Solid Bodies versus Rubble: Results

[DaveThomasNMSR]

Tony makes excuses, color me shocked.

I am curious why Tony wanted the 2-to-5-pound drop test at all, since he seems content with using much smaller weights now. Or, will the goalposts simply be moved again if I do another experiment? Just sayin'.

 

[ozeco41]

I am curious why Tony wanted the 2-to-5-pound drop test at all, since he seems content with using much smaller weights now. Or, will the goalposts simply be moved again if I do another experiment? Just sayin'.

The underlying phyiscs is easy to comprehend. ( It is at about graduate level to explain qualitatively - quantitatively is a bit harder.) However Tony's objective and specification of the problem and the challenge to you is IMO too vague.

But the real need is to decide whether or not he wants it to model something which is relevant to the actual WTC collapses. The abstract model is not perfect in itself. There is no point in perfecting the experimental test if:
1) It is intended to demonstrate something about WTC collapse; AND
2) It doesn't do that OR there are better ways.

It is his challenge - let him say what he is trying to show. It is partly there in the record of posts.

 

[DGM]

The underlying phyiscs is easy to comprehend. ( It is at about graduate level to explain qualitatively - quantitatively is a bit harder.) However Tony's objective and specification of the problem and the challenge to you is IMO too vague.

But the real need is to decide whether or not he wants it to model something which is relevant to the actual WTC collapses. The abstract model is not perfect in itself. There is no point in perfecting the experimental test if:
1) It is intended to demonstrate something about WTC collapse; AND
2) It doesn't do that OR there are better ways.

It is his challenge - let him say what he is trying to show. It is partly there in the record of posts.

The problem here is, Tony's abstract is presented in theory but argued as reality. He has a serious problem separating the two in concept.

 

[ozeco41]

The problem here is, Tony's abstract is presented in theory but argued as reality. He has a serious problem separating the two in concept.

Spot on!

It is one of the persistent problems with his claims/papers. Look at the thread discussing "his" new paper. Look at "Missing Jolt" etc etc. All suffer from the same fatal error. He does not separate abstract models from reality and the evidence is strong that he cannot do so. He certainly declines to acknowledge the problem. Routinely runs away or insults me when I point him at the error. And, naturally, it invalidates any claim that he falsely bases on that lack of separation.

 

[femr2]

Use the original scale and don't change anything but the bag restraint on the rice.

The Balance Board is a very effective Force Plate, ideally suited for this experiment.

If you change the scale, drop height, or anything else, your results will not be valid, since there will be differences in the response that there would not have been in a direct comparison.

Nonsense, so long as both solid and loose masses using the same equipment. Results from using a Balance Board will be far, far superior to those from a kitchen scale, which still (the kitchen scale) has all manner of damping and latency issues.

Your "argument"...

Take a 5 lb. bag of sugar or 2 lb. box of rice and put some sides around a scale with ounce graduations with at least a 10 lb capacity, and pour the sugar or rice from the same height as what Dave Thomas dropped his bag of rice from. I'll bet you don't see much more than 5 lbs. for the sugar or 2 lbs. for the rice if any at all.

...was proven false before you even said it. Basic physics.

If you want to place one grain of rice carefully on the scale every second, then you would have a point. Otherwise...lol.

Rate of "flow" does of course make a difference, but I'm afraid dictating a flow rate so low as to "prove your point" is a cop-out.

In "reality" the descending portions of the Towers were not grains of rice, but instead pretty huge interconnected and mangled sections.

I might see how much lego I can find, make some tower sections out of it, and drop a sack of such on a WBB. (Depends how much Lego I can find )

 

[femr2]

I'm also looking at trying out the Wii balance board test Femr2 has suggested.

A good plan. Absolutely ideal for this experiment.

I'll probably be doing this myself in the near future.

As there is no significant motion (the WBB has four independant force and accelerometers with near-zero travel) the mechanical damping and momentum effects are negligible.

That also means that filming is pretty redundant, as there is no visible "response" of the equipment.

100Hz data rate should be enough to provide a good force/time profile (and derivatives), especially as there will be four independant and simultaneous datasets.

 

[jaydeehess]

Might you shrink-wrap the rice and suck the air out of it to make it more solid? Like a brick of rice? There is still going to be some looseness in a bag of rice. Not sure if this would be significant, and if the "brick" doesn't hit flush, there would be deflection issues... Just thinking out loud.

Since only the first response of the scale is the most relevant to the force delivered, it would make little difference if it did not land flat. It would however, as you say this would better reflect the limit of solid block.

 

[jaydeehess]

Dave has the right idea with the double trap door. In fact in order to further remove door effect the doors would be powered open rather than simple trap door which requires that some of the potential energy be converted into energy to swing the doors open.

In order to reduce boundary effects of the container(friction at the sides that slows some of the rice) you could make the container pyramidal , pointy end up.

