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Old July 9th 18, 10:38 PM posted to uk.rec.cycling
Ian Smith
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Posts: 3,622
Default Bent carbon frame?

On Mon, 9 Jul 2018 02:51:24 -0700 (PDT), wrote:
On Monday, 9 July 2018 07:08:32 UTC+1, Ian Smith wrote:
On Sun, 08 Jul 2018 14:29:15 +0100, Peter Parry wrote:
On Sat, 7 Jul 2018 12:38:15 -0700 (PDT),
wrote:

Cue a new rear mech and a spoke BUT a LBS insisted that the carbon
frame is also bent and they won't put it in a jig to straighten it.
How can a Carbon stay bend?

Stress any material beyond its elastic limit (yield strength) and it
will deform and stay deformed. You can't bend it straight again..


Really.

What do you think the yield stress of, say, a china plate is?
Do you think you can bend that so it stays bent?


Doesn't every material have an "elastic limit"?


Most materials have a limit to elastic behaviour. They don't all
yield when they reach it - some are almost perfectly elastic until the
point where they shatter into thousands of pieces. A dinner plate
doesn't reach a iield strnegth, then deform and stay defomred -
doesn't "deform", it shatters.

Many materials that do yield don't have a yield 'point' - even
relatively common stuff like stainless steel doesn't have a defined
yield point - it doesn't exhibit a pure elastic behaviour except at
infinitesimal strains.

regards, Ian SMith
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