Pre_stressed normal mode using sol 103
Pre_stressed normal mode using sol 103
(OP)
thread561-337439: Modal analysis of pre-stressed beam structure (NX Nastran)
Hello,
I want to use your first method with SOL103 using statsub .... when you talk about gravity load what is it? I saw that you were able to do this using FEMAP. can you send me the FEMAP program from your example?
You can also read my .bdf and tell me if a do a mistake.
Best Regards
Hello,
I want to use your first method with SOL103 using statsub .... when you talk about gravity load what is it? I saw that you were able to do this using FEMAP. can you send me the FEMAP program from your example?
You can also read my .bdf and tell me if a do a mistake.
Best Regards





RE: Pre_stressed normal mode using sol 103
In fact, pre-stiffened modal analysis is a great feature of NX NASTRAN modal (SOL103) solver, but I don't know if other "nastran flavour" solvers are allowed to do it.
Since modal analysis is essentially solving the differential equation of free-vibration, the load is not in the equation. So in SOL 103, the load is ignored. There are two method to take into account the gravity load effect, one is the use of STATSUB, the other is using nonlinear analysis (SOL106) with preload.
Here you are the procedure in the case of the gravity load: you need to specify the gravity load in a static subcase and including the STATSUB case control in the dynamic subcase will cause the differential stiffness to be computed and included in the normal mode solution (a similar procedure could be followed to include linear surface-to-surface contact in a modal analysis)
Here is an example with general load, inlcuding gravity load:
CODE -->
Best regards,
Blas.
~~~~~~~~~~~~~~~~~~~~~~
Blas Molero Hidalgo
Ingeniero Industrial
Director
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