FEAP User Forum

FEAP => Input File Issues => Topic started by: zhouzhoukth on April 22, 2016, 07:59:07 AM

Title: convergence problem with Saint Venant-kirchhoff model
Post by: zhouzhoukth on April 22, 2016, 07:59:07 AM

hey Guys,
This my first Material Constitutive Model, it's Saint Venant-Kirchhoff Material.
However, there is problems with the convergence
I upload the material code written by myself and the outfile!
it would be so appreciated if anyone could give me some suggestion!

Title: Re: convergence problem with Saint Venant-kirchhoff model
Post by: Yaakov on April 22, 2016, 01:01:37 PM

look at the material model from Prof. Govindjee.

links:
http://www.ce.berkeley.edu/~sanjay/FEAP/cubic.html

maybe you can get new idea about coding in feap for this typ problem.

the other way is, look material model in feap resource code dokument, like linear viscoelasticity, hyperelasticity ....

Title: Re: convergence problem with Saint Venant-kirchhoff model
Post by: zhouzhoukth on May 04, 2016, 02:47:17 AM

i think i had error in the push forward operation, but still no clue where is the error.

Title: Re: convergence problem with Saint Venant-kirchhoff model
Post by: zhouzhoukth on May 04, 2016, 02:47:42 AM

      Cspat=0.0d0
       Do i=1,3
          Do j=1,3
              Do k=1,3
                 Do l=1,3
                     Do tt=1,3
                        Do bb=1,3
                           Do cc=1,3
                             Do mm=1,3 
           Cspat(Elamn(i,j),Elamn(k,l))=Cspat(Elamn(i,j),Elamn(k,l)) +
     *   F(i,tt)*F(j,bb)*Cmat(Elamn(tt,bb),Elamn(cc,mm))*
     *     F(k,cc)*F(l,mm)
                             End do
                           End do
                       End do
                     End do
                 End do
               End do
           End do
         End do