• Title/Summary/Keyword: 체결력

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Analysis of Joints Using Metal Seals in Liquid Rocket Engine Turbopump (액체로켓엔진 터보펌프의 금속 실 체결부 해석)

  • Yoon, Suk-Hwan;Jeon, Seong Min;Kim, Jinhan
    • Journal of the Korean Society of Propulsion Engineers
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    • v.17 no.6
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    • pp.105-112
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    • 2013
  • Turbopump is typically an assembly of rotors and casings, and there are a number of joints between them. Every joint should be leak-proof, so there is always a seal to accomplish the goal. Among various seals, metal seals are advantageous in that they are robust at high pressure, and at wide range of temperature. In this study, flange joints using conical seal made of stainless steel, solid flat metal seal made of copper and metal C seal made of Inconel 718 were structurally designed and analyzed, considering both initial tightening and operating conditions.

A Study on the Estimation of Separation Forces of a Power Steering Hose Assembly (동력조향장치 호스 조립품의 이탈력 추정에 관한 연구)

  • Kim Hyungje;Kim Byungtak;Yoon Moonchul
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.4
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    • pp.190-196
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    • 2005
  • The power steering hose assembly is usually manufactured through the swaging process, which is conducted to connect a hose with metal fittings. In this process the hose is inserted into metal components, the sleeve and the nipple, and compressed in the radial direction by the jaws to clamp the hose with metal components. In case that the clamping force is small, the oil in the hose can leak locally under the severe operating conditions. To confirm the clamping force requirements, the measurement of separation force in longitudinal direction of the hose is usually performed. In this study, the swaging process of a hose is simulated with the finite element method, to investigate the effect of friction coefficient on the separation fDrce. The results interpretations are ffcused on the inner rubber component, and also a formula is proposed to estimate the separation farces with respect to friction coefficients.

Evaluation of Clamping Characteristics for Subminiature Screws According to Thread Angle Variation (초소형 나사의 나사산 각도변화에 따른 체결특성 평가)

  • Min, Kyeong Bin;Kim, Jong Bong;Park, Keun;Ra, Seung Woo
    • Journal of the Korean Society for Precision Engineering
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    • v.31 no.9
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    • pp.839-846
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    • 2014
  • Recent trends in the miniaturization and weight reduction of portable electronic parts have driven the use of subminiature screws with a micrometer-scale pitch. As both screw length and pitch decrease in subminiature screws, the resulting clamping force becomes diminishes. In this work, Finite element (FE) analysis is performed to evaluate clamping force of a screw assembly, with a comparison with experimental result. To improve clamping force of subminiature screws, a new screw design is considered by modifying screw thread angle: the thread angle is varied as an asymmetric way unlike the conventional symmetric thread angle. FE analyses are then performed to compare the clamping characteristics of each subminiature screw with different thread angle. The effect of thread angles on the clamping force is then discussed in terms of structural safety for both positive and negative screws.

Shape Memory Alloy Actuator and Spiral Spring Based Separation Actuator for Small Satellite (형상기억합금구동기와 태엽스프링을 이용한 소형위성용 분리장치)

  • Lee, Min-Hyoung;Son, Jae-Hwang;Kim, Young-Woong;Kim, Byung-Kyu
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.19 no.3
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    • pp.10-15
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    • 2011
  • The separation actuator for the small satellite should fix satellite appendages with high clamping force. After operation, it has to be separated from the satellite body without any damage on satellite system and release the appendages such as a solar panel and an antenna successfully. Therefore, we invent a non-explosive separation actuator for the small satellite which generates low shock and is resettable. In order to confirm performance of the proposed separation actuator, we carried out experiments for separation time, maximum preload for activation, and shock level.

Finite Element Analysis for the Forging Process Design of a Blind Rivet (블라인드 리벳의 단조공정설계를 위한 유한요소해석)

  • Byun, Hong-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.10
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    • pp.2577-2582
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    • 2009
  • A rivet which can fasten two parts is one of an important mechanical elements. In this study, the process design of a blind revet is implemented using finite element method in order to manufacture it which can resist high vibration and has strong coherence between two parts. Considering plastic flow, ease of manufacture, high strength, material loss, and so forth, an optimal four-stage process is proposed by finite element analysis and process design rules. In addition, the finite element simulation results such as shape of the forged rivet, strain distribution and forging load are investigated for the usefulness of the forging process of the blind rivet. These results will be contributed to the forging process design and the die design of the blind rivet.

Development of Auto Casting Machine for Rotor Molding of Electric Motor (전동모터의 Rotor 성형을 위한 자동 주조기 개발)

