272 lines
No EOL
9.1 KiB
Fortran
272 lines
No EOL
9.1 KiB
Fortran
c Abaqus User Defined Material Subroutine - J. Grogan, 2011
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c -------------------------------------------------------------------
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subroutine vumat (
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c Read only -
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* nblock,ndir,nshr,nstatev,nfieldv,nprops,lanneal,stepTime,
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* totalTime,dt,cmname,coordMp,charLength,props,density,
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* strainInc,relSpinInc,tempOld,stretchOld,defgradOld,
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* fieldOld,stressOld, stateOld, enerInternOld,enerInelasOld,
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* tempNew, stretchNew, defgradNew, fieldNew,
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c Write only -
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* stressNew, stateNew, enerInternNew, enerInelasNew )
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c
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include 'vaba_param.inc'
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c
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dimension coordMp(nblock,3),charLength(nblock),props(nprops),
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1 strainInc(nblock,ndir+nshr),stressOld(nblock,ndir+nshr),
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2 stateOld(nblock,nstatev),stressNew(nblock,ndir+nshr),
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3 stateNew(nblock,nstatev),astr(nblock,ndir+nshr),
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4 rKE(3,3),enerInternNew(nblock), enerInternOld(nblock),
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5 density(nblock)
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c
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character*80 cmname
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c
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parameter (zero = 0.d0, one = 1.d0, two = 2.d0, three = 3.d0,
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* four = 4.d0,third = 1.d0 / 3.d0, half = 0.5d0, op5 = 1.5d0)
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c -------------------------------------------------------------------
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c Common blocks store element status and random number assigment.
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common active(400000)
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common randnum(400000)
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integer active
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real randnum
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c
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do k=1,nblock
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c -------------------------------------------------------------------
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c Update SDVs
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do i=1,9
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stateNew(k,i)=stateOld(k,i)
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enddo
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do i=23,30
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stateNew(k,i)=stateOld(k,i)
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enddo
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c -------------------------------------------------------------------
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c Get meterial properties from INP file and form 'C' matrix
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e = props(1)
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xnu = props(2)
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syield=props(3)
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b=props(4)
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q=props(5)
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twomu = e / ( one + xnu )
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thremu = op5 * twomu
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alamda = xnu * twomu / ( one - two * xnu )
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trace=strainInc(k,1)+strainInc(k,2)+strainInc(k,3)
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c -------------------------------------------------------------------
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c Linear elastic material for Abq/Explicit Packager
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if(abs(steptime)<=0.d0)then
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do i=1,3
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stressNew(k,i)=stressOld(k,i)
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* +twomu*strainInc(k,i)+alamda*trace
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enddo
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do i=4,6
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stressNew(k,i)=stressOld(k,i)+twomu*strainInc(k,i)
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enddo
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else
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c -------------------------------------------------------------------
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c Get Actual Trial Stress
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do i=1,3
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astr(k,i)=stateOld(k,9+i)
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* +twomu*strainInc(k,i)+alamda*trace
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enddo
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do i=4,6
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astr(k,i)=stateOld(k,9+i)+twomu*strainInc(k,i)
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enddo
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c -------------------------------------------------------------------
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c Partially Convert to Voigt Form
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smean = third*(astr(k,1)+astr(k,2)+astr(k,3))
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s11 = astr(k,1) - smean
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s22 = astr(k,2) - smean
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s33 = astr(k,3) - smean
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c -------------------------------------------------------------------
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c Get Von Mises Stress
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stateNew(k,19)=sqrt(op5*(s11*s11+s22*s22+s33*s33
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* +two*astr(k,4)*astr(k,4)+two*astr(k,5)*astr(k,5)
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* +two*astr(k,6)*astr(k,6)))
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c -------------------------------------------------------------------
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c Get Max Prin Stress
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rKE(1,1)=s11
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rKE(2,2)=s22
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rKE(3,3)=s33
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rKE(1,2)=astr(k,4)
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rKE(2,1)=astr(k,4)
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rKE(2,3)=astr(k,5)
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rKE(3,2)=astr(k,5)
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rKE(1,3)=astr(k,6)
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rKE(3,1)=astr(k,6)
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rq=s11*s22*s33
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rq=rq+2.d0*rKE(1,2)*rKE(2,3)*rKE(1,3)
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rq=rq-rKE(1,1)*rKE(2,3)*rKE(2,3)
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rq=rq-rKE(2,2)*rKE(1,3)*rKE(1,3)
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rq=rq-rKE(3,3)*rKE(1,2)*rKE(1,2)
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rq=rq/2.d0
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p=0.d0
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do i=1,3
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do j=1,3
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p=p+rKE(i,j)*rKE(i,j)
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enddo
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enddo
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p=p/6.d0
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if(p<1.e-6)then
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phi=(1.d0/3.d0)*(acos(0.d0)/2.d0)
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else
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if(abs(rq)>abs(p**(1.5)))then
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phi=0.d0
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else
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phi=(1.d0/3.d0)*acos(rq/p**(1.5))
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endif
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endif
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if(phi<0.)then
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phi=phi+acos(0.d0)/3.d0
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endif
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eig1=smean+2.d0*sqrt(p)*cos(phi)
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eig2=smean-sqrt(p)*(cos(phi)+sqrt(3.d0)*sin(phi))
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eig3=smean-sqrt(p)*(cos(phi)-sqrt(3.d0)*sin(phi))
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stateNew(k,16)=max(eig1,eig2,eig3)
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c -------------------------------------------------------------------
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c Recover Yield Surface
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if(stateOld(k,17)<=0.d0)then
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yieldOld=syield
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else
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yieldOld=stateOld(k,17)
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endif
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c -------------------------------------------------------------------
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c Update Hardening Parameters
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rold=q*(one-exp(-b*stateOld(k,18)))
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hard=b*(q-rold)
