Riser long-term fatigue performance is an important design consideration. Although extensive application
of irregular sea analysis in time domain with the rainflow counting technique for post-processing is regarded
as the most accurate of the approaches for fatigue analysis, it does suffer from some limitations, such as the computational
effort. For this reason, two computationally efficient approaches are employed to perform the fatigue
analysis of a deepwater top-tensioned riser, based on the Longuet-Higgins distribution and time domain scaling
respectively. With Longuet-Higgins distribution irregular wave sea states are expanded into their individual wave
bins. These regular wave simulations are of short duration and consequently run quickly. Using the time domain
scaling technique, the number of irregular wave runs can be performed for a comparatively small number of load
cases and hence reduces the calculation time. The results showed a reasonable accuracy and significant efficiency
for both approaches, compared with those from the equivalent rainflow analysis. With much less computational
effort and disk storage requirement, the approaches outlined in this paper can therefore be used for the fatigue
assessment of deepwater risers in industry practice.
DONG Lei-lei* (董磊磊), ZHANG Qi (张 崎), HUANG Yi (黄 一), LIU Gang (刘 刚)
. Computationally Efficient Approaches to Fatigue Analysis of Deepwater Risers[J]. Journal of Shanghai Jiaotong University(Science), 2013
, 18(4)
: 493
-499
.
DOI: 10.1007/s12204-013-1425-y
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