Why a one-way Crush down is not possible

[bill smith]

"Force" is irrelevant.

You exert 2 lbs of force on a steak using a steak knife, and the steak cuts.
You exert 2 lbs of force on a steak using a spoon, and the steak does not cut.

STRESS matters, force does not.

And even stress is not the ONLY criteria.
A steak exerts exactly the same stress (& force) on the knife that the knife exerts on the steak. The knife is stronger.

A column stub hitting a concrete floor produces equal & opposite forces in the concrete & in the steel column. That is irrelevant to which part fails.

Don't think that I'm going to get drawn into your word-games, bill. You don't understand. You don't listen. You don't process information. And you aren't honest about it.

I guess you are saying that the principle I utlined above does not hold then. Poor ole Isaac N. will be turning over.

If not I guess you are saying that part C (the identical in structure, but relatively the lightest 10% of the building) must have been sharper than part A (the lower , stronger 90% of the building)

Is that about it ? I'm trying to be Honest Injun.lol

 

[Heiwa]

Actually, they are not identical. In between A and C is the part of the building damaged in the impact, let's call it D. All of the parts of D that have broken loose and fallen prior to the collapse have landed on the top floor of A. So A has been damaged by falling debris and is carrying extra load before C even starts to move.

As C starts to move, it is crushing the already heavily damaged and fire weakened section D. D is being compacted between A and C, and is the first thing to impact A. This 'buffer' of material between A and C never magically disapears. It is damaging A before C gets there, all the way down, and is a major reason the crush up and crush down are NOT symmetrical (besides the obvious bias of gravity pulling in 1 direction).



I don't believe you are an engineer of any kind if you can make a statement like that.

Sorry - in my model there is only parts C and A. Anything between parts C and A disappears to enable a free fall drop C on A. No part D!

Actually there is nothing between C and A except virtual columns that disappear due to FIRE!

But let's assume there is a part D on top of part A.

So you suggest part D is compacted between C and A, and then that this part D impacts part A.

Doesn't part D also impact part C?

And ... part D is damaging part A before part C gets there???!!!??? all the way down!!!!

Please, do you suggest that part A is one-way crushed down by a part D of the building that was between A and C before impact? But it was only air? Nothing!

And please - gravity does not pull in one direction! Gravity is a force of attraction between two masses. Both masses are attracted. It is not like love!

 

[Heiwa]

my prediction? this thread will end up like all others. the truthers will get frustrated and resort to calling the debunkers: "government loyalists", "bush lovers", or even "traitors".

any bets?

Of course! But you have already lost! I never get frustrated with people. BTW topic is something else.

 

[Heiwa]

"Force" is irrelevant.

A column stub hitting a concrete floor produces equal & opposite forces in the concrete & in the steel column. That is irrelevant to which part fails.

Thanks for your opinion. Topic is what support elements fail first in my model! The weaker ones (above) or the stronger ones (below). It is very relevant.

 

[bill smith]

No one changed your words, although I corrected the spelling of "mation" to "motion". I interjected. There's a difference bill, in the future I would be obliged if you refrained from making false accusations of me commiting illegal actions. There's no reason to be petty.

from BS-
"Whatever downwards force the moving body exerts on the stationary body fixed in the ground is reciprocated by the stationary body equally and oppositely. After that it depends which is used up first. Think of WTC1 and what should have happened. You can also correct me if I'm wrong."

You and Heiwa have stated the lower section was more rigid. Do you think the coefficient of restitution (or coefficient of elasticity) was the same for the upper and lower sections? What effect do you think rigidity has on the coeffcient of restitution? Would it be higher or lower? If during the collision, additional mass was added to the collision (by way of additional falling debris), what effect does it have on the duration of deformation? Does this change the impulse momentum equation of these two identical pieces?

I'll give you a hint, the additional falling debris changes the impulse momentum equation. Instead of an exoergic collision you end up with and endoergic collision.

Let's not mince words. You know what I mean about not changing my text. Let's say no more about it.

I imagine that the falling 'block' C would be structurally weak, not being attached to anything top or bottom. A prime candidate to shatter and fall to bits on impact with the stronger more rigid 90% of the building. There was no 'additional' rubble. It all came from the impact of C on A. What's more the smaller the pieces the more like a liquid it would behave, running round the core columns and placing little coherent force on them.

 

[Heiwa]

... Heiwa have stated the lower section was more rigid.

No, Heiwa does not state that anything is more rigid. Pls discuss topic.

 

[tfk]

Hey Heiwa,

I'm writing an answer to your post.

In the meantime, just out of curiosity, without looking it up, do you know the difference between a screw & a bolt?

