Moment of inertia

[amitloginsites]

Hello all,

How do i add Area moment of inertia in the query through measured bodies? It only gives me Mass moment of inertia.

Thanks

 

[JohnRBaker]

You can get Area Moments of Inertia using either...

Analysis -> Section Inertia...

...or...

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

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

http://www.siemens.com/plm

UG/NX Museum:

http://www.plmworld.org/p/cm/ld/fid=209

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

 

[amitloginsites]

Thanks John! I am still struggling with it. There are so many options which i do not understand (Very new to NX). First it give ask me to select boundary, face. I select boundary then face - XC-YC option but it does not give any answer. Can you please walk me through the steps? I really appreciate it.

 

[JohnRBaker]

First off, the 'Area using Curves' function is very old and while it still works, the UI is all but obsolete. The 'Section Inertia' is more modern and would be where I would start. But if you have a very simple model and you need one a single set of results using a single area, the older function is still perfectly viable.

In either case, what you're supposed to do is use either (but NOT both at once) a profile of curves, such as a section though the model, or a face which represents the profile of the model, which can often be the end face of say an extruded model with a constant cross-section.

With the older 'Area using Curves' you can only get a single result for a single profile, but with the 'Section Inertia' function you can define a set of cross-sections if you need to see how the area properties of a model varies as you move along some axis or curve.

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

http://www.siemens.com/plm

UG/NX Museum:

http://www.plmworld.org/p/cm/ld/fid=209

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

 

[amitloginsites]

I followed the instruction above for "Section inertia" option. I still get some bogus results. Please see the attached for the steps i am following. It is a 10x10x10 block and second moment of inertia about centroid (any axis) should be 833.33.

 

[JohnRBaker]

If you will expand the 'Settings' section of the Section Inertia Analysis dialog I suspect that you will find that the 'Section Type' was set to 'Hollow'. Change it to 'Solid' and repeat the analysis. I think you'll now get the answer that you were expecting.

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

http://www.siemens.com/plm

UG/NX Museum:

http://www.plmworld.org/p/cm/ld/fid=209

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

 

[cowski]

Also choose the opposite face to the one you have selected and the top and bottom faces (4 total); imagine a datum plane cutting through your cube and pick the faces it needs to intersect with to outline your 'section'. In the 'settings' section of the dialog box, make sure it is set to 'solid'. Since only 1 face was selected (as shown) it defaulted to a 'hollow' analysis, using a specified (or default) hollow distance.

 

[amitloginsites]

Finally i got it. Thanks a lot John!