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Posted by: Amker
« on: 26. July 2007., 22:26:12 »Researchers are still looking for answers to what pulled down the World Trade Center twin towers on September 11th, 2001, trying to impede future failures.
Now a Purdue University team came with a state-of-the-art animated visualization of the event.
"The animation reveals more information than could be conveyed through a scientific simulation alone. Our animation takes that scientific model and adds back the visual information required to make it a more effective communication tool." said Christoph Hoffmann, a professor of computer science and director of
Purdue's Rosen Center for Advanced Computing, a division of Information Technology at Purdue.
The simulation of the final test run required over 80 hours of high-performance computing. It shows the way a plane tore through several stories of the World Trade Center north tower within 0.5 seconds and reveals that the sheer weight of the flaming fuel induced a flash flood that destroyed essential structural columns within the building, ripping off fireproofing insulation from other support structures.
Voicu Popescu, an assistant professor of computer science of Romanian origin, developed a translator application that connects computer simulations to computer visualization systems, transposing simulation data into a 3-D animation scene.
"This translator is scalable and can be used in other simulations. The crashes and computer models you often see on television are not scientifically accurate. This provides an alternative that is useful to the nonexpert but is also scientifically accurate, so it provides a more realistic picture of the event." said Popescu.
The visualization starts with a Google Earth map of lower Manhattan on September 11th, 2001 and presents the damage induced by the aircraft as it hit the north tower, the way the plane disintegrated through the interior, and the airplane metal, burning fuel, dust and smoke going out of the building on the opposite side.
The airplane's metal skin appeared to peel away soon after the impact and the titanium jet engine shafts went through the building like bullets.
Like previous simulations, this one showed that the weight of the 10,000 gallons (40,000 l) of fuel were the main cause of the damage.
"It is the weight, the kinetic energy of the fuel that causes much of the damage in these events. 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." said Hoffman.
"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. 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." said Mete Sozen, Purdue's Kettlehut Distinguished Professor of Structural Engineering and a principal investigator on the simulation project
"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. 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 aircraft moved through the building as if it were a hot and fast lava flow. 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," said Sozen.
The team also aims at checking other scenarios, like an airplane inadvertently crashing into a building placed near an airport.
The animation can be seen online at
http://www.cs.purdue.edu/cgvlab/papers/popescu/popescuWTCVIS07.mov
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Now a Purdue University team came with a state-of-the-art animated visualization of the event.
"The animation reveals more information than could be conveyed through a scientific simulation alone. Our animation takes that scientific model and adds back the visual information required to make it a more effective communication tool." said Christoph Hoffmann, a professor of computer science and director of
Purdue's Rosen Center for Advanced Computing, a division of Information Technology at Purdue.
The simulation of the final test run required over 80 hours of high-performance computing. It shows the way a plane tore through several stories of the World Trade Center north tower within 0.5 seconds and reveals that the sheer weight of the flaming fuel induced a flash flood that destroyed essential structural columns within the building, ripping off fireproofing insulation from other support structures.
Voicu Popescu, an assistant professor of computer science of Romanian origin, developed a translator application that connects computer simulations to computer visualization systems, transposing simulation data into a 3-D animation scene.
"This translator is scalable and can be used in other simulations. The crashes and computer models you often see on television are not scientifically accurate. This provides an alternative that is useful to the nonexpert but is also scientifically accurate, so it provides a more realistic picture of the event." said Popescu.
The visualization starts with a Google Earth map of lower Manhattan on September 11th, 2001 and presents the damage induced by the aircraft as it hit the north tower, the way the plane disintegrated through the interior, and the airplane metal, burning fuel, dust and smoke going out of the building on the opposite side.
The airplane's metal skin appeared to peel away soon after the impact and the titanium jet engine shafts went through the building like bullets.
Like previous simulations, this one showed that the weight of the 10,000 gallons (40,000 l) of fuel were the main cause of the damage.
"It is the weight, the kinetic energy of the fuel that causes much of the damage in these events. 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." said Hoffman.
"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. 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." said Mete Sozen, Purdue's Kettlehut Distinguished Professor of Structural Engineering and a principal investigator on the simulation project
"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. 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 aircraft moved through the building as if it were a hot and fast lava flow. 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," said Sozen.
The team also aims at checking other scenarios, like an airplane inadvertently crashing into a building placed near an airport.
The animation can be seen online at
http://www.cs.purdue.edu/cgvlab/papers/popescu/popescuWTCVIS07.mov
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