The Experts below are selected from a list of 219 Experts worldwide ranked by ideXlab platform

Zhang Qi Wang - One of the best experts on this subject based on the ideXlab platform.

  • Wind-Induced Response of UHV Guyed Single-Mast Transmission Tower-Line System
    Applied Mechanics and Materials, 2014
    Co-Authors: Wen Gang Yang, Bo Wen Zhu, Zhang Qi Wang
    Abstract:

    Ultra-high voltage Guyed Tower is typical structure of tall and slender, with the character of nonlinear and more sensitive to wind loads. Wind load is one of the most important control loads during design phase. A single-mast Guyed Tower recommended by a UHV DC transmission line was set as an example in this paper. The finite-element model of transmission Tower-line system was built, based on Davenport, fluctuating wind velocity time-history was simulated, the result of wind-induced response was analyzed. The result indicates that, as for displacements of the nodes on Guyed Tower, the mean values of wind-induced response are greater than the displacements under the static equivalent wind loads. As for axial forces of the leg members on Guyed Tower, the axial forces under the static equivalent wind loads are less than the max values of wind-induced response.

  • The Influence of Initial Guy Cable Prestress on Single-Mast Guyed Towers Mechanical Properties
    Applied Mechanics and Materials, 2013
    Co-Authors: Wen Gang Yang, Kai Zhang, Zhang Qi Wang
    Abstract:

    A single-mast Guyed Tower recommended by a UHV DC transmission line was set as an example. To study initial guy cable prestresss influence on Guyed Towers mechanical properties, the Guyed Tower under wind load was analyzed with finite element method considering geometry nonlinearity. Result shows: when initial guy cable prestress is less than critical guy cable prestress, with the growth of initial guy cable prestress, nodes displacement decreases, guy cables work stress and leg members axial force stay; when initial guy cable prestress is greater than critical guy cable prestress, with the growth of initial guy cable prestress, nodes displacement stays, guy cables work stress and leg members axial force proceed a linear increase.

Yang Wengan - One of the best experts on this subject based on the ideXlab platform.

  • Time History Analysis on Wind-induced Response of UHV Guyed Single-mast Transmission Tower-line System
    2015
    Co-Authors: Yang Wengan
    Abstract:

    The UHV Guyed Tower is typical structure of tall and slender, if it can be satisfy the wind resistance design became a hotspot around the engineers who engaged in transmission line engineering. The nonlinear finite element model of UHV Guyed single-mast transmission Tower-line system was built. The wind load time history about the transmission Tower-line system was simulated by the linear filtering method. Wind-induced response of the transmission Tower-line system was analyzed by Newmark method. Result shows: Under the condition of high wind, whose angle is 90 o, the mast's downwind rigid body rotation around bottom is the major factor caused downwind displacements of the mast's nodes. Guyed Tower produced downwind rigid body swing and bending vibration, and also produced torsional resonance around the axis of the mast. Because of Guyed Tower's torsional vibration, the mast which above the guy hang point produced torsional deformation, the diagonal member's axial force in that position is also large. Wind-induced response of displacements of nodes, the max values of leg members and diagonal members are all larger than corresponding values under static equivalent wind loads.

Wen Gang Yang - One of the best experts on this subject based on the ideXlab platform.

  • Wind-Induced Response of UHV Guyed Single-Mast Transmission Tower-Line System
    Applied Mechanics and Materials, 2014
    Co-Authors: Wen Gang Yang, Bo Wen Zhu, Zhang Qi Wang
    Abstract:

    Ultra-high voltage Guyed Tower is typical structure of tall and slender, with the character of nonlinear and more sensitive to wind loads. Wind load is one of the most important control loads during design phase. A single-mast Guyed Tower recommended by a UHV DC transmission line was set as an example in this paper. The finite-element model of transmission Tower-line system was built, based on Davenport, fluctuating wind velocity time-history was simulated, the result of wind-induced response was analyzed. The result indicates that, as for displacements of the nodes on Guyed Tower, the mean values of wind-induced response are greater than the displacements under the static equivalent wind loads. As for axial forces of the leg members on Guyed Tower, the axial forces under the static equivalent wind loads are less than the max values of wind-induced response.

  • The Influence of Initial Guy Cable Prestress on Single-Mast Guyed Towers Mechanical Properties
    Applied Mechanics and Materials, 2013
    Co-Authors: Wen Gang Yang, Kai Zhang, Zhang Qi Wang
    Abstract:

    A single-mast Guyed Tower recommended by a UHV DC transmission line was set as an example. To study initial guy cable prestresss influence on Guyed Towers mechanical properties, the Guyed Tower under wind load was analyzed with finite element method considering geometry nonlinearity. Result shows: when initial guy cable prestress is less than critical guy cable prestress, with the growth of initial guy cable prestress, nodes displacement decreases, guy cables work stress and leg members axial force stay; when initial guy cable prestress is greater than critical guy cable prestress, with the growth of initial guy cable prestress, nodes displacement stays, guy cables work stress and leg members axial force proceed a linear increase.

