Next Generation Composite Aircraft Fuselage Materials under Post-crash Fire Conditions

Abstract

This paper summarizes a series of small-scale tests carried out to evaluate and model the post-crash fire integrity of composite aircraft fuselage structures.The US Federal Aviation Administration regulations for the penetration of an external fuel fire into an aircraft cabin after crash require a burn-through period of 4 min (FAA § 25.856 Appendix F, Part VII). Different candidate structures for the next generation of composite aircraft fuselage, provided by Airbus, were investigated, including CFRP monolithic laminate and a folded-core CFRP sandwich. Those materials were subjected to constant heat flux from a propane gas burner, while being held under compressive load in a small, specially designed compression test rig with anti-buckling guides. The propane burner was calibrated to produce a constant heat flux up to 182 kW/m 2 . The sample time-to-failure was measured, along with the temperatures at various points through the thickness.Modelling the thermal and structural behaviour under load required the use of a modified version of the Henderson Equation, which describes heat transfer through composites under ablative fire conditions. This has been incorporated into the Com-Fire software model. Kinetic parameters for the resin decomposition reaction were determined from thermo-gravimetric data and other thermal parameters, conductivity and diffusivity were measured experimentally. The paper will compare the behaviour of single and double-skinned structures and will examine measured and modelled behaviour.

Measuring method for thermal conductivity of a pyrolysis layer

“…Over the last decade, a few researchers have explored this problem. For example, thermal diffusivity, measured as a function of temperature from 15 o C to 50 o C, is taken to calculate the bondline temperature of the carbon fiber reinforced epoxy resins during pyrolysis [25], but the measured parameter is not thermal diffusivity of the pyrolysis layer. Bourbigot et al [26] measured the thermal conductivity of intumescent coatings using hot disc equipment…”

Study of the influence of low air pressures on fire behavior and burn‐through of aircraft cargo liner

“…Marker et al 5 conducted full‐scale tests with a reusable fuselage test rig to evaluate the fuselage burn‐through resistance of transport‐category aircraft exposed to large postcrash fuel fires. La Delfa et al 6 evaluated and modeled the postcrash fire burn‐through resistance and structural integrity of composite aircraft fuselage structures under various compressive loads. Tran K.D.…”

Intermediate-scale Fire Performance of Composite Panels under Varying Loads

“…Less is found for materials that are pre-stressed. Included in this sub-category is Feih et al (2008Feih et al ( , 2008a Bai and Keller (2009), Boyd et al (2007Boyd et al ( , 2007a, Burns et al (2010) Kwon et al (2006) La Delfa et al (2009), Liu and Holmes (2007), and Liu et al (2011). Liu et al (2011) examined compressively stressed composites under a thermal environment (60-260ºC) with experimental testing.…”

“…Sorathia et al (1993) did thermal post-test stress analysis. Of all the above, Cao et al (2009), Burns et al (2010), Kwon et al (2006), La Delfa et al (2009), Liu et al (2011) and Sorathia (1993) evaluated composites with carbon fibers of varying types. Kawai et al, (2001Kawai et al, ( , 2009 also examined carbon fiber epoxy materials, but they were unidirectional layers not rotated in the matrix, but rotated on the structural rig.…”

“…Indeed, much of the material science literature (not all cited here) is focused on finding additives to enhance charring of the binder to reduce volatile emissions and retain strength. Feih et al (2008), La Delfa et al (2009), Liu et al (2011), and Lua (2011) looked at sandwich materials.…”