Simulation Mechanical and Multiphysics

Reply
Active Member
ChaliBiky
Posts: 6
Registered: ‎11-24-2011
Accepted Solution

MAKE-FEM bug?

202 Views, 3 Replies
04-17-2012 11:33 PM

simulation multiphisics2012

I'm checking a pressured membrane.

 

The attached figure B shows an analysis result of a pressured dome-shaped membrane, which

is derived from figure A using Make FEM command.

Looking B, you'll notice the orientation of some meshed segments are reversed: some

pressure arrows direct wrong.

 

Is this a bug of MAKE-FEM? How can I fix this problem by manual? how to reverse some arrows?

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

Re: MAKE-FEM bug?

04-20-2012 11:08 AM in reply to: ChaliBiky

Hi Chalibiky,

 

It is difficult to know where the problem lies without having the model. The items I suggest checking in model B are the surface number of the lines and the location of the element normal coordinate. These can be checked in the FEA Editor from the "View > Appearance > Color By > Surface" and the part's Element Definition, respectively.

 

The Make FEM command ("Results Options > Other > Tools > Make FEM") needs to make assumptions or use default values for some of the input, so I think you simply need to update that information to make the new model correct.

 

 

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
ChaliBiky
Posts: 6
Registered: ‎11-24-2011

Re: MAKE-FEM bug?

04-21-2012 10:55 PM in reply to: INACTIVE_AstroJohn

Thank you for your reply.

 By the way I modeled A with 4 points structured mesh,using divisions number=4 for both sides.

 According to your suggestion, I selected Model B and changed surface number = 2 , but nothing has

changed.

 

Now I traced model B facets with 4 points structred mesh with divisions number=1 for both sides

one by one each clockwisely, making model C. This is very time consuming but no way due to your

bugs. Selecting model C all and add pressure and run to see the same wrong results.

could you explain this?

 

Regards,

 ChaliBiky

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

Re: MAKE-FEM bug?

04-23-2012 08:12 AM in reply to: ChaliBiky

User error. :smileyindifferent:

 

Under the Element Definition, on the Orientation tab, you need to enter the Element Normal coordinate so that it is a point "underneath" the structure. For example, (0, 0, -500) mm.

 

To understand why the input was incorrect, click the Help button on the Element Definition dialog, then scroll down the page to the section "Control Orientation Membrane Elements > Element Axes". Essentially, each individual element is like a sheet of paper. You applied a pressure to the paper, but where did you tell the software which side of the paper you wanted the pressure? That is what the Element Normal coordinate is for.

 

 

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.