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

[clinton.brown]

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

[LukeDavenport]

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

[AstroJohnPE]

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.

[LukeDavenport]

Wow. Thanks AstroJohnPE for your input on this. That definitely gives me
something to work with.