• Journal of Advanced Marine Engineering and Technology
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• 제39권3호
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• pp.312-317
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• 2015

선박은 충돌, 좌초 및 화재 등의 여러 가지 원인으로 승객 및 선원들이 긴급 피난을 해야 하는 경우가 많이 발생한다. 일반적으로 모든 피난에서 생존율을 높이기 위해서는 피난 시간의 단축이 아주 중요한 요소이나 선박의 복잡하고 좁은 구조적 특성은 신속한 피난에 장애 요소가 되고 있다. 특히, 선박은 그 구조상 동일한 규모의 화재 발생 시 타 화재에 비해 확산속도가 빨라 신속한 피난이 필요하다. 또한, 선박은 해상에서 운항하는 특성으로 좋지 않은 해상 상태에서는 승객 및 선원이 행동적 제약이 발생한다. 이 연구에서는 인명 안전 차원에서 선박 구조 변경이 승객 및 선원의 생존율 향상에 미치는 영향에 대해 이론적 접근 및 수치 시뮬레이션을 통해 분석하고자 한다. 분석 도구로는 3차원 화재분석 전용 프로그램인 FDS(Fire Dynamic Simulator)를 이용하였으며 화재 시 인명 안전에 영향을 가장 큰 영향을 미치는 온도 상승 및 가시거리 감소를 분석하였다. 그 결과 선박의 복도 폭 및 천장의 높이만 개선하여도 인명 안전에 상당한 도움이 되는 것으로 분석되었다.

• 한국전산구조공학회논문집
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• 제27권2호
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• pp.95-102
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• 2014

이 논문에서는 경계반력법을 이용한 비선형 지반-구조물 상호작용 해석을 위해 LS-DYNA나 MIDAS/Civil 등의 유한요소해석 프로그램과 연계하는 방법을 제시하였다. 경계반력법 적용시 유한요소프로그램에서 구조물과 지반은 선형 또는 비선형 유한요소를 이용하여 모델링하였다. 유한요소의 해석모델 외부의 무한영역으로 전달되는 탄성파를 최대한 흡수하기위해 유한요소 모델의 외측에 LS-DYNA의 경우에는 PML(Perfectly Matched Layer) 요소를, MIDAS/Civil의 경우에는 점성감쇠-스프링 요소를 적용하였다. 비선형 유한요소는 구조물영역에만 적용되는 것으로 가정하였다. 이 연구에서는 입사지진파에 의한 경계반력은 KIESSI-3D 프로그램을 이용하여 계산하였다. 선형 지반-구조물 상호작용 문제에 대해 일반적인 KIESSI-3D의 해석결과와 BRM해석결과를 비교하여 제시된 방법의 효율성을 제시하였다. 또한 수치적 비교를 통해 비선형 구조에 대해 보수적인 응답을 보이는 선형 SSI문제에 대하여 얻은 경계반력이 비선형 지반-구조물 상호작용해석에 효과적으로 적용 가능함을 알 수 있었다.

• 유통과학연구
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• 제14권4호
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• pp.67-79
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• 2016

Purpose - Over recent years, we have concerned about safety and quality on food products because of delivery complexity. The dependence of foreign food products escalate supply of products. And there are often negligent accident of marine and agricultural products. Therefore, the complexity increases the importance of safety on food and information quality for consumers. In spite of the interest augmentation of various interested parties, there is decrease in reliability and effectiveness, if it would be established without the right directivity. For the study, we tried to examine the first considerations the point of - view in service environment and information quality with accepting and diffusing the Traceability System. Then, we tried to verify the relationships between the factors of TS and the determinants of behavior decision. Next, we made efforts to find the mutual relationship among distributors, producers, consumers and the other prerequisite factors from the point of view in service environment and information quality in order to operate effectively the information perspective and system. Research design, data, and methodology - For the purpose of this study, the samples of consumers were targeted to Traceability System, and 661 people have been investigated. Through theoretical discussion of previous research, nine hypotheses were established, the influence of Continuous User Intention in TS. In order to test the hypotheses, a survey had conducted for 661 consumers as opinion leaders in their 20s-60s as data, and structural equation modeling was used. The difference analysis between Agricultural and Marine Products in TS; SPSS 22.0 and AMOS 22.0 were used for statistical analysis. Results - The major findings from this study were as follow; all factors of information quality excluding completeness and a social-impact had effects on the ease of use; all factors excluding understand ability in information quality and a social-impact had effects on the usefulness; completeness and social-impact had effects on perceived value; the ease of use had effects on usefulness and perceived value; usefulness had effects on perceived value and the intention of continuous use. From the results of different analysis, the CPLT(Completeness) factor has positive effects on Easy of USE and PV(Perceived Value) strongly in agricultural products. On the other hand, Social Duty has positive effects on Easy of Use strongly in marine products. Conclusion - In the age of information overflowing, TS will be a burden for users if it places too much emphasis upon accessibility. To accept and diffuse TS safely, therefore, Information System should be settled first into initial market formation. In addition, if TS elements are considered in conjunction with information factors and user environment, the acceptance and diffusion of TS would make synergy effect, even better. That is, this study contributes to the acceptance and diffusion of Traceability System. Accordingly, information quality will be settled into initial market formation. Also, social-impact element will be considered in conjunction with information quality's factors, and it will make synergy effect.

