Flexcom 2025.1.2 |
 
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Flexcom 2025.1.2 |
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The following faults are present in Flexcom 2025.1.2. More detailed information on each fault is provided in the following sections.
No |
Issue |
Severity |
1 |
Hoop stress is incorrectly computed where the internal diameter of an element is zero |
Minor |
2 |
Slug display may not always function if a model contains several overlapping slugs |
Minor |
3 |
Variable time step selected by Flexcom lower than expected |
Minor |
4 |
LifeTime Mode 2 (cycle counting) not running for keyxm & keyxi files |
Minor |
5 |
LifeTime Mode 1 (fatigue analysis) presents the default stress histogram for a non-critical hotspot location |
Minor |
6 |
LifeTime Mode 1 (fatigue analysis) presents stress histograms at one angular location on the local cross-section only |
Minor |
7 |
LifeTime plot numbers not sequential in terms of formatting |
Minor |
8 |
Summary Postprocessing "Length on Seabed output" based on nodal proximity to seabed rather than actual contact modelling |
Minor |
9 |
Summary Postprocessing requests for aerodynamic variables (AeroDyn) requests must come before control variables (ServoDyn) |
Minor |
10 |
Model view doesn't work over remote desktop |
Major |
11 |
Wind Field Generator app generates excessively long file names which TurbSim cannot process |
Minor |
•Related Topics: Postprocessing
•Description: Hoop stress is incorrectly computed where the internal diameter of an element is zero. This is unlikely to occur in practice, unless you are modelling a solid bar for example.
•Workaround: You could specify a small, but non-zero value for internal diameter under *PROPERTIES. Or you could compute hoop stress manually using the internal and external pressure outputs which are readily available from Flexcom.
•Related Topics: Visualising Slug Flow
•Description: Slug display may be unreliable if a model contains several overlapping slugs. You may encounter the warning message "Problems occurred during slug display. Slugs will not be displayed after Time X", beyond which point no slugs are displayed in the structural animation. Note that the slugs are still accommodated correctly in the numerical model, so it is purely a display issue. You may use *PRINT->OUTPUT=SLUG FLOW to verify that each element has the correct internal contents.
•Workaround: Use *PRINT->OUTPUT=SLUG FLOW to verify that each element has the correct internal contents.
•Related Topics: Variable Time Stepping
•Description: The automatic time stepping algorithm fails to increase the solution time step in a restart analysis if the simulation time is lower than the end time of the preceding simulation. In this case, the program incorrectly believes that the current simulation is within an active ramp period and therefore prevents any time stepping increase, even if the solution is repeatedly achieving numerical convergence on the first iteration. This behaviour dates back to early versions of Flexcom where the start and end times of consecutive restart simulations had to correspond exactly. Nowadays all simulations tend to start from time t=0s, regardless of any preceding stages.
•Workaround: There are several possible workarounds.
1.Increase the start time of the restart analysis to be equal to the end time of the preceding stage.
2.Ignore the issue and wait for the simulation to complete normally.
3.Increase the minimum time step size, forcing the simulation to proceed more quickly.
4.Insert a token restart analysis into the chain, with a start and end time of 0s and 0.1s respectively. This effectively resets the end time of the preceding simulation to a very low value.
•Related Topics: LifeTime Cycle Counting (Mode 2)
•Description: LifeTime cycle counting does not function for keyword files which have in-build metric (keyxm) or imperial (keyxi) units. The LifeTime analysis terminates prematurely with a spurious error message, "The extension of this keyword file (.keyxm) must match that of the keyword file(s) that generated the seastate files (.keyx)". This occurs even if the Flexcom seastate simulations have the same keyword file extension as the LifeTime input file.
•Workaround: Rename all the input files with a .keyx file extension and re-run the simulations. Contact Wood if you require any assistance converting keyxm/keyxi files to keyx format.
•Related Topics: LifeTime Fatigue Analysis (Mode 1)
•Description: When you run a fatigue analysis, the main output file (*.out) presents you with a stress histogram for the hot spot with the lowest fatigue life (and the location on the cross-section at which this minimum occurs). But occasionally LifeTime can present the stress histogram at a hotspot which does not correspond to the critical location. This fault relates to histogram output only and does not affect the main fatigue computations.
•Workaround: Manually request a stress histogram at the critical location via *HISTOGRAM DATA.
•Related Topics: Stress Histograms
•Description: LifeTime allows you to request stress histograms at any location of interest, by specifying a hotspot and an angular location on the cross-section via an integer input (1 = 0°, 2 = 45°, 3 = 90° etc.). However it is not possible to request a histogram for more than one angular location at any given hotspot, as LifeTime incorrectly issues an error message regarding request duplication.
•Workaround: Run a series of separate fatigue analyses, requesting a stress histogram at a different location each time under *HISTOGRAM DATA.
•Related Topics: LifeTime Fatigue Analysis (Mode 1)
•Description: All plots generated by LifeTime are numbered consecutively but the number of digits is not sufficient. This causes a minor inconvenience in the sense that the plots do not appear in alphabetical order in the File View or Windows Explorer. For example, the plots are named FileName.S1.mplt, ..., FileName.S9.mplt, FileName.S10.mplt. They should be named FileName.S01.mplt, ..., FileName.S09.mplt, FileName.S10.mplt.
•Workaround: Rename the plot files manually if you would like them to appear in alphabetical order.
•Related Topics: Summary Postprocessing, *PARA SEABED
•Description: In the context of the length of seabed output, nodal contact is checked via the nodal's vertical position with respect to the seabed. If a node is within 0.001 metres (or feet, in the case of imperial units) of the seabed, then it is deemed to be in contact. A more correct procedure is to check the seabed contact flag which is written to the results database, as this is a direct representation of the situation in the finite solver.
•Workaround: The problem, if it is an issue of concern for you, may be minimised by using shorter elements in the touchdown zone.
•Related Topics: Summary Postprocessing, *PARA AERODYN, *PARA SERVODYN
•Description: Summary Postprocessing will produce erroneous results if the *PARA SERVODYN keyword appears before the *PARA AERODYN keyword. This issue is caused by a bug in the keyword reading subroutines which mixes up the postprocessing requests during keyword reading and storage.
•Workaround: Ensure to place *PARA AERODYN before *PARA SERVODYN in your keyword file.
•Related Topics: Model View
•Description: Flexcom's model view appears blank when the program is viewed over a Windows remote desktop connection. This issue has persisted for several years so we are delighted to say that it has been fully resolved in Flexcom 2025.1.3 and subsequent versions. When using Flexcom over remote desktop, please ensure to set the rendering option to software in the Flexcom Settings dialog.
•Workaround: Use an alternative tool such as VNC Viewer if you wish to view Flexcom models remotely and are yet to upgrade your Flexcom version.
•Related Topics: Wind Field Generator
•Description: The WFG app writes the file name and full file path to the Filename_BTS entry in the InflowWind input file. Unless the file path is quite short, InflowWind is unable to process the file name subsequently.
•Workaround: Use a standard text editor like NotePad++ to remove the file paths from all your InflowWind input files before running the Flexcom simulations.