• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3A
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• pp.323-330
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• 2008

The ship collision analysis of steel pile group as protection system of bridge in navigable waterways was performed to analyze the structural characteristics of protective structure during ship collision. The analysis encompassed finite element modeling of ship and pile, modeling of material non-linearity, hard impact analysis, displacement-based analysis and soft impact analysis for collision scenarios. Through the analysis of hard impact with a rigid wall, impact load for each collision type of ship bow was estimated. In the displacement-based analysis the estimate of energy which protection system can absorb within its maximum horizontal clearance so as to secure bridge pier from vessel contact during collision was performed. Soft impact analysis for various collision scenarios was conducted and the collision behaviors of vessel and pile-supported protection system were reviewed for the design of protection system. The understanding of the energy dissipation mechanism of pile supported structure and colliding vessel would give us the optimized design of protective structure.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.433-436
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• 2010

본 논문에서는 파일형 선박충돌 방호공에 선박이 충돌하였을 때 방호공의 거동을 해석하였다. 방호공의 구조는 상부슬래브, RCP 말뚝 및 이를 지지하는 지반은 비선형 지반스프링으로 모델링 하였다. 상부슬래브 8절점요소로 모델링 하였으며 철근과 콘크리트로 구성되어있다. RCP 말뚝은 철근망과 충진콘크리트로 구성되어있으며 충돌 시 파괴거동을 표현할 수 있는 Damaged Plasticity로 모델을 사용하였고 Shell 요소로 모델링 하였다. 선박충돌 시 선박의 강성에 따른 거동 특성을 파악하기 위해 선박을 강체모델과 실제모델에 대한 해석을 수행하였다. 선박과 교량의 충돌은 정면충돌로 고려하였으며, 충돌속도는 3.3m/sec로 가정하였다. 선박과 방호공과의 충돌 해석은 비선형 해석 프로그램인 ABAQUS/Explicit을 이용하여 수행하였으며, 이를 통하여 선박 충돌 시 방호공의 에너지 거동을 분석하였다. 해석결과 선박의 강성이 커질수록 슬래브의 변형 및 소산 에너지량이 커지는 것을 확인할 수 있었다.

• Journal of Ocean Engineering and Technology
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• v.2 no.1
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• pp.90-94
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• 1988

본 논문은 반 잠수식 시추선과 선박과의 충돌해석에의 정적 압축법의 응용에 대해 다루었다. 선박이 시추선의 취약 부재에 충돌하는 경우를 가정하였으며 이 취약한 부재의 충돌에너지 흡수능력을 상세 해석 없이 추출하는 방법으로, 관련된 구조물 전체 강성 매트릭스를 부재의 양단에 정적 압축을 시켜 양단 유연도를 추출한 뒤 이 유연도를 양단에 가진 원통형 부재를 해석함으로써 외력-변형 관계를 얻을수 있었다. 충돌에너지 양은 외력-변형 선도를 적분함으로써 얻을 수 있다. 새로운 방법에 의한 결과를 3차원 수치해석 방법과 강체 프라스틱 방법에 의해서 얻어진 결과와 상호 비교하였으며, 이 새로운 방법이 해양구조물 충돌해석이 매우 효과적으로 응용될 수 있음을 알게 되었다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.4D
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• pp.539-546
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• 2011

Traffic accident collision interpretation is composed of various shapes, and speed variations working to the vehicle during collision are utilized as a very important factor in evaluating collision degrees between vehicles and safety of passengers who got in the vehicle. So, methods of interpreting results on speed variations utilizing simulation programs on the collision interpretation become necessary. By the way, reliability evaluation on each program is being required because various collision interpretations simulations are spread widely. This study utilized collision interpretation programs such as EDSMAC and PC-CRASH adopting completely different physical approaches, and then carried out collision experiments of one-dimensional front and two-dimensional right angle while changing values of a lot of collision factors such as vehicle's weight, center of gravity, rolling resistance, stiffness coefficient, and braking forces among early input conditions. Also, the study recognized effects of collision factors to speed variations as output results during crashing. As a result of this research, two simulation programs showed same speed variations together on the vehicle's weight, center of gravity, and braking forces. Stiffness coefficient of the vehicle reacted to EDSMAC only, and rolling resistance coefficient did not affect any particular influences on speed variations. However, there appeared a bit comparative differences from the speed variation's values, and this is interpreted as responding outcomes by applying fixed properties values to each simulation program plainly. Therefore, reliability on analysis of traffic accident collisions shall be improved by doing speed analysis after taking the fixed value of simulation programs into consideration.

• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.4
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• pp.13-21
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• 2011

Seismic structure pounding between adjacent superstructures may induce the destruction of pier and bridge superstructures and cause local damage that leads to the collapse of the whole bridge system. The pounding problem is related to the expansion of joints, gap distance and seismic response of the abutments. In this research, methods of the contact element approach, the linear spring model, the Kelvin-Voigt model and the Hertz model were studied to analyse the pounding characteristics. The shaking table test for a model specimen such as a bridge superstructure with elastomeric bearings was performed to evaluate the contact element approach methods. Relationships between the time history response from the numerical analysis results and the measured response from the shaking table test are compared. The experimental results were not well matched with the numerical analysis results using the existing pounding stiffness models. Therefore, in this study, coefficients are proposed to calculate the appropriate pounding stiffness ratio.

