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Performance Verification of Separation Nut Type Non-explosive Separation Device for Cube Satellite Application (큐브위성 적용을 위한 분리너트형 비폭발식 구속분리장치 인증모델의 성능검증)

  • Oh, Hyun-Ung;Lee, Myeong-Jae
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.10
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    • pp.827-832
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    • 2013
  • Heating wire cutting type separation mechanism has been widely used for cube satellite applications due to its design constraints such as small size of $10cm{\times}10cm{\times}10cm$ and light weight of less than 1kg. In addition, usage of pyro technic device is not allowed for cube satellite application. The conventional methods have some disadvantages of relatively small mechanical constraint force and the system complexity for the multi-deployable systems. In this paper, a separation nut type non-explosive separation mechanism has been proposed and investigated. The effectiveness of the design has been verified through the qualification tests of the mechanism.

Effect of Powerlock Inner Ring Shape, Bolt-fastening Force, and Friction on Power Transmission Performance (파워록 형상 및 마찰이 동력전달 성능에 미치는 영향 분석)

  • Kim, Dae Rae;Jang, Yeon-Hui;Jang, Myung-Geun;Park, Jin-Ah;Kim, Jong-Bong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.3
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    • pp.241-249
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    • 2017
  • A powerlock is used to transmit torque between two shafts, to protect important equipment from overloads, and to compensate for the misalignment of assembled shafts. In this study, the effect of the shapes of the inner rings, bolt-fastening force, and friction on power transmission performance of powerlocks is investigated. Finite element analysis and experiments were conducted for two cases, and the analysis results were validated. Analyses were carried out for inner rings of various shapes and for various values of bolt-fastening force and friction coefficient. The main factors that affect the torque transmission performance were investigated based on the analysis results.

Estimation on Clamping Force of High Strength Bolts Considering Temperature Variable of Both Site conditions and Indoor Environments (실내환경과 건설현장 온도변수를 고려한 고력볼트 체결력 예측)

  • Nah, Hwan-Seon;Lee, Hyeon-Ju
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.6 no.3
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    • pp.32-40
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    • 2015
  • The torque shear high strength bolt is clamped normally at the break of pin-tail specified. However, the clamping forces on slip critical connections do not often meet the required tension, as it considerably fluctuates due to torque coefficient dependent on lubricant affected temperature. In this study, the clamping tests of torque shear bolts were conducted independently at indoor conditions and at construction site conditions. During last six years, temperature of candidated site conditions was recorded from $-11^{\circ}C$ to $34^{\circ}C$. The indoor temperature condition was ranged from $-10^{\circ}C$ to $50^{\circ}C$ at each $10^{\circ}C$ interval. As for site conditions, the clamping force was reached in the range from 159 to 210 kN and the torque value was from 405 to $556 N{\cdot}m$. The range of torque coefficient at indoor conditions was analyzed from 0.126 to 0.158 while tensions were indicated from 179 to 192 kN. The torque coefficient at site conditions was ranged from 0.118 to 0.152. Based on this test, the variable trends of torque coefficient, tension subjected temperature can be taken by statistic regressive analysis. The variable of torque coefficient under the indoor conditions is $0.13%/^{\circ}C$ while it reaches $2.73%/^{\circ}C$ at actual site conditions. When the indoor trends and site conditions is combined, the modified variable of torque coefficient can be expected as $0.2%/^{\circ}C$. and the modified variable of tension can be determined as $0.18%/^{\circ}C$.

Structural Design of Cube Satellite by Using Heating Wire Cutting Type Separation Mechanism (열선절단방식 구속분리장치를 적용한 큐브위성의 구조설계)

  • Oh, Hyun-Ung;Kwon, Sung-Cheol
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.9
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    • pp.720-725
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    • 2013
  • Nylon wire cutting method by nichrome wire is generally applicable for cube satellite applications due to its advantages of simplicity. However, the system complexity is not avoidable to apply it on the cube satellite with multi-deployable structures. A lower constraint force of the mechanism is also one of the disadvantages of the mechanism. In this study, we proposed a preliminary structure design of cube satellite with the separation mechanism which is applicable for holding and release of the multi-deployable structures. The effectiveness of the mechanism design was verified through function test of EM mechanism. The structure analysis results showed that the structure design proposed in this study is feasible.

Molding Analysis for the Production of Large Sun Visors in Vehicles (차량용 대형 선바이저 생산을 위한 성형해석)

  • Park, Jong-Nam;Noh, Seung-Hee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.11
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    • pp.610-615
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    • 2016
  • Diverse accessories are used in automobiles, such as navigation systems, front and rear cameras, spoilers, and sun visors. Sun visors block sunlight so that drivers can drive safely with a better view, and they are used in many automobile designs. However, when large plastic products are manufactured using injection molding, there are many difficulties that develop, like weld lines, short shots, flow marks, imperfections, and distortion. In this study, a CAE simulation was conducted based on previous results to predict potential problems in the injection molding of large products. The flow characteristics up to complete charge for the melting resins were captured using a computer-aided engineering simulation. The temperature departure on the front part of a flow was about $10^{\circ}C$ and very stable. The practical ejecting time of the cold runner was about 70 seconds in the simulation. Finally, the capability of a suitable injection machine was calculated and recommended by prediction of the injection pressure and the die clamping force.