Do you know what dimension on a X" pipe thread measures X"? (For X < 12").

Why do "flat washers" exist?

Just curious how familiar you are with some of the arcana of your field.

tom

 

[bill smith]

My full scale model is very simple - just horizontal elements of mass m with vertical supports below included in m. And part C (14 m) impacts part A (97 m) after a drop. Just answer the question: What elements fail first after impact and compression?
Then we can discuss.

When you think about it C is just a disconnected and heavily damaged part of the entire structure. When it impacts the stronger rigid part A it can only distort and fall to pieces and end up sitting on top of part A or falling off to one side.

 

[Heiwa]

Do you think the coefficient of restitution (or coefficient of elasticity) was the same for the upper and lower sections? What effect do you think rigidity has on the coeffcient of restitution? Would it be higher or lower? If during the collision, additional mass was added to the collision (by way of additional falling debris), what effect does it have on the duration of deformation? Does this change the impulse momentum equation of these two identical pieces?

I'll give you a hint, the additional falling debris changes the impulse momentum equation. Instead of an exoergic collision you end up with and endoergic collision.

Let's start with some definitions for us less educated:

Exoergic - relating to a process that releases energy
Endoergic - relating to a process that absorbs energy

Topic is part C impacting part A, whereby parts C and A compress, and then elements in part C or part A fail. Question is what elements, e.g. in C or in A or both. Impact + compression + failures = collision.

The C/A impact is supposed to be instantaneous (t=0) and it is exoergic. Compression will take some time and it is endoergic.
Failures of elements are also endoergic.

So a collision is both exoergic and endoergic. Topic is what elements in C or A fail first endoergically.

My suggestion is in C.

After failures and/or displacement of failed elements and part C, further exoergics take place. In my view further local endoergic processes then take place and there is no one-way crush down.

 

[Heiwa]

Hey Heiwa,

I'm writing an answer to your post.

In the meantime, just out of curiosity, without looking it up, do you know the difference between a screw & a bolt?

Do you know what dimension on a X" pipe thread measures X"? (For X < 12").

Why do "flat washers" exist?

Just curious how familiar you are with some of the arcana of your field.

tom

Yes I know! Don't worry.

 

[Furcifer]

I imagine that the falling 'block' C would be structurally weak, not being attached to anything top or bottom. A prime candidate to shatter and fall to bits on impact with the stronger more rigid 90% of the building. There was no 'additional' rubble. It all came from the impact of C on A. What's more the smaller the pieces the more like a liquid it would behave, running round the core columns and placing little coherent force on them.

You need to start thinking that the bottom of the upper section impacted with the top of the lower section. Not top 10% C and bottom 90% A. It's a fallacy.

Likewise, plate steel if the furthest thing from liquid I can imagine.

 

[Heiwa]

When you think about it C is just a disconnected and heavily damaged part of the entire structure. When it impacts the stronger rigid part A it can only distort and fall to pieces and end up sitting on top of part A or falling off to one side.

Something like that. But let's be fair! C is not damaged before impact but will be after impact. And get stuck on top of A.

 

[twinstead]

In my view further local endoergic processes then take place and there is no one-way crush down.

That's your problem right there. This is about what is "in your view". From what I have seen, a lot of pretty qualified people disagree with you. Are you suggesting that people on this forum who have carefully and patiently tried to explain to you where you are wrong don't know what they are talking about?

What exactly is your position on the many professionals who disagree with you? Do they just not "get" it, or is it more sinister than that?

 

[Furcifer]

Let's start with some definitions for us less educated:

Exoergic - relating to a process that releases energy
Endoergic - relating to a process that absorbs energy

Topic is part C impacting part A, whereby parts C and A compresses, and then elements in part C or part A fail. Question is what elements, e.g. in C or in A or both. Impact + compression + failures = collision.

The C/A impact is supposed to be instantaneous (t=0) and it is exoergic. Compression will take some time and it is endoergic.
Failures of elements are also endoergic.

So a collision is both exoergic and endoergic. Topic is what elements in C or A fail first endoergically.

My suggestion is in C.

After failures and/or displacement of failed elements and part C, further exoergics take place. In my view further local endoergic processes then take place and there is no one-way crush down.

In terms of the open system we are talking about, the addition of mass during the deformation period is exoergic.

Granted this isin't a truly exoergic collision, but gravity will accumulate more mass on the lower section than it will on the upper. The upper section will not be deformed as much as the lower.

Upper or lower, which was more rigid and how does it effect the coefficient of deformation?

 

[Furcifer]

No, Heiwa does not state that anything is more rigid. Pls discuss topic.

Oh, well I'm pretty sure someone was using your account and posting non-sense about the "lower more rigid section".

