• 한국정밀공학회지
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• 제16권4호통권97호
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• pp.122-128
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• 1999

Bolted joint assembly for nuclear power plants consists of various components : cover plate, retainer plate, manway flange, gasket and stud bolts/nuts. To guarantee the soundness of the joint, it is important to prevent leakage through the gasket and reduce the stress concentration factor at the thread root. In this paper, Submodeling technique for the finite element method is proposed to accurately compute three dimensional contact stresses which govern the sealing performance and the maximum contact stresses at the threads root. For verification of global solutions used as boundary conditions of submodel solution, the stresses on the cover plate and the manway flange are measured by strain gages when internal pressure is applied to the bolted joint assembly. The numerical results are compared with the experimental results.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.228-231
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• 2004

For the bolted joint of the composite structure, quasi-isotropic stacking is generally used to increase the bearing strength. For the bolted joint of uni-directional composite, the fatigue life limit of the bolted joint can be improved by applying clamping force though the static strength is still very low. In this paper, the static and fatigue characteristics of hybrid joint are investigated which can overcome the disadvantage of the bolted joint of uni-directional composite under static loading by applying adhesive joining. The experimental result shows that the static strength and fatigue life can be improved by applying clamping force to the hybrid joint and the hybrid joint is a good solution for the efficiency of the composite structures.

• Structural Engineering and Mechanics
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• 제12권4호
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• pp.397-408
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• 2001

Bolted connections are used commonly in the precast reinforced concrete structures. In such structures, to perform structural analysis, behaviour of connections must be determined. In this study, elastic rotation stiffness of semi-rigid bolted beam connections, applied in industrial precast structures, are determined by finite element methods. The results obtained from numerical solutions are compared with an experimental study carried out for the same connections. Furthermore, stress distributions of the connection zone are determined and a reinforcement scheme is proposed. Thus, a more appropriate reinforcement arrangement for the connection zone is enabled. The connection joint of the prefabricated frame is described as rigid, hinged or elastic, and a static analysis of the frame system is performed for each case. Values of bending moments and displacements obtained from the three solutions are compared and the effects of elastic connection are discussed.

• 항공우주시스템공학회지
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• 제13권6호
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• pp.26-35
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• 2019

본 논문에서는 항공우주분야 등 여러 분야에서 사용되는 복합재 볼트 체결부에 대해 점진적 파손 해석을 수행하였다. 단일 볼트 체결 시편에 대한 해석을 통해 해석 방법에 대해 검증하고 이를 이용해 이 중 볼트 체결 시편의 점진적 파손에 관해 연구하였다. 점진적 파손 해석을 위해 Hashin 파손 판정식과 에너지 기반 점진적 파손모델을 사용하였다. 복합재료의 4가지 파손모드에 대해 손상변수를 정의했다. 이에 따른 물성저하를 계산하였다. 단일 볼트로 체결된 시편에 대해 시험 및 점진적 파손해석을 수행하여 시험 및 해석결과를 비교한 결과 약 5% 이하의 오차로 해석의 신뢰성을 확인하였다. 이중 볼트 체결 시편에 대해 점진적 파손해석을 이용해 볼트 원공으로부터 모서리까지의 거리와 볼트 사이의 간격을 고려하여 이중 볼트 체결부에 대한 매개변수 분석을 수행하였다.

• 한국강구조학회 논문집
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• 제25권5호
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• pp.463-474
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• 2013

일면전단 오스테나이트계 스테인리스강 및 탄소강에 관한 많은 실험 및 해석적 연구가 수행되어졌고, 수정된 내력평가식이 제안되었다. 본 연구에서는 볼트배열(2행 1열, 2행 2열)과 하중방향 연단거리를 주요변수로 하여 이면전단 볼트접합부 실험체가 제작되었고, 단순인장실험이 실시되었다. 고정변수로는 하중직각방향 연단거리, 볼트직경, 피치, 게이지를 설정하였다. 최대내력과 파단형태와 같은 실험결과와 현행기준식에 의한 예측결과와 비교 검토되었다. 볼트배열에 따른 블록전단내력평가식이 제안되었다.

• 한국강구조학회 논문집
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• 제23권5호
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• pp.629-636
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• 2011

본 연구는 압전 센서를 이용한 구조물의 실시간 모니터링과 강구조물 볼트접합부의 동적 컨트롤이 가능한 자가치유 시스템에 관한 것이다. 볼트접합부의 볼트 풀림 손상 탐색을 위해서 압전 물질의 전기역학적 커플링 성질을 이용하는 임피던스 기반의 구조물건전성평가 기법을 이용하였다. 계측된 임피던스 값을 기준치 값과 비교함으로써 볼트 풀림 손상 진단이 가능하다. 볼트 풀림 손상은 손상지수를 이용하여 정량적으로 평가되어지고, 손상이 진단되면 형상기억합금 와셔에 감겨있는 외부히터가 와셔에 열을 가하게 된다. 열이 가해진 형상기억합금 와셔는 축방향으로 팽창하고, 볼트접합부는 볼트풀림으로 인해 잃어버린 토크력을 회복하게 된다. 압전 센서를 이용한 임피던스 기반의 구조물건전성 평가기법과 형상기억합금 기반의 볼트접합부 동적 컨트롤 기능과 이를 이용한 자가치유 볼트접합부 시스템의 적용가능성과 성능을 실험을 통해 평가하였다.

