Plane Hits World Trade Center

SUBHEAD: High quality physically accurate visualization of September 11 attack on Tower One WTC in NYC.

 By Lee Ward on 21 June 2007 in - 

Image above: Still frame from structural simulation of 911 impact on Tower One WTC. from (

Researchers at Purdue University have created a state-of-the-art animation depicting the structural damage which occurred as a result of the Boeing 767 airliner crashing into the North Tower on 9/11. This animation clip is narrated with a description of what is taking place as the crash unfolds.
The simulation found that the airplane's metal skin peeled away shortly after impact and shows how the titanium jet engine shafts flew through the building like bullets.

As with an earlier simulation developed by this team that examined the 9/11 attack on the Pentagon, the World Trade Center simulation showed that it was the weight of the 10,000 gallons of fuel more than anything else that caused the damage.

"It is the weight, the kinetic energy of the fuel that causes much of the damage in these events," Hoffmann says. "If it weren't for the subsequent fire, the structural damage might be almost the same if the planes had been filled with water instead of fuel."

Mete Sozen, Purdue's Kettlehut Distinguished Professor of Structural Engineering and a principal investigator on the simulation project, says the researchers worked for years and used the best computing resources available to recreate the event.

"To estimate the serious damage to the World Trade Center core columns, we assembled a detailed numerical model of the impacting aircraft as well as a detailed numerical model of the top 20 stories of the building," Sozen says. "We then used weeks of supercomputer time over a number of years to simulate the event in many credible angles of impact of the aircraft."

Sozen says the actual damage to the building's facade that was observed was identical to the damage shown by the numerical simulation.

"We calibrated our calculations using data from experiments we had conducted to evaluate the energy imparted from fluid moving at high speed to solid targets," he says. "We concluded that the damage map we calculated for our numerical model of the building would correspond closely to the actual extent of the damage."

The simulation represented the plane and its mass as a mesh of hundreds of thousands of "finite elements," or small squares containing specific physical characteristics. In the visualization, these scientific data points are used to show how airplane components swept through the building and out through the other side as the fuel ignited.

"The aircraft moved through the building as if it were a hot and fast lava flow," Sozen says. "Consequently, much of the fireproofing insulation was ripped off the structure. Even if all of the columns and girders had survived the impact - an unlikely event - the structure would fail as the result of a buckling of the columns. The heat from an ordinary office fire would suffice to soften and weaken the unprotected steel.

Evaluation of the effects of the fire on the core column structure, with the insulation removed by the impact, showed that collapse would follow whatever the number of columns cut at the time of the impact."

Video above: Scientists simulate jet hitting world trade center. From ( 



ghpacific said...

WTC building 7 was never hit by an airplane and collapsed in pancake fashion also. Molten steel was filmed on fire in the ruins of the towers which requires heat far in excess of jet fuel burning. I attended a presentation by Richard Gage who is trying to defend the architect and engineering professions from defamation for design failures. His website is My uncle worked for Minoru Yamasaki as an architect on the WTC. The case for a pretext to invade Iraq and control its oil is not over regardless of high definition animations.

Juan Wilson said...

Aloha ghpacific,

I agree that the 911 event was the pretext for an already planned attack on Iraq. The Bush admionistration had good reason to expect an attack. It came.

I am no fan of either Yamasaki (a decorator) or the real WTC architects Skidmore, Owings, Merrill(SOM). As an architectural student I visited SOM's office during the beginning of construction and interviewed the project architect. He had spent 7 years on that job by then.

I also visited the sited during construction with my structural engineering professor and had a detailed explanation of the buildings structural theory.

The resulting building was hideous, but structurally sound. It was designed for a direct hit from a Boeing 707 (the standard large commercial jet at the time). It was not designed for a hit by something with the mass of a 757.

The ensuing fire is what warped the floor joists enough to pancake on floor onto another, thus bringing doen the building.

As for building 7... get a life. This empire is already toast.

ghpacific said...

Aloha Juan,
Thanks for the response. I'm sure you're right in not beating a dead horse. My 'life' is reading your website and others since I currently 'work' for an architect, meaning the only income I've had was a temp position for the census a year ago. Keep up the good work. Mahalo, Guy

hubie said...


who says it was steel melting on the pictures? I could also be aluminium from furniture or other stuff... else there exist pitures of wtc 7 before the crumble where you can see that a maintenance building on top of the roof is not more there, means it has already collapsed into the building BEFORE the building as a whole collapsed. This is a fingerprint of severe damage on the side towards the wtc 1 and evidence of structural integrity being hard at its limits.

Anonymous said...

Why is there no wing crumpling of any kind? Tells me its BS. No aluminum wing, especially the tip is going to slice through an 18" wide SOLID STEEL beam. Not possible in this universe, likewise the "
weakening" of the outer steel framework from the flash fire. Both buildings went straight down in free fall, not bending so much as a millimeter. Also how is it that the we see cement floor supposedly "pulverized" at the instant of collape? Because they were empty buildings with no floors. Find me one picture of a poured concrete floor between 40- 95 floor. touche

Juan Wilson said...


You gotta be kidding. That's your case. Do you believe NASA faked the moon landings too?

Juan Wilson
IB Publisher

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