JEC COMPOSITES MAGAZINE - Issue #84 - October 2013 - 44

delamination

Experimental investigation and modelling
of TeXtreme® spread tow composites
To stay competitive and meet greenhouse gas
emission targets, the aircraft industry needs to
manufacture lighter and more efficient. This is
why carbon fibre reinforced polymers are being
introduced extensively into aircraft and aeroengine structures. However, the weight savings
are being limited by factors such as the "black
aluminium" approach, quasi-isotropic layup
rules with minimum percentage in each fibre
angle, minimum skin thicknesses and limitations in the material grades used. Considerable
weight savings may be achieved by challenging
the current design rules and introducing new
material developments using thinner ply thicknesses.

TeXtreme®
spread tow
fabrics are
produced by interlacing spread
tow tapes to
produce fabrics
(Figure 1)
with practically no crimp,
i.e. very little
out-of-plane
waviness due
to the weave
geometry (see
Figure 2).

Fig. 1: TeXtreme® Spread Tow tapes and fabric

Fig. 2: Micrograph with 50x magnification showing mesoscale features in a 100gsm TeXtreme® laminate (average tow inclination angle measured: α ≈3°)

By
Fredrik Ohlsson,
Product Development Director,
Oxeon

pread tow technology makes it possible to produce thin
unidirectional (UD) tapes from large tows (12k filaments and above) by increasing tow width, and thereby
reducing the weight per unit area significantly. By spreading
tows into very thin tapes, one can manufacture both woven
fabrics and UD tapes with superior mechanical properties
and also potential weight savings compared to conventional
carbon fibre reinforcements such as non-crimp fabrics (NCF)
and traditional woven fabrics. Oxeon uses the spread tow technology to produce its TeXtreme® reinforcements.

44 jec composites magazine / No84 October 2013

Typical surface weights of TeXtreme® carbon fabric are 64, 80
and 100 gsm, resulting in a significantly lower composite ply
thickness than with conventional UD prepreg materials. For
instance, using a 100 gsm fabric and vacuum infusion typically
results in a weave ply thickness under 0.1 mm, i.e. a tow thickness below 0.05 mm.
Incorporating thin plies or thin-ply-based woven fabrics into
aircraft manufacturing requires reliable design and simulation models for damage development, strength and impact
behaviour, in order to design structures efficiently using these
materials. Oxeon, Swerea SICOMP and Luleå University of
Technology are collaborating in a VINNOVA-financed project
that aims at developing design methodologies linking the chain
from manufacturing, residual stress analysis to mechanical performance under static loading. Once these material models are
developed and verified, this may be seen as the first step towards
the overall objective of further introducing thin TeXtreme® reinforcements in aerospace applications. The project also focuses
on the experimental investigation of impact response to better
understand the damage mechanisms caused by impacts on thin
tape woven composites.

JEC COMPOSITES MAGAZINE - Issue #84 - October 2013

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #84 - October 2013