FEM BUG HELP?

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xsuper9988
Posts: 223
Joined: Sat Oct 24, 2020 4:20 am

FEM BUG HELP?

Post by xsuper9988 »

FEM BUG HELP?

Operation Video:
https://youtu.be/uZLFa6ImH28

Operation FILE:
https://drive.google.com/file/d/11PRSJq ... sp=sharing

I can't get a normal shape by Gmsh mesher
And i can't get a normal fixed geometric entity
Is these a bugs???

My Ver:
FreeCAD-0.19.2.7b5e18a-WIN-x64-portable1
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Kunda1
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Re: FEM BUG HELP?

Post by Kunda1 »

Moved to FEM subforum, please always paste you full About info.
Also it's recommended with FEM to use the latest Development builds to get the most up to code changes (grab it from https://github.com/FreeCAD/FreeCAD-Bund ... kly-builds )
Alone you go faster. Together we go farther
Please mark thread [Solved]
Want to contribute back to FC? Checkout:
'good first issues' | Open TODOs and FIXMEs | How to Help FreeCAD | How to report Bugs
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UR_
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Re: FEM BUG HELP?

Post by UR_ »

Looks like a duplicate from this: ;)
https://forum.freecadweb.org/viewtopic.php?f=3&t=58671

Screenshot 003.png
Screenshot 003.png (18.64 KiB) Viewed 2571 times
Screenshot 002.png
Screenshot 002.png (318.5 KiB) Viewed 2571 times
If you aren't looking for a contact analysis, you need of course a single solid (Fusion)
to obtain one mesh instead of multiple even incoherent meshes.


file:
_FEM_noBUG_TEST-ur.FCStd
(86.51 KiB) Downloaded 71 times

version:
OS: Windows 10 (10.0)
Word size of FreeCAD: 64-bit
Version: 0.20.25024 (Git)
Build type: Release
Branch: master
Hash: 1fb45a0c5ee88ddd31c1e17b2b3efc83fc9106f6
Python version: 3.9.4
Qt version: 5.12.9
Coin version: 4.0.0
OCC version: 7.5.2
Locale: German/Germany (de_DE)
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xsuper9988
Posts: 223
Joined: Sat Oct 24, 2020 4:20 am

Re: FEM BUG HELP?

Post by xsuper9988 »

Sorry it has many errors
I dont know how to do?

Operation Videos:
https://www.youtube.com/watch?v=djW302s ... xsuper9988
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UR_
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Posts: 1355
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Re: FEM BUG HELP?

Post by UR_ »

xsuper9988 wrote: ↑Sun Jun 06, 2021 4:54 amI dont know how to do?

In my previous answer, I posted a link pointing to a similar analysis.

Following this, you should be able to read: Tetrahedrons should have a maximum aspect ratio of 2.

In your vid one can see:

Screenshot 001.png
Screenshot 001.png (285.79 KiB) Viewed 2509 times
That's too bad! :(

Please have a detailed look into Gmsh properties from above posted FCStd file.

Watching your vid, I can't see, if above mentioned Refinement and Defeaturing was done. ;)
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xsuper9988
Posts: 223
Joined: Sat Oct 24, 2020 4:20 am

Re: FEM BUG HELP?

Post by xsuper9988 »

I chang 10mm，10mm
It still fail

My video:
https://youtu.be/G_VMvXfBtiE


Code: Select all

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 
FEM MESH BY GMSH --- errors
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 
0.0: We are going to start ...
0.0: Start Gmsh ...
17.9: Gmsh had warnings ...
17.9: Warning : 1 ill-shaped tets are still in the mesh Warning : ------------------------------ Warning : Mesh generation error summary Warning : 1 warning Warning : 0 errors Warning : Check the full log for details Warning : ------------------------------ 
17.9: Gmsh done!
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

