• Title/Summary/Keyword: limiting sway method

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Limiting the sway on multi-storey un-braced steel frames bending on weak axis with partial strength connections

  • Tahir, Mahmood Md.;Ngian, Poi Shek
    • Structural Engineering and Mechanics
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    • v.38 no.6
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    • pp.825-847
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    • 2011
  • This paper investigates the design using wind-moment method for semi-rigid un-braced steel frames bending on weak axis. A limiting sway method has been proposed to reduce the frame sway. Allowance for steel section optimization between moment of inertia on minor axis column and major axis beam was used in conjunction with slope-deflection analysis to derive equations for optimum design in the proposed method. A series of un-braced steel frames comprised of two, four, and six bays ranging in height of two and four storey were studied on minor axis framing. The frames were designed for minimum gravity load in conjunction with maximum wind load and vice-versa. The accuracy of the design equation was found to be in good agreement with linear elastic computer analysis up to second order analysis. The study concluded that the adoption of wind-moment method and the proposed limiting sway method for semi-rigid steel frame bending on weak axis should be restricted to low-rise frames not more than four storey.

Command Shaping Control for Limiting the Transient Sway Angle of Crane Systems

  • Hong, Kyung-Tae;Huh, Chang-Do;Hong, Keum-Shik
    • International Journal of Control, Automation, and Systems
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    • v.1 no.1
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    • pp.43-53
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    • 2003
  • A modified command shaping control to reduce residual vibrations at a target position and to limit the sway angle of the payload during traveling for container crane systems is investigated. When the maneuvering time is minimized, a large transient amplitude and steady state oscillations may occur inherently. Since a large swing of the payload during the transfer is dangerous, the control objective is to transfer a payload to the desired place as quickly as possible while limiting the swing angle of the payload during the transfer. The conventional shapers have been enhanced by adding one more constraint to limit intermediate sway angles of the payload. The developed method is shown to be more effective than other conventional shapers for prevention of an excessive transient sway. Computer simulation results are provided.

EFFECTS OF SORET AND DUFOUR ON NATURAL CONVECTIVE FLUID FLOW PAST A VERTICAL PLATE EMBEDDED IN POROUS MEDIUM IN PRESENCE OF THERMAL RADIATION VIA FEM

  • RAJU, R. SRINIVASA
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.20 no.4
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    • pp.309-332
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    • 2016
  • Finite element method has been applied to solve the fundamental governing equations of natural convective, electrically conducting, incompressible fluid flow past an infinite vertical plate surrounded by porous medium in presence of thermal radiation, viscous dissipation, Soret and Dufour effects. In this research work, the results of coupled partial differential equations are found numerically by applying finite element technique. The sway of significant parameters such as Soret number, Dufour number, Grashof number for heat and mass transfer, Magnetic field parameter, Thermal radiation parameter, Permeability parameter on velocity, temperature and concentration evaluations in the boundary layer region are examined in detail and the results are shown in graphically. Furthermore, the effect of these parameters on local skin friction coefficient, local Nusselt number and Sherwood numbers is also investigated. A very good agreement is noticed between the present results and previous published works in some limiting cases.