most cycling loadnig events rarely exceed 50000 cycles. for cs and ss piping matl with uts of around 100000 psi, effect of mean stress on fatigue life hardly made any difference. just in case it does, the probable failure mode will be crack resulting in leak. for non hazardous service, this type of failure is still tolerable.
i think that the law of elastic shakedown would eventually kick in.
-----Original Message-----
From: Christopher Wright [mailto:chrisw@skypoint.com]
Sent: 20 April, 2002 6:35 PM
To: ?
Subject: RE: [PipingDesign] TRUNION TEMPERATURES
Don't forget that the plastic strain accumulates for ongoing cycles. The elbow probably won't fail on the first cycle, but there may be fatigue problems down the road.
Christopher Wright P.E. |"They couldn't hit an elephant from chrisw@skypoint.com | this distance" (last words of Gen. Received on Sun Apr 21 01:20:00 2002
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