FEASIBLE TIME DOMAIN JACKET FATIGUE ANALYSES
Said Fawad Mohammadi1; Nelson Prof. Dr.-Ing. Szilard Galgoul1; Uwe Prof. Dr.-Ing. Starossek2; Paulo Maurício Videiro3
1 Universidade Federal Fluminense; 2 Hamburg University of Technology; 3 Petróleo Brasileiro S.A.
Baixar PDF doi:10.20906/CPS/CILAMCE2015-0199
Resumo
While many fixed offshore platforms in Brazil date back to the 1980's, inspections have shown that they can safely remain in service for a longer period than originally forecast. These inspections are costly and, therefore, have been minimized based on computational methods developed to assess the risk associated with structural fatigue failure. Early deterministic fatigue analyses were inaccurate and have thus been replaced by spectral fatigue techniques, which are considered a feasible method to determine the fatigue life. In spite of their wide recognition, the accuracy of these analyses is still unsatisfactory since they provide only a qualitative indication of the remaining service life. The most accurate way of determining the remaining fatigue life is a time domain analysis that simulates an irregular water surface, which so far has been too computationally demanding to be considered feasible. This paper contributes to the literature in two important ways. First, it proposes a novel approach for time domain fatigue analysis that drastically reduces the computational burden, while maintaining a high degree of accuracy. Second, this paper shows the impact that the main parameters have on the results and thus provides practical guidance on carrying out fatigue analyses in the time domain.
Palavras-chave: Life Extension; Fixed Platforms; Time Domain Analysis; Fatigue Analysis