NASA Scientist Ryan Mackey Answers ATS Questions

reply to post by jprophet420


JP ~

The proof is in the offical report. It is up to those that do not think it is accurate to step forward with proof and say: "That is not accurate due to x,y,ad Z."

This thread is to attempt to answer question some of you may have in regards to the white paper that Mr. Mackey has posted to refute the claims of Dr. Griffin.

Dr. Griffin has had a copy of Mr. Mackey's paper for close to a month now i believe and so far has not come forth with anything showing Mr. Mackey is in error. Mr. MAckey's paper has been posted on many web sites debunking 911 conspiracies. Besides minor trivial errors (which are being kept in a journal) his paper has not been shown incorrect with his conclusion.

Mr. Mackey has also been kind enough to answer questions about the NIST report. Mr. Mackey has proven himself with his extensive knowledge and as you see, will be the first to admit if there are any mistakes he may have made.

Thanks again to all who have submitted their questions. I will be sending an E-mail off to Mr. Mackey over the next couple days.

I hope the MODs don't mind (if so please delete) I am posting a reponse I reveived from Mr. MAckey with a question I presented to him that I often hear and wanted a somewhat laymen answer. I did post this question on another thread in here becasue of the on going coversation there.

My E-mail to Mr. Mackey:

I have one question for you if you don't mind.? I often here this
argument:
>
> "The computer models stopped at collaspe initiation because of the
ridiculous variables that they had to put into the computer to start it.
> And because the collapse looked absolutely nothing like what we saw on
9/11, in that it was not symmetric and they could not get it to
> progress!!! "
>
> Would you be able to explain to me in laymen terms how I can reposnd to
this?

His response:

That argument is nonsense. The computer models stopped at collapse
initiation (and sometimes before!) because of what's called a "convergence
problem." It has nothing to do with a need for unrealistic initial
conditions or because it would give a politically incorrect answer.
NIST ran two different major structural models. These models do different
things. The one for the structure, contained in NCSTAR1-6D but also
baselined in NCSTAR1-2A is run by a program called SAP2000. The other one,
considering the dynamics of the aircraft impacts, was run in LS-DYNA.

SAP2000 is a structural model that is essentially solves the static load
problem. It cannot represent moving objects (although there may be some
workarounds, but nothing accurate on this scale). Basically the way it
works is by solving the stress-strain relationship for each element, which
is a simple equation, using a look-up table for the material properties as
a function of strain.
The reason it's difficult is because that simple stress-strain
relationship becomes an ENORMOUS matrix problem. Each piece of the
structure has several variables, representing position and strain (think
"stretch") in several dimensions. The load is a mixture of fixed boundary
conditions, like area loads on floors, and "self-weights" of the components
themselves. The elements are coupled to other elements to varying degrees.
A simple way to think about it is as follows: Start with the structure as
originally built. Then apply the load. The load creates stresses in each
component, and all of these have to balance. Once you have this, the
stresses lead to strains, and the structure sags a little bit as a result.
That changes the stress distribution, so you solve again. That changes the
strain. And so on.
At every step, you perform a calculation that is essentially a matrix
inversion. The matrices here, by the way, are incredibly large -- for the
WTC cases, they are literally bigger than a million times a million.
Matrices cannot always be inverted. If, for instance, there is a row of
all zeroes, a matrix is said to be "degenerate," and it cannot be inverted.
Inverting such a matrix is logically equivalent to dividing by zero. This
is, for instance, what would happen if you tried to include a completely
detached piece in the SAP2000 model.
In NIST's calculations, the matrices don't ever actually reach degeneracy,
they get awfully close -- an element on the diagonal that is very, very
small (i.e. close to zero) results in an "ill-posed" matrix. Inverting
this matrix is like dividing by a very small number, i.e. multiplying by a
very large number, and thus the outcome is not very stable. A small error
in this number -- even a roundoff error -- can lead to large changes in the
final result.
The more stable a structure is, and the less it deflects under load, the
easier it is to solve. As the WTC models got closer and closer to
instability, the harder it was to solve. Eventually the simulation simply
cannot proceed, due to the "convergence problem" I mentioned above. Either
the matrix inversion step gives unrealistic answers, or it results in such
a large change compared to the last step that it overshoots each time we
try to refine our result, and thus we get no single-valued answer.

This happens in real life, too. Think of a single column, near to its
buckling load, supporting a structure above. Which way will it bend?
Either way is equally energetic. As it gets closer to failure, the error
in our calculation becomes more and more significant.

Now in terms of actually modeling the collapse itself, this is much, much
worse. The situation above is still static, i.e. not moving, at least not
very fast, and we are still going to hit convergence limits. But now we
want to go even beyond that and consider a dynamic situation.
SAP2000 cannot do this. Instead, we could use a tool like LS-DYNA, which
doesn't just handle the stress-strain relationships, but also considers
kinetics -- motion, impulse, and much more focus on timestepping. Very,
very small timesteps.
We could, in theory, model the collapse in LS-DYNA. But the modeling
problem is vastly more complicated than it was before. First, we have to
decide what the actual state of the components is at the instant of
collapse, and even small uncertainties here will result in large
uncertainties in the final results. Second, we have to go through the same
process above, but now we have to do it at every timestep, so perhaps a
million times as many calculations as before. Third, we have far more
variables than before -- instead of just XYZ and the strain values for each
member, we now also have speed, adding six more degrees of freedom (three
translational and three rotational). Fourth, every time two objects
contact each other, exactly how force is transmitted is extremely sensitive
to the exact geometry. Think of all the various ways a bowling pin can
fall, and that's contact between loose, rounded objects. The variety of
objects in the WTC collapse -- shape, strength, etc. -- will be vastly
greater.
The complexity of the aircraft impact models was limited by these
performance constraints. That's why the aircraft was simplified and why
the results are open to some interpretation. Modeling the structure
collapse in similar fashion would be hundreds of times worse, or
(alternately) hundreds of times more coarse.

