• Title, Summary, Keyword: Slip Form

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Comparison of Concrete Setting Properties for the Application of Tapered Slip-Form method (변단면 슬립폼 공법 적용을 위한 콘크리트의 응결 특성 비교)

  • Song, Yong-Soon;Yang, Woo-Yong;Jung, Gil-Su;Seo, Young-Hwa
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.459-460
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    • 2010
  • For the application of slip form method to the pylon of Yi Sun-shin bridge which has much variation in its cross section, the change of setting properties of concrete due to changing weather and long pumping distance has to be taken into consideration. Different setting properties of several types of cement according to the amount of compound and ambient temperature were observed in this paper.

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INFLUENCE OF SLIP CONDITION ON RADIATIVE MHD FLOW OF A VISCOUS FLUID IN A PARALLEL POROUS PLATE CHANNEL IN PRESENCE OF HEAT ABSORPTION AND CHEMICAL REACTION.

  • VENKATESWARLU, M.;VENKATA LAKSHMI, D.;DARMAIAH, G.
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.20 no.4
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    • pp.333-354
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    • 2016
  • The present investigation deals, heat and mass transfer characteristics with the effect of slip on the hydromagnetic pulsatile flow through a parallel plate channel filled with saturated porous medium. Based on the pulsatile flow nature, exact solution of the governing equations for the fluid velocity, temperature and concentration are obtained by using two term perturbation technique subject to physically appropriate boundary conditions. The expressions of skin friction, Nusselt number and Sherwood number are also derived. The numerical values of the fluid velocity, temperature and concentration are displayed graphically whereas those of shear stress, rate of heat transfer and rate of mass transfer at the plate are presented in tabular form for various values of pertinent flow parameters. By increasing the slip parameter at the cold wall the velocity increases whereas the effect is totally reversed in the case of shear stress at the cold wall.

Development of Tactile Sensor for Detecting Contact Force and Slip (접촉력 및 미끄러짐을 감지 가능한 촉각 센서의 개발)

  • Choi Byung-June;Kang Sung-Chul;Choi Hyouk-Ryeol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.4
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    • pp.364-372
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    • 2006
  • In this paper, we present a finger tip tactile sensor which can detect contact normal force as well as slip. The sensor is made up of two different materials, such as polyvinylidene fluoride (PVDF) known as piezoelectric polymer, and pressure variable resistor ink. In order to detect slip on the surface of the object, two PVDF strips are arranged along the normal direction in the robot finger tip and the thumb tip. The surface electrode of the PVDF strip is fabricated using silk-screening technique with silver paste. Also a thin flexible force sensor is fabricated in the form of a matrix using pressure variable resistor ink in order to sense the static force. The developed tactile sensor is physically flexible and it can be deformed three-dimensionally to any shape so that it can be placed on anywhere on the curved surface. In addition, a tactile sensing system is developed, which includes miniaturized charge amplifier to amplify the small signal from the sensor, and the fast signal processing unit. The sensor system is evaluated experimentally and its effectiveness is validated.

Three-Dimensional Steady-state Rolling Contact Analysis using Finite Element Method (3차원 유한요소법을 이용한 정상상태의 구름접촉해석)

  • Lee, Dong-Hyong;Seo, Jung-Won;Kwon, Seok-Jin;Ham, Young-Sam
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.5
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    • pp.565-571
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    • 2011
  • Because most fatigue cracks in wheel and rail take place by rolling contact of wheel and rail in railroad industry, it is critical to understand the rolling contact phenomena, especially for the three-dimensional situation. This paper presents an approach to steady-state rolling contact problem of three-dimensional contact bodies, with or without tangential force, based on the finite element method. The steady-state conditions are controlled by the applied relative slip and tangential force. The three-dimensional distribution of tangential traction and contact stresses on the contact surface are investigated. Results show that the distribution of tangential traction and contact stresses on the contact surface varies rapidly as a result of the variation of stick-slip region. The tangential traction is very close in form to Carter's distribution.

