Computed damage to the core structure of the World Trade Center North Tower, 0.37 seconds after impact. Image courtesy of Mete Sozen, Ayhan Irfanoglu and Christoph Hoffmann

The Northwest Indiana Computational Grid and Purdue’s Network for Computational Nanotechnology have provided the infrastructure support for large-scale simulations of the effects of crashing an air frame loaded with fuel—similar to a Boeing 767-200ER—into a steel and concrete structure—similar to that of the World Trade Center North Tower.

Results from the simulations are being used to understand the extent of the damage caused by the impact.

The modeled airframe is loaded with the approximate amount of fuel and set to impact the WTC-1 building at the speed, position and orientation published in official reports.

The simulation models both the exterior building skeleton and the core support structure of the building, as well as concrete floors and supporting girders.

The simulation uses adaptive time stepping, which averages to approximately 0.000001 second time steps. Snapshots of the simulation are generated approximately every 0.0025 seconds.

The airplane arrives with an initial velocity of 470 miles per hour, with penetration to the core structure of the building occurring in approximately 0.1 seconds.

A critical issue in defining the damage was modeling the fuel in the aircraft: in this case about 27% of the aircraft’s mass was provided by fuel.

This project was supported in part by a National Science Foundation Information Technology Research grant.