The purpose of this study was the analytical safety evaluation on the super-structure of precast modular bridge using standardized modular members and robotic construction during the transportation routing and lifting conditions. In order to evaluate the safety performance of the bridge system, 3-D full scale Finite Element (FE) of 40 m standardized modular block was developed in ABAQUS, followed by the analytical study to classify the structural system according to steel girder structures: 1) modular bridge block lifting method including the steel girder system; 2) modular bridge block lifting method without the steel girder system. The results from the analytical study revealed that the maximum stress of each modular member was within the maximum allowable stresses during lifting condition. However, the stress concentration at the connected area was more critical in comparison to the behavior of 40 m combined modular blocks during lifting time

This study presented the analytical safety evaluation of precast modular bridge super-structure, using standardized modular members and robotic construction during the transportation routing and lifting conditions. In order to evaluate the safety performance of the bridge system, linear and nonlinear 3D full scale Finite Element (FE) for 12 m and 16 m standardized modular blocks was developed in ABAQUS and then analytical study was classified into two different structural systems according to steel girder structures: 1) modular bridge block lifting method including the steel girder system; 2) modular bridge block lifting method without the steel girder system. As a result, in analytical study, the results revealed that the maximum stress of each modular member was in maximum allowable stresses, during lifting condition. However, the stress concentration at the connected area was more critical in comparison to the behavior of entire modular blocks both 12 m and 16m, during lifting time.

Successful development of weapon systems requires a stringent verification and validation (V&V) process due to the nature of the weapons in which continual increase of operational capability makes the system requirements more complicated to meet. Thus, test and evaluation (T&E) of weapon systems is becoming more difficult. In such a situation, live fire tests appear to be effective and useful methods in not only carrying out V&V of the weapon systems under development, but also increasing the maturity of the end users operability of the system. However, during the process for live fire tests, a variety of accidents or mishaps can happen due to explosion, pyro, separation, and so on. As such, appropriate means to mitigate mishap possibilities should be provided and applied during the live fire tests. To study a way of how to accomplish it is the objective of this paper. To do so, top-level sources of hazard are first identified. A framework for T&E is also described. Then, to enhance the test range safety, it is discussed how test scenarios can be generated. The proposed method is based on the use of the anticipatory failure determination (AFD) and multiple event tree analysis (ETA) in analyzing range safety. It is intended to identify unexpected hazard components even in the environment with constraints. It is therefore expected to reduce accident possibilities as an alternative to the traditional root-cause analysis.

인양장비는 원자력발전소에서 발생하는 사용후핵연료를 운반하는 운반용기를 인양하기 위해 사용된다. 본 연구는 원자력 안전위원회고시 제2013-27호와 미국 10CFR Part 71 §71.45에서 규정하는 기술수준에 따라 이론적인 방법과 유한요소방법 으로 인양장비의 구조적안전성을 평가하였다. 이론적으로 평가한 결과 모든 구성 요소에서의 응력이 응력제한치 내에 있어 운영상 발생하는 구조적 안전성을 확보하고 있는 것으로 판단하였다. 또한 유한요소해석을 통한 평가결과, 항복과 극한조건 모두에서 설계기준을 만족하는 것으로 평가되었다. 모든 구성요소에서 충분한 안전여유도(항복조건에서 3 이상의 안전율, 극한조건에서 5 이상의 안전율)를 갖는 것으로 나타나 구조적으로 안전하다고 판단하였다.

Recently, there are a lot of fires breaking out at special structures. To suppress this fire break down at early stage is very important because it leads to bigger damage in case of special structures. For early suppression, outer wall of building has to be destroyed and need waterproofing for Ignition temperature. So far there is no equipment developed local and all of them are imported from a broad. In this study, In this study, The CAE analysis was the Leading-in of the boom conditions for the development of demolition fire according to the environment of Korea. As a result of this, could be confirmed that decreases stress reduction. maximum 51% to 12% depending on the part. It was possible structural integrity and design. about Telescopic Boom and Outrigger on the basis of this result.

