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Hi everyone,
My question: is that true if i assign the nodal mass resulting from the eigenvalue anaysis as a nodal mass in my dynamic analysis model since i distribute the mass along the beam-column element in the eigenvalue model
Best,
Thaer,

I have difficulty in interpreting your question, thaer.f.zy. But I'll try. I am wondering why you would want to use a different mass assignment scheme in the dynamic analysis than you use in the eigenvalue analysis. I am uncertain which 'nodal mass resulting from the eigenvalue analysis' you reference. Are these the 'effective modal (not nodal) masses' reported in eigenvalue results? If so, then it is difficult to see how those could be applied as nodal masses to your structure. Perhaps you might clarify a bit more and elaborate on the reason for wanting to use a different mass assignment scheme in the dynamic analysis than you used in the eigenvalue analysis. I think that would help in getting the question resolved. Best of luck, thaer.f.zy.

hi Tim;
thank you so much for your valuable note.
i was thinking about reducing the time and effort of the dynamic analysis by assigning the mass at nodes, so instead of recalculating the nodal mass i thought maybe i could use of the "nodal masses" in the "modal/mass quantities" as the attached photo:

https://drive.google.com/open?id=0BzZ5t ... kVwTHNQVzQ

best;
Thaer;

Ok, thaer.f.zy. I see what you are doing now. I believe that you could do as you say, enter these nodal masses in the pre-processor. You would have to subsequently zero-out material densities to prevent them from being counted twice. And you would have to enter each nodal mass as a separate input. I believe you would be better served by leaving the mass distribution to the software. I don't think that entering the masses as you propose would buy you much advantage in the dynamic analysis. If you did undertake such an endeavor, the first step would be to re-run the eigenvalue analysis and ensure that the periods and participation were identical. For myself, I would try to run the dynamic analysis with the same model as your original eigenvalue model. Let us know if you have significant findings, thaer.f.zy. Best of luck with your work.

dear Tim;
many thanks for the help and inspiring us with you notes
best;
Thaer;