If it doesn't agree with experiment, it's wrong. Part II

[Stamuel]

Correct me if I'm wrong (I deleted my copies of the NIST reports a while back), but I seem to recall that NIST didn't force their FEA calculations to stop after initiation. The FEAs eventually broke down due to increasing structural failures going beyond what the software could handle.

My understanding is that we do not have the capability to come anywhere close to reliably modeling a collapse progression like what occurred in the towers or in building 7. If this is correct, it is not that NIST neglected to investigate how the buildings collapsed even though they could have done so. It's that they recognized that they could never do better than vague rough estimates (and that modeling progression was unnecessary). In other words, the investigation was as compete as was feasible.

Can anyone confirm whether this is correct?

 

[rwguinn]

Pretty much
Once failure occurs, you start adding variables to the equation set. Up until then , you are doing say, a million equations with a million unknowns. At rupture, you still have the million equations, but you now have a million + n unknowns. Which makes for a whole lot of possible solutions...

 

[KenRam]

Sorry Folks, I left the keys of the "Nutter House" in the hands of my Ex. She let out Criteria, FalseFlag and Yankee by mistake - although she still agrees with Yankee from the missile point of view and would love to have him send one into her because it will never penetrate - it will just bounce off. Aside: His wife must love him. And the same goes for FF and the "BIG C."

 

[Jaytje46]

Correct me if I'm wrong (I deleted my copies of the NIST reports a while back), but I seem to recall that NIST didn't force their FEA calculations to stop after initiation. The FEAs eventually broke down due to increasing structural failures going beyond what the software could handle.

My understanding is that we do not have the capability to come anywhere close to reliably modeling a collapse progression like what occurred in the towers or in building 7. If this is correct, it is not that NIST neglected to investigate how the buildings collapsed even though they could have done so. It's that they recognized that they could never do better than vague rough estimates (and that modeling progression was unnecessary). In other words, the investigation was as compete as was feasible.

Can anyone confirm whether this is correct?

Its just impossible to recreate the collapse, because of the millions of variables. truthers want to know exactly how each column, truss, floor, and interior behaved during the collapse, which is impossible of course. Thats why they are complaining that the WTC7 digital recreation made by NIST is not looking like the real thing. And than they can yell foul again, because in their belief, it should be easy to recreate the entire collapse.

 

[FalseFlag]

9/11 was investigated more than any crime in the history of the planet.

Where is all of the FBI evidence? How much evidence did the 9/11CR and NIST ignore?

It amazes me how much effort you skeptics have to put in to maintaining belief in the official lie. It's extraordinary.

 

[FalseFlag]

Would you be so kind as to briefly state exactly what these "certain conditions" are.

Thank you.

Nothing supported the falling portion of the building during the period of freefall. You know this.

 

[FalseFlag]

Moving the goalposts. You asked for where they explained free-fall, that was provided, now you're switching to asking a different question, why the exterior columns buckled.

https://pseudoastro.wordpress.com/2009/12/01/logical-fallacies-moving-the-goalpost/

Everyone on the board can see right through this.

Hank

This is laughable. NIST admits freefall, and the only thing they say is that the columns buckled. That is not an explanation, and you know it. Why did the columns buckle at exactly the same time. That requires an explanation.

 

[Wolrab]

Where is all of the FBI evidence? How much evidence did the 9/11CR and NIST ignore?

It amazes me how much effort you skeptics have to put in to maintaining belief in the official lie. It's extraordinary.

Download the reports and read them.

 

[DGM]

Where is all of the FBI evidence? How much evidence did the 9/11CR and NIST ignore?

It amazes me how much effort you skeptics have to put in to maintaining belief in the official lie. It's extraordinary.

What is the "official lie" and what is your proof? Is there an alternative theory with supporting evidence backed by the same rigor? There must bee or you would just be spinning your wheels (or a troll), where can I see this alternative theory and evidence?

 

[pgimeno]

This is laughable. NIST admits freefall, and the only thing they say is that the columns buckled. That is not an explanation, and you know it. Why did the columns buckle at exactly the same time. That requires an explanation.

Here's an explanation:

When the columns can't resist the weight above them, they all fall essentially at the same time.

You can't expect one column to fail, then 3 seconds later the next, then 3 second later the next. That's absurd. If the columns can't resist the weight, they fail.

NIST doesn't need to explain that to people who don't understand basic physics.

 

[Belz...]

Where is all of the FBI evidence? How much evidence did the 9/11CR and NIST ignore?

How about you read the reports instead of asking us?

 

[Criteria]

This is laughable. NIST admits freefall, and the only thing they say is that the columns buckled. That is not an explanation, and you know it. Why did the columns buckle at exactly the same time. That requires an explanation.

Here's an explanation:

When the columns can't resist the weight above them, they all fall essentially at the same time.

You can't expect one column to fail, then 3 seconds later the next, then 3 second later the next. That's absurd. If the columns can't resist the weight, they fail.

NIST doesn't need to explain that to people who don't understand basic physics.

3 second spacing?

How about effectively ‘no spacing’.

That is what free fall acceleration means.

 

[ozeco41]

Correct me if I'm wrong (I deleted my copies of the NIST reports a while back), but I seem to recall that NIST didn't force their FEA calculations to stop after initiation. The FEAs eventually broke down due to increasing structural failures going beyond what the software could handle.

My understanding is that we do not have the capability to come anywhere close to reliably modeling a collapse progression like what occurred in the towers or in building 7. If this is correct, it is not that NIST neglected to investigate how the buildings collapsed even though they could have done so. It's that they recognized that they could never do better than vague rough estimates (and that modeling progression was unnecessary). In other words, the investigation was as compete as was feasible.

Can anyone confirm whether this is correct?

It is correct both for the set of reasons you identify and for one other set of reasons which are often more significant.

