Increase Strength with Aluminium: 30x30mm to 60x60mm and 3mm to 6mm

[Rado Gary]

Could anyone please help me?

If I have a piece of aluminium Angle that is 30mm x 30mm by 3mm thick and 1m long, if I were to substitue this with a piece that is the same thickness and length but 60mm x 60mm what increase in strength would I see?
If instead of increasing the size what would happen if I doubled the thickness to 6mm thick?

Please please help...

 

[nvn]

Rado Gary: That depends on how it is loaded. You have not specified how it is loaded yet. Also, you have not specified end constraints. The ends are pinned (simply supported), right? Is this a school assignment?

 

[FredGarvin]

Bending strength? Tensile strength? What loading? If it is in bending, did you think about looking at reorientation of the L shape cross section in relation to the deflection?

 

[Rado Gary]

Many thanks for the comments, I see I need to provide some more information.
I am a Radio Amateur and am looking to build a radio mast. I need this to be telescopic and cope with a heavy antenna around 220kg that also has a high wind loading of around 28 square feet.

In the Uk there is nowhere that manufactures radio towers as one offs to accommodate this kind of antenna, so I have decided to embark on this complex project myself.

If you have the time you might look at a German website www.hummelmasten.de here you will see the type of mast I am trying to replicate.

I would be prepared to discuss this project and my needs in more detail if someone wanted to provide me with structual calculatons for the mast. I would be prepared to pay for their advise and design calculations.

I need the mast to extend to around 30m (100ft) and cope with the antenna loading at windspeeds of up to 85mph.

So looking at what i have seen others use I am looking to build the mast out of equal angle aluminium and I am just pondering as to the differences in strength the same sectional aluminium piece would have if it were substituted for different thickness.

The lattice mast sections will be bolted together and each telescopic section will be 6m in length.

So my initial thoughts were to use 4inch equal angle 7075 T6 aluminium for the bottom section and this material would be 12mm thick. The dimensions for this being 780mm square.

The second section being around 610mm square and utilising the same size alumnium angle but I was wondering as to what effect to the strength of the overall secton would have if I reduced the material thickness to 6mm?

So a long winded explanation I know but why I am asking what effect the variations on material selection would have.

Now can anyone help me?

Kind Regards

Gary

My iitial thoughts are h

 

[nvn]

Rado Gary: A single structural angle (pinned-pinned column) with dimensions 102 x 102 x 12 x 1000 mm is 1.94 times stronger than the 102 x 102 x 6 x 1000 mm angle.

 

[Rybose]

http://towermast.willburt.com/products.asp