Offshore structures intended for use in the North Sea are expected to experience loading which could give rise to fatigue damage. As a consequence the tubular members and joints of steel structures are designed for a specific fatigue life whose magnitude depends on whether the member under consideration is a critical or redundant member. The method currently employed for this estimate of fatigue life assumes that no defects or flaws are present in the structure prior to service and in consequence makes allowance for both crack initiation and propagation. It would seem more appropriate to assume that small surface or embedded cracks are always present and that these will grow during service to form through-the-thickness cracks and eventually failure of the member, unless repair is undertaken. A calculation based on this assumption could be used to estimate the life of the structure or alternatively the inspection interval or time before repair is necessary. The procedure necessary for this calculation relies heavily on fracture mechanics, an approach based on the stresses existing near the tip of the crack, and the use of a suitable fatigue crack growth expression.

  • Corporate Authors:

    Society of Environmental Engineers

    68 a Wigmore Street
    London W1H 9DL,   England 
  • Authors:
    • Dover, W D
  • Publication Date: 1976-3

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00148552
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Files: TRIS
  • Created Date: Mar 15 1977 12:00AM