• Title, Summary, Keyword: Slip Form

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A Modified Shooting Method Technique for the Analysis of the Limited Slip Capacity of UHPFRC-NC Composite Structure

  • Han, Sang-Mook;Wu, Xiangguo;Kim, Sung-Wook;Kang, Su-Tae
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.1061-1064
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    • 2008
  • Shear connectors have a finite slip capacity because of the mechanism by which they transfer the shear between UHPFRC and NC elements. At high degree of shear connection, non-linear analysis techniques are required to allow for compressive plasticity and tensile cracking behaviour of the elements. As with all non-linear problems, a closed form solution is difficult to find. A Modified Shooting Method Technique is developed here for non-linear analysis of UHPFRC/concrete composite. The initial effective moment is derived according to the prestressing force. The composite structure is divided into small segments which length is much less than the length of the structure and it can be assumed that the forces and displacements within each segment are constant. An equivalent analysis in composite girders would be to fix the slip strain in each segment and develop a moment curvature relationship for this slip strain in each segment. Additive forces and moment analysis on each section of the segments are analyzed by MSMT. Finally the ultimate slippage of the interface can be evaluated by the MSMT model. This paper presents a nonlinear analysis method for limited slip capacity of UHPFRC-NC interface.

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DUFOUR AND HEAT SOURCE EFFECTS ON RADIATIVE MHD SLIP FLOW OF A VISCOUS FLUID IN A PARALLEL POROUS PLATE CHANNEL IN PRESENCE OF CHEMICAL REACTION

  • VENKATESWARLU, M.;BABU, R. VASU;SHAW, S.K. MOHIDDIN
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.21 no.4
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    • pp.245-275
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    • 2017
  • The present investigation deals, Dufour and heat source effects on radiative MHD slip flow of a viscous fluid in a parallel porous plate channel in presence of chemical reaction. The non-linear coupled partial differential equations are solved by using two term perturbation technique subject to physically appropriate boundary conditions. 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. It is observed that the effect of Dufour and heat source parameters decreases the velocity and temperature profiles.

A Study on The Material Selection and Characteristic Investigation of Rotor Bar and End Ring of Induction Motor for High Speed Train (고속전철용 견인전동기의 회전자 바와 엔드링의 재질선정 및 특성고찰에 관한 연구)

  • 이상우;김근웅;윤종학;이기호;한성수
    • Proceedings of the KSR Conference
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    • pp.187-193
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    • 1998
  • An inverter-driven induction motor is used as the traction motor for a high speed drive system that required safty, reliability and performance and so on. rotor bar and end ring of the traction motor are the electrical equipments which form the conductive close loop and then induce current by interaction wi th the current of stator. the materials selection of rotor bar and end ring are seriously considered in the aspects of electrical and mechanical specification and Motor slip relation to inverter. Particularly motor slip guarantee the safty and reliability of induction motor. this paper show the material selection and the determining of slip in the design of traction motor for high speed train by analyzing the specifications of material being used currently.

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Development of Fingertip Tactile Sensor for Detecting Normal Force and Slip

  • Choi, Byung-June;Kang, Sung-Chul;Choi, Hyouk-Ryeol
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1808-1813
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    • 2005
  • In this paper, we present the finger tip tactile sensor which can detect contact normal force as well as slip. The developed sensor is made of two different materials, such as polyvinylidene fluoride(PVDF) that is known as piezoelectric polymer and pressure variable resistor ink. In order to detect slip to surface of object, a PVDF strip is 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, we developed a tactile sensing system by miniaturizing the charge amplifier, in order 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.

