I-deas normal mode system modelling

Hello All

I´m quite beginner in fem applications. Is it possible to evaluate normal mode frequencies of system which contains few parts? Lancos (sparse)solver seems to ignore all geometric elements like springs and rigid bars. This system I have need to be tuned to 100Hz resonance frequency.

Does anyone knows any good reference material for this problem? Is it possible to solve with I-deas?

Br - jesse

 

[brad]

I'm not quite clear what the source of the problem is. I can state this much--the Lanczos eigenvalue extraction should be taking into account all stiffness members in the system (springs, etc.). The 'natural frequency' of a rigid bar will be infinity (hence my use of 'natural frequency' in quotes, as it really isn't).
It is possible to evaluate natural frequency of a system with few parts--why do you believe that this is not happening? It may be that the frequency which involves deflection of the springs is higher or lower than your search area within Lanczos.
Let me know what leads you to believe that the springs are not being accounted for.
Brad