Winch Elements |
 
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Winch Elements |
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Winch elements are normal beam-column elements which have the unique property that their lengths can vary during an analysis. In a dynamic analysis, the variation in length may be defined in terms of a standard velocity profile or an arbitrary payout as a function of time. The operation in a static analysis is less complex, with an overall change in length being applied linearly from analysis start time to analysis end time.
The standard velocity profile is defined in terms of a maximum winch velocity and a winching time sequence. The time sequence consists of (i) a ramp-up time when winch velocity is increased from zero to the maximum value; (ii) a time during which the velocity remains at this maximum, and (iii) a ramp-down time when the velocity returns to zero. In the case of an arbitrary payout definition, a time history of extension/contraction is read directly from an external ASCII file.
Winch elements can be used, for example, in pipelaying applications, in simulating the transfer of an SCR from a lay vessel to a TLP or semi-sub.
•*WINCH is used to define winch elements.
If you would like to see an example of how this keyword is used in practice, refer to H04 - Pipe Laying.