• 대한안전경영과학회지
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• 제23권4호
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• pp.67-72
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• 2021

To ensure the safety and functionality of a railroad bridge, maintaining the integrity of the bridge via continuous structural health monitoring is important. However, most structural integrity monitoring methods proposed to date are based on modal responses which require the extracting process and have limited availability. In this paper, the applicability of the existing damage identification method based on free-vibration reponses to time-domain deflection shapes due to moving train load is investigated. Since the proposed method directly utilizes the time-domain responses of the structure due to the moving vehicles, the extracting process for modal responses can be avoided, and the applicability of structural health evaluation can be enhanced. The feasibility of the presented method is verified via a numerical example of a simple plate girder bridge.

• 해양환경안전학회지
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• 제4권2호
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• pp.1-12
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• 1998

This paper descirbes a series of numberical simulations of grounding accidents of four 40,000 DWT Conventional and Advanced Double Hull tanker bottom structures using LS/DYNA3D. The overall objective of this study is no understand the structural failure and energy absorbing mechanisms during grounding events for candidate double hull tanker bottom structures, which lead to the initiation of inner shell rupture and cause the kinetic energy dissipation to bring the ship to a stop. These nuberical simulations of the grounding events will contribute to future improvements in tanker safety at the design stage.

• 한국안전학회지
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• 제25권1호
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• pp.62-64
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• 2010

Since 1990 in South Korea, the considerable concern for the safety of construction sights has been increased due to serious accidents. There have been numerous big improvements in preventing the accidents by strengthening legal enforcement and by continuing to emphasize the safety management. Further, the safety standards and criteria for temporary constructional work have been enacted and established in order to maintain safe work environments in temporary construction and structure settings. However, the death rate from fall accidents is still high in the temporary constructional and structural settings in comparison to other work places in construction. According to the analysis of accidents in the field of construction between 2000 and 2007, the death rate from fall accidents in the temporary constructional settings was highest. In addition, there have been more fall accidents in the work setting by small or medium construction enterprises rather than large enterprises due to the relative lack of the safety management. Thus, in this study, the analysis of the causes of fall accidents in the temporary constructional and structural settings between 2000 and 2007 was conducted. Moreover, a survey study was carried out in order to investigate further causes based on the analysis. Finally, this study was also conducted in order to provide basic information and knowledge about the prevention of future accidents.

• 한국가스학회지
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• 제26권5호
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• pp.10-15
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• 2022

현재 정부 주관으로 가스 AMI(Advanced Metering Infrastructure) 계량기의 실증작업과 더불어 일부 도시가스사에서는 자체적으로 가스 AMI 계량기 실증사업을 한창 진행하고 있다. AMI 계량기 설치를 통해 원격검침, 사용자의 가스 안전 확보 등 여러 긍정적인 요소가 있지만 이에 반해 배터리 방전, 비싼 가격, 원격 검침 데이터의 신뢰성 저하 등 여러 문제점들 또한 내포하고 있다. 여러 문제점 중 본 연구에서는 가스 AMI 계량기의 보급 확대에 따른 구조적 안전성 문제와 가스 누설로 인한 잠재적 위험성을 선제적으로 제거함으로써 중대 시민재해 예방과 함께 가스 AMI 계량기의 개선사항을 다각적으로 모색하였고, 본 연구가 향후 정부의 가스 AMI 선진화 정책의 지속적 추진하는데 있어 기여할 것을 기대해 본다.

• 한국산학기술학회논문지
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• 제21권7호
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• pp.638-644
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• 2020

본 연구는 항공기 하중에 따라 발생하는 균열을 가정하여 항공기 취약 구조의 수명을 분석하고 구조 보강 개선을 수행하였다. 항공기 구조의 선제적 수명 예측 및 수명 관리를 통해 구조 건전성 및 안전성을 확보하였다. 특히, 항공기 구조물 취약부위의 수명 분석을 통해 운용 하중의 영향이 큰 Bulkhead의 개선이 필요한 3부위를 선정하였다. 분석 대상 항공기의 균열크기 검사능력은 0.03inch 수준과 비교하여 임계균열크기는 취약 3부위 중 최하인 0.032inch이다. 상대적으로 검사능력 대비 임계균열크기가 매우 적어 항공기 안전을 위해 개선이 필요하다. 그리고 피로수명 해석 결과 항공기 요구 수명인 15000 운용시간 이상 대비 취약 3부위 중 최하인 약 1450 운용시간은 항공기 초기검사 및 재검사 시간의 반복 횟수를 증가시켜 비용 및 인력의 소요를 발생시킨다. 결국, 식별된 취약 3부위의 구조 보강을 통해 형상을 개선하였다. 발생 균열에 대한 구조 내성의 증가를 통해 최하의 임계균열크기가 0.13inch로 확보되어 항공기 안전성이 증가하였다. 항공기 운용 중 발생하는 균열에 대한 최하의 구조 피로수명은 >25000 운용시간으로서 요구 수명 이상으로 분석되어 균열 및 파단에 의해 발생하는 수리비용과 과도한 보강범위 보다 최적화된 개선을 수행하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제14권5호
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• pp.169-178
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• 2010

