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Ursprungligen postat av
Gosif
Det är inte alls förvirrande det jag skriver, det som gör mig förvirrad är hur ett plan kan åka in i ett torn som en hand genom ett handfat med vatten... Som om det försvann in i byggnaden. Det ser så fejk ut. Finns inte ett enda annat exempel där samma sak sker med ett plan som åker in i en byggnad eller liknande.
Det finns förstås folk som har räknat på detta (inte KlokOchSnygg då men folk som kan räkna):
Karim, M. and Fatt, M. (2005). ”Impact of the Boeing 767 Aircraft into the World Trade Center.” Journal of Engineering Mechanics, Volume 131, Issue 10, Pages 1066–1072, 10.1061/(ASCE)0733-9399(2005)131:10(1066).
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"When the aircraft impacts the building at the top speed (240m/s) with a full fuel tank and the exterior columns have the original column thickness of 9.5mm., it is observed that all columns fail and the aircraft penetrates through the exterior wall. 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 130m/s. 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 20mm."
Omika, Y., Fukuzawa, E., Koshika, N., Morikawa, H., and Fukuda, R. (2005). ”Structural Responses of World Trade Center under Aircraft Attacks.” Journal of Structural Engineering, Vol. 131, No. 1, Pages 6–15, 10.1061/(ASCE)0733-9445(2005)131:1(6).
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"Based on the results of the analysis using a detailed finite element model, the damage situation of each structural component around impacted stories and the destroyed components were evaluated. As a result, the damage situation of the outer wall of WTC1 and WTC2 and the velocity reduction curve of the aircraft for WTC2 showed good agreement with the actual phenomena."
Wierzbicki, T., Xue, L., and Hendry-Brogan, M. (2002). "Aircraft Impact Damage", The Towers Lost and Beyond - A collection of essays on the WTC by researchers at theMassachusetts Institute of Technology, Ed. Eduardo Kausel, pages 31-63.
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It was found that the momentum transfer between the airframe and the first barrier of external columns was responsible for most of the energy dissipated in this phase. The energy to shear off the column constituted only a small fraction of that energy.