• Title, Summary, Keyword: large displacement effect

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Large displacement geometrically nonlinear finite element analysis of 3D Timoshenko fiber beam element

  • Hu, Zhengzhou;Wu, Minger
    • Structural Engineering and Mechanics
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    • v.51 no.4
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    • pp.601-625
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    • 2014
  • Based on continuum mechanics and the principle of virtual displacements, incremental total Lagrangian formulation (T.L.) and incremental updated Lagrangian formulation (U.L.) were presented. Both T.L. and U.L. considered the large displacement stiffness matrix, which was modified to be symmetrical matrix. According to the incremental updated Lagrangian formulation, small strain, large displacement, finite rotation of three dimensional Timoshenko fiber beam element tangent stiffness matrix was developed. Considering large displacement and finite rotation, a new type of tangent stiffness matrix of the beam element was developed. According to the basic assumption of plane section, the displacement field of an arbitrary fiber was presented in terms of nodal displacement of centroid of cross-area. In addition, shear deformation effect was taken account. Furthermore, a nonlinear finite element method program has been developed and several examples were tested to demonstrate the accuracy and generality of the three dimensional beam element.

A Basic Study of Displacement Measurement of Magnetic Bearing System Using Hall Effect Sensor (자기베어링 시스템에서의 변위측정을 위한 홀 효과 센서의 기초 연구)

  • Yang, J.H.;Jeong, G.G.;Jeong, H.H.;Son, S.K.
    • Journal of Power System Engineering
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    • v.11 no.2
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    • pp.72-76
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    • 2007
  • Since the magnetic bearing system has unstability inherently it is necessary to measure the displacement for stable operation. Normally the displacement measurement is implemented by using sensors. The sensor for the displacement measurement is selected by precision, installation space, effect of magnetic field and response speed. And the cost of displacement measurement sensor also is considered. At the cost the hall effect sensor has a large advantage comparing with the others. Therefore this study concern about the basis experimental test for the displacement measurement of the magnetic bearing system that uses the hall effect sensor coupled with a tiny permanent magnet. The experimental results confirm the validity and practicability for this displacement measurement sensor.

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Design feasibility of double-skinned composite tubular wind turbine tower

  • Han, Taek Hee;Park, Young Hyun;Won, Deokhee;Lee, Joo-Ha
    • Wind and Structures
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    • v.21 no.6
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    • pp.727-753
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    • 2015
  • A double-skinned composite tubular (DSCT) wind power tower was suggested and automatic section design software was developed. The developed software adopted the nonlinear material model and the nonlinear column model. If the outer diameter, material properties and design capacities of a DSCT wind power tower are given, the developed software performs axial force-bending moment interaction analyses for hundreds of sections of the tower and suggests ten optimized cross-sectional designs. In this study, 80 sections of DSCT wind power towers were designed for 3.6 MW and 5.0 MW turbines. Moreover, the performances of the 80 designed sections were analyzed with and without considerations of large displacement effect. In designing and analyzing them, the material nonlinearity and the confining effect of concrete were considered. The comparison of the analysis results showed the moment capacity loss of the wind power tower by the mass of the turbine is significant and the large displacement effect should be considered for the safe design of the wind power tower.

Electroactive Paper Actuator: Principle and Its Application Possibility (생체모방 종이구동기의 원리 및 응용 가능성)

  • 윤성률;정우철;강유근;김재환
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.11
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    • pp.971-975
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    • 2004
  • This paper deals with the idea of Electroactive paper (EAPap) actuator and its application possibility. EAPap is a paper that produces large displacement under electrical excitation. EAPap is made with a cellulose paper by constructing thin electrodes on both sides of the paper. When electrical voltage is applied on the electrodes, the EAPap produces bending displacement. EAPap has merits in terms of lightweight, dryness, large displacement output, low actuation voltage and low power consumption. Since the power requirement is so small that it is suitable for microwave-driven smart actuators. This paper describes the working principle and performance of EAPap as an artificial muscle and its possibility far many applications.

Numerical modelling of nonlinear behaviour of prestressed concrete continuous beams

  • Lou, Tiejiong;Lopes, Sergio M.R.;Lopes, Adelino V.
    • Computers and Concrete
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    • v.15 no.3
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    • pp.373-389
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    • 2015
  • The development of a finite element model for the geometric and material nonlinear analysis of bonded prestressed concrete continuous beams is presented. The nonlinear geometric effect is introduced by the coupling of axial and flexural fields. A layered approach is applied so as to consider different material properties across the depth of a cross section. The proposed method of analysis is formulated based on the Euler-Bernoulli beam theory. According to the total Lagrangian description, the constructed stiffness matrix consists of three components, namely, the material stiffness matrix reflecting the nonlinear material effect, the geometric stiffness matrix reflecting the nonlinear geometric effect and the large displacement stiffness matrix reflecting the large displacement effect. The analysis is capable of predicting the nonlinear behaviour of bonded prestressed concrete continuous beams over the entire loading stage up to failure. Some numerical examples are presented to demonstrate the validity and applicability of the proposed model.