This study carried out passenger safety assessment by real car crash simulation of composite post structures for road facilities. The effects of different material properties of composites for various parameters are studied using the LS-DYNA finite element program for this study. In this study, the existing finite element analysis of steel post structures using the LS-DYNA program is further extended to study dynamic behaviors of the structures made of various composite materials. The numerical results for various parameters are verified by comparing different models with displacements and stress distribution occurred in the post and car.

Pultruded glass fiber reinforced polymeric plastic (PFRP) and FRP member manufactured by sheet molding compound (SMC) have superior mechanical and physical properties compared with those of conventional structural materials. Since FRP has an excellent corrosion-resistance and high specific strength and stiffness, the FRP material may be highly appreciated for the development of floating-type photovoltaic (PV) power generation system. In this paper, advanced floating PV generation system made of PFRP and SMC is designed. In the design, it includes tracking solar altitude by tilting photovoltaic arrays and tracking solar azimuth by spinning structures. Moreover, the results of the finite element analysis (FEA) are presented to confirm stability of entire structure under the external loads. Additionally, installation procedure and mooring systems in the Hap-Cheon Dam are discussed and the measurement of strain under the actual circumstances is conducted for assuring stability of actually installed structures. Finally, by comparison with allowable stress, appropriate safety of structure is confirmed to operate the system.

This study presents a structural safety analysis method for a plant annunciator panel under the seismic effect. Seismic qualification analysis for the nuclear plant annunciator panel is carried out to confirm the structural integrity and the results are represented by required response spectra. For the numerical analysis, finite element method is adopted. Mode combinations are also used to obtain the reliability of the spectrum analysis. The analysis results shows that the nuclear plant annunciator panel is designed as a dynamically rigid assembly, without any resonance frequency blow 33Hz. The calculated stress of the nuclear plant annunciator panel is much less than yield stress of used steel.

This study aims to evaluate structural safety through FEM on the hollow shaft and the shaft filled with aluminum foam as the impact beam made of high tensile strength steel, Force reactions of impact beams are investigated when the forced displacement of 50mm is applied equally on two beams. When impact velocity of 80km/h is applied onto impact beams equally with the limit velocity of automobile on national road, how much impact energies can be absorbed by beams are also investigated. As study result, impact beams without aluminum foam and with aluminum foam show the maximum reaction forces of 15.53kN and 20.34kN respectively in case of the forced displacement of 50mm. As impact analysis result, impact beams without aluminum foam and with aluminum foam can absorb impact energies of 560J and 820J respectively. As impact beam with aluminum foam has reaction force and impact energy more than 23% and 30% than without aluminum foam, impact beam with aluminum foam has more safety than without aluminum foam.

Fire disasters have frequently happened in concrete structures, which resulted in severe structural damages and unsafety. In this case, the method which had evaluated the safety of damaged structures was often unaccepted from most of stakeholders and engineers. The objective of this study is to develope the procedure and method to be able to determine the safety. Numerical simulation was applied to produce the maximum temperature and temperature distribution. Nextly, temperature propagation analysis was performed to plot temperature gradients at each depth and location. The material strength curve versus temperature was applied to determine the safety of concrete structures damaged by fire. The maximum temperature should be calibrated considering real fire records ; magnitude, intensity, situation etc. The results shows that the selected procedure and method was applicable and practical.

소득의 향상 및 연안지역 접근성 개선으로 해양관광 활동에 대한 관심증가 및 해양레저에 대한 수요가 증가하고 있으나, 해상에서의 레저선박과 인명의 안전을 위한 시스템 개발은 미비한 실정이다. 레저선박의 경우 구조안전성에 관한 규정 및 적용 기준이 명확히 정립되어있 지 않으며, 안전성 평가를 위한 시스템 개발이 전무하여 레저보트의 운항안전성 확보를 위한 레저보트 구조안전모니터링시스템의 개발이 필요 하다, 본 연구에서는 도파로 어레이 격자(AWG)와 광섬유 브래그 격자센서(FBG)를 이용하여 레저보트의 실시간 구조안전모니터링 가능한 시스 템을 개발하여 해상에서의 인명과 레저보트의 안전성을 확보하고자 한다.

