Hardfire: Physics of 9/11

[A W Smith]

psikeyhackr joins the battle creek navy

.
Suppose you had two boxes of Captain Crunch and you hold one in each hand with you arms spread as far as possible. Then you smash them together as hard as you can. Is the box in you left hand going to remain intact and crush the one in your right? Is the box in you right hand going to remain intact and crush the one in your left? NO! They are both going to get crushed. That is going to consume energy in both.

Stundied, Are you here to amuse us? cause that's pretty funny

And who can forget judy woods wheat chex,

 

[Toke]

People keep talking about FLOORS and thinking about those square donut floor slabs. Didn't the CORE of the top 16 stories of the north tower have to come down on the CORE of the stationary portion below?

Where did the goalpost go?

The speed of falling would increase all the way down.
The speed of acceleration would also increase as the relationship between falling and stationary masses changes.

I get these from Your model, try address any errors I might have made.

 

[tsig]

Stundied, Are you here to amuse us? cause that's pretty funny

And who can forget judy woods wheat chex,

What do they have against food? Lemons, cereal, pizzas they all fall underneath the twoofer wrath. Think of the starving children in China!!

 

[psikeyhackr]

Where did the goalpost go?

.
I don't give a damn about sports I don't talk about goal posts. The core went through the whole building so the core of the top had to come down on the core of the bottom. That is where half the weight was supported so just talking about FLOOR makes no sense. I make it a point to say LEVELS not Floors.

The speed of falling would increase all the way down.
The speed of acceleration would also increase as the relationship between falling and stationary masses changes.

I get these from Your model, try address any errors I might have made.

.
Where did you get that quote from and who are you accusing of saying it? I just did a search of my FALL OF PHYSICS for the word "speed" and that quote ain't there.

If you claim it is in one of my videos specify the time.

psik

 

[funk de fino]

I don't give a damn about sports I don't talk about goal posts. The core went through the whole building so the core of the top had to come down on the core of the bottom. That is where half the weight was supported so just talking about FLOOR makes no sense. I make it a point to say LEVELS not Floors.

The top section tilted and rotated. The core columns then broke. They did not fall down and hit the columns below square on.

All the top section had to do was fall down on the first intact floor below and break the floor connections. Guess what hapened next?

A large section of the core remained standing some time after the collapse front had passed, therefore the core did not get crushed down. Try again.

 

[psikeyhackr]

Cereal Collapse

Stundied, Are you here to amuse us? cause that's pretty funny

And who can forget judy woods wheat chex,

.
I didn't select Capt. Crunch by accident but are you claiming one of the boxes would not be crushed? Wheat Chex is easier to say than "perimeter wall panel". The NIST hasn't told us the numbers and weights of each of the 12 types. Though it is very important that we know that the original building design called for 14.

psik

 

[psikeyhackr]

The top section tilted and rotated. The core columns then broke. They did not fall down and hit the columns below square on.

All the top section had to do was fall down on the first intact floor below and break the floor connections. Guess what hapened next?

A large section of the core remained standing some time after the collapse front had passed, therefore the core did not get crushed down. Try again.

.
You are talking about the south tower, I said 16 stories so that is the north.

The south tower brings up a whole 'nuther set of issues.

psik

 

[A W Smith]

.
I didn't select Capt. Crunch by accident but are you claiming one of the boxes would not be crushed? Wheat Chex is easier to say than "perimeter wall panel". The NIST hasn't told us the numbers and weights of each of the 12 types. Though it is very important that we know that the original building design called for 14.

psik

yes you didnt select gravity ether. funny whenever a truther wants to claim that physics was violated that day, they choose a two dimensional horizontal conservation of momentum example which conveniently omits both scaling and the acceleration due to gravity

nice try but your not the first nor will you be the last to try that trick.

 

[R.Mackey]

Back from a short vacation. And I see FOUR NEW PAGES of nonsense.

I'm tired of reporting people. This is just silly. I may as well leave the last bit here as lasting proof that the Truth Movement either cannot engage intelligently, or refuses to.

---

For those engaging psikeyhackr (and psik himself), please review this. The tone never changes. Don't waste your time.

---

There was a comment (from AboveTopSecret, I think) regarding my use of the word "strength" in my simplified collapse model. I should note that I define strength quite rigorously in the first show, so I'm quite aware of the term.

