09-26-2010, 07:14 PM
Hi ,
I can Help you to get natural frequency by using Sap
follow the following steps
1- draw the model as a shell elemnts ( this is more accute rather than to draw as frame elemnts)
2- Run analysis
Sap automatically will generate the modal analysis
(modal analysis = dynamic analysis method to get the natural frequencies)
then you will get the first natural frequency then second then third
and so and so
usually we will be interested to get the first natural frequency in x direction
and first natural frequency in y direction
and because the cheminy is symmetric so you will get firsnatural freq in x-dir same as first natural frequency in y dirction.
from this analysis you will get time period of first mode T
this value is very important to get the seismic force
Hoping this will be useful for you
I can Help you to get natural frequency by using Sap
follow the following steps
1- draw the model as a shell elemnts ( this is more accute rather than to draw as frame elemnts)
2- Run analysis
Sap automatically will generate the modal analysis
(modal analysis = dynamic analysis method to get the natural frequencies)
then you will get the first natural frequency then second then third
and so and so
usually we will be interested to get the first natural frequency in x direction
and first natural frequency in y direction
and because the cheminy is symmetric so you will get firsnatural freq in x-dir same as first natural frequency in y dirction.
from this analysis you will get time period of first mode T
this value is very important to get the seismic force
Hoping this will be useful for you