Support for beam elements

Hello everyone.

I want to ask for the support of beam elements in the PrePoMax software. Even though CalculiX has some bugs regarding 1D elements (with many being corrected in the last release), it is pretty helpful to have them for slender structures modeling alongside shells. I work on a daily basis with beams and I would appreciate a lot if they could be implemented in this amazing software.

Best regards,

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They are surely planned to be added in the future. For now, you can use them in the FreeCAD FEM workbench.

More about beams in PrePoMax: UNV import to support line element (beam)

indeed, beam element in CalculiX only have several shapes but advanced (contact and nonlinearity material/geometry, static & dynamics, stability) and one general section is limited in capabilities (linear static only).

Possible beam element shape and type to be implemented in PrePoMax are:

  • rectangle
  • circle
  • pipe
  • box
  • user (general)
  • composed (experimental)

the last type is composed have problems in section force output, but working normally in previous versions.

it has disadvantages in over stiffening the model, but can be acceptable in case of slender (long) beam. Also, stiffness modification based on modulus of elasticity can be adjusted by reduction to comply.

probably, meshing of 1D element is better to do internally in PrePoMax, so a selection and grouping based on shape is easier to manage.

Do you know if this problem described in the thread you’ve posted still occurs in CCX 2.21? I would like to investigate this a little more when I have time.

i’m seek previous version of CalculiX which known to be working, and lost. but i’ts not a problem in 3D stress output.

to know work around of composed beam, it can be found on official test files named beamcom.inp i copied below,

**   Structure: cantilever beam.
**   Test objective: B32 elements, composite beam.
       1, -1.49012e-08,  0.00000e+00,  0.00000e+00 
       2,  1.00000e+00,  0.00000e+00,  0.00000e+00 
       3,  5.00000e-01,  0.00000e+00,  0.00000e+00 
       4,  2.00000e+00,  0.00000e+00,  0.00000e+00 
       5,  1.50000e+00,  0.00000e+00,  0.00000e+00 
     1,      1,      3,      2
     2,      2,      5,      4
     3,      1,      3,      2
     4,      2,      5,      4
0.05, 0.08
0.05, 0.08

i changed request output to be section forces, still shown some problems in summation at end nodes of beam element (1,2,4) but not at mid-nodes (3,5) .

Do you mean 2.20? It’s still available here:
You can download older versions by just changing the number in the link.

It’s best to report any issues here: Issues · Dhondtguido/CalculiX · GitHub

Fortunately, several nasty bugs, including some related to beams, were fixed in 2.21.

not really sure exactly versions known works, i made many tests in year of 2016. So, the version is about 2.10 and before.

indeed, i’m thinking to submit issue but probably a report test case and shown a version’s known working can be valuable info to developer.

maybe i’m not remembered properly, still questioning. Currently, i do test in versions 2.8p2 and 2.90 but still shown not working properly at section force output of composed beams.

2023-10-03 19_10_15-C__Windows_system32_cmd.exe

2023-10-03 19_09_22-C__Windows_system32_cmd.exe