Crash Test 2

[Fatstress]

Dear All,

So Boeing has carried out their composite fuselage 787 crash test...
Is it a new requirement only for composite fuselage or also for monolithic Aluminium ?

Regards

 

[ieaz123]

What?

 

[SWComposites]

What do you mean by "monolithic aluminum"?

The crash test was required to show equivalent safety to existing, aluminum fuselage aircraft.

 

[Fatstress]

Monolithic Alu, just the usual Aluminum sheet or plate, not laminates, ARALL, or Glare.

If I understand correctly, FAA required a full scale composite fuselage test article for the crash test. Cannot it be a smaller scale or only a few frame bays of fuselage structure only? Is there any background evidence to require such a test?

 

[rb1957]

if think FAA were worried about the new materials introducing new effects, responding to the loads differently, being upset by different things compared with what we "know" (ie monolithic Al skins ... 2024, 7075). I think scaling only works when you're comfortable with the material and the test to know that you're scaling the right parameters correctly.

 

[EdStainless]

I want to see them break the 787 wings. I watched the 777 tests.

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[40818]

How did the 777 test go, did they achieve ultimate load??

 

[SWComposites]

Yep, a little bit past ultimate load for the 777 wing test, right at the predicted failure load and location.

 

[EdStainless]

A380 didn't. They had to do a minor re-design to pass, but no re-test. I think that they made 148%. 150% is required. As I recall 777 went to 153%. They sure go with a bang.

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Still trying to help you stop corrosion.
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or edstainless@earthlink.net

 

[RPstress]

What did Boeing actually have to do for the 'fuselage crash test'?

 

[swearingen]

Trouble in paradise?

http://seattletimes.nwsource.com/html/boeingaerospace/2003889663_boeing180.html

If you "heard" it on the internet, it's guilty until proven innocent. - DCS

 

[Fatstress]

RPstress,

Answer to your question can be found in the folowing link...

http://www.iht.com/articles/ap/2007/08/24/america/NA-FIN-US-Boeing-787-Crash-Test.php

....dropping a 10-foot-long (3-meter) fuselage section from a height of about two stories to see how the carbon-fiber composites would hold up on impact.

 

[KENAT]

Oh, I got excited for a minute. I was imagining re-creating that crash they did in the early 80s with that old convair.

Now that looked fun!

KENAT, probably the least qualified checker you'll ever meet...

 

[Sparweb]

Why did Boeing drop the 787 fuselage only 15 feet, when they dropped the 737 fuselage 30 feet? Will they drop a 787 fuselage 30 feet at some later date?

How would this aircraft survive the type of crash experienced at Pearson airport in 2005?

http://en.wikipedia.org/wiki/Air_France_Flight_358

Would all the passengers get out after the type of fire that ensued? Building the entire fuselage from CF must be challenging from a FAR 25.853 point of view...

Steven Fahey, CET

 

[wes616]

Speaking of crashes....

thread1088-197935



Wes C.
------------------------------
No trees were killed in the sending of this message, but a large number of electrons were terribly inconvenienced.

 

[Sparweb]

...And why would Boeing drop a 737 fuselage section 30 feet anyway? FAR 25 doesn't seem to have that requirement. A drop of 19 feet will give a descent velocity of 35 ft/sec, like the criteria of 25.562 (35 ft/sec). But the landing conditions in 25.473 and .723 don't require this...

Steven Fahey, CET

 

[40818]

The 737 test was to evaluate the structual effects of an aux fuel tank on the structure in a crash.

http://citeseer.ist.psu.edu/626400.html

in the right hand side of the page is a pdf which will open up a report.

 

[RPstress]

Re deadly, deadly composites (see wes616's post), see the following from COMPOSITES PROCESSING 2006 27th April 2006, "Composites in Aircraft Crashes" by John Andrews - Post Crash Management Systems.

"...when test pieces were subjected to high kinetic energy impact at the same time as high temperature (1000ºC) flame, substantial quantities of respirable fibres were released."

The author says that to get really dangerous you need both impact and high temperature simultaneously. With regard to the A340 crash at Toronto he says:

"...because any high energy impact was not coincident with the high temperature fire, there was little or no release of respirable fibres. Additionally the weather was kind and a short rainstorm each day minimised the risk from respirable dust. The overall site hazards from this crash, which were expected to be severe, were easily managed with disposable coveralls and respiratory protection."

So, not exactly nothing to worry about, but not quite as bad as it could be.

PS: ally fuses can to burn through quite rapidly when flames from the outside impinge on them (Burn-through contributed to a few of the deaths at Manchester UK in 1985 - though most were toxic gas inhalation). A carbon laminate is a lot more resistant to burn through. On the other hand, you don't want it to increase FST dangers inside the fuse. Even external materials are increasingly subject to FST regs these days.

PPS: Swearingen and Fatstress, thanks for the Boeing fuse test links.

 

[tatsco]

I am amazed how many people defend Boeing"s expertise in COMPOSITES when I look at the schedule slippage.

JIM

 

[rb1957]

come on ! ... Everybody has schedule slippage on a new program ... look at all the slippages Airbus had on 380 ... i thin Boeing has decided to have one slip and take their lumps.