SAMICORP's blog

Hello, 

I was wondering how is it possible to implement incompressible neohookean material in abaqus? 

With the incompressibility assumption c(3,3)=1/(- c(1,2)^2 + c11*c22), with c being the Cauchy-Green strain tensor. It also implies that S33=0 and it is possible to find the pressure directly. In addition, h=sqrt(c(3,3))*h0 with h and h0 being current and initial thickness, respectively. 

my question is that how is it possible to implement the last condition in umat? 

i am still struggling with  defining an initial condition in vumat. i have defined mine like this:

STATEV(1:nstatev)=stateOld(KM,1:nstatev) 

          if (steptime .eq. zero) then

          STATEV(1) = 1.0d0

            STATEV(2) = 1.0d0

            STATEV(3) = 1.0d0

            STATEV(4) = 0.0d0

            STATEV(5) = 0.0d0

            STATEV(6) = 0.0d0

            STATEV(7) = 0.0d0

            end if

      BBAR_DE_N(1,1)= STATEV(1)

      BBAR_DE_N(2,2)= STATEV(2)

      BBAR_DE_N(3,3)= STATEV(3)