Joey Canoli wrote:Yes, I've read that. I'm also not aware of the limitations of the sim either. I don't know if it's possible to model the connection weaknesses, nor if they were done. From memory, the sim doesn't show much of the descent at all though, so I don't know if this even applies to the free fall time period. Educate me on this.
Now we're getting somewhere. I will return to this, here or another thread, as time permits.
Yes, it's theoretically possible to model the connections realistically, though maybe not practically so (at the time). I believe this is one of the aspects in which the sim falls short of reality. As is, you may be right about fracture, but both you and NIST cannot be correct.
Also from memory, they show core columns fracturing during the interior collapse, but don't remember ext columns fracturing, although this 'might' be cuz of it not extending to this time.
Yes, there is some interior connection failure. All I need to know is that buckling is depicted in the sim, the descent is depicted accordingly (slow) in the sim, and NIST specifically cites the "buckling region" when referencing the mode of collapse, not "fracture region". It is their explicitly declared collapse mechanism.
Why would anyone do that?
Well, as I explained above, you
apparently. I guess you weren't savvy to the contradiction between your thesis (which is also my best guess) and the NIST model. I threw them under the bus within a day of their report coming out. This issue is not the only reason, but that discussion IS OT.
NIST acknowledges the computational difficulties with them (there were 4)...
I have no doubts about the computational difficulties of simulations of "unprecedented complexity". It is precisely for this reason that I will be automatically skeptical of any result which:
1) is not accompanied by a larger body of incremental subsystem FEA analysis, validated and calibrated by physical testing along the way
2) appears to contradict the image record
NIST's sim fails on both counts. They partially satisfy #1, but in my opinion not to a sufficient extent given the size and complexity of the model. A washing machine lid, yes, collapse of WTC7, no. It would be okay to let them slide on this if it weren't for #2, and this is where the rubber hits the road. No one can say with a straight face that any of the collapse sims match the kinematic observables, though somehow it happens all the time.
BTW, it used to be it never happened, until Daniel came along and solved the issue of deflection scaling, which was universally assumed by debunkers prior to this time. It still is to this day by the uninformed few who haven't reached that stage of cognitive dissonance yet in an attempt to preserve the sanctity of the NIST report. Go ahead, you don't have to be a truther to throw them under the bus, I did it. Feels good.
...and their purpose. Which was to find out if there would be differences in the various collapse mechanisms.
Indeed, that was one of their purposes, but you state it in the singular. I seem to remember something else, another purpose; I'll need to check the report again and see if I can find it. Ah, here it is, first paragraph of the abstract in NCSTAR 1A:
This report describes how the fires that followed impact of debris from the collapse of WTC 1 (the north tower) led to the collapse of WTC 7;
This is the second sentence of the report! We see their primary
purpose is to explain the collapse of WTC7
. As a natural consequence of standard practice parameter sensitivity analysis, variations in scenarios were explored. Their primary purpose does not even include mention of modeling the collapse itself, so it may be tempting to say NIST was pre-positioning the physics sim under the bus from the get-go, but I'm not letting them off that easy.
The reason they switched from the fire sim to the physics sim is because the fire sim cannot model collapse, it can only impose damage such that initial conditions for collapse are approached. From there, the physics sim takes over and must provide an explicit causative mechanism for collapse
otherwise the collapse itself remains unexplained. Thus we see that the physics sim is the lynchpin of the NIST's proposed collapse explanation - it must be - which is stated as the primary purpose of the report in the second sentence.
Unfortunately, their collapse model contradicts one of my pet theories, rapid fracture skirting around the lower perimeter. If that's your theory, they contradict you, too. Pays to be aware of it. There's the bus...
It has become fashionable lately to claim that modeling the collapse itself was never a purpose of the report! That comparative damage simulation was the ONLY purpose. This is obviously false on casual inspection; the report states otherwise and, ultimately, of what value are comparative results between simulations that do not successfully model the underlying event?
Most interesting was the realization that removal of a section of column 79, with zero impact or fire damage, would result in a progressive collapse. They thus described an unexpected design flaw in 7.
Indeed they did. As I said, I've little choice but to be skeptical about the initial cause since the evolution from that point diverges rapidly. However, I do see the reasoning and it appears probable. Two things: I'm left wondering why all four sims diverge rapidly (have some ideas). Anyone who believes in HE CD now can say it's at least theoretically possible to take the whole bloody building down rather easily with small volumes, given sufficient planning. Sure, sure, the noise, I know; ears bleeding all over lower Manhattan.
I'm not trying to prove anything, as I said.
Speculation is fine. But I notice you are asking for proof in counterarguments, so be expected to be held to the same standard. You can always agree to disagree, or do the legwork to reinforce your position and hold firm. The one thing you cannot do is claim victory by simply ignoring facts and sound engineering mechanics principles, or by using a pair of contradicting claims to show the truth of one of them.
I've rather easily provided photo evidence that there is a reason to investigate this further.
Yep. Thanks. You've taken a small step towards an explanation of the collapse mechanics, all the same it's the right direction because it is incontrovertible observation as opposed to unprecedented simulation. As debunkers are fond of saying, nothing's stopping you from publishing your findings. It need not be perceived as refuting NIST, merely enhancing the description. But, if successful, you would supplant their model with a superior mechanism which is in fact incompatible with much of their stated position.
I have zero interest in trying to change anyone's mind here, but would enjoy seeing where the discussion went. That's all.
You succeeded in that regard. I don't expect you to change your mind, either, but would be pleased if you went past the first layer of the onion. Your instincts about the problem might be excellent. Better than NIST's.