Centrifugal Force Simulation
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Centrifugal Force Simulation
Hello I would like to simulate centrifugal force on propeller but I'm new on freeCAD and i don't find in FEM workbench the option so could you please give me some clues.
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.6706 (Git)
Build type: Release
Branch: releases/FreeCAD-0-16
Hash: f86a4e411ff7848dea98d7242f43b7774bee8fa0
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.6706 (Git)
Build type: Release
Branch: releases/FreeCAD-0-16
Hash: f86a4e411ff7848dea98d7242f43b7774bee8fa0
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17
Re: Centrifugal Force Simulation
It needs a bit hand work on .inp file which you need to open and modify before running an analysis.
Look here: https://forum.freecadweb.org/viewtopic.php?t=15157
Transform and self weight tools in the latest 0.17 version could help, but do not make all the work.
Look here: https://forum.freecadweb.org/viewtopic.php?t=15157
Transform and self weight tools in the latest 0.17 version could help, but do not make all the work.
Re: Centrifugal Force Simulation
use *DLOAD
See http://www.feacluster.com/CalculiX/ccx_ ... de227.html
I have see the term dload somwhere in FEM module but don't know how much is intergrated.
See http://www.feacluster.com/CalculiX/ccx_ ... de227.html
I have see the term dload somwhere in FEM module but don't know how much is intergrated.
Re: Centrifugal Force Simulation
Thanks for this clues, i will try it
Re: Centrifugal Force Simulation
On Calculix, define the element set to be subjected to the centrifugal loading. The magnitude is calculated as density multiplied by the square of the angular velocity (in radians/second). For axisymmetric problems the axis of rotation must be the global Z-axis, which must be specified as 0.0, 0.0, 0.0, 0.0, 1.0, 0.0.
Following line for centrifugal loading:
Element number or element set label.
CENTRIF
rotational speed square ($ \omega^2$)
Coordinate 1 of a point on the rotation axis
Coordinate 2 of a point on the rotation axis
Coordinate 3 of a point on the rotation axis
Component 1 of the normalized direction of the rotation axis
Component 2 of the normalized direction of the rotation axis
Component 3 of the normalized direction of the rotation axis
Example:
*DLOAD
Eall,CENTRIF,100000.,0.,0.,0.,1.,0.,0.
Following line for centrifugal loading:
Element number or element set label.
CENTRIF
rotational speed square ($ \omega^2$)
Coordinate 1 of a point on the rotation axis
Coordinate 2 of a point on the rotation axis
Coordinate 3 of a point on the rotation axis
Component 1 of the normalized direction of the rotation axis
Component 2 of the normalized direction of the rotation axis
Component 3 of the normalized direction of the rotation axis
Example:
*DLOAD
Eall,CENTRIF,100000.,0.,0.,0.,1.,0.,0.
Re: Centrifugal Force Simulation
Hi, just to complete the question, this is my approach (it does not involve FreeCAD, yet):
https://www.youtube.com/watch?v=tM-WBgG3YrA&t=2s
You can try it yourself online at http://www.caeplex.com
https://www.youtube.com/watch?v=tM-WBgG3YrA&t=2s
You can try it yourself online at http://www.caeplex.com
Re: Centrifugal Force Simulation
I have a little question more,
My beam is on the x axis. and my rotation axis is on the z axis. But I don't understand the three last parameters of "dload"?
This previous code is the normal of z?
If yes, those are also normal of z so how can i choose the correct one?
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.6706 (Git)
Build type: Release
Branch: releases/FreeCAD-0-16
Hash: f86a4e411ff7848dea98d7242f43b7774bee8fa0
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17
Code: Select all
*DLOAD
Eall,CENTRIF,70225.,0.,0.,17.5,1.,0.,0.
Code: Select all
1.,0.,0.
If yes, those are also normal of z so how can i choose the correct one?
Code: Select all
1.,1.,0.
0.,1.,0.
