Aluminum Angles in Bending/Flexure (Lateral Torsional Buckling)

[greauxpete]

I am trying to design an aluminum angle in bending/flexure.
The aluminum Association 2005 looks at:

1. Local buckling of leg tip in max compression (which I understand)
2. Leg in uniform compression (which I understand)

3. Yielding for flange in compression at various orientations. Not sure I quite understand this.
(There are no examples for angle in bending either?)

Mn = 1.3My

What is My defined as?

Is: My = Fcy*Sc? therefore, Mn = 1.3*(Fcy*Sc)?

or does My = Fcy*Sc need to be divided by ny = 1.65 or nu = 1.95?

Please advise.

Then they address lateral-torsional buckling and I do not quite understand what they are doing.

They say that:

When Me <= My, Then: Mn = (0.92-0.17*Me/My)Me

Me is later defined for different scenarios such as:

1. equal legs
2. lateral-torsional restraint at point of max bending moment or no lateral-torsional restraint
3. leg tip in tension or compression, etc.


My question is:

How is My defined?

Is My = Fyc*Sc?

As before does My need to be divided by nu or ny?

 

[ash060]

You allowable moment is My/ny.

There are 3 limit states

1) local leg buckling (which depends on how it is bent)
2) Yielding
3) lateral-torsional buckling

All 3 need to be checked