• Title/Summary/Keyword: 체결력

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Structure analysis of metal gaskets in tightened flanges (플랜지 체결 시 금속 개스킷의 구조해석)

  • IN, S.R.;Yoon, B.J.
    • Journal of the Korean Vacuum Society
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    • v.15 no.5
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    • pp.475-484
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    • 2006
  • The deformation, the stress distribution, and the contact pressure of gaskets used in sealing flanges of CF (Con-Flat) or IPD (Improved) type were calculated to investigate the possibility of analyzing and estimatimg the sealing performance under a given tightening condition for a specific flange system.

Development of the Friction Type Coupler for Big Size Steel bars (나사산 밀착방식의 철근 커플러의 개발에 관한 연구)

  • Lee, Seong-Yeun;Kim, Kwang-Man;Yoon, Sang-Moon;Lee, In-Hyuck
    • Proceedings of the Korea Concrete Institute Conference
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    • 2009.05a
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    • pp.151-152
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    • 2009
  • This study suggested a friction type coupler designed to contact the male and internal screw groove together by tightening the outer nut formed along the inclined outside of the coupler. In order to tighten the outer nut conveniently, special openable wrenches were developed. To confirm the quality of this coupler, visual inspection method (counting the number of screw threads) was applied.

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Experimental Study on the Shock Response of a Cylindrical Structure with the Bolted Joint (조인트를 가진 원통형 구조물의 충격 응답에 관한 실험적 연구)

  • Jeon, Ho-Chan;Song, Ohseop
    • Journal of the Korea Institute of Military Science and Technology
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    • v.22 no.5
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    • pp.581-589
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    • 2019
  • Guided missiles assembled with the bolted joint are subjected to various shock loading conditions while flying in the air and operating on the ground or platform. Especially, It is important to analyze the effect of the shock load on the structure because it affects the structure for a short duration time while its acceleration magnitude is quite large. In this study, mechanical shock tests on the structure with the bolted joint have been carried out to measure the acceleration changes of the structure against external shock loads by electrical exciter. Variation of dynamic characteristics of a structure with fastening methods and fastening forces has been investigated through Shock Response Spectrum analysis.

Evaluation of Long-term Performance of Metal Seal Through Accelerated Test (가속화 시험을 통한 금속 밀봉재 장기성능 평가)

  • Choi, Woo-seok;Lim, Jongmin;Yang, Yun-young;Cho, Sang Soon
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.18 no.2_spc
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    • pp.237-245
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    • 2020
  • Metal seals are the main components that establish the containment boundary in bolted casks, which store spent nuclear fuel. These seals are degraded by heat and radiation. In addition, creep occurs when the seals are exposed to intense heat for an extended period. This creep results in the stress relaxation of the seals, which consequently impairs the seal integrity. The stress relaxation can reduce the sealing performance of the metal seal, which can further cause leakage in the storage cask. Moreover, the reduction of bolt tension leads to sealing performance degradation. In this study, the results of high-temperature-accelerated tests were obtained to evaluate the containment integrity of metal seals and the decrease in bolt tension. During the tests, the leakage rate, bolt strain, and ambient temperature of the metal seals were measured and analyzed. The metal seals were found to maintain containment integrity for 50 years of storage. The validity of the acceleration test was also investigated.

A Study on the Contact Resistance according to the Tightening and Overlapping area of Bus Bar (부스 바의 체결 및 중첩 구간에 따른 접촉 저항에 관한 연구)

  • Kim, Hyun-Woo;Son, Yung-Deug
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.7
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    • pp.56-62
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    • 2018
  • The bus bar is an electrical connection widely used for the power supply of skyscrapers and power distribution and industrial equipment electrical panels in industrial plants. There are various materials to be considered in the design of the bus bar, such as material based on the use environment, the sectional area according to the power capacity, the length of the surface circumference, and the tightening method. Even with a bus bar manufactured to a size of sufficient power capacity in the design, if the actual tightening is incorrect, it may lead to fire due to deterioration. For these reasons, a variety of research on the temperature rise of the electrical contact point has continued. However, the temperature rise of the contacts is a consequence of the result, not a direct cause. In this paper, the influence of contact resistance on the fastening force and the overlapping section of the bus bar are investigated by measuring the change in resistance from building the specimen. A total of eight bus bar specimens were manufactured and measured. Resistance was measured by varying the clamping force and the interval between overlapping sections when the specimens were crossed. We propose a safe power connection model by analyzing the contribution of these factors to the actual contact resistance change.

Development of High Precision Fastening torque performance Nut-runner System (고정밀 체결토크 성능 너트런너 시스템 개발)

  • Kim, Youn-Hyun;Kim, Sol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.4
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    • pp.35-42
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    • 2019
  • Nut fasteners that require ultra-precise control are required in the overall manufacturing industry including electronic products that are currently developing with the automobile industry. Important performance factors when tightening nuts include loosening due to insufficient fastening force, breakage due to excessive fastening, Tightening torque and angle are required to maintain and improve the assembling quality and ensure the life of the product. Nut fasteners, which are now marketed under the name Nut Runner, require high torque and precision torque control, precision angle control, and high speed operation for increased production, and are required for sophisticated torque control dedicated to high output BLDC motors and nut fasteners. It is demanded to develop a high-precision torque control driver and a high-speed, low-speed, high-response precision speed control system, but it does not satisfy the high precision, high torque and high speed operation characteristics required by customers. Therefore, in this paper, we propose a control technique of BLDC motor variable speed control and nut runner based on vector control and torque control based on coordinate transformation of d axis and q axis that can realize low vibration and low noise even at accurate tightening torque and high speed rotation. The performance results were analyzed to confirm that the proposed control satisfies the nut runner performance. In addition, it is confirmed that the pattern is programmed by One-Stage operation clamping method and it is tightened to the target torque exactly after 10,000 [rpm] high speed operation. The problem of tightening torque detection by torque ripple is also solved by using disturbance observer Respectively.

