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Contributor
mirred
Posts: 13
Registered: ‎02-12-2010

flange solid 3D and moments

456 Views, 9 Replies
03-31-2011 04:40 AM

 

Hi,
I have a flange whit two moments: bending and torque. I select a point (in the center of flange) and I put my moments (both 400000 Nmm) and ... nothing ... no stress and shift.
hmmm ... where is the problem?
Is there a easy example where I can to see how I can to apply the moment in a solid?

 

 

bye bye

mir

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Employee
S.LI
Posts: 398
Registered: ‎05-06-2010

Re: flange solid 3D and moments

03-31-2011 05:09 AM in reply to: mirred

What's the analysis type?

Please make sure that you have appropriate load multiplier (LSS) and load curve (MES).

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Contributor
mirred
Posts: 13
Registered: ‎02-12-2010

Re: flange solid 3D and moments

03-31-2011 05:24 AM in reply to: S.LI

Static stress with linear material models

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Employee
S.LI
Posts: 398
Registered: ‎05-06-2010

Re: flange solid 3D and moments

03-31-2011 05:37 AM in reply to: mirred

After going through your model, I know the problem: your moment load is not applied correctly.

 

Moment load is usually only applied on "rotational degree of freedom". Your failed because there is no rotational DOF for regular brick elements.

 

To resolve the problem here, you have two ways:

1.) apply moment as a remote load. This is for the case that the moment is on a surface

or

2.) If you only want to add the moment on a point/node, you have to manually add several beam elements around the node. Since beam elements carry on rotational DOF, you can apply moment on this node now.

 

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Employee
S.LI
Posts: 398
Registered: ‎05-06-2010

Re: flange solid 3D and moments

03-31-2011 05:46 AM in reply to: mirred

Here is the modified model according to the second way (adding beam elements).

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Contributor
mirred
Posts: 13
Registered: ‎02-12-2010

Re: flange solid 3D and moments

03-31-2011 05:49 AM in reply to: S.LI

hmmm ... I didn't do this .... Have you a little example or can you make my moments in my flange?

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Employee
S.LI
Posts: 398
Registered: ‎05-06-2010

Re: flange solid 3D and moments

03-31-2011 06:21 AM in reply to: mirred

I did attach the modified model in the message just above yours. :smileyhappy:

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Contributor
mirred
Posts: 13
Registered: ‎02-12-2010

Re: flange solid 3D and moments

03-31-2011 06:25 AM in reply to: S.LI

o yes .... magic!

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New Member
chrismach
Posts: 1
Registered: ‎05-03-2011

Re: flange solid 3D and moments

05-03-2011 07:19 PM in reply to: S.LI

I have a similar problem with a flange analysis.  I have an Instrumentation Flange with multiple ports in the center of the flange.  I have fixed the outer bolt holes and applied a pressure on the opposite side of the flange on the center panel where the ports are.   When the Instrumentation ports are in a circle around the edge of the center panel the analysis runs and gives reasonable results.  I go to analyze a second configuration that differs only by having 8 Inst. ports in a circle and one in the center instead of 9 Inst. ports in a full circle around a solid center and the results are zero, no stress, no displacement.

 

Any thoughts?

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Employee
S.LI
Posts: 398
Registered: ‎05-06-2010

Re: flange solid 3D and moments

05-04-2011 04:45 AM in reply to: mirred

The direct reason is the equation solver (AMG) didn't get an appropriate solution back.

I'm not sure why this happened.

 

The solution for your problem is to change the equation solver from "automatic" to "sparse", which locates at Analysis Parameters -> Solution ->Solution Options -> type of solver .

Untitled.png

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