Centrifugal Force Simulation

About the development of the FEM module/workbench.

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akeyokey
Posts: 27
Joined: Fri Feb 17, 2017 6:13 pm

Re: Centrifugal Force Simulation

Post by akeyokey »

fandaL wrote: The last three numbers 0.0, 0.0, 1.0 are not a normal vector. It is "normalized" axis vector, which means that it is a vector in direction of the rotation axis with length equal to 1.
In this case the rotation axis is in Z direction.

Ok I understand. But if i read the last message of this thread : https://forum.freecadweb.org/viewtopic.php?t=15157
So there is a mistake on this code? The example is a beam turning around the line, if i'm not wrong. The code used is :

Code: Select all

*DLOAD
Eall,CENTRIF,100000.,0.,0.,0.,0.,1.,0.
So it will be in this case too the same of mine example?

Code: Select all

*DLOAD
Eall,CENTRIF,100000.,0.,0.,0.,0.,0.,1.
fandaL
Posts: 440
Joined: Thu Jul 24, 2014 8:29 am

Re: Centrifugal Force Simulation

Post by fandaL »

akeyokey wrote:Ok I understand. But if i read the last message of this thread : https://forum.freecadweb.org/viewtopic.php?t=15157
So there is a mistake on this code? The example is a beam turning around the line, if i'm not wrong. The code used is :

Code: Select all

*DLOAD
Eall,CENTRIF,100000.,0.,0.,0.,0.,1.,0.
Looking at example "beam_centrifugal_load.FCStd"
You are true, according to the file, where axis is demonstrated with line in Z direction, it should be 0, 0, 1 instead of 0, 1, 0.
It contains a beam in X direction, so it yields same results for Z rotation axis (0, 0, 1) as well as Y (0, 1, 0).
akeyokey wrote:So it will be in this case too the same of mine example?

Code: Select all

*DLOAD
Eall,CENTRIF,100000.,0.,0.,0.,0.,0.,1.
Yes
ulrich1a
Veteran
Posts: 1957
Joined: Sun Jul 07, 2013 12:08 pm

Re: Centrifugal Force Simulation

Post by ulrich1a »

akeyokey wrote:Thanks you for helping me, first question when i open your files i get this error on freecad 0.17 system : windows 10

Code: Select all
<unknown exception traceback><type 'exceptions.ImportError'>: No module named PyObjects._FemSolverCalculix
<unknown exception traceback><type 'exceptions.ImportError'>: No module named PyObjects._FemMaterial
<unknown exception traceback><type 'exceptions.ImportError'>: No module named PyObjects._FemConstraintSelfWeight
<unknown exception traceback><type 'exceptions.ImportError'>: No module named PyObjects._FemResultMechanical
<unknown exception traceback><type 'exceptions.ImportError'>: No module named PyGui._ViewProviderFemSolverCalculix
<unknown exception traceback><type 'exceptions.ImportError'>: No module named PyGui._ViewProviderFemConstraintSelfWeight
<unknown exception traceback><type 'exceptions.ImportError'>: No module named PyGui._ViewProviderFemMaterial
<unknown exception traceback><type 'exceptions.ImportError'>: No module named PyGui._ViewProviderFemResultMechanical
I should not have compiled the latest version of FreeCAD before doing this. There where a some changes regarding the FEM-workbench between FreeCAD version 0.17.10150 and FreeCAD version 0.17.10424.

You may need to delete the whole analysis stuff and make it again. Or get 0.17.10423 from the download page. (I have one extra commit needed for my system to compile FreeCAD.)

Ulrich
akeyokey
Posts: 27
Joined: Fri Feb 17, 2017 6:13 pm

Re: Centrifugal Force Simulation

Post by akeyokey »

Hello, i don't want to create a new topic, because it is the same idea.

I would like to ask you, where can i find the algorithm of "DLOAD CENTRIF" to understand how calculix find the solution.
fandaL
Posts: 440
Joined: Thu Jul 24, 2014 8:29 am

Re: Centrifugal Force Simulation

Post by fandaL »

In the ccx manual there is not much about the algorithm.
http://www.feacluster.com/CalculiX/ccx_ ... de227.html
http://www.feacluster.com/CalculiX/ccx_ ... de175.html
so if you want to go deeper, you can search in some book about FEM theory or ask on CalculiX mailing list.
https://groups.yahoo.com/neo/groups/calculix/info
ulrich1a
Veteran
Posts: 1957
Joined: Sun Jul 07, 2013 12:08 pm

Re: Centrifugal Force Simulation

Post by ulrich1a »

There is a book from the author of Calculix: http://eu.wiley.com/WileyCDA/WileyTitle ... 57528.html

Then there is the Calculix source code, which is free to look into. ;)

Ulrich
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akeyokey
Posts: 27
Joined: Fri Feb 17, 2017 6:13 pm

Re: Centrifugal Force Simulation

Post by akeyokey »

Thanks you for answers.
joha2
Posts: 303
Joined: Tue Oct 11, 2016 9:48 pm

Re: Centrifugal Force Simulation

Post by joha2 »

Nice overview @ulrich. Did you buy this book? Seems rather expensive :-(
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