To: "SEAOC Newsletter" <seaint(--nospam--at)seaint.org>
Subject: Re: Welding Code AWS D1.1
From: Christopher Wright <chrisw(--nospam--at)skypoint.com>
Date: Fri, 16 Apr 99 17:51:51 -0500
>Thanks for your comment. I do agree with you with regards to stress
>concentration around a round hole. I consider this case a lessening of
>material due to hole cut outs,
Not true. The stress concentration at a round hole is 3 even where the
hole diameter is negligible with respect to the flange width.
>where is the logic in this that the 8" x1/2 flange can safely withstand the
>load but the 14 5/8 x 15/16 flange may become overstressed and develop
>cracks. Unless it is shown by tests that the smooth transition is needed to
>prevent the overstressing of the smaller flange.
The concentrated stress develops in the smaller flange right next to the
discontinuity, and it develops because of the mismatch in stiffness
across the interface width. The stress concentration doesn't apply to the
entire flange width, and will be a consideration for fatigue only. The
whole flange won't be overstressed but the small area at the
discontinuity sure will. Typically what happens is crack formation and
gradual extension under cyclic service loading, and fracture the first
time it takes a big hit.
Christopher Wright P.E. |"They couldn't hit an elephant from
chrisw(--nospam--at)skypoint.com | this distance" (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)