• Title/Summary/Keyword: Force transmission ratio

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Development of Nonlinear Analysis Technic to Determine the Ultimate Load in Electric Transmission Tower (송전철탑의 극한하중 도출을 위한 비선형해석 기법)

  • Kim, Woo Bum;Choi, Byong Jeong;Ahn, Jin Kyu
    • Journal of Korean Society of Steel Construction
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    • v.20 no.3
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    • pp.389-398
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    • 2008
  • The current design practice of electric transmission tower is based on the allowable stress design. However, it is difficult to find the cause behind a transmission tower's collapse by the above design approach as the collapse is caused by large secondary deformations based on and geometrical nonlinear behavior.influence factor for the nonlinear behavior is mainly residual stress, initial imperfection and end restraints on members. In this study, the necessity of the nonlinear analysis is examined through the comparison between elastic ana the nonlinear analysis, a new analytical method (equivalent nonlinear analysis technique) is proposed. To confirm the reliability of the proposed method, the computed ultimate load of the transmission tower using the method was compared with that of the nonlinear finite element analysis. Effects of parameters, such as compressive force and the slenderness ratio of the brace member on the main post member, were investigated. The effective member length according to influential parameters was formulated in table form for practical purposes.

Nonlinear Analysis of Mixed Structure with Connection Slip (슬립을 고려한 혼합구조 접합부의 비선형 해석)

  • Sung Jae-Jin;Huh Taik-Nyung;Lee Yoon-Soo;Cho Sung-Yong
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.615-622
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    • 2006
  • As construction technique and design are developing, the bridge tend to be longer, and also the type of bridge is verity. Steel and concrete combination improve the mechanics characteristic and economical efficient which Hybrid Structure divide Mixed Structure with Composite Structure. The connected section of the Mixed Structure should integrate steel and concrete that should show the same behavior as well, And also this connection needs big interna1 force and stiffness because it used to be a most dangerous section. This study carry out a nonlinear analysis technique with slip, check out each different type of section force's transfer mechanism on the connection. And this analysis was carried out using parameter that are front plate thickness, connection length, filled concrete strength and so on. We confirmed the profitable type of connection is front backward type. The biggest stiffness and certain stress transmission are showed at the ratio 0.075 between total length and connection length, and also most economical front plate thickness is judged when it set three times thicker than flange.

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Development of Exoskeleton-Type Data Glove for Position/Force Feedback (위치/힘 피드백이 가능한 외골격 구조의 데이터 글로브 개발)

  • Kim, Min-Jeong;Kim, Dae-Gyeong;Park, Han-Gil;Kim, Ui-Kyum;Choi, Byung-June;Choi, Hyouk-Ryeol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.12
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    • pp.1585-1591
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    • 2011
  • In this paper, we present a new exoskeleton-type data glove that can sense the movement of the human finger and reflect the force to the finger. The data glove is designed on the basis of the skeletal structure of the human hand, and the finger module has 1 degree-of-freedom because it includes three four-bar mechanism joints in series and a wire-coupling mechanism. In addition, the transmission ratio of the finger module is maintained at 1:1.4:1 over the entire movement range, and hence, the module can perform both extension and flexion. In addition, to enable adduction/abduction motion of the human hand, a unique MCP joint is designed by using two universal joints. To validate the feasibility of the data glove, master-slave control experiments based on force-position control between the data glove and the robot hand are conducted.

