Calculate Center of Mass based on components instead of solid bodies

[fosman85]

First off, i'd like to say that this forum has been very helpful with a good deal of the minor NX questions i've had, and for that i'm pretty grateful.

Now on to the question at hand:
I'm in the unique possition of needing a way to calculate centers of mass in NX based on componenet weight. This is essentially due to the fact that altreps have been used (and begrudgingly at that), which in my understanding pretty much eliminates the ability to get and accurate center of mass based on solid bodies.

Is there a way to calculate center of mass based on known mass and centroids of the components in an assembly? There are approxiamtely 60 parts per assembly, and nearly 100 assemblies/configurations, so making an excel spreadsheet for doing this by hand is far from desirable. Running NX 7.5, by the way.

 

[cowski]

Why would altreps ruin the COG calculation?
If done correctly, they should increase your accuracy.

www.nxjournaling.com

 

[JohnRBaker]

There is a capability called Weight Management which will help you set up NX so that it uses the Mass values of the bodies found in Reference Sets (generally the 'Model' Reference Set) other than the ones that you are actually building your Assembly with. This way you can use a simplified body yet still have the system compute the Mass and Centroid using the precise models found in the 'Model' Reference Set. Weight Management will also allow you to 'assert' specific Mass values to things like simplified versions of purchased items where you know the weight from a catalogue or spec sheet.

You can find this at...

Analysis -> Advanced Mass Properties -> Advanced Weight Management...

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
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