• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.2
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• pp.191-197
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• 2016

RCAR low speed impact test estimates repair cost of the impacted vehicle. In this study, for a mid-size vehicle front body model, structural performance for RCAR low speed impact were analyzed with changing the bumper stay shape and size. First, for improving the impact load transfer mechanism to side member the stay rear section shape at connecting area with side member was modified and the stay outer was redesigned to be normal to the barrier. Next, the investigation on stay thickness effect was carried out and the performances of several models with different forming shape were compared. The final design showed 13mm decrease in the maximum barrier intrusion distance and greatly reduced side member deformation. Additional analyses explained the validity of the final design.

• Journal of Navigation and Port Research
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• v.29 no.1 s.97
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• pp.9-15
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• 2005

To design ship channel is one of important factors for planning and developing a port. In most case, the core factors for designing ship channel are the layout and width of channel provided the net underkeel clearance is secured to be safe enough to pass. In this study, Variable Bumper Area(VBA) model is applied to design and assess ship channel. This model reflects ship's particular, ship domain theory, ship speed and mariner's ship handling skill and experience, especially external forces which cause leeway, set and drift and the change of ship maneuvering characteristics. A real time, full mission shiphandling simulator is used to analyze ship dynamic data according to mariner's ship control, external forces, ete. This model defines Domain degree and Domain-index for assessing the efficiency and safety of the channel. The proposed model is applied to Ulsan new port plan which has a channel width of 1.5 times the length of the largest vessel, a radius of 5 times the length of the largest vessel in a curve of 57 degree centerline angle and SBM facility adjacent to the lateral edge of channel. The result of this study shows that the width of the channel and radius of channel curve are suitable for the target ship but the difficulty of ship handling is caused by the large course change and SBM located in the vicinity of channel.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.231-235
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• 2005

Rapid increase of maritime traffic volume and the increase of vessel size make it indispensible for the fairway designer to estimate the traffic capacity of a fairway at its early design stage. In this paper, as one of the methods to estimate the maritime traffic capacity of a fairway, operating rate of a fairway is defined and reviewed together with its basic characteristics, which is a brief estimation model based on bumper model around a ship. The method is applied to the approach channels of major harbors in Korea to give some guidelines on the acceptable traffic capacity of a fairway. In spite of its simplicity, this method can be used as an effective tool to discriminate whether the principal dimension of a fairway is enough or not from the viewpoint of maritime traffic capacity at its initial design stage.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.6
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• pp.603-608
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• 2014

In the maritime traffic environment, the near-miss between vessels is the situation approaching on collision course but collision accident is not occurred. In this study, in order to calculate the near-miss between navigating vessels, the discriminating equation using ship bumper theory and vessel position clustering methods are proposed. Applying proposed module to the vessel trajectories of the WANDO waterway, we assessment navigational risk factors of vessel type, navigational speed, meeting situation.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.11a
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• pp.262-266
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• 2002

본 연구에서는 가상환경 및 시뮬레이션에서 활용이 가능한 인체 모델을 개발하였다. 한국인 인체 측정 자료를 바탕으로 각 지체에 대한 기구학적 특성치와 상관관계를 얻고 인체 모델을 구성하였다. 인체 모델은 17개의 독립된 지체들로 구분되며 조인트로 연결된다. 구성된 모델은 가상환경의 신 그래프(scene graph)상에 자료화되고 DCS를 이용하여 애니메이션이 가능하도록 하였다. Madymo를 이용하여 차량 운전자의 전방 충돌 및 범퍼 통과시 지체의 거동을 해석하고 그 결과 값을 변환하여 OpenGL Performer 라이브러리를 통해 가상 공간에 가시화하였다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1992.03a
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• pp.115-130
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• 1992

The analysis of thermoplastic automotive bumpers needs not only characterizations of the thermomechanical properties of thermoplastic materials but also the finite element method which can solve the problems with a large deflection, an elastic-inelastic deformation, and a change of a contact state. This paper describes the modeling techniques in the finite element analysis in order to get a good prediction of thermoplastic bumper behaviors. Simplification effects of a complex geometry of thermoplastic bumpers are studied by comparing the results from static loading tests and the finite element analysis.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.169-174
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• 2004

