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


Natural Frequency Design Calculations

Natural Frequency Design Calculations

Natural Frequency Design Calculations

"I am a design engineer working on a multidisciplened project. I am trying to design a welded sheetmetal box that will contain a heat exchanger. The box is attached to a turbine that is producing a certain frequency. The turbine is used to create a gas flow through the heat exchanger. What formulas are there to predict the natural frequency of the sheetmetal box (if I coin stiffinening ribs or panels into the sheetmetal)? I can calculate the natural frequency of the flat panels but I have found no help in any further calculations or design guides.
Any help would be appreciated.
Thank you,

RE: Natural Frequency Design Calculations

First, you need to thoroughly characterize all of the forcing frequencies produced by the turbine and the fluid flow.  

The frequencies at the steady-state turbine speed are usually of greatest interest, but the start-up and shutdown frequency ramps should also be considered.

The box natural frequencies should well separated from the forcing frequencies, in order to avoid resonance.

Hand calculations are useful as a first approximation.  

You will probably need to make a finite element model of the box system, however, in order analyze the box natural frequencies and mode shapes more accurately.

A good, practical reference is:

V. Adams and A. Askenazi, Building Better Products with Finite Element Analysis, OnWord Press, Santa Fe, N.M., 1999.

Available from:


Sincerely, Tom Irvine
Email:  tomirvine@aol.com

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! Already a Member? Login


White Paper - A Guide to 3D Printing Materials
When it comes to using an FDM 3D printer effectively and efficiently, choosing the right material at the right time is essential. This 3D Printing Materials Guide will help give you and your team a basic understanding of some FDM 3D printing polymers and composites, their strengths and weaknesses, and when to use them. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close