SUBCRITICAL CRACK GROWTH AND SHIP STRUCTURAL DESIGN

A review is made of the factors which influence subcritical crack growth in conventional and high-strength, low-alloy steels of the type used in primary and secondary welded ship structures. The types of influencing factors considered are the metallurgical parameters, the fracture mechanics of the crack tip processes, the loading state, and the mechanisms of environmental attack. The fatigue process is separated into the crack initiation and (subcritical) crack propagation stages, and the relative influence of the above factors is discussed for each of these stages. Following this review, a basis for a design criterion is established for safe-life design of welded cargo ship structure. Two specific criteria are advanced: one which utilizes only the endurance strengths of the weldment types employed for constant-amplitude cyclic loading, and the other which sums the initiation and propagation lives each as governed by a spectral load distribution. These two criteria are compared, and existing gaps which need to be closed to elevate the confidence in the criteria are pointed out.

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  • Corporate Authors:

    Society of Naval Architects and Marine Engineers

    601 Pavonia Avenue
    Jersey City, NJ  United States  07306-2907
  • Authors:
    • Francis, P H
    • Lankford Jr, J
    • Lyle Jr, F F
  • Publication Date: 1976-4

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Filing Info

  • Accession Number: 00138344
  • Record Type: Publication
  • Source Agency: Society of Naval Architects and Marine Engineers
  • Files: TRIS
  • Created Date: Aug 11 1976 12:00AM