The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform

Denby Morrison - One of the best experts on this subject based on the ideXlab platform.

  • Quickwave: An Impulse Algorithm to Calculate Preliminary Design Shear and Moment Envelopes for Compliant Towers
    Journal of Offshore Mechanics and Arctic Engineering, 1995
    Co-Authors: Denby Morrison
    Abstract:

    A novel, simple method to calculate Compliant Tower (CT) level shear and moment envelopes for preliminary design has been developed, and verified by comparing with rigorous 3-D Tower analyses. The approach relies on a vast experience base to define important features influencing the dynamic response of CTs, and a new closed-form solution for the acceleration (needed to construct design envelopes) of the Tower caused by an impulsive-type wave load. The main benefits of the approach are: (1) the designer can iterate and quickly converge on a working preliminary design without resorting to time-consuming computer analyses; (2) the designer can quickly evaluate configurations for different water depths, pile arrangements, payload, and steel grade, reserve buoyancy, and well counts.

D G Morrison - One of the best experts on this subject based on the ideXlab platform.

  • Novel Dynamic Design Tools for Deepwater Towers that Achieved Breakthrough Results
    1996
    Co-Authors: D G Morrison
    Abstract:

    The novel design tools described in this paper included the "Designer Wave" and the "Quickwave" methods. The "Designer Wave" is a practical short portion of random wave simulation that captures enough of the structural response -- and shear and moment envelopes -- for design purposes. The "Quickwave" method achieves reasonably accurate design forces and member sizes without using time consuming random wave runs and full 3-D structural models. The Designer Wave is essential for the occasional calibration of the Quickwave results. Many design iterations are relatively easy with the Quickwave -- so much so that it was extensively used to derive a new deepwater Compliant Tower concept. The new Tower configuration resulted in breakthrough savings in weight and costs relative to existing solutions.

  • QUICKWAVE AND DESIGNER WAVE: UTILIZING APPROXIMATE METHODS FOR RIGOROUS PRELIMINARY DESIGN METHODS FOR Compliant TowerS
    1995
    Co-Authors: D G Morrison, J S Leonard
    Abstract:

    This paper describes the use of approximate (simple) and rigorous methods appropriate for the preliminary design of Compliant Towers. The novel design tools described include the "Designer Wave" and the "Quickwave". The design of deepwater bottom- founded Towers (300 to 1,000m) requires a good understanding of the nature of the design environment, the structural response, design force levels and practical member sizing. The "Designer Wave" is a practical short portion of random wave simulation, derived from rigorous analysis, that captures enough of the important features of structural response for design purposes. The "Quickwave" method achieves reasonably accurate design forces and member sizes without using time consuming random wave runs and full 3-D structural models. The Designer Wave is essential for the occasional calibration of the Quickwave results. Many design iterations are relatively easy with the Quickwave, so much so that it was extensively used to derive a new deepwater Compliant Tower concept.

  • the tensioned riser Compliant Tower
    Offshore Technology Conference, 1994
    Co-Authors: Sharon L. Smolinski, D G Morrison, D A Huete, Peter W Marshall
    Abstract:

    The Tensioned Riser Compliant Tower (TRCT) is a new concept in deepwater Compliant Towers which utilizes top-tensioned production risers instead of conventional laterally-supported drivepipes to provide individual well communication to the surface. A detailed design has been performed for 3000 foot water depth and compared with conventional designs to identify weight savings. Weight correlations have been developed for 15 and 30 well cases over a water depth range of 1350 to 3250 feet. Payload sensitivity has been examined, and detailed riser interference checks have been performed to determine minimum riser spacing.

John L. Tassoulas - One of the best experts on this subject based on the ideXlab platform.

  • Hydrostatic Effects in Tubular Member Design
    Journal of Offshore Mechanics and Arctic Engineering, 1994
    Co-Authors: Spyros A. Karamanos, John L. Tassoulas
    Abstract:

    This paper summarizes some important results concerning the analysis and design of tubular Compliant-Tower members. The tubes are subjected to a combination of structural loads and external pressure, which may cause buckling. The paper focuses on the effects of external pressure don the ultimate capacity. Analytical results are compared with experimental data and design equations. The comparison is aimed towards better understanding of pressurized tubular beam-column behavior.