• 대한조선학회논문집
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• 제54권1호
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• pp.43-48
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• 2017

In recent years, the demand for ships and offshore platforms that can navigate and operate through the Arctic Ocean has been rapidly increasing due to global warming and large reservoirs of oil and natural gas in the area. Winterization design is one of the key issues to consider in the robust structural safety design and building of ships that operate in the Arctic and Sub-Arctic regions. However, international regulations for winterization design in Arctic condition regulated that only those ships and offshore platforms with a Polar Class designation and/or an alternative standard. In order to cope with the rising demand for operating in the Arctic region, existing and new Arctic vessels with a Polar Class designation are lacking to cover for adequate winterization design with HSE philosophy. Existing ships and offshore platform was not designed based on reliable data based on numerical and experiment studies. There are only designed as a performance and functional purposes. It is very important to obtain of reliable data and provide of design guidance of the anti-icing structures by taking the effects of low temperature into consideration. Therefore, the main objective of this paper reconsiders anti-icing design of aluminum helideck using the heating cable. To evaluate of reliable data and recommend of anti-icing design method, various types of analysis and methods can be applied in general. In the present study, finite element method carried out the thermal analysis with cold chamber testing for performance and capacity of heating cables.

• Structural Engineering and Mechanics
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• 제9권5호
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• pp.449-467
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• 2000

The natural frequencies and the corresponding mode shapes of a non-uniform beam carrying multiple point masses are determined by using the analytical-and-numerical-combined method. To confirm the reliability of the last approach, all the presented results are compared with those obtained from the existing literature or the conventional finite element method and close agreement is achieved. For a "uniform" beam, the natural frequencies and mode shapes of the "clamped-hinged" beam are exactly equal to those of the "hinged-clamped" beam so that one eigenvalue equation is available for two boundary conditions, but this is not true for a "non-uniform" beam. To improve this drawback, a simple transformation function ${\varphi}({\xi})=(e+{\xi}{\alpha})^2$ is presented. Where ${\xi}=x/L$ is the ratio of the axial coordinate x to the beam length L, ${\alpha}$ is a taper constant for the non-uniform beam, e=1.0 for "positive" taper and e=1.0+$|{\alpha}|$ for "negative" taper (where $|{\alpha}|$ is the absolute value of ${\alpha}$). Based on the last function, the eigenvalue equation for a non-uniform beam with "positive" taper (with increasingly varying stiffness) is also available for that with "negative" taper (with decreasingly varying stiffness) so that half of the effort may be saved. For the purpose of comparison, the eigenvalue equations for a positively-tapered beam with five types of boundary conditions are derived. Besides, a general expression for the "normal" mode shapes of the non-uniform beam is also presented.

• 해양환경안전학회지
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• 제11권2호
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• pp.77-82
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• 2005

지금까지 국내에서 제작된 요트는 선체의 재질이 FRP로 제작되어 왔으나 FRP는 환경오염 및 해양안전에 관한 법규 규제가 강화되고 있는 국제사회의 인식에 따라 중소형 조선소를 중심으로 강철 재료나 알루미늄 재료들 사용한 선박건조로 변화하고 있는 실정이다. 강선요트의 구조상 강선재료를 주로 사용함으로서 여러 가지 강도적인 측면에 대한 검토가 필요하지만, 소형선박이므로 종강도, 횡강도 부분은 규정에서의 허용 응력치에 안전율(Safe Factor)만을 주어서 설계를 하여도 충분히 안정된 구조를 이를 수가 있다. 그러나, 소형선박에서 가장 문제시되는 것은 국부강도(Local Strength)의 평가이다. 본 구조해석에서는 선수에 작용하는 슬래밍 동작하중 및 선수충격에 의한 선수부의 손상 여부와 선수부의 국부강도 만족 여부를 확인하고, 기관받침(Engine bed) 부분에서의 중량하중과 횡파하중에 대한 검토를 수행하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권3호
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• pp.262-268
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• 2014