• 품질경영학회지
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• 제43권3호
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• pp.289-298
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• 2015

Purpose: This study examined the problem of crack formation in the fire control system(FCS) of the K11 objective individual combat weapon(OCIW), using design of experiment analysis. Three hypothesis were considered. The first hypothesis is that bolted joint has an effect on impulse caused by firing the weapon and the second hypothesis is that a short time interval of shooting has an effect on impulse and lastly, the third hypothesis is that a positive correlation has between the bolted joint of the FCS and the impulse. Methods: The relationship between the bolted joint and the impulse cause by firing the weapon were examined experimentally. The first and second hypothesis was tested using correlation analysis and the t-test. Results: Using ANOVA, the first null hypothesis was rejected and the alternative hypothesis was accepted. ANONA confirmed the second null hypothesis. Correlation analysis dismissed the last null hypothesis. A positive correlation between the bolted joint and the impulse caused by shooting the weapon was verified. Conclusion: The bolted joint of the K11 FCS and the barrel of the K11 affect the impulse caused by firing the weapon. A positive correlation was established between the bolted joint of the FCS and the impulse on firing the K11 OICW.

• Journal of the Korean Wood Science and Technology
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• 제48권5호
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• pp.676-684
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• 2020

This study was carried out in order to evaluate the bending creep deflection of glulams and bolted glulams beam-to-beam connection with steel-gusset plates and bolts under changing relative humidity. The two types of glulam beams (130 mm in width, 175 mm in thickness, and 3000 mm in length) used in this study were made from domestic larch and composed of seven layers. The gussets were made of 8-mm-thick steel plates. Creep testing was conducted under constant loads in an uncontrolled environment. The test was carried out in a room that was well ventilated through a window. The creep test specimens were loaded for 33,000 hours. A bending creep test for the glulams was conducted through four-point loading. The applied stresses were 20% and 30% of the MOR in the static bending test for the glulam and bolted glulam, respectively. After 33,000 hours, the creep deflection of the glulam at a 20% stress level increased by 39% to 99%, while the creep deflection of the glulam at a 30% stress level increased by 27% to 67%, as compared with instantaneous elastic deflection. The relative creep increased during autumn and winter, and recovered during spring and summer. The relative creep of the bolted glulams was changed abruptly by loading up to 5,000 hours, but stabilized after 5,000 hours, and then gradually increased until 33,000 hours. The relative creep of the bolted glulam increased 2.11 times on average after 33,000 hours.

• 도시과학
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• 제11권2호
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• pp.25-30
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• 2022

Resin Transfer Molding FRP (RTM FRP) is a fiber reinforced polymeric plastic which is manufactured by applying pressure to fibers, injecting resin into a mold, and then impregnating it. RTM FRP is a new construction material suitable for producing non-continuum structural elements such as sole plate because it has excellent strength and can produce many members in a short time. In this study, experiments were conducted to estimate the capacity of the bolted connection of RTM FRP. First, a tensile test was conducted to confirm the mechanical properties such as the tensile strength of the RTM FRP to be used for the bolted connection experiments. In addition, experiments were conducted on the bolted connection with the thickness of the RTM FRP and the edge distance of the bolt as variables. In the first experiment, F4.8 bolts were used, and shear failure of the bolt occurred before the RTM FRPs were failed. The F4.8 bolt is a general structural bolts used for the sole plate of a bridge bearing, and it was confirmed that the RTM FRP has a higher bold bearing strength than the shear strength of a F4.8 bolt. In the second experiment, G12.9 bolts were used, and shear failure of the bolt and bearing failure of the RTM FRP occurred simultaneously. In addition, as the thickness of the RTM FRP and the edge length of the bolt increased, the strength of the joint increased. When analogized with the bearing fracture equation of steel plate, the bolted connection of RTM FRP showed a bearing strength coefficient of 0.420 to 0.549 compared to the tensile strength, and it is considered that further research is needed.

• 산업기술연구
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• 제9권
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• pp.21-28
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• 1989

For the study of the fatigue behavior, high-strength bolted connections on a small scale were manufactured, and carried on fatigue tests. Its experimental values were analysed by stress-fatigue life (S-N) curve. Three types of specimens : the base metal, the cireular hole and the welded sperimens had same net section were made. Through the same tests those experimental values were compared with those of the high-strength bolted conneetions. The results of these studies are as followings. It was found that the fatigue strength in $F_{n=100,000}$ and $F_{n=2,000,000}$ of the high-strength bolted conneetions were much more about 14% and 16% than that of the base metal specimen. It was thought that this trend was due to frictional force increasing fatigue strength. It was known that fatigue strength in $F_{n=100,000}$ and $F_{n=2,000,000}$ of the welded joints were less 29% and 21% than that of base metal specimen. It was thought that that trend was due to weld flaw. It was appeared that the fatigue strength in $F_{n=100,000}$ and $F_{n=2,000,000}$ of the high-strength bolted connections were much more about 38% and 30% than that of welded joint. It was thought that it was due to both frictional force increasing the fatigue strength in bolted connections and weld flaw decreasing the fatigue strength in welded connections. It was found that the fatigue strength in $F_{n=100,000}$ and $F_{n=2,000,000}$ of the B3 specimens were much more 2% and -2% than that of the B4 specimen. It was thought that that trend was due to the frictional force, which concerned with shape of specimen. It was known that the fatigue strength in $F_{n=100,000}$ and $F_{n=2,000,000}$ of the specimen with circular hole was less 61% and 65% than that of base metal. It was known that the allowable stress for bolted joint was higher than that of welded Joints. If that research is continued and more data are accumulated it can be expected that a basic pattern to provided the indicator of the fatigue design of the bolted connections of steel structures and persume the safety and lifeproof of existing structures is given.