EFFICIENT CALCULATION OF NATURAL FREQUENCIES OF CERTAIN MARINE STRUCTURES

The authors present, in this paper, a rapid method of analysis for determining the natural frequencies of pile supported platform type structures and their substructures. In as much as computer time requirements are less than for most other methods available for determining the natural frequencies, the procedure can be economically used in the design analysis of this type of structure and in many alternative designs. The method presented in this paper involves less approximations than most other methods. Its efficiency is attribute to the use of a theorem which can be used to determine the natural frequencies of undamped vibration of any linearly elastic structure for which a dynamic stiffness matrix can be calculated. This theorem enables advantage to be taken of identical portions, or substructures, which is particularly useful in the pile supported platform type structure. The basic theory is presented in detail and then is formulated for a platform supported on piles. As a case study, the authors analyzed the natural frequencies of the Immingham Oil Terminal. Comparison of the results with those of Sainsbury and King, as computed by conventional methods, disclosed a close correspondence of the computed natural frequencies. The advantage of this method over the methods used by Sainsbury and King was illustrated by the reduced computation time. The authors suggest a procedure wherein this analysis may be implemented to achieve a partially automated design.

  • Corporate Authors:

    Pergamon Press, Incorporated

    Maxwell House, Fairview Park
    Elmsford, NY  USA  10523
  • Authors:
    • Williams, F W
    • Wittrick, W H
  • Publication Date: 1973-10

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Filing Info

  • Accession Number: 00057133
  • Record Type: Publication
  • Source Agency: Texas A&M University, College Station
  • Files: TRIS
  • Created Date: Aug 16 1974 12:00AM