Modal analysis of a beam attached to spring mass system

Can "Modal analysis of a beam attached to spring mass system" be done by nastran, ansys , abaqus...
I know nastran can solve, but as mixed elements, will there be any error in result?

 

There is always error in any model system because the model is limited by it's resolution and assumptions. The better question is "Is the computational art sufficiently advanced to conduct modal analysis of a beam attached to a spring mass system within the necessary engineering accuracy?" The answer to that is maybe, and has been for over half a century. It all depends on how fine you want to slice the apple, some things are acheivable, others are not within our ability to correctly model. See Theory of Seakeeping by Korvin-Kroukovsky, SNAME, 1961.

What exactly are you looking to solve? Maybe we could point you in the proper direction.

 

I think this is the wrong forum for this kind of questions. You have more probabilities to find the answer on forums dedicated to FEM software - like the this one, for example:

http://www.eng-tips.com/threadminder.cfm?pid=727

Cheers

 

The short answer is yes. Any reputable fea program will give you correct theoretical results based on the inputs you give it. You can mix element types.

 

As with any FEA, if you're unsure, find a text book. Find one that shows how to solve, manually, what it is your after, in basic simple form.

Then rerun the same model/analysis from the text book in your FE software and compare the reuslts. That should give you an indication of the %'age error in a known and fixed result.