Abstract
ニューヨーク世界貿易センタービルのテロ事件では，飛行機が衝突した際に，瞬間的に発生した引張力が床スラブの結合部を損傷し，構造物を進行性崩壊に早く至らしめた可能性がある．そこで本報告では，骨組構造体の衝突崩壊問題に対して有効な解析手法として開発されたASI-Gauss法を，ニューヨーク世界貿易センタービル2号棟の飛行機衝突解析に適用し，この影響を調べた．その結果，飛行機が衝突した瞬間に衝撃波が伝播し，設計段階では想定していない特異な応力状態に構造物がさらされていた状況が判明した．また，ボーイング767の右エンジンが貫通する箇所および速度，被害状況などが観測データと良好に一致することが確認された．
In this paper, the previously developed ASI-Gauss technique is applied to an aircraft impact analysis of New York World Trade Center Tower 2 (WTC2), to evaluate the structural vulnerability and behavior of the aircraft, at the horrifying scene that occurred in 2001. The ASI-Gauss technique is a modified version of the formerly developed Adaptively Shifted Integration (ASI) technique for the linear Timoshenko beam element, which computes highly accurate elasto-plastic solutions even with the minimum number of elements per member. The ASI-Gauss technique gains still higher accuracy especially in elastic range, by placing the numerical integration points of the two consecutive elements forming an elastically deformed member in such a way that stresses and strains are evaluated at the Gaussian integration points of the two-element member. From the numerical results, propagation of the shock waves resulted from the impact and high-level stresses in the structural members were observed. We could also see how the main wings of the aircraft cut through the perimeter columns and spandrels, how the debris moved through the building and to where it caused damages. Moreover, the velocity reduction of the right engine and the location from where it moved out of the building were in good agreement with the observed data.