Mass and Velocity of 767 vs Thickness of Trade Tower Perimeter Walls.
[I just spent a long time writing an amendment to this blog. I'm at a public terminal and lost the text i worked on. I have to go not but will re-write later tonights.
The blog entry is incorrect since my calculations were wrong. I apologize for the sloppiness.
From the Journal of Engineering Mechanics:
"Impact of the Boeing 767 Aircraft into the World Trade Center"
J. Engrg. Mech., Volume 131, Issue 10, pp. 1066-1072 (October 2005)
"A numerical simulation of the aircraft impact into the exterior columns of the World Trade Center (WTC) was done using LS-DYNA. For simplification, the fuselage was modeled as a thin-walled cylinder, the wings were modeled as box beams with a fuel pocket, and the engines were represented as rigid cylinders. The exterior columns of the WTC were represented as box beams. Actual masses, material properties and dimensions of the Boeing 767 aircraft and the exterior columns of the WTC were used in this analysis. It was found that about 46% of the initial kinetic energy of the aircraft was used to damage columns. The minimum impact velocity of the aircraft to just penetrate the exterior columns would be 130 m/s. [ i.e. 7800 miles per hour]. It was also found that a Boeing 767 traveling at top speed would not penetrate exterior columns of the WTC if the columns were thicker than 20 mm. [20mm = less than one inch thick. The columns were known to be 4 inches thick.] "
The elaborations/math work within the brackets and the graphics are mine.