Reading the calculix manual, I found a card that allows to generate residual stresses at the beginning on the simulation.

CalculiX CrunchiX USER’S MANUAL version 2.13 (in page 291)

*6.11.7 Initial(residual) stresses*

In each integration point of an element a residual stress tensor can be specified

by the keyword *INITIAL CONDITIONS, TYPE=STRESS. The residual stress

should be defined before the first *STEP card.

In each integration point of an element a residual stress tensor can be specified

by the keyword *INITIAL CONDITIONS, TYPE=STRESS. The residual stress

should be defined before the first *STEP card.

and in page 406

Following line for TYPE=STRESS if USER is not specified:

Element number.

Integration point number.

*# (what is this?)*

Value of first stress component (xx) in the GLOBAL coordinate system x-y-z.

Value of second stress component (yy) in the GLOBAL coordinate system x-y-z.

Value of third stress component (zz) in the GLOBAL coordinate system x-y-z.

Value of fourth stress component (xy) in the GLOBAL coordinate system x-y-z.

Value of fifth stress component (xz) in the GLOBAL coordinate system x-y-z.

Value of sixth stress component (yz) in the GLOBAL coordinate system x-y-z.

Etc.

Repeat this line if needed. The stress components should be given in the form of second Piola-Kirchhoff stresses.

...

The idea is to apply solely to one element (e.g. one C3D10 tetrahedron) an initial residual stress. Imagine that we have a cantilever beam, we select solely one element, and this element contains a residual stress due to some errors during a manufacturing process.

How can I simulate that?

I assume that the input file code should be something like that:

Code: Select all

```
*INITIAL CONDITIONS, TYPE=STRESS
22,?,(xx),(yy),(zz),(xy),(xz),(yz) # element 22 6 values of the stress tensor
28,?,(xx),(yy),(zz),(xy),(xz),(yz) # element 28 6 values of the stress tensor
33,?,(xx),(yy),(zz),(xy),(xz),(yz) # element 33 6 values of the stress tensor
...
```

Anyone knows or have experience about that?

If it is not possible to do that, is there any other way for simulating (initial) residual stresses?

I was thinking on applying a known pressure force to all faces of one element and then simulate using *perturbation card...

best regards,

Ekaitz.

**EDIT: This question is related with my other doubts**https://forum.freecadweb.org/viewtopic.php?f=18&t=31489 and https://forum.freecadweb.org/viewtopic.php?f=18&t=31421