• Architectural research
• /
• 제15권3호
• /
• pp.151-158
• /
• 2013

Offshore oil and gas process plants are exposed to hazardous accidents such as explosion and fire, so that the structural components should resist such accidental loads. Given the possibilities of thousands of different scenarios for the occurrence of an accidental hazard, the best way to predict a reasonable size of a specific accidental load would be the employment of a probabilistic approach. Having the fact that a specific procedure for probabilistic accidental hazard analysis has not yet been established especially for explosion and fire hazards, it is widely accepted that engineers usually take simple and conservative figures in assuming uncertainties inherent in the procedure, resulting either in underestimation or more likely in overestimation in the topside structural design for offshore plants. The variation in the results of a probabilistic approach is determined by the assumptions accepted in the procedures of explosion probability computation, explosion analysis, and structural analysis. A design overpressure load for a sample offshore plant is determined according to the proposed probabilistic approach in this study. CFD analysis results using a Flame Acceleration Simulator, FLACS_v9.1, are utilized to create an overpressure hazard curve. Moreover, the negative impulse and frequency contents of a blast wave are considerably influencing structural responses, but those are completely ignored in a widely used triangular form of blast wave. An idealistic blast wave profile deploying both negative and positive pulses is proposed in this study. A topside process module and piperack with blast wall are 3D FE modeled for structural analysis using LS-DYNA. Three different types of blast wave profiles are applied, two of typical triangular forms having different impulse and the proposed load profile. In conclusion, it is found that a typical triangular blast load leads to overestimation in structural design.

• 한국해양공학회지
• /
• 제25권3호
• /
• pp.1-10
• /
• 2011

This paper estimates the residual longitudinal strength of a damaged double hull VLCC (Very Large Crude Carrier) under combined vertical and horizontal bending moments using Smith's method. The damage estimated in this study occurred due to collision or grounding accidents. The effects of the randomness of the yield stress, plate thickness, extent of damage, and the combination of these three parameters on the ultimate hull girder strength were investigated. Random variables were generated by a Monte Carlo simulation and applied to the double hull VLCC described by the ISSC (International Ship and Offshore Structures Congress) 2000 report.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 1995년도 가을 학술발표회 논문집
• /
• pp.234-241
• /
• 1995

Offshore structures are exposed to higher probability of collision with ship because of their limited mobility. In general, the consequence of the collision is reported to be relatively small and it is desirable to consider minor collisions in the design stage. It is important to have a comprehensive understanding of the dynamic responses of a tubular, their main member, under collision to design offshore structure against possible accidents. It is needed to estimate the probable extent of damage of a tubular, depth of dent, affected by the time history of impact load in ender to design a tubular strong enough for collision. In this paper, dynamic behaviors of a tubular due to the lateral impact are investigated through the numerical simulations with hydrocode DYNA3D, a three dimensional elasto-plastic large deformation impact contact problem analyzing program.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2011년도 춘계학술대회
• /
• pp.382-384
• /
• 2011

해양구조물에서 헬리콥터는 주로 인력을 수송하지만 비상상황 발생 시 탈출수단 또는 수색 구조수단으로 이용되고 있으며, 자원을 찾아 깊고 먼 바다로 이동하는 해양구조물의 인력을 수송하기에 헬리콥터는 가장 빠르고 안전한 수단이지만 해상으로 추락과 같은 사고는 발생할 수 있다. 헬리콥터의 수중 추락 시 생존율을 높이기 위하여 헬리콥터 자체의 안전설비와 운용방식을 발전시키고 탑승자들에게 사전 브리핑을 실시하고 수중탈출 훈련을 실시하였다. 본 논문에서는 헬리콥터의 해상 추락 사고를 분석하고 탑승자의 생존율을 높이기 위한 헬리콥터의 안전설비 및 운용방식과 수중 추락 시 탑승자의 탈출요령에 대한 훈련에 대하여 소개한다.

• 한국산업보건학회지
• /
• 제26권4호
• /
• pp.436-444
• /
• 2016

Objectives: Despite recent efforts to prevent suffocation disasters, a number of confined space accidents still happen and each year deaths continue to occur. There have been insufficient studies on the dangers of various potential disaster sites, such as manholes, septic tanks, reactors, and other tanks according to type, characteristics, task-specific disasters, equipment specific disasters, etc. The purpose of this study was to analyze recent suffocation disasters based on place and properties. Methods: In this study, we analyzed confined space accident cases from 2005 to 2015 in Korea and grouped them by type, size, monthly occurrence, continuous service period, accident location, person-specific group, age, employment, structural work and subcontracting work. We studied examples of accidents developed in other countries. Results: (1) We reviewed confined-space accident statistics, compared legal standards and analyzed cases of suffocation accidents in the United States and Japan. (2) Using a case study report from the Korea Occupational Safety & Health Agency, we specified confined-space accident statistics based on place, person-specific group, age, employment, structural work and subcontracting work. As a result we generated some precautions about confined-space accidents for the prevention of such accidents. Conclusions: Conclusions: Statistical analysis of recent suffocation disaster cases was performed to establish improvement measures, compare practices from developed countries, and develop precautionary measures accordingly. In this study, we presented the causes of disaster that occur in a confined space and proposed related preventive measures.

