• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.2
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• pp.161-167
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• 2016

In this study, the effect of wall curvature and post-tension force on impact resistance is evaluated by numerical analysis method. A total of twelve cases with two parameters such as wall shape of flat and curved, and consideration of post-tensioning force were included in this study. A 3D detailed finite element model of commercial passenger plane engine is utilized as projectile. The depths of penetration and central displacement calculated from the numerical simulations were compared and analysed. As the results of the numerical simulations of this study, penetration depth was reduced approximately 60~80% due to the application of post-tension force, but the decrease of maximum central displacement was not remarkable. Also, the effect of curvature was relatively insignificant.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1B
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• pp.17-26
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• 2005

RFID(Radio Frequency IDentification) is a technology that automatically identifies objects attached with electronic tags by using radio wave. For the implementation of an RFID system, an anti-collision algorithm is required to identify several tags within the RFID reader's range. Few researches report the performance trade-off among anti-collision algorithms in terms of the communications traffic between the reader and tags, the identification speed, and so on. In this paper, we analyze both tree based memoryless algorithms and slot aloha based algorithms that comprise of almost every class of existing anti-collision algorithms. To compare the performance, we evaluated each class of anti-collision algorithms with respect to low-cost RFID system with 96-bit EPC(Electronic Product Code). The results show that the collision tracking tree algorithm outperforms current tree based and aloha based algorithms by at least 2 times to 50 times.

• Composites Research
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• v.21 no.5
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• pp.15-22
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• 2008

This paper describes the results of structural integrity and crashworthiness of Automatic Guideway Transit(AGT) vehicle made of sandwich composites. The applied sandwich composite of vehicle structure was composed of aluminum honeycomb core and WR580/NF4000 glass fabric/epoxy laminate composite facesheet. Material testing was conducted to determine the input parameters for the composite facesheet model, and the effective equivalent damage model fer the orthotropic honeycomb core material. The finite element analysis using ANSYS v11.0 was dont to evaluate structural integrity of AGT vehicle according to JIS E 7105 and ASCE 21-98. Crashworthiness analysis was carried out using explicit finite element code LS-DYNA3D with the lapse of time. The crash condition was frontal accident with speed of 10km/h at rigid wall. The results showed that the structural integrity and crashworthiness of AGT vehicle were proven under the specified loading and crash conditions. Also, the modified Chang-Chang failure criterion was recommended to evaluate the failure modes of composite structures after crashworthiness event.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.1753-1763
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• 2013

In the design phase of sea-crossing bridge projects, ship collision problem is mostly participated in decision of substructure section and it would be performed by risk assessment and impact simulations. Ship collision risk is assessed by probability model which is similar to method II of Guide Specification and Commentary for Vessel Collision Design of Highway Bridge(AASHTO, 2009). However, several factors used in the applicable code are limited to inland waterways or have many local characteristics. Accordingly, it should be needed judgement of engineer or referred to related criteria, research finding. In this study risk assessment for In-cheon bridge and review of existing substructure's impact risk and resistance capacity are performed using the 2010's ship passage data. And then consideration regarding to presumption and applied instance of factors needed for risk assessment and related research findings are performed on the basis of AASHTO Guide's Method. As a result of study, adequate variable region of factors needed for risk assessment is defined and sensitivity analysis for appropriate region is performed. Consequently, factors that should be applied carefully or needed for direct analysis of local data are confirmed. This research could be fundamental material to risk assessment related to design for sea-crossing bridge taken into account ship collision.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.2
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• pp.169-176
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• 2015

The protection facilities against the collision of the vehicle should be considered in the design of the bridge by the regulations, but there is no regulation against the collision of the vehicle in the design of the column of underpass. Impact analysis for the column of underpass was performed in order to evaluate the damage of the structure by the collision of the vehicle. Impact analysis was performed according to the various parameters such as material properties of the structure and types and velocities of the vehicle. From the numerical results, the structural damage for the column of underpass by the collision of the vehicle was evaluated and considerations in the design for a column of underpass against the collision of the vehicle were examined.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.8-14
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• 2019

