hi,

could you all help me to do the dynamic analysis - eart quake

This isn't something one can explain in a Discussion Forum or an e-mail. This would take several hours (minimum) to explain if you were sitting right in front of me.

Go through the examples in the Applications Guide and the NUREG9 job in the \caesar\examples directory. Have someone in your office familiar with seismic analysis to explain the basics to you.

... and please don't double post !

Hello G'men
We are analysing compressor lines - 20" sch 140. We have adequately supported the lines, and in static analysis all the results like stresses nozzle load and displacements are perfectly ok. In fact thermal displacements at any point is less than 4 mm.
Now when we run the dynamic analysis for natural frequency check the lowest frequencies are 2.5 hz, and the clients requirement is 4 to 5 hz.
we can not add too many guides since that affects static analysis.
Just for curiosity, eventhough there isnt any vibration problem, we modelled snubbers at two to three location and surprisingly the lowest frequency reached 8 hz. please note that we didnt modelled any occasional case for snubber. Can anybody explain this behaviour of piping in dynamic analysis (frequencies are improved by snubber eventhough its not vibration problem)

Regards