×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

mode shape

mode shape

mode shape

(OP)
i have 3D model for entire structure. Not an FEM model expert yet. I need to find out frequency of local area. Is there an easy way to find out which mode shape governs?  

RE: mode shape

Look at mass participations for each mode.  If mass participation is low (5% or less), you probably have a local mode.  Then, look at the mode shapes.  Amplify deflections until you see the local area that you are interested in deflecting by itself.

RE: mode shape

(OP)
I should be able to get rid of the local mode by increasing the member stiffness. Am I right?

RE: mode shape

You should be able to change the frequency of the local mode by increasing the stiffness.  It may no longer be the 1st mode...or a specific mode number as you may be able to drive the frequency out of the range of concern.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources