Physical Impact Model Video

[psikeyhackr]

I mostly try to focus on the impossibility of an airliner causing what happened to the WTC. But I have looked over those pictures of the cars and am forced to admit that nothing I know of could produce those effects.

So we end up with people talking about nukes and the "impossibility" of wiring the building which I'm not sure is impossible. And ignoring tons of debris hurled 600 feet into the AmEx Tower. FEMA has an X on the map for it but doesn't tell us what it weighed. It had to be at least 80 tons.

So whatever the truth is, it is lost in the confusion and bullshit.

psik

[dMole]

Agreed, the "inverse square" law doesn't jive with the auto and truck destruction, and the only 2 explanations that have been offered are taboo subjects apparently. That is a LOT of heat a LONG way from the burning Towers, no doubt. Maybe all that indestructo-paper blowing around somehow transferred that heat to the police cars, ambulances, and fire trucks and blew out the nearby windows... or not.

How about 2 Solid State Cockpit Voice Recorders (SSCVR) and 2 Solid State Flight Data Recorders (SSFDR) that are data-survival rated for 3400G impacts and 1100 degrees C for 60 minutes ALL being vaporized on the same morning by two 1G building collapses?

I'm glad physics doesn't work like that on THIS side of the Rockies...

[psikeyhackr]

I just had a peculiar thought yesterday. It is related to the computation of the heat energy necessary to weaken the steel. It is discussed on this page:

http://911research.wtc7.net/mirrors/...tc/how-hot.htm

The airliner added more than 100 tons to the mass of the building, mostly aluminum. The fire can't tell what is part of the building and what isn't so the wreckage of the plane would absorb heat also. But energy absorbed by the wreckage would not weaken the building so the energy and temperature calculations would have to include a heat sink that big.

I don't recall seeing any mention of this in six years.

psik

[dMole]

That's a very good point. "Thermal mass" is a concept understood by few, and a Boeing transport airliner will bring a LOT of it to the party. Have you ever sat on aluminum football stadium bleachers in early winter? For simplicity's sake let's just call it aluminum mass * the specific heat of aluminum (in applicable units). Let's subtract out the engine masses, since they have very little aluminum and are quite hot already.

From my records, AA11 was reported to be:
B767-223ER #N334AA Boeing# 22332, GE CF6-80A2, Mode 3A 1443 off 08:20:38 EDT

From GE:
http://www.geae.com/engines/commerci.../cf6-80c2.html

Fan/Compressor Stages: 1F/3LPC/14HPC
Low-Pressure Turbine/High-Pressure Turbine Stages: 5/2
Max Diameter (Inches): 106
Length (Inches): 168

Dry Weight (Lb.): 9,480 - 9,860

Okay, let's average the engine at 9670 lbs. 2 of these are 19,340 lbs. Let's not be morbid and consider the passenger specifics, but the Jet A thermal mass also should be considered in a better estimate.

From:
http://www.airliners.net/info/stats.main?id=103

767-200ER - Empty with PW4056s 76,566kg (168,800lb), with CF680C2B4s 76,476kg (168,600lb), operating empty with PW4056s 84,415kg (186,100lb), with CF680C2B4Fs 84,370kg (186,000lb). Max takeoff with PW4056s or CF680C2B4Fs 175,540kg (387,000lb).

From:
http://www.janes.com/aerospace/civil...eing_767.shtml

"Structure
Fail-safe structure. Conventional aluminium structure augmented by graphite ailerons, spoilers, elevators, rudder and floor panels; advanced aluminium alloy keel beam chords and wing skins; composites engine cowlings, wing/fuselage fairing and rear wing panels; CFRP landing gear doors; and aramid flaps and engine pylon fairings.
Subcontractors include Boeing Military Aircraft (wing fixed leading-edges); Northrop Grumman (wing centre-section and adjacent lower fuselage section; fuselage bulkheads); Vought Aircraft (horizontal tail); Canadair (rear fuselage); Alenia (wing control surfaces, flaps and leading-edge slats, wingtips, elevators, fin and rudder, nose radome); Fuji (wing/body fairings and main landing gear doors); Kawasaki (forward and centre fuselage; exit hatches; wing in-spar ribs); Mitsubishi (rear fuselage body panels and rear fuselage doors). "

All right, fuel will come out of the maximum takeoff weight- let's ignore it though. If we take off 2 engines 186,000 - 19,340 = 166,660 lbs. Let's assume 80% of this figure is aluminum, since most of those other aerospace materials are quite light and most of the structure is aluminum. This gives 133, 328 lbs of aluminum for AA11/North Tower WTC1.

From
http://hyperphysics.phy-astr.gsu.edu...les/sphtt.html

Specific heat of aluminum (c_Al) = 0.215 BTU/lb * deg_F = 0.900 J/g*K = 24.3 J/mol*K

So, the thermal mass would be 133,328 lb * 0.215 BTU/lb * deg_F = 28665.52 BTU/deg_F. Now thermal coupling is fairly tricky business, but as you pointed out, aluminum is used extensively for its "heat sink" properties. The NIST FAQ #7 claims a maximum air temp of 1800 F, but let's use the melting point of aluminum instead here.

http://www.chemicalelements.com/elements/al.html
Melting Point: 660.37 °C (933.52 K, 1220.666 °F)

Okay, let's assume we heat the thermal mass above from 70F to 1221 F, or +1151 deg_F. 28665.52 BTU/deg_F * 1151 deg_F = 32994013.52 BTU = 3.30E7 BTU to melt AA11. That's 33 million BTU's of heat for just AA11.
------
My records for UA175 show:
B767-222 #N612UA Boeing # 21873, PW JT9D-7R4D, Mode 3A 1470 > 3020 > 3321

I don't really like Wikipedia, but they came up first for the JT9's:
http://en.wikipedia.org/wiki/Pratt_%26_Whitney_JT9D

JT9D-7R4D/D1
8905 lb, 132.7 in long, 93.4 in diameter fan, 48 000 lbf Static Thrust

From the page above:
http://www.airliners.net/info/stats.main?id=103

" 767-200 - Empty with JT9Ds 74,752kg (164,800lb), with CF6s 74,344kg (163,900lb). Operating empty with JT9Ds 80,920kg (178,400lb), with CF6s 80,510kg (177,500lb). Max takeoff 136,078kg (300,000lb), medium range max takeoff 142,881kg (315,000lb)."

178,400 - (2 * 8905) = 160,590 lb. Again assuming 80% Al, this gives 128,472 lbs of aluminum.

128,472 lb * 0.215 BTU/lb * deg_F = 27621.48 BTU/deg_F for UA175/WTC2 South.

27621.48 BTU/deg_F * +1151 deg_F = 31792323.48 BTU = 3.20E7 BTU to melt UA175. That's 32 million BTU's. I think psik and now I are the first to even look at these considerable heat sinks that I'm aware of.
-------------------------------------
But wait, there was WATER in those buildings for sprinklers and restrooms, etc. I even recall hearing of water tanks to maintain pressure. Now I think nearly everyone knows that automobile engines usually use water for cooling, although they may not be aware of its extremely high specific heat capacity.

From:
http://www.sciencebyjones.com/specific_heat1.htm

Relative to aluminum, water has a specific heat capacity of 1.00/0.217 = 4.6082949309 times.

Relative to steel:
http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/Thermal/HeatCapTable.html

1.00/0.108 = 9.2592592593 times higher for water than steel.

Looking at aluminum's thermal conductivity,
http://hyperphysics.phy-astr.gsu.edu...les/thrcn.html

it is 205.0/50.2 or 4.0836653386 times that of steel. Relative to concrete, 205.0/0.8 =256.25 times. It is 205.0/0.6 or 341.6666666667 times that of water at 20 deg_C.

Okay, for the laymen out there, this says the majority of the heat will likely flow to aluminum first (and melt it if hot enough), then steel, then concrete, then water.

Even the NIST FAQ says:
http://wtc.nist.gov/pubs/factsheets/faqs_8_2006.htm
"8. We know that the sprinkler systems were activated because survivors reported water in the stairwells. If the sprinklers were working, how could there be a 'raging inferno' in the WTC towers?

Both the NIST calculations and interviews with survivors and firefighters indicated that the aircraft impacts severed the water pipes that carried the water to the sprinkler systems. The sprinklers were not operating on the principal fire floors.

However, there were ample sources of the water in the stairwells. The water pipes ran vertically within the stairwells. Moreover, there would have been copious water from the broken restroom supply lines and from the water tanks that supplied the initial water for the sprinklers. Thus, it is not surprising that evacuating occupants encountered a lot of water.

..."

Now while the water is much less thermally conductive, I don't think that the incredible thermal mass of an unknown "bath" of water can be ignored in a proper accounting of WTC heat sinks. I haven't even mentioned the high heat of vaporization of water, but I think anyone who has boiled a pan of water knows what I'm getting at here.

There is also some interesting info about water and fuel tanks over at:
http://www.whatreallyhappened.com/fema_report.html

d
------------------------------------------
EDIT: Well this was interesting- haven't seen it before...

http://www.epa.gov/oig/reports/2003/...pn20010916.htm

Supplemental Appendices
Report No. 2003-P-00012

* This document was reproduced to maintain Accessibility requirements as outlined by Section 508. If you would like to obtain a printed version of this document please contact the OIG's Office of Congressional and Public Liaison at (202) 566-2391.
PUBLIC NOTICE

September 16, 2001
CONTACT: (718/337-4357)

Notice to Building Owners Located South of 14th Street, Manhattan

Building Maintenance Issues Involved in Reopening Buildings Closed Since 9/11/01

Air Circulation Systems: Building owners are advised that air circulation systems not operated since Tuesday must have their filters replaced before the system is restarted. Systems should be run on a recirculated air setting and not on fresh air, if possible, until the WTC fire is extinguished.

Asbestos or other Hazardous Materials situations: Owners/managers should have possible contamination problems, indoors or at roofs, reviewed by competent professionals (i.e., R.A.s, P.E.s, Asbestos Inspectors, etc.) prior to beginning clean-up of buildings with maintenance personnel. Where no problems are noted, proceed with clean-up. Where problems (i.e., HazMat) are noted, contact DEP as indicated below.

All issues regarding air asbestos and/or hazardous material clean-up should be directed to the Department of Environmental Protection's complaint center at 1-718 DEP-HELP (337-4357). Help center operators will refer your call to Asbestos and Hazardous Materials staff from 8:00 a.m. to 8:00 p.m. every day including weekends until such time as the Mayor's office declares the emergency over. Staff will review each case individually on the telephone and verbally approve clean-up activities--paperwork to follow. Emergency situations which arise outside of these time frames will be handled by help center staff taking down the caller's name and contact phone number and notifying personnel on stand-by who will then contact the caller directly.

Open Water tanks: Building owners are advised that water tanks not operated since Tuesday must be completely drained from the cellar, flushed, cleaned, refilled and plumbing systems flushed before having the building reoccupied. You should contact the water tank cleaner who normally performs this yearly operation for you to arrange for this cleaning, if possible.

All other water pressure, sewage, noise and air quality complaints should be directed to 1-718-DEP-HELP.

[AuGmENTor]

Da?

[dMole]

Thanks Aug. You made me notice that I hadn't finished my homework. To actually MELT the aluminum into the liquid phase, I'd need the heat of fusion figured in too.

http://www.engineeringtoolbox.com/fu...ls-d_1266.html

Lists the heat of fusion for aluminum as 398 kJ/kg, or about 171.11 BTU/lb. For UA175, the "smaller" of the two calculations above, this adds 22 million BTU's, for a total of 54 million BTU's needed to melt the aluminum UA175 "heat sink." A BTU is the amount of heat needed to raise 1 lb of water 1 deg_F.

In other words, 54 million BTU's would heat 1,080,000 lbs (or approx. 135,000 gallons) of water +50 deg_F.

[psikeyhackr]

ROFLMAO

dMole you are a trip.

It just gasses me how the NCSTAR1 report is full of so much trivia and they don't mention so much stuff likely to be important. They said one plane had 5 tons of cargo and the other had 9. Don't forget to put that in your calculations. LOL

But I did a search on "center of gravity" and it was not there. Then I searched on "center of mass" and found 4 mentions. Now I was thinking about the center of mass of the top portion of the building that supposedly crushed everything below. I was wondering how they could explain it staying centerd and not falling off the side. But they only talked about the "center of mass" of the plane in one report on the effect of the impact on suspended ceilings.

The whole building collapsed because of suspended ceilings. LOL

psik

[psikeyhackr]

It's been close to a year since I payed attention to this but they did use "center of gravity" six times. But they weren't talking about real objects from 9/11.

The NIST NCSTAR1 report can be extremely amusing at times if you can stomach it. One of the most astounding events of 9/11 was the top of the south tower tilting before coming down and disappearing in a dense cloud of dust. So I figured any discussion of that occurence had to refer to either the "center of mass" or "center of gravity" of at least 25 stories of the building. So I searched my DVD download of the report to see what turned up. Definitely not what I expected.

Center of mass is only used 4 times and the only real object it references is the airplane. It appears that they were extremely concerned about ceiling tiles and devoted an entire report to them. The only Interesting thing about it that I can tell is that the plane decelerated at 60 g's and came to a stop in 0.63 seconds. Suspended ceilings must be of major concern in the collapse of a 500.000 ton building.


NCSTAR 1-5D Ceilings.doc (offset 34)
http://wtc.nist.gov/NISTNCSTAR1-5D.pdf
Reaction of Ceiling Tile Systems to Shocks

center of mass page 77(*3)

Some of the airplane debris would not likely have traveled this far into the tower, while some parts of the plane and some of the fuel passed through the building and exited the far side. It was, therefore, assumed that the center of mass of the airplane penetrated slightly more than one-half of the tower’s depth. Assuming that the center of mass of the airplane is located at approximately the center of its length, the center of mass of the airplane would have traveled approximately 197 ft (60 m) between when the nose impacted the face of the tower and when the airplane remnants came to rest.

center of mass page 79

where, x p (t ) was the position of the center of mass of the airplane at time t. Given the initial and final velocities of the airplane and the differential displacement, described above, Equations 2–3 and 2–4 were solved to determine the acceleration parameters. The estimated peak acceleration of the airplane was found to be –62g (–610 m/s2), and the estimated duration of the impact was found to be 0.63 s. The resulting acceleration history is shown in Fig. 2–45.

They don't use the term "center of gravity" in relation to any real physical object at the WTC. They only use it in explaining how they configured their simulation software in specifying columns for the simulator. I find this truly amazing for a 11,305 page report that took 3 years. I guess the centers of mass and gravity don't matter for the tons of material that was hurled hundreds of feet from the buildings.

NCSTAR 1-6.doc (offset 82)
http://wtc.nist.gov/NISTNCSTAR1-6.pdf
Structural Fire Response and Probable Collapse Sequence of the
World Trade Center Towers

center of gravity page 182

Shell elements were used to model the plates comprising the box column and the spandrels. Rigid elements connected the center of gravity of the column to its component plates and the spandrel at both the top and the bottom of the model. The column was simply supported in three directions at the bottom and simply supported in the horizontal directions at the top. Increments of axial displacement were applied at the top of the model.

center of gravity p186

In the ANSYS panel model, beam elements replaced shell elements to model the columns, while shell elements were used to model the spandrels, and beam elements attached the center of gravity of the columns to the mid-plane of its corresponding spandrel component at each shell element through the depth of the spandrel.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - -

