Aircraft versus Steel

[AZCat]

There will be. Even if you're taking an EE PE exam the general portion will have some basic engineering stuff. Some easy structural and civil and geotech stuff.

Aaagh! I thought I was done with that when I took the FE! I had this weird question about airport runways that I hadn't the foggiest clue how to answer.

 

[Newtons Bit]

Aaagh! I thought I was done with that when I took the FE! I had this weird question about airport runways that I hadn't the foggiest clue how to answer.

Yea, the transportation stuff is odd, but it should only be a small percentage on the general part of the exam. You can definitely pass with getting all of it wrong.

 

[AZCat]

Yea, the transportation stuff is odd, but it should only be a small percentage on the general part of the exam. You can definitely pass with getting all of it wrong.

Good - you had me worried there for a bit. I don't take it until next fall so I should have plenty of time to prepare (right?).

 

[leftysergeant]

Er...For the benefit of a non-engineer, would it not be SHEAR that cut those wing-and-fuselage-shaped holes in the side of the troop ship?

There was clearly, to my mind, no explosion outside the huill, or the engines and wings would have been blown back the way they came, or at least a considerable distance to either side of the hole. Everything was still firmly attached, to include the horizontal and vertical stabilizers (they left imprints) at the time the fuselage entered fully into the hull except for engine, which apparently broke loose and bounced off. Probably hit over a bulkhead of some substance.

So much for the twoofers who think the cartoonish imprint of the planes on the WTC were TOO close to the right shape. And there is no sign here that the aircraft crumpled a bit lengthwise.

 

[AZCat]

Er...For the benefit of a non-engineer, would it not be SHEAR that cut those wing-and-fuselage-shaped holes in the side of the troop ship?

There was clearly, to my mind, no explosion outside the huill, or the engines and wings would have been blown back the way they came, or at least a considerable distance to either side of the hole. Everything was still firmly attached, to include the horizontal and vertical stabilizers (they left imprints) at the time the fuselage entered fully into the hull except for engine, which apparently broke loose and bounced off. Probably hit over a bulkhead of some substance.

So much for the twoofers who think the cartoonish imprint of the planes on the WTC were TOO close to the right shape. And there is no sign here that the aircraft crumpled a bit lengthwise.

I'd say yes, but Newton's Bit knows more than I do.

 

[BenBurch]

Well, just looking at the hole it is hard to determine what the failure was exactly. The thing you want a picture of is the INSIDE of the hole, then it would likely be clear.

 

[defaultdotxbe]

Well, just looking at the hole it is hard to determine what the failure was exactly. The thing you want a picture of is the INSIDE of the hole, then it would likely be clear.

(previously posted by TAM)

http://www.usmm.net/images2/waite2.jpg

 

[Newtons Bit]

Er...For the benefit of a non-engineer, would it not be SHEAR that cut those wing-and-fuselage-shaped holes in the side of the troop ship?

There was clearly, to my mind, no explosion outside the huill, or the engines and wings would have been blown back the way they came, or at least a considerable distance to either side of the hole. Everything was still firmly attached, to include the horizontal and vertical stabilizers (they left imprints) at the time the fuselage entered fully into the hull except for engine, which apparently broke loose and bounced off. Probably hit over a bulkhead of some substance.

So much for the twoofers who think the cartoonish imprint of the planes on the WTC were TOO close to the right shape. And there is no sign here that the aircraft crumpled a bit lengthwise.

Shear is probably how the exterior columns failed (I'd need to see some good pictures to really tell). More specifically you can call it one-way shear, where the member breaks along a single plane. There's also two-way shear, where an object shears through the member (think a bullet punching through a plate). It really doesn't "cut" however.

You're pretty much spot on though.