The large ships recently built in Japan are generally of the type with the entire superstructure aft, and for these vessels special attention should be paid to vibration especially to the fore-and-aft vibration of superstructures. The authors have carried out some experimental and theoretical investigation on these phenomena, and the following results have been obtained. (1) In full scale measurements, there were several peak groups recognized in the vicinities of 400-600 cycles per min and 800-1,000 cycles per min, of these the lowest have possibility of resonating with the so-called blade frequencies. (2) Measured mode curves had shown interesting characteristics. (3) Some qualitative investigations have been made on these experimental data, and it becomes clear that the coupled motion of the main hull, the elastic support at the base deck of superstructure and the dodger have a great deal of influence upon the vibratory characteristics of superstructure. (4) A method of predicting the lowest natural frequency of superstructure by the use of electronic computer has been obtained.

  • Corporate Authors:

    Society of Naval Architects of Japan

    23 Shiba-kotohiracho, Minato-ku
    Tokyo 135,   Japan 
  • Authors:
    • Hirowatari, T
  • Publication Date: 1969

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Filing Info

  • Accession Number: 00035159
  • Record Type: Publication
  • Source Agency: Society of Naval Architects of Japan
  • Files: TRIS
  • Created Date: Oct 27 1972 12:00AM