CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > ANSYS

Eigenfrequencies static and modal analysis

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   May 12, 2012, 18:25
Lightbulb Eigenfrequencies static and modal analysis
  #1
New Member
 
Join Date: May 2012
Posts: 2
Rep Power: 0
Laura_mecheng is on a distinguished road
Hello,

I am doing an ANSYS analysis and now I don't understand something. The construction I am analyzing is a goal (like from soccer) and in the middle a force of 1000 N is applied. First I did a static analysis and calculated the natural frequency with √ (k/m)/(2∏).
Where k is the stiffness and described by F/δ_middle so δ_middle is defined where the force is applied and therefore the maximum deflection.

After that I did a modal analysis and calculated the first 5 eigenfrequencies. The first eigenfrequency is now around two times higher as the frequency calculated with the static analysis.

Where does this difference come from? So the difference between the natural frequency calculated with the static analysis and the first eigenfrequency calculated with the modal analysis.

What is exactly the difference between the static and dynamic calculation in ANSYS? With statics it does not take mass and accelerations into account I think but I don't see how this exactly works in ANSYS.

Thanks for helping in advance .
Laura_mecheng is offline   Reply With Quote

Old   May 15, 2012, 03:40
Default
  #2
New Member
 
Join Date: May 2012
Posts: 2
Rep Power: 0
Laura_mecheng is on a distinguished road
Anyone?
Laura_mecheng is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to start modal analysis Mvaz FLUENT 10 January 16, 2006 09:40


All times are GMT -4. The time now is 18:17.