The more accurate procedure for the dynamic analysis of flexible risers is time domain analysis. Time domain analyses takes into account all non linearities inherent to the system, such as geometry, soil-structure interaction etc. However, these analyses demand expensive computational effort and time. Others associated problems with time domain analyses are: the signal produced by simulation is not unique and the signal's length should be large enough to guarantee statistical parameters stability. An alternative method for this problem can be the use of frequency domain analysis instead of time domain analysis, since it is faster and requires much less effort. One of the main differences between the two methodologies is that the non linearities inherent to the system are linearized in the frequency domain and the effects of these modifications are not totally known, yet. Therefore, it was proposed to perform a comparative study between time and frequency domain analyses of flexible structures, analyzing the influence of not taking into account some non linearities and trying to find a range of applicability for frequency domain analyses.
Risers; time domain; frequency domain; dynamic analysis; offshore
