• Title/Summary/Keyword: 폭발손상평가

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Development of Laminated Blade Based Shock Absorber Using Viscoelastic Adhesive Tape (점탄성 테이프를 적용한 적층형 블레이드 기반 충격저감장치)

  • Jae-Seop Choi;Yeon-Hyeok Park;Hyun-Ung Oh
    • Journal of Aerospace System Engineering
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    • v.17 no.2
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    • pp.86-93
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    • 2023
  • Pyrotechnic separation devices have been widely used as holding and release mechanism for deployable appendage. However, pyro-shock can cause temporal or permanent damage on shock sensitive components such as electronics, mechanism, and brittle components. This study proposed a low-stiffness blade based passive shock absorber using a multi-layered stiffener laminated with viscoelastic acrylic tapes for reducing transmitted pyro-shock upon explosion of pyrotechnic separation devices. The multi-layered structure with viscoelastic tape has high-damping characteristics to effectively secure structural integrity of low-stiffness blades under the launch environment. The design effectiveness was verified through a shock test by dropping a pendulum. The structural integrity of the shock absorber under a launch environment was evaluated through structural analysis under load conditions with a deployable payload.

Numerical Study on Columns Subjected to Blast Load Considering Compressive Behavior of Steel Fiber Reinforced Concrete (강섬유보강콘크리트의 압축거동 특성을 반영한 기둥의 내폭해석 )

  • Jae-Min Kim;Sang-Hoon Lee;Jae Hyun Kim;Kang Su Kim
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.5
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    • pp.105-112
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    • 2023
  • Steel fiber reinforced concrete (SFRC) exhibits enhanced strength and superior energy dissipation capacity compared to normal concrete, and it can also reduce crack propagation and fragmentation of concrete even when subjected to blast loads. In this study, the parameters defining failure surface and damage function of the K&C concrete nonlinear model were proposed to be applied for the properties of SFRC in LS-DYNA. Single element analysis has been conducted to validate the proposed parameters in the K&C model, which provided very close simulations on the compressive behavior of SFRC. In addition, blast analysis was performed on SFRC columns with different volume fractions of steel fibers, and the blast resistance of SFRC columns was quantitatively analyzed with Korea Occupational Safety & Health Agency (KOSHA) guidelines.

Consequence Analysis of the Fire & Explosion on the Flammable Liquid Handling Facility and LPG Station (제 4류 위험물 취급소 및 LPG 충전소의 화재$\cdot$폭발 피해 영향분석)

  • Lee Su-Kyung;Lee Chang-Wook
    • Journal of the Korean Institute of Gas
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    • v.3 no.2 s.7
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    • pp.77-84
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    • 1999
  • The XX company that is handling the class IV hazardous materials, located in Bu-Chon City and the LPG station in front of the XX company which is about 20 meters apart, was chosen as the standard model for this study In carrying out the consequence analysis, PHAST and Super-Chems were used for the study and utilizing the output of the simulation, we have evaluated the consequences throughout the probit analysis and explosion overpressure analysis. In case of Acetone, the effect distance of the damage on facilities-that is the result of radiation heat flux of $37.5kW/m^2$ by TNO model-is 68.51m by PHAST model and 40.93m by Super-Chem model. The risk assessment of the LPG station which is based on the explosion resulted as the analysis of the fire ball showed the diameter 125.2m, the height 206.2m and the duration 11.28sec and the effect distance for the radiant heat flux $37.5kW/m^2$ was 137.0m.

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Seismic Fragility Assessment of Liquid Storage Tanks by Finite Element Reliability Analysis (유한요소 신뢰성 해석을 통한 액체저장탱크의 지진 취약도 평가)

