• 한국군사과학기술학회지
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• 제12권2호
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• pp.236-247
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• 2009

In Korea, the driving system restriction criteria is strictly applied(gross weight 400kN, axial load 100kN). Especially after the Seoungsu Bridge accident, safety factor has been strictly applied. The Safety factor is applied to the cumulative results for each steps like design, construction, maintenance of the Bridge. Because of it, the bridge is undervalued compared to its capacity. So, this generates loss for both private and military sector(eg. logistical delays, structural damage, etc.). But analyzing data from many existing researches we have confirmed that the military heavy vehicle may pass through the first class bridges. In consequence, this study have focused on determining whether HETS vehicles can pass over the first class bridge, without safety issues, using MIDAS structural analysis program. The results have confirmed that the military heavy vehicle may pass over the bridge.

• Structural Engineering and Mechanics
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• 제12권4호
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• pp.409-428
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• 2001

The characteristics of dynamic wheel loads of heavy vehicles running on bridge and rigid surface are investigated by using three-dimensional analytical model. The simulated dynamic wheel loads of vehicles are compared with the experimental results carried out by Road-Vehicles Research Institute of Netherlands Organization for Applied Scientific Research (TNO) to verify the validity of the analytical model. Also another comparison of the analytical result with the experimental one for Umeda Entrance Bridge of Hanshin Expressway in Osaka, Japan, is presented in this study. The agreement between the analytical and experimental results is satisfactory and encouraging the use of the analytical model in practice. Parametric study shows that the dynamic increment factor (DIF) of the bridge and RMS values of dynamic wheel loads are fluctuated according to vehicle speeds and vehicle types as well as roadway roughness conditions. Moreover, there exist strong dominant frequency resemblance between bounce motion of vehicle and bridge response as well as those relations between RMS values of dynamic wheel loads and dynamic increment factor (DIF) of bridges.

• 한국ITS학회 논문지
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• 제14권4호
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• pp.52-61
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• 2015

승용차 환산계수는 도로의 서비스 수준 및 용량 분석 등에 활용되는 자료이다. 본 연구에서는 개별차량자료를 활용하여 차로수별로 국토교통부에서 구분하고 있는 12가지 차종에 대하여 승용차 환산계수를 산출하였다. 산출결과 차종의 등급이 높을수록, 차로수가 많을수록, 주말일수록 승용차 환산계수의 값이 큰 것으로 나타났다. 승용차 환산계수를 활용하여 중차량 보정계수를 산출하였으며, 4, 6차로에서는 도로용량편람에서 제시한 결과와 비교했을 때 상대적으로 그 값이 작은 것으로 나타났다. 또한 차로수별로 중차량 비율에 따른 평균 승용차 환산계수 변화 모형을 추정하였으며, 2차로에서 PCE에 미치는 중차량의 영향이 가장 큰 것으로 나타났다. 이러한 연구결과는 다차로에서 중차량의 영향이 적고 주말의 통행은 상대적으로 업무통행 차량이 적기 때문으로 판단된다.

• Coupled systems mechanics
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• 제3권2호
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• pp.147-170
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• 2014

In the recent times, dimensions of heavy load carrying vehicle have changed significantly incorporating structural flexibility in vehicle body. The present paper outlines a procedure for the estimation of bridge response statistics considering structural bending modes of the vehicle. Bridge deck roughness has been considered to be non homogeneous random process in space. Influence of pre cambering of bridge surface and settlement of approach slab on the dynamic behavior of the bridge has been studied. A parametric study considering vehicle axle spacing, mass, speed, vehicle flexibility, deck unevenness and eccentricity of vehicle path have been conducted. Dynamic amplification factor (DAF) of the bridge response has been obtained for several of combination of bridge-vehicle parameters. The present study reveals that flexible modes of vehicle can reduce dynamic response of the bridge to the extent of 30-37% of that caused by rigid vehicle model. However, sudden change in the bridge surface profile leads to significant amount of increment in the bridge dynamic response even if flexible bending modes remain active. The eccentricity of vehicle path and flexural/torsional rigidity ratios plays a significant role in dynamic amplification of bridge response.

• Journal of Biosystems Engineering
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• 제37권3호
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• pp.148-154
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• 2012

Purpose: In order to improve road-friendliness of heavy vehicles, a fuzzy hybrid control strategy consisting of a hybrid control strategy and a fuzzy logic control module is proposed. The performance of the proposed strategy should be effectively evaluated using a hardware-in-the-loop (HIL) simulation model of a semi-active suspension system based on the fuzzy hybrid control strategy prior to real vehicle implementations. Methods: A hardware-in-the-loop (HIL) simulation system was synthesized by utilizing a self-developed electronic control unit (ECU), a PCI-1711 multi-functional data acquisition board as well as the previously developed quarter-car simulation model. Road-friendliness of a semi-active suspension system controlled by the proposed control strategy was simulated via the HIL system using Dynamic Load Coefficient (DLC) and Dynamic Load Stress Factor (DLSF) criteria. Results: Compared to a passive suspension, a semi-active suspension system based on the fuzzy hybrid control strategy reduced the DLC and DLSF values. Conclusions: The proposed control strategy of semi-active suspension systems can be employed to improve road-friendliness of road vehicles.

