JEC COMPOSITES MAGAZINE - Issue #96 - April 2015 - 63

Fig. 2: Features of tape-braided preform processing

In comparison to composites using
thermoset matrix systems, composites
with thermoplastic matrix materials
are superior not only in terms of
achievable cycle times, but also in
terms of damage tolerance, impact
resistance, shelf life and recyclability.
Especially, the weldability and thermoformability of FRT profile structures offer novel and diverse options
to add value to the structural part by
further enhancing the degree of function integration in subsequent process
steps. In combination with injection
moulding technology, for example,
the high load-bearing capacity of the
FRT structure can be combined with
the advantages of injection moulding
technology to form complex-shaped
functional elements such as gears, pulleys, bearing seats and screw bosses
that are cohesively connected to the

Fig. 4: Appropriate description of the tape braiding undulation path

FRT structure in short, fully-automated production cycles.

Design of tape-braided
FRT structures
The properties of tape braid-based
functionalized CFRP structures not
only result from the material properties of the tape products used, but are
also strongly influenced by the preforming, consolidation and functionalization process step (Fig. 3).
To take the occurring influences into
account and to ensure consistent
dimensioning of high-quality FRT
structures, each of the process steps is
analyzed separately.

This includes the selection of a
suitable fibre-matrix combination for
the tape product, the tailoring of the
braid architecture according to the
requirements of the
application and the
prediction of the
resulting mechanical properties of
the defined architecture, which are
mainly affected by
the textile preforming process and
the chosen consolidation process.
In general, the
in-plane mechanical properFig. 3: Factors influencing the properties of functionalized tape-braided FRP
ties of braided

fibre-reinforced composites are
reduced as undulations are induced
by the textile architecture of the
preform. Compared to roving-based
braids, the undulation waviness of
tape braid-based composites is lower
as the tapes' thickness-to-width ratio
is smaller and the filaments are well
aligned inside the tape. This makes
the thermoplastic tape braiding technology predestined for high-performance composite components, but an
appropriate tape-based micromechanical description model is required to
predict the composite's properties.
The ILK scientists have analyzed
alternative modelling approaches
and experimentally verified a novel
description of the undulation path
which shows, compared to the common sinusoidal approach, a reduced
deviation of more than 30% to the real
alignment of the fibre (see Fig. 4).
Based on the new fibre path model, a
micromechanical software tool that

In Brief
Thermoplastic tape braiding
- Benefits
- High-performance fibrereinforced thermoplastic
profiles
- Braiding of pre-consolidated
thermoplastic tapes
- Load-adapted, near-net-shape
tape preforms
- Short cycle time consolidation

structures

No96 April 2015 / jec

composites magazine 63
JEC COMPOSITES MAGAZINE - Issue #96 - April 2015

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #96 - April 2015