What I was defining in that model was, specifically, an energy cost associated with destroying the support columns (perimeter and core, I made no distinction, it's a simplified aggregate). This energy is calculated by estimating the force resisted by the columns -- i.e. their yield strength (not yield stress) -- times the distance they resist before buckling (the yield strain times their length) at which time their resistance effectively becomes zero. Force times distance. Energy. That's the units I used.

This isn't quite the same as some other definitions of "strength," but since I defined it carefully and even gave you the equations I was using, there should be no confusion. In normal parlance, the actual quantity I'm estimating here is closest to "toughness," something I haven't seen any of my various nit-pickers mention yet. Toughness is defined as energy absorption of material before rupture, i.e. yield strength times yield displacement per unit volume, which matches. However, the reason I didn't use this -- very specifically did not -- is because we have no ready way to calculate how much of the material actually ruptures. If the columns failed under axial strain, that would be easy, but it doesn't. It buckles. Only a very small fraction of the material actually ruptures (the parts at the kinks), and so "toughness" is not useful, and bringing it up will only confuse my derivation.

It should be clear from my lecture that I do, in fact, understand the terminology. The criticism seems to be that I don't, and if I don't the whole thing must be wrong. Besides their premise being incorrect, this is an ad Hominem logical fallacy. So don't nit-pick, mmm'kay? Just sit back and try to learn.

---

Since the Truth Movement appears incapable of rational criticism, and those I intended this series for appear to understand it based on their responses to the Truth Movement, then I estimate that little to no clarification of the lecture is needed.

Therefore, let me propose a new focus for this thread, in case anyone is actually interested in being on-topic: If I were to do more shows, what would you be interested in seeing? What technical aspects are difficult to understand, interesting, or have broader educational appeal? I throw this open to the Truth Movement as well as everyone else who seems to get it. Thanks.

P.S.: Four pages of off-topic bickering here, several more on other forums, lots of Internet buzz -- and not one e-mail. I guess sending me e-mail and actually looking for clarification is unsatisfactory to those merely seeking attention. Nonetheless, the line is open if there are any technical questions.

 

[funk de fino]

RM

I think you needed to bold this part to drive it home.

P.S.: Four pages of off-topic bickering here, several more on other forums, lots of Internet buzz -- and not one e-mail. I guess sending me e-mail and actually looking for clarification is unsatisfactory to those merely seeking attention. Nonetheless, the line is open if there are any technical questions.

I will in future stop responding to psikey unless he starts a new thread or this is split.

 

[psikeyhackr]

What I was defining in that model was, specifically, an energy cost associated with destroying the support columns (perimeter and core, I made no distinction, it's a simplified aggregate). This energy is calculated by estimating the force resisted by the columns -- i.e. their yield strength (not yield stress) -- times the distance they resist before buckling (the yield strain times their length) at which time their resistance effectively becomes zero. Force times distance. Energy. That's the units I used.

This isn't quite the same as some other definitions of "strength," but since I defined it carefully and even gave you the equations I was using, there should be no confusion. In normal parlance, the actual quantity I'm estimating here is closest to "toughness," something I haven't seen any of my various nit-pickers mention yet.

.
http://www.youtube.com/watch?v=LXAerZUw4Wc

So your complaint about my model is what?

In your 3rd episode of Hardfire you have these 2-6 and 2-7 models where you have these flat masses "m" and columns "h" and you talk about scaling to the WTC. But how is anyone supposed to scale if they don't know the distribution of mass in the WTC?

psik

 

[Heiwa]

There was a comment (from AboveTopSecret, I think) regarding my use of the word "strength" in my simplified collapse model. I should note that I define strength quite rigorously in the first show, so I'm quite aware of the term.

What I was defining in that model was, specifically, an energy cost associated with destroying the support columns (perimeter and core, I made no distinction, it's a simplified aggregate). This energy is calculated by estimating the force resisted by the columns -- i.e. their yield strength (not yield stress) -- times the distance they resist before buckling (the yield strain times their length) at which time their resistance effectively becomes zero. Force times distance. Energy. That's the units I used.

