Thanks a lot, you are right, the correct field is iforbr.

I am now able to calculate the Stress on the cell surfaces.

I still have one problem. In order to obtain the force, I have to multiply the Stress by the boundary surface of the cell.

The surface value is given by surfbn(ifac) if I am not wrong.

To check the consistency, I performed the following test to calculate the total boundary surface:

Code: Select all

```
s_tot = 0.d0
call getfbr('STRUCTURE_WALL', nlelt, lstelt)
do ilelt = 1, nlelt
ifac = lstelt(ilelt)
s_tot=s_tot+surfbn(ifac)
enddo
```

Is surfbn the right field to get the face surface?

Thank you very much in advance.

Best regards,

Daniele