PDA

View Full Version : Qantas 747-400 incident .. if it happened on a 787, what would happen?


JulieFlyGal
28th Jul 2008, 02:24
Just wondering about this since the 787 airframe is made of composite material and has no riveted sections, right? (I'm assuming the oxygen bottle blew up and caused a hole in the fuselage which is what's circulating around at the moment).

barit1
28th Jul 2008, 18:57
I believe the millions of carbon fibers cross-laid would be good rip-stoppers, don't you?

fleigle
28th Jul 2008, 20:58
Instead of one BIG bang there would be lots of smaller ones as the bit(s) bounce around inside.:ooh:

MUNT
30th Jul 2008, 08:26
I Don't claim to be in the know, but one could hypothesise a much less violent decompression, as the composite skin, I suspect, wouldn't 'peel'.

As for secondary effects of a compromised composite structure, I'd love to know!

Slats One
30th Jul 2008, 09:48
Having spent some time researching and working on this subject may I be allowed to comment:

(a) The composite structure is much stronger than the alloy structure and therefore will resist such attack much better and show far less damage or failure.

(b) The composite structure is much stronger than the alloys - up to a given point. Beyond that point -the composite will then fail in a (spectacualr)manner likely to create wider damage than that found in a lap spliced, tear stripped, "tear along perforated edge" type alloy skin. But sue of 'GLARE' can mitigate this -but still does not provide a load path sub structure.

A good performance analagy would be a modern Formula 1 car. You will know that the composite driver tubs of these cars resist massive impact and that thankfully there has been no fatality for years - indeed even extreme imapct loads have been taken by the tubs - loads far greater than any tube and steel spacefrme could ever have absorbed.

But one day, you may sadly see a composite tub be tested beyond its admitedly very high limits, on tat day all you will find is a scatter of shattered , razore sharp, composite shards, and a dead driver.

The is a photo of a Ferrari Enzo composite road car production model crash on the web- stressed beyond its load capabilities it has snapped into pieces in random fashion- with no load path routings of the fractures.

Expect the same with composite aircraft - gliders have already proved it- even if they are not made with 'GLARE' - as the 787 is.

Hope this helps. And don't get me started on Airbus tail fins and the the AA Airbus crash at JFK or the Tranasat rudder separation and fin mounting failures...

Fantome
30th Jul 2008, 09:52
But sue of 'GLARE' can mitigate this ???
............................................................ ......................

Slats One
30th Jul 2008, 10:06
Sorry- should read - use of GLARE - not - sue of GLARE!

GLARE is is the rare mix of composite and aluminium/alloy sandwich that the 787 is using in part.

It is much more damage tolerant than 'basic' composite and has other enhanced qualities- it is also very expensive.

spannersatKL
30th Jul 2008, 10:19
GLARE already in service on A380....appears to work well after much testing with Airbus.

Glare is a laminate of Alloy sheet sandwiching fiber/epoxy material...in a manner a bit like plywood..lighter than conventional alloy.

derbyshire
30th Jul 2008, 12:20
.....and it isn't frangible so does not "shatter" :)