Of course we are no longer 'pouring' rice as TS suggested but then if that direction were taken literally onecould 'pour' a single grain every 0.1 sec and never see the scale reflect a dynamic force at all, only the gradual response to the increasing static force due to the mass of the rice building up.

Hey, here's another thought. Why not substitute 3/4 inch steel hex nuts instead of rice.

If this has any rrelevance to the WTC collapses then the loose piece size should somewhat reflect the model scale of reality. I am pretty sure that the rubblizing tower's average steel rubble piece size was not at the scale of rice grains to block of rice.

 

[jaydeehess]

The Balance Board is a very effective Force Plate, ideally suited for this experiment.


Nonsense, so long as both solid and loose masses using the same equipment. Results from using a Balance Board will be far, far superior to those from a kitchen scale, which still (the kitchen scale) has all manner of damping and latency issues.

Your "argument"...

...was proven false before you even said it. Basic physics.

If you want to place one grain of rice carefully on the scale every second, then you would have a point. Otherwise...lol.

Balance board, very good idea. Reduces spring constant effects to inconsequential.

I see that I posted a similar thought as your last one above after you did.

There are quite a few variables that could be examined for their effect on the force on the platform.
Height of drop
Platform spring and damping effects(including inertial effects of moving the platform which is where the grain per second may show no dynamic force)
Average distance between loose pieces
Mass per loose piece(ie. Sugar grain, rice grain, 3/4 inch nut)
Initial velocity in H&V of loose pieces(pouring from an inclined plane, friction of container sides, trap door effect)

All in all it can be designed as an interesting physics or engineering experiment.
It can illustrate the effects of various variables in a dynamic situation.
How one then manages to quantify how it relates to the collapses of the WTC structures would be quite a challenge.

 

[jaydeehess]

Here's another though.....

How about you first use a box full of 3/4 inch nuts. As the 'solid mass'. Then, to model loose pieces you stack the nuts up in one or two towers and drop them? Want to model the effect of changing average distance between pieces? Tie the nuts together in a string with 1 cm separation. Hang the string then let it loose all at once. Try again with 2 cm separation.

( might have relevance to WTC since the rubble was from varying heights)

 

[femr2]

will the goalposts simply be moved again if I do another experiment?

If your results don't support Tony's "viewpoint", then more than likely.

He really should think things through before he types.

Just like when he backed himself into a corner on his latest "collaboration" and ended up inventing his "24 outer core column removal, causing all perimeters to pull in and fail" theory.

1) The core would have to descend many feet to cause the required pull-in by the mechanism described. That scale of core descent would have to occur before the perimeters failed.

2) Video evidance proves there was no such perimeter behaviour, nor was there any apparent significant vertical core motion prior to perimeter unzipping.

Total nonsense, even if one wanted to "believe in it".

 

[femr2]

Balance board, very good idea. Reduces spring constant effects to inconsequential.

Indeed.

As I posted a week or two ago, the WBB has been lab tested against professional force plates costing upwards of $18000 with very positive results...

When doctors disassembled the board, they found the accelerometers and strain gauges to be of "excellent" quality. "I was shocked given the price: it was an extremely impressive strain gauge set-up," said lead researcher Ross Clark, in an interview with New Scientist.

Even better, Clark's team has already published a paper that verifies the Wii balance board is "clinically comparable" to the nearly $18,000 lab force platform.

A comparison with Kistler force plate 9287CA...

There are quite a few variables that could be examined for their effect on the force on the platform.

For sure.

All in all it can be designed as an interesting physics or engineering experiment.

Yes. Experiment. Not WTC model. Getting Tony to understand the difference should be a laugh.

It can illustrate the effects of various variables in a dynamic situation.

Yes. 100Hz data rate with four simultaneous datasets should be enough to produce pretty good force/time profiles, including variation in Center Of Mass.

How one then manages to quantify how it relates to the collapses of the WTC structures would be quite a challenge.

Once the setup is complete, I'm sure a range of tests can be performed.

 

[Miragememories]

"The problem here is, Tony's abstract is presented in theory but argued as reality.

He has a serious problem separating the two in concept."

For you maybe.

Theory is proven by reality.

MM

 

[ozeco41]

...Yes. Experiment. Not WTC model. Getting Tony to understand the difference should be a laugh....

We don't have a good record at getting Tony to understand the difference between models and real events.

 

[DGM]

For you maybe.

Theory is proven by reality.

MM

Context of the word "abstract" is sort of important here.

 

[femr2]

The outer diameter of the scale is 38.2 cm.

The fame rate was 1000 frames per second.

That results in the following velocity profile...

Would have been good to have a longer clip, so that the recovery of the scale could be captured (which I expect to be a decaying oscillation).

