How to provide user defined field variables to next increment

[Carol]

Hi all,

I'm using user subroutine USDFLD in order to calculate field variables. I want to use these field variables as dependencies for my material's behavior. That means, that the young's modulus changes according to my field variable.

But I read that field variables are only computed for the current increment and not stored. So I think I have to store my field variables as state variables within the USDFLD subroutine. Is that right?

I thougt about something like the following code, but it doesn't actually work, because the field variable is calucated properly, but still equal to zero at the beginning of each increment and I don't see any error messages.

I'd be glad, if anyone might help me with that problem!
Thanks a lot!
Carol

SUBROUTINE USDFLD(FIELD,STATEV,PNEWDT,DIRECT,T,CELENT,
& TIME,DTIME,CMNAME,ORNAME,NFIELD,NSTATV,NOEL,NPT,LA YER,
& KSPT,KSTEP,KINC,NDI,NSHR,COORD,JMAC,JMATYP,MATLAYO ,LACCFLG)
C
INCLUDE 'ABA_PARAM.INC'

CHARACTER*80 CMNAME, ORNAME
CHARACTER*3 FLGRAY(15)
DIMENSION FIELD(NFIELD), STATEV(NSTATV), DIRECT(3,3), T(3,3),
& TIME(2)
DIMENSION ARRAY(15), JARRAY(15), JMAC(*), JMATYP(*), COORD(*)

FIELD(1)=STATEV(1)

... calculation of FIELD(1) depending on the stresses, provided from the previous increment ...

STATEV(1)=FIELD(1)

RETURN
END

[Jorgen]

Your approach look fine to me.

- Did you specify the number of state variables using *Depvar?
- Have you checked out the example in Abaqus user subroutine reference manual in Section 1.1.43?

[Carol]

Dear Jorgen,

thanks for your reply!! I checked *Depvar (being equal to the number of state variables) and compared my example with the one mentioned in the Abaqus manual, but unfortunately that didn't help too much.

But actually I found the solution for my problem. Quite late, but still :-)
The step of my increment was too large, as I performed an nonlinear analysis. So my analysis always finished before the field variables could be stored.

Again thanks a lot for your aid!!!

Regards,
Carol