Hill VUMat 子程序（

     subroutine vumat(

C Read only -

     1 nblock, ndir, nshr, nstatev, nfieldv, nprops, lanneal,

     2 stepTime, totalTime, dt, cmname, coordMp, charLength,

     3 props, density, strainInc, relSpinInc,

     4 tempOld, stretchOld, defgradOld, fieldOld,

     3 stressOld, stateOld, enerInternOld, enerInelasOld,

     6 tempNew, stretchNew, defgradNew, fieldNew,

C Write only -

     5 stressNew, stateNew, enerInternNew, enerInelasNew )

C

      include  'vaba_param.inc'

C     

C All arrays dimensioned by (*) are not used in this algorithm

      dimension props(nprops), density(nblock),

     1 coordMp(nblock,*),

     2 charLength(*), strainInc(nblock,ndir+nshr),

     3 relSpinInc(*), tempOld(*),

     4 stretchOld(*), defgradOld(*),

     5 fieldOld(nblock,nfieldv), stressOld(nblock,ndir+nshr),

     6 stateOld(nblock,nstatev), enerInternOld(nblock),

     7 enerInelasOld(nblock), tempNew(*),

     8 stretchNew(*), defgradNew(*), fieldNew(*),

     9 stressNew(nblock,ndir+nshr), stateNew(nblock,nstatev),

     1 enerInternNew(nblock), enerInelasNew(nblock)

C

      character*80 cmname

C

      parameter ( zero = 0.d0, one = 1.d0, two = 2.d0,

     *     third = 1.d0 / 3.d0, half = 0.5d0, op5 = 1.5d0)

C

C For  3D cases using

C bilinear isotropic hardening.

C

C The state variable is stored as:

C

C            STATE(*,1) = equivalent plastic strain

C

C User needs to input

C     props(1)      Young’s modulus

C     props(2)      Poisson’s ratio

C     props(3..)    syield and hardening data

C     calls vuhard for curve of yield stress vs. plastic strain

C

      e      = props(1)

      xnu    = props(2)

      twomu  = e / ( one + xnu )

      alamda = xnu * twomu / ( one - two * xnu )

      thremu = op5 * twomu

      nvalue = nprops/2-1

C 定义常数

      r0=0.4910

      r45=0.5256

      r90=0.5613

      F=r0/(r90*(r0+1))

      G=1/(r0+1)

      H=r0/(r0+1)

      N=1/2*(r0+r90)*(1+2*r45)/(r90*(r0+1))

      L=N

      M=N

      TOL=0.1