Bird-strike is one of the most important design factors for safety in the aviation industry. Bird-strikes have been the cause of significant damage to aircraft and rotorcraft structures and the loss of life. This study used DYTRAN software to simulate the transient response of an Euler-Lagrangian composite helicopter blade that has been impacted by a bird. The Arbitrary Lagrangian Eulerian (ALE) method and a suitable equation of state were applied to model the bird. ALE was applied to the bird-strike analysis due to the large difference between the properties of the blade and bird. The debris of the bird was assumed to be a fluid and applied as Euler elements after the collision. Through the analysis of bird impacts, the leading-edge of the rotor blade (50.8 mm) was used to identify a positive margin of 1.18 based on the TSAI-FILL criteria. The results are assessed to be sufficiently reliable and may be evaluated to replace tests with various analysis conditions. The structural stability of the rotor blade could be assessed by applying various load conditions and different modeling methods in the future.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.822-825
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• 2007

RFID(Radio Frequency Identification) 시스템에서 다수의 리더가 동시에 동일한 태그의 인식을 시도하는 경우, 태그는 다수의 리더가 요청한 내용을 처리할 수 없기 때문에 리더 충돌이 발생하게 된다. 이러한 리더 간 간섭에 의한 충돌은 RFID 시스템의 태그 인식 효율 및 인식 속도의 저하 등에 대한 주요 요인으로 작용하기 때문에 이를 방지할 수 있는 효과적인 리더 충돌 방지 알고리즘이 요구된다. 이에 본 논문에서는 리더 충돌이 발생한 경우, 관리 리더(Master Reader)와 보조 리더 그룹(Assistant Reader Group)간의 계층적인 구조를 형성하고, 관리 리더를 통해 하위 리더 그룹을 관리하여 리더 충돌을 방지하는 리더 충돌 방지 알고리즘을 제안한다. 또한, 모의실험을 통해 제안하는 알고리즘의 성능을 분석하고 평가하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.731-734
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• 2011

본 연구에서는 강재로 구성된 선박충돌방호공의 최대방호능력을 산정하기 위하여 선박과 충돌방호공을 모델링하고 충돌거동을 해석하였다. 이러한 비선형충돌해석은 매우 큰 요소망과 고도의 비선형성을 려해야하기 때문에 이의 해석비용이 일반적인 해석에 비하여 매우 크므로 해석의 경제성을 확보하기 의사정적해석방법을 이용하여 해석을 수행하였다. 이 과정에서 효율적인 해석을 위한 수치 해석기법이 추가되었다. 해석결과 얻어진 선박과 방호공의 에너지소산곡선을 바탕으로 충돌선박이 교량하부구조에 도달하는 시점을 추정하고 이를 바탕으로 대상선박의 최대충돌속도를 산정하였다.

• Journal of Korean Society of Transportation
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• v.26 no.2
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• pp.7-15
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• 2008

New Car Assessment Program(NCAP) provides consumers with vehicle safety information, primarily front and side crash rating results, and more recently rollover ratings, to aid consumers in their vehicle purchase decisions. NCAP is a system to improve driver and passenger safety by providing market incentives for vehicle manufacturers to voluntarily design their vehicles to better protect drivers and passengers in a crash and be less susceptible to rollover, rather than by regulatory directives. NCAP have been performed since 1999 in Korea by the government in order to reduce fatalities and injuries caused by traffic accidents. Although as the number of vehicles models increases, more vehicle models are required to be test and NCAP is evaluated as a valuable system for vehicle safety, the expansion of the system is slow. It looks like that the benefit of NCAP quantitatively was not verified. In this study, based on the idea that the benefit of the NCAP is defined as the decrease of traffic accident severity by improving vehicle safety, a methodology to analyze the effectiveness of NCAP quantitatively in terms of traffic safety was developed. According to the developed methodology, the reduced numbers of fatalities and injuries were 1.51 and 466 in 2005.

• 한국ITS학회:학술대회논문집
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• 2004.11a
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• pp.294-299
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• 2004