  • Lee, Sangmok;Lee, Young-Joo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.4
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    • pp.718-725
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    • 2017
  • A liquid storage tank is one of the most important structures in industrial complexes dealing with chemicals, and its structural damage due to an earthquake may cause a disastrous event such as the leakage of hazardous materials, fire, and explosion. It is thus essential to assess the seismic fragility of liquid storage tanks and prepare for seismic events in advance. When a liquid storage tank is oscillated by a seismic load, the hydrodynamic pressure caused by the liquid-structure interaction increases the stress and causes structural damage to the tank. Meanwhile, the seismic fragility of the structure can be estimated by considering the various sources of uncertainty and calculating the failure probabilities in a given limiting state. To accurately evaluate the seismic fragility of liquid storage tanks, a sophisticated finite element analysis is required during their reliability analysis. Therefore, in this study, FERUM-ABAQUS, a recently-developed computational platform integrated with commercial finite element and reliability analysis software packages, is introduced to perform the finite element reliability analysis and calculate the failure probability of a liquid storage tank subjected to a seismic load. FERUM-ABAUS allows for automatic data exchange between these two software packages and for the efficient seismic fragility assessment of a structure. Using this computational platform, the seismic fragility curve of a liquid storage tank is successfully obtained.

Study on the Dynamic Response Characteristics of Impact Force Sensors Based on the Strain Gage Measurement Principle (변형률 게이지 측정원리를 이용한 충격하중 측정 센서의 동적응답 특성에 관한 연구)

  • Ahn, Jung-Lyang;Kim, Seung-Kon;Sung, Nak-Hoon;Song, Young-Soo;Cho, Sang-Ho
    • Explosives and Blasting
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    • v.29 no.1
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    • pp.41-47
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    • 2011
  • In order to estimate blast damage zone and control rock fragmentation in blasting, it is important to obtain information regarding blast hole pressure. In this study, drop impact tests of acrylic, aluminium, steel sensors were performed to investigate the dynamic response characterizations of the sensors through the strain signals. As a result, the strain signals obtained from the steel sensors showed less sensitivity to impact force level and experienced small changes with various length of the sensors. The steel sensors were applied to measure the impact force of an electric detonator.

Probabilistic Safety Assessment of Gas Plant Using Fault Tree-based Bayesian Network (고장수목 기반 베이지안 네트워크를 이용한 가스 플랜트 시스템의 확률론적 안전성 평가)

  • Se-Hyeok Lee;Changuk Mun;Sangki Park;Jeong-Rae Cho;Junho Song
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.36 no.4
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    • pp.273-282
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    • 2023
  • Probabilistic safety assessment (PSA) has been widely used to evaluate the seismic risk of nuclear power plants (NPPs). However, studies on seismic PSA for process plants, such as gas plants, oil refineries, and chemical plants, have been scarce. This is because the major disasters to which these process plants are vulnerable include explosions, fires, and release (or dispersion) of toxic chemicals. However, seismic PSA is essential for the plants located in regions with significant earthquake risks. Seismic PSA entails probabilistic seismic hazard analysis (PSHA), event tree analysis (ETA), fault tree analysis (FTA), and fragility analysis for the structures and essential equipment items. Among those analyses, ETA can depict the accident sequence for core damage, which is the worst disaster and top event concerning NPPs. However, there is no general top event with regard to process plants. Therefore, PSA cannot be directly applied to process plants. Moreover, there is a paucity of studies on developing fragility curves for various equipment. This paper introduces PSA for gas plants based on FTA, which is then transformed into Bayesian network, that is, a probabilistic graph model that can aid risk-informed decision-making. Finally, the proposed method is applied to a gas plant, and several decision-making cases are demonstrated.

Safety Assessment of By-product Gas Piping after Design Change (부생가스 연료배관의 설계변경에 따른 안전성 평가)

  • Yoon, Kee Bong;Nguyen, Van Giang;Nguyen, Tuan Son;Jeong, Seong Yong;Lee, Joo Young;Kim, Ji Yoon
    • Journal of the Korean Institute of Gas
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    • v.17 no.2
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    • pp.50-58
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    • 2013
  • Various process piping usually carries out high flammable and explosible gas under high pressure and high temperature. Due to frequent change of design and structure it becomes more complicated and compactly located. The safety management level is relatively low since it is considered as simply designed component. In this study a safety assessment procedure is proposed for complicated piping system around a mixing drum in which natural gas and by-product gases were mixed. According to ASME code, pipe stress analysis was conducted for determining design margin at some key locations of the piping. These high stress locations can be used as major inspection points for managing the pipe integrity. Sensitivity analysis with outside temperature of the pipe and support constraint condition. Possible effect of hydroen gas to the pipe steel during the previous use of the by-product gas was also discussed.

