Search
Close this search box.
Notifications
Clear all

Implementing Tangent stiffness for Ogden Model in UMAT

1 Posts
1 Users
0 Reactions
602 Views
Posts: 2
Topic starter
(@Thomas M. Moore)
New Member
Joined: 8 years ago

Hello,

I have derived the stress and Tangent stiffness expressions for Ogden material law. The derived expressions comprises of Eigen projections in tensorial notation that are obtained while differentiating eigenvalues (principal stretches). e.g. Stress S = f(lambda) N1(*)N1 + ..N2(*)N2... Tangent Stiffness C = g(lambda) N1(*)N1(*)N1(*)N1 + ... N1(*)N1(*)N2(*)N2 and so on.

I am facing difficulty while writing these expressions in UMAT. Is there any other way to get the expressions in some form other than in eigen projections one? Also how to implement tangent C as described in above example?

Topic Tags
Share: