Photos © Airbus
Photos © Airbus
Posted on 02/16/2006 2:01:08 PM PST by A.A. Cunningham
Airbus A380 test wing breaks just below ultimate load target
The wing of the Airbus A380 static test specimen suffered a structural failure below the ultimate load target during trials in Toulouse earlier this week, but Airbus is confident that it will not need to modify production aircraft.
The airframer has been running load trials on a full scale A380 static test specimen in Toulouse since late 2004 (pictured below). After completing “limit load” tests (ie the maximum loads likely to experienced by the aircraft during normal service), progressively greater loads have been applied to the specimen towards the required 1.5 times the limit load. Engineers develop finite element models (FEM) to calculate the load requirements.
“The failure occurred last Tuesday between 1.45 and 1.5 times the limit load at a point between the inboard and outboard engines,” says Airbus executive vice president engineering Alain Garcia. “This is within 3% of the 1.5 target, which shows the accuracy of the FEM.” He adds that the ultimate load trial is an “extremely severe test during which a wing deflection of 7.4m (24.3ft) was recorded”.
The European Aviation Safety Agency (EASA) says that the maximum loading conditions are defined in the A380 certification basis. “The aircraft structure is analysed and tested to demonstrate that the structure can withstand the maximum loads, including a factor of safety of 1.5. This process is ongoing and will be completed before type certification.”
However Garcia says that the failure of the wing below the 1.5 target will require “essentially no modifications” to production aircraft: “This static test airframe has the first set of wings built, and we have refined the structural design for subsequent aircraft due to increased weights etc. We will use this calibration of the FEM to prove the adequacy of the structure on production aircraft.”
EASA says that it is aware of the structural failure but "cannot make a statement about the specific failure as it has not been officially briefed by Airbus on what the cause was, and the certification process is ongoing".
Garcia says that the FEM calculations had already established that the A380’s wing had “no margin at ultimate load. We had a weight saving programme and ‘played the game’ to achieve ultimate load.” However in earlier briefings, Airbus structural engineers had stated that it planned to carry out “a residual strength and margin research test” in 2006 after completing ultimate load trials.
The results gleaned from the static testing will be extrapolated for the future aircraft developments over the next 40 to 50 years says Garcia. “It is normal to refine and strengthen the structure of new heavier or longer range variants,” he says.
MAX KINGSLEY-JONES / LONDON
No margin, eh? Stoopid froggies.
Boeing is deeply saddened.
No, not really. ;)
To be fair, yes there is margin - 47%. They just didn't get to the planned 50%. Doesn't mean I'll fly one tho, but that's an economic decision.
As a proud American I gotta love it.
Their motto:
"Airbus--Nope, nothin' wrong here!"
Is this where they actually bend a wing until it breaks? or just a model? I think I remember them actually testing/breaking a 747 and the video is really cool.
there was a show about the 747 on Disovery once. In it, they showed the wing load testing. They flexed the wing like the A-380 pic shows. When it had reached it's breaking point, it exploded at the break. On the tube, it sounded like small arms fire. It had to be a LOT louder in the testing area. I'd prefer a Boeing product whenever possible.
Did anyone see the results of their ground test evacuating 600 people in 90 seconds? I have trouble believing that's possible.
"Garcia says that the FEM calculations had already established that the A380’s wing had “no margin at ultimate load. We had a weight saving programme and ‘played the game’ to achieve ultimate load.” However in earlier briefings, Airbus structural engineers had stated that it planned to carry out “a residual strength and margin research test” in 2006 after completing ultimate load trials."
They were going for Ultimate Load. They admit to not having margin in achieving that load, and they missed it. Their design was not adequate to survive *static* load test, dynamic testing will be worse.
"Is this where they actually bend a wing until it breaks? or just a model? I think I remember them actually testing/breaking a 747 and the video is really cool."
Did you ever see the one where they fired a frozen goose at the cockpit at 200 MPH? Now THAT was cool.
You mean to tell me that the wing tip has a 24 ft. up or down travel? WOW
Mike
My understanding was that the ultimate load was 1.5x the maximum use load. To me that is a 50% margin of safety in every day use.
But yea, in either case, it does look bad. Fortunately they're not likely to sell many of those monsters anyway. The 7E7's got their butts kicked.
I guess the bolt that hold the wing together were toulouse.
BTW: Are you the same Cunningham who posts on the Catholic threads?
I know a guy who breaks airplane wings for a living. He says it's a great deal of fun....
Actually, we typically shoot a four pound (MILSPEC) dead chicken at over 400 kts at the target....
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