combined contact thermomechanical analysis

About the development of the FEM module/workbench.

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thschrader
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combined contact thermomechanical analysis

Post by thschrader »

Hello,
the controlling-engineer got me... ;)
I must calculate a tube connection with flanges and prestressed bolts.
(steel S235, all bolts M20 10.9, prestressing 160 kN each bolt)
Running a contact analysis without prestressing works fine.
When "cooling" the bolt (-180 K) to simulate prestressing, I get strange results.
Some questions:
When running the thermomechanical analysis including the contact definition,
it seems ccx does not detect the contact option (but it is written in the inp).
For contact analysis gmsh with 1.order elements is ok. Right?
But for stress analysis I need 2.order elements...
What value must I use for the contact-stiffness: stiffness=E-steel?

In ccx-manual v14 chapter 7.93 there is a pretension option, how can I use this?
Thomas
18065_Flansch_oben_Vorspannung.FCStd
(58.12 KiB) Downloaded 33 times
Bolt_without_prestressing.JPG
Bolt_without_prestressing.JPG (53.25 KiB) Viewed 1188 times
Bolt_cooling.JPG
Bolt_cooling.JPG (79.85 KiB) Viewed 1188 times
ccx_pretension.JPG
ccx_pretension.JPG (22.59 KiB) Viewed 1188 times
UR_
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Re: combined contact thermomechanical analysis

Post by UR_ »

A screw joint with pretension is shown in this example:

https://forum.freecadweb.org/viewtopic. ... on#p266772

It works without *PRETENSION card ;)
thschrader
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Re: combined contact thermomechanical analysis

Post by thschrader »

UR_ wrote: Thu May 02, 2019 4:35 pm A screw joint with pretension is shown in this example:
https://forum.freecadweb.org/viewtopic. ... on#p266772
It works without *PRETENSION card ;)
Sorry, I couldnt remember the post ;)
To "shorten" the bolt works fine. Prestressing a M20 bolt with 160 kN
gives approx 460 MPa sigma-z in the bolt. The deflection/stress in
the flange-plate is no problem ==> controlling-engineer will be happy.
Flanschsegment mit Fv und Last.JPG
Flanschsegment mit Fv und Last.JPG (75.66 KiB) Viewed 1082 times
UR_
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Re: combined contact thermomechanical analysis

Post by UR_ »

thschrader wrote: Tue May 07, 2019 12:17 pm ==> controlling-engineer will be happy
happiness.png
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HarryvL
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Re: combined contact thermomechanical analysis

Post by HarryvL »

thschrader wrote: Tue May 07, 2019 12:17 pm
UR_ wrote: Thu May 02, 2019 4:35 pm A screw joint with pretension is shown in this example:
https://forum.freecadweb.org/viewtopic. ... on#p266772
It works without *PRETENSION card ;)
Sorry, I couldnt remember the post ;)
To "shorten" the bolt works fine. Prestressing a M20 bolt with 160 kN
gives approx 460 MPa sigma-z in the bolt. The deflection/stress in
the flange-plate is no problem ==> controlling-engineer will be happy.
Flanschsegment mit Fv und Last.JPG
Cool picture Thomas. What graphical software is this?
thschrader
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Re: combined contact thermomechanical analysis

Post by thschrader »

HarryvL wrote: Tue May 07, 2019 2:21 pm Cool picture Thomas. What graphical software is this?
paraview, honey :)
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bernd
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Re: combined contact thermomechanical analysis

Post by bernd »

:D
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bernd
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Re: combined contact thermomechanical analysis

Post by bernd »

good to have the controlling engineer, you would not have posted this if he would not have claimed ... :mrgreen: :shock:
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HarryvL
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Re: combined contact thermomechanical analysis

Post by HarryvL »

thschrader wrote: Tue May 07, 2019 3:38 pm
HarryvL wrote: Tue May 07, 2019 2:21 pm Cool picture Thomas. What graphical software is this?
paraview, honey :)
How did you get the vertical distance scale overlays?
thschrader
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Re: combined contact thermomechanical analysis

Post by thschrader »

HarryvL wrote: Tue May 07, 2019 4:32 pm How did you get the vertical distance scale overlays?
See picture, enable "Show Axis".
At the moment I use paraview 4.0, newer versions crash, I have problems
with my graphics driver. FC 0.18 and above crashing too, FC 0.17 Roland works.
No idea why...
cube_axis.JPG
cube_axis.JPG (126.03 KiB) Viewed 955 times
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