Help with USDFLD&HETVAL Subroutines

[anto_772]

Hi guys, I'm trying to develop a USDFLD subroutine for a coupled thermal-electrical analysis. The goal of the subroutine is to determinate the decomposition grade as a function of the temperature of a composite. It seems to be easy but I am having some problems.

The grade of decomposition ''C''(DAMAGE) is calculate as follow:

D = (T-Ti)/(Tf-Ti), where Ti=573K and Tf=873K (Range of matrix decomposition temperature). T is the temperature at the current time increment

The thing is that it's the first time I develop a subroutine and I think I might be doing some mistakes, since abaqus cant compile it.
I'm just trying to set up a condition in which each node remains with the greater decomposition grade through the total step time.
I also want to plot the distribution of this grade of decomposition over my model.Please if someone is familiar to this type of subroutine and can check it out...

SUBROUTINE USDFLD(FIELD,STATEV,PNEWDT,DIRECT,T,CELENT,
1 TIME,DTIME,CMNAME,ORNAME,NFIELD,NSTATV,NOEL,NPT,LAYER,
2 KSPT,KSTEP,KINC,NDI,NSHR,COORD,JMAC,JMATYP,MATLAYO,LACCFLA)
C
INCLUDE 'ABA_PARAM.INC'
C
CHARACTER*80 CMNAME,ORNAME
CHARACTER*3 FLGRAY(15)
DIMENSION FIELD(NFIELD),STATEV(NSTATV),DIRECT(3,3),
1 T(3,3),TIME(2)
C
DIMENSION ARRAY(15),JARRAY(15),JMAC(*),JMATYP(*),COORD(*)
C
DAMAGE=STATEV(1)
C Get temperatures from previous increment
CALL GETVRM('TEMP',ARRAY,JARRAY,FLGRAY,JRCD,JMAC,JMATYP,
& MATLAYO,LACCFLA)
TEMP=ARRAY(1)
TEMP=TEMP(1)
C
REAL Ti,Tf
Ti=573
Tf=873
IF (TEMP.GT.Ti) THEN
IF (TEMP.LT.Tf) THEN
DAMAGE=((TEMP-Ti)/(Tf-Ti))
ELSE IF (TEMP.GT.Tf) THEN
DAMAGE=1.D0
ELSE IF (TEMP.LT.Ti) THEN
DAMAGE=0.D0
ENDIF
STATEV(1)=DAMAGE
ENDIF
FIELD(1)=DAMAGE
STATEV(1)=FIELD(1)
RETURN
END

Then I want to develop a HETVAL subroutine that simulate the exotermic flow generated after this decomposition with the Arrhenius equation as follow:

Flux = Hv*dC/dt where Hv(J/kg) is latent heat of phase change(value I have)
dC/dt= k(1-C)^n where C is the decomposition grade calculated in the USDFLD subroutine (passed to HETVAL in each increment)
k(T)=Aexp(-Ea/RT) where A=3x10^15 (1/s); Ea= 180(kJ/molK); n03.5; R=8,314(J/molK); C=grade of decomposition calculated in USFLD(DAMAGE)

SUBROUTINE HETVAL(CMNAME,TEMP,TIME,DTIME,STATEV,FLUX,
1 PREDEF,DPRED)
C
INCLUDE 'ABA_PARAM.INC'
C
CHARACTER*80 CMNAME
C
DIMENSION TEMP(2),STATEV(*),PREDEF(*),TIME(2),FLUX(2),
1 DPRED(*)
C Get temperatures from previous increment
CALL GETVRM('TEMP',ARRAY,JARRAY,FLGRAY,JRCD,JMAC,JMATYP,
& MATLAYO,LACCFLA)
TEMP=ARRAY(1)
TEMP=TEMP(1)
REAL Hv,A0,Ea,R,n
C=STATEV(1)
Hv=324.0
A0=3E15
Ea=130E3
R=8.314
n=3.5
Ti=573
Tf=873
IF (TEMP.GT.Ti) THEN
IF (TEMP.LT.Tf) THEN
k=A**(-Ea/R*TEMP)
dC=k*((1-STATVE(1)**n)
FLUX(1)=Htr*dC
ELSE
FLUX(1)=0.D0
ENDIF
ENDIF
RETURN
END
A question I have is if this flux summs to the heat flux generated by Joule effect??(I'm running a lightning strike simulation, the current flows through the material and it heated up because of Joule effect)
Any help is welcome. Thank you guys!!

 

[vazaar]

I think that if you have a compilation error you have to check for syntax-mistakes in your code. Anaqus creates a log file in your directory (jobname.log). If you open that it tells you the reason why it can not compile (e.g. EXAMPLE.for(27): error #5082: Syntax error, found ')' when expecting one of: ( % [ : . = =>
STATEV1) = 4 ). Maybe you missed some brackets or used wrong names.

Also did you succeed in linking Abaqus with the Fortran-compiler and VS-code? If you run abaqus verrtification from the start menu it tells you if Abaqus and the compiler are linked correctly.