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Experimental bond behavior of hybrid rods for concrete reinforcement

  • Nanni, Antonio;Nenninger, Jeremy S.;Ash, Kenneth D.;Liu, Judy
    • Structural Engineering and Mechanics
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    • v.5 no.4
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    • pp.339-353
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    • 1997
  • Fiber reinforced plastic (FRP) rods provide certain benefits over steel as concrete reinforcement, such as corrosion resistance, magnetic and electrical insulation, light weight, and high strength. FRP composites can be combined with a steel core to form hybrid reinforcing rods that take advantage of properties of both materials. The objective of this study was to characterize the bond behavior of hybrid FRP rods made with braided epoxy-impregnated aramid or poly-vinyl alcohol FRP skins. Eleven rod types were tested using two concrete strengths. Specific topics examined were bond strength, slip, and type of failure in concentric pull-out tests from concrete cubes. From analysis of identical pull-out tests on both hybrid and steel rods, information on relative bond strength and behavior were obtained. It is concluded that strength is similar but slip in hybrid rods is much higher. Hybrid rods failed either by pull-out or splitting the concrete block (with or without yielding of the steel core). Experimental data showed consistency with similar test results presented in the literature.

Finite Element Stress Analysis of Implant Prosthesis According to Friction Fit or Slip Fit of Internal Connection System between Implant and Abutment (임플랜트와 지대주 간 내측연결 시스템에서 Friction Fit와 Slip Fit에 따른 유한요소 응력분석)

  • Jang, Doo-Ik;Jeong, Seung-Mi;Chung, Chae-Heon
    • Journal of Dental Rehabilitation and Applied Science
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    • v.21 no.2
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    • pp.113-132
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    • 2005
  • The purpose of this study was to assess the stress-induced pattern at the supporting bone, the implant fixture, the abutment and the abutment screw according to a friction-fit joint (Astra; Model 1) or slip- fit joint (Frialit-2; Model 2) in the internal connection system under vertical and inclined loading using finite element analysis. In conclusion, in the internal connection system of the implant and the abutment connection methods, the stress-induced pattern at the supporting bone, the implant fixture, the abutment and the abutment screw according to the abutment connection form had difference among them, and the stress distribution pattern usually had a widely distributed tendency along the inner surface of the implant fixture contacting the abutment post. The magnitude of the stress distributed in the supporting bone, the implant fixture, the abutment and the abutment screw was higher in the friction-fit joint than in the slip-fit joint. But it is considered that the further study is necessary about how this difference in the magnitude of the stress have an effect on the practical clinic.

Control Method of Mobile Robots for Avoiding Slip and Turnover on Sloped Terrain Using a Gyro/Vision Sensor Module (Gyro/Vision Sensor Module을 이용한 주행 로봇의 미끄러짐 및 넘어짐 회피 제어 기법)

  • Lee Jeong-Hee;Park Jae-Byung;Lee Beom-Hee
    • Journal of Institute of Control, Robotics and Systems
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    • v.11 no.8
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    • pp.669-677
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    • 2005
  • This acticle describes the control method of mobile robots for avoiding slip and turnover on sloped terrain. An inexpensive gyro/vision sensor module is suggested for obtaining the information of terrain at present and future. Using the terrain information and the robot state, the maximum limit velocity of the forward velocity of the robot is defined fur avoiding slip and turnover of the robot. Simultaneously the maximum value of the robot velocity is reflected to an operator in the form of reflective force on a forte feedback joystick. Consequently the operator can recognize the maximum velocity of the robot determined by the terrain information and the robot state. In this point of view, the inconsistency of the robot movement and the user's command caused by the limit velocity of the robot can be compensated by the reflective force. The experimenal results show the effectiveness of the suggested method.

