What is the Optimal Wall Thickness for a Square Tube Supporting a Static Load?

[james ichi]

I need to make a steel beam ( or aluminum) of square tube ( box beam) 10 feet long with a balance point 2 feet from one end. The short end will have 60 lbs on it and the long end will have 30 lbs. how thick of a wall will the square tube need to be to hold the static load?

 

[berkeman]

I need to make a steel beam ( or aluminum) of square tube ( box beam) 10 feet long with a balance point 2 feet from one end. The short end will have 60 lbs on it and the long end will have 30 lbs. how thick of a wall will the square tube need to be to hold the static load?

Welcome to the PF.

What is the context of your question? What is this beam to be used for? What is your background in this type of design?

 

[james ichi]

My background is minimal. It's part of a art instalation.

 

[berkeman]

My background is minimal. It's part of a art instalation.

Who will be held liable if you take advice for this on a web forum, and it fails and hurts some people? Can you ask for help from your ME department instead?

 

[james ichi]

On one but myself

 

[jack action]

Unfortunately, your setup is a very particular one and cannot be resolved easily by quick calculations from common cases.

Your forces don't seem to be balanced, thus a twisting torque will be applied at the junction of the beam and support. The design of that junction will be critical and how you intend to do it is crucial for the calculations.

Also the thickness depends on the size and the material of your square tubing (Usually, a larger square can have a thinner wall and aluminum needs to be thicker than steel for a given size).

The good news is that an engineering student under proper supervision can do such a task. So I also suggest finding a local university with an engineering department; You might find an helpful teacher that is willing to give some real work experience to one of its student.

 

[james ichi]

And here I though there were people that such things...