Solution of Frequency and Mode of Free Vibration

[WANGJIANHUI]

Dear FEAP Users，
     I want to solve the free vibration problem of three-dimensional structures.
     How to customize the number of eigenvalues obtained by solving?
     How to customize tolerance？
     I would be very grateful if you could answer it!
     Thanks for your support.

[Prof. S. Govindjee]

If you do something like

Code: [Select]

mass
tang
subs,,5

or (if you have build the optional ARPACK module)

Code: [Select]

mass
tang
arpa,,5

FEAP will compute (at least) the first 5 modes for you.  Change 5 to whatever you want.

[WANGJIANHUI]

Thank you for your reply. What should I do if I want to solve the 100 order eigenvalue

[Prof. S. Govindjee]

To solve for the first 100 eigenvalues you can use SUBS,,100 or ARPA,,100;  ARPA is only available if you built FEAP with this extra package.