Displacement rotation not applied

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hdbondt
Posts: 27
Joined: Fri Jul 07, 2017 12:05 pm

Displacement rotation not applied

Postby hdbondt » Tue Aug 08, 2017 9:50 am

Using the displacement constraint I try to apply a torque on a femmesh but for some reason it is not included in the calculation.
I tried different rotation axis/ angels and played with the free/fixed setting but nothing changed.
Also when I type a rotation in the task view of the displacement both free and fixed are set to false.
If I use the property view I can set these parameters.
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selfmadeAFO.FCStd
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bernd
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Re: Displacement rotation not applied

Postby bernd » Tue Aug 08, 2017 10:01 am

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bernd
Posts: 8468
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Location: Zürich, Switzerland

Re: Displacement rotation not applied

Postby bernd » Tue Aug 08, 2017 10:05 am

hdbondt wrote:
Tue Aug 08, 2017 9:50 am
Using the displacement constraint I try to apply a torque on a femmesh
In FreeCAD ATM you can not apply constraints to femmeshes. You have to apply them on the Geometry. FreeCAD will then apply them to the femmesh at Solver input file writing.

bernd
hdbondt
Posts: 27
Joined: Fri Jul 07, 2017 12:05 pm

Re: Displacement rotation not applied

Postby hdbondt » Tue Aug 08, 2017 11:14 am

bernd wrote:
Tue Aug 08, 2017 10:05 am
In FreeCAD ATM you can not apply constraints to femmeshes. You have to apply them on the Geometry. FreeCAD will then apply them to the femmesh at Solver input file writing.
I apply the rotation on the geometry, it is visualised in the editor.
Image

But I get an error:
Invalid Signal signature: textchanged()
Base.FreeCADError: PyArg_ParseTuple failed. Invalid arguments used with setNodeByScalars



Thank you for the solutions, but they don't really help me.
I said torque, but my semantics are wrong, I want to do a displacement not apply a force
HoWil
Posts: 840
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Location: Austria

Re: Displacement rotation not applied

Postby HoWil » Tue Aug 08, 2017 2:42 pm

When I open your model and run it I get the following... is this what you want/expect?:
Screenshot from 2017-08-08 16-37-57.png
Screenshot from 2017-08-08 16-37-57.png (417.51 KiB) Viewed 1007 times
Are these settings for the Rotation in x, y, z correct/intended?
Screenshot from 2017-08-08 16-37-46.png
Screenshot from 2017-08-08 16-37-46.png (306.38 KiB) Viewed 1007 times
Which version of FC do you use? Please see https://forum.freecadweb.org/viewtopic. ... 212#p98139 .
BR,
HoWil
OS: Ubuntu 16.04.3 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.11740 (Git)/Daily-PPA
Build type: None
Branch: master
Hash: 6b05302c2e70f191a2a5787f55c5b549155b9824
Python version: 2.7.12
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.1.0
Locale: English/UnitedStates (en_US)
hdbondt
Posts: 27
Joined: Fri Jul 07, 2017 12:05 pm

Re: Displacement rotation not applied

Postby hdbondt » Wed Aug 09, 2017 7:32 am

HoWil wrote:
Tue Aug 08, 2017 2:42 pm
When I open your model and run it I get the following... is this what you want/expect?:
Yes, that's the same result as me.
But, that is not the result I wanted.
I'm trying to rotate the selected face in the displacement constraint.
Now it is only displaced by translation.
HoWil wrote:
Tue Aug 08, 2017 2:42 pm
Are these settings for the Rotation in x, y, z correct/intended?
Well, for now, any setting that would have a rotation in the resulting analysis is ok.
These settings is me trying different combinations of values.
HoWil wrote:
Tue Aug 08, 2017 2:42 pm
Which version of FC do you use? Please see https://forum.freecadweb.org/viewtopic. ... 212#p98139 .
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.11508 (Git)
Build type: Release
Branch: master
Hash: 087a1c1056d56e7bef0ce3bc6e367441fa0e3a9f
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.1.0
hdbondt
Posts: 27
Joined: Fri Jul 07, 2017 12:05 pm

Re: Displacement rotation not applied

Postby hdbondt » Mon Aug 21, 2017 2:37 pm

HoWil wrote:
Tue Aug 08, 2017 2:42 pm
When I open your model and run it I get the following... is this what you want/expect?:
I don't want to double post, but have you had a chance to look at it :)?
HoWil
Posts: 840
Joined: Sun Jun 14, 2015 7:31 pm
Location: Austria

Re: Displacement rotation not applied

Postby HoWil » Mon Aug 21, 2017 4:11 pm

Nop not really.
I just wanted to help to understand the question correctly.

I think the main point regarding your question is that the dialog box states "Rotations are only valid for Beam and Shell elements". So, I think it does not work for "real" 3d problems.
BR
Howil
UR_
Posts: 1013
Joined: Tue Jan 03, 2017 8:42 pm

Re: Displacement rotation not applied

Postby UR_ » Mon Aug 21, 2017 5:23 pm

If you need a rotational MPC, you will need some special approach.

* First joice is a bond to a rigid body. But this is at the moment not available, so we need a feature request in this regard.
* Second choice is you needs to imitate rigid body by a dummy.

This dummy need a significant higher young modulus and a cylindrical face.
A translational displacement needs to be defined first, which is transformed to a cylindrical coordinate system in a pending step.
So X-axis will be translated to radial displacement,
Y-axis will be translated to tangential displacement and Z-axis remains as cylinder's axis.

This will lead to this result:
rotational displacement.png
rotational displacement.png (170.23 KiB) Viewed 901 times

File:
torquetest.FCStd
(348.53 KiB) Downloaded 29 times

Done with:OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.11792 (Git)
Build type: Release
Branch: master
Hash: 7aec98ffb66065854a66d6d6715845fdbf0869a7
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.1.0
Locale: German/Germany (de_DE)
UR_
Posts: 1013
Joined: Tue Jan 03, 2017 8:42 pm

Re: Displacement rotation not applied

Postby UR_ » Mon Aug 21, 2017 7:40 pm

bernd wrote:ping
Hi bernd,

if this https://forum.freecadweb.org/viewtopic. ... 50#p178208
will be released, is it possible to buildup a shell from a circle and bond it onto this cube's topface for constraining directly with a rotational FemDisplacement? :?: