Is tube stiffer than bar?
Autolycus wrote:
"T i m" wrote in message
...
So, failing a 'yes' to the above, is there a simple formula (rule of
thumb) for how much 'stiffer' any particular steel would be for a
percentage increase in diameter please?
Say I go from 3/8 to 1/2" for example, would it be 25% or 33% or
something else stiffer?
Stiffness is proportional to the fourth power of diameter for a round
beam in bending, so 3/8 to 1/2 inch is a factor of 4^4/3^4, or 256/81,
or 3 and a bit, as we engineers say (or pi, or root 10).
Did not the state of Kentucky once legislate that pi=3?.
Robert
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