JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 38

design

MSN 2 and 4 flight formation: route for certification

material, hand-laid GFRP fairing and a
multi-material vertical tail plane cover.
Designers are fully aware of the challenges
posed in the design of primary structures,
which is not appreciated by others further
downstream in the industrialization
process.
The transition to more complex primary
structures is detailed below in chronological order:
- 1970s: A300 first twin-engine wide
body, has less than 5% composites in
its structure, including GFRP fairings,
radome and leading edge parts and CFRP
spoilers, airbrakes and rudder. The vertical
tail plane (VTP) in the A300-600R and
A310-300 is the first primary structure
made from CFRP.
- 1980s: A320 first fly-by-wire single aisle,
has about 10% composite, most notably
the VTP and horizontal tail plane (HTP),
both CFRP primary structures. It took 10
years to double the percentage of composites in the structural weight.
- 1990s: A330/340 first long range with
wet trim tank (HTP) made from CFRP,
as well as the rear pressure bulkhead and
the keel beam. When GFRP floor panels
are introduced in the A340-600, together
with thermoplastic fixed leading edge
J-noses, the composite percentage rises to
12% of the aircraft structural weight.
- 2000s: A380, very large airliner - besides
the centre wing box, most of the empen-

nage (VTP+HTP+S.19) is CFRP; upper
fuselage is made from GLARE. All these
primary structures increase the composite percentage to just over 20%; it took
approximately 20 years after the A320
introduction to double again the percentage of composites in the structure.
- 2000s: A400M medium military tactical
transporter - 30% of the structure made
from composites, namely wing box spars
and covers (major primary structures
made from CFRP).
- 2010s: A350XWB new long-range aircraft family - less than 10 years after A380
EIS, composite % doubled again (53%);
includes largest ever monolithic CFRP
wing covers (~33 m), spars and fuselage
panels.
This illustrates that in 40 years the market
put greater demands on engineering that
forced an increase in the capability of
the composite design tools necessary to
deliver the expected accuracy in a much
higher rate assembly environment.

From ply-book to 3D model
It is not the intention of this paper to do a
comparative study between the different
techniques used to generate the design
data set. The main purpose is to portray
the evolution of the composite design
tools necessary to meet the increased
component complexity.
Ply-books were extensively used during

38 jec composites magazine / No89 May 2014

the early aircraft composite developments; each ply was separately defined in
a "book"; one ply-book per part.
As part complexity increased, ply-books
became inadequate. Fortunately this coincided with the dawn of the first computeraided design (CAD) software; at first in
2D, then 2.5D and finally 3D. None of the
early CAD systems had composite design
modules as standard, so Airbus Engineering developed their own scripts and
later on engaged a CAD system supplier
to integrate the code in the mainstream
application. This strategy had limited
success, therefore the efforts by CAD
vendors to develop composite-dedicated
code continued.
The first dedicated, commercially-available composite part design tools became
usable during the A400M aircraft development and Airbus and suppliers used them
with variable degrees of success, but they
were used in parallel with the in-house
developed code. A multitude of software
programs were used in the A400M to
design composite components but none
of these on its own could be considered
as fully suitable and efficient enough to
design ever more complex parts.
When the A350 was launched, the necessity arose to have only one single composite part design toolset, which ideally
should include the best features of the
in-house developed algorithms.
A partnership was formed with Dassault
and a joint effort improved their composite part design toolset, which now
includes most of the features developed by
Airbus during the early years. It is being
used extensively in the A350 at Airbus and
its suppliers and also elsewhere, wherever
there is a need to design more complex
and accurate composite parts.
The "GRID" approach is the newest methodology resulting from this partnership,
which was used to design, among many
others, the wing box covers. Its implementation will be briefly described.

From hand to automated lay-up
This section intends to show how part
complexity, size and production rate affect
the lay-up process and the intrinsic link to

JEC COMPOSITES MAGAZINE - Issue #89 - May 2014

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #89 - May 2014