Symmetrical Load| Asymmetrical stress output

1

Hello People of the Internet.

This Semester we were introduced to calculix. As of now I struggle with truss elements. As an exercise I created a simple table structure. The INP File is the following
*HEADING
Model: T3D2 Example, Nodal Load
*NODE, NSET=Nall
1, -2.0e3, 2.0e3, 0.0e3
2, 2.0e3, 2.0e3, 0.0e3
3, 2.0e3, 2.0e3, 4.0e3
4, -2.0e3, 2.0e3, 4.0e3
5, 0.0e3, 2.0e3, 4.0e3
6, -2.0e3, -2.0e3, 4.0e3
7, 2.0e3, -2.0e3, 4.0e3
8, 0.0e3, -2.0e3, 4.0e3
9, -2.0e3, -2.0e3, 0.0e3
10, 2.0e3, -2.0e3, 0.0e3
*ELEMENT, TYPE=T3D2, ELSET=Balken
1, 1, 4
2, 2, 3
3, 3, 5
4, 4, 5
5, 4, 6
6, 5, 8
7, 3, 7
8, 6, 8
9, 7, 8
10, 6, 9
11, 7, 10
*BOUNDARY
1,1,3
2,1,3
9,1,3
10,1,3
*MATERIAL,NAME=EL
*ELASTIC
7e4,0.34
*SOLID SECTION,ELSET=Balken,MATERIAL=EL
2.5e4
*STEP
*STATIC
*CLOAD
1,3,-1E+03
2,3,-1E+03
3,3,-1E+03
4,3,-1E+03
5,3,-1E+03
6,3,-1E+03
7,3,-1E+03
8,3,-1E+03
9,3,-1E+03
10,3,-1E+03
*NODE PRINT,NSET=Nall
U, RF
*EL PRINT,ELSET=Balken
S
*NODE FILE, OUTPUT=3D
U
*EL FILE
S
*END STEP
As you can see. The Load is symmetrical, yet my von-mises stress is asymmetrical. Are these just calculation problems or is something wrong with my input file. Thank you for every answer.
Here is the stress output

Stress
Stress1423Ă—997 16.3 KB

2

hello,
how looks deformation?
maybe these can help. It should be symmetrical too?
wbr

3

They are asymmetrical as well. Is there a possibility that it doesnt work correctly because I am using a windows adaptation?

Pic2
Pic2917Ă—914 9.78 KB

4

Hello,
if you use truss elements,
your system is instabil
if you change to nlgeom= on
you maybe get an error
wbr

*STEP, NLGEOM

1 Like
5

maybe you change to beam elements

*HEADING
Model: T3D2 Example, Nodal Load
*NODE, NSET=Nall
1, -2.0e3, 2.0e3, 0.0e3
2, 2.0e3, 2.0e3, 0.0e3
3, 2.0e3, 2.0e3, 4.0e3
4, -2.0e3, 2.0e3, 4.0e3
5, 0.0e3, 2.0e3, 4.0e3
6, -2.0e3, -2.0e3, 4.0e3
7, 2.0e3, -2.0e3, 4.0e3
8, 0.0e3, -2.0e3, 4.0e3
9, -2.0e3, -2.0e3, 0.0e3
10, 2.0e3, -2.0e3, 0.0e3
*ELEMENT, TYPE=B31, ELSET=Balken
1, 1, 4
2, 2, 3
3, 3, 5
4, 4, 5
5, 4, 6
6, 5, 8
7, 3, 7
8, 6, 8
9, 7, 8
10, 6, 9
11, 7, 10
*BOUNDARY
1,1,3
2,1,3
9,1,3
10,1,3
*MATERIAL,NAME=EL
*ELASTIC
7e4,0.34
*BEAM SECTION,MATERIAL=EL,ELSET=Balken,SECTION=RECT
100,100
1,1,1
*STEP,nlgeom
*STATIC, SOLVER=SPOOLES
*CLOAD
1,3,-1E+03
2,3,-1E+03
3,3,-1E+03
4,3,-1E+03
5,3,-1E+03
6,3,-1E+03
7,3,-1E+03
8,3,-1E+03
9,3,-1E+03
10,3,-1E+03
*NODE PRINT,NSET=Nall
U, RF
*EL PRINT,ELSET=Balken
S
*NODE FILE, OUTPUT=3D
U
*EL FILE
S
*END STEP
1 Like