Re: Questions about the DH Comet

Date:         11 Sep 97 03:35:30 
From: (Gerard Foley)
Organization: The Greater Columbus FreeNet
References:   1 2 3 4
Followups:    1 2 3
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Janet and John (J& wrote:

: On 29 Aug 97 08:10:43 , in <airliners.1997.2000@ohare.Chicago.COM>,
: michael piersdorff wrote:
: >My understanding of the problem was that most of the in-flight
: >breakups were explosive decompressions of the fuselage resulting from
: >fatigue failure ... Any strength of materials textbook will show that
: >a square-ish corner is a tremendous stress raiser in a tension stress
: >situation, as a pressurised fuselage most certainly is.  The solution,
: >of course, was to go to the more or less oval windows one sees today.

: You should say "any strength of materials textbook written since the
: Comet crash investigations". Fatigue behaviour was not well known at the
: time, and the Comet crashes aided the development of the science
: immeasurably,

As a person working on endurance (fatigue) testing of materials (including
uranium as well as duralumin) in the period 1940-1945 I take issue with
the statement.  I believe poor calculation of stress raising, or
complete neglect of pressurization cycles as a source of fatigue
stress, was the reason for the fault.