At 10:17 AM 10/12/99 -0500, you wrote:
>Would anyone have any information on how to implement a bilinear material
>definition in Abaqus?
>
>The only way I am aware of is through the use of a user-defined material
>(UMAT). But, I am unsure of how to code the material definition. Could
>someone who has coded something similar please offer some assistance? Or,
>if there is alternative method.
>
>The data I am working with is the value of the Young's modulus of
>elasticity corresponding to a region of strain and an additional value of
>the Young's modulus for the second region of strain through failure/maximum
>strain.
>
>Thanks in advance for any feedback
>
>Brad Probst
>Dept. of Biomedical Eng.
>Tulane University

Brad,

I see a couple of replies advising using *ELASTIC and *PLASTIC but be
careful there.   Two questions:  is your material elastic up to failure of
does it actually go plastic?   It won't matter if the loading is monotonic
everywhere.   If not, and some of it unloads, then *PLASTIC won't give the
right response.

I also see that you're in a biomedical department.   If you're working with
a nonlinear elastic biomaterial then *HYPERELASTIC may be your best bet up
to the point of failure.   If you want to allow it to damage and fail, you
may need to use UMAT.   However I find VUMAT, as found in Abaqus/Explicit,
easier to code.

Regards,

Ron.

PS I've also posted this to [log in to unmask]   There are
subscribers there who're at the interface between engineering and bio-stuff.





Dr R D Thomson
Ballistics, Impact + Sports Eng Group
Mech Eng Dept, Glasgow Uni
Glasgow G12 8QQ, Scotland

tel UK (44) Gla (141) 330 4313
fax UK (44) Gla (141) 330 4343
web http://www.mech.gla.ac.uk/~rthomson

ISEA website:
    http://www.sports-engineering.co.uk/


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%