Learning Forum

[nikita.falke]

Hello, I am calculating axial forces in the link elements of a truss structure. I have used an APDL snippet to merge the nodes of all the links together (at the bottom of the post). When I solve the model, I do not get any error messages. Also, when the view is set to "Thick Shells and Beams", everything seems fine (see fig. 1).

However, when I disable "Thick Shells and Beams", the elements seem to be all over the place (fig. 2).

Are my results somehow influenced by that or is this a mere display feature?

Thanks in advance

APDL Command:

/PREP7

! 1. Select everything to ensure the merge affects the whole model
ALLSEL, ALL

! 2. Merge Nodes

NUMMRG, NODE, 0.020, , , LOW

! 3. Compress Node Numbers (Cleanup)
NUMCMP, NODE

! 4. Merge Elements (Optional but recommended for trusses)
NUMMRG, ELEM

! 5. Return control to solver
ALLSEL, ALL
FINISH
/SOLU

[ErKo]

Hi 

Seems you use WB/Mech.
No need for these commands that are not recom.

So instead use shared topology/multi-body part (Seacrh this up there are videos), to connect beam/line geom. - see here how it is done:

Frame Analysis - FEA using ANSYS - Lesson 4

Mesh with 1 division per member/line body (mesh size object )and set type to truss not default beam.

All the best

Erko

[nikita.falke]

Thank you for your response! I tried using both multi-body part in DM and Shared Topology. They both produced inconsistent outcomes: some nodes would merge and others would not, without any apparent system or error source. The code was the only way I could combine the structure into a whole.

Still the question remains: is the second image just a display artifact or does it imply actual structural problems in my model?

Thanks in advance!
Nikita