Composite materials in compression

Hi there,

hope you are having a nice and sweet day.

I am wondering if anybody in the community has faced the problem I am at the moment.

I am modelling a fiber reinforced plastic using REINF elements in ANSYS (which I believe are equivalent to REBAR elements in MARC or ABAQUS).

The fibers are modelled as a membrane with unidirectional stiffness in the fiber direction.

the problem is that in the as built ANSYS element the fiber has the same stiffness in compression and tension, which is not relastic because the fibers will buckle depending on their bending stiffness and the matrix properties.

How can this be overcome without resorting to an User defined material?

If a USERMAT is the only option, is it possible to define a 1 - D material model?

Thank you all

Best Regards

Muzialis

I have heard that question before, and I cannot think of a easy way to solve the problem without resorting to a user-material.

Abaqus can handle 1-D user-materials, I dont recall if Ansys supports that...

-Jorgen