• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2002.05a
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• pp.47-50
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• 2002

산업이 발달함에 따라 대량의 화물을 빠르게 운반할 수 있는 해상운송수단의 수요가 증가하게 되고 이로 인하여 해상 선박 간 충돌사고가 빈번히 발생하게 되었다 선박 충돌은 주로 조선하는 사람들의 관습, 습관의 차이, 부주의, 판단오류 등의 이유로 발생한다. 연구자들은 선박 충돌을 방지하기 위하여 조선에 관련된 많은 부분을 지능화한 지능형 충돌회피시스템 개발에 노력을 기울이고 있다. 선박을 비롯한 자율운동체의 충돌방지 기법은 비행체, 수중운동체, 자율로봇 등 영역 특성을 달리하는 다양한 분야에서 연구되어오고 있다 기존 연구들의 충돌방지는 주로 장애물의 공간적 특성에 기반하고 있다. 이에 개체의 움직임을 예측하여 시간적 요소를 가미하면 더욱 향상된 충돌방지가 가능하다. 특히, 선박은 느린 운동 특성과 조선법, 규격화된 통신수단의 발달로 인하여 상대편 선박의 이동 예측이 용이하므로 이를 적용하여 보다 향상된 충돌방지가 가능하다. 본 연구에서는 기존의 충돌회피기법의 과정에 예측을 추가한 예측기반 충돌회피모형을 제안하고 선박운항환경을 모의실험에 의하여 해당 모형 적용시 충돌회피 경로 산출의 안전성이 크게 개선됨을 보인다.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.127-132
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• 2018

One of the key issues in the Unmanned Aerial Vehicle (: UAV) technology is the collision avoidance. Specifically, the collision avoidance among multiple UAVs is critical to expand UAV applications to civil sector where large number of UAVs could be operated in the limited space. In this paper, we introduce a collision avoidance scheme based on Flying Ad Hoc Network (: FANET). The proposed scheme adopts collision avoidance mechanism used in wireless data communication networks. Using this scheme UAVs can not only communicate conventional user information, but also share flight information to avoid collision.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.369-377
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• 2014

In this paper, to recognize the collision behavior between a submerged floating tunnel(SFT) and underwater navigation vessel(UNV), both structures are modeled and analyzed. The SFT of collision point is modeled tubular section using concrete with steel lining. The other part of SFT is modeled elastic beam elements. Mooring lines are modeled as cable elements with tension. The under water navigation vessel is assumed 1800DT submarine and its total mass at collision is obtained with hydrodynamic added mass. The buoyancy force on SFT is included in initial condition using dynamic relaxation method. The buoyancy ratio (B/W) and the collision speed are considered as the collision conditions. As results, energy dissipation is concentrated on the SFT and that of the UNV is minor. Additionally, the collision behaviors are greatly affected by B/W and the tension of mooring lines. Especially, the collision forces are shown different tendency compare to vessel collision force of current design code.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.95-99
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• 2004

This paper describe inner-collision-characteristics of the ship structural plates when the projectile collides with plate-material using LS-DYNA3D which is general and useful finite element analysis tool in collision problem fields. The series analyses were carried out from high speed(41.56m／s-118.9m／s) to ultrahigh speed(544.05m／s-800m／s). Through these analyses we can approach empirical formula to estimate penetration limit of the ship structural plates with which the projectile of various speed collides.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.4
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• pp.92-100
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• 2015

The aim of this study is to evaluate the fracture characteristics of ductile fiber reinforced cement based composites with 1.5 volume ratio of polyvinyl alcohol and steel fiber by high velocity impact of steel projectile. We used gunpowder impact facility to evaluate the fracture characteristics of ductile fiber reinforced cement based composites by collision of steel projectile, and the impact velocity was from about 150 to 1,000m/s. The results of evaluation on the fracture characteristics of ductile fiber reinforced cement based composites were penetration grade, which is the kinetic energy more than three times of no-fiber reinforced specimen (Plain). In addition, ductile fiber reinforced cement based composites did not occurred critical damage other than the debris. In the case of mass loss, Plain specimen was proportional to kinetic energy of steel projectile, while ductile fiber reinforced cement based composites was not significantly affected by kinetic energy of steel projectile. In particular, this tendency had a close relationship with the fracture characteristics of back side of specimens, and the scabbing inhibiting efficiency of PVA specimen was higher than S specimen. In the results of verifying relationship between front and back side calculated by local damage, scabbing occurred at the region close to the back side in the ductile fiber reinforced cement based composites unlike Plain specimen. Thus, in this study, we examined principal fracture behaviors of ductile fiber reinforced cement based composites under collision of steel projectile, and verified that impact resistance performance was improved as compared to Plain specimen.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.318-323
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• 1998

