JEC COMPOSITES MAGAZINE - Issue #81 - May/June 2013 - 9

of fibres could also turn out
to be an advantage for lightning protection. There are
also a lot of futuristic material
options out there which you
don’t see on today’s aircraft,
but which could be an option on the next generation
single-aisle. At GKN, we have
moved into automation in
composite lay-up for higher
lay-up rate solutions (Figure
5). We have a lot of good
composite analysis technique and data and looking
at the different processes for
actually curing composites.
GKN’s composite expertise
places it as one of the leading
companies worldwide.
GKN’s focus on both composites and metals gives us a
balanced approach, as for all
major aerospace players.
JCM: Do you sell patents for
technologies you have developed?

C.G.: No. Within GKN we

have four divisions: Land
Systems, Drive Line, Powder
Systems & Metallurgy, and
Aerospace. Between us, we
work the technology across
the four divisions. For example, we are trying to help the
automotive side in their efforts to use more composites
in their components, and they
help us in additive manufacturing materials. n
More information:
www.gkn.com/aerospace

Complex composite wing structure
using new manufacture and assembly processes

ne of the latest
process technology
achievement of GKN
Aerospace is its programme
on out of autoclave processes and new joining
technologies.
GKN Aerospace has
successfully concluded a
composite manufacturing
and assembly research
programme using of out of
autoclave (OOA) processes
and materials and PI shaped
woven preforms.
These technologies are
among those with the
potential to transform the
future manufacture and
assembly of large compo-

site aero-structures - and
produce the performance
gains the industry seeks
in the next generation of
airframes.
The OOA Composite
Processing Phase II programme used OOA materials to design, develop and
manufacture an affordable,
lightweight, blended aircraft
wing box featuring integrally stiffened skins, complex
contours and four different
stringer shapes (Figure
§). The manufacture of
the parts used vacuum bag
technology and the low cost
tooling that becomes practicable when curing outside the extreme autoclave
environment. The wing box
was then assembled using
fastener free, impregnated

PI joints.
Stephen Grojean, Materials
and Process Engineer, GKN
Aerospace explains: “As an
industry we are striving to
improve airframe manufacture by reducing airframe
cost and weight. To achieve
these goals we are designing
larger, lighter, more integrated aircraft structures. This
programme addresses two
of the major challenges we
face - overcoming the limitations imposed by autoclave curing and proving
effective fastener free, joining processes. The results
we have achieved serve as a
technology enabler allowing
us to progress to next stage
in composite wing structure and blended wing box
manufacture.”

Fig. 6: OOA Composite Processing Phase II wing box structure

Aerospace has introduced innovations across product design, and
manufacture including material deposition, tooling and forming,
finishing, assembly and testing. An automated fibre placement
(AFP) process uses a robotic head to lay down 16 tows of material
at a rate of around 7-10 kg of material an hour to produce the wing
spars. The spars could not be made using traditional hand lay-up
processes for two reasons: Speed and consistency of quality. Hand
lay-up is only achieved at a rate of approximately 1 kg of material
per hour - just 1/8th the AFP speed. Hand lay-up also cannot

achieve the production consistency and fine tolerances required for
the structure. The company also designed and developed a state
of the art automated facility that assembles the wing fixed trailing
edge (FTE) parts to the rear spar. GKN Aerospace then delivers the
complete FTE to the Airbus facility at Broughton, North Wales, UK.
GKN also manufactures the composite components for the aircraft
wing’s inboard and outboard flaps.
• GKN Aerospace is also the largest supplier of composite horizontal & vertical tail plane details to Airbus today.

No81 May-June 2013 /

jec composites magazine 9

http://www.gkn.com/aerospace

JEC COMPOSITES MAGAZINE - Issue #81 - May/June 2013

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #81 - May/June 2013