• 에너지공학
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• 제29권3호
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• pp.64-73
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• 2020

본 논문은 전기 자동차의 충·방전 장소를 고려한 도시별 일부하 곡선 산출을 위한 방법론을 제시하였다. 즉, 특정 도시에서 전기 자동차 충·방전에 의해 발생되는 부하량이 전력 그리드에 미치는 영향을 용이하게 파악할 수 있도록 전기 자동차의 충·방전 장소를 고려한 도시별 일부하 곡선 산출 알고리즘을 제시하였다. 구체적으로는 PEVs 점유율 시나리오에 따라 도시내의 전기차 충·방전 장소별 즉, 직장 및 가정에 대하여 오전에 직장에 도착한 전기차에 대해 그리드에 방전을 그리고 오후에 가정에 도착한 전기차에 대해 충전을 시행하는 가정을 수립한 후 오전 직장 도착 차량운행 특성과 SMP 요금제를 동시에 반영한 PEVs 방전 전력을 산정하였다. 그리고 오후에 가정 도착 차량운행 특성과 TOU 요금제를 동시에 고려한 PEVs충전 전략에 대해 각각 서울시를 대상으로 충·방전 전력 형태별로 일부하곡선을 산출한 후 기존 부하와 합산하여 그리드에 미치는 영향 평가를 비교 분석하였다.

• 자동차안전학회지
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• 제6권2호
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• pp.5-11
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• 2014

Front side member of the front impacted vehicle plays a key role in minimizing the impacting load transferred to the compartment. To perform that required function, axial collapse should be dominant during side member crashing and, prior to designing side member, it is crucial to minimize bending moment occurred at the front end. In this study, for FE model of a SUV front body, front impact analyses were carried to find out bumper stay design which effectively develope axial collapse in the side member. As a previous work, the thickness of side member reinforcement were changed. Next, the inner thickness of bumper stay was increased. Also, the bead shape and location were modified. Final front body model showed much more axial collapsed mode and enhanced crash performance. In addition, a stay of octagon section was adopted and that model exhibited distinctive increase in impact energy absorption.

• Structural Engineering and Mechanics
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• 제71권4호
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• pp.391-405
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• 2019

Compared to the ambient vibration test mainly identifying the structural modal parameters, such as frequency, damping and mode shapes, the impact testing, which benefits from measuring both impacting forces and structural responses, has the merit to identify not only the structural modal parameters but also more detailed structural parameters, in particular flexibility. However, in traditional impact tests, an impacting hammer or artificial excitation device is employed, which restricts the efficiency of tests on various bridge structures. To resolve this problem, we propose a new method whereby a moving vehicle is taken as a continuous exciter and develop a corresponding flexibility identification theory, in which the continuous wheel forces induced by the moving vehicle is considered as structural input and the acceleration response of the bridge as the output, thus a structural flexibility matrix can be identified and then structural deflections of the bridge under arbitrary static loads can be predicted. The proposed method is more convenient, time-saving and cost-effective compared with traditional impact tests. However, because the proposed test produces a spatially continuous force while classical impact forces are spatially discrete, a new flexibility identification theory is required, and a novel structural identification method involving with equivalent load distribution, the enhanced Frequency Response Function (eFRFs) construction and modal scaling factor identification is proposed to make use of the continuous excitation force to identify the basic modal parameters as well as the structural flexibility. Laboratory and numerical examples are given, which validate the effectiveness of the proposed method. Furthermore, parametric analysis including road roughness, vehicle speed, vehicle weight, vehicle's stiffness and damping are conducted and the results obtained demonstrate that the developed method has strong robustness except that the relative error increases with the increase of measurement noise.

• 한국융합학회논문지
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• 제11권4호
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• pp.173-177
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• 2020

본 연구에서는 현재 전복 사고가 자주 발생하는 Model A와 Model B의 중형 세단 차량들의 사이드 도어들을 구조 해석으로 서로 비교한다. 구조해석 결과, 두 모델 모두 전복 사고나 충격 시 하중이 작용되는 부분에서 최대 변형이 일어났고 2개의 모델 중 Model A가 Model B와 비교하면 충격력을 더 견딜 수 있다. 또한 도어의 모서리 부분에서 최대 응력이 일어났고 Model B가 Model A보다 2.5 배 더 응력이 커진다. 충돌 사고가 일어날 시, 2개의 모델 중 그 최대 응력이 작은 Model A가 Model B와 비교하면 더 큰 충격력을 견딜 수 있다. Model B가 Model A보다 더 큰 변형량을 갖는 것으로 보아 측면 충돌 사고에서는 Model A보다 위험할 것으로 사료된다. 차종별 차량 옆문의 충돌해석을 적용함으로서 본 논문에서의 연구 결과는 미적인 설계를 적용할 수 있는 융합 연구자료로서 유리하다고 여겨진다.