사용 후 핵연료 수송용기의 충돌사고에 대한 안전성은 층격완충체의 층격흡수특성에 지배되며, 충격완충체의 충격홉수특성은 외부의 케이스와 내부 격막판 둥의 철제 구조물과 내부에 삽입된 충격흡수재의 변형특성에 지배를 받는다. 충격흡수재를 감싸주는 철제 케이스와 내부 격막판의 용접 접합부는 일부 부분이 제작공정상 부득이 부분용접의 접합형태를 갖기 때문에 판재나 완전 접된 부분에 비해 강도가 약해 충돌사고시 취약부위가 파단된다. 이러한 케이스 용접부의 파단은 충격완충체의 변형특성을 변화시켜 충격흡수거동이 달라지는 원인이 된다. 따라서, 본 연구에서는 용접 접합부의 강도특성을 수송용기의 자유낙하 충돌해석에 적용할 수 있는 해석모델을 구성하고 부분용접된 접합부의 파단강도가 수송용기의 충돌거동에 미치는 영향을 분석하였다.

• Composites Research
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• v.29 no.6
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• pp.363-368
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• 2016

This study performed a nonlinear finite element crash analysis of guardrail structures using supports made of composite materials. In this study, we used a new [0/90/90/0] laminated Boron fiber composite for resisting the crash effects. Based on the improved ground-structure interaction model, appropriate ground properties to the support were determined. In particular, the complex crash mechanism of guardrails was studied using various parameters. The parametric studies are focused on the various effects of car crash on the structural performance and thickness of supports. The numerical results for various parameters are verified by comparing those using existing steel materials.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.194-201
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• 2008

The launch vehicle upper stage generally executes collision and contamination avoidance maneuver after the satellite separation. Through this maneuver the satellite safely settles in its orbit and the launch vehicle moves away from the satellite with minimum contamination. In this paper collision and contamination avoidance maneuvers by foreign launch vehicles are analyzed. Criteria for satellite contamination during the avoidance maneuver is given for KSLV-I upperstage.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.01a
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• pp.181-182
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• 2017

게임에서 캐릭터와 몬스터 간, 캐릭터와 캐릭터 간, 피격처리 등을 위해서는 충돌처리가 필요하다. 본 논문에서는 Unity3D 엔진에서 지원하는 충돌처리 방법을 비교분석하였다. Unity3D 엔진에서 지원하는 충돌처리 방법은 Collider 방식과 Raycast 방식이 있으며, Collider 방식은 정적이거나 속도가 아주 느린 오브젝트에 사용하고, Raycast방식은 속도가 빠른 투사체를 구현하는데 적합하다.

• Journal of the Korea Concrete Institute
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• v.25 no.1
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• pp.107-114
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• 2013

In this study we experimentally evaluated an impact resistant performance of fiber reinforced concrete in the moment of explosion by high-velocity projectile with emulsion explosive. To assess the impact resistance, we conducted the impact test of high-velocity projectile which reaches an impact speed of 350 m/s and the experiment of contact exploding emulsion explosive. As a result, bending and tensile performance depending on type of PVA, PE fiber (polyvinyl alcohol fiber, polyethylene fiber) and steel fiber affects destruction of rear side in the form of spalling. Destroying the backside of the concrete compressive strength compared to suppress the bending and tensile performance is affected. In addition, the experiment shows that the destruction patterns of concrete specimen producted by high velocity impact and contact explosion are significantly similar. Therefore, it is possible to predict the destruction patterns of specimens in the situation of contact explosion by high-velocity projectile.