uniaxial compression modeling

[bb]

Hello,

I am trying to find some guidance with the following.

I have some lab data (compression) and I am trying to create a model to predict the data. (basically, the data doesn't look right and I am trying to find corrections)

I've used a commercial FEM software to model my specimens and it is so different from the lab data that I thought it may be wrong and decided to used alternative ways to model the data.

How can I model uniaxial compression for layered structures to predict boundary displacements (bulging of the core)

Thank you very much

PS. I've tried classic elastic theory to model the contact boundary displacement and then the core displacement but I am using the slenderness ratio of the sample as cut-off value to go from one formula to another and that may present a problem for samples that are of intermediate lenght.

[Jorgen]

You should be able to predict the actual boundary displacements if you:
(1) accurately represent the geometry of the laboratory test specimen
(2) accurately represent the applied loads and boundary conditions (including friction)
(3) accurately represent the material that your specimen is made of.

Typically, part (3) is the hardest part. How you know that you use an accurate material model in your simulation?

- Jorgen

[bb]

Thank you very much for your answer

We do have all of those fairly well defined, including the material properties. I guess what I was trying to find out is if there is a particular theory or formulation I should use to solve the problem. An alternative method from those we've already used.