Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New simulation shows 9/11 plane crash with scientific detail

11.09.2002


Engineers, computer scientists and graphics technology experts at Purdue University have created the first publicly available simulation that uses scientific principles to study in detail what theoretically happened when the Boeing 757 crashed into the Pentagon last Sept. 11.


This image was taken from a simulation, believed to be the first of its kind, that merges a realistic-looking visualization with a precise, physics-based animation that shows what likely happened to the Pentagon’s steel-reinforced concrete structure when it was hit by the Boeing 757 last Sept. 11. The simulation, created by a team of engineers, computer scientists and graphics technology experts at Purdue University, could be used as a tool for designing critical buildings – such as hospitals or fire stations – to withstand terrorist attacks. This image shows a representation of the aircraft just before impact. (Departments of Computer Sciences and Computer Graphics Technology, Purdue University)


This image, showing a representation of the aircraft shortly after impact, is another realistic-looking graphic from the same simulation. The simulation shows what likely happened to the Pentagon’s steel-reinforced concrete structure when it was hit by the Boeing 757 last Sept. 11. (Departments of Computer Sciences and Computer Graphics Technology, Purdue University)



Researchers said the simulation could be used as a tool for designing critical buildings – such as hospitals and fire stations – to withstand terrorist attacks.

The simulation merges a realistic-looking visualization of the airliner approaching the building with a technical, science-based animation of the plane crashing into the structure.


"This is going to be a tremendous asset," said Mete Sozen, Purdue’s Kettelhut Distinguished Professor of Structural Engineering. "Eventually, I hope this will be expanded into a model that we can use to help design structures to resist severe impact loads.

"Using this simulation I can do the so-called ’what-if’ study, testing hypothetical scenarios before actually building a structure."

The simulation can be recorded on a DVD and played on an ordinary personal computer.

The software tool is unusual because it uses principles of physics to simulate how a plane’s huge mass of fuel and cargo impacts a building. The plane’s structure caused relatively little damage, and the explosion and fire that resulted from the crash also are not likely to have been dominant factors in the disaster, Sozen said.

The model indicates the most critical effects were from the mass moving at high velocity.

"At that speed, the plane itself is like a sausage skin," Sozen said. "It doesn’t have much strength and virtually crumbles on impact."

But the combined mass of everything inside the plane – particularly the large amount of fuel onboard – can be likened to a huge river crashing into the building.

The simulation deals specifically with steel-reinforced concrete buildings, as opposed to skyscrapers like the World Trade Center’s twin towers, in which structural steel provided the required strength and stiffness. Reinforced concrete is inherently fire resistant, unlike structural steel, which is vulnerable to fire and must undergo special fireproofing.

"Because the structural skeleton of the Pentagon had a high level of toughness, it was able to absorb much of the kinetic energy from the impact," said Christoph M. Hoffmann, a professor in the Department of Computer Sciences and at Purdue’s Computing Research Institute.

Sozen created a mathematical model of reinforced concrete columns. The model was then used as a starting point to produce the simulation.

Hoffmann turned Sozen’s model into the simulation by representing the plane and its mass as a mesh of hundreds of thousands of "finite elements," or small squares containing specific physical characteristics.

"What we do is simulate the physics of phenomena and then we visualize what we have calculated from scientific principles as a plausible explanation of what really happened," Hoffmann said. "We hope that through such simulations we can learn from this tragic event how to protect better the lives of our citizens and the civil infrastructure of the nation."

The simulation may be the first of its kind for merging realistic-looking animation with scientifically rigorous computations.

"Most of the computer-simulated crashes you see in movies or on TV are not realistic from the point of view of physics," said Voicu Popescu, an assistant professor of computer science. "They are designed to be spectacular rather than realistic. What hasn’t been done much, or, to our knowledge hasn’t been done at all, is to create a visualization that looks realistic in the sense that you would recognize the Pentagon and the plane and is, at the same time, true to physics."

The mesh of finite elements in the model require that millions of calculations be solved for every second of simulation. Creating only one-tenth of a second of simulation took about 95 hours of computation time on a supercomputer. Researchers originally used a bank of computers and later worked closely with Purdue’s information technology staff to harness IBM supercomputers at Purdue and Indiana University.

"The majority of the work had to do with producing the right models and then setting up the particular mesh so that we could work out accurately how this scenario unfolded," Hoffmann said.

In the simulation, the plane crashes into the building’s concrete support columns, which were reinforced with steel bars. In this simulation the columns were assumed to be "spirally reinforced," a technique popular in the 1940s in which steel bars were wound around columns in a helical shape. The coiled steel provided added strength to the columns and probably is responsible for saving many lives, Sozen said.

The simulation might be especially useful for engineers who are trying to design reinforced concrete structures that better withstand terrorist attacks or accidents involving aircraft crashes.

"Our focus was on modeling the impact effect of the liquid fuel in the tanks of the aircraft – the amount of energy transferred to the building’s structural load-carrying system, which is mainly the reinforced concrete columns, and the condition of those columns after the impact," said Sami Kilic, a civil engineering research associate who specializes in earthquake engineering.

A major challenge has been learning how to combine commercially available software with the special models needed to simulate an airliner hitting a building, Kilic said.

The Purdue team used commercial software that is normally used by auto manufacturers to simulate car crashes. But adapting the software to simulate the plane crash and then combining the realistic-looking graphics with scientific simulation has been especially difficult, Kilic said.

"Integrating these two animations is uncommon," he said. "We are discovering a new territory. We had some interaction with aeronautical engineers, and they had never heard of this kind of a simulation, with an aircraft hitting a building.

"This kind of a structure/aircraft interaction is not done commercially."

Writer: Emil Venere, (765) 494-4709, venere@purdue.edu

Sources: Mete Sozen, (765) 494-2187, sozen@purdue.edu

Christoph M. Hoffmann, (765) 494-6185, cmh@cs.purdue.edu

Voicu Popescu, (765) 496-7347, popescu@cs.purdue.edu

Sami Kilic, (765) 496-6657, skilic@purdue.edu

Purdue News Service: (765) 494-2096; purduenews@purdue.edu

Emil Venere | EurekAlert!

More articles from Interdisciplinary Research:

nachricht Easier Diagnosis of Esophageal Cancer
06.03.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Sandia uses confined nanoparticles to improve hydrogen storage materials performance
27.02.2017 | DOE/Sandia National Laboratories

All articles from Interdisciplinary Research >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>