• 한국정밀공학회지
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• 제22권3호
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• pp.93-100
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• 2005

The top and bottom nozzles of PWR fuel assembly are connected by guide thimbles and an instrumentation tube that are connected with spacer grids. The fuel rods are inserted into the each cell of spacer grids. The loads acting on the fuel assembly are transmitted to the guide thimbles through the flow plate of top nozzle The axial loads applied to the fuel assembly are not equally distributed among the guide thimble due to the geometry of the top nozzle flow plate and spacer grid. In this study, the load concentration factors for the $17\times17$ fuel assembly were calculated. The analytical model fur the calculation of the load concentration factor of top nozzle flow plate was developed using ANSYS 5.6. The finite element analyses were performed using the model composed of top nozzle, guide thimble, and spacer grid. And, the analysis results were compared with the test results.

• Structural Engineering and Mechanics
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• 제4권4호
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• pp.397-413
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• 1996

In this paper the elastic post-buckling behaviour of plates under non-uniform compressive edge stress is investigated. The compatibility differential equations is first solved analytically and then an approximate solution of the equilibrium equation is obtained using the Galerkin method. Explicit expressions are derived for the load-deflection, ultimate strength and membrane stress distributions. Analytical effective width formulations, based on the characteristics of the stress field of the buckled plate, are proposed for this general loading condition. The predicted load-deflection expression is compared with independent test results. Results are also presented detailing the load-deflection behaviour and stress distribution for various aspect ratios.

• 대한기계학회논문집A
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• 제31권3호
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• pp.304-312
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• 2007

The objective of this study is to develop a local failure criterion for a wall thinning defect of piping components. For this purpose, a series of tensile tests was performed using several types of simulated specimens with different stress states, including smooth round bar, notched round bar (five different notch radii), and grooved plate (three different groove radii). In addition, finite element (FE) simulations were performed on the simulated specimen tests and the results were compared with the test results. From the comparisons, the equivalent stress and strain corresponding to maximum load and final failure of notched specimens were proposed as failure criteria under tensile load. The criteria were verified by employing them to the estimation of failure of grooved plate specimens that simulate the wall thinning defect. It showed that the proposed criteria accurately estimate the maximum load and final failure of grooved plate specimen tests.

• 복합신소재구조학회 논문집
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• 제4권1호
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• pp.40-46
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• 2013

This paper presents the design, fabrication and performance of a reinforced concrete beam strengthened by GFRP box plate and its possibility for structural rehabilitations. The load capacity, ductility and failure mode of reinforced concrete structures strengthened by FRP box plate were investigated and compared with traditional FRP plate strengthening method. This is intended to assess the feasibility of using FRP box plate for repair and strengthening of damaged RC beams. A series of four-point bending tests were conducted on RC beams with or without strengthening FRP systems the influence of concrete cover thickness on the performance of overall stiffness of the structure. The parameters obtained by the experimental studies were the stiffness, strength, crack width and pattern, failure mode, respectively. The test yielded complete load-deflection curves from which the increase in load capacity and the failure mode was evaluated.

• 한국산학기술학회논문지
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• 제10권9호
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• pp.2402-2408
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• 2009

고장력볼트를 이용한 강부재의 체결에서 모재 및 덮개판의 과대공으로 인한 단면결손이 체결부에서 내하력의 저하가 우려되어 정적 인장시험을 실시하였다. 인장시험을 통하여 구해진 체결부의 파단시 최대하중을 단면결손율 및 설계강도와 비교하여 체결부의 내하력 변화를 파악하였다. 이에 따르면 단면결손율이 클수록 강도저하율이 컸으며 특히, 모재의 단면결손이 덮개판의 단면결손보다 강도저하에 대한 영향이 훨씬 큰 것으로 나타났다. 모재 및 덮개판을 과대공으로 제작한 고장력볼트 체결부는 표준공의 경우보다 내하성능이 다소 저하되었지만 파단시의 최대인장강도는 설계파단강도보다 15%이상 크게 나타났다. 본 연구에서는 과대공으로 제작된 고장력볼트 체결부에서 내하력저하에 미치는 영향이 미미하므로 강부재의 체결시공에 있어 과대공의 허용은 경제성과 효율성의 고취에 기여할 수 있을 것으로 판단되었다.