Code: Select all

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 
mechanical analysis --- errors
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 
0.0: Check dependencies...
18.3: Write completed.
0.0: CalculiX binary: F:/_3D_WORK_/FreeCAD/bin/ccx.exe
0.0: CalculiX input file: C:\Users\XSUPER~1\AppData\Local\Temp\fcfem_vfd88pj4\FEMMeshGmsh.inp
0.0: Run CalculiX...
0.0: Starting CalculiX...
0.0: CalculiX is running...
13.8: CalculiX stopped.
13.8: ************************************************************ 
CalculiX Version 2.17, Copyright(C) 1998-2020 Guido Dhondt 
CalculiX comes with ABSOLUTELY NO WARRANTY. This is free 
software, and you are welcome to redistribute it under 
certain conditions, see gpl.htm 
************************************************************ 
You are using an executable made on Thu Jul 23 21:43:50 CEST 2020 
The numbers below are estimated upper bounds 
number of: 
nodes: 150326 
elements: 128024 
one-dimensional elements: 0 
two-dimensional elements: 0 
integration points per element: 4 
degrees of freedom per node: 3 
layers per element: 1 
distributed facial loads: 0 
distributed volumetric loads: 0 
concentrated loads: 28330 
single point constraints: 19218 
multiple point constraints: 1 
terms in all multiple point constraints: 1 
tie constraints: 0 
dependent nodes tied by cyclic constraints: 0 
dependent nodes in pre-tension constraints: 0 
sets: 5 
terms in all sets: 539168 
materials: 1 
constants per material and temperature: 2 
temperature points per material: 1 
plastic data points per material: 0 
orientations: 0 
amplitudes: 2 
data points in all amplitudes: 2 
print requests: 1 
transformations: 0 
property cards: 0 
STEP 1 
Static analysis was selected 
Decascading the MPC's 
Determining the structure of the matrix: 
number of equations 
431760 
number of nonzero lower triangular matrix elements 
14688930 
Using up to 1 cpu(s) for the stress calculation. 
Using up to 1 cpu(s) for the symmetric stiffness/mass contributions. 
*ERROR in e_c3d: nonpositive jacobian 
determinant in element 86013 
*ERROR in e_c3d: nonpositive jacobian 
determinant in element 86013
13.8: CalculiX execute error: 
13.8: Loading result sets...
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 





= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 
Report View --- Errors
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = 
0.0: We are going to start ...
0.0: Start Gmsh ...
17.9: Gmsh had warnings ...
17.9: Warning : 1 ill-shaped tets are still in the mesh Warning : ------------------------------ Warning : Mesh generation error summary Warning : 1 warning Warning : 0 errors Warning : Check the full log for details Warning : ------------------------------ 
17.9: Gmsh done!



0.0: Check dependencies...
18.3: Write completed.
0.0: CalculiX binary: F:/_3D_WORK_/FreeCAD/bin/ccx.exe
0.0: CalculiX input file: C:\Users\XSUPER~1\AppData\Local\Temp\fcfem_vfd88pj4\FEMMeshGmsh.inp
0.0: Run CalculiX...
0.0: Starting CalculiX...
0.0: CalculiX is running...
13.8: CalculiX stopped.
13.8: ************************************************************ 
CalculiX Version 2.17, Copyright(C) 1998-2020 Guido Dhondt 
CalculiX comes with ABSOLUTELY NO WARRANTY. This is free 
software, and you are welcome to redistribute it under 
certain conditions, see gpl.htm 
************************************************************ 
You are using an executable made on Thu Jul 23 21:43:50 CEST 2020 
The numbers below are estimated upper bounds 
number of: 
nodes: 150326 
elements: 128024 
one-dimensional elements: 0 
two-dimensional elements: 0 
integration points per element: 4 
degrees of freedom per node: 3 
layers per element: 1 
distributed facial loads: 0 
distributed volumetric loads: 0 
concentrated loads: 28330 
single point constraints: 19218 
multiple point constraints: 1 
terms in all multiple point constraints: 1 
tie constraints: 0 
dependent nodes tied by cyclic constraints: 0 
dependent nodes in pre-tension constraints: 0 
sets: 5 
terms in all sets: 539168 
materials: 1 
constants per material and temperature: 2 
temperature points per material: 1 
plastic data points per material: 0 
orientations: 0 
amplitudes: 2 
data points in all amplitudes: 2 
print requests: 1 
transformations: 0 
property cards: 0 
STEP 1 
Static analysis was selected 
Decascading the MPC's 
Determining the structure of the matrix: 
number of equations 
431760 
number of nonzero lower triangular matrix elements 
14688930 
Using up to 1 cpu(s) for the stress calculation. 
Using up to 1 cpu(s) for the symmetric stiffness/mass contributions. 
*ERROR in e_c3d: nonpositive jacobian 
determinant in element 86013 
*ERROR in e_c3d: nonpositive jacobian 
determinant in element 86013
13.8: CalculiX execute error: 
13.8: Loading result sets...

