Modal analysis is a nice, quick and dirty way to check if the model is ok. To attach a nodal mass element did you try using MPC beam connection between the reference node and the free point mass, i think that should solve the problem.
hi ktaze,
I assume that you are running a linear buckling analysis. It will not consider contacts in the process of doing that, since it extracts eigen values pretty much like a Modal analysis.
If you need contacts in the analysis, you might want to look at Static Riks method. It can be used...