NCSTAR 1-6C.doc (offset 48)
http://wtc.nist.gov/NISTNCSTAR1-6C.pdf
Component, Connection, and Subsystem Structural Analysis

center of gravity page 44

Four-node finite strain shell elements were used to model the plates of the column and the spandrels. Nodes of column plates at the top and the bottom of the model were rigidly tied to the center of gravity of the column cross section. The column was pinned at the bottom and fixed in the two horizontal directions at the top. Increments of axial displacement were applied at the top of the model at room temperature and 700 ̊C.

center of gravity page 216

The model also represented Column 151 from Floor 96 to Floor 97 since the dimensions, plate thicknesses, and material properties were identical to those of Column 151 from Floor 95 to 96. SHELL181 plate elements modeled the plates of columns and spandrels. CERIG rigid elements connected the center of gravity of the column to its component plates and to the spandrel at both the top and the bottom of the model. The column was pinned at the bottom and restrained in the two horizontal directions at the top. Axial displacement was applied incrementally at the top of the model.

center of gravity page 222

To capture the gravity load effects from upper floors (those above Floor 99), internal forces and moments at midheight of the columns between Floors 99 and 100 in the LERA SAP2000 global model, caused by dead plus 25 percent of design live load, were applied as loads at the tops of the corresponding columns in the exterior wall model at the center of gravity of the columns. To capture the gravity load effects from individual floors, floor loads were extracted from the LERA SAP2000 floor model and applied to each column.

center of gravity page 222

For columns that were modeled by BEAM189 elements, temperatures were provided for nodes at the center of gravity of the column, and their linear gradients transverse to the exterior wall were also provided. Gradients parallel to the wall were found to be negligible. Temperatures for SHELL181 elements were provided at each node. NIST did not always provide temperatures for the bolts at column splices. When bolt temperatures were provided, they matched temperatures at the nearest interior or exterior tips of columns.

All of the page numbers refer to the PDF pages, not the official NIST page numbers. Doing searches in Adobe shows the PDF numbers. I specified the offset for each report for the pedantic among us. Just subtract the offset from the PDF page to get the official government sanctioned, approved and certified page number.

Since for some reason the government locked this PDF document, even though taxpayers payed for it, it is impossible to cut and paste from it with Adobe. But never fear, I am much to lazy to have typed the info and was able to cut and paste from it with the Linux software, Evince.

psik

[psikeyhackr]

The 9/11 Truth Movement has gotten extremely complicated and confusing with all of the different perspectives and interpretations of vast amounts of data resulting from the bizarre events of that day. Some of which is neither correct nor important, so inevitably a lot of people dismiss the movement as a bunch of kooks which, unfortunately, some of them are.

So I propose a little thought experiment to simplify things a bit.

Imagine that we have WTC2, the south tower, intact as it was on Sept 10, 2001. Since the plane impacted at the 81st level of the building let's completely remove FIVE LEVELS of the building, 79, 80, 81, 82 and 83. Since each level of the building was 12 feet in height this would leave a 60 foot gap between the top of the 78th level and the bottom of the 84th.

Now that is far more damage than the airliner could possibly do. It eliminates any debate about how hot the fires were and whether they could weaken the steel. Obviously there is not point in discussing fake planes.

The formula for distance from acceleration and time is:

d = 1/2 a t^2

Since gravitational acceleration is 32 ft per seconds squared the data for this problem yields:

60 = 16 * t^2

Therefore the time is about 2 seconds.

1.936491673 sec = t

So the intact upper 27 levels would take 2 seconds to fall and impact the intact lower 78 levels. The formula for velocity from acceleration and time is:

v = a * t

Which for these values yields:

64 ft/sec = 32 ft/sec^2 * 2 sec = 44 mph

Since each level of the World Trade Center was 12 feet the top of the 78th level was:

78 levels * 12 ft/level = 936 ft

Now if the falling 27 stories could maintain a constant velocity from the moment of impact until it reached the ground it is easy to compute how long that would take.