본 연구의 대상은 1-2W 기본형 온실의 기둥을 절단하여 동일한 규격의 파이프로 용접하여 온실의 측 고를 높인 온실이다. 이와 같이 개조형 온실에 풍하중이나 적설하중이 작용할 경우, 어떠한 형태로든 용 접부위에는 구조적으로 불안전 할 것으로 판단된다. 이를 검토학기 위하여 4단계에 걸쳐 용접된 기둥에 대한 굽힘 강도를 측정하여 용접하지 않은 원상태의 파이프와 비교 검토한 결과는 다음과 같다. 온실구조용 강관에 대한 용접결합부의 굽힘 시험의 경우, 하중재하 방법에 관계없이 양단 지점부위와 하중 재하부위가 하중을 견디지 못하고 함몰되는 현상을 보임으로서 합리적인 결과를 도출할 수가 없었 다. 따라서 지점 및 하중 재하부위에 내부 파이프 (봉강)을 삽입함으로서 부분적인 문제점을 보완할 수 있었지만, 보다 합리적인 굽힘 시험 방법이 고안되어야 할 것으로 판단되었다. 용접결합부의 강도는 원형 상태에 비해 별 차이를 보이지 않았고, 시료의 제작 조건에 따라 경미한 차이를 보였으나, 용접 과정에서 부실의 정도가 결정적인 강도 손실을 유발할 수 있음이 예상되었다. 용접결합과정의 문제점이나 접합 작 업 후, 기둥 부재의 기울어짐 등에 대한 문제점이 없다는 전제 하에 용접한 파이프의 강도는 일반적으로 원형상태의 강도에 비해 약 84~90% 정도로 가정함이 합리적일 것으로 판단되었다. 그리고 접합부의 녹 발생이나 기타 용접결합에 따른 중장기적 강도 저하 등을 고려할 때, 부득이한 경우가 아니라면 현재 농 가에서 시도되고 있는 온실의 주요 부재에 대한 구조변경 등은 구조안전성 측면에서 지극히 삼가 되어야 할 것으로 판단되었다.

The current study examined Ag migration from the Ag paste bump in the SABiT technology-applied PCB. A series of experiments were performed to measure the existence/non-existence of Ag in the insulating prepreg region. The average grain size of Ag paste was 30 nm according to X-ray diffraction (XRD) measurement. Conventional XRD showed limitations in finding a small amount of Ag in the prepreg region. The surface morphology and cross section view in the Cu line-Ag paste bump-Cu line structure were observed using a field emission scanning electron microscope (FE-SEM). The amount of Ag as a function of distance from the edge of Ag paste bump was obtained by FE-SEM with energy dispersive spectroscopy (EDS). We used an electron probe micro analyzer (EPMA) to improve the detecting resolution of Ag content and achieved the Ag distribution function as a function of the distance from the edge of the Ag paste bump. The same method with EPMA was applied for Cu filled via instead of Ag paste bump. We compared the distribution function of Ag and Cu, obtained from EPMA, and concluded that there was no considerable Ag migration effect for the SABiT technology-applied printed circuit board (PCB).

파프리카를 재배하는 농가에서는 생산성 증대를 위하여 비닐하우스 측고를 관행 3.0m에서 4.5m까지 높이고 있으나 이에 대한 구조안전성 검토 없이 시공이 이루어지고 있는 실정이다. 이 연구에서는 측고가 4.5m로 상승된 1-2W형 비닐하우스를 대상으로 풍속 40m·s-1, 적설심 40cm의 설계하중에 대하여 구조안전성 분석을 수행하고 적절한 구조보강방법을 제시하였다. 3차원 프레임해석을 이용하여 구조해석을 수행한 결과, 측면 방풍벽의 보강이 반드시 필요한 상태였으며 파프리카 작물하중으로 인하여 매우 취약해지는 중방의 보강이 요구되었다. 측면 보강 방법으로써는 외측 기둥과 방풍벽을 보강이음을 이용하며 서로 연결해주고, 외측 기둥 간격에 따라 방풍벽 부재를 보강하는 방법이 가장 효과가 큰 것으로 분석되었다. 중방의 경우 비닐하우스 폭의 1/17~1/20의 높이로 2중 중방구조를 만들고 그 사이를 사재로 연결하여 트러스 형태로 보강하는 방법이 가장 큰 효과를 보였다.