Second Moment of Area About the Centroid 2D

[baudencm]

I have a 2D shape for which I want to find the centroidal moment of inertia. When I try to query the mass properties, it only shows Area and Area Centroid. Is it possible to also display the second moment about the centroidal axes for a 2D shape?

I am able to get the moments of inertia for a solid 3D shape but this is not necessarily what I want.

Thanks!

CB

 

[rstupplebeen]

It's been a while since I have used beams however I believe that if you define a section in CAE it actually just writes out the properties not the actual shape. Check out the .INP. I hope this helps.

Rob Stupplebeen

 

[corus]

If you can get the properties for a 3D shape then why not extrude your 2D shape and neglect one of the properties?


corus

 

[baudencm]

First of all thanks for the replies.

I tried extruding my shape so it would display the moments of inertia. It does work, however, changing the length of the extrusion changes my Ixx. (Assuming xy plane is the cross section and z is extrusion dimension.) Ixx and Iyy should not change based on the length in the z direction but for some reason it is.

I am not even able to validate bh^3/12 for a rectangular cross section.

Another odd thing I was experimenting with were different section definitions. Anytime I had to specify an out of plane thickness it would display all of the moments of inertia but again, Ixx and Iyy would change depending on the thickness value I specified. Hmmm...

As for the first suggestion, I think I know what you mean. I will attempt that approach this afternoon.

Again thanks!