• 대한안전경영과학회지
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• 제18권4호
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• pp.107-114
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• 2016

The efficiency of the purchasing and procurement logistics is important in automotive industry. The rationalization of production system is directly impact on productivity and quality. For this reason importance of logistics is high. Despite we are continuously making effort, our country are still below the level than developed country on logistics efficiency. Rising labor costs is an important factor in increasing logistics costs. So workforce reduction in logistics department is a large part. We deal with A-company inbound logistics, especially procurement logistics in automotive logistics as research object. So in this study we do research on work load balance about workers. We do research on 1,475 kinds of components in procurement process. We applied work load balance algorithm on chassis, final, sequence, trim warehouses workers. According to number of workers and average M/H, algorithm is applied in two ways. After applied work load balance algorithm we reduced numbers of workers from 28 to 20 and improved worker load balance rate from 47.1% to 93.7%.

• 한국정밀공학회지
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• 제23권6호
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• pp.72-80
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• 2006

Electric Power Steering (EPS) mechanism has become widely equipped in passenger vehicle due to the increasing environmental concerns and higher fuel efficiency. This paper describes the development of concurrent simulation technique and simulation integration technique of EPS control system with a dynamic vehicle system. A full vehicle model interacting with EPS control algorithm was concurrently simulated on a single bump road condition. The dynamic responses of vehicle chassis and steering system resulting from road surface impact were evaluated and compared with proving ground experimental data. The comparisons show reasonable agreement on tie-rod load, rack displacement, steering wheel torque and tire center acceleration. This concurrent simulation capability was employed fur EPS performance evaluation and calibration as well as for vehicle handling performance integration and synthesis.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.472-475
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• 2003

Electric Power Steering (EPS) mechanism has become widely equipped in passenger vehicle due to the environmental consciousness and higher fuel efficiency. This paper describes the development of co-simulation technique and simulation integration technique of EPS control system with dynamic vehicle model. A full vehicle model interacted with EPS control algorithm is concurrently simulated on a single bump road condition. Dynamic responses of vehicle chassis and steering system resulting from road surface impact are evaluated and compared with proving ground experimental data. The comparisons will show reasonable agreement on tie-rod load. rack displacement, handle-wheel torque and tire center acceleration. This developed simulation capability can be used for EPS performance evaluation and calibration as well as for vehicle handling performance integration and synthesis.

• 한국재난정보학회 논문집
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• 제13권1호
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• pp.73-80
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• 2017

이 논문에서는 프리캐스트 바닥판 위를 이동하는 차량하중에 의한 바닥판 접합거동 특성을 분석하였다. 하중 재하를 위하여 프레임을 제작하였고 각 측정 장치를 활용하여 거동을 파악하였다. 바닥판의 정적응답을 검토하여 이론값과 비교하였고 그 특성은 매우 합리적임을 알 수 있었다. 또한, 동적영향 평가를 위하여 가속도, 속도 및 변위를 측정하여 시험에서 이동하중의 특성을 분석하였다. 이동하중에 의한 동적응답을 위하여 바닥판 진동수를 측정한 결과 하중 범위 변화에 따라 진동 특성도 민감하게 반응하는 것으로 나타났다. 결과적으로 연결부의 동적 응답은 연결방법에 따라 특성이 다르므로 설계에 주의를 기울여야 할 것으로 판단된다.

• Structural Engineering and Mechanics
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• 제9권6호
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• pp.569-588
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• 2000

The plastic collapse loads and their locations are predicted for a class of tapered, initially curved, and transversely corrugated cantilevered beams subjected to static tip loading. Results of both closed form and finite element solutions for several rigid perfectly plastic and elastic perfectly plastic beam models are evaluated. The governing equations are cast in nondimensional form for efficient studies of collapse load as it varies with beam geometry and the angle of the tip load. Static experiments for laboratory-scale configurations whose taper flared toward the tip, complemented the theory in that collapse occurred at points about 40% of the beams length from the fixed end. Experiments for low speed impact loading of these configurations showed that collapse occurred further from the fixed end, between the 61% and 71% points. The results may be applied to the design of safer highway guardrail terminal systems that collapse by design under vehicle impact.

• Computers and Concrete
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• 제22권1호
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• pp.123-132
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• 2018

Reinforced concrete (RC) columns which are the main vertical structural members are exposed to several static and dynamic effects such as earthquake and wind. However, impact loading that is sudden impulsive dynamic one is the most effective loading type acting on the RC columns. Impact load is a kind of impulsive dynamic load which is ignored in the design process of RC columns like other structural members. The behavior of reinforced concrete columns under impact loading is an area of research that is still not well understood; however, work in this area continues to be motivated by a broad range of applications. Examples include reinforced concrete structures designed to resist accidental loading scenarios such as falling rock impact; vehicle or ship collisions with buildings, bridges, or offshore facilities; and structures that are used in high-threat or high-hazard applications, such as military fortification structures or nuclear facilities. In this study, free weight falling test setup is developed to investigate the behavior effects on RC columns under impact loading. For this purpose, eight RC column test specimens with 1/3 scale are manufactured. While drop height and mass of the striker are constant, application point of impact loading, stirrup spacing and concrete compression strength are the experimental variables. The time-history of the impact force, the accelerations of two points and the displacement of columns were measured. The crack patterns of RC columns are also observed. In the light of experimental results, low-velocity impact behavior of RC columns were determined and interpreted. Besides, the finite element models of RC columns are generated using ABAQUS software. It is found out that proposed finite element model could be used for evaluation of dynamic responses of RC columns subjected to low-velocity impact load.