In a ship structure there are many deep girders serving as the main strength members. Under increasing loads local failures such as buckling, yielding, etc., may occur in these members, resulting in reduction of their stiffness. The changes of the relative stiffness of the members in the structure induce redistribution of the internal forces. Finally the structure shows its ultimate strength. There are powerful tools to analyse nonlinear behavior, such as the finite element method, the finite strip element method, etc. However, the ultimate strength analysis of large structures by these methods requires enormous computation time and under the present circumstances it is impossible to apply them directly. To overcome this difficulty, an analytical large size unit is proposed and idealization of the highly nonlinear behavior is developed in this paper. An "Idealized structural unit" is proposed as an element for the analysis. Conditions for nonlinear behavior and stiffness matrices of the element are derived for individual kinematic conditions, such as after buckling, at the ultimate strength or plastic strength, under compression, bending and/or shear. Based on this unit, a method of ultimate strength analysis, "Idealized Structural Unit Method", is proposed. The results of analysis by this method describe the detailed behavior of structures. A simple example structure coincides very well with experimental behavior observed in this study. The necessary computation time by this method is remarkably short. The nature of the new method promises validity and the realizable application to large size structures.

  • Supplemental Notes:
    • From the Selected Papers of the Journal of the Society of Naval Architects of Japan, Volume 13 (1975). Available from MRIS at $1.50 plus $0.10 a page.
  • Corporate Authors:

    Society of Naval Architects of Japan

    23 Shiba-kotohiracho, Minato-ku
    Tokyo 135,   Japan 
  • Authors:
    • Ueda, Y
    • Rashed, SMH
  • Publication Date: 1975

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  • Accession Number: 00308369
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 27 1980 12:00AM