• Title/Summary/Keyword: heavy truck

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Vibration Analysis of a Heavy Truck via Road Tests (주행시험에 의한 대형 트럭의 주행진동 특성 분석)

  • Song, Oh-Seop;Nam, Kyung-Mo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.3
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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.

Comparison of Vibration Characteristics of a Multi-leaf Spring and a Tapered Leaf Spring of a Heavy Truck (대형트럭 다판 스프링과 테이퍼 판스프링의 진동특성 비교)

  • Oh Chae-Youn;Moon Il-Dong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.2 s.233
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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.

Hydropneumatic Modeling and Analysis of a Heavy Truck Cabin Air Suspension System (대형 트럭 캐빈 공기 현가장치의 유공압 모델링 및 해석)

  • Shin, Hang-Woo;Choi, Gyoo-Jae;Lee, Kwang-Heon;Ko, Han-Young;Cho, Gil-Joon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.4
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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.

The Improvement of Cab Tilting system in Heavy Truck and the Development of Program for Automatic Design Parameter Selection (트럭 캡 틸팅 시스템의 성능 향상 및 설계 파라미터의 자동 선정 프로그램의 개발)

  • Park, Sung-Hwan;Lee, Jin-Kul
    • Journal of Institute of Control, Robotics and Systems
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    • v.5 no.4
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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.

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Hydropneumatic Modeling and Dynamic Characteristic Analysis of a Heavy Truck Semi-active Cabin Air Suspension System (대형 트럭 반능동형 캐빈 공기 현가시스템의 유공압 모델링 및 동특성 해석)

  • Lee, Kwang-Heon;Jeong, Heon-Sul
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.2
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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.

An Algorithm for Heavy Duty Truck Priority on Left-turn to Reduce Greenhouse Gas Emissions (온실가스 감축을 위한 대형 화물차 좌회전 우선신호 알고리즘 개발)

  • Yang, Se Jung;Kim, Suhyeon;Kim, Hyo Seung;Lee, Chungwon
    • Journal of Korean Society of Transportation
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    • v.31 no.5
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    • pp.60-70
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    • 2013
  • This study aims to develop a truck priority on left-turn algorithm that can reduce greenhouse gas emissions by reducing heavy duty truck's stops at signalized intersection. The signal priority is granted for a left-turn phase, because heavy duty trucks can deteriorate left-turn traffic flow due to the low acceleration or deceleration rate and large turn radius. Truck priority allows to provide the stable speed control for heavy duty truck, and reduces emissions at the signal intersection. Also, two signal recovery strategies are compared for various traffic conditions. This study analyzes the effectiveness of truck priority such as greenhouse gas emissions and fuel consumption reduction, and total travel time saving using the PARAMICS and Comprehensive Modal Emissions Model (CMEM). The results show that signal priority for heavy duty trucks has an effect on reducing greenhouse gas emissions and fuel consumptions at non-peak hour. Also, it shows decreasing total travel time due to reducing truck stops.

AERODYNAMIC EFFECT OF ROOF-FAIRING SYSTEM ON A HEAVY-DUTY TRUCK

  • KIM C. H.;YOUN C. B.
    • International Journal of Automotive Technology
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    • v.6 no.3
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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.

The Development of Exclusive Control Valve for Improving the Performance of Truck Cab Tilting System (트럭 캡 틸팅 시스템의 성능 향상을 위한 전용 제어 밸브의 개발)

  • Park, Sung-Hwan;Lee, Jin-Kul
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.3
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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.

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A Study on Bridge Live Loads and Traffic Modes (도로교 차량하중 및 통행특성에 관한 연구)

  • Kim, Sang Hyo;Park, Hung Seok
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.12 no.4
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    • pp.107-116
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    • 1992
  • The structural integrity of bridges is mainly damaged by overloaded heavy vehicles. The increasing volumes of overloaded heavy vehicles has been indicated as serious state. As results several countries have revised their bridge load codes. However, because of variety of truck types and their weights it is difficult to develop rational standard truck loads. In addition the common practice that only one design configuration of standard truck is adopted to design variety of bridges causes further difficulties. The objective of the study is to investigate the statistical characteristics of vehicle loadings based on survey data collected, in which some major factors, such as vehicle configurations, vehicle weights, traffic modes, etc., are incorporated. The vehicle load effects due to single presence of heavy truck are also tested with several short-span bridges and probabilistic characteristics of current design practices are evaluated.

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Nonlinear collision analysis of heavy trucks onto steel highway guard fences

  • Itoh, Yoshito;Liu, Chunlu;Usami, Koichi
    • Structural Engineering and Mechanics
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    • v.12 no.5
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    • pp.541-558
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    • 2001
  • The design specifications of guard fences in Japan were reexamined and the revised specifications were implemented from April 1999. Because of the huge consumption in time and cost to test the performances of full-scale guard fences in the field, some assumptions are adopted while modifying the design specifications, and numerical analyses are necessary to confirm the impact performance and safety level of new types of steel highway guard fences. In this study, the finite element models are developed for the heavy trucks and steel highway guard fences to reenact their behaviors, and the solution approach is carried out using nonlinear dynamic analysis software of structures in three dimensions (LS-DYNA). The numerical simulation results are compared with the full-scale on-site testing results to verify the proposed analysis procedure. The collision process is simulated and it is also made possible to visualize the movement of the truck and the performances of guard fences. In addition, the energy shift of the truck kinetic energy to the truck and guard fence Internal energy, and the energy absorption of each guard fence component are studied for the development of a new design methodology of steel highway guard fences based on the energy absorption capacity.