Application of the deterministic-spectral fatigue analysis method using platforms operating in non-linear wave loading conditions
- University College London (United Kingdom). Dept. of Mechanical Engineering
- British Gas PLC, Loughborough (United Kingdom). Gas Research Centre
It has previously been proposed that the so-called deterministic-spectral approach may have advantages over the deterministic approach for the fatigue analysis of shallow water fixed jacket platforms. In particular it is asserted that the deterministic-spectral approach can handle the random nature of the sea more adequately. The deterministic approach is currently the most widely used method for such platforms. In these earlier studies it was shown that the deterministic-spectral method can be applied successfully to certain types of shallow water jacket structures in the Rough Field area of the North Sea. Since this earlier study much more work has been done verifying the approach. In particular an alternative jacket platform in the Morecambe Bay area has been analyzed which exhibits, because of its shallower water depth, more severe non-linear tendencies. Results for this jacket are presented in the paper. Apparent discrepancies between the results obtained from the deterministic approach and those obtained from the deterministic-spectral approach have been notices. As a result of these discrepancies, a more detailed and sophisticated transient analysis (when compared to previous analyses) has been performed which utilizes different methods of decomposing the random sea surface elevation into its velocity, acceleration and associated force components. Results using this alternative method are presented. As a further aid to verifying and calibrating the technique a procedure for in-situ monitoring of the Morecambe Bay jacket is currently being developed and an outline of this monitoring work is presented.
- OSTI ID:
- 449719
- Report Number(s):
- CONF-9606279--; ISBN 0-7918-1490-4
- Country of Publication:
- United States
- Language:
- English
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