A.k. Jain - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of Offshore Guyed Tower Platforms to Wind and Wave Forces
    Journal of Energy Resources Technology-transactions of The Asme, 1998
    Co-Authors: R.s. Bisht, T. K. Datta, A.k. Jain
    Abstract:

    The fundamental frequency of Guyed Tower platforms is designed to be low, and, therefore, it is susceptible to low-frequency excitation caused by fluctuating components of the wind velocity. The dynamic response of a simplified model of the Lena Guyed Tower is obtained for the fluctuating component of the wind force and the wave force. Both wind velocity and water particle kinematics due to wave motion are modeled as stationary random processes and are simulated from their respective power spectral density functions. The response analysis is performed by an iterative frequency domain procedure which duly considers the nonlinearities produced due to the drag effect and the nonlinear guyline resistance. The responses are also obtained in the presence of current. A parametric study is conducted to evaluate the relative contribution to the responses made by the wind force. The parametric study also illustrates how the current modifies the overall dynamic response. It is shown that the wind force significantly influences the first mode displacement response of the Tower; the bending moment and shear force are not much affected by it. The current velocity tends to modify the peaks of the power spectral density function of the displacement response.

  • Wind and wave induced behaviour of offshore Guyed Tower platforms
    Ocean Engineering, 1998
    Co-Authors: R.s. Bisht, A.k. Jain
    Abstract:

    Abstract Offshore Guyed Tower platforms belong to the group of compliant offshore platforms which are most suited for deep water exploration. The basic feature of compliant offshore platforms is that they are designed to move with the waves, in at least some degrees-of-freedom. As far as excitation of wave frequencies is concerned, the system opposes wave forces by inertial effects. The offshore Guyed Tower derives its stability against lateral movement from its mooring system. In this study, the response of offshore Guyed Towers to random forces generated by wind and wave is investigated. The exposed portion of the Tower is subjected to the action of turbulent wind, while the submerged portion is acted upon by random wave forces. The analysis includes the nonlinearities due to the Morison equation of drag force, the variable submergence effect due to waves, the instantaneous position of the Tower and force excursion relation of the mooring lines. A parametric study is conducted to investigate the behaviour of the Tower under waves, and the combined effect of wind and wave forces.

  • Stochastic response of Guyed Tower under second-order wave force
    Sadhana, 1995
    Co-Authors: T. K. Datta, R.s. Bisht, A.k. Jain
    Abstract:

    Guyed Towers have low natural frequencies compared with generally encountered wave frequencies. They are therefore highly susceptible to low frequency second-order wave forces resulting from the nonlinear phenomenon in the integrated fluid pressure on the submerged structure. A simplified approach is presented here to obtain the second-order wave forces encountered in random sea state for offshore Guyed Towers using a simulation procedure. Nonlinear response of a Guyed Tower to second-order and first-order wave forces, and a combination of the two are obtained in time domain. The time histories of responses and the wave forces are analysed to investigate their stochastic characteristics.

  • Dynamic Response of Offshore Guyed Towers to Low Frequency Wind Induced Loads
    1995
    Co-Authors: R.s. Bisht, A.k. Jain
    Abstract:

    Offshore Guyed Tower platform belongs to the group of compliant offshore platforms which is most suited for deep water search for oil and gas. The basic feature of compliant offshore platform is that it is designed to move with the waves, in at least some of its degrees-of-freedom. In this study the response of offshore Guyed Tower to random forces generated by wind and wave is investigated. The exposed portion of the Tower is subjected to the action of turbulent wind, while the submerged portion is acted upon by random wave forces. The analysis includes the nonlinearities due to drag force, the instantaneous position of the Tower and force-excursion relation of the mooring lines. A parametric study is conducted to investigate the behavior of the Tower under wave and the combined effect of wind and wave forces.

  • Low frequency drift oscillation of offshore Guyed Towers
    1994
    Co-Authors: R.s. Bisht, A.k. Jain
    Abstract:

    The Guyed Towers being compliant offshore systems have very low natural frequencies and therefore, are susceptible to low frequency excitation. Since second order drift forces in random sea have very low frequency contents, they may induce significant responses in the Guyed Towers. The time history of the drift forces is generated by using a simulation technique which obtains time histories of the square of the slowly varying wave envelope and instantaneous frequency dependent drift coefficients. The latter is determined from the mean viscous drift force acting on the Tower for regular waves having different periods, combined with specified current velocity and mass transport velocity. The response of the Guyed Tower to random drift forces is determined in iterative frequency domain and the guylines are replaced by nonlinear springs whose force-displacement relationship is determined from a separate cable analysis.