Finite Element Analysis of Powder Injection Molding Filling Process Including Yield Stress and Slip Phenomena (항복응력과 미끄럼현상을 고려한 분말사출성형 충전공정의 유한요소해석)

  • 박주배;권태헌
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.6
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    • pp.1465-1477
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    • 1993
  • Powder Injection Molding(PM) is an advanced and complicated technology for manufacturing ceramic or metal products making use of a conventional injection molding process, which is generally used for plastic products. Among many technologies involved in the successful PIM, injection molding process is one of the key steps to form a desired shape out of powder/binder mixtures. Thus, it is of great importance to have a numerical tool to predict the powder injection molding filling process. In this regard, a finite element analysis system has been developed for numerical simulations of filling process of powder injection molding. Powder/polymer mixtures during the filling pro cess of injection molding can be rheologically characterized as Non-Newtonian fluids with a so called yield phenomena and have a peculiar feature of apparent slip phenomena on the wall boundaries surrounding mold cavity. Therefore, in the present study, a physical modeling of the filling process of powder/polymer mixtures was developed to take into account both the yield stress and slip phenomena and a finite element formulation was developed accordingly. The numerical analysis scheme for filling simulation is accomplished by combining a finite element method with control volume technique to simulate the movement of flow front and a finite difference method to calculate the temperature distribution. The present study presents the modeling, numerical scheme and some numerical analysis results showing the effect of the yield stress and slip phenomena.

Mechanism of rock burst induced by fault slip in an island coal panel and hazard assessment using seismic tomography: a case study from Xuzhuang colliery, Xuzhou, China

  • Wang, Changbin;Cao, Anye;Zhu, Guangan;Jing, Guangcheng;Li, Jing;Chen, Tian
    • Geosciences Journal
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    • v.21 no.3
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    • pp.469-481
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    • 2017
  • Rock burst hazards induced by fault slip frequently occur in underground mining and threaten the safety of miners. In this paper, the structures of overlying strata, mechanism of fault slip, and rock burst pre-warning using seismic tomography were investigated in LW7192, a specific island longwall panel in Xuzhuang Colliery. The results show that an asymmetrical "T" structure of overlying strata is formed during LW7192 retreat, and the long hanging length of overlying key strata is maintained due to the short panel width. By analysing a modified fault sliding model, it is found that the time interval between two fault slips has a positive correlation with the energy released therein. The rock burst that occurred in LW7192 has the longest time interval between events compared with other high-energy tremors near the fault, and enormous elastic energies released by fault slip as a form of dynamic load. The superposition of dynamic loads and high stress concentration of the coal-rock mass contributes to the rock burst in LW7192. For forecasting rock burst hazards, seismic tomography was used and the results show that the velocity anomaly regions correspond well with the area of both strong tremors and the rock burst. Ultimately, large-diameter boreholes, directional hydraulic fracturing boreholes, and floor distressing boreholes were taken in the rock burst area, and the pressure relief is proved effective by seismic tomography assessment.

A low damage and ductile rocking timber wall with passive energy dissipation devices

  • Loo, Wei Yuen;Quenneville, Pierre;Chouw, Nawawi
    • Earthquakes and Structures
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    • v.9 no.1
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    • pp.127-143
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    • 2015
  • In conventional seismic design, structures are assumed to be fixed at the base. To reduce the impact of earthquake loading, while at the same time providing an economically feasible structure, minor damage is tolerated in the form of controlled plastic hinging at predefined locations in the structure. Uplift is traditionally not permitted because of concerns that it would lead to collapse. However, observations of damage to structures that have been through major earthquakes reveal that partial and temporary uplift of structures can be beneficial in many cases. Allowing a structure to move as a rigid body is in fact one way to limit activated seismic forces that could lead to severe inelastic deformations. To further reduce the induced seismic energy, slip-friction connectors could be installed to act both as hold-downs resisting overturning and as contributors to structural damping. This paper reviews recent research on the concept, with a focus on timber shear walls. A novel approach used to achieve the desired sliding threshold in the slip-friction connectors is described. The wall uplifts when this threshold is reached, thereby imparting ductility to the structure. To resist base shear an innovative shear key was developed. Recent research confirms that the proposed system of timber wall, shear key, and slip-friction connectors, are feasible as a ductile and low-damage structural solution. Additional numerical studies explore the interaction between vertical load and slip-friction connector strength, and how this influences both the energy dissipation and self-centring capabilities of the rocking structure.