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

Figures & data

Figure 1. Metal and composite six-frame (half-model shown) for drop test simulation.

Table 1. Primary structural materials in aircraft models [13,18,20].

	Metal models		Composite models
Part	Material	Thickness (mm)	Material	Thickness (mm)	Element type
Cargo floor	Al-Li	3	Al-Li	3	S4R
Cargo rail	Al-Li	3	Al-Li	3	S4R
Cargo strut	Al-Li	3	Al-Li	3	S4R
A320 cargo structures	Al-2024	3			S4R
Floor spar	Al-Li	3	Al-Li	3	S4R
Floor strut	Al-Li	3	Al-Li	3	S4R
Floor track	Al-Li	3	Al-Li	3	S4R
A320 floor structures	Al-2024	3			S4R
Frame	Al-2024	3	AcF1	7	S4
Frame bracket	Al-2024	2	AcF2	3	S4
Fuselage skin	Al-2024	2	AcF1	3	S4
Stringers	Al-7075	3	AcF1	3	S4

Table 2. Primary structural materials in a mid-range civil transport [1,2,13,18,20].

Material	Density$\left(\frac{kg}{m^3}\right)$	Young's modulus(GPa)	Poisson's ratio	Yield stress(MPa)
Al-2024	2780	73.1	0.33	324
Al-7075	2810	71.7	0.32	503
Al-Li 8090	2540	77.0	0.30	370
Plexiglass	1190	3.3	0.37	33
AcF1	1580	86.4	0.32	1439
AcF2	1770	67.0	0.30	825

Figure 2. Two-frame experiment before and after impact on a rigid ground.

Figure 3. Two-frame experimental collapse test [14].

Figure 4. Six-frame model and accelerometer locations on the seat track and floor spar.

Figure 5. Acceleration from A320 drop test and comparable floor simulation from Hashemi et al. [14].

Figure 6. Portside seat accelerations, 60-Hz Butterworth, low-pass filtered.

Figure 7. Starboard seat accelerations, 60-Hz Butterworth low-pass filtered.

Figure 8. Six half-frame von Mises stress level comparison: (a) Metal, (b) quasi-isotropic composite, (c) ply-by-ply composite.

Figure 9. Six-frame (half-barrel) plasticity level comparison: (a) Metal, (b) quasi-isotropic composite, (c) ply-by-ply composite.

Figure 10. Six-frame kinetic, plastic dissipation and damage dissipation energies for each model.

Figure 11. Six-frame energy comparison between composite and metallic sections.

Table 3. Model masses.

Metal (kg)	Quasi-isotropic (kg)	Laminate (kg)
2658.7	2695.1	2695.1

Table 4. Average and measured accelerations.

	Mean acceleration		Measured acceleration
Model	Mean time (s)	Magnitude (g)	Pulse duration (s)	Magnitude (g)
Metal	0.157	4.5	0.05	22
Quasi-isotropic	0.103	6.9	0.10	18
Laminate	0.099	7.2	0.10	32

Figure 12. Acceleration comparison using Butterworth filtered signal between three material models.

Figure 13. Six-frame model Eiband plot showing the severity of impact. Redrawn from [6,22].

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