Moment of Inertia of Rounded Hollow Rectangle
Moment of Inertia of Rounded Hollow Rectangle
(OP)
Hello,
I can't seem to find how to calculate the second moment of inertia (Ixx and Iyy) of a rectangle WITH rounded corners.
The below link is great for hollow rectangles, but does anyone know how to calculate it if the corners have radii?
http://www.amesweb.info/SectionalPropertiesTabs/Se...
I can't seem to find how to calculate the second moment of inertia (Ixx and Iyy) of a rectangle WITH rounded corners.
The below link is great for hollow rectangles, but does anyone know how to calculate it if the corners have radii?
http://www.amesweb.info/SectionalPropertiesTabs/Se...





RE: Moment of Inertia of Rounded Hollow Rectangle
Get out your strength of materials textbook. Calculate the centroid and MOI of each segment about its own centroid. Then calculate the centroid and MOI of the composite shape per the parallel axis theorem.
Or, if it is a standard shape, you may be able to just look it up.
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Moment of Inertia of Rounded Hollow Rectangle
Also note that tabulated values may not show the same section properties that you'd get using tabulated radii. I think on beams, they use the largest radius for clearance reasons and the smaller radius or some average radius for area properties, etc., so they don't always correspond.
RE: Moment of Inertia of Rounded Hollow Rectangle
RE: Moment of Inertia of Rounded Hollow Rectangle
https://newtonexcelbach.wordpress.com/2015/07/08/s...
It is from "our own" ids
http://www.eng-tips.com/userinfo.cfm?member=IDS
=====================================
(2B)+(2B)' ?
RE: Moment of Inertia of Rounded Hollow Rectangle
another day in paradise, or is paradise one day closer ?
RE: Moment of Inertia of Rounded Hollow Rectangle
I've done enough parallel axis theorem calculations over the years to know the approach, and yes it could be done this way, but it would be slow and painful.
RE: Moment of Inertia of Rounded Hollow Rectangle
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Moment of Inertia of Rounded Hollow Rectangle
See sample spreadsheet attached. I have split the section into two vertical rectangles, two horizontal rectangles and two semi-annuli for the corners. The section properties for the semi-annulus come from my spreadsheet previously linked by Pete (https://newtonexcelbach.wordpress.com/2014/11/02/s...).
As always, please assume that both spreadsheets give incorrect results, until proved otherwise.
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: Moment of Inertia of Rounded Hollow Rectangle
another day in paradise, or is paradise one day closer ?
RE: Moment of Inertia of Rounded Hollow Rectangle