Should results be scaled for eigenmodes on result reading?

About the development of the FEM module/workbench.

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thschrader
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Re: Should results be scaled for eigenmodes on result reading?

Postby thschrader » Fri Feb 08, 2019 10:27 pm

You have n eigenmodes with with deflection.
The Eigenmode with the most deflection is scaled to 1.
The rest is (should be) lower. That is the spectrum.
Yes, the results should be scaled to the eigenmode with
max deformation.
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HarryvL
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Re: Should results be scaled for eigenmodes on result reading?

Postby HarryvL » Mon Feb 25, 2019 9:58 pm

HarryvL wrote:
Thu Feb 07, 2019 10:00 am
.... I therefore think it would be smarter to pre-scale as (for example) scale=0.01*model_range/max_disp. Then what is shown before user intervention is independent of units used.
This is what I get at the moment for scale factor 1.0 (can't go lower than that in result object). So it is necessary to apply some automatic scaling before letting the user decide ..... or allow scale factors smaller than 1.0.


Vibrating Column.png
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OS: Ubuntu 16.04.5 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.15788 (Git)
Build type: Unknown
Branch: femresultreading
Hash: 77c652a976e4255940dc4bc277697948b56eef0f
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)
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bernd
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Re: Should results be scaled for eigenmodes on result reading?

Postby bernd » Wed Feb 27, 2019 8:38 am

confirmed. Just put in the Calculix Standard examplt a force of 9E9 N and the factor 1 is far to big already ... This has been this way since start of FEM WB years ago ... Usually I never have more displacement then the geometry of the Part (which means scale factor < 1.0) but I must admit this should be possible too.

in my femresultreading branch I do calculate a scale factor.
https://github.com/berndhahnebach/FreeC ... al.py#L519 but still the gui does not allow factors < 1.0

BTW:the VTK wrap does allow factors < 1.0
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bernd
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Re: Should results be scaled for eigenmodes on result reading?

Postby bernd » Wed Feb 27, 2019 8:38 am

harry would you create an issue for this?
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bernd
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Re: Should results be scaled for eigenmodes on result reading?

Postby bernd » Wed Feb 27, 2019 8:50 am

you can use Python to set scale factors < 1.0 ... the last two lines of the code are the important ones

Code: Select all

doc = FreeCAD.open(FreeCAD.ConfigGet("AppHomePath") + 'data/examples/FemCalculixCantilever3D.FCStd')
doc.FemConstraintForce.Force = 9E9
doc.recompute()

import FemGui
FemGui.setActiveAnalysis(doc.Analysis)
from femtools import ccxtools
fea = ccxtools.FemToolsCcx()
fea.purge_results()
fea.run()

mesh_obj = doc.Result_mesh
result_obj =  doc.CalculiX_static_results

mesh_obj.ViewObject.setNodeDisplacementByVectors(result_obj.NodeNumbers, result_obj.DisplacementVectors)
mesh_obj.ViewObject.applyDisplacement(0.02)
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HarryvL
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Re: Should results be scaled for eigenmodes on result reading?

Postby HarryvL » Wed Feb 27, 2019 9:12 am

bernd wrote:
Wed Feb 27, 2019 8:38 am
harry would you create an issue for this?
OK
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HarryvL
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Re: Should results be scaled for eigenmodes on result reading?

Postby HarryvL » Fri Mar 01, 2019 12:15 am

bernd wrote:
Wed Feb 27, 2019 8:38 am
harry would you create an issue for this?
issue #3874