원지점 차넣기 모타 적용 잠입노즐 기초 기술 개발

  • 노태호;황종선;조인현
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2000.04a
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    • pp.32-32
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    • 2000
  • 잠입노즐은 로케트 추진기관의 길이 및 중량을 감소시켜 체계설계의 관점에서 볼 때 많은 이점을 제공한다. 본 연구에서는 3단형 과학로케트 원지점 차넣기 모타(apogee kick motor)에 적용하기위한 잠입노즐의 기초기술 개발에 주안점을 두었다. 고고도에서 저속으로 회전하며 비행하는 원지점 차넣기 모타를 제작하기위해서 체계 요구성능에 의해 예상된 실물형의 50% 크기에 해당하는 축소형 잠입노즐을 제작하였다. 잠입노즐은 잠입부의 내외부가 고온의 추진제 연소가스에 노출된 상태에서 노즐 내부 압력 외에 연소실압에 의한 외부압력이 작용하므로 이를 고려한 열 및 구조설계가 중요하다. 본 연구에서는 노즐 수렴부와 목부에 일체형 그라파이트 소재를 적용하고 확장부 내열재 및 잠입부 배면내열재에 탄소/페놀 복합재를 노즐 내열재로 사용하였다. 그리고 이들의 구조적 지지를 위해 스틸구조물을 적용하였다. 적용된 스틸구조물에는 K형 열전쌍을 이용해 내열재와 구조물 온도를 측정할 수 있는 관통구멍 및 나사부를 구조물 외변에 가공하였다. 열전쌍은 노즐 목직경의 2, 4배 되는 확장부 내열재 단면위치의 2mm와 4mm 깊이와 구조물 내면 및 외면의 4개소에 열전쌍을 부착하여 지상연소시험시 노즐 내열재와 구조물의 온도분포를 관찰한다. 그리고 노즐 조립시 확장부 내열재와 구조물에 각 각 반원형 홈을 내어 여분의 접착제가 원형 홈에 밀려들어가 경화되어 노즐 기밀유지와 체결력을 향상시킬 수 있는 원형공간 접착제 충전 공법을 적용하여 실제모타에 대한 적용가능성을 지상연소시험을 통해 확인한다.

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KSR-III 복합재 가압탱크의 설계 및 제작

  • Kong, Cheol-Won;Yoon, Chong-Hoon;Jang, Young-Soon;Yi, Yeong-Moo
    • Aerospace Engineering and Technology
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    • v.2 no.2
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    • pp.124-132
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    • 2003
  • This paper described the structural design and the fabrication procedure of KSR-III composite pressure tank. The type of the composite pressure tank was COPV(Composite Overwrapped Pressure Vessel). A non-load sharing liner was made of aluminum 6061-0 and the liner provided a helium gas seal. The composite pressure tank was winded using T700 carbon/epoxy on the liner. Because the aluminum liner was thin, multiple cure cycles were applied to the filament winding technique. The multiple cure cycles prevented the liner-cylinder from losing a circular shape. A fitting force at the metallic boss was spread to the carbon fiber by a boss ring. The boss ring also prevented a local deformation at the boss part.

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The Quasi 3-D Flow Simulation in injection Molding Using Virtual Pressure Reflection (가상 반사압력을 이용한 사출성형의 준3차원 유동해석)

  • 이호상;신효철
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.7
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    • pp.1294-1306
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    • 1992
  • In order to determine the design parameters and processing conditions in injection molding, it is very important to establish the theoretical model with scientific base. In this study, a two dimensional model has been developed for the purpose and flow simulations of filling process are carried out. The moving boundary transient flow problem along the flat plane is solved efficiently by the Iterative Boundary Pressure Reflection Method which rearranges the impinged melt front along the physical boundary in scientific manner. The two dimensional modeling of filling process is applied to two examples : a three dimensional cover with two screw holes and a two-gated flat cavity with unbalanced runners. The numerical results show good agreement with experimental short shots, especially for the weldline locations and the pressure traces at various locations. They also provide the temperature, clamp force, and velocity field in the mold at different times during filling of cavity.

A Study on Swaging Characteristics of Band for Low Pressure Hose (저압 호스용 밴드의 체결특성에 관한 연구)

  • Kim Tyoung-Gyu;Kim Pil-Jong;Cho Seok-Beom;Kwon Boo-Kil
    • Journal of the Korean Institute of Gas
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    • v.9 no.3 s.28
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    • pp.32-37
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    • 2005
  • Hose bands, which are used in LPG (Liquefied Petroleum Gas) or LNG (Liquefied Natural Gas) facilities for home use to join low pressure hoses with fuse-cocks (or regulators), should give a tight connection to prevent a gas leakage from hose connection parts. In this paper, hydraulic pressure tests and pull force tests were carried out to evaluate the performance and swaging length of hose bands. Experimental results showed that the swaging force of ear type bands were higher than those of spring bands and also showed that the optimal swaging length was about 1${\~}$2 mm from the hose end.

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