What is your objective of said analysis/modelling?. why you need reduced modelling technique?

From the figure it is understood that you are doing buckling analysis and applying compressive load on the end plate. You are also supplying stress-strain curve to the analysis i.e. doing material nL analysis.

Hi Inaam Qazi,

Successful modelling of the problem you propose is largely dependent on some additional details.

It is not clear are the tubes made of the same material or different ones. If the material of the tubes is the same then we must suppose that one of the presented stress-strain diagrams depicts behavior of the end plate's material.

If we consider the contact problem then we must think about conditions at contact zones.

As the first approach it is possible to model the problem as axisymmetric one. In any case we can consider 1/2 part of the system because the plane z=l/2 is the plane of symmetry.

Best wishes.

Dear Dr Victor

Two coaxial tubes, the inner one of 1020 CR steel and cross-sectional area As, and the outer one of 2024-T4 aluminum alloy and of area Aa, are compressed between heavy, flat end plates, as shown below. Determine the load-deflection curve of the assembly as it is compressed into the plastic region by an axial displacement. Assume that the end plates are so stiff that both tubes are shortened by exactly the same amount.This explains the problem in detail.

But the manner of reduction for solid and shell elements is not clear, for example why use a theta = 6 for modelling. Has it anything to do with meshing appropriateness of the model?

Dear Chitranjan

I am learning to determine non linear load deflection curve based on displacement based method.

Dear Claudio

You have been a constant help.This is vm7 from ansys help file. I am learning different modelling techniques to enhance my skill set. What I am really interested in is determining the numerical capacities of the I beam modelled with SHELL 181, where I have to use reactions from multiple node points ( I have not figured that out yet). and plot a load deflection curve. The gist is to determine non linear capacity of the section incorporating material and geometric non linearity.

Thanks

With Regards

Inaam