An analytical analysis of the pullout behaviour of reinforcements of MSE structures

  • Ren, Feifan;Wang, Guan;Ye, Bin
    • Geomechanics and Engineering
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    • v.14 no.3
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    • pp.233-240
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    • 2018
  • Pullout tests are usually employed to determine the ultimate bearing capacity of reinforced soil, and the load-displacement curve can be obtained easily. This paper presents an analytical solution for predicting the full-range mechanical behavior of a buried planar reinforcement subjected to pullout based on a bi-linear bond-slip model. The full-range behavior consists of three consecutive stages: elastic stage, elastic-plastic stage and debonding stage. For each stage, closed-form solutions for the load-displacement relationship, the interfacial slip distribution, the interfacial shear stress distribution and the axial stress distribution along the planar reinforcement were derived. The ultimate load and the effective bond length were also obtained. Then the analytical model was calibrated and validated against three pullout experimental tests. The predicted load-displacement curves as well as the internal displacement distribution are in closed agreement with test results. Moreover, a parametric study on the effect of anchorage length, reinforcement axial stiffness, interfacial shear stiffness and interfacial shear strength is also presented, providing insights into the pullout behaviour of planar reinforcements of MSE structures.

Pulse response characteristics and preparation of piezoelectic composite materials with 1-3 connectivity (1-3형 압전복합재료의 제조 및 펄스응답특성)

  • 김진수;김용혁;김호기;이덕출
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.77-80
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    • 1989
  • The aim of the study is to develope the processing technique of PZT-Polymer piezoelectric composite materials for ultrasonic transducer application such as biomedical probe and hydrophone. Piezoelectric composite of PZT and polymer with 1-3 connectivity patterns have been fabricated by dicing-filling method and extrusion forming method. In this study processing forming method. In the study processing steps by extrusion forming method in the preperation of PZT/polymer piezoelectric composites are described. The PZT powder used in the study is commercial powder which is prepared by mixing PbO, TiO$_2$ and ZrO$_2$. The binder, water and plasticizer are mixed with the PZT powder to form a slip. It is necessary to adjust the viescosity of slip according on the PZT rod diameters to be extruded. The electromechanical properties of the piezoelectric composites are characterized in terms of the thickness resonance mode. The pulse response characteristics by the ultrasonic transducer analyzer and osciloscope are evaluated.

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A Comparison of a Lagrangian Vortex Method with a Finite Volume Method for the Vorticity-Velocity Formulation. (와도-속도 정식화에서 Lagrangian 보오텍스법과 유한체적법의 비교)

  • Kim Kwang-Soo;Lee Seung-Jae;Suh Jung-Chun
    • 한국전산유체공학회:학술대회논문집
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    • pp.47-52
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    • 2002
  • We present an improved Lagrangian vortex method in 2-D incompressible unsteady viscous flows, which is based on a mesh-free integral approach of the velocity-vorticity formulation. Vorticity fields are represented by discrete vortex blobs that are updated by the Lagrangian vorticity transport with the particle strength exchange scheme. Velocity fields are expressed in a form of the Helmholtz decomposition, which are calculated by a fast algorithm of the Biot-Savart integration with a smoothed kernel and by a well-established panel method. No-slip condition is enforced through viscous diffusion of vorticity from a solid body into field. The vorticity flux is determined in such a way that spurious slip velocity vanishes. Through the comparison with the existing finite volume scheme for the transient vortical flows around an impulsively started cylinder at Reynolds number Re=550, we would obtain a more accurate scheme for vortex methods in complicated flows.

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A Study on the ECU and Control Algorithm of ABS for a Commercial Vehicle

  • Lee, Ki-Chang;Kim, Mun-Sub;Jeon, Jeong-Woo;Hwang, Don-Ha;Park, Doh-Young;Kim, Yong-Joo
    • 제어로봇시스템학회:학술대회논문집
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    • pp.166.1-166
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    • 2001
  • Anti-lock Braking System(ABS) is a device which prevents the wheels form locked up under emergency braking of a vehicle. So it helps the vehicle to maintain the steerability and shortens the braking distance by maintaining optimal frictional force during braking since the tire road slip is controlled in acceptable range. Recently, ABS is accepted as a standard equipment in vehicles, especially in commercial vehicles(bus and trucks). Commercial vehicles don´t use hydraulic lines but use pneumatic lines for braking system mostly. In this paper, ECU(Electronic Control Unit) for the anti-lock braking system of a commercial vehicle which is equipped with a full-air brake system and its control algorithms are presented. In this algorithm wheel speed acceleration flags and wheel slip flags are defined ...

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