 

[bill smith]

You need to start thinking that the bottom of the upper section impacted with the top of the lower section. Not top 10% C and bottom 90% A. It's a fallacy.

Likewise, plate steel if the furthest thing from liquid I can imagine.

Do you mean the steel of the 48 floor pans that the concrete was poured into on each floor ? Each one 1/48th of an acre in size ? I think they must have vanished in that 9/11 way. There should be a total of 5,000 of them in each footprint but I'm darned if I can find a single one. Nah...they must have vanished...

The rest was a few bits of concrete and a fair amount of loose steel. That was about it really.

 

[tfk]

I guess you are saying that the principle I utlined above does not hold then. Poor ole Isaac N. will be turning over.

Unsurprisingly, you guess "wrong".

There is no "principle" to what you said. It was a meaningless string of words.

Nothing I said would disturb Sir Isaac's slumber in the slightest.

Try reading what I wrote again. (Fruitless, I know.)

If not I guess you are saying that part C (the identical in structure, but relatively the lightest 10% of the building) must have been sharper than part A (the lower , stronger 90% of the building)

Is that about it ? I'm trying to be Honest Injun.lol

You're lack of honesty just becomes more glaring every time you profess it.

I'll give you a big hint here, bill. Stop GUESSING at what I mean. On the rare occasions that you honestly try to understand what I've said, you've proven yourself no good at it. And you are even worse in the all-too-common cases - like this one - when you attempt to twist my words in a vain attempt to be clever.

lol.

I mean what I say literally. Take them that way.

If you had bothered to follow along my last several posts, you might have discerned the core points.

1) Force doesn't matter to parts failure. Stress does.
2) The collapse of the tower was NOT one single event. You can not treat it as such. It was a sequence of 116 separate events, i.e., floor by floor.
3) The lower part of the building was not significantly "stronger" in the specific way that matters to the building's destruction. Because the beams buckling was not the principle failure mode. The joints snapping was.

Now, if you'll excuse me...

 

[tfk]

Yes I know! Don't worry.

Share.

tom

 

[ozeco41]

You are off topic (my model) a little but allow me some comments.

I am certainly discussing what happened with WTC on 9/11 and how your model relates to WTC on 9/11.

My explanations are accurate explanations of what happened with WTC, as are leftysergeant's Your earlier posts before you moved to this thread showed that you understood my explanations yet now you deliberately choose to return to your models which are fantasies and not analogous to WTC 9/11.

Several others seek to humour your fantasy. It is a moot point as to who is off topic. This sub-forum is WTC and 9/11 so your model is of the topic of the forum and I am On Topic of the forum

However, since you choose to discuss your fantasy model and not what happened with WTC, there is no point me debating further.

...I'll give you a second chance = topic! What fail's first, when part C collides with part A in my model?

Thank you for the offer. However I do not wish to discuss your model where it departs from what happened with WTC on 9/11. My objective is to discuss WTC, not fantasies.

Cheers

 

[bill smith]

Unsurprisingly, you guess "wrong".

There is no "principle" to what you said. It was a meaningless string of words.

Nothing I said would disturb Sir Isaac's slumber in the slightest.

Try reading what I wrote again. (Fruitless, I know.)



You're lack of honesty just becomes more glaring every time you profess it.

I'll give you a big hint here, bill. Stop GUESSING at what I mean. On the rare occasions that you honestly try to understand what I've said, you've proven yourself no good at it. And you are even worse in the all-too-common cases - like this one - when you attempt to twist my words in a vain attempt to be clever.

lol.

I mean what I say literally. Take them that way.

If you had bothered to follow along my last several posts, you might have discerned the core points.

1) Force doesn't matter to parts failure. Stress does.
2) The collapse of the tower was NOT one single event. You can not treat it as such. It was a sequence of 116 separate events, i.e., floor by floor.
3) The lower part of the building was not significantly "stronger" in the specific way that matters to the building's destruction. Because the beams buckling was not the principle failure mode. The joints snapping was.

Now, if you'll excuse me...

So you agree that the following is true and I can quote you on this ?

''Whatever downwards force the moving body exerts on the stationary body fixed in the ground is reciprocated by the stationary body equally and oppositely. After that it depends which is used up first.''

1. In this case downwards force (gravity) and the mass of C is what causes the stress on the elements of part A and gravity is what causes the stress in prt C as it becomes impaled of the upright columns of part A.

2. If the collapse was floor-by-floor then one floor of A was destroyed for each one of C that was destroyed. I'll even give you two A to one C and still come out with half an intact building lol

3 How did the joints snap from a homogenous compressive collapse (straight down) ? You would need side pressure to snap the joints.

4. Oops....no 4.