## FEM MESH HAS NO VOLUME ELEMENTS

About the development of the FEM module/workbench.

Moderator: bernd

thschrader
Posts: 1483
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

### Re: FEM MESH HAS NO VOLUME ELEMENTS

Hi cti2019,
I had a look at your model. Running a 3D-FEM analysis is
an overkill of work and not necessary. It is much easier to use
a frame program for such a problem
http://members.ziggo.nl/wolsink/
https://www.ftool.com.br/Ftool/

Your load case uses only vertical loading near by the knots of the structure.
The (static relevant) bending-moment in the beams is nearly zero, the load directly
runs into the columns. The complete structure will tilt, you must use anchors
at the floor (or more selfweight).

You can divide the 3D-structure into several 2D-subproblems (the yellow frame
for instance). Critical loading is horizontal / diagonal.
regards Thomas
tilt.JPG (71.84 KiB) Viewed 209 times
2D_frame.JPG (49.87 KiB) Viewed 209 times
thschrader
Posts: 1483
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

### Re: FEM MESH HAS NO VOLUME ELEMENTS

or the good old fashioned way "by hand"...
https://structx.com/frames.html
cti2019
Posts: 12
Joined: Fri Feb 08, 2019 4:14 pm

### Re: FEM MESH HAS NO VOLUME ELEMENTS

The problem is that the structure always yields in the 3 points indicated in green.
And I do not know if increasing the thickness of the tubular I can solve the problem.
Attachments
tilt.JPG (114.66 KiB) Viewed 202 times
thschrader
Posts: 1483
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

### Re: FEM MESH HAS NO VOLUME ELEMENTS

ah, ok.
But that means, that only a part of the whole structure is of interest.
Is there horizontal loading at the plate (especially perpendicular to plate)?
Before meshing: eliminate the bolts and some holes...
Use mesh refinement at the cracking zones.
remaining_problem.JPG (28.08 KiB) Viewed 198 times
refinement.JPG (21.71 KiB) Viewed 198 times
cti2019
Posts: 12
Joined: Fri Feb 08, 2019 4:14 pm

### Re: FEM MESH HAS NO VOLUME ELEMENTS

thschrader wrote:
Mon Feb 11, 2019 2:51 pm
Use mesh refinement at the cracking zones.
how can I do?
thschrader
Posts: 1483
Joined: Sat May 20, 2017 12:06 pm
Location: Germany

### Re: FEM MESH HAS NO VOLUME ELEMENTS

I unrefined your model, maybe this helps...
prova1_part.FCStd
(38 KiB) Downloaded 13 times
mesh-refinement:
mesh body
click on mesh in tree, select mesh refinement,
then select the lines you want to refine.
FEM_part.JPG (55.79 KiB) Viewed 192 times