umat_small_strain.for File Reference

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Functions/Subroutines
subroutine	umat (stress, statev, ddsdde, sse, spd, scd, rpl, ddsddt, drplde, drpldt, stran, dstran, time, dtime, temp, dtemp, predef, dpred, cmname, ndi, nshr, ntens, nstatv, props, nprops, coords, drot, pnewdt, celent, dfgrd0, dfgrd1, noel, npt, layer, kspt, kstep, kinc)

Function/Subroutine Documentation

umat()

subroutine umat	(	dimension(ntens)	stress,
		dimension(nstatv)	statev,
		dimension(ntens,ntens)	ddsdde,
			sse,
			spd,
			scd,
			rpl,
		dimension(ntens)	ddsddt,
		dimension(ntens)	drplde,
			drpldt,
		dimension(ntens)	stran,
		dimension(ntens)	dstran,
		dimension(2)	time,
			dtime,
			temp,
			dtemp,
		dimension(1)	predef,
		dimension(1)	dpred,
		character*80	cmname,
			ndi,
			nshr,
			ntens,
			nstatv,
		dimension(nprops)	props,
			nprops,
		dimension(3)	coords,
		dimension(3,3)	drot,
			pnewdt,
			celent,
		dimension(3,3)	dfgrd0,
		dimension(3,3)	dfgrd1,
			noel,
			npt,
			layer,
			kspt,
			kstep,
			kinc
	)

Definition at line 8 of file umat_small_strain.for.

 
      implicit real*8(a-h,o-z)
 
      dimension stress(ntens),statev(nstatv),
     + ddsdde(ntens,ntens),ddsddt(ntens),drplde(ntens),
     + stran(ntens),dstran(ntens),time(2),predef(1),dpred(1),
     + props(nprops),coords(3),drot(3,3),dfgrd0(3,3),dfgrd1(3,3)
 
      character*80 cmname
 
      integer i,j
 
      real*8 eye(3,3),eps(3,3),sigma(3,3)
      real*8 young,nu,mu,kappa,lambda,treps
 
 
      real*8 zero,one,two,half,three,third
      parameter(zero=0.d0,one=1.d0,two=2.d0,half=0.5d0,three=3.d0,
     +     third=1.d0/3.d0)
 
      eye = zero
      do i=1,3
         eye(i,i) = one
      enddo
 
      young = props(1)
      nu = props(2)
      mu = young/(two*(one+nu))
      kappa = young/(three*(one-two*nu))
      lambda = kappa - two*third*mu
 
      eps = half*(dfgrd1 + transpose(dfgrd1)) - eye
      treps = eps(1,1) + eps(2,2) + eps(3,3)
      sigma = two*mu*eps + lambda*treps*eye
 
      stress(1) = sigma(1,1)
      stress(2) = sigma(2,2)
      stress(3) = sigma(3,3)
      stress(4) = sigma(1,2)
      if(ntens.eq.6) then
         stress(5) = sigma(1,3)
         stress(6) = sigma(2,3)
      endif
 
      ddsdde = zero
 
      do i=1,3
         ddsdde(i,i) = lambda + two*mu
      enddo
      do i=1,3
         do j=1,3
            if(i.ne.j) ddsdde(i,j) = lambda
         enddo
      enddo
      do i=4,ntens
         ddsdde(i,i) = mu
      enddo
 
      return