The Conservative Cave
Interests => The Science Club => Topic started by: Chris_ on April 07, 2010, 02:47:18 PM
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Interesting to see the massive amount of deflection load required to result in failure.......
doc
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I remember back when we ran the same tests on the 757 and 767 series. It took 20g at 150% of ultimate load to get the wing on the 767 to fail, and the mode of failure was the fasteners holding the wing/spar assembly into the wing box literally tore out of the web of the wing box. (the wing and spar were ready to take more punishment, as as fabricated.)
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does that really count as a failure? Seems very sufficient to me. Not that I know anything about it.
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does that really count as a failure? Seems very sufficient to me. Not that I know anything about it.
Doesn't matter HOW the wing separates from the fuselage. It's all pretty useless to the hundreds of screaming, panicked passengers inside when it does.
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Doesn't matter HOW the wing separates from the fuselage. It's all pretty useless to the hundreds of screaming, panicked passengers inside when it does.
lol.
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I thought their ultimate failure was delivering the Tanker they thought the USAF wanted and not what the USAF wanted
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I remember back when we ran the same tests on the 757 and 767 series. It took 20g at 150% of ultimate load to get the wing on the 767 to fail, and the mode of failure was the fasteners holding the wing/spar assembly into the wing box literally tore out of the web of the wing box. (the wing and spar were ready to take more punishment, as as fabricated.)
You can't tell much from the crappy video, but if you watch for where the "flash" comes from when the failure occurs, it appears to be coming from the wing root.......in approximately the same area as you described on the 757 & 767 series.....
It would stand to reason, from an engineering perspective, that assuming that the wing itself has no structural flaws, the most likely point of failure would be the attachment points to the next larger assembly.......where the load vector would be focused when force is applied to the wing, in the manner that is shown in that test jig.......the force is being applied from the wingtip through the "center of lift" which appears to be about 2/3rds of the way back from the tip......the break would therefore tend to happen at the "fulcrum"......(the wing becoming, in essence, a lever).
doc
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The reason the video is so "crappy" is that it was shot with el cheapo (expendable) closed circuit video cameras. Back when 757/767 were first rolling out, they shot it on el cheapo 8mm film, I believe for the same reason.
Reason being, nobody is allowed in that building when the test is underway for safety reasons. Max load on a 767 is in the neighborhood of 500,000 pounds, and the wing is designed to carry all of it once the wheels leave the runway. The ultimate load test ran that 500,000 pounds up to 20g - 10 million pounds of force - before the wing failed, and like I said, it was the web of the wing box itself that failed. Spalled metal was flying through that building with all of that 10 million pounds of force when the wing let go. Pieces punched through cinder block walls like butter. The test engineers figured that putting more expensive cameras in with that was contra-indicated.