Studies on Development of Fuel Substitute for Diesel Engine with Seed Oil of Evodia Daniellii (쉬나무 종실유의 디젤기관 대체연료 개발에 관한 연구 - Engine 성능 및 견인력을 중심으로 -)

  • Choi, Kyu-Hong;Hong, Sung-Gak;Lee, Yeo-Ha;Lee, Seung-Kee;Shin, Seung-Geuk
    • Journal of Korea Foresty Energy
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    • v.7 no.1
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    • pp.28-36
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    • 1987
  • To know the possibility of fuel substitution for Diesel engine with the seed oil of Evodia daniellii, which is one of the native oil seed trees in Korea. the refined seed oil mixed with light oil in the various rates was tested in the 8 PS Diesel engine: the output, the fuel consumption rate, the governor performance, the rpm stability in the total loading condition. the content of graphite in the burned gas, and the traction coefficients at the different gear stages were maintained The following results were discussed. 1. The output at the normal revolution (2200rpm)was increased as the percent seed oil increased. At the lower rpm (2000-1500rpm )there were no consistent difference in the outputs among fuels of the different percent seed oil 2. The rate of fuel consumption was inclosed as the percent seed oil increased in each loading condition. 3. The more percent sud oil was mixed in the fuel. the better governor performance appeared at both the instantaneous and stable speed. 4. The more percent seed oil was mixed In the fuel, the more stable rpm ratio was maintained 5. The graphite content In the burned gas was increased as the load increased, but there was no apparent difference in the content at each load among the 100$\%$ seed oil, the 100$\%$ light oil, and the mixtures in various rates. 6. In all fuel mixtures the maximam traction coefficent appeared at the third transmission gear stage. Generally in over all transmission gear stages the fuel mixtures of the seed oil:light oil ratio from 7:3 to 5:5 resulted greater traction force than the other fuels.

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ACCB- Adaptive Congestion Control with backoff Algorithm for CoAP

  • Deshmukh, Sneha;Raisinghani, Vijay T.
    • International Journal of Computer Science & Network Security
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    • v.22 no.10
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    • pp.191-200
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    • 2022
  • Constrained Application Protocol (CoAP) is a standardized protocol by the Internet Engineering Task Force (IETF) for the Internet of things (IoT). IoT devices have limited computation power, memory, and connectivity capabilities. One of the significant problems in IoT networks is congestion control. The CoAP standard has an exponential backoff congestion control mechanism, which may not be adequate for all IoT applications. Each IoT application would have different characteristics, requiring a novel algorithm to handle congestion in the IoT network. Unnecessary retransmissions, and packet collisions, caused due to lossy links and higher packet error rates, lead to congestion in the IoT network. This paper presents an adaptive congestion control protocol for CoAP, Adaptive Congestion Control with a Backoff algorithm (ACCB). AACB is an extension to our earlier protocol AdCoCoA. The proposed algorithm estimates RTT, RTTVAR, and RTO using dynamic factors instead of fixed values. Also, the backoff mechanism has dynamic factors to estimate the RTO value on retransmissions. This dynamic adaptation helps to improve CoAP performance and reduce retransmissions. The results show ACCB has significantly higher goodput (49.5%, 436.5%, 312.7%), packet delivery ratio (10.1%, 56%, 23.3%), and transmission rate (37.7%, 265%, 175.3%); compare to CoAP, CoCoA+ and AdCoCoA respectively in linear scenario. The results show ACCB has significantly higher goodput (60.5%, 482%,202.1%), packet delivery ratio (7.6%, 60.6%, 26%), and transmission rate (40.9%, 284%, 146.45%); compare to CoAP, CoCoA+ and AdCoCoA respectively in random walk scenario. ACCB has similar retransmission index compare to CoAp, CoCoA+ and AdCoCoA respectively in both the scenarios.

Analysis of Planocentric Gear

  • Kim, H.J.
    • Agricultural and Biosystems Engineering
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    • v.7 no.1
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    • pp.13-17
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    • 2006
  • The planocentric gear, known as wobble mechanism, has been used for speed reducing mechanism as an ingenious mechanism. The modem application can be found in the backrest adjusting mechanism of a vehicle reclinable seat, fluid pumps and aircraft hoist and winches. Higher speed reduction ratios, high load capacity, lower weight, and compactness are the main advantages of this gear. This paper presents velocity and static force analysis to investigate the friction lock of the planocentric gear. The rectilinear tooth profile is used to maximize the speed reduction ratio. The equivalent linkage system is used for the analysis of instantaneous motion. As the results, the transmission efficiency of the planocentric gear is found and the friction lock of the system is determined for the friction coefficients of journals. A numerical example that illustrates the developed analysis is presented.

