Aeronautics Research 2002 - 2006 projects

Background
Strengthening Competitiveness
PreCarBi
Materials, Process and CAE Tools
Development for Pre-impregnated
Carbon Binder Yarn Preform
Composites
Composites are the material of choice
for many advanced aircraft structural
applications (A380 – 28% and Boeing 787
– 50% content) and have proven weight/
performance superiority over metals.
The critical issues today are performance
improvements: the development of faster,
more cost effective manufacturing and
simulation tools to optimise their manufacture
and design.
Today’s manufacture of advanced composites
uses either layers of pre-impregnated
plies (prepregs), or resin infusion of
dry textiles (liquid composite moulding or
LCM) to form a laminate. Prepreg composites
give superior mechanical properties
due to toughened resins, but suffer
from high material costs, limited shapeability,
expensive manufacturing and limited
shelf life. LCM can overcome many
limitations, but must use low viscosity
resins for infusion, which have a poorer
mechanical performance.
The PreCarBi project will develop new
materials (carbon fi bres and liquid resins)
as well as supporting technologies that
bring together prepreg and LCM technologies
to combine the advantages of each.
Essentially pre-impregnated carbon fi bres
with a polymer binder will be developed
for LCM and tow placement processes.
Activation via heat allows binder yarns to
be repeatedly shaped prior to resin infusion.
The binder yarns enhance mechanical
properties, have indefi nite shelf life,
and improve pre-form handling/trimming
and drapeability.
Objectives
The project includes three material specialist
partners covering fi bre, resins and
textiles, four selected research and university
partners, a fi nite element software
company and four industrial partners
representing Europe’s aircraft manufacturing
industry.
The key project objectives are:
1. the development of new binder yarns
and compatible epoxy resins
2. new energy and process effi cient
activation methods, suitable for rapid
manufacture, will be evaluated and
partially industrialised
3. modifi cations of existing AdTP (automated
tow placement) and textile
machinery to suit binder yarn processing
4. a full materials testing program to
characterise the process and mechanical
performance of binder yarn composites.
Detailed comparison with
competitive LCM and prepreg composites
will be made and the data will
provide input to the CAE (computeraided
engineering) tools development/
validation and demonstrator parts
manufacture, design and validation
5. development/improvement of existing
CAE tools for impregnation, drape,
stress optimisation and cost will be
undertaken and used to design the
three chosen project demonstrator
parts. The fi nite element (FE) codes
to be used are based on existing commercial
composite software owned by
one of the partners
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