Re: Effect of friction.

From: <Christopher>
Date: Thu Jan 15 2004 - 12:03:00 EST

>Please let me know if you consider effect of friction as permanent or
>temporary.

My rule is never count on friction to work in my favor. The exception that proves the rule occurs with high strength bolting, where friction induced by clamping loads is an important load transfer mechanism.

I will include friction to help bound a load analysis, but never as a mechanism to prevent unwanted motion, which accords with US building code practice. The basic problem is that the friction coefficient is not a dependable physical quantity. Also small vibration loads tend to induce a stick-slip effect that eventually makes adjoining parts 'walk' with respect to each other over time.

Christopher Wright P.E. |"They couldn't hit an elephant at <a href="/group/PipingDesign/post?postID=CCHgZQ7ADOuJdBLhOzL5SOypoieJPdIspS6SI_XaYlTmQ85Ah7-MdY6itGmLgm9Io-s2T8cskwe14srTRR0">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> Received on Thu Jan 15 12:03:00 2004