[TowerTalk] Square tubing

[jimlux]

On 8/6/17 8:20 AM, Jim Thomson wrote:
> Date: Fri, 4 Aug 2017 10:27:54 -0400
> From: Charles Morrison <junkcmp at gmail.com>
> To: towertalk at contesting.com
> Subject: [TowerTalk] Square tubing
>
> <What changes or corrections are needed to Jim Lesson's formulas to
> <calculate survival of square tubing booms ?
>

It kind of depends on what he was calculating..
Stiffness goes as the section moment, which is proportional to the 4th 
power of the radius.


for square tube Ix = (OD^4-ID^4)/12
for round tube Ix = pi * (do^4-di^4)/64



Strength is more about radius and wall thickness. It's a bit tricky with 
square tubing because if the bend is exactly in line with the walls, 
then you have a very large cross-sectional area to spread the forces 
over. But if you're a little bit skew, then it's not hugely different 
than a round tube.



> <-Charlie N1RR
>