• KCI Concrete Journal
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• 제12권1호
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• pp.69-77
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• 2000

The reinforced concrete(RC) flexural members strengthened with steel plate/CFS at soffit have initial stresses and strains in reinforcements and concrete caused by the service loads at the time of retrofitting works. These initial residual stresses and strains of strengthened beams may affect the flexural performance of the rehabilitated beams. The objective of this study is to evaluate and verify the effectiveness of rehabilitation by external bonded steel plates and CFS to the tension face of the beams under three conditions of pre-loading. Thirteen beam specimens are tested and analyzed. Main test parameters are pre-loading conditions, strengthening materials and reinforcement ratio of specimens. The effect of test parameters on the strengthened beams is analyzed from the maximum load capacity, load-deflection relationship, state of stress of the materials. crack propagation phase, and failure modes. Both test results and design formulas of ACI Code provisions are compared and evaluated.

• 한국정밀공학회지
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• 제14권6호
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• pp.135-141
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• 1997

Low velocity impact test and compressive residual strength test after impact were performed by using Hercules AS4/3501-6[45/0/-45/90]$_{2s}$ laminated plate to investigate the low velocity impact damage behavior and the post-impact strength degradation on orthotropic composite laminate plate. Due to the lateral impact losd, the load path showed "" shape according to the laminate central deflection. Damage in a laminate occurs by inclined matrix crack at the damage initiation load stage and vertical matrix crack, occurs on the outer surface. Evaluating the compressive residual strength after the low velocty impact test, it could be found that there is a transient range where the compressive residual strength drop suddenly in the initial damage which is in the matrix crack range and the initial delamination area. is in the matrix crack range and the initial delamination area.

• 한국방재학회 논문집
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• 제5권1호
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• pp.33-43
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• 2005

한국 도로교 설계기준과 AASHTO Standard 설계규준에 규정된 판형교의 윤하중분배계수는 사각의 영향을 고려하지 못하고 있으며, 이에 대한 연구는 매우 미흡한 실정이다. 본 연구에서는 검증된 유한요소해석모델을 이용, 다양한 변수를 고려한 구조해석을 통하여 강판형 사교에 대한 하중분배계수식의 제안을 목적으로 한다. 판형교의 유한요소모델은 현장실험과의 비교분석을 통해 선택되었으며, 이를 이용하여 강판형사교의 유한요소해석을 수행하였다. 연구결과 지간은 다른 변수들에 비해 윤하중분배계수에 미치는 영향이 작았고, 가로보와 브레이싱을 사교격자 구조로 설치할 경우 내측거더에서는 하중분배가 향상되며, 브레이싱 타입이 보다 유리한 것으로 밝혀졌다. 또한 해석결과를 바탕으로 회귀분석을 통해서 윤하중분배계수식을 제시하였고, 기존식과 비교검토하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제9권1호
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• pp.293-303
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• 2005

한국 도로교 설계기준과 AASHTO Standard 설계규준에 규정된 판형교의 윤하중분배계수는 사각의 영향을 고려하지 못하고 있으며, 이에 대한 연구는 매우 미흡한 실정이다. 본 연구에서는 검증된 유한요소해석 모델을 이용, 다양한 변수를 고려한 구조해석을 통하여 강판형 사교에 대한 하중분배계수식의 제안을 목적으로 한다. 판형교의 유한요소모델은 현장실험과의 비교분석을 통해 선택되었으며, 이를 이용하여 강판형사교의 유한요소해석을 수행하였다. 연구결과 지간은 다른 변수들에 비해 윤하중분배계수에 미치는 영향이 작았고, 가로보와 브레이싱을 사교격자 구조로 설치할 경우 내측거더에서는 하중분배가 향상되며, 브레이싱 타입이 보다 유리한 것으로 밝혀졌다. 또한 해석결과를 바탕으로 회귀분석을 통해서 윤하중분배계수식을 제시하였고, 기존식과 비교검토하였다.

• 한국농공학회논문집
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• 제59권5호
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• pp.73-81
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• 2017

The improved movable weir supplements the advantages and disadvantages of the rubber weir and the conduction gate. It consists of a stainless steel gate, air bags, and a steel clamping plate. The stainless steel gate is the main body of the weir, and the inflatable rubber sheet serves to support the steel gate. The steel clamping plate is typically in direct continuous contact with water, but this leads to corrosion issues that can reduce the life of the entire movable weir. In this study, a panel-type glass-fiber-reinforced polymer (GFRP) clamping plate was designed and fabricated. The test results showed that the flexural load of the panel-type GFRP composite clamping plate was over twice that of the wings type GFRP clamping plate. The lowest moisture absorption value was obtained upon exposure to tap water, and exposure to other solutions showed similar values. Additionally, flexural load testing after exposure to an accelerated environment found the lowest residual loads of 80.51 % and 78.50 % at 50 and 100 days, respectively, for exposure to a $CaCl_2$ solution, while exposure to other environments showed residual failure loads of over 80 % at both 50 and 100 days.