Hi all,

Recently I was reviewing a calculation carried out by my engineer on a two phase line (Steam blow down line). This was a three inch header on rack. Modal check was done to check the natural frequency of the line. Line was modelled with the supports at every 6m as available on pipe rack. We have to add guides at every support to have a frequency above the project requirement of 8Hz.
While checking I created addinational nodes at every 3M to check frequncy in between the supports assuming that CAESAR will not check the frequency for these points. And I found that the frequncy at these intermediate nodes was less than 3 Hz. Now I have a doubt if it is ok to check the freqency just at 6m span supports or we should creat intermediate nodes. I am using Lumped mass model option.
Can anybody comment on this?