Time Domain Fatigue Analysis |
 
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Time Domain Fatigue Analysis |
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Flexcom possesses an ancillary module, LifeTime, which is a time domain fatigue postprocessor and general cycle counting tool. LifeTime can operate in two ways - in the program terminology, LifeTime has two Modes of Operation, which are identified as Mode 1 and Mode 2.
Mode 1 is the more usual method of running the program, and is used to compute fatigue life estimates from the results of Flexcom simulations. The different methods used by the program to accomplish this task are detailed later in this section.
In the second mode of operation, LifeTime can be used as a general cycle counting tool. The input in this case is a random response time history or histories, typically the output from a Flexcom random sea analysis stored in Timetrace format. However you can use LifeTime to cycle count any time history data organised in a format which mimics the timetrace output format. The LifeTime Mode 2 output is simply histograms of response.
Further information on this topic is contained in the following sections:
•Fatigue Analysis (Mode1) describes the sequence of steps involved in performing a time domain fatigue analysis.
•Cycle Counting (Mode2) describes the sequence of steps involved in performing a general cycle counting analysis.
•Input Data describes various pertinent program inputs which merit further elaboration.
•Stress Histogram discusses the relevance of stress histograms and their associated parameters.
•Numerous keywords are contained in the $LIFETIME FATIGUE section, which corresponds to LifeTime Mode 1.
•Numerous keywords are contained in the $LIFETIME CYCLE section, which corresponds to LifeTime Mode 2.
If you would like to see an example of how these keywords are used in practice, refer to A01 - Deepwater Drilling Riser.