It is noted in your model with upper part M = k m at start that what appears to be floors with mass m, are contacting/impacting each other and fuses when M drops due to gravity, upper part M becomes (k+1) m, i.e. bigger at every contact, &c, and that columns away from m, actually fitted between 2 ms below, fail.

So upper part M thus gets bigger - adds one m - every time it hits an m, when dropping on it, or M = (k + n) m after n impacts in your model.

I am sorry! This phenomonon that M = (k + n) m after n impacts has nothing to do with reality (as already pointed out several times ).

Actually - when M = k m impacts the first m, it is not columns remote from and not part of neither M or m that deform of fail or buckle, but M and m.

So at first impact you have to check how M and m deform. M may bounce on m! If M does not bounce on m, M and m suffer local failures.

As M and m suffer local failures, they cannot possibly fuse!

As m suffers local failures, it is not certain that elements far away from m (columns) fail.

As M suffers local failures, you have to check if M remains M. Maybe M = (k - 1) m after first impact?

After k impacts maybe M = (k - k) m = 0 (!) or rather k off m are ripped off M when M tries to destroy something.

The latter is not a new phenomenon!! It happens every time M collides with m.

Back to the drawing board, Mackey!

 

[Newtons Bit]

What I was defining in that model was, specifically, an energy cost associated with destroying the support columns (perimeter and core, I made no distinction, it's a simplified aggregate). This energy is calculated by estimating the force resisted by the columns -- i.e. their yield strength (not yield stress) -- times the distance they resist before buckling (the yield strain times their length) at which time their resistance effectively becomes zero. Force times distance. Energy. That's the units I used.

There's really two different options, and I don't think you're enveloping it quite right. You can assume that the columns get loaded and absorb energy, in which case the column absorbs elastic energy in loading up to the critical buckling stress AND plastic energy as the column buckles. OR you can assume that the upper block impacts the lower block acolumnsymmetrically(I'm trying to invent a new word here) and the columns absorb no energy.

If the system is detailed to allow plastic deformation (which the WTC isn't) then it will absorb a much greater amount of energy in plastic deformation. This is how earthquake resisting systems work. It's tough to figure out how much plastic deformation the WTC would undergo.

 

[DavidJames]

P.S.: Four pages of off-topic bickering here, several more on other forums, lots of Internet buzz -- and not one e-mail. I guess sending me e-mail and actually looking for clarification is unsatisfactory to those merely seeking attention. Nonetheless, the line is open if there are any technical questions.

We all know, Heiwa, psi and the others don't have the intellectual honest or capability to do anything but bicker and try to generate Internet buzz.

This forum is all they've got. People either don't realize or don't care, but feeding them with responses is quenching their thirst, satisfying their hunger. Remove that sustenance and they wither away.

 

[R.Mackey]

If the system is detailed to allow plastic deformation (which the WTC isn't) then it will absorb a much greater amount of energy in plastic deformation. This is how earthquake resisting systems work. It's tough to figure out how much plastic deformation the WTC would undergo.

yeah, it is tough. The assumption I use is that the columns absorb some energy, and that however the mechanism works, it works similarly in our model. I use the simple buckling assumption above just to give a basic formalism that allows scaling. This is basically your first choice, where the yield displacement takes into account both elastic and plastic deformation mechanisms. Note that I haven't worked out what that force or displacement is, precisely, but I do work out how it should scale.

Naturally, in the collapse itself, there are going to be all kinds of failure mechanisms. The simple mathematical model can be thought of as either a simplification or a probable upper bound.

I invite others to propose better equations and see how they scale in response. You will note that Heiwa persists in drawing his conclusions without presenting equations at all, and insists that scale does not matter... he is giving us a persistent object lesson in how to be very, very wrong. Equations first, conclusions second. Not the other way around. The other way around is working from a pre-conceived conclusion, and is not science.

 

[Heiwa]

There's really two different options, and I don't think you're enveloping it quite right. You can assume that the columns get loaded and absorb energy, in which case the column absorbs elastic energy in loading up to the critical buckling stress AND plastic energy as the column buckles. OR you can assume that the upper block impacts the lower block acolumnsymmetrically(I'm trying to invent a new word here) and the columns absorb no energy.

If the system is detailed to allow plastic deformation (which the WTC isn't) then it will absorb a much greater amount of energy in plastic deformation. This is how earthquake resisting systems work. It's tough to figure out how much plastic deformation the WTC would undergo.