Haym Benaroya - One of the best experts on this subject based on the ideXlab platform.

  • VIBRATION OF A Compliant Tower IN THREE-DIMENSIONS
    Journal of Sound and Vibration, 2002
    Co-Authors: Seon Han, Haym Benaroya
    Abstract:

    The three-dimensional motion of an offshore Compliant Tower using both rigid and flexible beam models is studied in this paper. The Tower is modelled as a beam supported by a torsional spring at the base with a point mass at the free end. The torsional spring constant is the same in all directions. When the beam is considered rigid, the two-degree-of-freedom model is employed. The two degrees constitute the two angular degrees of spherical co-ordinates, and the resulting equations are coupled and non-linear. When the beam is considered as elastic, three displacements are obtained as functions of the axial co-ordinate and time; again with coupled and non-linear equations of motion. The free and the forced responses due to deterministic loads are presented. The free responses of the rigid and elastic beams show rotating elliptical paths when viewed from above. The rate at which the path rotates depends on the initial conditions. When a harmonic transverse loading is applied in one direction, the displacement in that direction shows subharmonic resonance of order 1/2 and 1/3 while the displacement in the perpendicular direction is affected minimally. Next, in addition to the harmonic load in one direction, a transverse load is applied in the perpendicular direction. The transverse load varies exponentially with depth but is constant with time. It is found that the transverse load affects the transverse displacements in the perpendicular direction minimally.

  • Comparison of linear and nonlinear responses of a Compliant Tower to random wave forces
    Chaos Solitons & Fractals, 2002
    Co-Authors: Seon Han, Haym Benaroya
    Abstract:

    Abstract A vertical member of a Compliant offshore structure is modeled as a beam undergoing both bending and extension. The beam has a point mass and is subjected to a point axial load at the free end. The equations of motion for the axial and transverse displacements are nonlinear and coupled. A linear tension model is derived as a special case of the nonlinear coupled model with negligible axial displacement. The responses are obtained numerically for both models. A quarter of the International Ship and Offshore Structures Congress (ISSC) tension leg platform model is used as a numerical example. The free and forced responses obtained using the nonlinear coupled modeled are compared to those of the linear tension model.

  • NON-LINEAR COUPLED TRANSVERSE AND AXIAL VIBRATION OF A Compliant STRUCTURE, PART 1: FORMULATION AND FREE VIBRATION
    Journal of Sound and Vibration, 2000
    Co-Authors: Seon Han, Haym Benaroya
    Abstract:

    A Compliant Tower in the ocean environment is modelled as a beam undergoing coupled transverse and axial motion. The equations of motion are non-linear and coupled and are derived here. The beam is assumed to be supported by a linear-elastic torsional spring at one end and with a point mass at the other end. Such a model is representative of numerous applications. The equations of motion and boundary conditions are obtained using Hamilton's variational principle. It is assumed that strains are small but the rotation is moderate compared to the strain so that the equations of motion for the axial and transverse motion are non-linearly coupled. The free response in vacua and the free response in water are considered in particular. The fluid forces, the added mass and drag forces, are modelled using a semi-empirical Morison equation. The resulting non-linear coupled partial differential equations are solved numerically using the finite difference approach. In Part 2 of this work, various forced responses are studied.

Peter W Marshall - One of the best experts on this subject based on the ideXlab platform.

  • the tensioned riser Compliant Tower
    Offshore Technology Conference, 1994
    Co-Authors: Sharon L. Smolinski, D G Morrison, D A Huete, Peter W Marshall
    Abstract:

    The Tensioned Riser Compliant Tower (TRCT) is a new concept in deepwater Compliant Towers which utilizes top-tensioned production risers instead of conventional laterally-supported drivepipes to provide individual well communication to the surface. A detailed design has been performed for 3000 foot water depth and compared with conventional designs to identify weight savings. Weight correlations have been developed for 15 and 30 well cases over a water depth range of 1350 to 3250 feet. Payload sensitivity has been examined, and detailed riser interference checks have been performed to determine minimum riser spacing.