Storage Options |
 
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Storage Options |
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Database output is generally produced by Flexcom, but you have option to disable it completely, though this would be quite unusual in practice. If you are interested in database output, a range of options is provided to specify the frequency and level of data stored.
By default, Flexcom creates a default database based on the analysis type...
•Static and quasi-static analyses – database output produced at the final solution time only (equivalent to the End of Analysis option under the *DATABASE keyword)
•Dynamic analyses – database output produced at certain time steps only (equivalent to the Selected time steps option under the *DATABASE keyword). The Recording Interval is equal to the solution time step in a fixed time step analysis, and the maximum time step in a variable time step analysis. The Start Time is equal to the solution start time.
The standard level of output comprises the following:
(i)Nodal motions for all nodes in the model (including auxiliary nodes)
(ii)Axial forces and effective tensions for all elements
(iii)Shear forces for all elements
(iv)Bending moments and curvatures for all elements
(v)Torque moments for all elements
(vi)Reactions at all restrained nodes
You may also specify the frequency of database output. The options include All time steps (the default), which produces database output at all solution times, Selected time steps, which produces output at a recording interval you specify, and End of Analysis, which produces output at the final solution time only.
You may also customise the database, to control the contents of the motion and force database files that are produced by Flexcom. By reducing the number of parameters that are output to the database files, and/or the number of elements for which those parameters are output, and/or the number of data storage points per element, it is possible to substantially reduce the size of the database files produced. This can be particularly useful for large models and/or long simulation runtimes, especially if only a particular section of the model or certain parameters are of interest.
A further advantage of customisation is that you may request that runtime generated statistics of nodal motions and element restoring forces are included in the database files. If requested, Flexcom automatically calculates statistical parameters (minimum, maximum, mean and standard deviation) during dynamic analyses for nodal positions and certain element restoring forces (effective tensions, local-y and local-z-shear forces, torque moments, and local-y and local-z bending moments) while the analysis is running. These results are shown in the main analysis output file (jobname.out) at the end of the analysis. Additionally, these statistical parameters are written to the database files. This may be useful for analyses with long simulation runtimes where subsequently generating statistics using the database postprocessor can take a long time. If runtime-generated statistics have been included in the database files, and you subsequently request a plot of statistics using the database postprocessor, the postprocessor checks if the relevant data is included in the runtime statistics. If it is, the relevant data is simply read from the database files; if it is not, the database postprocessor must scan the database files to calculate the relevant statistical parameters. Including runtime-generated statistics in the database files can save a considerable amount of time during subsequent postprocessing, although this is at the expense of increased database file size.
•*DATABASE is used to specify the frequency of database output.
•*DATABASE CONTENT is used to customise the contents of the database output files.
If you would like to see an example of how these keywords are used in practice, refer to A01 - Deepwater Drilling Riser or B01 - Steel Catenary Riser.