Abolhassan Astaneh-Asl
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Version vom 21. September 2010, 04:47 Uhr von Bombjack (Diskussion | Beiträge)
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Persönliche Angaben
Professor of Structural Egineering, University of California
Webseite: http://www.astaneh.net/#
Überblick
Professor Astaneh-Asl erhielt 2001 eine Förderung der National Science Foundation (NSF) um den Zusammensturz der World Trade Center Türme zu untersuchen. 2002 präsentierte er seine bis dahin vorliegenden Ergebnisse vor dem Committee on Science of the House of Representatives.
Die Präsentation vor dem Committee on Science of the U.S. House of Representatives beinhaltete folgenden versuchsaufbau:
Steel Structure Nonlinear FEA Simulation Provides Insight into World Trade Center Collapse.
Steel Structure Nonlinear FEA Simulation Provides Insight into World Trade Center Collapse.
Zitat
He was one of five expert witnesses invited to testify before the Committee on Science of the U.S. House of Representatives at the March 6, 2002 hearing. Learning from 9/11 - Understanding the Collapse of the World Trade Center. Dr. Astaneh-Asl's presentation included a movie of a simulated crash of a passenger aircraft onto a generic steel structure created with MSC.Dytran and MSC.Marc by the MSC.Software nonlinear group.
Zitat
Because of the limited time available to provide an initial analysis, a search of MSC.Software's past projects turned up the public domain geometry of a Boeing 747 with partially meshed wings and engines. MSC.Patran was used to add the fuselage and stiffeners, tail section, flooring and other major components, completing the finite element model of the Boeing 747. Concentrated masses were added in specific locations along the aircraft to represent the cargo, passenger weight distribution and fuel. The total weight of the Boeing 747 was 304,000 kg (Comment. 304,000 kg = 670,200 lb. The maximum takeoff weight of a Boeing 747 is 875,000 lb. The maximum takeoff weight of a Boeing 767 is 395,000 lb).
Zitat
A full mockup of the building was unnecessary, because of time limitations and the fact that the actual structural data had not yet been made available (Comment. Apparently, Astaneh-Asl still does not have the plans of the WTC. Wouldn't it would be reasonable to give your researchers the basic data needed for their investigations). Therefore, a generic six-story steel structure was constructed with tubular beams and columns. The gravity loading was applied to the entire structure and the dead weight of the building was added through the floorings located on the top-two and bottom-two floors of the structure. Floors were not added to the impact area, which facilitated the study of the failure pattern of both the aircraft and the beam-column connections. The foundation of the building was rigidly fixed. Approximately 61,000 elements were used to construct the entire model of the building and Boeing 747.
Zitat
The Boeing 747 was run into a centralized location of the building exterior between the 3rd and 4th floors at 200 m/sec (about 450 mph) at zero degree yaw and pitch angles. When the aircraft crashed into the WTC, the initial impact to the building resulted in massive structural failure and deterioration to both building and the aircraft. Then a fire explosion (Comment concerning the exterior fireballs. Although dramatic, these fireballs did not explode or generate a shock wave. If an explosion or detonation had occurred, the expansion of the burning gasses would have taken place in microseconds, not the 2 seconds observed. Therefore, although there were some overpressures, it is unlikely that the fireballs, being external to the buildings, would have resulted in significant structural damage.)
Zitat
As the Boeing 747 deteriorated, it dispersed approximately 10,000 gallons of fuel (Comment. This quantity of fuel is quite small considering that a Boeing 747 has a fuel capacity of 57,285 gallons.) inside the WTC, (allowing for fuel consumption during the flight). This was a massive amount of fuel and during the investigation of the WTC, fuel was even found in the elevator shafts and on the first floor. Based on the impact simulation created in MSC.Dytran, a heat transfer and thermal stress analysis was performed in MSC.Marc.
Quelle: http://www.thewebfairy.com/nerdcities/WTC/wtc-microsoft.htm
Zitate
"There are parallels between the failure of the MacArthur Maze ramps and the collapse of the World Trade Center towers," he said. "Both incidents were caused by a massive fire, fed by a large amount of fuel, weakening the steel structure." (#1)
"If you remember the Salvador Dalí paintings with the clocks that are kind of melted -- it's kind of like that. That could only happen if you get steel yellow hot or white hot -- perhaps around 2,000 degrees." (#2)
ABOLHASSAN ASTANEH: Here, it most likely reached about 1,000 to 1,500 degrees. And that is enough to collapse them, so they collapsed. So the word "melting" should not be used for girders, because there was no melting of girders. I saw melting of girders in World Trade Center.(#3)
...The witnesses to molten metal also included University of California, Berkeley engineering professor Abolhassan Astaneh-Asl, who was the first scientist given access to the steel at ground zero. Dr. Astaneh-Asl referred to the WTC steel he found as "kind of melted." Years later, when asked again about his experience he clarified, "I saw melting of girders in World Trade Center."...(#4)
Mr. Astaneh-Asl also rejects such alternative theories. "I certainly don't buy into any of the conspiracy stuff," he says. "Those are lightweight buildings," he adds. "There was no need for explosives to bring them down."(#5)
Quellen & weiterführende Links
Quellen:
- http://www.universityofcalifornia.edu/news/article/9150
- http://chronicle.com/article/Scholars-Work-to-Rebuild-the/4059
- http://www.pbs.org/newshour/bb/science/jan-june07/overpass_05-10.html
- http://www.911review.com/articles/ryan/NIST_WTC7.html#11
- http://911-engineers.blogspot.com/2007/06/berkeley-engineer-searches-for-truth.html
Interviews zum Thema: Zusammenbruch des World Trade Center