A Study on the Thermal Characteristics of Spindle for the Spinning Machine (스피닝 머신용 대형주축의 열특성에 관한 연구)

  • Jeong D.S.;Kim S.T.;Choi D.B.;Ye S.B.;Seol S.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.555-559
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    • 2005
  • Spinning process is a chipless metal forming method for axis-symmetric parts, which is more economical, efficient and versatile method for producing parts than other sheet metal forming process such as stamping or deep drawing. The large-sized spindle for spinning machine is the equipment to ferm a high-pressure vessel into the demanded shape. The important problem in the spindle system fur spinning machines is to reduce and minimize the thermal effect by motor and bearings. In this study, the effect of heat generation of bearings for the large-sized spindle is considered. Temperature distribution and thermal displacement of the spindle system for spinning machine can be analyzed by using the finite element method. The numerical results are compared with the measured data. The results show that temperature distribution and thermal displacement can be reasonably estimated by using the finite element method and the three dimensional model.

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Theoretical Analysis of Levers in a Precision Stage for Large Displacement (정밀 스테이지에서 출력변위 확대를 위한 레버의 해석)

  • 황은주;민경석;송신형;최우천
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.720-723
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    • 2004
  • Lever mechanisms are usually employed to enlarge output displacement in precision stages. In this study, theoretical analysis of a lever is presented including bending effect and relation between dimension parameters and an objective function. The objective function is chosen as multiplication of magnification ratio and forcedisplacement transmission. Through theoretical analysis, this study presents optimal values for the parameters and the analysis is verified by finite element method.

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Development and experimental study on cable-sliding modular expansion joints

  • Gao, Kang;Yuan, Wan C.;Dang, Xin Z.
    • Structural Engineering and Mechanics
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    • v.61 no.6
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    • pp.795-806
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    • 2017
  • According to the characteristics of continuous beam bridges, the relative displacement is too large to collision or even girder falling under earthquakes. A device named Cable-sliding Modular Expansion Joints(CMEJs) that can control the relative displacement and avoid collision under different ground motions is proposed. Working principle and mechanical model is described. This paper design the CMEJs, establish the restoring force model, verify the force model of this device by the pseudo-static tests, and describe and analyze results of the tests, and then based on a triple continuous beam bridge that has different heights of piers, a 3D model with or without CMEJs were established under Conventional System (CS) and Seismic Isolation System (SIS). The results show that this device can control the relative displacement and avoid collisions. The combination of isolation technology and CMEJs can be more effective to achieve both functions, but it need to take measures to prevent girder falling due to the displacement between pier and beam under large earthquakes.

Load-Displacement Characteristics Study of Barrette Pile by Bi-directional Loading Test (양방향재하시험을 통한 바렛말뚝의 하중-침하특성 연구)

  • Lim, Dae-Sung;Park, Seong-Wan;Lee, Sang-Rae
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.754-759
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    • 2008
  • Recently, the construction of buildings and large bridges has been increasing rapidly causing foundation structure growing larger then before, especially in the use of large size cast-in-place piles. Barrette Pile will usually be used at the site where diaphragm wall is the retaining wall to save time and cost in mobilization of equipments. This study uses bi-directional loading test data obtained from two different sites to observe the bearing capacity and displacement characteristics of barrette pile. Numerical analysis of the test is done by using commercial 3D computer program and the interface effect and capacity of the pile as well as displacement characteristics of the pile is verified.

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Applications of Displacement Response Estimation Algorithm Using Mode Decomposition Technique to Existing Bridges (모드분해기법을 이용한 변위응답추정 알고리즘의 실교량 적용)

  • Chang, Sung-Jin;Kim, Nam-Sik
    • Journal of The Korean Society of Civil Engineers
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    • v.30 no.3A
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    • pp.257-264
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    • 2010
  • Generally, estimations on the displacement as an important factor in evaluating the safety of large structures could be a barometer assessing whether the condition of the structure is deteriorating. Practically, it is not easy how to measure the displacement response to large structures like suspension bridges. In this study, as a method for estimation displacement response from strain signals, mode decomposition technique is proposed. Total displacement response is estimated by superposing quasistatic displacement response and modal displacement responses in dominant modes with larger contributions after estimating the modal displacement responses. If foiled strain gauges are used to measure strain signals, there would likely to generate electric noise, what's more, the more measuring points there are the more economic burden it could be. In order to solve such problems, fiber optic bragg-grating(FBG) sensors were used, which have multi-point measurements with no effect on electric noises. Therefore, the experiment was performed through dynamic load test of suspension bridge and plate-girder bridge to review the possibility for using mode decomposition technique.