• 한국항해항만학회지
• /
• 제41권5호
• /
• pp.303-318
• /
• 2017

In the shipping industry, it is well known that around 80 % or more of all marine accidents are caused fully or at least in part by human error. In this regard, the International Maritime Organization (IMO) stated that the study of human factors would be important for improving maritime safety. Consequently, the IMO adopted the Casualty Investigation Code, including guidelines to assist investigators in the implementation of the Code, to prevent similar accidents occurring again in the future. In this paper, a process of the human factors investigation is proposed to provide investigators with a guide for determining the occurrence sequence of marine accidents, to identify and classify human error-inducing underlying factors, and to develop safety actions that can manage the risk of marine accidents. Also, an application of these investigation procedures to a collision accident is provided as a case study This is done to verify the applicability of the proposed human factors investigation procedures. The proposed human factors investigation process provides a systematic approach and consists of 3 steps: 'Step 1: collect data & determine occurrence sequence' using the SHEL model and the cognitive process model; 'Step 2: identify and classify underlying human factors' using the Maritime-Human Factor Analysis and Classification System (M-HFACS) model; and 'Step 3: develop safety actions,' using the causal chains. The case study shows that the proposed human factors investigation process is capable of identifying the underlying factors and indeveloping safety actions to prevent similar accidents from occurring.

• 한국해안해양공학회:학술대회논문집
• /
• 한국해안해양공학회 1998년도 정기학술강연회 발표논문 초록집 Annual Meeting of Korean Society of Coastal and Ocean Engineers
• /
• pp.40-44
• /
• 1998

Since oil spills discharged by offshore oil production platforms, ship accidents etc., cause many environmental problems, forecasts of drift and spreading of the spilled oil are requested as a basis for oil spill combat management. The numerical approach has been thought as the most effective methods of such forecast. In general, the oil spill model takes into account the trajectory and fate of oil, including drifting, spreading, evaporation, dispersion, emulsification, shoreline standing, and so on. (omitted)

• 예술인문사회 융합 멀티미디어 논문지
• /
• 제8권5호
• /
• pp.417-425
• /
• 2018

본 논문에서는 조선해양 작업장에서 발생하는 중대재해를 줄이고 체계적인 안전관리를 위하여 ETA(event tree analysis)기반 시나리오 도출 및 ICT 기술접목을 통한 안전관리 구축방안을 제안한다. 안전보건공단과 (구)국민안전처의 통계결과 조선해양 관련 중대재해 중 가장 많이 발생하는 사고유형은 떨어짐이고, 주요사고원인은 안전대 미착용 및 안전대 고리 미체결이다. 이 문제를 해결하기 위해 ETA기반의 시나리오를 작성하여 안전사항에 따른 결과를 도출하고 이 결과를 바탕으로 사고예방을 위한 ICT 기술접목으로 해결방안을 제시한다. ETA 기반 시나리오 도출 및 ICT 기술접목을 통해 제안한 해결방안으로는 안전대 및 안전모 착용여부 감지시스템, 안전대 고리 체결여부 감지시스템, 안전거리 측정을 위한 걸이설비 측정시스템이다. 안전사항별 시스템을 통해 작업자의 떨어짐 위험을 줄여 사망확률을 낮출 수 있다. 제안한 방안을 통해 사고를 예방함으로써 조선해양 분야의 중대재해를 줄이고 체계적인 안전관리를 도모한다.

• 대한조선학회논문집
• /
• 제56권3호
• /
• pp.251-262
• /
• 2019

This paper is about design concept and simplified analysis method against dropped object events. The ships and offshore structures are exposed to various types of dropped object accidents such as laydown area struck by drill collar and topside deck hit by food container during their lifetime. Mitigation can be accomplished by proper facility layout and designing structures to safely absorb energy from accidental loads. It shall be designed to avoid loss of life, environmental pollution and loss of assets. Impact loads can lead to structural global collapse of the main structure or punching of a local barrier type structure with potential to escalate directly or indirectly to a global collapse of the structure. This study provides the background information on the issue of dropped object of the shipyard and also focuses on structural assessment of the local individual component such as deck plate, stiffener and web/girder by using simplified analysis method. The results of the simplified analysis method were compared with numerical results using non-linear finite element simulation.

• 한국해양공학회지
• /
• 제27권5호
• /
• pp.105-114
• /
• 2013

Lots of orders of special vessels and offshore plants for developing the resources in deepwater have been increased in recent. Because the most of accidents on those structures are caused by fire and explosion, many researchers have been investigated quantitatively to predict the cause and effect of fire and explosion based on both experiments and numerical simulations. The first step of the evaluation procedures leading to fire and explosion is to predict the dispersion of flammable or toxic material, in which the released material mixes with surrounding air and be diluted. In particular turbulent mixing, but density differences due to molecular weight or temperature as well as diffusion will contribute to the mixing. In the present paper, the numerical simulation of hydrogen dispersion inside a simple-shaped offshore structure was performed using a commercial CFD program, ANSYS-CFX. The simulated results for concentration of released hydrogen are compared to those of experiment and other simulation in Jordan et al.(2007). As a result, it is seen that the present simulation results are closer to the experiments than other simulation ones. Also it seems that the hydrogen dispersion is closely related to turbulent mixing and the selection of the turbulence model properly is significantly of importance to the reproduction of dispersion phenomena.