There's no point to doing this. What we really need is a gross-order
understanding of behavior. This is provided by models such as the one in
Bazant, Le, Benson, and Greening. Similarly, the NIST impact models don't
really care about the exact disposition of every fragment of aircraft, but
only things like the total momentum transmitted to the structure, the rough
order distribution of fuel, and the expected loads on the large core
columns. This is about the limit of detail that we can reasonably
calculate.

I've made the argument many times that dynamic models are just not that
precise. If we could accurately model the entire WTC collapses, then I
should be able to take that same model to Las Vegas, go to the craps
tables, and make a billion dollars before the bar closes. Obviously, I
can't. Even the most sophisticated models cannot accurately predict what
side of a six-sided die will come up when thrown. There is no reason to
expect billions of times higher precision from NIST.

Hope that answers your question.

Thanks,
Ryan Macke

reply to post by CaptainObvious


Another question CO, if I may.

Is it Ray's view that the towers could have been brought down by fires alone (i.e. no planes)?

I don't mean this to suggest I am exploring the no-plane theory - I'm not - I just want to know whether, even without the structural damage associated with the impacts, the towers could have been brought down by arson, let's say.

reply to post by coughymachine


Thanks coughy, I will be sending off an e-mail today or tomorrow.

Originally posted by coughymachine

Is it Ray's view that the towers could have been brought down by fires alone (i.e. no planes)?

Just my 2 cents,

Most of the reports (NIST, FEMA) state the buildings withstood the planes impacts.

The North tower had a fire in 1975 that burned for 3 hours and caused no damage to the steel.

No steel building has ever collasped from fire. Several steel buildings have had longer lasting fires and structural damage and did not collapse.

Lads, cut out the middleman.
forums.randi.org...

I would love to see someone challenging the majority over at JREF.

Originally posted by Azriphale
Lads, cut out the middleman.
forums.randi.org...

I would love to see someone challenging the majority over at JREF.

If jref was a place where we could discuss I'd go there. From what I have seen, there is nothing but viscousness toward anyone who thinks differently than the official story. How about Mr. Mackey comes here where that is not allowed?

Fair point. i think someone should invite him. Or maybe have an ATS debate.

reply to post by Azriphale


His E-mail address is on his paper. Feel free to contact him. I have stated this in the past.

Originally posted by CaptainObvious
reply to post by Azriphale

 

His E-mail address is on his paper. Feel free to contact him. I have stated this in the past.

True. We don't even need jref. But, since Mr. Mackey is and has been corresponding with you CO, I myself would like to keep it that way, so he doesn't get bogged down with hundreds of e-mails and none of our questions will get answered. Just my preference though. Anyone should feel free to contact him if they want.

I am an engineer new to ATS. Finally, I found out what JREF stands for... never before a clue. Bear with me trying to come up to speed on Mr. Mackey's report.

Can I ask- Mr. Mackey, do you believe jetliners crashed at the Pentagon and Shanksville, PA?

reply to post by jrnsr


Jrnsr ~

Mr. Mackey was taking questions from people that read his white paper to refute claims from another white paper from Dr. Griffin. I will not submit CT questions to him. He is over at the Jref forum if you wish to ask him those types of questions. Just a tip... don't go in there unless you have facts to back you up.

reply to post by Griff



Good point, I don't have a problem being the "middle man"

Just an update:

I sent off a very long winded E-mail to Mr. Mackey. I enclosed questions from many of you and hopefully will get a response.

Bsbray, I attached the links to the websites you posted along with your questions.

Thanks,

C.O.

reply to post by CaptainObvious



Thanks for keeping us up to date CO. Also thanks for being the middleman.
Good thread.

Lads, just to let ye both know that i didnt mean to cause any offense with the midleman statement/quote.

I thought ye'd be better off going directly to the man but i was wrong and ye prefer it this way. Again CO, i didnt mean to cause any offense or derail/kill the thread.

reply to post by CaptainObvious


A couple of questions about this.

1. He says that the computer models are way too complicated. Does that include the "initiation" computer models? And why wouldn't real life models be more accurate? What I mean is NIST couldn't get any of their models to collapse from fires. They could have simulated the damage from the planes. They could have even vibrated the model at it's natural frequency to see if resonance aided collapse. I would think the brilliant engineers at NIST know what resonance is and how it affects buildings?

2. He mentions "we" all throughout explaining the computer models. Does that mean that he is working alongside NIST on computer models? Or is he working on a model himself? Or through NASA? Just curious.

Originally posted by Azriphale
Lads, just to let ye both know that i didnt mean to cause any offense with the midleman statement/quote.

No offense taken on my part. Don't sweat it. I don't think CO took offense either. Plus, as it pertained to Mr. Mackey and contacting him, I don't think you were off topic at all.

reply to post by Griff


Yeah, no worries. I just recieved an E-mail and will be posting it shortly.

Thanks all for your input.

Update from Ryan Mackey:

Since the questions and responses are pretty long, each question will recieve it's own posting.


Coughymachine's questions:

What was the fuel load of Flight 175 at the time of impact as a percentage of total capacity?

If a wing 'filled with fuel, [would result] in extensive damage to the external panels of the tower, including complete failure of the exterior columns', can we assume that anything less than 100% of capacity at the time of impact would have the effect of significantly reducing the level of damage to the exterior columns upon impact?

Given the