A Seasonal Risk Analysis and Damage Effects Assessment by Gas Leakage of Chemical Plant using 3D Scan and FLACS (3D 스캔과 FLACS를 활용한 화학플랜트 가스 누출의 계절별 위험성 및 피해영향 평가)

  • Kim, Jiyoung;Kim, Jiyu;Kim, Euisoo
    • Journal of the Korean Institute of Gas
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    • v.25 no.4
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    • pp.1-9
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    • 2021
  • The process and facilities of modern chemical plants are becoming increasingly complex, there is possibility of potential risk. Internal chemicals generate stress concentration when operated due to turbulence, laminar flow, pressure, temperature, friction, etc. It causes cumulative fatigue damage, which can damage or rupture chemical facilities and devices. The statistics of chemical accidents found that the highest rate of occurrence was in summer, and in the last five years statistics on chemical accidents, leakage incidents make up a decent percentage of accidents. Chemical leaks can cause serious human damage and economic damage, including explosions and environmental pollution. In this study, based on the leak accident of chemical plant, the risk analysis, and damage effects assessment were estimated using a 3D scanner and FLACS. As a result, if chemicals leak in summer, the risk is higher than in other seasons, the seasonal safety management measures, and countermeasure were estimated.

A Study on the Evaluations of Damage Impact due to VCE in Liquid Hydrogen Charging Station (액화수소 충전스테이션에서 VCE로 인한 피해영향평가에 관한 연구)

  • Lee, Suji;Chon, Young Woo;Lee, Ik Mo;Hwang, Yong Woo
    • Journal of the Korean Institute of Gas
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    • v.21 no.5
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    • pp.56-63
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    • 2017
  • Hydrogen charging station was invested and supported around the world. In this study, the extent of damage caused by VCE in the charging station handling liquefied hydrogen was calculated, and the human and material damage was estimated through the Probit model. In addition The optimal height of vent stack for low temperature hydrogen was set. The damage range is 8.24m in small scale, 14.10m in medium scale, and 22.38m in large scale based on interest overpressure 6.9kPa. In case of death due to pulmonary hemorrhage, 50m of the small and medium scale and 100m of the large scale were injured. Structural damage was 200m in small scale, 300m in medium scale and 500m in large scale. The optimum height of the vent stack is 4.7 m in small scale, 8.8 m in medium scale and 16.9 m in large scale.

Evaluating Impact Resistance of Externally Strengthened Steel Fiber Reinforced Concrete Slab with Fiber Reinforced Polymers (섬유 보강재로 외부 보강된 강섬유 보강 콘크리트 슬래브의 충격저항성능 평가)

  • Yoo, Doo-Yeol;Min, Kyung-Hwan;Lee, Jin-Young;Yoon, Young-Soo
    • Journal of the Korea Concrete Institute
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    • v.24 no.3
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    • pp.293-303
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    • 2012
  • Recently, as construction technology improved, concrete structures not only became larger, taller and longer but were able to perform various functions. However, if extreme loads such as impact, blast, and fire are applied to those structures, it would cause severe property damages and human casualties. Especially, the structural responses from extreme loading are totally different than that from quasi-static loading, because large pressure is applied to structures from mass acceleration effect of impact and blast loads. Therefore, the strain rate effect and damage levels should be considered when concrete structure is designed. In this study, the low velocity impact loading test of steel fiber reinforced concrete (SFRC) slabs including 0%~1.5% (by volume) of steel fibers, and strengthened with two types of FRP sheets was performed to develop an impact resistant structural member. From the test results, the maximum impact load, dissipated energy and the number of drop to failure increased, whereas the maximum displacement and support rotation were reduced by strengthening SFRC slab with FRP sheets in tensile zone. The test results showed that the impact resistance of concrete slab can be substantially improved by externally strengthening using FRP sheets. This result can be used in designing of primary facilities exposed to such extreme loads. The dynamic responses of SFRC slab strengthened with FRP sheets under low velocity impact load were also analyzed using LS-DYNA, a finite element analysis program with an explicit time integration scheme. The comparison of test and analytical results showed that they were within 5% of error with respect to maximum displacements.