Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


6061 T6 Aluminum

6061 T6 Aluminum

6061 T6 Aluminum

I was wondering if anyone can lead me in the right direction for the allowable bending stress (Fb) of 6061 T6 aluminum? This is my first project designing with aluminum.
 Is there a specific code for design that I should follow or should AISC be used other than the physical properties of the aluminum?

Any info would be greatly appreciated.


RE: 6061 T6 Aluminum

elastic or inelastic ?

i would normally limit elastic bending stress to Fcy = 35ksi.  this supposes that the section is stable in compression (crippling is not a problem, b/t < 8)

RE: 6061 T6 Aluminum

The Aluminum Design Manual 2005, by The Aluminum Association.  Very similar design principles, except ASD is easier.  Watch out for proximity to welds, the allowable stress is greatly reduced.

I also graduated from USF (South Florida, right?), Cheers!   

RE: 6061 T6 Aluminum

rb1957 has the allowable stress correct.  6061 T6 is strong stuff.  The Aluminum Association has a design standard for Aluminum.  AISC should not be used.  Aluminum's modulus of elasticity is somewhere around 10,000 to 11,000 ksi.  A good reference for aluminum design is Aluminum Structures, A guide to their Specifications and Design, J.Randolph Kissell & Robert L. Ferry.

RE: 6061 T6 Aluminum

6061-T6 Aluminum is Fy=35 ksi. Fu depends on whether it's plate, extruded, pipe, etc., and ranges from 38-42 ksi. E=10,100 ksi. Allowable bending stress per the Aluminum Design Maual (I have 2005 Edition) varies depending on the shape, and the slenderness of the elements that make up the shape. It even also has to do with whether you're designing a bridge or a building.

For the extreme fiber of a bending member in a building or similar structure, following are some typical values:

   Round Tube Fb=0.71Fy
   Square Tube or Single Web Shape Fb=0.61Fy
   Solid Rectangular or Round Fb=0.79Fy

In any event, you need the Aluminum Design Maual from The Aluminum Association... too many variables here. Also, aluminum allowable stresses are greatly reduced anywhere within 1" of a weld... and on, and on...

RE: 6061 T6 Aluminum

Thanks for the info guys. Much appreciated. I will definatley get the Aluminum Design Manual.

The member I am checking is actually an aluminum angle (L2 x 2 x 3/16) with a point load at its midpoint. The design is straight forward but I needed to get the allowable stress to detrmine if the section modulus is adequate.

Thanks again.

pelotoner - yeah South Florida. (Go Bulls!!) cheers.

RE: 6061 T6 Aluminum

Hi guys! what is the maximum pressure i can apply to an 6061-t6 Al rectangular tubing of 1.5" x 4" x 0.125" thickness. the total length would be about 40" and the pressure is going to be applied for a max of 20 seg

RE: 6061 T6 Aluminum

The ny, which is in the denominator below fy (yield stress), is 1.65 for buildings and for formulas in Table 3.4-3. This gives allowable stress for tension in beams, extreme fiber from bending of structural shapes bent around strong axis and tubes of 21.2 ksi. [page I-A-24, 3.4 Allowable Stresses.  "Aluminum Design Manual"

RE: 6061 T6 Aluminum

This allowable stress is reduced if it is welded, down to about 11ksi.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close