Moment of inertia - curved flat bar

In summary, the individual is seeking assistance with calculating the moment of inertia of a formed flat bar with specific dimensions. They have been recommended to reference Roark's Formulas for Stress and Strain and use the properties of sections table in Appendix A. They also discuss using calculus or a program like Solidworks to calculate the moment of inertia, and provide a link for further information on area moment of inertia.
  • #1
Bearcat_w
2
0
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.
 

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  • #2
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
Thanks for the fast reply. Exactly what I needed. My 5th Edition Roark lacks the appendix!
 
  • #4
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
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
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
 

FAQ: Moment of inertia - curved flat bar

1. What is moment of inertia?

Moment of inertia is a physical property that measures an object's resistance to changes in rotational motion. It is also known as angular mass or rotational inertia.

2. How is moment of inertia calculated for a curved flat bar?

The moment of inertia for a curved flat bar can be calculated by using the formula I = 1/3 * m * (r^2 + h^2), where m is the mass of the bar, r is the radius of the curved section, and h is the height of the flat section.

3. What factors affect the moment of inertia of a curved flat bar?

The moment of inertia of a curved flat bar is affected by its mass, shape, and distribution of mass. A larger mass and a larger radius of curvature will result in a larger moment of inertia, while a thinner bar will have a smaller moment of inertia.

4. How does moment of inertia impact the stability of a curved flat bar?

The moment of inertia plays a crucial role in determining the stability of a curved flat bar. A larger moment of inertia means the object is more resistant to changes in rotational motion, making it more stable. This is why objects with a large moment of inertia, such as a spinning top, are difficult to tip over.

5. Can the moment of inertia of a curved flat bar be changed?

Yes, the moment of inertia of a curved flat bar can be changed by altering its shape, mass, or distribution of mass. For example, increasing the radius of curvature or adding more mass to the bar will increase its moment of inertia, while reducing the mass or making the bar thinner will decrease its moment of inertia.

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