16:06:38  
16:06:38  Error on reading card data. The card data will be empty for card:
F:/_3D_WORK_/FreeCAD/data/Mod\Material\StandardMaterial\Graphite.FCMat
16:06:38  choose_material in FEM material task panel:
    F:/_3D_WORK_/FreeCAD/data/Mod\Material\StandardMaterial\Graphite.FCMat
16:06:38  For some reason all material data is empty!
16:06:38  Density not found in material data of: Empty
16:06:38  YoungsModulus not found in material data of: Empty
16:06:38  PoissonRatio not found in material data of: Empty
16:06:38  ThermalConductivity not found in material data of: Empty
16:06:38  ThermalExpansionCoefficient not found in material data of: Empty
16:06:38  SpecificHeat not found in material data of: Empty
16:06:38  
16:06:41  choose_material in FEM material task panel:
    F:/_3D_WORK_/FreeCAD/data/Mod\Material\StandardMaterial\Steel-1C45.FCMat
16:06:41  ThermalConductivity not found in material data of: 1C45
16:06:41  SpecificHeat not found in material data of: 1C45
16:06:41  
16:06:43  Zero ThermalConductivity value. This parameter is not saved in the material data.
16:06:43  Zero SpecificHeat value. This parameter is not saved in the material data.
16:06:47  Active analysis found: Analysis
16:07:15  Active analysis found: Analysis
16:07:15    ElementDimension: 3
16:07:15    No Group meshing for analysis.
16:07:15    C:\Users\XSUPER~1\AppData\Local\Temp\fcfem_enuie5z9\Fusion_Geometry.brep
16:07:15    C:\Users\XSUPER~1\AppData\Local\Temp\fcfem_enuie5z9\Fusion_Mesh.unv
16:07:15    C:\Users\XSUPER~1\AppData\Local\Temp\fcfem_enuie5z9\shape2mesh.geo
16:07:15    F:/_3D_WORK_/FreeCAD/bin/gmsh.exe
16:07:15    New mesh was added to the mesh object.
16:07:15  Gmsh had warnings ...
16:07:15  Warning : 1 ill-shaped tets are still in the mesh
Warning : ------------------------------
Warning : Mesh generation error summary
Warning :     1 warning
Warning :     0 errors
Warning : Check the full log for details
Warning : ------------------------------

16:10:42  References: empty in MaterialSolid, MaterialSolid
16:10:42  References: Face in ConstraintFixed, ConstraintFixed
16:10:42  References: Face in ConstraintForce, ConstraintForce
16:10:42  Check prerequisites.
16:10:42  Check prerequisites.
16:10:42  References: empty in MaterialSolid, MaterialSolid
16:10:42  Start writing CalculiX input file
16:10:42  Write ccx input file to: C:\Users\XSUPER~1\AppData\Local\Temp\fcfem_vfd88pj4\FEMMeshGmsh.inp
16:10:42  ConstraintFixed:
16:10:42      Type: Fem::ConstraintFixed, Name: ConstraintFixed
16:10:42      ReferenceShape ... Type: Face, Object name: Fusion, Object label: Fusion, Element name: Face26
16:10:42      ReferenceShape ... Type: Face, Object name: Fusion, Object label: Fusion, Element name: Face30
16:10:42  ConstraintForce:
16:10:42      Type: Fem::ConstraintForce, Name: ConstraintForce
16:10:42      ReferenceShape ... Type: Face, Object name: Fusion, Object label: Fusion, Element name: Face1
16:10:42  Writing time CalculiX input file: 18.27 seconds 

