non-linear viscoelacity

[paolo2010]

Hello everyone,

I find myself having to make a pattern to the finite elements of a non-linear viscoelastic material. in literature the constitutive equations that can describe their behavior are those theorized by fung (almost linear viscoelastic theory).

geometry is quite simple and I should simulate:
1) a uniaxial traction test
2) a stress relaxation test

I am not very expert on finite element analysis for this I ask your advice on the feasibility of 2 models

thanks to anyone who responds

 

[stefano.garbin]

very interesting problem!
first read well the guide of ansys mechanicsl apdl -> material reference -> material models (chapter 3) -> viscoelastic material model (cap 3.6) and see if your material model can somehow fall into the description.
if so it wasn't afraid that you will have to write a routine with the equations characteristics of the material (a usermat), but it is a thing that you do with programming in fortran and compilation of ansys executable "custom"... and here I can't help you unfortunately.
then for geometries and load conditions do not worry that it comes out doing some exercises of those indicated in the "useful links" of the ansys section of this forum.

nb: it is also nice to present yourself before posting immediately the problem on the forum...

 

[paolo2010]

Thanks for the answer, I'm sorry if I was introduced

I'm a bioengineer and I'm doing my doctorate in automatic,robotic and bioengineering

I'm not very practical with ansys and finite element analysis in general...if anyone can recommend books and materials to be able to download from the installments I would be very grateful. . .

the problem I have to describe is complex even if the test in itself is nothing special. ...I would like to understand how to tell ansys that my material respects nonlinear viscoelastic behavior described by fung modeling

Thank you.