Alot of that doesnt make sense to me, in the real world. How is it I can smack a piece of round tube on something, and bend or dent it, whereas same thickness sq tube, will just bounce off and hurt my hand?
Ive also read sq is stronger than round, more surface area to spread the load on.
You know why the square just bounces and not bends? You are trying to bend 2 pieces of flat bar on the sides basicaly. Think of stand on a pop can, you put a dent in the side and the whole thing smashes down. Now do that with square and the load is at the corners to start with, so no smash,