PLASTIC DESIGN IN STEEL STRUCTURES (5TH REPORT) STUDIES ON PLASTIC DESIGN OF THE BIPOD-TYPE MASTS

In Japan the application of plastic design or limit design to a ship structure has been studied for a long time, and it has been recognized that the importance of maximum load carrying capacity (the ultimate load or limiting load of a structure determined by the criterion of structural usefulness of the structure) should be kept in mind in evaluating structural design. As can be easily understood, the first application of plastic design to ship structures was planned for independent structures of a ship's hull such as masts and derrick posts, because the effect of dynamic loading or fatigue strength for masts and derrick posts could be less important than other parts of ship. In fact, it was confirmed that fatigue effect due to repeating loads during cargo handling can be neglected for ordinary conditions. The characteristic feature of a ship's mast strength is the varying direction of load by swinging booms during cargo handling or the plastic strength analysis of a plane structure subjected to the spacial load. In this paper, the collapse by loads whose direction is at an arbitrary angle to the plane of the mast are dealt with by using two different yield conditions i.e., a spherical and a polyhedral yield surface. Experiments were carried out on twelve mast specimens and these results were compared with the theoretical calculation. The following were obtained conclusively: The analytical calculation based on the method described in this paper may easily be applied for actual mast design with sufficient accuracy.

  • Corporate Authors:

    Society of Naval Architects of Japan

    23 Shiba-kotohiracho, Minato-ku
    Tokyo 135,   Japan 
  • Authors:
    • Fujita, Y
    • Fujii, T
    • YOSHIDA, K
  • Publication Date: 1969

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Filing Info

  • Accession Number: 00035155
  • Record Type: Publication
  • Source Agency: Society of Naval Architects of Japan
  • Files: TRIS
  • Created Date: Oct 27 1973 12:00AM