[TowerTalk] polyrod

[Jim Lux]

It gets pretty complex, pretty quick, when you start looking at the
properties of angled catenaries.  I was trying to write some simple(!)
routines to generate catenary curves for various cases.  Turns out there's a
huge literature out there with all manner of analytical solutions, but I
think the upshot is that you wind up modeling the line as a series of short
ideal tension segments with pin (freely pivoting) joint ends.  No matter how
you skin it, catenary curves are a quite nonlinear spring, considered in
terms of the tension from the ends.
Fh = w / (8*h) * (S^2 - 4*h^2) << tension in horizontal catenary, given
weight per unit length(w), length of wire(S), and sag(h)

Start putting dynamic loads, or uneven wind loads, or the weight of
insulators, etc. into the picture, and it gets really complex.

----- Original Message -----
From: "Michael Tope" <W4EF at dellroy.com>
To: "Tom Rauch" <w8ji at contesting.com>; "Jim Lux" <jimlux at earthlink.net>;
"Roger K8RI on Tower" <k8ri-tower at charter.net>; "RICHARD BOYD"
<ke3q at msn.com>; <towertalk at contesting.com>; "Ken Claerbout"
<K4ZW at Staffnet.com>
Cc: <k7nv at contesting.com>
Sent: Sunday, May 01, 2005 9:17 AM
Subject: Re: [TowerTalk] polyrod


> I don't know if Kurt's analysis took this into account, Tom. It would
> interesting to see where the break even point occurs between the
> effect of the catenary in the insulated steel span and effect of the
higher
> tensile modulus in the composite guy span. I am CC:ing Kurt on
> this message, maybe he can enlighten us.
>
> 73 de Mike, W4EF.......................
>
>