no proper input for contact stiffness

About the development of the FEM module/workbench.

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uwestoehr
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no proper input for contact stiffness

Post by uwestoehr »

Word size of FreeCAD: 64-bit, Version: 0.18.15780 (Git)
Build type: Release
Branch: master
Hash: f94e76c1116ec3b818961ff65131b3d86fa5b95e
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0

- create a contact constraint
- try to enter e.g. a contact stiffness of 500 MPa, so for example try to type in "500e6"

result: you cannot enter numbers in the form "xxey" or "xxe+y" or "xxGPa"

It would be nice if one sees for the constraint values the unit to avoid mistakes and it would be nice if inputs using exponents would be allowed.

In the constraint Pressure acting on a face this is already implemented nicely. So it would be nice if this is also taken for the contact constraint.
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bernd
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Re: no proper input for contact stiffness

Post by bernd »

I fully agree with you Uwe. The TaskPanels of the constraint objects for sure need some love. Feel free to open a bug report in this regard.
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uwestoehr
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Re: no proper input for contact stiffness

Post by uwestoehr »

bernd wrote: Wed Feb 06, 2019 10:40 am Feel free to open a bug report in this regard.
Done: issue #3819
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bernd
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Re: no proper input for contact stiffness

Post by bernd »

Rana
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Re: no proper input for contact stiffness

Post by Rana »

It is related to contact stiffness unit in FEM workbench ( FreeCAD 0.19 - 22611). As per Calculix manual it should be Force]/[Length] ^3.
In FEM workbench, it shows MPa. It should be updated to avoid confusion.

Thanks.
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Kunda1
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Re: no proper input for contact stiffness

Post by Kunda1 »

bernd wrote: Sun Feb 24, 2019 8:59 pm :bell:
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Please mark thread [Solved]
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ebrahim raeyat
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Re: no proper input for contact stiffness

Post by ebrahim raeyat »

Rana wrote: Thu Oct 15, 2020 10:04 am It is related to contact stiffness unit in FEM workbench ( FreeCAD 0.19 - 22611). As per Calculix manual it should be Force]/[Length] ^3.
In FEM workbench, it shows MPa. It should be updated to avoid confusion.

Thanks.
Yes, and after meshing the surface, for each element, it must be calculated individually according to area of each element with Force / Length.

@bernd
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