해체공사는 건설행위에 의해 건립된 건축물의 수명이 평균 22년 이상 경과한 후에 시행되는 후행 건설공종이다. 90년대 이후 해체대상물이 고층화, 대형화됨에 따라 그에 대한 중장기적인 대비가 없었으며, 해체산업 관련 제도나 법 등이 체계적으로 마련되어 있지 않았다. 본 연구에서는 국내 해체공사 안전관리 관련법의 개선방안을 마련하고자 3가지 법령 개선(안)을 제안하였으며 그 내용은 다음과 같다. 첫째, 건설기술관리법의 안전관리계획 수립에서 해체공사 대상의 기준에 대하여 방안을 제시하였다. 둘째, 산업안전보건법의 해체공사표준안전작업지침의 문제점을 보완한 개선방안을 마련하였으며, 셋째, 건설기술관리법의 안전관리계획과 산업안전 보건법의 유해 위험방지계획의 중복성에 대한 통합화 방안을 제시하였다.

• 한국산업안전학회:학술대회논문집
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• 한국안전학회 2003년도 춘계 학술논문발표회 논문집
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• pp.508-513
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• 2003

The objective of this paper is to investigate the lining board's capacity by using the static loading test and fatigue test. Specimens that constitute the H & Channel type lining board are adopted. The test is to inspect the possibility of retrofit and efficiency, which is required to upgrade the structure's capacity and to examine the effects of the improvements of specimen by using structural analysis, stress analysis, static loading test and fatigue test, respectively. The accumulated test results of stress condition and deflection by bending will be used to analyze the relation between the cause of fatigue crack occurrence and the behavior of both structure system and the steel.

• Smart Structures and Systems
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• 제22권2호
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• pp.193-200
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• 2018

From the viewpoint of engineering applications, the prediction of the failure of bogies plays an important role in preventing the occurrence of fatigue. Fatigue is a complex phenomenon affected by many uncertainties (such as load, environment, geometrical and material properties, and so on). The key to predict fatigue damage accurately is how to quantify these uncertainties. A Bayesian model is used to account for the uncertainty of various sources when predicting fatigue damage of structural components. In spite of improvements in the design of fatigue-sensitive structures, periodic non-destructive inspections are required for components. With the help of modern nondestructive inspection techniques, the fatigue flaws can be detected for bogie structures, and fatigue reliability can be updated by using Bayesian theorem with inspection data. A practical fatigue analysis of welded bogies is utilized to testify the effectiveness of the proposed methods.

• 한국해양공학회지
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• 제24권2호
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• pp.25-33
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• 2010

Collision between vessels may lead to structural damage and penetration of hulls. The structural damage of a hull may eventually bring about global collapse of the hull girder and outflow of oil, which would contaminate seawater. Therefore, various regulations require the strength of a vessel after collision to satisfy given criteria, and owners usually request collision analyses to confirm the structural safety of their vessels. In the process of designing a vessel to satisfy the collision strength criteria, the strength has been assessed mostly by conducting collision analyses using numerical techniques, such as dynamic, non-linear, finite-element analysis. Design is an inherently iterative process during which many changes are necessary due to the endless needs for reinforcement and modification. Numerical techniques are not adequate for coping with a situation in which collision analysis is frequently required to provide the revised results that reflect the repetitive changes in designs. Numerical techniques require a lot of time and money to conduct in spite of recent improvements in computing power and in the productivity of modeling tools. Therefore, in this paper, an analytical technique is introduced and a collision problem is idealized and simplified using reasonable assumptions based on appropriate background. The technique was applied to an example of an actual FPSO and verified by comparing the results with results from the numerical technique. A good correlation was apparent between the results of the analytical and numerical techniques.

• Wind and Structures
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• 제12권6호
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• pp.479-504
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• 2009

Structural health monitoring (SHM) systems have been recently embraced in long span cable-supported bridges, in which buffeting-induced stress monitoring is one of the tasks to ensure the safety of the bridge under strong winds. In line with this task, this paper presents a SHM-oriented finite element model (FEM) for the Tsing Ma suspension bridge in Hong Kong so that stresses/strains in important bridge components can be directly computed and compared with measured ones. A numerical procedure for buffeting induced stress analysis of the bridge based on the established FEM is then presented. Significant improvements of the present procedure are that the effects of the spatial distribution of both buffeting forces and self-excited forces on the bridge deck structure are taken into account and the local structural behaviour linked to strain/stress, which is prone to cause local damage, are estimated directly. The field measurement data including wind, acceleration and stress recorded by the wind and structural health monitoring system (WASHMS) installed on the bridge during Typhoon York are analyzed and compared with the numerical results. The results show that the proposed procedure has advantages over the typical equivalent beam finite element models.