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[Solved] UMAT subroutine for 3d solid


bhulele
Posts: 6
Topic starter
(@bhulele)
Active Member
Joined: 4 years ago

Dear All,

I am okay in ABAQUS although trying subroutines for the first time.

I am trying to modify some codes available online, but the primary UMAT which I am posting here, is not working.

It shows no error in .log file but the job monitor says Problem during compilation - D:\Abaqus Work Directory\Trial_user_subroutine\try\Umat_mine.for

Please help me this, its very urgent.

Thanking you all,

Here is the code

I would also request Dr. Jurgen to give me some insight if possible for this specific code problem.

**

SUBROUTINE UMAT(STRESS, STATEV, DDSDDE, SSE, SPD, SCD, RPL,

1 DDSDDT, DRPLDE, DRPLDT, STRAN, DSTRAN, TIME, DTIME, TEMP, DTEMP,

2 PREDEF, DPRED, CMNAME, NDI, NSHR, NTENS, NSTATV, PROPS, NPROPS,

3 COORDS, DROT, PNEWDT, CELENT, DFGRD0, DFGRD1, NOEL, NPT, LAYER,

4 KSPT, KSTEP, KINC)

INCLUDE ABA_PARAM.INC

CHARACTER*80 CMNAME

DIMENSION STRESS(NTENS), STATEV(NSTATV), DDSDDE(NTENS, NTENS),

1 DDSDDT(NTENS), DRPLDE(NTENS), STRAN(NTENS), DSTRAN(NTENS),

2 PREDEF(1), DPRED(1), PROPS(NPROPS), COORDS(3), DROT(3, 3),

3 DFGRD0(3, 3), DFGRD1(3, 3)

C LOCAL ARRAYS

C ----------------------------------------------------------------

C EELAS - ELASTIC STRAINS

C EPLAS - PLASTIC STRAINS

C FLOW - DIRECTION OF PLASTIC FLOW

C -------------------------------------------

DIMENSION EELAS(6),EPLAS(6),FLOW(6), HARD(3)

PARAMETER(ZERO=0.D0, ONE=1.D0, TWO=2.D0, THREE=3.D0, SIX=6.D0,

& ENUMAX=.4999D0, NEWTON=10, TOLER=1.0D-6)

C

C ----------------------------------------------------------------

C UMAT FOR ISOTROPIC ELASTICITY AND ISOTROPIC MISES PLASTICITY

C

CANNOT BE USED FOR PLANE STRESS

C ----------------------------------------------------------------

C PROPS(1) - E

C PROPS(2) - NU

C PROPS(3..) - SYIELD AN HARDENING DATA

C

CALLS UHARD FOR CURVE OF YIELD STRESS VS. PLASTIC STRAIN

C ----------------------------------------------------

C ELASTIC PROPERTIES

EMOD=PROPS(1)

ENU= PROPS(2)

EBULK3=EMOD/(ONE-TWO*ENU)

EG2=EMOD/(ONE+ENU)

EG=EG2/TWO

EG3=THREE*EG

ELAM=(EBULK3-EG2)/THREE

C ELASTIC STIFFNESS

DO K1=1, NDI

DO K2=1, NDI

DDSDDE(K2, K1)=ELAM

END DO

DDSDDE(K1, K1)=EG2+ELAM

END DO

DO K1=NDI+1, NTENS

DDSDDE(K1, K1)=EG

END DO

C

C Example 5: Isotropic Hardening Plasticity RECOVER ELASTIC AND PLASTIC STRAINS AND ROTATE FORWARD

C ALSO RECOVER EQUIVALENT PLASTIC STRAIN

CALL ROTSIG(STATEV( 1), DROT, EELAS, 2, NDI, NSHR)

CALL ROTSIG(STATEV(NTENS+1), DROT, EPLAS, 2, NDI, NSHR)

EQPLAS=STATEV(1+2*NTENS)

C

C

C

CALCULATE PREDICTOR STRESS AND ELASTIC STRAIN

DO K1=1, NTENS

DO K2=1, NTENS

STRESS(K2)=STRESS(K2)+DDSDDE(K2, K1)*DSTRAN(K1)

