Strongest? Square Vs Round Tube

[hardsteppa]

after not finding the chassis braces I want, thinking I will just make my own. My understanding is, given an equal diameter and wall thickness, square tube will be stronger and flex less than round tube, is that right?

[JAS-25T]

given an equal diameter and wall thickness, square tube will be stronger and flex less than round tube, is that right?

square tube doesn't have a diameter. if you are talking about width/depth to an equivalent diameter, you can just look up the catalogues/tables on websites like onesteel. they provide all the data. "I" for deflection "Z" for bending. higher number = winning.

It's not in bending anyway it's related to area and I value.

square will look shit, if you're talking about strut braces... which I am assuming you are?

[hardsteppa]

more chassis bracing, like in boot, where it won't be seen. Thanks, will have a look for values chart.

[JAS-25T]

You've already got the front braced?

[warps]

Good answer, Jas-25T

Also round will have uniform strength in all directions, whereas square won't This can cause problems in some situations (although not likely to be a major issue in your case)

Shouldn't you be chasing strength vs weight?

Personally I prefer to work with square as it tends to be more flexible from a design/manufacturing point of view in terms of joins, attaching to things, drilled / bolted connections etc., and easier for manufacture. That's only one part of the equation (wearing my manufacturer's hat as opposed to engineer's hat)

Edited March 5, 2014 by warps

[warps]

Without looking at the tables I'd think that for a given diameter (side) and thickness, square would be stronger in bending, tension and possibly torsion (though I'm not 100% sure on the last one). It will weigh more though.

[hardsteppa]

for my application and usage the few hundred grams weight difference really isn't going to matter, but on that note the strength difference isn't going to be that massive either it seems.

For bending said tubing, either square or round, is press-bending as opposed to having mandrel bends, likely to be an issue in terms of creating a flex-point in the brace?

[warps]

Depends on the design and loading. A bent member in compression / tension (as most diagonal braces tend to be) will be much weaker than a straight one (look up Euler column buckling if you want a bit of an education), regardless of the bending method. Again, too many variables to say whether it will have a noticeable effect in your case (without looking at design / proposed loading etc.)

Press bending tends to reduce the section width (y direction), hence the Iyy value will be less, so in theory will be weaker in bending. In practice, this effect may be negligible so not worth worrying about.

[sweefu]

What are you bracing?
My bet is that you would not notice ANY difference whatsoever between square or round tube.

[rathinfotech]

Hi..you can check all the specification like thikness, strenth of round tubes please check reffer below reff..

http://www.pipestubings.com or http://www.buyflanges.com and http://www.aluminiumtraders.com