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clinton.brown
Posts: 1
Registered: ‎10-23-2012

How to view curvature of surface/elements for modal analysis?

120 Views, 3 Replies
11-26-2013 06:54 AM

 

Hi,

I've got a really simple midplane meshed flat plastic sheet. I'm looking to use the modal analysis results to add some stiffening ribs, but I want to be a bit smarter and add the ribs in the area of highest curvature according to each result. I know I can view the rotational displacement magnitude in the results tab, but is there a way of viewing the element or surface curvature instead?

 

If I was to export the results as an FBX I could somehow get it into Inventor (perhaps via 3DS Max) and use the Inventor surface analysis tools but there must be an easy way of doing this in Sim Mech?


Many thanks in advance for your help

Luke

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Contributor
LukeDavenport
Posts: 27
Registered: ‎02-02-2012

Re: How to view curvature of surface/elements for modal analysis?

11-27-2013 06:48 AM in reply to: clinton.brown

Hi,

Can an Autodesk employee or mentor just give me a simple yes/no for this? Is it possible to display curvature of surfaces or not?

 

Many thanks

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Valued Mentor
AstroJohnPE
Posts: 503
Registered: ‎08-30-2012

Re: How to view curvature of surface/elements for modal analysis?

11-27-2013 10:10 AM in reply to: LukeDavenport

The software does not plot the curvature.

 

I have not run a modal analysis for awhile, but I think that such an analysis now outputs normalized stress (or some type of "stress" based on the mode shape). If this is the case, then it probably also calculates the moment within the plate elements. The moment is proportional to the curvature by 1/rho = Moment/(E*I) where either rho or 1/rho is the curvature, but I do not remember which one. (This equation is given in text books when dealing with the topic of beam deflections by integration.) The plate bending result is probably under "Results Contours > Other Results > Plate something".)

 

If 1/rho is the curvature, then plotting the bending moment will show where the maximum curvature occurs (where the moment is the greatest). If rho is the curvature, then you want to plot 1/moment which can be done by writing a custom equation within the software.

 

 

John Holtz, PE
Mechanical Engineer
Pittsburgh, PA

16 years experience with Simulation Mechanical
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Contributor
LukeDavenport
Posts: 27
Registered: ‎02-02-2012

Re: How to view curvature of surface/elements for modal analysis?

11-27-2013 11:17 PM in reply to: AstroJohnPE
Wow. Thanks AstroJohnPE for your input on this. That definitely gives me
something to work with.
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