END DO

EELAS(K1)=EELAS(K1)+DSTRAN(K1)

END DO

C CALCULATE EQUIVALENT VON MISES STRESS

SMISES=(STRESS(1)-STRESS(2))**2+(STRESS(2)-STRESS(3))**2

& +(STRESS(3)-STRESS(1))**2

DO K1=NDI+1,NTENS

SMISES=SMISES+SIX*STRESS(K1)**2

END DO

SMISES=SQRT(SMISES/TWO)

C

C Example 5: Isotropic Hardening Plasticity GET YIELD STRESS FROM THE SPECIFIED HARDENING CURVE

NVALUE=NPROPS/2-1

CALL UHARD(SYIEL0, HARD, EQPLAS, EQPLASRT,TIME,DTIME,TEMP,

& DTEMP,NOEL,NPT,LAYER,KSPT,KSTEP,KINC,CMNAME,NSTATV,

& STATEV,NUMFIELDV,PREDEF,DPRED,NVALUE,PROPS(3))

IF (SMISES.GT.(ONE+TOLER)*SYIEL0) THEN

C ACTIVELY YIELDING SEPARATE THE HYDROSTATIC FROM THE DEVIATORIC STRESS CALCULATE THE FLOW DIRECTION

SHYDRO=(STRESS(1)+STRESS(2)+STRESS(3))/THREE

DO K1=1,NDI

FLOW(K1)=(STRESS(K1)-SHYDRO)/SMISES

END DO

DO K1=NDI+1, NTENS

FLOW(K1)=STRESS(K1)/SMISES

END DO

C SOLVE FOR EQUIVALENT VON MISES STRESS AND EQUIVALENT PLASTIC STRAIN INCREMENT USING NEWTON ITERATION

SYIELD=SYIEL0

DEQPL=ZERO

DO KEWTON=1, NEWTON

RHS=SMISES-EG3*DEQPL-SYIELD

DEQPL=DEQPL+RHS/(EG3+HARD(1))

CALL UHARD(SYIELD,HARD,EQPLAS+DEQPL,EQPLASRT,TIME,DTIME,TEMP,

1 DTEMP,NOEL,NPT,LAYER,KSPT,KSTEP,KINC,CMNAME,NSTATV,

2 STATEV,NUMFIELDV,PREDEF,DPRED,NVALUE,PROPS(3))

IF(ABS(RHS).LT.TOLER*SYIEL0) GOTO 10

END DO

C WRITE WARNING MESSAGE TO THE .MSG FILE

C Example 5: Isotropic Hardening Plasticity

WRITE(7,2) NEWTON

2 FORMAT(//,30X,***WARNING - PLASTICITY ALGORITHM DID NOT ,

1 CONVERGE AFTER ,I3, ITERATIONS)

10 CONTINUE

DO K1=1,NDI

STRESS(K1)=FLOW(K1)*SYIELD+SHYDRO

EPLAS(K1)=EPLAS(K1)+THREE/TWO*FLOW(K1)*DEQPL

EELAS(K1)=EELAS(K1)-THREE/TWO*FLOW(K1)*DEQPL

END DO

DO K1=NDI+1,NTENS

STRESS(K1)=FLOW(K1)*SYIELD

EPLAS(K1)=EPLAS(K1)+THREE*FLOW(K1)*DEQPL

EELAS(K1)=EELAS(K1)-THREE*FLOW(K1)*DEQPL

END DO

EQPLAS=EQPLAS+DEQPL

SPD=DEQPL*(SYIEL0+SYIELD)/TWO

EFFG=EG*SYIELD/SMISES

EFFG2=TWO*EFFG

EFFG3=THREE/TWO*EFFG2

EFFLAM=(EBULK3-EFFG2)/THREE

EFFHRD=EG3*HARD(1)/(EG3+HARD(1))-EFFG3

DO K1=1, NDI

DO K2=1, NDI

DDSDDE(K2, K1)=EFFLAM

END DO

DDSDDE(K1, K1)=EFFG2+EFFLAM

END DO

DO K1=NDI+1, NTENS

DDSDDE(K1, K1)=EFFG

END DO

DO K1=1, NTENS

DO K2=1, NTENS

DDSDDE(K2, K1)=DDSDDE(K2, K1)+EFFHRD*FLOW(K2)*FLOW(K1)

