NON-STRUCTURAL MASS MODELING IN AIRCRAFT IMPACT ANALYSIS

摘要

The current paper presents an investigation of the effects on a generic reinforced concrete containment structure subjected to impact by a large commercial aircraft, whereas different modelling approaches for the non-structural mass are applied. The straightforward approach for modelling of the non-structural mass of the aircraft (e.g. fuel and payload) is to include it as additional density to the corresponding structural elements. This approach, which is referred to as 'rigid mass modelling' would lead to conservative results in case of impact analysis as the non-structural mass remains attached to the aircraft for the entire duration of the calculation, resulting in an overestimation of the impact effects. An alternative approach for modelling of the non-structural mass is the application of the Smooth Particle Hydrodynamics (SPH) method. For the purposes of the current study, two models of the aircraft B777-300ER are created - one with the non-structural mass considered as additional mass density and another one, with the non-structural mass modelled with SPH particles. The crushing pattern of the plane corresponding to the two models is compared by impact simulation into a rigid wall. Additionally, the influence of the non-structural mass model on the structural capacity of a generic reinforced concrete containment is investigated. The damage effects, in terms of perforation area and displacement at the impact location, are compared; fragilities for perforation scenarios are presented, too. As a conclusion, it is shown that the 'rigid mass modelling' seems more conservative than the realistic SPH model of nonstructural mass although the latter may require significant computational effort.