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Moment of Inertia About a Specific Axis

Moment of Inertia About a Specific Axis

Moment of Inertia About a Specific Axis

(OP)
Hello, I'm trying to get the moment of inertia calculation for a "Z" section about the x axis.  The problem is when I run the section inertia it assumes you only want it the with the part rotated in it's strongest orientation and that's not what I need.  It inserts it's own coordinate system instead of using the WCS?

I did the hand caculations using the composite shapes transfer of axis theorum, so I know the numbers I'm getting from UG are not correct for the direction I'm loading the part.  I've attached a picture for reference.  Is there a way I can specify what coordinate system or part orientation I want the MOI shown for?

RE: Moment of Inertia About a Specific Axis

For this you need to use...

Analysis -> Advanced Mass Properties -> Area using Curves...

...where you get not only your section properties with respect to the WCS and the Centroid, but also the Principle Moments, which is what you're getting if you use the 'Section Inertia' function.   

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/

To an Engineer, the glass is twice as big as it needs to be.
 

RE: Moment of Inertia About a Specific Axis

(OP)
Thanks John!  I tried going thru this command prompt and did get a result...Although I don't exactly know what I'm reading in the output field.  I've attached a picture.  

My math says the MOI should be very close to .2249 in^4.  

Wasn't sure wether or not to use the boundary or face and the temp or permanent options in the beginning either.  I'm a UG novice, although I've used it for the last 10 years, I've always had the help of wonderful designers.  Thanks

Bryan
 

RE: Moment of Inertia About a Specific Axis

You would probably be better off using the 'List All' option.

As for the boundary issue of 'Permanent' versus 'Temporary', this basically an obsolete concepts so it doesn't really mean much any more.

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/

To an Engineer, the glass is twice as big as it needs to be.
 

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