Simulation Mechanical and Multiphysics

Reply
Active Member
JLK64
Posts: 7
Registered: ‎12-13-2010

Plate Vs Brick

207 Views, 2 Replies
10-17-2011 08:48 AM

While performing a modal analysis on a sheet metal assembly, the model was meshed with plate elements.  A second analysis was performed with the same geometry,but with brick elements.  The results between the plate elements and brick elements is quite different.  Can someone give me an idea why this would be?

Please use plain text.
Employee
INACTIVE_AstroJohn
Posts: 492
Registered: ‎03-25-2010

Re: Plate Vs Brick

10-17-2011 09:08 AM in reply to: JLK64

Hi,

 

I am going to take a guess that the frequencies from the brick model were higher. That can be explained by the stiffness of brick elements in a bending mode. Brick models with bending usually need more than one element through the thickness to accurately capture the bending. (You may be able to compensate for that issue if you include the midside nodes for the brick parts. That setting is under the Element Definition.)

 

If the plate model has higher frequencies, then something is wrong in the setup. Either the weight of the models is different, or the boundary conditions are different.

 

Sincerely,
John Holtz, P.E.
Senior User Experience Designer, Simulation
Autodesk, Inc.

Current version of Mechanical & Multiphysics: 2013 SP1 (2013.01.00.0012 28-Jun-2012)
Please use plain text.
Active Member
JLK64
Posts: 7
Registered: ‎12-13-2010

Re: Plate Vs Brick

10-17-2011 09:23 AM in reply to: INACTIVE_AstroJohn

You're correct - the brick model did have higher frequencies.  I'll revise the mesh number of elements through the thickness.  Thanks for your help!

Please use plain text.