Development of a finite element model for comparing metal and composite fuselage section drop testing

Abstract

Part of the work of AircraftFire, a project investigating the effects of fire and crash on aircraft survivability, is presented. This work compares the effect of changing the material model from metallic to composite on the impact damage and floor acceleration characteristics. First, the metallic two-and six-frame sections of an A320 are analysed, with drop test data to compare for reference and validation. The six-frame metallic and composite sections for a larger, A350-like aircraft are examined to compare the relative safety of newer composite fuselages. The composite model includes both a quasi-isotropic analysis with damage based on maximum allowable strain, and a ply-by-ply laminate model with Hashin damage. Energy dissipation and acceleration analyses follow, which show the potentially dangerous acceleration pulses for passengers seated in the cabin.

Crash simulation of fuselage section in the rebound process and the secondary-impact process

“…The distance between the fuselage frames is 482.6 mm, and the angle between the strut and the cabin floor is 105.6°. Detailed component data and materials of the fuselage section are provided in Table 1 (Gransden and Alderliesten, 2017;Liu et al, 2013).…”

“…Al2024 is used as the material of skin and the cabin floor, other fuselage components including the frames, while the struts are made of Al7075. Both Al-2024 and Al-7075 have isotropic elastic and plastic properties defined in Table 2 (Gransden and Alderliesten, 2017;Liu et al, 2013).…”

“…The drop test of the fuselage section is the most effective, but the most expensive approach to evaluate crashworthiness. Vertical drop tests have been conducted in large, expensive and full-scale testing campaigns for the past aircraft generations, such as Airbus A320, Boeing 707, Boeing 737 and NAMC YS-11, to investigate their crash performance (Gransden and Alderliesten, 2017;Hashemi and Walton, 2000;Logue et al, 1995;Abramowitz et al, 2000;Vaughan and Alfaro-Bou, 1979). NASA performed crash tests of small general aviation planes to examine the effects of pitch angles, roll angles and impact velocities (Castle and Alfaro-Bou, 1979;Alfaro-Bou and Vaughan, 1977).…”

Experimental and Numerical Crashworthiness Study of a Full-Scale Composite Fuselage Section

“…In 1995, researchers of the Centre d'Essais Aeronautiques de Toulouse executed an A320 fuselage section vertical drop test [27] and Gransden and Alderliesten [28] developed an FE model for comparing metal and composite fuselage section drop testing, finding how acceleration peaks increased using composite material with consequent necessity to improve the understanding of composite frames' behavior under crash loads.…”

Optimisation of thin-walled hybrid vertical struts for crashworthy aircraft designs

“…As for the inner reinforcement, many materials and designs have been explored over the last years, including cork compounds [21,22], wood [23], fibre-reinforced polymers (FRPs) [24,25], metals [26], and foams of various natures [27][28][29]. The usage of these has gained importance in the aircraft industry, where they are now used in primary and secondary structures due to the high strength to weight ratios [30][31][32]. When the struts are filled, the ductile collapse process of the outer tube is modified so as to obtain a stable crushing [33,34] which, in turn, is achieved by obtaining a higher number of ordered folds, which yields a smoother mechanical response and higher energy absorption values [35].…”