×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

changing density for FGM in umat

changing density for FGM in umat

changing density for FGM in umat

(OP)
Hello friends,
Here is the Abaqus user subroutine for Functionally Graded Material with direct integration method. This Umat is based on S.H.Song's Umat. Obviously the coefficient AAA in calculating E is the ratio of young moduli of two sides of the plate. With this method, one can change young modulus through the thickness.

But I have problem with changing density through the thickness, meaning from density of ceramic to density of metal.
I would be grateful if anyone can help me. Any help would be appreciated.

*USER SUBROUTINES
SUBROUTINE UMAT(STRESS,STATEV,DDSDDE,SSE,SPD,SCD,
1 RPL,DDSDDT,DRPLDE,DRPLDT,
2 STRAN,DSTRAN,TIME,DTIME,TEMP,DTEMP,PREDEF,DPRED,CMNAME,
3 NDI,NSHR,NTENS,NSTATEV,PROPS,NPROPS,COORDS,DROT,PNEWDT,
4 CELENT,DFGRD0,DFGRD1,NOEL,NPT,LAYER,KSPT,KSTEP,KINC)
C
INCLUDE 'ABA_PARAM.INC'
C
CHARACTER*80 CMNAME
DIMENSION STRESS(NTENS),STATEV(NSTATEV),
1 DDSDDE(NTENS,NTENS),DDSDDT(NTENS),DRPLDE(NTENS),
2 STRAN(NTENS),DSTRAN(NTENS),TIME(2),PREDEF(1),DPRED(1),
3 PROPS(NPROPS),COORDS(3),DROT(3,3),DFGRD0(3,3),DFGRD1(3,3)
C
PARAMETER (ONE=1.0D0, TWO=2.0D0)
C Determine material properties based on global coordinates of gauss points.
C COORDS(1) is X-coordinates of gauss points.
C COORDS(2) is Y-coordinates of gauss points.
C COORDS(3) is Z-coordinates of gauss points.
C PROPS is defined by users.
C The function can be also defined by users.
C
C------------- CHNGE -------------------------------------------------------------------------------C
C---------------------------------------------------------------------------------------------------C
E=PROPS(1)*EXP(AAA*COORDS(1))
V=PROPS(2)
C---------------------------------------------------------------------------------------------------C
C---------------------------------------------------------------------------------------------------C
C
C Determine Lame's constantes
C amu is mu
C alambeda is lambda
AMU=E/2.0d0/(1.0d0+V)
ALAMBDA=E*V/(1.0d0+V)/(1.0d0-2*V)
C
C
C Determine the tangant or Jacobian matrix
C
C NDI is number of normal stresses
C NSHR is number of shear stresses
C NTENS is dimension of constitutive matrix
C
C

DO I=1,NDI
DO J=1,NDI
if (I.eq.J) then
ddsdde(I,I)=ALAMBDA+2*AMU
else
ddsdde(I,J)=ALAMBDA
endif
ENDDO
ENDDO
DO I=NDI+1,NTENS
ddsdde(I,I)=AMU
ENDDO
C
C Determine the stress and update the stress
C
DO I=1,NTENS
DO J=1,NTENS
STRESS(I)=STRESS(I)+ddsdde(I,J)*DSTRAN(J)
ENDDO
ENDDO
C
RETURN
END

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources