Aaaah coefficient of friction..........
Cant live with it, cant live without it.
It is the mechanical engineers female.
For pipes, I stick to Kellogg (showing my age here) - 0.2 to 0.5 for worst
case scenarios. P249 of 2nd Ed for a more complete description. If it goes
wrong, then at least I have a reputable text to blame.
Interesting how nobody seems to agree on the friction for a support, but
there have been some fairly precise claims on the accuracy of torque values
for tensioning bolts.
As Chris describes, friction is what keeps most of them tight.
Cheers
Steve McKenzie
-----Original Message-----
From: Christopher Wright [mailto:chrisw@skypoint.com]
Sent: Thursday, April 24, 2003 8:19 AM
To: ?
Subject: Re: [PipingDesign] Friction Effects in Piping Systems
>Do you have a clear design criteria for the friction
>load?
The closest I can come to a clear criterion is that I never depend on
friction to help. But as it's been said a couple of times in this thread,
friction needs to be assessed intelligently case by case--there's no
friction cookbook with a one-size-fits-all recipe.
Sometimes you have to make a couple of passes, sometimes with high friction sometimes with low friction. That's what was needed with free-standing spent fuel storage racks. Low friction gave reduced base shears and lower stress, since the racks were free to slide; high friction gave lower sliding displacements but greater uplifting displacements and higher stress.
If you're looking for friction to act as a restraint, say to support a span against lateral seismic motion, forget it.
Christopher Wright P.E. |"They couldn't hit an elephant at <a href="/group/PipingDesign/post?postID=PJ8USy3VkHZ-mob15CATrZrLFL9mF2_1UmPvyyLMVAGswJzy9wWdD4kduay2RMD2f-krsLpNzDu1Drw">chrisw@skypoint.com</a> | this distance" (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)<a href="http://www.skypoint.com/~chrisw">http://www.skypoint.com/~chrisw</a>
Your use of Yahoo! Groups is subject to <a href="http://docs.yahoo.com/info/terms/">http://docs.yahoo.com/info/terms/</a> Received on Thu Apr 24 07:55:00 2003
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