Thermosets and thermoplastics set to compete for composite ... - AVK

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While much attention is paid to the use of plastics in cars, the ecological and economic
benefits of plastic solutions are just as important in commercial vehicles. David Vink
looks at how thermosets and thermoplastics are appearing in carbon and glass fibre
composite monocoque haulage trailer designs
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�n October 2010, the Aldi Süd discount
retail chain started to use a
new refrigerated truck trailer for
deliveries to its German stores. Team
Composite (TTT) designed the
trailer with a monocoque, thermosetting
(epoxide resin) based, carbon fibre
reinforced plastic (CFRP) structure.
Before the Aldi Süd trucks hit the
road, a 13.6m long, 2.6m wide modelwas
on display at the IAA commercial
vehicle fair in Hannover, Germany, in
September.
The company says benefits of the
new structure include 25-30% lower
fuel consumption because of the low
overall 6.2 tonne weight (when the
vehicle is unloaded). The structure
includes refrigeration equipment, a lifting
axle and roller shutter door, and has
a more aerodynamic contour than conventional
steel trailers.
Aldi Süd says it saves 3 tonnes in
weight with the new trailer, which can
carry at least as much as the usual
17-tonne payload. Fuel consumption is
cut from 35 l litres to 26.5 l litres per
100km, saving �11,400 over an average
annual distance of 120,000km.
Furthermore, the company says it
will save emission trading costs in future
because CO 2 emissions are reduced by
around 15%. Other claimed benefits
include lower overall life cycle costs, larger
loading volume, palette carrier and
side protection functional integration, as
well as improved driving safety and load
security.
TTT says the chassis and superstructure
form a watertight closed unit,
keeping wind and turbulence at bay. A
truck with engine power below 300bhp
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is more than adequate to pull the trailer,
it says.
Ria Kaiser, a TTT project engineer
working on the CFRP trailer, says:
“CFRP is a first choice for refrigerated
trailers, as this material is temperature
neutral – it does not expand and does
not fatigue”.
TTT uses Zoltek’s low-cost industrial
grade carbon fibre, in the CFRP
composite to keep production costs
low. Production costs of the present
trailer are 20-30% higher than the typical
�150,000 price for a conventional
trailer, but the expense is amortised
within two years because of lower fuel
costs, Kaiser stresses.
Kaiser also highlights the insulation
provided by micro-porous silicic acid
based vacuum insulation panels (VIP),
made by Vaku-Isotherm, which are
placed under the CFRP cladding. This
ensures a long lifetime for the trailers
once they go into series production in
2015, she says.
By then, Kaiser believes that information
gained from practical load
bearing studies means the company
will be able to trim the trailer down
even further. Meanwhile, two more
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CFRP trailers will have entered service
for Aldi Süd by the end of December
2010. Another three prototypes should
follow soon afterwards.
By 2015 the company will move
from manual construction, with a
maximum capacity of two trailers per
month, to industrial production of
40,000 trailers per year, and aims to
gain a 10% share of the European trailer
market by 2020.
European trailer production has
declined recently, but reached a peak of
292,000 units in 2007, according to the
Clear consultancy group.
Investment in the CRFP trailer
project so far totals �3.2m, with contributions
from a number of different
partners, including the German state
of Lower Saxony and Nbank.
Companies involved in the project
include the Fraunhofer IFAM institute,
which specialises in production technology
and applied material research
for bonding and surface technology.
Resin and adhesives specialist Sika provided
the CRRP composite’s low viscosity
epoxide resin.
Other project partners include
Lammilux Heinrich Strunz for CFRP
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cladding sheets, Diab for sandwich
composite panels, Exel for pultruded
carbon and glass fibre reinforced components,
Airtech Europe for vacuum
bagging and composite tooling materials,
and Frimo for tools.
The CFRP monocoque structure is
produced by boat building company
Hatecke. Hatecke had previously only
made GRP lifeboats and high-speed
rescue boats at its Drochtersen-
Kautsand boatyard. The Aldi Süd trailer
is the company’s first CFRP project.
Peter Hatecke says GRP and CFRP
materials are similar enough for the
company to manage the project based
on its boatbuilding experience
Longer term, Hatecke envisages his
company developing into “a real CFRP
development centre for vehicle construction”.
With carbon fibre prices
expected to drop by around 50%, Hatecke
believes his company will benefit
from a boom in demand for CFRP trailers.
This should happen, he says, as long
as no other form of competing lightweight
trailer is developed as an alternative
to the TTT-designed CFRP trailer.
However, an alternative to the TTTdesigned
CFRP trailer is currently being
developed in Germany. At the Composites
Europe 2010 fair in September, the
IVK plastics processing institute, based
in Aachen, presented a flat-bed trailer
made of polymerised thermoplastic
PBT composite. The trailer was developed
as part of a �2.6m European 6th
Framework Cleanmould project.
At the annual AVK federation of
reinforced plastics innovation awards,
the institute won second prize in the
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environment category for a 13.6m
Cleanmould glass fibre reinforced PBT
monocoque truck semi-trailer. IKV
says the 600kg trailer part is “one of the
world’s largest parts to be made in one
shot in thermoplastic fibre reinforced
plastic”.
The Cleanmould trailer part is
made using a low 26 mPas viscosity
CBT (cyclic butylene terephthalate)
resin at 190°C. It enables high 60vol%
reinforcement and production of large
parts by liquid compound moulding
(LCM), without the use of presses.
IKV says that in contrast with thermosets,
CBT is clean to handle as it is
solid at room temperature and keeps
the workplace free of emissions.
A glass fibre reinforced CBT composite
based trailer has an overall
weight of 1,500kg, half of that of a steel
version, cutting overall weight by 15%.
The aerodynamic design reduces drag
by 21% and the overall fuel consumption
drops by 10%, as 20% less power is
needed to pull a plastic trailer.
A CBT composite trailer not only
cuts CO 2 emissions and carries
heavier loads, it is also more easily
recycled at the end of its 40-year lifetime,
double the 20-year lifespan of a
steel trailer.
To recycle the trailer, the post-use
composite is cut and ground into fibre
lengths. These are mixed with virgin
PBT resin then the mixture is plasticised
in a compounding extruder. The
extruder produces strands or chopped
strand granulate for compression or
injection moulded new parts respectively.
Although this process forms a
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completely closed recycling loop, the
new parts clearly differ from the trailer
from which they are produced.
IKV developed Cleanmould’s CBT
resin infusion, injection system and
mouldings. Aside from Cyclics Europe,
other Cleanmould partners are materials
R&D company EPL Composite
Solutions (former Euro-Projects), military
boatbuilder BAE systems Surface
Ships, boatbuilder VT Halmatic (former
Vosper Thorneycroft) in the UK,
Ahlstrom Glassfibre in Finland and
trailer producer Basmiler in Portugal.
EPL recently designed a 10m long
modular lightweight fibre reinforced
composite semi-trailer as part of a
three-year Roadlite project, in collaboration
with VT Halmatic, Nottingham
University in the UK and Leyland
Technical Centre (LTC). The Roadlite
trailer can be extended to 13.6m length,
but the 10m unit saves 400kg, or 25%
weight, compared to steel, says EPL.
According to EPL, European road
transport will grow 25% over the next
15 years and it already accounts for
10% of total European energy consumption,
contributing to over 30% of
total CO 2 emissions.
Whether the TTT/Hatecke thermosetting
CFRP, Cleanmould thermoplastic
GRP or other lightweight trailers
gain a larger market share than
conventional steel trailers remains
unclear.
Ultimately it will depend on relative
material and industrial production
costs and the associated opportunities
it presents on economic and environmental
grounds.
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