In a message dated 96-12-24 12:12:18 EST, you write:
>Now for another "dumb question", what about the Philystran type of guying
>material. Any data on contraction or expansion? Also, given the variation
>in tension with the temperature what should I do? Should the guys be
>retensioned based on a change if temperature? If yes, how big a change in
>temp before doing this? I for one don't relish the though of retensioning
>the guys on two 120+ foot towers when it is 10 below.
>
Larry --
I've been going through my Phillystran literature and what I've been
able to find is the "effect of temperature on yarn tensile strength" and
"long-term creep" but no elongation vs. temperature data. Next time I talk
to Ken Knight, I'll ask him.
BTW, both of the aforementioned charts show 1) the benefits of
Phillystran/Kevlar over other synthetic materials and 2) the slow and small
elongation of tensioned Phillystran; at 10% tensile load, the elongation
in/in (x 10 -3) over a couple of years changes is practically constant. I
don't know what the immediate elongation when tensioned is.
It's probably too much to ask for Phillystran to be online and
subscribed to TowerTalk. Just FYI, Hy-Gain and Rohn are just 2 companies
that have employees that are subscribers.
73, Steve K7LXC
TOWER TECH -- professional tower supplies and services for amateurs
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: K7LXC@contesting.com
Sponsored by Akorn Access, Inc & KM9P
|