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Structureborne Noise Transfer Analysis Using Pole Parameter Method for Resiliently Mounted Equipment (절점 해석 기법을 이용한 탄성지지 장비 시스템의 고체음 전달 해석)

  • Choi, Tae-Muk;Kim, Tae-Suk;Cho, Dae-Seung;Chung, Jung-Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.398-402
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    • 2005
  • Structureborne noise induced by shipboard equipment is one of the most significant noise source of ships and can be effectively reduced by resiliently mounting them. In this paper, the pole parameter method is investigated for estimating the structureborne noise reduction of resiliently mounted equipment. In addition, we suggest how to evaluate pole parameters from dimensional and material information of each component consisting of resiliently mounted equipment. To validate and discuss the proposed method numerical analysis for single and double resiliently mounted equipment systems using both pole parameter method and FEM have been done.

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The Design and Actuator Sizing for Redundantly Actuated Omni-Directional Mobile Robot

  • Park, Tae-Bum;Yi, Jae-Hoon;Yi, Byung-Ju;Kim, Whea-Kuk;Yu, Bum-Jae;Oh, Sang-Rok
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.137.4-137
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    • 2001
  • Omni-directional mobile robots have been employed popularly in several application areas. However, the optimal design has not been considered yet. This paper introduces an optimal design methodology for omni-directional mobile robots. Optimal design parameters such as the offset distance and the wheel radius are identified with respect to isotropy. Furthermore, the force transmission ratio and actuator sizing problem are treated. Conclusivel, three cases are compared minimum actuation, two active caster wheel, and three active caster wheel, we claim that the redundantly actuated mobile robot with three active caster wheel has the best performance.

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Kinematic optimal design and analysis of kinematic/dynamic performances of a 3 degree-of-freedom excavator subsystem (3 자유도 굴착기 부속 시스템의 기구학적 최적 설계와 기구학/동력학 성능 해석)

  • Kim, Whee-Kuk;Han, Dong-Young;Yi, Byung-Ju
    • Journal of Institute of Control, Robotics and Systems
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    • v.3 no.4
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    • pp.422-434
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    • 1997
  • In this paper, a two-stage kinematic optimal design for a 3 degree of-freedom (DOF) excavator subsystem, which consists of boom, arm and bucket, is performed. The objective of the first stage is to find the optimal parameters of the joint-actuating mechanisms which maximize the force-torque transmission ratio between the hydraulic actuator and the rotating joint. The objective of the second stage is to find the optimal link parameters which maximize the isotropic characteristic of the excavator subsystem throughout the workspace. It is illustrated that kinematic/dynamic performances of the kinematically optimized excavator subsystem have improved compared to those of original HE280 excavator, with respect to three performance indices such as maximum load handling capacity, maximum velocity capability, and acceleration capability.

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The Development of Gradient Response CVT for a Small Size Electric Vehicle (소형 전기차량용 구배반응 무단변속기 개발)

  • Kim, Gyu-Sung;Kwon, Young-Woong
    • Journal of Power System Engineering
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    • v.19 no.6
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    • pp.33-38
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    • 2015
  • In this study new CVT(Continuously Variable Transmission) system which is adaptable to a small size electric vehicle is proposed available to gradient response CVT. New pulleys consist of springs adapted driving pulley and driven pulley. At the moment a small electric vehicle drive a slope, new system respond to a gradient as overcoming tensional force of springs. We made prototype of gradient response CVT to test parts performance and travelling performance test. As a result of test, belt pitch diameter varied for high torque direction at the gradient. In the flat travelling, acceleration travelling and gradient travelling performance test, the small electric vehicle with gradient response CVT get improved perfomance than the small electric vehicle with reduction gear.