NEO HOOKEAN

[dmeloni]

prof. Bergstrom,
I downloaded your VUMAT for the Neo Hookean material model in Abaqus explicit. I'm practicing with it and I compared the above with built-in material model Neo Hookean on the same simple model. while the latter worked well till the final time step, the job with the Vumat exited with an error related to excessive distortion of elements; it seems that the model became unstable.
is there anything I should know about that subroutine? did you test it? should I have to add some instructions? why you didn't provide the instruction:
include Vaba_param.inc
as it is suggested in the manuals.
thanks for your attention
DANIEL MELONI

[Jorgen]

Hi Daniel,

There is a lot of discussion about the short demonstration VUMAT that I wrote in the following thread (http://www.polymerfem.com/modules.php?name=Forums&file=viewtopic&t=9).

The VUMAT should work OK the way it is written.

I did not include the "Vaba_param.inc" because of personal Fortran coding reasons. You can certainly include that file if you like to. I am personally strongly agains implicitly defining any variables when writing code. I think that is a bad and dangerous practice.

- Jorgen