I'm performin a response spectrum analysis on a vertical pressure vessel supported by 3 legs subjected to seismic load for a nuclear plant. I need to define the BASE LOAD for each legs but I cannot extract the FORCE from the result database despite I having requested them in the input file...
Probably is NX Nastran bug..Someone could help me? Any tricks to overcome the problem?
Thank you in advance!!
Solved! Go to Solution.
I need to define the foundation loads at leg base: usually (simply static analysis) I extract them using a freebody - iterface load on the concerned nodes.
But when I try this after RSA no force value are available, even if I request them (balance force, equilibrium force, ext..) in NX Nastran input file..please find here enclosed .dat and the .f06 file.
Thank you in advance.
everything modelled with solid elements !!! wow !! Must be a hell of a good reason behing such modelling
not much time looking at detail but 1st Qs
For the solid model unfortunatly is a requirement of the Client (Nuclear Plat), and the Client is always a sufficient reason!! For the other questions please find the reply in the following:
Well I learnt something today as far as industry specific modelling - Glad I asked
so which software are you using to do your reps. sim. Is this equivalent to a Nastran SOL111 (I only SEMODES for the SOL)?
1. Not really . Could have attached the RBE2 for the exitation mass direcclty to all the pads. But that's a secondary point!
2. Should the seismic mass not attached to the RBE2 then ? I thought the seismis mass approach was "old school"
In example dat file I see analysis title SEMODES it is SOL 103 - it calculates only normal modes/eigenvalues. There are no force/stress results in this solution sequence.
For RSA NX Nastran vs - 11.0.2 has been used. I confirm that SEMODES provides stress results, for your reference please see Examples N°19 in FEMAP.
The problem is that the solver give me only element stress but not nodal forces...