NIST Petition Demands Corrections

[rwguinn]

TAM I'm not trying to be uncivil..believe that or not.

I felt your post was so left of centre that combined with the fact that since so many posts have passed in this thread since you last replied, I thought you were out of touch with the thread and as a result, your post was out of context.

MM

Nope--its like "General Hospital" or "One Life to Live". You can go away for a day, a week, or a month, and you haven't missed a thing.
Troofers keep running the same arguments, in defiance of all logic, physics, and common sense, hoping the science folks will give in.
A lot like politicians, in that regard, except folks who know physics and such are unlikely to cave in to mere words.

 

[Miragememories]

You are still wrong and your ideas are negligible for the over all energy model.

Your landing gear piece exiting at 105 mph has only 4 percent of the energy left meaning only about .007 or so percent of total impact energy escaped impact with the WTC for that piece.

You are busted.

How long will you not do the math?

I could just as easily say; "case closed 9/11 solved. I'm right your wrong!"

If my example is so flawed, and I am "busted', it should be very easy for you to explain to me how a pound of seat material or a pound of titanium steel striking a core column at 570 mph will have the same effect?

MM

 

[T.A.M.]

TAM I'm not trying to be uncivil..believe that or not.

I felt your post was so left of centre that combined with the fact that since so many posts have passed in this thread since you last replied, I thought you were out of touch with the thread and as a result, your post was out of context.

MM

My comment was not directed at your present discussion persay, it was directed at Arkan, and the others, and was more a comment on the motive of those who question why the less severe case was "tossed out" so to speak.

Thank you for the clarification.

TAM

 

[Newtons Bit]

Well, for starters MM, most of us will tell you titanium and steel are too different things. In general, I might trust the steel to do more damage than the titanium, as titanium (particularly after prolonged use in engines) is very brittle and may just very well shatter on impact and use it's energy in other ways.

I understand what you're trying to get at though, two objects of different materials with the same kinetic energy will cause differing levels of DAMAGE to what they impact. A better example I might provide for those who are arguing with you is:

What will cause more damage to a steel column: a super-ball toy at 500 mph, or the equivelent weight of stiff rubber?

What you're looking for is energy transfer and elasticity. When the objects entered the WTC, they bounced around (chaotically). Some of them bounced more than others. Some hit stiff columns, bounced off or were skewed about or split down the middle, carried on, and lost energy by just dragging through debris in the middle of the tower.

 

[T.A.M.]

What you're looking for is energy transfer and elasticity. When the objects entered the WTC, they bounced around (chaotically). Some of them bounced more than others. Some hit stiff columns, bounced off or were skewed about or split down the middle, carried on, and lost energy by just dragging through debris in the middle of the tower.

Including the Jet Fuel Particles, at least within the NIST computer models. I find that a little odd, that the jet fuel supposedly bounced off things, not sticking and/or soaking things such as carpet, but I guess the momentum of the fuel had something to do with this...not sure...not my field.

TAM

 

[Newtons Bit]

I'm referring to damage caused by impacting objects, not dispersal of fuel, TAM.

 

[T.A.M.]

I'm referring to damage caused by impacting objects, not dispersal of fuel, TAM.

I know, but your use of the word "bounce" reminded me of the area I just read in NISTNCSTAR1-2, concerning the computer models.

I just found it odd that they left the models allowing the fuel particles to bounce of everything, rather than having some variable that alotted a certain amount of the fuel to soak into materials within the towers etc...

TAM

 

[T.A.M.]

quote from NISTNCSTAR1-2, Page lxxxiii (page 85 of 462):

"In addition, the impact behavior of the aircraft fuel cloud did not
include the ability to stick to, or wet, interior components. Rather, the aircraft fuel SPH particles tended
to bounce off of internal structures."

TAM

 

[Newtons Bit]

I don't know of any element type in Ansys that allows for "soak" =]

The program is very complicated, but it work how most people think it does. Finite Elements is a beautiful thing, but it's only an approximation.

 

[beachnut]

I could just as easily say; "case closed 9/11 solved. I'm right your wrong!"

If my example is so flawed, and I am "busted', it should be very easy for you to explain to me how a pound of seat material or a pound of titanium steel striking a core column at 570 mph will have the same effect?

MM

Your energy is busted, you are arguing about 3.17 percent of 1 percent of all the energy in the impact and that NIST needs a better model. I am saying the problem you talk about is negligible, insignificant. You one example proves the energy we are talking about to be negligible.

I find it hard to support Dr Jones ideas, I could care less if he submits this petition, it further proves his lack of knowledge about basic physics. That is sad since he was in the physics field.

