# Moment of inertia - curved flat bar

1. Mar 14, 2012

### Bearcat_w

I am trying to calculate the moment of inertia of a formed (uniform curve) flat bar. I have attached a sketch . The bar is 5/8" thick x 1" wide. I'm stumped.

#### Attached Files:

• ###### Curved plate.jpg
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2. Mar 14, 2012

### Mech_Engineer

Is this a homework problem where you need to come up with the derivation?

Roark's Formulas for Stress and Strain has the answer to that exact section, in Appendix A, Table A.1 (Properties of Sections).

3. Mar 15, 2012

### Bearcat_w

Thanks for the fast reply. Exactly what I needed. My 5th Edition Roark lacks the appendix!

4. Mar 15, 2012

### Mech_Engineer

I have the Seventh edition and it has it, and from what I can tell the Sixth edition has it as well. Time to get a new Roark's!

5. Mar 15, 2012

### mrajm

hi there..
i think you are trying to find the stress at a section in this problem..
is this a thick or a thin section? With some calculus we can figure out what will be the moment of inertia..

6. Mar 15, 2012

### seba102288

If your looking for an exact answer you would have integrate it using:

Ixy=∫xydA since it is curved

Honestly though I would just get a rough estimate with a simple rectangular cross-section area moment of inertia equation

I=1/12bh^3

or I would use a program like Solidworks that would calculate it for me.

If you want to know more about area moment of inertia this is a good web page that gives a basic overview

http://sbainvent.com/strength_of_materials/area-moment-of-inertia.php