The authors investigated the cause of failures frequently occurring in propeller shafts in way of the big end of cone part, using the results of a series of rotary bending fatigue tests with large specimens carried out by the Technical Research Laboratory of the Nippon Kaiji Kyokai. According to the results of investigation, the failure of shafts is assumed to occur in such manner that micro-cracks produce in these parts of the shaft at an early stage under low stress reversals, and the cracks so produced propagate due to the excessive stress in rough sea condition, causing the failure of the shaft. The results of a careful examination of the relationship between the shelly patterns on fractured surface and the roughness of sea conditions indicate that the propagation speed of cracks is in the order of 0.05-0.08 microns/cycle and the stress which shaft is subjected to is considered to be plus and minus 12-14 kg/, which implies that there is a large possibility of failure if microcracks have been produced. Accordingly, utmost caution should be paid to the watertightness and workmanship of press-fitting the propeller at the big end of cone part so as to prevent the initiation of micro-cracks, and further that in rough seas, ships should be handled with care so that the stress produced in the shaft may be as small as possible.

  • Corporate Authors:

    Society of Naval Architects of Japan

    23 Shiba-kotohiracho, Minato-ku
    Tokyo 135,   Japan 
  • Authors:
    • HARA, S
    • Yamashita, W
  • Publication Date: 1970

Media Info

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Filing Info

  • Accession Number: 00035202
  • Record Type: Publication
  • Source Agency: Society of Naval Architects of Japan
  • Files: TRIS
  • Created Date: Oct 27 1972 12:00AM