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c -------------------------------------------------------------------
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c Get equivalent plastic strain increment
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sigdif = stateNew(k,19) - yieldOld
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facyld = zero
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if(sigdif.gt.zero)facyld=one
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deqps=facyld*sigdif/(thremu+hard)
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c -------------------------------------------------------------------
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c Update Yield Surface and Eq. Plastic Strain
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yieldNew = yieldOld + hard * deqps
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stateNew(k,18) = stateOld(k,18) + deqps
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stateNew(k,17)= yieldNew
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c -------------------------------------------------------------------
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c Get Correction Factor for Trial Stress
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factor = yieldNew / ( yieldNew + thremu * deqps )
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c -------------------------------------------------------------------
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c Determine Actual Stress
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stateNew(k,10) = s11 * factor + smean
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stateNew(k,11) = s22 * factor + smean
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stateNew(k,12) = s33 * factor + smean
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stateNew(k,13) = astr(k,4) * factor
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stateNew(k,14) = astr(k,5) * factor
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stateNew(k,15) = astr(k,6) * factor
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c -------------------------------------------------------------------
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c Update Damage Parameter
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if(totaltime>=1.5)then
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call apply_damage(stateOld,stateNew,k,nblock,
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* nstatev,randnum,charlength,props,nprops,dt,
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* active,steptime,totaltime)
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endif
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c -------------------------------------------------------------------
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c Determine Element Stress (Returned to Abaqus)
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c Element Stress = Material Stress*(1-D)
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do i=1,6
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stressNew(k,i)=stateNew(k,9+i)*(one-statenew(k,21))
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enddo
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endif
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C Update the specific internal energy -
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stressPower = half * (
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1 ( stressOld(k,1)+stressNew(k,1) )*strainInc(k,1)
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1 + ( stressOld(k,2)+stressNew(k,2) )*strainInc(k,2)
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1 + ( stressOld(k,3)+stressNew(k,3) )*strainInc(k,3)
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1 + two*( stressOld(k,4)+stressNew(k,4) )*strainInc(k,4) )
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C
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enerInternNew(k) = enerInternOld(k)+ stressPower / density(k)
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c
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end do
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return
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end subroutine vumat
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c -------------------------------------------------------------------
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c
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c This subroutine updates the value of the damage parameter based on
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c corrosion and/or ductile damage evolution. J. Grogan, 2011.
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c
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subroutine apply_damage(stateOld,stateNew,k,nblock,nstatev,
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* rrandnum,charlength,props,nprops,dt,iactive,steptime,
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* totaltime)
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c
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include 'vaba_param.inc'
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c
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dimension stateNew(nblock,nstatev),charlength(nblock)
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dimension props(nprops),stateOld(nblock,nstatev)
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c -------------------------------------------------------------------
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c Taken from values stored in common blocks in VUMAT
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dimension iactive(400000)
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dimension rrandnum(400000)
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c -------------------------------------------------------------------
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c Determine Characteristic Element Length
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e_length=charlength(k)
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c -------------------------------------------------------------------
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c Recover value of damage parameter
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if(stateOld(k,21)>0.)then
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damage=stateOld(k,21)
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else
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damage=0.
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endif
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c -------------------------------------------------------------------
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c Check if element is on exposed surface.
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do i=1,6
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icycle=0
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c
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c If any surrounding elements have been deleted in the
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c previous inc, the number of exposed faces (SDV9) increases.
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if(iactive(stateNew(k,i))==1.)then
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do j=1,6
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c Previously deleted element numbers are
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c stored in SDV 22-28.
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if(stateNew(k,i)==stateNew(k,22+j))then
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icycle=1
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endif
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enddo
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if(icycle==1)then
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cycle
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endif
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stateNew(k,9)=stateNew(k,9)+1.
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stateNew(k,22+i)=stateNew(k,i)
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c
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c Current element assumes random number of deleted
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c neighbouring element.
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if(rrandnum(stateNew(k,i))>=stateNew(k,30))then
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stateNew(k,30)=rrandnum(stateNew(k,i))*0.85
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endif
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endif
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enddo
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c -------------------------------------------------------------------
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c Recover Corrosion Parameters
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ukinetic=props(6)
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stateNew(k,29)=ukinetic
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rand_num=stateNew(k,30)
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if((statenew(k,9)>0.99))then
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if(totaltime<3.)then
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dam_inc=(ukinetic/E_LENGTH)*dt
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damage=damage+dam_inc
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endif
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endif
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statenew(k,21)=damage
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c -------------------------------------------------------------------
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c Remove Fully Damaged Elements
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if(statenew(k,18)>0.1515)then
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damage=1.d0
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endif
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if(damage>=0.999)then
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statenew(k,20)=0.
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statenew(k,21)=1.
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iactive(statenew(k,8))=1.d0
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rrandnum(statenew(k,8))=statenew(k,30)
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endif
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c
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return
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end subroutine apply_damage
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c -------------------------------------------------------------------
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