16:10:51  run CalculiX at: F:/_3D_WORK_/FreeCAD/bin/ccx.exe with: C:\Users\XSUPER~1\AppData\Local\Temp\fcfem_vfd88pj4\FEMMeshGmsh.inp
16:11:10  

CalculiX returned an error due to nonpositive jacobian determinant in at least one element
Use the run button on selected solver to get a better error output.
16:11:10  Error() 
16:11:10  We will load the ccx frd and dat result file.
16:11:10  Read ccx results from frd file: C:\Users\XSUPER~1\AppData\Local\Temp\fcfem_vfd88pj4\FEMMeshGmsh.frd
16:11:10  Nodes, but no results found in frd file. It means there only is a mesh but no results in frd file. Usually this happens for: 
- analysis type 'NOANALYSIS'
- if CalculiX returned no results (happens on nonpositive jacobian determinant in at least one element)
- just no frd results where requestet in input file (neither 'node file' nor 'el file' in output section')
16:11:10  Read ccx results from dat file: C:\Users\XSUPER~1\AppData\Local\Temp\fcfem_vfd88pj4\FEMMeshGmsh.dat
16:15:20  CalxuliX ccx tools solver!
16:15:20  References: empty in MaterialSolid, MaterialSolid
16:15:20  References: Face in ConstraintFixed, ConstraintFixed
16:15:20  References: Face in ConstraintForce, ConstraintForce
16:15:20  Check prerequisites.
16:15:20  Check prerequisites.
16:15:20  References: empty in MaterialSolid, MaterialSolid
16:15:20  Start writing CalculiX input file
16:15:20  Write ccx input file to: C:\Users\XSUPER~1\AppData\Local\Temp\fcfem_ktrrqqj1\FEMMeshGmsh.inp
16:15:20  ConstraintFixed:
16:15:20      Type: Fem::ConstraintFixed, Name: ConstraintFixed
16:15:20      ReferenceShape ... Type: Face, Object name: Fusion, Object label: Fusion, Element name: Face26
16:15:20      ReferenceShape ... Type: Face, Object name: Fusion, Object label: Fusion, Element name: Face30
16:15:20  ConstraintForce:
16:15:20      Type: Fem::ConstraintForce, Name: ConstraintForce
16:15:20      ReferenceShape ... Type: Face, Object name: Fusion, Object label: Fusion, Element name: Face1
16:15:20  Writing time CalculiX input file: 18.5 seconds 

16:15:20  Writing CalculiX input file completed.
16:15:20  Run CalculiX ...
16:15:20  CalculiX failed with exit code 201
16:15:20  --------start of stderr-------
16:15:20  --------end of stderr---------
16:15:20  --------start of stdout-------
16:15:20  
************************************************************

CalculiX Version 2.17, Copyright(C) 1998-2020 Guido Dhondt
CalculiX comes with ABSOLUTELY NO WARRANTY. This is free
software, and you are welcome to redistribute it under
certain conditions, see gpl.htm

************************************************************

You are using an executable made on Thu Jul 23 21:43:50 CEST 2020

  The numbers below are estimated upper bounds

  number of:

   nodes:       150326
   elements:       128024
   one-dimensional elements:            0
   two-dimensional elements:            0
   integration points per element:            4
   degrees of freedom per node:            3
   layers per element:            1

   distributed facial loads:            0
   distributed volumetric loads:            0
   concentrated loads:        28330
   single point constraints:        19218
   multiple point constraints:            1
   terms in all multiple point constraints:            1
   tie constraints:            0
   dependent nodes tied by cyclic constraints:            0
   dependent nodes in pre-tension constraints:            0

   sets:            5
   terms in all sets:       539168

   materials:            1
   constants per material and temperature:            2
   temperature points per material:            1
   plastic data points per material:            0

   orientations:            0
   amplitudes:            2
   data points in all amplitudes:            2
   print requests:            1
   transformations:            0
   property cards:            0


 STEP            1

 Static analysis was selected

 Decascading the MPC's

 Determining the structure of the matrix:
 number of equations
 431760
 number of nonzero lower triangular matrix elements
 14688930

 Using up to 8 cpu(s) for the stress calculation.

