Structural simulation effect on fatigue life prediction of fixed offshore platform
- Brown and Root, Inc., Houston, TX (United States). Marine Engineering Dept.
In general the most fatigue sensitive section of the typical fixed offshore platform is the first horizontal bracing plan below the water surface. If it can be demonstrated that the fatigue damage in this area is due to local wave action only, a simplified analysis procedure can be developed to screen the numerous existing platforms for the likelihood of fatigue damage. In this paper, fatigue damage calculated for member ends in a simplified structural model is compared to results from a full structural model. The simplified model is constructed to accurately capture the local wave action stresses but not to mimic the dynamic behavior and the frame action of the full structure. The spectral dynamic fatigue procedure for the fixed offshore platforms is adopted for analysis. Various intermediate steps are highlighted to provide improved insight into the effect of structural simulation on fatigue life prediction. It is shown that the global frame action and dynamic behavior of the structure are important aspects, and a simplified simulation of the structure which alters these characteristics can lead to erroneous results in the fatigue life predictions for the joints.
- OSTI ID:
- 89805
- Report Number(s):
- CONF-940113--; ISBN 0-7918-1184-0
- Country of Publication:
- United States
- Language:
- English
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