attempting to do FEM on hitch part

About the development of the FEM module/workbench.

Moderator: bernd

TLMMWF
Posts: 3
Joined: Wed Nov 13, 2019 10:49 pm

attempting to do FEM on hitch part

Postby TLMMWF » Wed Nov 13, 2019 10:55 pm

My info... COMPLETELY new to CAD with ZERO programming experience

OS: macOS 10.15
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.16131 (Git)
Build type: Release
Branch: (HEAD detached at 0.18.3)
Hash: 3129ae4296e40ed20e7b3d460b86e6969acbe1c3
Python version: 3.6.7
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)

so here's the problem:

I've built a 3d representation of the hitch on my truck for use to analyze stress on a tire carrier I'm designing. I think I've got the hitch correctly built but now the GMSH in FEM won't make a mesh of it for me to even begin checking the hitch itself for any flaws.

I've attached the file below... hopefully I'm not WAY off.. this took me basically all day.
chrisb
Posts: 19484
Joined: Tue Mar 17, 2015 9:14 am

Re: attempting to do FEM on hitch part

Postby chrisb » Wed Nov 13, 2019 11:02 pm

One day for a first part is not really bad.
The attached file is missing and I moved the post to FEM forum.
TLMMWF
Posts: 3
Joined: Wed Nov 13, 2019 10:49 pm

Re: attempting to do FEM on hitch part

Postby TLMMWF » Thu Nov 14, 2019 1:28 am

Chrisb,

thanks for the reply and moving it... I'll try again to attach the file, not sure why that didn't work
Swing out tire carrier.FCStd
(138.7 KiB) Downloaded 12 times
chrisb
Posts: 19484
Joined: Tue Mar 17, 2015 9:14 am

Re: attempting to do FEM on hitch part

Postby chrisb » Thu Nov 14, 2019 5:10 am

I'm not familiar with FEM, but your model is already in error: You start with a BaseFeature, but there is no source object to it. You should fix this and then try again with FEM.
UR_
Posts: 1013
Joined: Tue Jan 03, 2017 8:42 pm

Re: attempting to do FEM on hitch part

Postby UR_ » Thu Nov 14, 2019 7:55 am

No problems here with Gmsh

Screenshot 002.png
Screenshot 002.png (15.25 KiB) Viewed 245 times
Screenshot 003.png
Screenshot 003.png (277.1 KiB) Viewed 245 times
========================== Dump contents of mesh ==========================

1) Total number of nodes: 346707
2) Total number of edges: 3681
3) Total number of faces: 90610
4) Total number of polygons: 0
5) Total number of volumes: 193056
6) Total number of polyhedrons: 0

7) Total number of linear edges: 0
8) Total number of linear faces: 0
9) Total number of linear volumes: 0

10) Total number of quadratic edges: 3681
11) Total number of quadratic faces: 90610
11.1) Number of quadratic triangles: 90610
11.2) Number of quadratic quadrangles: 0
12) Total number of quadratic volumes: 193056
12.1) Number of quadratic hexahedrons: 0
12.2) Number of quadratic tetrahedrons: 193056
12.3) Number of quadratic prisms: 0
12.4) Number of quadratic pyramids: 0

===========================================================================


done with:
OS: Windows 10 (10.0)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.18714 (Git)
Build type: Release
Branch: master
Hash: a7ad04ba4aefb486fbc5e7c68da3dd488443b08c
Python version: 3.7.3
Qt version: 5.12.5
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: German/Germany (de_DE)
Gmsh 4.4.1

But caution, don't try solving by ccx on a poor ram utilised machine!
TLMMWF
Posts: 3
Joined: Wed Nov 13, 2019 10:49 pm

Re: attempting to do FEM on hitch part

Postby TLMMWF » Fri Nov 15, 2019 12:27 pm

Chrisb and UR.... I really need baby steps here to understand how this all works. What do you mean that it was already in error? What kind of problems do I look for there? And how’d you get it to mesh???
Jee-Bee
Posts: 1966
Joined: Tue Jun 16, 2015 10:32 am
Location: Netherlands

Re: attempting to do FEM on hitch part

Postby Jee-Bee » Fri Nov 15, 2019 12:59 pm

ChrisB is mentioning this:
2019-11-15 13_52_04-FreeCAD 0.19.png
2019-11-15 13_52_04-FreeCAD 0.19.png (18.33 KiB) Viewed 191 times
The exclamation mark means something is broken.

When you start using GMSH Mesher. you see the window showed by UR. if you use his settings it works well
Jee-Bee
Posts: 1966
Joined: Tue Jun 16, 2015 10:32 am
Location: Netherlands

Re: attempting to do FEM on hitch part

Postby Jee-Bee » Fri Nov 15, 2019 1:00 pm

i removed the BaseFeature since you use that shape twice...
Probably i broke something some where else... so just check all
Attachments
jbw_Swing_out_tire_carrier.FCStd
(121.09 KiB) Downloaded 5 times