 

[T.A.M.]

So I am guessing, in general, it does not do to well with liquids.

TAM

 

[T.A.M.]

Newton:

When I was reading, I noticed they used the SAP2000 for the global models, but the LS-DYNA for the impact models.

Question: Ansys, that you mentioned above, is it a common term used within both programs, and what exactly does it stand for?

TAM

 

[beachnut]

quote from NISTNCSTAR1-2, Page lxxxiii (page 85 of 462):

TAM

My high pressure water washer, the water bounce off some stuff, but it cuts right through skin. What speed is my washer at, and I think the jet fuel would not exactly bounce off of me at 500 mph.

Did the fuel bounce off of the fire proofing, or the steel that the fire proofing was on. Does fuel act like water?

I will look up the speed of water in my pressure washer. (I have failed to find the speed the easy way)

 

[T.A.M.]

So in fact, even worse than the suggestion of soaking, rather than bounce off, it perhaps might have been a variable in the removal of the SFRM?

TAM

 

[Newtons Bit]

SAP can't be used to model a plane flying through a building. Ansys can. They both use FE (Finite Elements) as the method for analyzing indeterminate problems.

Ansys was used for the fire, I assumed it was for the impact as well.

 

[Miragememories]

How do you know? Can you show your work? I would like to understand.

Okay I'll try and explain my point as to why; 10 lbs of titanium steel and 10 lbs of wood, plastic, glass, aluminum or flesh striking a steel column at 570 mph are going to have decidedly different results!

Infracted below due to violation of Rule 4. I have removed the text and added a link; if you wish to use this as an example, you will have to repost the link and then restate the argument in your own words while using the PDF as an example.

Do not use material like this without giving credit to the author, and use links instead of text copy (even for excerpts) when appropriate.

Replying to this modbox in thread will be off topic  Posted By: jmercer

Since energy transfer is the preferred term amongst most people here, I'll use it to explain the difference in results, as in the resulting deformation damage.

Link to the PDF here.

As ∆E is proportional to the square of velocity, the more velocity the cylinder has, the more energy will be transferred into the steel column. In the simplest possible terms, if the steel column was infused with more energy than its structure could handle, it would break.

Since the titanium steel cylinder is harder and stronger than the aluminum cylinder of the same size and mass, it will create more deformation damage to the steel column.

I hope this makes sense?

MM

 

[beachnut]

Okay I'll try and explain my point as to why; 10 lbs of titanium steel and 10 lbs of wood, plastic, glass, aluminum or flesh striking a steel column at 570 mph are going to have decidedly different results!

Since energy transfer is the preferred term amongst most people here, I'll use it to explain the difference in results, as in the resulting deformation damage.

If we have a 10 pound cylinder of titanium steel and a 10 pound cylinder of aluminum, both moving at the same velocity "v", upon impact with the steel column, and ignoring the negligible amount of energy lost as thermal energy (heat), the amount of energy in the system lost to deformation damage (∆E) is given by the following:

where e is the coefficient of restitution, which measures how elastic the collision is. It is a function of the hardness or softness of the colliding objects, which along with velocity determines impulse. If hard objects collide (for a perfectly inelastic collision, e=0), they will accelerate one another quickly, transferring a large amount of force in a small amount of time while soft objects colliding (for a perfectly elastic collision, e=1) transfer smaller amounts of energy to one another for longer periods of time.

As ∆E is proportional to the square of velocity, the more velocity the cylinder has, the more energy will be transferred into the steel column. In the simplest possible terms, if the steel column was infused with more energy than its structure could handle, it would break.

Since the titanium steel cylinder is harder and stronger than the aluminum cylinder of the same size and mass, it will create more deformation damage to the steel column.

I hope this makes sense?

MM

OMG you cut and paste some junk... Now I see, Dr Jones nut case ideas on explosives is a cut and paste defense. The petition is, based on your own observations, insignificant. Where did you get that equation?

 

[R.Mackey]

I know, but your use of the word "bounce" reminded me of the area I just read in NISTNCSTAR1-2, concerning the computer models.

I just found it odd that they left the models allowing the fuel particles to bounce of everything, rather than having some variable that alotted a certain amount of the fuel to soak into materials within the towers etc...

This is another of those things that NIST had to do, since there's not much else they can do.

The fluid "bouncing" as opposed to soaking is probably accurate, since adsorption isn't usually a fast enough process to capture fluid that still has significant kinetic energy. However, the mechanism I'd expect to see is the fluid being aerosolized as kinetic energy is dissipated as heat.

