Hi, everyone! I am a new user to VABS/iVABS. I’m trying to run the iVABS example below on Windows, but the analysis stops during the cross-section (cs) analysis step because a required .sg file cannot be found.
The example runs successfully and completes the cross-section analysis.
Actual behavior
It fails with:
FileNotFoundError: [Errno 2] No such file or directory: 'cs\\main_cs_set1.sg'
Log excerpt:
(ivabs) C:\Users\whhong\ivabs\examples\anl_blade_cs_rcas>ivabs analyze main.yml
raw args = ('C:\\Users\\whhong\\ivabs\\scripts\\msgd\\__main__.py', 'ivabs', 'analyze', 'main.yml')
list args = ('analyze', 'main.yml')
parsed args = Namespace(subparser_name='analyze', loglevelcmd='info', loglevelfile='info', logfile='eval.log', inputfile='main.yml', paramfile='', resultfile='')
variant = ivabs
[12:31:19] INFO reading main input main.yml... io.py:70
...
INFO [step: cs analysis] running cs analysis (h)... sg.py:149
cs: 0%| | 0/9 [00:00<?, ?it/s]
CRITICAL Traceback (most recent call last):
...
FileNotFoundError: [Errno 2] No such file or directory: 'cs\\main_cs_set1.sg'
...
Additional info / what I tried
I suspect this happens because prevabs did not generate the .sg file.
I tried running prevabs manually inside the cs folder:
prevabs -i main_cs_set1.xml -h -v
However, the command produces no output in the terminal, and it also does not generate the corresponding .sg file.
Question
Is cs/main_cs_set1.sg supposed to be included in the example package, or is it generated by a preprocessing step that I’m missing?
If it should be generated, could you please point me to the correct command/workflow to create it (and how to troubleshoot prevabs producing no output)?
@su.tian.22 Hi! I’m new to PreVABS and VABS, so I have a few questions—some of them may be quite basic. Recently, I’m using PreVABS v1.5 to generate .sg files and then running VABS v4.1 for the structural analysis. I noticed that the latest PreVABS release on GitHub is v1.6, and I’m wondering:
Does using different PreVABS versions (e.g., 1.5 vs 1.6) lead to differences in VABS results?
In addition, I’m having geometry-generation issues when running PreVABS on airfoils from the IEA 15MW wind turbine blade, mainly in two aspects:
For the FFA-W3-xxx series of sections, the trailing edge (TE) sometimes appears to be an open curve (not closed).
Does PreVABS provide any built-in handling for an unclosed TE (e.g., automatic TE closure, tolerance-based stitching, or point reordering)?
If not, what is the recommended preprocessing workflow (e.g., enforcing closure within a tolerance, adding a TE point, trimming/merging endpoints)?
For some airfoils, I see a self-intersection / crossing issue near the TE on the pressure side (PS): in the TE region, there are points with y > 0 on the PS, which causes PreVABS to fail and no results are produced.
How should this geometry problem be handled?
Is there a recommended method to repair the airfoil coordinates (e.g., re-sorting by arc length, splitting into suction/pressure sides and enforcing monotonicity, smoothing, removing duplicate points, or rebuilding the TE region)?
Any guidance, best practices, or example scripts/tools for cleaning these airfoil coordinate files would be greatly appreciated. Thanks!
PreVABS may not be suitable for fine control of a cross-section right now. If you do not consider doing parametric and automated cross-sectional building and analysis, you can try manually building the cross-section in a tool like Abaqus/CAE and generate the VABS input file. You can check out this example Build Cross-section in Abaqus and Export to VABS — SGIO. If you prefer other tools than Abaqus, please let us know. We can update sgio to handle the data format you need.