Fortran subroutine - global variable

[tundres]

Hi everybody,

I have made a heat source to model laser welding with the dflux subroutine and I would like to know, if it's possible to define some global variables.
What I am trying to accomplish is to adapt my heat source if for example any point of the model reach a defined temperature. Is that possible?

Thanks in advance!

 

[vumat721]

You should be able to hard code your limiting value into your Dflux routine.

 

[DanStro]

I am not too familiar with user defined subroutines but I think Depvar's are global (in the sense of the material anyway). Maybe that is what you need to define, then have your subroutine grab them when needed.

HTH

 

[tundres]

Hey, I am glad to read some ideas:
To vumat721: your solution could work if I am able to get the temperature of a determined node. In this case, I would able to define the behaviour of the routine with the limiting value, in my case the temperature of the node (hard coded).

To DanStro: I didn't know of the existence of Depvar, I have to look at the documentation but sounds promising. I will give it a try too.

Thank you very much for the Ideas, let's see what comes next

 

[vumat721]

Depvar is used to specify number of state variables (statev) within a material subroutine (i.e UMAT, VUMAT, etc). I don't believe that DFLUX lets you have these kinds of state variables.

DFLUX gives you the temperature at the integration point. Perhaps you want to use UTEMP instead of DFLUX?

 

[tundres]

Hi vumat,

I finally found the way to accomplish that. In fact, it's possible to define global variables within a subroutine. I don't tried yet but I think you can exchange variables between subroutines with this "global variables" as well.

The solution was to read a Fortran Manual, also, in my example:
*USER SUBROUTINES
SUBROUTINE DFLUX(FLUX,SOL,KSTEP,KINC,TIME,NOEL,NPT,COORDS,
1 JLTYP,TEMP,PRESS,SNAME)
C
INCLUDE 'ABA_PARAM.INC'
C
DIMENSION COORDS(3),FLUX(2),TIME(2)
CHARACTER*80 SNAME

parameter (BoilingPoint = 2792)


real maxTemp,depth
COMMON /Control/maxTemp,depth

C###########################################
C Coordinates
C###########################################
x=COORDS(1)
y=COORDS(3)
z=COORDS(2)
C Coordinate conversion
r = sqrt(x ** 2 + y ** 2)

C Variable to store the temperature of the element. It will be used
C to check the max temperature of the Model.
tempmaxtemp = SOL

C If Statement to calc the max temperature in the Model
if(tempmaxtemp.ge.maxTemp)maxTemp=tempmaxtemp
...
---------------------------------------------------------
The variable maxTemp don't lose the value, also, global variable. With this method, I can know the max temperature of my Model.

Anyway, thanks for the help!

 

[vumat721]

Sounds good. I know Abaqus used to warn about using common blocks with subroutines. I don't remember the details, but maybe it's only an issue if you do a multi-cpu job? It looks like you can use "UEXTERNALDB" if you ever run into a problem with the common block not working as expected.