To design ship channel is one of important factors for planning and developing a port. In most case, the core factors for designing ship channel are the layout and width of dvnnel provided the net underkeel clearance is assessed as safety. In this study, Variable Bumper Area(VBA) model is applied to design and assess ship channel. This model reflects ship's principle dimension, ship domain theory, ship speed, conning officer's ship handling skill and experience and all external forces which cause leeway, set and drift and the change of ship maneuvering characteristics. Full Mission Ship Handling Simulator is used to analyze ship dynamic data according to conning officer's ship control, external forces, etc. This model uses Domain-index for assessing the efficiency and safety of the channel. The proposed model is applied to Ulsan new port plan which has a channel width of 1.5 times the length if the largest vessel, a radius if 5 times the length of the largest vessel in a curve of 57 degree centerline angle and SBM facility adjacent to the lateral edge if channel. The result of this study shows tint the width and radius of channel curve are suitable for the target ship but the difficulty of ship handling is caused by the large course change and SBM located in the vicinity if channel.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.670-678
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• 2018

In coastal waters where the traffic volume of the ship is high, there is a high possibility of a collision accident because complicated encounter situations frequently occurs between ships. To reduce the collision accidents at sea, a quantitative collision risk assessment is required in addition to the navigator's compliance with COLREG. In this study, a new collision risk assessment system was developed to evaluate the collision risk on ship's planned sailing routes. The appropriate collision risk assessment method was proposed on the basis of reviewing existing collision risk assessment models. The system was developed using MATLAB and it consists of three parts: Map, Bumper and Assessment. The developed system was applied to the test sea area with simple computational conditions for testing and to actual sea areas with real computational conditions for validation. The results show the length of own ship, ship's sailing time and sailing routes affect collision risks. The developed system is expected to be helpful for navigators to choose the optimum safe route before sailing.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.14-14
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• 2017

본 연구는 트랙터 주행노면의 토양 특성이 트랙터 승차진동에 미치는 영향을 분석하는 것을 목표로 하였다. 여러 토양조건에서 실제 트랙터 주행실험을 진행하는 것은 어렵기 때문에, 상용 CAE 프로그램을 이용하여 트랙터를 모델링하고 시뮬레이션을 진행하였다. 이를 통해 여러 토양조건에 따른 승차진동의 특성을 비교, 분석하였다. 모델의 유의성은 트랙터 아스팔트 주행실험을 통해 진동데이터를 획득하고 실측 진동 데이터와 시뮬레이션을 통해 얻어진 진동 데이터를 분석해 검토하였다. 이 때, 노면 토양의 특성에 따라서 트랙터가 장애물을 만났을 때 순간적인 진동 특성을 분석하기 위해서 트랙터 주행 노면을 사인범퍼(sine-bumper) 노면으로 설정하고 주행실험 및 시뮬레이션을 진행하였다. 본 연구에서는 강체 노면, Heavy clay, North Gower Clay Loam 토양, Grenvile Loam 토양의 네 가지 노면 조건을 분석하였다. 분석 결과 침하가 발생하지 않는 강체 노면보다 침하가 발생하는 세 가지 토양 조건에서 장애물에 따른 순간적인 진동이 더 크게 나타나는 것을 확인할 수 있었다. 다만 승차진동이 토양 파라미터와 단순히 선형적인 관계만을 보이는 것은 아니라는 것도 확인할 수 있었다. 이 후, North Gower Clay Loam 토양 조건에서 트랙터 속도에 따른 시뮬레이션 진행 결과를 분석하였을 때, 토양 침하가 발생하는 토양 조건에서도 속도가 증가함에 따라서 진동 크기가 증가하는 것을 확인할 수 있었다.

• Journal of Aerospace System Engineering
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• v.13 no.6
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• pp.43-51
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• 2019

The aircraft vertical acceleration from the excitation of the road surface in the taxing mode is a main factor with a negative effect on the boarding quality of pilots and passengers. In this paper, we propose an appropriate control method to improve the boarding quality of the MR damper landing gear. The proposed control method is Skyhook Control Type 2, which feeds the aircraft vertical acceleration back in addition to the aircraft vertical velocity. Since Skyhook Control Type 2 factors the velocity and acceleration of the upper mass, it can be expected to exceed the control performance of the existing Skyhook Control that factors only the upper mass velocity. For the simulation, the bumper type road surface was selected as a ground surface, and the landing gear model constructed with RecurDyn and the controller designed with Simulink were co-simulated. The control effect of Skyhook Control Type 2 was verified by comparing and analyzing the RMS and maximum value of the upper mass acceleration according to the taxing speed and control method.