Having said that, the amount of fuel was far too great to all remain in suspension -- you might think of it as there being more fuel than air in the first few seconds -- and the simulation didn't need to run for very long. These factors probably make my observation above irrelevant.

While I'll accept those simplifications, I still think NIST should have done a more thorough job matching the fuel simulation against the ultimate fuel distribution on all floors, not just the focus floors, since a great deal was dispersed all the way down into the basements. If you haven't seen it, consider the information on Table 6-1 on page 81 of NIST NCSTAR1-7 (and note to MirageMemories: I use the actual page numbers, not the Adobe Reader numbers, because it keeps references consistent, mmm'kay?). The spread of damage and fire was quite large throughout the entire structure. I don't know that their simulation doesn't account for all of the jet fuel that was sent to lower floors, but some consistency checking would be a useful additional validation.

Again, this highlights just how complex and cutting-edge this simulation is. There are lots of simplifications by necessity. In the end, we can only judge its accuracy by how well it fits observations versus how many kludges we had to invoke to get those results, and in that respect it fits rather well.

 

[R.Mackey]

Okay I'll try and explain my point as to why; 10 lbs of titanium steel and 10 lbs of wood, plastic, glass, aluminum or flesh striking a steel column at 570 mph are going to have decidedly different results!

Since energy transfer is the preferred term amongst most people here, I'll use it to explain the difference in results, as in the resulting deformation damage.

What you're missing is that you're treating impact of a single object, versus impact of a cloud of objects.

The objects in the WTC case are essentially trapped in the WTC structure (unless they actually punch a hole and exit, in which case the damage is done by default). Since they're trapped, they are doomed to deliver all of their kinetic energy to the structure, regardless of how many times it ricochets before it is finally spent.

Also, your equation is just one mechanism. Your equation predicts that jet fuel, having a coefficient of restitution of effectively one, would do no damage at all to steel columns. That is true for small amounts of jet fuel or low speeds, but it is utterly false for 10,000 gallons moving at 0.85 Mach. Indeed, in the case of the Pentagon, which didn't totally collapse and burn and therefore allowed a more detailed inspection of the impact mechanics, the primary mode of deformation is caused by blast and fluid effects, and only in a few cases was blunt impact the dominant factor.

The NIST simulations capture these effects nicely.

By the way, you have it backwards. Hard objects are more likely to collide elastically, not soft objects. That's why billiard balls aren't made of clay.

 

[Miragememories]

My numbers are based on your talk. Your work is over .07 percent energy missing. You can not even keep up with your statements and errors. You supplied the parameters and now argue in error.

It is just an energy thing. The total mass does matter too, but the pound of flesh and a pound of metal are still a pound, and the energy they have at 500 mph is still the same for KE. Until you understand this and the fact your tiny percentage energy leaving the WTC is not significant. The landing gear piece leaving is at such a low energy state because it gave up 95 percent of the energy inside the building.

Dr Jones is one of the mentally challenged liars who is behind the petition and his agenda is the only reason he has to push such a flawed petition.

Dr Jones is part of this thread topic, so Dr Jones and his flawed ideas on thermite/explosives is part of the problem with his petition. Have you lost it?

You are unable to put numbers to your ideas; WHY?

It is all about energy.

It's actually more about how energy is applied!

It's too simplistic to treat the simulation damage as simply a matter of total energy transference.

If significant amounts of energy is focused on critical structural components in each tower, energy that based on the observed data should not have been focused anywhere within the towers, then we are going to end up with a fire simulation working on non-existent tower structural damage.

Simply put, the titanium engines and landing gear, aircraft components moving at high velocity that should not have been absorbed within the tower models, had a far greater focused energy transfer potential to inflict deformation damage to the core, than did the large volume of relatively soft small particles of aluminum, glass, baggage, plastics and flesh that were moving at high velocity after the aircraft crashed through the steel outer perimeter of each tower.

The example of a pound of flesh moving at 500 mph does not equate to the same effect as the pound of steel moving at 500 mph. You are ignoring the coefficient of restitution, which measures how elastic the collision is. As I stated in an earlier reply, It is a function of the hardness or softness of the colliding objects, which along with velocity determines impulse. If hard objects collide (for a perfectly inelastic collision, e=0), they will accelerate one another quickly, transferring a large amount of force in a small amount of time while soft objects colliding (for a perfectly elastic collision, e=1) transfer smaller amounts of energy to one another for longer periods of time.

Given the need to apply an extreme case scenario to the simulation in order to create the collapse initiation, this non-existent core damage which was erroneously applied to the simulation brings the results into serious question!

MM