여하는 것이 온실가스 및 연료소모량 감축에 효과가 있는 것으로 분석되었으며, 대형 화물차의 정지 감소로 인해 총통행시간도 개선되는 것으로 나타났다. 이러한 결과로부터 제안된 알고리즘은 교통량이 많지 않은 공단 입구의 좌회전 현시에 효과적으로 적용될 수 있을 것으로 판단된다.

• International Journal of Automotive Technology
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• 제6권3호
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• pp.221-227
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• 2005

Aim of this study is to investigate an aerodynamic effect of a drag-reducing device on a heavy-duty truck. The vehicle experiences two different kinds of aerodynamic forces such as drag and uplifting force (or downward force) as it is traveling straight forward at constant speed. The drag force on a vehicle may cause an increase of the rate of fuel consumption and driving instability. The rolling resistance of the vehicle may be increased as result of the negative uplifting or downward force on the vehicle. A device named roof-fairing system has been applied to examine the reduction of aerodynamic drag force on a heavy-duty truck. As for a engineering design information, the drag-reducing system should be studied theoretically and experimentally for the best efficiency of the device. Four different types of roof-fairing model were considered in this study to investigate the aerodynamic effect on a model truck. The drag and downward force generated by vehicle has been obtained from numerical calculation conducted in this study. The forces produced on four fairing models considered in this study has been compared each other to evaluate the best fairing model in terms of aerodynamic performance. The result shows that the roof-fairing mounted truck has bigger negative uplifting or downward force than that of non-mounted truck in all speed ranges, and drag force on roof-fairing mounted truck has smaller than that of non-mounted truck. The drag coefficient $(C_D)$ of the roof-fairing mounted truck (Model-3) is reduced up to $41.3\%$ than that of non-mounted trucks (Model-1). A downward force generated by a roof-fairing mounted on a truck is linearly proportional to the rolling resistance force. Therefore, the negative lifting force on a heavy-duty truck is another important factor in aerodynamic design parameter and should be considered in the design of a drag-reducing device of a tractor-trailer. According to the numerical result obtained from present study, the drag force produced by the model-3 has the smallest of all in all speed ranges and has reasonable downward force. The smaller drag force on model-3 with 2/3h in height may results of smallest thickness of boundary layer generated on the topside of the container and the lowest intensity of turbulent kinetic energy occurs at the rear side of the container.

• 한국수소및신에너지학회논문집
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• 제35권2호
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• pp.121-128
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• 2024

In this study, a dynamic simulation model of a heavy-duty truck, equipped with a fuel cell power-train, has been developed and the dynamic behavior of the fuel cell stack has bee investigated using. Output change simulations were performed according to several drive cycle load change of a fuel cell truck. Mathworks' Simulink and Simscape program were used to develop the model. The model is comprised of fuel cell power train, power converter system and truck vehicle part. The vehicle runs at targeted speed of the truck, which is set as the load of the system. The dynamic behavior of the fuel cell stack according to the weight difference were analyzed, and based on this, the dynamic characteristics of the fuel cell output power and battery state with simple load was analyzed.

• 한국정밀공학회지
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• 제18권3호
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• pp.90-98
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• 2001

In this paper, the development of exclusive control valve for improving the performance of truck cab tilting system is discussed. Cab tilting system is implemented to the heavy truck for the convenience of driver. However when tilting up or down, sudden swing of cab has brought discredit on user. To improve this phenomena it is inevitable to use counter balance valve. But because of high pressure and low flow characteristic, general counter balance valve is unsuitable to cab tilting system. Therefore, this paper presents the developments of exclusive return pressure control valve which prevents sudden swing of cab and verify the validity of design through the computer simulation.

• 대한토목학회논문집
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• 제12권4호
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• pp.107-116
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• 1992

도로교의 안전수준에 영향을 미치는 것은 주로 과적중차량이다. 계속 증가하는 과적중차량의 문제는 오래전 부터 매우 심각한 상태인 것으로 지적되어오고 있다. 따라서 여러나라에서 차량하중의 특성에 관한 연구가 활발히 이루어지고 있으며, 일부에서는 이러한 변화를 반영하기 위하여 도로교 설계활하중을 개선하였다. 본 연구에서는 차량하중 및 통행특성의 자료를 수집하여 차량형식, 차량총중량, 축중분배, 차종혼입율, 연행특성 등을 분석하고 합리적인 모형을 제시하였다. 또한 차량하중이 도로교에 미치는 하중효과를 교량형식에 따라 분석하여 현행 도로교 설계관련 규정들이 내포하고 있는 안전수준에 대한 분석을 실시하였다.