JEC COMPOSITES MAGAZINE - Issue #106 - July 2016 - 40

CFRP

New technology for
hybrid carbon-fibre fuselage

By
YOSIF GOLFMAN
FOUNDER
NEO-ADVENT TECHNOLOGIES LLC

arbon fibre cannot mitigate the potentially damaging electromagnetic
effects of a lightning strike. To solve
this problem, an electrically conductive
expanded metal foil (EMF) can be added
to the composite structural lay-up to
rapidly dissipate the excess current and
heat, protecting the CFRP materials in an
aircraft from lightning [1].
As Japanese researchers discovered,
coating carbon fibre with an elastomer can
reduce the vibration and acoustic effects.
The damping loss factor ranges from
0.01 to 0.100, thus improving vibration
properties [2].
A thermoforming technology was developed for multifunctional layers. In shipboard and aircraft applications, a spraying
technology can be more effective. A concept for epoxy spraying for toughness on

The innovative Boeing 787 Dreamliner consists of more than
50% carbon fibre reinforced plastic (CFRP), a material that combines low weight and exceptional strength. Using COMSOL tools,
engineers at Boeing Research found that a metal foil inserted in
an CFRP package can provide lightning protection for the aircraft
structure. The purpose of the work described in this article is to
improve this package, using a lattice mesh netting reinforcement
as a supporting structure and a thermoplastic skin to create
multifunctional materials that protect the fuselage from lightning
strikes while providing vibration damping and sound absorption
properties.

the bottom layer and polyester spraying
for sound absorption on the top layer is
an interesting alternative to the open-cell
polyimide foam insulation panels developed for NASA [3]. Traditional insulation
materials - 3/8" EAR and Pyrotech 3/8"
SP150 tiles - are described in [4] and [5].

Technology development
A CFRP fuselage with a polyester-based
damping protection showed that an epoxy
adhesive layer can work together with a
polyester layer, with an insulation thickness up to 127 mm [6].
The damping effect of the Neo-Advent insulation appears in the frequencies below
500 Hz. The damping loss factors of the
Neo-Advent material are significantly lower at frequencies below 500 Hz, compared
to the traditional insulation materials,
1/8"-3/8" EAR and 3/8" Pyrotek SP
150. The minimum coefficients of sound
absorption are in the 125-300 Hz range

40 jec composites magazine / No106 July 2016

of frequencies, and the maximum in the
1000-4000 Hz range [6]. For large aviation
parts, the traditional infusion/vacuum
process is more suitable, and less expensive than braiding technology.
The Boeing 787 was designed to be the
first composite-based production airliner,
with the fuselage assembled from onepiece composite barrel sections instead
of the multiple aluminium sheets and
approximately 50,000 fasteners used in existing aircraft [7, 8]. The braided preform
production line uses a quasi-continuous
process to produce A-350 ring frame
preforms from dry carbon fibre, which are
subsequently resin infused [9]. However,
more automation was used in the extrusion process when using a mesh netting
shell to reinforce the fuselage.
The top skin of the fuselage uses a polyester-based damping protection and the
bottom of the fuselage is made from a

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #106 - July 2016