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.6706 (Git)
Build type: Release
Branch: releases/FreeCAD-0-16
Hash: f86a4e411ff7848dea98d7242f43b7774bee8fa0
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17
- Attachments
-
- Model3FBladeS.FCStd
- (541.59 KiB) Downloaded 84 times
Re: Centrifugal Force Simulation
It is really recommended to use a 0.17-developement version of FreeCAD in this case. Centrifugal load is still has not all available, but it is much easier to analyze your case.
I rotated your model by 45° and I increased the hub angle, to cover 90°. Both measures allow a convenient fixture of your model in space by the usage of the displacement constraints. I fixed the top face of the hub in z-direction and the cut-hub-faces in x respective y-direction.
These constraints takes care that the hub can only move in those ways, it will move in reality under load.
You need now only add a gravity-constraint and replace the one discussed line in the input file, to get the analysis.
Ulrich
OS: Debian GNU/Linux 8.7 (jessie)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.10424 (Git)
Build type: Release
Branch: Rueck6
Hash: 5c5537da737d55e77ecde65fda7d1ea6512ffe76
Python version: 2.7.9
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 7.1.0
I rotated your model by 45° and I increased the hub angle, to cover 90°. Both measures allow a convenient fixture of your model in space by the usage of the displacement constraints. I fixed the top face of the hub in z-direction and the cut-hub-faces in x respective y-direction.
These constraints takes care that the hub can only move in those ways, it will move in reality under load.
You need now only add a gravity-constraint and replace the one discussed line in the input file, to get the analysis.
Code: Select all
*DLOAD
**Eall,GRAV,9810,0.0,0.0,-1.0
Eall,CENTRIF,70225.,0.0,0.0,0.0,0.0,0.0,1.0
OS: Debian GNU/Linux 8.7 (jessie)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.10424 (Git)
Build type: Release
Branch: Rueck6
Hash: 5c5537da737d55e77ecde65fda7d1ea6512ffe76
Python version: 2.7.9
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 7.1.0
- Attachments
-
- result_cetrifugal_load.png (201.53 KiB) Viewed 4074 times
-
- Model3FBladeS_ulrich.fcstd
- (1011.71 KiB) Downloaded 72 times
Re: Centrifugal Force Simulation
Thanks you for helping me, first question when i open your files i get this error on freecad 0.17 system : windows 10ulrich1a wrote:It is really recommended to use a 0.17-developement version of FreeCAD in this case. Centrifugal load is still has not all available, but it is much easier to analyze your case.
I rotated your model by 45° and I increased the hub angle, to cover 90°. Both measures allow a convenient fixture of your model in space by the usage of the displacement constraints. I fixed the top face of the hub in z-direction and the cut-hub-faces in x respective y-direction.
These constraints takes care that the hub can only move in those ways, it will move in reality under load.
You need now only add a gravity-constraint and replace the one discussed line in the input file, to get the analysis.
UlrichCode: Select all
*DLOAD **Eall,GRAV,9810,0.0,0.0,-1.0 Eall,CENTRIF,70225.,0.0,0.0,0.0,0.0,0.0,1.0
OS: Debian GNU/Linux 8.7 (jessie)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.10424 (Git)
Build type: Release
Branch: Rueck6
Hash: 5c5537da737d55e77ecde65fda7d1ea6512ffe76
Python version: 2.7.9
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 7.1.0
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
Component 1 of the normalized direction of the rotation axis 0
Component 2 of the normalized direction of the rotation axis 0
Component 3 of the normalized direction of the rotation axis 1
Code: Select all
Eall,CENTRIF,70225.,0.0,0.0,0.0,0.0,0.0,1.0
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.10150 (Git)
Build type: Release
Branch: master
Hash: 978978f7dd1814083d7b9c9fc4267dba25f58a80
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.0.0
Re: Centrifugal Force Simulation
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.akeyokey wrote:And i don't understand why you choose :
Component 1 of the normalized direction of the rotation axis 0
Component 2 of the normalized direction of the rotation axis 0
Component 3 of the normalized direction of the rotation axis 1
Code: Select all
Eall,CENTRIF,70225.,0.0,0.0,0.0,0.0,0.0,1.0
In this case the rotation axis is in Z direction.