Dimos Polyzois - One of the best experts on this subject based on the ideXlab platform.

  • Design recommendations and comparative study of FRP and steel Guyed Towers
    Engineering Science and Technology an International Journal, 2018
    Co-Authors: Sami Alshurafa, Dimos Polyzois
    Abstract:

    Abstract The aim of this paper is to explore the potential use of advanced composite materials as an alternative material to conventional steel to design and fabricate a lightweight fiber reinforced polymer (FRP) Guyed Towers. Both theoretical and experimental testing are involved. The paper offers recommendations for the design of composite Towers using various non-linear finite element models. It contains a comparative cost analysis between an 81 m composite and a steel Guyed Tower both designed to resist identical loading conditions. The paper results confirmed that FRP Tower creates more economically viable alternatives and sustainable solutions to steel Towers in the future.

  • An experimental and numerical study into the development of FRP Guyed Towers
    Composite Structures, 2018
    Co-Authors: Sami Alshurafa, Dimos Polyzois
    Abstract:

    Abstract A research project has been carried out at the University of Manitoba, Canada, to develop fibre-reinforced polymer (FRP) meteorological Guyed Towers. Both theoretical and experimental results are presented in this paper. The theoretical work involved the development of finite element models to analyze the structural behavior of an 81 m Tower. The experimental work involved the testing of an 8.6 m long segment, representing the bottom segment of the 81 m Guyed Tower used in the analysis, under static and dynamic loading. This segment was constructed from three cells bonded together with epoxy resin to form an equilateral triangle shape. Each cell was fabricated using four layers of glass fibre matting for a total thickness of 5 mm with a sequence of [90°/0°/0°/90°] impregnated in epoxy resin. An extensive material testing program was also carried out to define the material properties for finite element analysis. The numerical results are compared with the experimental results to confirm the validity of the finite element models.

  • Finite element method for the static and dynamic analysis of FRP Guyed Tower
    Journal of Computational Design and Engineering, 2018
    Co-Authors: Sami Alshurafa, Hanan Alhayek, Dimos Polyzois
    Abstract:

    Abstract A research study has been carried out to provide design guidelines for glass-fiber reinforced polymer (GFRP) Guyed Tower. Both material testing and theoretical analysis are involved. The Tower examined in this study has 81 m in height with a uniform equilateral triangle cross section having sides of 450 mm. The Tower supported by seven sets of guy wires oriented at 120°, each set consisting of three guy wires. The Tower was assumed to be supported at the base by means of a pinned connection to provide full moment release. The Tower was analyzed using the finite element ANSYS software and was designed to satisfy both the ultimate and the serviceability limit state requirements of the CSA-S37-01 Standard. The Guyed Tower was analyzed in static to evaluate the Tower strength failure using several advanced failure theories. Modal analysis and full dynamic analysis using CSA-37-01 Standard were extensively performed to evaluate the vibration performance and to obtain an accurate dynamic response of the full-scale Tower. The paper presents the results obtained from material testing and from a finite element, ANSYS models developed for the static and dynamic analysis of the multi-cells 81 m lightweight-Guyed Towers.

  • Parametric study on the strength and stiffness of FRP meteorological Guyed Towers
    Mechanics of Advanced Materials and Structures, 2018
    Co-Authors: Sami Alshurafa, Hanan Alhayek, Dimos Polyzois
    Abstract:

    ABSTRACTThe research was conducted to explore the use of advanced materials to design an 81 m FRP Guyed Tower. Theoretical and experimental works are involved. Several non-linear finite element mod...

  • Design recommendations and comparative study of FRP and steel Guyed Towers
    Elsevier, 2018
    Co-Authors: Sami Alshurafa, Dimos Polyzois
    Abstract:

    The aim of this paper is to explore the potential use of advanced composite materials as an alternative material to conventional steel to design and fabricate a lightweight fiber reinforced polymer (FRP) Guyed Towers. Both theoretical and experimental testing are involved. The paper offers recommendations for the design of composite Towers using various non-linear finite element models. It contains a comparative cost analysis between an 81 m composite and a steel Guyed Tower both designed to resist identical loading conditions. The paper results confirmed that FRP Tower creates more economically viable alternatives and sustainable solutions to steel Towers in the future. Keywords: FRP, Guyed, Tower, Composite, Steel, ANSY