 Using up to 8 cpu(s) for the symmetric stiffness/mass contributions.

 *ERROR in e_c3d: nonpositive jacobian
        determinant in element       86013

 *ERROR in e_c3d: nonpositive jacobian
        determinant in element       86013

16:15:20  
--------end of stdout---------
16:15:20  --------start problems---------
16:15:20  

CalculiX returned an error due to nonpositive jacobian elements.
16:15:20  nonpositive_jacobian_elements = [86013]
16:15:20  nonpositive_jacobian_elenodes = [2406, 4264, 44927, 46689, 78564, 79441, 110348, 110348, 112004, 113068]
16:15:20  
16:15:20  
Following some commands to copy. They highlight the nonpositive jacobians or to reset the highlighted nodes:
16:15:20  Gui.ActiveDocument.FEMMeshGmsh.HighlightedNodes = nonpositive_jacobian_elenodes
16:15:20  Gui.ActiveDocument.FEMMeshGmsh.HighlightedNodes = []

16:15:20  
--------end problems---------
16:15:20  CalculiX finished with error 201.

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
EDITED by Bernd, please use code tag for posting such logs
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UR_
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Posts: 1355
Joined: Tue Jan 03, 2017 8:42 pm

Re: FEM BUG HELP?

Post by UR_ »

Because diagnosis based on your fuzzy vid is a little bit vague, it would be nice if you can provide:

a) a FCStd file (with cleared mesh because of file size -> right click mesh object in tree view)
b) version numbers of FreeCAD, Gmsh and ccx
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User avatar
xsuper9988
Posts: 223
Joined: Sat Oct 24, 2020 4:20 am

Re: FEM BUG HELP?

Post by xsuper9988 »

UR_ wrote: ↑Sun Jun 06, 2021 4:23 pm Because diagnosis based on your fuzzy vid is a little bit vague, it would be nice if you can provide:

a) a FCStd file (with cleared mesh because of file size -> right click mesh object in tree view)
b) version numbers of FreeCAD, Gmsh and ccx
My Ver:
FreeCAD-0.19.2.7b5e18a-WIN-x64-portable1
24291(git)

My File:
https://drive.google.com/file/d/1opV2au ... sp=sharing

But i dont know where to find "Gmsh and ccx" File
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bernd
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Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland
Contact:
Contact bernd

Re: FEM BUG HELP?

Post by bernd »

xsuper9988 wrote: ↑Mon Jun 07, 2021 3:37 am
UR_ wrote: ↑Sun Jun 06, 2021 4:23 pm Because diagnosis based on your fuzzy vid is a little bit vague, it would be nice if you can provide:

a) a FCStd file (with cleared mesh because of file size -> right click mesh object in tree view)
My File:
https://drive.google.com/file/d/1opV2au ... sp=sharing

If you clear (not delete) your mesh the file is 49 kilo byte and could be posted here without any problem ...


_FEM_BUG_TEST2_mesch_cleared.FCStd
(48.18 KiB) Downloaded 65 times
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UR_
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Posts: 1355
Joined: Tue Jan 03, 2017 8:42 pm

Re: FEM BUG HELP?

Post by UR_ »

Unfortunately you ignored some advise :shock:

- Refinement not done
- Defeaturing not done
Screenshot 002.png
Screenshot 002.png (3.88 KiB) Viewed 2303 times
Screenshot 003.png
Screenshot 003.png (9.44 KiB) Viewed 2305 times

if you choose 2nd order elements and there are high curvature geometries (fillets),
you should set Second Order Linear to True
Screenshot 004.png
Screenshot 004.png (5.46 KiB) Viewed 2305 times
Screenshot 001.png
Screenshot 001.png (323.56 KiB) Viewed 2305 times

Before continuing, please update to latest https://github.com/FreeCAD/FreeCAD-Bund ... kly-builds

_FEM_still_no_BUG_TEST2_mesh_cleared.FCStd
(58.74 KiB) Downloaded 68 times
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