Abstract
The fatigue life of offshore steel structures under stochastic loading is studied in the present investigation. Of special interest is the problem of fatigue damage accumulation and in this connection, a comparison between experimental results and results obtained using current codes and specifications.
Fatigue test series with various types of stochastic loading that are realistic in relation to offshore structures have been carried through. Four different load spectra with irregularity factors ranging from ∼~0.70 to 1.00 have been applied. The experimental investigation comprises both test series on full-scale tubular joints and test series on smaller welded test specimens. The materials that have been used until now have been ordinary offshore structural steels, with a yield stress of fy ∼ 360-410 MPa.
The test series that have been carried through show a significant difference between constant amplitude and variable amplitude fatigue test results. For the welded plate test specimens, approx. 150 fatigue tests have been carried out, and the values of the Miner sum that were obtained in the variable amplitude test series, generally vary in the range ∼ 0.40-0.85. For the full-scale tubular joints, the number of test results is at present too limited to draw final conclusions. However, the results obtained until now indicate a value of the Miner sum of M ∼ 0.6-0.8 for the variable amplitude tests.
Fatigue test series with various types of stochastic loading that are realistic in relation to offshore structures have been carried through. Four different load spectra with irregularity factors ranging from ∼~0.70 to 1.00 have been applied. The experimental investigation comprises both test series on full-scale tubular joints and test series on smaller welded test specimens. The materials that have been used until now have been ordinary offshore structural steels, with a yield stress of fy ∼ 360-410 MPa.
The test series that have been carried through show a significant difference between constant amplitude and variable amplitude fatigue test results. For the welded plate test specimens, approx. 150 fatigue tests have been carried out, and the values of the Miner sum that were obtained in the variable amplitude test series, generally vary in the range ∼ 0.40-0.85. For the full-scale tubular joints, the number of test results is at present too limited to draw final conclusions. However, the results obtained until now indicate a value of the Miner sum of M ∼ 0.6-0.8 for the variable amplitude tests.
| Original language | English |
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| Publisher | Danmarks Tekniske Højskole |
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| Number of pages | 109 |
| Publication status | Published - 1992 |
| Series | Afdelingen for Bærende Konstruktioner, ABK-SR |
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| Number | 299 |