Moment of Inertia for an "L" shape
Moment of Inertia for an "L" shape
(OP)
Hello,
Does anyone out there know if there's an equation to find the moment of inertia for an "L" shape without having to do the moment area method?
Does anyone out there know if there's an equation to find the moment of inertia for an "L" shape without having to do the moment area method?






RE: Moment of Inertia for an "L" shape
RE: Moment of Inertia for an "L" shape
Dicsewerrat,
No. The steel book does not specifically show you how to find Ix and Iy. I need to know if someone knows of a specific reference that would show me how to write and equation.
RE: Moment of Inertia for an "L" shape
RE: Moment of Inertia for an "L" shape
it has a module that could calculate shape properties.
Or you could check out some mechanics of solid books.
Hope this helps.
RE: Moment of Inertia for an "L" shape
Now if it's an angle and not an "L", you'll have to break it up into a bunch of paraboloids and trapazoids. I near-mastered this (OK, they're really thin lines sections) when teaching myself light gauge steel design (yow! That is a pain!)
You may want to look at Blodgett's book "Design of Weldments" for more insight into this problem.
Anyway, the parallel-axis theorem is easy and kind of fun, too. Taking moments of areas is really easy, especially if they're two rectangles. I normally refer to the "moment area" method as a tool for computering beam deflections.
RE: Moment of Inertia for an "L" shape
Iyy.
RE: Moment of Inertia for an "L" shape
Ed
RE: Moment of Inertia for an "L" shape
Thank you for your respond. I don't think you can use the parallel axis theorem to calculate Ix and Iy for an "L" shape. There's no symmetry for an "L". Am I correct?
RE: Moment of Inertia for an "L" shape
How do you go about getting the uu and vv axis? I am trying to get the Ix and Iy for the critical buckling of a built-up "L" shape wood column.
RE: Moment of Inertia for an "L" shape
http://www.efunda.com/math/areas/RectangularLBeam.cfm
Why are you making this easy probelm so hard for yourself?
RE: Moment of Inertia for an "L" shape
Are you some kind of a super raging genius? Thank you very much. That is what I am looking for.
Also, thank you to the following people for their responds:
Dicksewerrat, IFRs, Lutein, and kags.
A special thank you to Edbell for his awesome spread sheet.
It's great to have fellow engineers help each other.
Sincerely,
workhorse