Re: [ATM] Help wth 3 tube truss

[Mark Holm <mdholm@telerama.com>]

ntent wrote:
> One could try to find some PVC tubing to place on the inside of the 
> existing tubes, and a friction fit.

If you mean placing the PVC coaxially inside the aluminum tube in order
to increase bending stiffness, I think that is a poor choice.  PVC
tubing, or generally most tubing will have considerably lower modulus
(inherent stiffness) and, for many grades of PVC tubing, relatively high
density.  Plus, putting material inside a tube, is the least effective
position for increasing bending stiffness.  If the only choice is
heavier wall tubing, then just getting heavier wall aluminum would be
better than most plastic tubes.  (I am excluding high stiffness
reinforced tubing such as carbon fiber from this class.)

-- 
Mark Holm
mdholm@telerama.com

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