As a procedure of the safety design of offshore structures, a method of fatigue design is presented utilizing the dynamic response analysis of the structure and the stochastic data of wave, wind and tidal current. An actual design calculation was performed on a trussed leg of an offshore jack-up platform. The power spectra of wave and wind were first established using their significant values at the working area. The dynamic response of the platform was then investigated using a lumped mass model of three degrees of freedom system. From the frequency distribution function of the plastic strain variation obtained by the elastic stress concentration factors and the Neuber's formula, the fatigue life of the platform was estimated applying the Palmgren-Miner rule and the prescribed design fatigue curve of the material, in which the cumulative damage was evaluated taking into account all the loads of wave, wind and tidal current.

Media Info

  • Features: References;
  • Pagination: p. 873-888

Subject/Index Terms

Filing Info

  • Accession Number: 00138233
  • Record Type: Publication
  • Source Agency: Offshore Technology Conference
  • Report/Paper Numbers: V2, OTC 2607 Proceeding
  • Files: TRIS
  • Created Date: Aug 23 1976 12:00AM