Dear All, there are two channels for you to follow our research.
1. We started a newsletter called Thoughts on Composites Modeling on LinkedIn. Please subscribe to it to get informed about our research and ideas we want to share with the community.
2. We moved our discussion forum to github at wenbinyugroup · Discussions · GitHub as it has more features which can serve you better.
Wenbin
bei li @ on
I encountered this error when running ivabs. This is Why? Thank you for your help！
There are unconnected nodes in the mesh
INFO | 2023-01-30 13:10:54 | execu.solve | reading results...
INFO | 2023-01-30 13:10:54 | dakota.writeOutput | writing output files...
INFO | 2023-01-30 13:10:54 | dakota.writeOutput | eval 1 failed
Traceback (most recent call last):
File "E:\ivabs\scripts\msgd\ivabs.py", line 184, in runDakotaEval
dda.analysis()
File "E:\ivabs\scripts\msgd\da\dakota.py", line 605, in analysis
design_analysis.run()
File "E:\ivabs\scripts\msgd\da\cs.py", line 60, in run
self.runH()
File "E:\ivabs\scripts\msgd\da\cs.py", line 134, in runH
logger=self.logger
File "E:\ivabs\scripts\msgpi\sg\execu.py", line 98, in solve
results = msi.readVABSOut(sg_in, analysis, scrnout)
File "E:\ivabs\scripts\msgpi\sg\io.py", line 615, in readVABSOut
return readVABSOutHomo(fn_in, scrnout)
File "E:\ivabs\scripts\msgpi\sg\io.py", line 273, in readVABSOutHomo
with open(fn, 'r') as fin:
FileNotFoundError: [Errno 2] No such file or directory: 'cs_1.sg.K'
Reply Report abuse
Su Tian @ on
This error usually means that the cross-sectional analysis failed. Either PreVABS failed to generate the VABS input or VABS failed to run that input file. Is the file 'cs_1.sg' generated?
Reply Report abuse
bei li @ on — Edited @ @ on
the file 'cs_1.sg' is generated
cs-1.zip
174 KBClick to download
Report abuse
Su Tian @ on
The error says that there are unconnected nodes in the mesh. Could you send me the prevabs input file (.xml)?
Reply Report abuse
bei li @ on
ok！Thank you！
cs-1.xml.zip
1 KBClick to download
Report abuse
Su Tian @ on
Sorry for mentioning that I also need the material database and airfoil file.
Reply Report abuse
bei li @ on
OK! Thank you again!
eval.1.zip
382 KBClick to download
Report abuse
Su Tian @ on
The issue is at the trailing edge. Please see the figure below. If you can adjust either point 'a' or 'b' so that let point 'b' be on the other side of the red line, then this should be fixed.
Reply Report abuse
bei li @ on
Because I am a beginner of this software, I would like to ask which file corresponds to point a and point b. I can basically understand your figure. I guess it is necessary to adjust the airfoil file, right?
Report abuse
bei li @ on
I want to know how you get this figure, because I have the same problem with other sections, but I can't determine which node in the airfoil file has the problem?
Report abuse
Su Tian @ on
Use the prevabs command line with the option '-v' to visualize it. Specifically, in the directory containing the cross-section xml file, run the following command:
prevabs -i cs_1.xml -h -vabs -v
Then a gmsh window should open and show the cross-section.
Report abuse
bei li @ on
Thank you for your answer. I tried. The previous section has been modified successfully. Now this is a new section. I try to find the problem. But when I see this picture, I still don't know where the problem is. Is there a problem with the red node connection? Or is the yellow part blank?
Report abuse
Su Tian @ on
Yes. Both points 'a' and 'b' should be in the airfoil file. My guess is that point 'a' is the first one and 'b' is the next in the point list.
Reply Report abuse
bei li @ on
OK! Thank you！
Report abuse
bei li @ on
I have another question. I want to ask why the Timoshenko beam stiffness matrix K66 is not equal to the Principal bending stiffness EI22 in the stiffness result file? This is because the calculation result of the stiffness matrix is based on the user-defined shaft, not the main bending crankshaft, right? So what should I do to make the stiffness value of Timoshenko beam stiffness matrix equal to Principal bending stiffness?
cs-1.sg.k.zip
2 KBClick to download
Report abuse
bei li @ on
I have calculated the stiffness of several sections, and several of them have the following errors:There are unconnected nodes in the mesh.（section13,16,18,19）
I have drawn the section diagram using the method you taught. I only know that the problems are near the trailing edge, but I do not know which nodes to modify, and what is the root cause of these problems? The thicker thickness at the trailing edge will lead to the overlap of the upper and lower sections of the paving layer, causing such a problem?However, there are also some sections（section14） at the trailing edge that overlap the upper and lower sections, but there is no above error. Why?
K.zip
3 KBClick to download
Report abuse
bei li @ on
Is there any way to realize the visualization of the Tension Center、mass center and the principal bending axes of the Cross Section?
Reply Report abuse
Su Tian @ on
Currently PreVABS cannot plot these. Maybe you can try to visualize the cross-section first and then manually add those objects in gmsh using its built-in tools.
Report abuse
bei li @ on
The previous section was successfully modified. Now this is a new section. I tried to find the problem. But when I saw this picture, I still didn't know what the problem was. From the figure, there is a problem with the connection of the nodes circled by the red line, and the part circled by the yellow line is blank, but how to modify it?
Cancel Report abuse
Su Tian @ on
My guess is that everything shown in this plot may not belong to a single "segment" in the input file. If they do, those geometries should be trimmed properly. If this does not fix it, you can send me the input files and I will test it.
Report abuse