• Journal of Korean Society of Transportation
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• v.32 no.5
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• pp.503-512
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• 2014

In this paper, various tire blow-out force experiment data were collected and analyzed to obtain approximate values of related coefficients such as rolling resistance, self-aligning torque, cornering stiffness, and radial stiffness for the analysis of the motion of vehicles with tire blow-outs. These coefficients related to tire blow-outs were input into a vehicle accident analysis program to simulate and examine the effects of tire blow-outs. Various configurations and velocities of vehicle collisions without tire blow-outs were also used as reference to establish collision events of vehicle collisions with tire blow-outs. For the events, the simulation analysis was performed and collision characteristics were obtained. Consideration of tire blow-outs or damages suggested in this study will greatly contribute to more reliable vehicle accident reconstructions.

• Journal of the korean Society of Automotive Engineers
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• v.18 no.4
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• pp.27-35
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• 1996

측면 충돌시 승객의 안전확보를 위한 미국 및 유럽의 법규 제정 과정과 배경을 살펴보고 이 두 법규를 비교하였다. 또한 이들 신 법규에 대응한 신차 개발을 위하여 컴퓨터 시뮬레이션과 같은 해석 기법을 이용시 개발 비용의 절감은 물론 개발기간도 단출할 수 있음을 보이고 미국 법규에 따른 해석 사례를 소개하였다. 정적 도어 구조 강성 해석의 경우 시험값과 평균적으로 10% 내의 오차를 보여주었다. 또한 동적 측면 충돌 해석 결과는 시험값과 비교하여 이동 대차 중심, 우측 B-필라하단 및 운전석 도어 중심에서의 Y-방향 속도의 경우 평균적으로 약 5% 차이를 보였으며 운전석 더미의 상해치는 골반 가속도의 경우 약 30%, 흉부 상해치의 경우 약 4%차이를 보여주었다. 이러한 해석 기술의 발달은 해석 결과와 시험결과 사이의 차이를 더욱 줄일 것으로 기대되며 이를 효과적으로 이용시 시작차의 제작비 및 시험비 절감 및 개발기간 단축을 가져와 자동차 설계분야의 국제경쟁력을 높이는 중요한 역할을 할 것으로 기대된다.

• Composites Research
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• v.24 no.5
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• pp.9-16
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• 2011

This paper describes the crashworthiness evaluation and performance improvement of tilting train made of sandwich composites. The applied sandwich composite of carbody structure was composed of aluminum honeycomb core and glass/epoxy & carbon/epoxy laminate composite facesheet. Crashworthiness analysis of tilting train was carried out using explicit finite element analysis code LS-DYNA 3D. The 3D finite element model and 1D equivalent model were applied to save the finite element modeling and calculation time for crash analysis. The crash conditions of tilting train were conducted according to four crash scenarios of the Korean railway safety law. It found that the crashworthiness analysis results were satisfied with the performance requirements except the crash scenario-2. In order to meet the crashworthiness requirements for crash scenario-2, the stiffness reinforcement for the laminate composite cover and metal frames of cabmask structure was proposed. Consequentially, it has satisfied the requirement for crash scenario-2.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.3
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• pp.75-86
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• 1999

An analysis model is developed to evaluate the dynamic responses of a bridge system under seismic excitations, in which pounding actions between girders are considered in addition to other phenomena such as nonlinear pier motion, rotational and translational motions of foundations. The model also considers the abutment and restrainers connecting adjacent girders to prevent the unseating failures. Using the developed model, the longitudinal dynamic behaviors of a bridge system are examined for various peak ground accelerations, and the effects of the applied restrainers are investigated. It is found that the restrainers reduce the relative displacement with the shorter clearance length as well as the higher stiffness of the restrainers for moderate excitations. However, in the region with strong excitations the restrainers may yield due to the large relative displacement. Therefore, the extension of support length in addition to restrainers may need to prevent the unseating failure more effectively.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.2
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• pp.93-100
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• 2022

The collision behaviors of the tripod and jacket structures, which are considered as support structures for offshore wind towers at the Southwest sea of Korea, were compared by nonlinear dynamic analysis. These structures, designed for the 3 MW capacity of the wind towers, were modeled using shell elements with nonlinear behaviors, and the tower structure including the nacelle, was modeled by beam and mass elements with elastic materials. The mass of the tripod structure was approximately 1.66 times that of the jacket structure. A barge and commercial ship were modeled as the collision vessel. To consider the tidal conditions in the region, the collision levels were varied from -3.5 m to 3.5 m of the mean sea level. In addition, the collision behaviors were evaluated as increasing the minimum collision energy at the collision speed (=2.6 m/s) of each vessel by four times, respectively. Accordingly, the plastic energy dissipation ratios of the vessel were increased as the stiffness of collision region. The deformations in the wind tower occurred from vibration to collapse of conditions. The tripod structure demonstrated more collision resistance than the jacket structure. This is considered to be due to the concentrated centralized rigidity and amount of steel utilized.