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There are unconnected nodes in the mesh

  1. bei li

    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'

     

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    Replying to bei li

    1. Su Tian

      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?

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      Replying to Su Tian

    2. Su Tian

      The error says that there are unconnected nodes in the mesh. Could you send me the prevabs input file (.xml)?

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    3. Su Tian

      Sorry for mentioning that I also need the material database and airfoil file.

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    4. Su Tian

      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.

      trailing-edge.png

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      Replying to Su Tian

      1. bei li

        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?

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      2. bei li

        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?

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      3. Su Tian

        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.

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      4. bei li

        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?

        section.png

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    5. Su Tian

      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.

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      Replying to Su Tian

      1. bei li

        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?

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      2. bei li

        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?

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    6. bei li

      Is there any way to realize the visualization of the Tension Center、mass center and the principal bending axes of the Cross Section?

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      Replying to bei li

      1. Su Tian

        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.

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    7. bei li

      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?

      section.png

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      Replying to bei li

      1. Su Tian

        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.

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