ADINA - Eigenvalue problem

[cdana]

I am doing an linearized buckling analysis using ADINA for a column-type structure. For the same model of the structure, with the same load, I am do two analysis. In the first analysis I ask two modes and 15 modes in the second. The results are different.

My question is what is the resason of this difference?

 

[dozer]

You need to explain some more. Were modes 1 and 2 not the same in both? They should be. Beyond mode 2 you've got nothing to compare to.

Does your software allow a shift? This could be different between your two models. It's really hard to say without seeing the model.

Please post some more info and I'll try and help some more. (If I remember, my forgetter is working pretty good.)