WEST LAFAYETTE, Ind. — Researchers at Purdue University have created a simulation that uses scientific principles to study in detail what likely happened when a commercial airliner crashed into the World Trade Center's North Tower on Sept. 11, 2001.
The simulation could be used to better understand which elements in the building's structural core were affected, how they responded to the initial shock of the aircraft collision, and how the tower later collapsed from the ensuing fire fed by an estimated 10,000 gallons of jet fuel, said Mete Sozen, the Kettelhut Distinguished Professor of Structural Engineering in Purdue's School of Civil Engineering.
It took about 80 hours using a high-performance computer containing 16 processors to produce the first simulation, which depicts how the plane tore through several stories of the structure within a half-second, said Christoph M. Hoffmann, a professor of computer science and co-director of the Computing Research Institute at Purdue.
"This required a tremendous amount of detailed work," Hoffmann said. "We have finished the first part of the simulation showing what happened to the structure during the initial impact. In the coming months, we will explore how the structure reacted to the extreme heat from the blaze that led to the building's collapse, and we will refine the visual presentations of the simulation."
The researchers are analyzing how many columns were destroyed initially in the building's core, a spine of 47 heavy steel I-beams extending through the center of the structure, Sozen said.
"Current findings from the simulation have identified the destruction of 11 columns on the 94th floor, 10 columns on the 95th floor and nine columns on the 96th floor," he said. "This is a major insight. When you lose close to 25 percent of your columns at a given level, the building is significantly weakened and vulnerable to collapse."
The simulation research, funded by the National Science Foundation, was carried out by a team that includes Hoffmann; Sozen; Ayhan Irfanoglu, an assistant professor of civil engineering; Voicu Popescu, an assistant professor of computer science; computer science doctoral student Paul Rosen; and civil engineering doctoral students Oscar Ardila and Ingo Brachmann.