The Twin Towers at free fall speed

[Newtons Bit]

Why all the resistance to a real-life test of the FEA models?

Isn't it reasonable to question whether the simulations correctly modelled their tests? What better way to verify them than to test for repeatable failure modes in a live test?

Why is this such an unreasonable standard?

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Why the speculation that it is necessary? The entire purpose of FEA was to save money (mostly because FEA is so much more accurate than standard calculations that factors of safety have been significantly lowered). Now you're advocating spending more money for what? An appeal to perfection? FEA is already close enough for reasonable people. And by close enough, I mean really really really close. It's so accurate that we use it to design new skyscrapers. And guess what, we don't test the individual elements of those skyscrapers either! Why? Because the results have already been directly confirmed by real-world experiments.

Most people here have already speculated that your appeal to perfection is based upon a deep-seated irrational (but common) need to not admit defeat. Is this really the case?

 

[A W Smith]

Why all the resistance to a real-life test of the FEA models?

Isn't it reasonable to question whether the simulations correctly modelled their tests? What better way to verify them than to test for repeatable failure modes in a live test?

Why is this such an unreasonable standard?

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http://www.cs.purdue.edu/homes/cmh/simulation/phase3/

http://www.luxinzheng.net/publications/english_WTC.htm

http://www.designnews.com/article/6471-Did_The_Building_Do_It_.php

http://www.csa.com/discoveryguides/forensic/abstracts-fcat3.php

http://www.cs.purdue.edu/cgvlab/papers/popescu/popescuITSEC08-2.pdf

how many FEA must be undertaken before you are convinced fires and impact damage caused the towers to fail? Or are you asking for a full size reproduction of the towers which we both know will never ever happen? thereby insuring your call to perfection will never be met?

 

[jay howard]

This would be accurate up to the first few seconds of the collapse, if that.

A test that replicated the results of the FEA models would suffice. I'm not suggesting building the entire structure in real life. Just see if the finite structures react the way the simulation predicts.

FACT is that you simply cannot test individual components the way you want in order to back up or refute the FEA the way you want to.

That was the whole point of NIST performing separate simulations for Global (i.e. the whole kit and kaboodle) failure, and Finite Element Analysis (i.e. individual members/joints) failures.



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[jay howard]

Why the speculation that it is necessary? The entire purpose of FEA was to save money (mostly because FEA is so much more accurate than standard calculations that factors of safety have been significantly lowered). Now you're advocating spending more money for what? An appeal to perfection? FEA is already close enough for reasonable people. And by close enough, I mean really really really close. It's so accurate that we use it to design new skyscrapers. And guess what, we don't test the individual elements of those skyscrapers either! Why? Because the results have already been directly confirmed by real-world experiments.

Because if there's controversy over the veracity of the simulations, then why not just make sure the simulations didn't overlook something? Hell, they could've used the UL floor truss tests for some of it. They were built to scale as identically as possible.

Most people here have already speculated that your appeal to perfection is based upon a deep-seated irrational (but common) need to not admit defeat. Is this really the case?

Is this where you start high-fiving each other and claiming "VICTORY!!"? Who would ever have suspected that a call for an accurate, real-world test would spark such resistance as a "skeptics" site? No me.

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[carlitos]

Because if there's controversy over the veracity of the simulations, then why not just make sure the simulations didn't overlook something?

Where is this controversy of which you speak? Why do you keep using the passive voice or "they?" Please be specific - who do you want to pay for, construct and test what exactly?

 

[A W Smith]

A test that replicated the results of the FEA models would suffice. I'm not suggesting building the entire structure in real life. Just see if the finite structures react the way the simulation predicts.



That was the whole point of NIST performing separate simulations for Global (i.e. the whole kit and kaboodle) failure, and Finite Element Analysis (i.e. individual members/joints) failures.



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And how exactly would you observe the failure of hundreds or thousands of connections buried deep within your model?

 

[carlitos]

nano-cameras built into the structure itself :/

 

[jay howard]

http://www.cs.purdue.edu/homes/cmh/simulation/phase3/

http://www.luxinzheng.net/publications/english_WTC.htm

http://www.designnews.com/article/6471-Did_The_Building_Do_It_.php

http://www.csa.com/discoveryguides/forensic/abstracts-fcat3.php

http://www.cs.purdue.edu/cgvlab/papers/popescu/popescuITSEC08-2.pdf

how many FEA must be undertaken before you are convinced fires and impact damage caused the towers to fail? Or are you asking for a full size reproduction of the towers which we both know will never ever happen? thereby insuring your call to perfection will never be met?

So you think the best way to verify a simulation is with another simulation?

Do you not understand what I'm asking or do you just think it's unnecessary because so many other people did simulations too?


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[Newtons Bit]

Because if there's controversy over the veracity of the simulations, then why not just make sure the simulations didn't overlook something? Hell, they could've used the UL floor truss tests for some of it. They were built to scale as identically as possible.

The "controversy" as you put it, is manufactured on fake-science and engineering. There is not a single paper or even idea amongst the entire truth movement that accurately calls into question any of the modelling performed by NIST.

The tests on the floor trusses at UL were stopped because a test to failure would damage or destroy portions of the lab.

Is this where you start high-fiving each other and claiming "VICTORY!!"? Who would ever have suspected that a call for an accurate, real-world test would spark such resistance as a "skeptics" site? No me.