936 ft / 64 ft/sec = 14.625 seconds

If the bottom 78 floors prevent the top from accelerating but crumple at a constant velocity it would take 15 seconds to crush 78 floors. Since the building came down in 11 seconds the top had to crush the bottom and accelerate at the same time. A truly amazing feat.

Are we supposed to believe those 78 level would not cause the falling mass to SLOW DOWN?

What is going to happen the instant the instant the bottom of the 84th level comes in contact with the top of the 78th? They are going to engage in a mutual crushing of steel, concrete and office furniture that would be deadly to behold. But where is the energy to do that crushing going to come from? It is going to come from the kinetic energy of the falling mass. Which means the falling mass is going to SLOW DOWN. It is going to DECELERATE. It is going to undergo NEGATIVE ACCELERATION. Which means it must take longer than 15 seconds to reach the bottom, if it ever does.

But to come up with anything vaguely resembling an accurate analysis of this simplified thought experiment we would have to know the TONS of STEEL and TONS of CONCRETE on every level of the WTC. The expected and maximum loads for each level would probably help too. That would tell us how over-engineered the building was and the extra energy necessary to crush it. Since the people who designed the World Trade Center way back in the 60's, when computers still had CORE MEMORY, it is certainly amazing that our EXPERTS don't even raise such childishly simple questions in these days of laptop supercomputers. The NIST report mentions that total amount of steel in the towers three times but NEVER SPECIFIES the total amount of concrete though it says two types of concrete were were used.

Some people accuse the "conspiracy theorists" of not understanding the difference between static loading and dynamic loading as though the difference is going to cause the overloaded material to burst into dust. But we are dealing with a material state with inputs applied and a known output of a TOTALLY DEMOLISHED BUILDING. The known input is a 150 ton plane with 34 tons of kerosene traveling at 500+ mph. How can we claim to know the state of the material if we don't know the TONS of STEEL and TONS of CONCRETE on every level. The believers in the official story demand proof of an energy input besides the plane but don't demand accurate information about the subject of the destruction. You can't do an analysis if you don't know what you are analyzing.

Of course we can trust Dr. Sunder of the NIST when he says the buildings came down so fast because they were 70% air. It is incredible that the nation that put men on the moon will tolerate crap like that.

http://www.pbs.org/wgbh/nova/wtc/cons-flash.html

So until we can get such simple information as the TONS of STEEL and TONS of CONCRETE on every level then talking about fake planes, beam weapons and nuclear devices is absurd because we really don't understand what it was that was destroyed.

psik

[psikeyhackr]

Dr Sunder of the NIST tells us that the World Trade Centers came down so fast because they were 70% air by volume.

http://www.pbs.org/wgbh/nova/wtc/cons-flash.html

Notice he specifies "by volume." So how much was that by weight? We often hear the each tower was 500,000 TONS. How many TONS of air were in the building?

1 cubic foot of air at standard temperature and pressure assuming average composition weighs approximately 0.0807 lbs.

These were the dimensions of the WTC

207 ft. * 207 ft. * 1360 ft. = 58,274,640 cu. ft. above ground volume of WTC

So that volume of air weighed:

58,274,640 * 0.0807 = 4,702,763.448 lbs. of air

Which came to:

4,702,763.448 lbs. of air / 2,000 lb/ton = 2,351.381724 tons of air

2,351.381724 tons of air / 110 levels = 21.38 tons of air per level

But obviously Dr. Sunder is saying that 30% of the building was not air.

21.38 tons of air per level * 70% = 14.96 30% loss due to presence of building

So there were approximately 15 tons of air on each level of the WTC but the NIST cannot tell us the TONS of STEEL and TONS of CONCRETE that were on each level of a building designed in the 1960s and stood for 28 years. They can't do that with 3 years of research and $20,000,000 but they can tell us it came down so fast because it was 70% air by volume. Well it was only 0.5% air by weight and it wasn't the air that held it up for 28 years.

On average the towers had 862 tons of steel on each level and he is saying they came down so fast because of 15 tons of air per level.

Dr. Sunder should be laughed all of the way back to India for saying something that ridiculous.

psik