RATIONALLY-BASED FATIGUE DESIGN OF TANKERS

The authors have developed a practical rationally-based fatigue design method which is sufficiently rapid and efficient to be part of preliminary structural design. The method consists of five basic steps: specifying a realistic wave environment, generating a hydrodynamic ship-wave interaction model, computing cyclic nominal stress due to waves and ship motions, using S-N data to predict fatigue life, and using structural optimization to re-size the scantlings such that the desired fatigue life is obtained. The paper describes the method and explains the similarities and the differences with other approaches. Example calculations involving a TAPS tanker are presented which validate the method, and which also demonstrate the importance of both local and overall structure response. The examples show that the heretofore unexplained fatigue cracking of midheight side longitudinals is caused by the local pulsating pressure due to waves and ship motions. This demonstrates clearly that fatigue analysis and design must include response to local panel pressure. Other fatigue analysis methods do not properly account for this effect.

  • Supplemental Notes:
    • Ship Structures Symposium '93; 16-17 Nov 1993; Arlington, Virginia, USA. Pprs. Publ by SNAME and the Ship Structure Committee, USA. Ppr E [19 p, 17 ref, 4 tab, 16 fig]
  • Authors:
    • Hughes, O
    • Franklin, P
  • Publication Date: 1993

Language

  • English

Subject/Index Terms

Filing Info

  • Accession Number: 00718315
  • Record Type: Publication
  • Source Agency: British Maritime Technology
  • Files: TRIS
  • Created Date: Mar 27 1996 12:00AM