Time Domain Analysis |
 
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Time Domain Analysis |
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This section discusses the time domain analysis capability in Flexcom. The presence of waves, whether regular or random, with or without current and/or vessel motions, requires you to specify a dynamic analysis. As Flexcom has traditionally been a time domain analysis tool, existing users may instinctively associate “‘dynamic analysis” with “time domain”.
•Time Variables describes the significance of time variables in a Flexcom dynamic analysis, and includes sub-sections discussing ‘Fixed Time Stepping’, ‘Variable Time Stepping’, ‘Choice of Time Step’, ‘Simulation Length’ and ‘Load Ramping’.
•Time Integration Algorithms describes the algorithms available in Flexcom for the discretisation of finite element equations of motion in time.
•Quasi-Static Analysis discusses the use of quasi-static analysis in circumstances where a converged static solution is difficult to achieve.
•Damping presents the range structural damping options available in Flexcom.
It is worth mentioning that the solution procedure in a time domain analysis may be specified as either Linear or Nonlinear. A linear analysis is one in which the structure stiffness, mass and damping matrices are assembled once only, at the simulation start time. The use of this option is valid where the structure displacements subsequently are such that it is reasonable not to reassemble these matrices. If this is not the case, a non-linear analysis is appropriate. The vast majority of time domain analyses are non-linear, and this option is selected by default.
•*ANALYSIS TYPE is used to specify the analysis type.
•*TIME is used to define time parameters for an analysis.
•*TIME STEPPING is used to select the time stepping algorithm and to define associated numerical damping coefficient.
If you would like to see an example of how these keywords are used in practice, refer to any of the standard Flexcom Examples.