Hysteresis Behavior of Partially Restrained Smart Connections for the Seismic Performance of Composite Frame (CFT 합성골조의 내진성능을 위한 스마트 반강접합의 이력거동)

  • Kim, Joo Woo
    • Journal of Korean Society of Steel Construction
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    • v.27 no.1
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    • pp.99-108
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    • 2015
  • The partially restrained smart CFT (concrete filled tube) column-to-beam connections with top-seat split T connections show various behavior characteristics according to the changes in the diameter and tightening force of the fastener, the geometric shape of T-stub, and material properties. This paper presents results from a systematic three-dimensional nonlinear finite element study on the structural behavior of the top-seat split T connections subjected to cyclic loadings. This connection includes super-elastic shape memory alloy (SMA) T-stub and rods to obtain the re-centering capabilities as well as great energy dissipation properties of the CFT composite frame. A wide scope of additional structural behaviors explain the influences of the top-seat split T connections parameters, such as the different thickness and gage distances of split T-stub.

Effect of Clearance on Clamping Characteristics of Segmented Nuts in Pyrotechnic Separation Nut (파이로테크닉 분리 너트 내부 분할 너트 체결 특성에 대한 틈새의 영향)

  • Woo, Jeongmin;Kang, Dahoon;Choi, Jaeyoung;Kim, Jeong Ho;Cho, Jin Yeon;Jang, Seung-gyo;Yang, Hee Won
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.12
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    • pp.994-1003
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    • 2018
  • The clamping characteristics of segmented nuts in pyrotechnic separation nut are investigated using finite element analysis. When the segmented nuts are used to clamp objects, a constraint cylinder is necessary to prevent the segmented nuts from spreading out to the radial direction. During the manufacturing process, a clearance is usually introduced between the outer diameter of the segmented nuts and the inner diameter of the constraint cylinder. Therefore to find out the effect of the clearance, proper finite element modeling method is suggested to describe the clamping procedure appropriately. In addition, finite element analysis with the clearance of 0.00, 0.03, 0.06, and 0.10 mm are performed. From the analysis results, the clamping characteristics of segmented nuts are investigated according to the clearance, and several factors which should be considered to design a reliable pyrotechnic separation nut are figured out.

Study for weight of wedge type rail clamp according to initial clamping force (레일클램프의 원활한 클램핑과 초기체결력 발휘를 위한 중추무게의 관계에 관한 연구)

  • Han, Geun-Jo;An, Chan-Woo;Kim, Tae-Hyung;Sim, Jae-Jun;Han, Dong-Sub;Lee, Ho;Jeon, Young-Hwan
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1517-1520
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    • 2003
  • In this paper, we design a wedge type rail-clamp which can protect container crane from wind with constant clamping force regardless of the operating period. When we design wedge type rail clamp, it is important to determine the weight for locker to descent smoothly with an initial clamping force of rail and pad. Therefor, this paper suggest a process to decide a wright within proper range which could be obtained using FEA of wedge type rail clamp.

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다이케스팅 머신의 구조 해석

  • 윤승원
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.813-817
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    • 1995
  • Structural analysis of horizontal cold chamber die casting machine is performed by the FEM. The analyzed model is made up of stationary die platen,movable die platen,link housing platen, C-frame, and tie bar which mainly undertake die locking force and injection force. In modeling, compression gap elements are used for to simulate contacting condition between tie bar and movable die platen, movable die platen and base frame, and link housing and base frame. Unbalanced die locking force imposed on four tie bars are considered. As the results, the deformed shape and the stresses of the die casting machine are given.

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Preliminary System Design of STEP Cube Lab. for Verification of Fundamental Space Technology (우주기반기술 검증용 극초소형 위성 STEP Cube Lab.의 시스템 개념설계)

  • Kwon, Sung-Cheol;Jung, Hyun-Mo;Ha, Heon-Woo;Han, Sung-Hyun;Lee, Myung-Jae;Jeon, Su-Hyeon;Park, Tae-Young;Kang, Su-Jin;Chae, Bong-Gun;Jang, Su-Eun;Oh, Hyun-Ung;Han, Sang-Hyuk;Choi, Gi-Hyuk
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.42 no.5
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    • pp.430-436
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    • 2014
  • The mission objective of STEP Cube Lab. (Cube Laboratory for Space Technology Experimental Project) classified as a pico-class satellite is to verify the technical effectiveness of payloads such as variable emittance radiator, SMA washer, oscillating heat pipe and MEMS based solid propellant thruster researched at domestic universities. In addition, the MEMS concentrating photovoltaic power system and the non-explosive holding and separation mechanism with the advantages of high constraint force and low shock level will be developed as the primary payloads for on-orbit verification. In this study, the feasibility of the mission actualization has been confirmed by the preliminary system design.