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I'm trying to give you an opportunity to refute that claim. You seem to not want to even try.

Why do you want the "real-world" test?

Do you have evidence that NIST (as well as the other groups who created separate models and obtained similar conclusions) manufactured results? Do you have evidence that FEA is wrong and cannot be correlated to reality? An answer of "no" to both of these questions shows that you're just trying to waste everyone's time and money in coming up with a ridiculous standard of perfection.

 

[jay howard]

Again, there's an unusual amount of protestation about a call for a real-life test. Some people protest that "It's too expensive!"
Others claim "It's all been accounted for by other simulations..."
Some say "It's too complicated to run a real-world test on."
While others say "All the tests have already been run."

Get your excuses straight.

Not a single person says "sure, that's not a bad idea. Why not just take the FEA models and see if a real test looks like the simulation."

Seriously, what possible harm would come to anyone to verify the simulations with a real world test?


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[jay howard]

The "controversy" as you put it, is manufactured on fake-science and engineering. There is not a single paper or even idea amongst the entire truth movement that accurately calls into question any of the modelling performed by NIST.

The tests on the floor trusses at UL were stopped because a test to failure would damage or destroy portions of the lab.



I'm trying to give you an opportunity to refute that claim. You seem to not want to even try.

Why do you want the "real-world" test?

Do you have evidence that NIST (as well as the other groups who created separate models and obtained similar conclusions) manufactured results? Do you have evidence that FEA is wrong and cannot be correlated to reality? An answer of "no" to both of these questions shows that you're just trying to waste everyone's time and money in coming up with a ridiculous standard of perfection.

If you think this is a waste of time, then by all means, go spend your time elsewhere.

 

[A W Smith]

So you think the best way to verify a simulation analysis is with another simulation analysis?

Do you not understand what I'm asking or do you just think it's unnecessary because so many other people did simulations analysis too?

I have taken the liberty to edit your quote to remove the weasel wording. And now can more accurately respond by saying, Yes, it is unnecessary to build a model to verify a FEA.

 

[Newtons Bit]

If you think this is a waste of time, then by all means, go spend your time elsewhere.

If you think the real-world test is necessary, please go spend YOUR money on it. Do not ask me to spend my money (i.e. tax dollars) on it while people in this country are still without the basic necessities of life.

 

[beachnut]

If you think this is a waste of time, then by all means, go spend your time elsewhere.

You do not understand the real world event is a full up test with not only a model, but the actual building. You can't understand 911 so you want a real life test; oops, u missed it twice, 2 times for Balsamo, on 911.

You fail to understand the goal of NIST and seem to prefer full blown nut case delusions made up by idiots in 911 truth, a failed movement; 8 years of failure.

What do you have on the free fall nonsense as you drift off topic into displaying a complete lack of knowledge in engineering, models, and more?

 

[carlitos]

Seriously, what possible harm would come to anyone to verify the simulations with a real world test?


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None. For like the 50th time, what is stopping you from testing things?

 

[Newtons Bit]

Again, there's an unusual amount of protestation about a call for a real-life test. Some people protest that "It's too expensive!"
Others claim "It's all been accounted for by other simulations..."
Some say "It's too complicated to run a real-world test on."
While others say "All the tests have already been run."

Get your excuses straight.

Those are all valid and correct reasons. Which logical fallacy is this? False dilemma?

 

[Reactor drone]

Again, there's an unusual amount of protestation about a call for a real-life test. Some people protest that "It's too expensive!"
Others claim "It's all been accounted for by other simulations..."
Some say "It's too complicated to run a real-world test on."
While others say "All the tests have already been run."

Get your excuses straight.

Not a single person says "sure, that's not a bad idea. Why not just take the FEA models and see if a real test looks like the simulation."

Seriously, what possible harm would come to anyone to verify the simulations with a real world test?


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While I don't think it's necessary to verify the FEA analyses with a "real world" test I certainly wouldn't try to stop anyone from building a 25 storey replica of the upper section of the WTC and then rocketing a full size 767 into it to see how it performs.I'm fairly confident it will do what the actual twin towers did and what all the FEA analyses show but if you and other like minded individuals think differently the by all means go ahead.

You could probably get some of the initial outlay back by showing the results in some kind of pay per view venue.

 

[JimBenArm]

What's keeping him from doing it?
Nothing, except he thinks the grown-ups need to do it for him, he's got no idea what he really wants (which is why he won't say it explicitly), and he lacks the knowledge and expertise to do it himself, so of course we have to do it for him, in spite of the fact he doesn't know what it is he wants done!
Understand? Good. Get to it!

 

[tsig]

Again, I don't think it's controversial to say that in a complex system like the crash site of the towers, there can be all kinds of factors that the model designers may be leaving out or over-or underestimating. That's why a particular principle should be tested, i.e.: "steel girders with k static force from x,y directions and t temp over m time will result in these failure modes f and j."

They do those tests on girders before they build the building. That's how they know it will stay up.

 

[tsig]

Oh jesus, stop whining. I'm saying if the computer simulations demonstrate failure of certain connections at certain temps over a specified time, then that info should be translatable to a real-life test.

Now, it should probably be scaled to a reasonable size, but the results should be repeatable in real life, don't you agree?

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How do you scale gravity?