  • Lee, Yang-Chang;Lee, Joon-Seong;Lee, Ho-Jeong;Bae, Byung-Kyu;Choi, Yoon-Jong
    • Proceedings of the KAIS Fall Conference
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    • 2010.11b
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    • pp.824-827
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    • 2010
  • 본 논문은 전동형 모터의 Rotor의 자동 성형을 위한 자동화된 주조기 개발에 대한 결과이다. 개발된 자동화된 Rotor 전용 주조기는 수평형에 비해 금형의 크기가 약 1/2정도 이므로 금형 체결력이 반감되고, 기계 구조는 매우 작아진다. 그리고 Al용탕이 사출되는 과정에서 Spool -> Runner -> Gate -> Cavity(제품)에 이르기까지의 Runner를 최소화하여 재용융을 위한 에너지의 비용 절감을 할 수가 있다. 금형 구조가 간단하므로 금형비가 저렴하여 다품종 소량생산에 매우 유리하다. 개발제품은 수직형 구조로 알루미늄 용탕의 윗면의 공기가 금형의 유로 상측에 위치하므로 공기(gas)가 먼저 배출되어 사출(주조)후 Rotor 성형부에 남아 있는 기포가 최소화된다. 그러므로 충진도가 높아진다. Rotor 코아(규소강)가 크더라도 수직형은 금형내에 삽입(Inset)하기가 쉽고 또한, 제품의 착탈 부위와 사출부위가 다르기 때문에 작업성, 안전성이 우수하고 생산성이 매우 높다. 수직형은 충진 밀도가 매우 높고 밀도가 균일하기 때문 Rotor의 회전 소음, 진동에 대한 품질이 매우 우수하다. 따라서 고효율, 고품질의 전동모터 Rotor 제품 생산에 매우 효과적인 장비라 할 수 있다.

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Behavior of Tension Clamp in Rail Fastening System (레일 체결장치 텐션클램프의 거동)

  • Choi, Shin-Hyung;Park, Beom-Ho;Yun, Kyung-Min;Bae, Hyun-Ung;Lim, Nam-Hyoung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.12
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    • pp.8812-8819
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    • 2015
  • In a situation in which importance of rail fastening system is growing with increasing the construction of concrete track, an accident of tension clamp(the component of rail fastening system) breaking has been recently occurred. This results from various factors such as field condition, operating agency, running condition, traffic frequency and so on. Thus, the study for the behavior of tension clamp is required. In this paper, an experiment and finite element analysis(FEA) have been performed to analyse the mechanical behavior of tension clamp. The stress and displacement of tension clamp have been analyzed as the clamping force through a laboratory test, and they were compared with FEA results. Furthermore, the stress and displacement of the tension clamp are derived from train load condition applying the verified model, and the fatigue vulnerability of the tension clamp is identified through stress analysis.

Prediction of Fretting Fatigue Life for Lap Joint Structures of Aircraft (항공기 겹침이음 조립구조의 프레팅 피로수명 예측)

  • Kwon, Jung-Ho;Joo, Seon-Yeong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.7
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    • pp.642-652
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    • 2009
  • Most of lap jointed aircraft structures encounter the fretting damages, which provoke fretting cracks prematurely and lead to significant reduction of fatigue life. In the case of ageing aircrafts especially, this fretting fatigue problem is a fatal threat for the safety and airworthiness. Recently, as the service life extension program(SLEP) of ageing aircrafts has become a hot issue, the prediction of fretting fatigue life is also indispensable. On these backgrounds, a series of experimental tests of fretting fatigue on bolted lap joint specimens, were performed. And the fretting crack initiation and propagation life of each specimen were evaluated using existing and newly proposed prediction models with the fretting parameters obtained from the FEA results for elasto-plastic contact stress analyses. The validations of prediction models were also discussed, comparing the prediction results with experimental test ones.

Development of the Method for Inspecting the Clamping Force of Torque Shear Bolts Using the Electricity energy of Electric torque wrench (전동렌치 전기에너지를 이용한 토크쉬어볼트의 체결축력 검사기법 개발)

  • Lee, Hyeon-Ju;Nah, Hwan-Seon;Kim, Kang-Sik;Kim, Kang-Seok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.6
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    • pp.162-170
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    • 2010
  • The torque-coefficient of torque-shear type high-strength bolts is affected by the environmental factors, such as 'wet', 'rust', 'exposure to air' and workability during tightening high strength bolts. It is difficult to assume the direct tension induced into the bolt due to variation of torque-coefficient for torque-shear type high-strength bolts. Therefore, it is essential to measure tension loads of bolts and to verify the clamping force under construction. In this study, the manufacture of trial product was planned to identify the induced force into the bolts. The algorithm for a trial product was composed of the relation between electricity energy taken from torque shear wrench and tension force from hydraulic tension meter. The regression analysis equation to measure the direct tension was derived by statistical analysis using Minitab program. It is considered that the trial product is reliable tool to evaluate the tension force comparable to a commercial torque wrench.

Functional Verification of the Solar Panel Separation Mechanism for Pico-Class Satellite Applications Using Spring-loaded Pogo-pin (포고핀을 활용한 극초소형 위성용 태양전지판 분리장치의 기능검증)

  • Kim, Su-Hyeon;Jeon, Young-Hyeon;Kim, Hong-Rae;Oh, Hyun-Ung
    • Journal of Aerospace System Engineering
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    • v.12 no.5
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    • pp.69-75
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    • 2018
  • In this study, we proposed a nylon wire cutting-type solar panel separation mechanism for CubeSat applications using spring-loaded pogo-pins, which has been widely used as temporary electrical interface between two separate electronics. The mechanism proposed in this study has great advantages of higher holding capability, ability to constrain along in-plane and out-of-plane directions of solar panels, simplicity in tightening of nylon wire and synchronous separation of multiple panels. In addition, the pogo-pins used for the proposed mechanism act as electrical power interface, separation status switch and separation spring. In this study, the functionality of the proposed mechanism was validated through the separation tests with various number of nylon wire windings.