They come from opposite ends of the spectrum of approaches to "solving the problem".

I will deliberately oversimplify to explain the point.

One end is going for more and more detail which faces two big barriers:
(a) It has historically often overloaded the available resource to do the complicated (These days FEA) calculations; AND
(b) The reality that the starting point data is not available at the level of deeper and deeper digging into detail/granulation.

Most modern generation engineers identify with FEA which has some advantages (big ones) but a few built in traps. One of them is losing sight of whether or not you have the detail.

The other "end" of the process is even more fundamental - "Is the problem properly defined?" AND "Do we have a valid starting point scenario?"

Wrong "starting point" can lead to lots of going round in circles - two of the most obvious ones on forums such as this being T Szamboti's "Missing Jolt" and the generic version of the same underlying error - "would tilt of the "Top Block" cause or prevent axial impact of dropping column ends"?

Both those are big picture errors of false starting point. The presumed and accepted by both "sides" starting scenario never existed. Both sides making or accepting a false starting point. No amount of maths or FEA wil get you out of that trap.

And there are many smaller but similar issues which arise at more detailed levels - when the starting data does not support the presumed accuracy.

So that is a simple overview - I agree with your specific points.

Have another look at your "they could never do better than vague rough estimates". Because for that one - progression - rough estimates were not "rough" at the level of detail required to solve the problem. Yes they were "rough" for the often presumed objective of putting multiple decimal points into the numbers. "Number of decimal places" is rarely the goal. And accuracy for the real goal only needs to be "sufficient for purpose or better".

A similar issue from a different perspective. I have many times posted two assertions viz
1) the rapid cascade process of Twin Towers "initiation" was led off by failure of one column for which heat was the trigger; AND
2) We will never know which column it was and we do not need to know to prove cascade mechanism.

That second assertion is not acceptable to some members - they are from the "need all the details" mind set.

 

[Dave Rogers]

3 second spacing?

How about effectively ‘no spacing’.

That is what free fall acceleration means.

Perhaps you'd like to explain further. The rest of us tend to think that free fall acceleration means that, at some point, all the columns have failed over a significant length and are not presenting any resistance to collapse. You seem to think that free fall acceleration means that a set of columns failed simultaneously, despite various observations that several of us have pointed out to you - prior collapse of the penthouses, period of increasing acceleration prior to freefall, kink in the middle of the wall, rotation to the south of the building as it fell - that makes it clear that they did not, and the fact that the building, in its period of freefall, would not contain any memory of the failure sequence in order to know how fast it should accelerate. So why, pray, do you insist that freefall acceleration means simultaneous failure?

Dave

 

[rwguinn]

99% of all FEA problems can be traced to boundary and initial conditions- said every competent analyst ever..

 

[HSienzant]

It amazes me how much effort you skeptics have to put in to maintaining belief in the official lie. It's extraordinary.

That's another example of Begging the Question.
http://www.nizkor.org/features/fallacies/begging-the-question.html

Begging the Question

Begging the Question is a fallacy in which the premises include the claim that the conclusion is true or (directly or indirectly) assume that the conclusion is true. This sort of "reasoning" typically has the following form.

1.Premises in which the truth of the conclusion is claimed or the truth of the conclusion is assumed (either directly or indirectly).
2.Claim C (the conclusion) is true.

This sort of "reasoning" is fallacious because simply assuming that the conclusion is true (directly or indirectly) in the premises does not constitute evidence for that conclusion. Obviously, simply assuming a claim is true does not serve as evidence for that claim. This is especially clear in particularly blatant cases: "X is true. The evidence for this claim is that X is true."

http://www.nizkor.org/features/fallacies/begging-the-question.html

Hank

 

[HSienzant]

This is laughable. NIST admits freefall, and the only thing they say is that the columns buckled. That is not an explanation, and you know it. Why did the columns buckle at exactly the same time. That requires an explanation.

Hello? When you remove the support, things fall down. Unless it's a cartoon, and Wily Coyote stays suspended in mid-air until he looks down and realizes he ran off a cliff.

Stop me if I'm going too fast.

When things are unsupported and things fall down, they fall at free-fall speed.

Again, stop me if I'm going too fast.

You admitted to this here:

Nothing supported the falling portion of the building during the period of freefall.

If you want to test this, jump out of a plane without a chute. Report back on your results. Did you fall at freefall speed until air resistance slowed you down to terminal velocity?

Why did the columns buckle at exactly the same time.

I am seeing another logical fallacy - a loaded question. You know what those are by now.
Or you should.

Hank

 

[FalseFlag]

Download the reports and read them.

I will gladly read the parts where NIST discusses and explains freefall.

*reads for three seconds*

Done. What else ya got?

 

[ozeco41]

99% of all FEA problems can be traced to boundary and initial conditions- said every competent analyst ever..

Yes. The problems arise when folk forget to check the "starting point".

And system/sub-system boundary issues occur across a wider range of discussion than the calculations domain of FEA.

Look at the history of me advising T Szamboti - when I have advised him of a starting point/boundary or logic problem and he responds "Where is your math or FEA"

AKA "Tony you are building the wrong house on the wrong block"

AND he responds:

"show me your hammer" OR "Show me your tool kit" OR "Can you do carpentry"

I think it sort of slightly misses the point...

... and he cannot see why.

And there is no (easy) way to get people to see their own blind spots.



(I don't have any - I look regularly and never see any....)

 

[FalseFlag]

Hello? When you remove the support, things fall down.

When things are unsupported and things fall down, they fall at free-fall speed.

Wow. We agree on something.

Yes, when you remove support things fall at freefall. Now, please show me where NIST explains why all of the columns "buckled" at exactly the same time.

I will wait (and keep waiting, because the explanation does not exist).