END DO

END DO

ENDIF

DO K1=1, NTENS

STATEV(K1)=EELAS(K1)

STATEV(K1+NTENS)=EPLAS(K1)

END DO

STATEV(1+2*NTENS)=EQPLAS

C

RETURN

END

SUBROUTINE UHARD(SYIELD,HARD,EQPLAS,EQPLASRT,TIME,DTIME,TEMP,

1 DTEMP,NOEL,NPT,LAYER,KSPT,KSTEP,KINC,

2 CMNAME,NSTATV,STATEV,NUMFIELDV,

3 PREDEF,DPRED,NVALUE,TABLE)

INCLUDE ABA_PARAM.INC

CHARACTER*80 CMNAME

DIMENSION HARD(3),STATEV(NSTATV),TIME(*),

$ PREDEF(NUMFIELDV),DPRED(*),PROPS(*)

C

C USES LUDWIG EQUATION: SIGMA_YIELD = SIGMA_0 + K*EQPLAS^N

C d(SIGMA)/d(EQPLAS) = K*N*EQPLAS^(N-1)

C USER INPUT:

C THE MATERIAL UNKNOWNS PROPS 1 2 AND 3 ARE DEFINED IN ABAQUS NOT IN CODE, SO NO NEED TO DEFINE PROPS 1 2 3

C

PARAMETER(ZERO=0.D0, ONE=1.D0)

C

C CALCULATE

C

SYIELD=PROPS(4) + PROPS(5)*EQPLAS**PROPS(6)

HARD(1)=PROPS(5)*PROPS(6)*EQPLAS**(PROPS(6)-ONE)

HARD(2)=ZERO

HARD(3)=ZERO

GOTO 10

RETURN

END

Topic Tags
6 Replies
Jorgen
Posts: 3896
Moderator
(@jorgen)
Member
Joined: 2 years ago

What error messages do you see when you try to compile the code?

-Jorgen

Topic Tags
6 Replies
bhulele
Posts: 6
Topic starter
(@bhulele)
Active Member
Joined: 4 years ago

Dear Jurgen Sir,

Thanks for the reply.

I have however solved the problem.

I need another help from you.

I have written a GTN damage model in UMAT, but is there any way to make it non-local.

Can I get stresses of other elements to assign them weight factor and define a global damage instead of local formulation.

Please help.

With regards,

Abhishek

theDevils
Posts: 2
(@theDevils)
New Member
Joined: 5 years ago

Can you share your code for GTN model

[QUOTE=Tresca,13285]Dear Jurgen Sir,

Thanks for the reply.

I have however solved the problem.

I need another help from you.

I have written a GTN damage model in UMAT, but is there any way to make it non-local.

Can I get stresses of other elements to assign them weight factor and define a global damage instead of local formulation.

Please help.

With regards,

Abhishek[/QUOTE]

Hi Tresca,

I am new to UAMT. I am working on ductile damage behavior. I need your umat code written for GTN model. This would help to understand how to code for GTN model. Please reply me.

With regards

Sai Deepak N.

theDevils
Posts: 2
(@theDevils)
New Member
Joined: 5 years ago

Hi tresca,

I am new to UMAT. I am working on ductile damage model. I need your UMAT code for GTN model. I can use your code to understand better umat. Please reply. This will help me a lot.

Thank you

Sai Deepak N

msuhairil04
Posts: 21
(@msuhairil04)
Eminent Member
Joined: 4 years ago

hi,

is possible to simulat a friction law by umat

thank a lot

bhulele
Posts: 6
Topic starter
(@bhulele)
Active Member
Joined: 4 years ago

[USER=21497]sportivo_cae[/USER] I dont think so. I think friction would be applicable only to the contact region and it will also be dependent on the distance from the contact, so UMAT wouldnt help. I think there is a simple subroutine FRIC or something.

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