According Bazant an 0.5 m drop of the upper part M (abt. 54 000 tonnes) of WTC 1 or say 0.27 GJ energy is sufficient to buckle 280+ columns below M, rip them apart at two locations each and throw them out of the way (to enable a drop of M). Sounds very little to me. Of course we can calculate the work/energy required to buckle and rip apart a column. A gravity drop of 0.5 m is not sufficient.

But it doesn't matter. Because when M contacts anything, it is the columns of M above impact zone that will fail, i.e. upper part M becomes a mess! WTC 1 would have withstood the gravity fed impact.

 

[Minadin]

Therefore, let me propose a new focus for this thread, in case anyone is actually interested in being on-topic: If I were to do more shows, what would you be interested in seeing? What technical aspects are difficult to understand, interesting, or have broader educational appeal? I throw this open to the Truth Movement as well as everyone else who seems to get it. Thanks.

I think that while most of the issues with the various failure modes that could have, and did, happen at the Twin Towers, are fairly well understood by the scientific and engineering community, it might be beneficial to touch on how and why the collapse progressed. There are a couple of non-intuitive issues at work here, which I believe you would be able to help clarify for laypeople. For instance:

- Until I took university courses in building technology and structures, I always assumed that steel was inherently fireproof because it is essentially non-combustible - you can't light it on fire easily, so why does it need fireproofing, how does that work, and why did it fail on Sept. 11? It seems that most people do not realize that steel weakens under heat, but once they are given some examples they can relate to, it seems obvious (blacksmithing, etc). There's also thermal expansion, which can vary between dissimilar materials, cause additional stresses, etc. I'm certain that you have to deal with this sort of stuff at JPL, but perhaps also pick Newton's Bit's brain a bit.

- I see people make bad collision analogies to try to intuit what they think would happen, or should have happened, at the WTC. A lot of the mistakes seem to come from making comparisons of similarly constructed, but differently-sized, objects colliding by themselves, in space (or occasionally on the ocean), but of course, the situation in the Towers is different because the lower portion was fixed to the relatively immobile ground, and both the upper portion and the lower were under a constant accelerative force (gravity) which doesn't stop accelerating the masses once one impacts the other. I think there are some people who don't understand that the upper portion is both increasing in mass and also being pulled through the lower structure.

- I always like to see posts by Reheat, Beachnut, and other aviators or other folks who know what they're talking about with regard to what the planes were capable of as far as speeds and maneuvers. Before I decided to do architecture, I flirted with the idea of becoming an aeronautical engineer. So, that sort of thing fascinates me, and since there are truthers around who still claim that the planes couldn't have done what they were purported to do, I would love to see more of the science behind why those ideas are wrong.

As I've said before, I did enjoy the 3 shows immensely. I'm not sure if the above are ideas for 3 more shows or if they would require more, or less, time. But, you asked.

 

[Heiwa]

You will note that Heiwa persists in drawing his conclusions without presenting equations at all, and insists that scale does not matter... he is giving us a persistent object lesson in how to be very, very wrong. Equations first, conclusions second. Not the other way around. The other way around is working from a pre-conceived conclusion, and is not science.

I like my equation PE<SE where PE is the potential energy applied to the structure by a dropping part and SE is the energy that the structure and the dropping part structure can absorb before total failures of all its elements and parts. PE<SE means the structure is not completely damaged. If PE<BE, where BE is the energy the structure can absorb elastically, then the dropping part bounces on the structure.
PE, SE and BE are quite easy to calculate if you do a proper structural damage/failure analysis of the structure as I point out in my articles. Every failure is associated with a certain energy. A quick calcuation indicates SE>1000PE! Actually BE>PE in one of my articles! Upper part should generally just bounce at a 'perfect' impact.

I know NIST suggests PE>SE but NIST does not calculate PE or SE. Reason is NIST will quickly find PE<SE!

 

[Minadin]

Normally, I don't respond to Heiwa, but, I just wanted to point out here that as a basic maths concept, 'PE<SE' is not a equation.

 

[Heiwa]

Maybe I should use PE≤SE to make it an equation? And that PE = the sum of the potential energy of all parts making up the upper part and that SE = the sum of the energy to fail all elements of the structure?