Subject: Carbon fiber construction
From: Rotary Engine
Date: 8/4/2011, 10:58 PM
To: AAA Put this in the To box



 Somebody with more experience than me should answer.
 Presumably most limited production carbon fibre epoxy structures are
 cured at room temperatue, if exposed to sunlight the internal
 temperature can exceed 80-100 degrees c hence degredation of the
 properties, this is why modern carbon fibre gliders are white.Commercial
 structures eg Boeing 787 are trated in an autoclave at elevated
 temperatures.
 Carbon fibre in contact with aluminium needs an insulating layer to
 prevent electrolytic corrosion.

 Peter Whitehead


The electrolytic corrosion is interesting. It is like dissimilar metals
corrosion. Carbon falls into the "other non-metals" category on the periodic
table, so you would think that would not be the source of the problem. Maybe
it is in the epoxy's used with the carbon fiber.

The problem with the composite failure, was described as the plastics
off-gassing and delaminating the structure.

The UV degradation described is likely the source of the race car failure in
a
car painted a dark color. I can not say for sure. It  is looking like all
non-metal construction should be painted and a light color.

Dale Davies


Dale,
I believe you are reporting urban legend. The only reason for a tub failure
is being designed too light. The reality is that many of the early F1 tubs
were much stronger than needed. In fact the manufacturer of most of the
carbon fiber used Hughes aerospace, had a kind of lease agreement with the
teams. They wanted the crashed tubs. They said they could learn more from a
crashed tub than months of lab testing.
Bill Jepson


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