Obviously can't generate a force/time graph, as mass is not a constant, which is where the WBB will come in most handy....and in the same breath highlights the benefit of a 1000fps camera...hmm.

ETA: You said "I estimate the clip for loose rice was 675 frames, so about 0.675 seconds.". The clip from YT has 289 frames.

Could you check what timebase your YT video actuall has ? (As in the actual amount of time each frame in the YT video represents)

 

[DaveThomasNMSR]

That results in the following velocity profile...

[qimg]http://femr2.ucoz.com/_ph/9/870409151.png[/qimg]

Would have been good to have a longer clip, so that the recovery of the scale could be captured (which I expect to be a decaying oscillation).

Obviously can't generate a force/time graph, as mass is not a constant, which is where the WBB will come in most handy....and in the same breath highlights the benefit of a 1000fps camera...hmm.

I can generate a longer clip from the raw CINE file. Getting to it is the problem - there are two classes, a newsletter and a band practice all standing in the way... But I'll try to by the end of the week.

Dafve

 

[femr2]

I can generate a longer clip from the raw CINE file. Getting to it is the problem - there are two classes, a newsletter and a band practice all standing in the way... But I'll try to by the end of the week.

Dave

Cool. I'll be looking at the WBB soon, so there's zero rush...and the data may become redundant...so don't go to too mush bother

 

[jaydeehess]

Indeed.

As I posted a week or two ago, the WBB has been lab tested against professional force plates costing upwards of $18000 with very positive results...



A comparison with Kistler force plate 9287CA...

[qimg]http://femr2.ucoz.com/_ph/9/2/208143945.jpg[/qimg]

Proves the point that anything purchased by millions of households will make it cheaper per unit than if only a few labs purchase it.How do I get millions of households to purchase one of these http://harrisbroadcast.com/product...hers/SmallRouting/PanaceaCleanQuietSwitch.asp to bring the price down from $8K?

Yes. Experiment. Not WTC model. Getting Tony to understand the difference should be a laugh.


Once the setup is complete, I'm sure a range of tests can be performed.

Apparently the same problem will exist with MirgaeMemories.

Indeed the problem with TS and MM seems to be the unqualified ( as in no qualifiers used in the statement) that loose material results in less force than a solid block.
As stated above, I have no problem with that as a statement of basic physics. Transfer of momentum over a longer time period, will result in a lower max force. The issue is whether or not this would result in a difference in collapsing the floors of the WTC.
To use an analogy in my world one can say that an increase in input voltage will cause protection circuits to take effect (ie, a fuse will blow). Yes, this is true BUT in the real world the input voltage must rise enough to cause an increase in current above the rated value of the fuse/protection circuit and remain there long enough for the fuse or protection circuit to blow/detect the raised value. For many circuits, a transient of a few nanoseconds will not do anything whereas a few tens of milliseconds will. The qualifier is the quantification of the transient and the specs of the device.
However we see absolutely no backing experimentation or research done by TS or AE911T to quantify this in regards to the effects of all the variables that would affect the max force delivered to the floor as a whole.

It is the 'not enough heat from the 7WTC fires to buckle a girder' argument. For years AE911T has called upon NIST to relinquish their input data set for 7WTC so that they (AE911T) can 'verify' the results. Using NIST data would do what? It would allow AE911T to plug this data into the exact same fire sim program and see if running it gives the results NIST published.
THAT'S research? NO, that's an assumption of malfeasance. What AE911T has had a decade to do is to research and document what they feel should be the input data set, then run a the same fire sim program NIST used and perhaps separate program as well and compare results.
THEN they can argue that NIST 'should have' done this or that.

It all simply illustrates the very lazy attitude that AE911T has wrt to actually doing anything.
IMHO of course.

 

[jaydeehess]

For you maybe.

Theory is proven by reality.

MM

What theory?
Proven by what event in reality?
When was this done?

Driving my car at high speeds for an extended period of time will cause damage to the vehicle.
True!
BUT
ONLY IF one qualifies what 'high speed' and 'extended time' means. After all I can take my car at 60 MPH on a modern highway and drive for several hours. That is both high speed and extended time period but well within the specs for the vehicle to withstand. There are other variables to take into consideration as well though. Altitude, ambient temperature and humidity, road condition for instance. Too high and there is an extra strain on the engine, temp above 40C and there is extra strain on the engine and braking system, temp below -40C and same applies, dirt road versus newly paved......

Even in the two original variables stated in the premise, if 'high speed' means 100 MPH or greater, and/ or 'extended time' means 12 hours then even at 17C at 30M above S.L. and on a newly paved road, the vehicle will be damaged.

Using this analogy perhaps you can see that the bald statement of physics means little when trying to attribute the statement to have any meaning whatsoever wrt to the collapse of a WTC tower.

ETA: I should also mention that I drive a Chevy Cruze, not a NASCAR race car.