• 전산구조공학
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• 제10권4호
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• pp.337-347
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• 1997

통행차량에 의한 도로교의 동적응답은 차량이나 교량의 다양한 특성에 따라 변화하는 특성을 가지고 있다. 본 연구에서는 중차량의 통행에 의한 동적응답확대계수의 확률적인 특성을 해석적인 기법으로 분석하였다. 도로교 통행차량들 중에서 대표적인 중차량인 텐덤축트럭과 세미트레일러를 대상으로 하여 동적응답확대계수를 평가하고, 이들을 동적재하시험의 결과와 비교하여 해석기법의 타당성을 검토하였다. 차량형식, 총중량, 노면조도, 재하차량수, 재하위치 등에 따른 동적응답확대계수의 확률적 특성의 변화를 분석하고 현행 시방서 기준과 비교하였다.

• 한국자동차공학회논문집
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• 제19권3호
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• pp.73-82
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• 2011

Most of countries start to restrict the emission gases of vehicles especially CO2 because of the global warming. Many vehicle companies including Toyota have launched various HEVs to satisfy the restriction laws and to improve the vehicle's efficiency. However, development for heavy-duty hybrid system is not plentiful rather than the passenger car. In this study, we choose the optimal size of engine, motor and battery for heavy-duty hybrid systems using dynamic programming. Also we analyze the correlation of the system's cost and efficiency because the added cost of vehicle to make the hybrid system is very important factor for the manufacturing companies. Finally, this study suggests a method to choose the appropriate system components size considering its performance and the cost. With this method, it is possible to select the component size for various systems.

• 한국도로학회논문집
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• 제7권3호
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• pp.43-52
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• 2005

도로분류체계는 도로의 기능. 설계기준을 정의하기 위한 기초가 된다. 본 연구는 요인분석을 활용한 일반국도 유형분류에 대해 다루고 있다. 이를 위해 2004년도 상시 교통량 조사지점에서 수집된 교통자료를 이용한 요인분석을 수행함으로써 일반국도를 유형별로 분류하였다. 적용된 변수는 총 9개로 AADT(연평균 일교통량), $K_{30}$(설계시간계수) $D_{30}$(중방항계수), 중차량 비율, 주간 교통량 비율, 첨두율, 일요일 계수, 휴가철 계수, 그리고 COV(변동계수)이다. 요인분석 결과, 교통량 변동 특성 요인과 중차량 및 방향별 특성요인이 추출되었다. 군집분석 결과 전체 353개 상시지점이 3개의 그룹으로 분류되었으며 그룹 I은 관광부도로, 그룹 II는 지방부도로, 그룹 III은 도시부도로로 판단된다.

• 한국융합학회논문지
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• 제7권1호
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• pp.177-182
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• 2016

중공업과 군사목적으로 사용되는 궤도차량은 고중량의 차체를 버티기 위해 차체에서 전달되는 하중으로 기동륜을 감싸고 있는 링크는 큰 힘을 받게 되는데, 이 발생된 힘은 궤도전체의 내구성 저하를 야기하게 된다. 본 논문에서는 3가지의 상용화된 궤도 패드의 형상들을 가진 모델들을 설계하고, 내구성 저하로 발생될 수 있는 궤도패드의 마모와 링크의 파손을 효과적으로 줄일 수 있는 모델을 고안하였다. 또한 본 연구 결과를 궤도차량 설계에 접목함으로써, 파손방지와 내구성향상을 위한 안전설계에 기여할 수 있으며, 패드 형상의 디자인적인 요소를 융합기술에 접목하여 그 미적인 감각을 나타낼 수 있다.

• Journal of Korean Society for Atmospheric Environment
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• 제16권E2호
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• pp.69-77
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• 2000

Measurements of non-methane hydrocarbons (NMHC) were carried out in the Sangdo tunnel and on a nearby roadway in Seoul during the during the periods of heavy(low speed with ∼20km h(sup)-1) and light(high speed with ∼60kmh(sup)-1) traffic in February 2000. In the tunnel, the total NMHC levels during the heavy traffic period were higher than those during the light traffic period by a factor of 2. This was due to the increase of emissions at the low vehicle speed period and the higher dilution effect derived from faster flow of tunnel air at the high vehicle speed period. The average total NMHC concentration in the tunnel was 1.7 times as high as that on the roadway. The species with the highest concentration in the tunnel was ethylene(50.1 ppb), followed by n-butane(34.1 ppb) and propane (21.9 ppb). The concentration ranking in the tunnel was generally in good agreement with that on the roadway, suggesting that the NMHC compositions in the tunnel and on the nearby roadway were primarily determined by vehicle exhausts. However, the NMHC compositions in the Sangdo tunnel do not agree well with other foreign study results, reflecting that the characteristics of vehicle exhausts of Seoul is different from those of other cities. The most prominent difference between this study and other studies is the high mass fractions of butanes and propane. It was be attributed to the wide use of butane-fueled vehicles.