Possible Bug in Section Print Flux and Anisotropic Materials

1

Hi all,
I am using Calculix 2.20 and ran into an error when running a heat transfer simulation and trying to record the heat flux through a defined surface. If I use an ORTHO solid material and add the line:
*SECTION PRINT, SURFACE=surface1, NAME=nsurface
FLUX

I get the error “*ERROR in materialdata_cond conductivity for fluids must be isotropic”, even though there are no fluids in my simulation file. If I make the solid material isotropic, the simulation runs fine. However, I need to have anisotropic materials for my simulations and need the heat flux through a defined surface.

Any advice on how to fix this issue would be greatly appreciated, thanks!

2

What if you remove that line - does it work ?

Can you share the input file for tests ?

4

Activating Section Print the analisys fails.
Example.

*NODE
1,0,0,0
2,1,0,0
3,1,1,0
4,0,1,0
5,0,0,1
6,1,0,1
7,1,1,1
8,0,1,1
9,0.5,0,0
10,0.5,0,1
11,0.5,1,0
12,0.5,1,1
*ELEMENT,TYPE=DC3D8
1,9,2,3,11,10,6,7,12
2,1,9,11,4,5,10,12,8
*NSET,NSET=OUT_N
2
3
6
7
*ELSET,ELSET=DEFAULT
1
2
*SURFACE,NAME=SURFACE_OUT
1,S4
*SURFACE,NAME=SURFACE_IN
2,S6
*MATERIAL,NAME=MATERIAL
*CONDUCTIVITY,TYPE=ORTHO
0.01,0.01,0.01,0
*SOLID SECTION,ELSET=DEFAULT,MATERIAL=MATERIAL
*STEP
*HEAT TRANSFER,STEADYSTATE
1,1,0,0
*CFLUX
4,11,0.25
1,11,0.25
5,11,0.25
8,11,0.25
*FILM
1,F4,272.15,1
*NODE FILE,GLOBAL=YES
NT
*EL FILE
HFL
*Node file
RFL
*El file
HFL,ENER

**SECTION PRINT,SURFACE=SURFACE_OUT,NAME=Heat_Flow2
**FLUX
*END STEP
5

Yes, it’s reported on GitHub: Error with *CONDUCTIVITY,TYPE=ORTHO and *SECTION PRINT · Issue #70 · Dhondtguido/CalculiX · GitHub

6

I don’t remember that bug post at all and I comment about it. :grimacing: