How to use Z88 in FEM?

Post here for help on using FreeCAD's graphical user interface (GUI).
Forum rules
and Helpful information
IMPORTANT: Please click here and read this first, before asking for help

Also, be nice to others! Read the FreeCAD code of conduct!
AhmedER
Posts: 19
Joined: Sun Mar 19, 2017 2:00 pm

Re: How to use Z88 in FEM?

Postby AhmedER » Sat Jul 08, 2017 11:12 am

bernd wrote:
Sat Jul 08, 2017 10:20 am
I get no results either. I need to have a closer look. This may take some time.

To try if your z88 runs in FreeCAD you could do the following.

- start FreeCAD
- go to start wb
- load 3D FEM example
- activate the analysis
- add an solver z88 object
- select the z88 solver
- click on the run analysis button
- a new result object should be created. You should get the same deformations as with Calculix

bernd
I did and it works with the 3D FEM example. When retrying my truss problem I noticed the following text in the Report view

"Edge femmesh will be exported as 3D truss element nr 4
{'ISFLAG': '1', 'INTORD': '0', 'INTOS': '0', 'IHFLAG': '0'}
Multiple beamsections for Z88 not yet supported!"

Does this mean that it doesn't support 2D beam elements and it converts it to 3D for analysis? Or does it mean that it just fails to analyze them entirely?
User avatar
Kunda1
Posts: 8461
Joined: Thu Jan 05, 2017 9:03 pm

Re: How to use Z88 in FEM?

Postby Kunda1 » Sat Jul 08, 2017 11:17 am

@bernd does Z88 have a unit test ?
Want to contribute back to FC? Checkout:
#lowhangingfruit | Use the Source, Luke. | How to Help FreeCAD | How to report FC bugs and features
User avatar
bernd
Posts: 10828
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

Re: How to use Z88 in FEM?

Postby bernd » Sat Jul 08, 2017 11:32 am

no, there is no unit test at the moment. :(

multiple beamsections not supported means you only can define one beam sections for all your 1D elements. The multiple beam sections are not implemented for z88 in FreeCAD.

Just saw it on your sceen, you have two beamsection objects, there can only be one for z88 atm.

bernd
User avatar
Kunda1
Posts: 8461
Joined: Thu Jan 05, 2017 9:03 pm

Re: How to use Z88 in FEM?

Postby Kunda1 » Sat Jul 08, 2017 11:39 am

bernd wrote:
Sat Jul 08, 2017 11:32 am
no, there is no unit test at the moment. :(
Should I open a FEM ticket for this ?
Want to contribute back to FC? Checkout:
#lowhangingfruit | Use the Source, Luke. | How to Help FreeCAD | How to report FC bugs and features
User avatar
bernd
Posts: 10828
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

Re: How to use Z88 in FEM?

Postby bernd » Sat Jul 08, 2017 11:43 am

Kunda1 wrote:
Sat Jul 08, 2017 11:39 am
bernd wrote:
Sat Jul 08, 2017 11:32 am
no, there is no unit test at the moment. :(
Should I open a FEM ticket for this ?
you could, but it is not somewhere near the top of my todo
User avatar
bernd
Posts: 10828
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

Re: How to use Z88 in FEM?

Postby bernd » Sat Jul 08, 2017 11:48 am

i would cal it fem solver calculix, and we will collect all z88 related stuff there.
User avatar
Kunda1
Posts: 8461
Joined: Thu Jan 05, 2017 9:03 pm

Re: How to use Z88 in FEM?

Postby Kunda1 » Sat Jul 08, 2017 12:01 pm

bernd wrote:
Sat Jul 08, 2017 11:48 am
i would cal it fem solver calculix, and we will collect all z88 related stuff there.
issue #3118
Want to contribute back to FC? Checkout:
#lowhangingfruit | Use the Source, Luke. | How to Help FreeCAD | How to report FC bugs and features
AhmedER
Posts: 19
Joined: Sun Mar 19, 2017 2:00 pm

Re: How to use Z88 in FEM?

Postby AhmedER » Sat Jul 08, 2017 12:55 pm

bernd wrote:
Sat Jul 08, 2017 11:32 am
no, there is no unit test at the moment. :(

multiple beamsections not supported means you only can define one beam sections for all your 1D elements. The multiple beam sections are not implemented for z88 in FreeCAD.

Just saw it on your sceen, you have two beamsection objects, there can only be one for z88 atm.

bernd

Even after I deleted one of the two beam elements and the error line disappeared I still get no results.

Instead this error appears
"Base.FreeCADError: PyArg_ParseTuple failed. Invalid arguments used with setNodeByScalars"
Attachments
TrussZ88real.fcstd
(11.46 KiB) Downloaded 15 times
User avatar
bernd
Posts: 10828
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

Re: How to use Z88 in FEM?

Postby bernd » Sun Jul 09, 2017 8:21 pm

Z88 in FreeCAD uses for 1D meshes a truss element, thus you should use seg2 elments and not have nodes between the edgends. Furthermore as far as i know constraint displacement is not supported. But anyway I could your example not get to run. What you could do is to check the error log of z88 it is in the working directory and its name is z88r.log

I attached an example from Z88 homepage. It runs in calculix and in z88

bernd
Attachments
b2--z88examples--seg2.fcstd
(59.11 KiB) Downloaded 42 times