Hi! Tom
This is now two photo's of failed items I've seen which, IMHO I have to
agree 100% with you every indication of fatigue is there. My training is
likely "old Hat" particularly considering modern alloy extruded tube but
I wonder what traceability exists of annealing/stress relieving :-
a) done to these and all frames ? (do certificates exist and where?)
b) what such heat treatment is actually called up on the metals and
complex joints in question?
c) what investigation has been undertaken with Rockwell Hardness tests
over the whole of the failed frames and in particular close to the
failure?
This is all shutting the gate after the horse has bolted but in the
total shape of things we need to know along with the question will new
ones be produced with up rated tubes and will they have an appropriately
designed heat treatment with a certificate?
NB I do have evidence that my nose leg has been "normalised".
Regards
Bob Harrison. G-PTAG
Robt.C.Harrison
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Tom
Friedland
Sent: 20 January 2007 04:52
Subject: Re: Europa-List: Mod 72 question
Hi Graham
I doubt that you will get an answer what caused the break. It looks to
be that it was most likely a tension break with perhaps some fatigue
factor. The upper tubes will have tension in the upper parts and that
will be increased by the thrust. There also could be some problem with
non annealed brittleness from the closeness of the weld.
The lower tubes should be ok as they have tension stress from weight
bearing but that is cancelled by compression.
But then what do I know. My engineering studies were 50 years ago! Now
I am just a dumb doc.
Tom
On 1/19/07, Graham Singleton <grahamsingleton@btinternet.com> wrote:
grahamsingleton@btinternet.com <mailto:grahamsingleton@btinternet.com> >
Roger
what type of failure was it, bending, shear or fatigue?
Graham
Roger Bull wrote:
>O.K. Bob, you woke me up!
>
>
>Rob Housman's answer is on the ball. Using Redux would necessitate
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