본 연구는 2MW급 풍력 발전기용 고속커플링의 요구조건인 유연성과 절연성 및 과부하시 기능부품의 파손을 방지하기 위한 동력 차단기능을 만족하기 위한 구조설계와 검증에 관한 것이다. 커플링의 유연성과 절연기능은 강도와 유연성 및 절연성을 동시에 가지는 유리섬유강화플라스틱을 이용하여 설계하였으며 유한요소해석을 통하여 원소재 두께를 최적화하였다. 또한 이상 토크 발생시 동력전달을 차단하기 위한 토크리미터를 마찰차 형식으로 설계하였다. 시제품의 성능평가를 통하여 설계변수의 타당성을 검증하였다.

• Structural Engineering and Mechanics
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• 제85권2호
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• pp.197-206
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• 2023

The deterioration caused by chloride penetration and carbonation plays a significant role in a concrete structure in a marine environment. The chloride corrosion in some marine concrete structures is invisible but can be dangerous in a sudden collapse. Therefore, as a novelty, this research investigates the ability of a non-destructive damage detection method named the Power Spectral Density (PSD) to diagnose damages caused only by chloride ions in concrete structures. Furthermore, the accuracy of this method in estimating the amount of annual damage caused by chloride in various parts and positions exposed to seawater was investigated. For this purpose, the RC Arosa bridge in Spain, which connects the island to the mainland via seawater, was numerically modeled and analyzed. As the first step, each element's bridge position was calculated, along with the chloride corrosion percentage in the reinforcements. The next step predicted the existence, location, and timing of damage to the entire concrete part of the bridge based on the amount of rebar corrosion each year. The PSD method was used to monitor the annual loss of reinforcement cross-section area, changes in dynamic characteristics such as stiffness and mass, and each year of the bridge structure's life using sensitivity equations and the linear least squares algorithm. This study showed that using different approaches to the PSD method based on rebar chloride corrosion and assuming 10% errors in software analysis can help predict the location and almost exact amount of damage zones over time.

• 한국해양공학회지
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• 제34권5호
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• pp.316-324
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• 2020

This paper presents comparative studies of reliability analysis and meta-modeling using the sampling method of Monte Carlo simulation for the structure design of an automatic ocean salt collector (AOSC). The thickness sizing variables of structure members are considered as random variables. Probabilistic performance functions are selected from strength performances evaluated via the finite element analysis of an AOSC. The sampling methods used in the comparative studies are simple random sampling and Sobol sequences with varied numbers of sampling. Approximation methods such as the Kriging model is applied to the meta-model generation. Reliability performances such as the probability failure and distribution are compared based on the variation of the sampling method of Monte Carlo simulation. The meta-modeling accuracy is evaluated for the Kriging model generated from the Monte Carlo simulation and Sobol sequence results. It is discovered that the Sobol sequence method is applicable to not only to the reliability analysis for the structural design of marine equipment such as the AOSC, but also to Kriging meta-modeling owing to its high numerical efficiency.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2004년도 추계학술발표회
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• pp.129-135
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• 2004

선체구조 부재에는 이중저의 거더 및 늑판등에서 유공을 가진 판이 많이 사용되고 있고, 이는 중량 경감, 사람 및 화물의 이동, 배관 등의 목적으로, 보통은 강도상 큰 문제가 없는 부위에 위치하지만, 때로는 불가피하게 높은 응력이 작용하는 부위에 설치해야 한 경우도 있다. 이러한 판에 유공의 존재는 면내 하중에 의한 탄성좌굴강도 및 최종강도에 큰 영향을 주게 된다. 따라서, 유공판의 탄성좌굴강도 및 최종강도 평가는 선박의 초기 구조설계단계에서 구조부재 치수를 결정할 때 검토해야 할 중요한 설계기준 중의 한가지 이다. 그러므로, 유공판에 대한 합리적인 신뢰적인 탄성좌굴강도 및 최종강도 설계식이 필요시 되고 있다. 본 연구에서는 다양한 종횡비와 유공의 치수비 그리고 세장비의 영향을 고려하여 탄소성대변형 유한요소법을 근간으로 한 해석코드인 ANSYS를 사용하여 수치계산을 수행하였다.