JEC COMPOSITES MAGAZINE - Issue #78 - January/February 2013 - 30

structure

An innovative wind blade sparcap technology

By
Matthieu Landais
Business Development Manager
Epsilon Composite Americas

arboglulam® is an Epsilon Composite patented technology that
consists in assembling/stacking pultruded laminates with high compressive
properties. This technology provides
an industrial process that is quicker,
cleaner, efficient and reproducible
wherever it is used. Higher compressive
performance is guaranteed in the final
structure, as well as thinner, lighter wind
blade sparcaps resulting in cost reductions.

A technology based
on two simple ideas
The first idea was to propose a process
designed for the high volumes required by wind blade manufacturers that
would allow high-quality production
(with a low standard deviation) at low
cost anywhere in the world. This can be
achieved using a well-known process
called pultrusion, probably the most
effective and stable production technology for composites.
The second idea was to improve the
compressive properties of the composite material. To this end, the company

Epsilon Composite, a 25 years old company fully dedicated
to carbon fiber-epoxy pultrusion, has implemented a new
windbalde sparcap technology: The Carboglulam®.
An efficient industrial process regardless of the final production place and higher compressive performances guaranteed
in the final structure are the advantages brought by the
solution.

worked on three parameters. First, the
fibre content (by volume) was increased
to achieve higher mechanical performance in the composite. Second, the
fibres were perfectly aligned in the 0°
axis to help avoid micro-buckling. To do
this, Epsilon Composite designed a special pultrusion line to manage each fibre
alignment independently. Finally, considering that resin composition is also a
key factor, the resin modulus, toughness and adhesion on the fibre were
enhanced for Carboglulam® (resulting in
higher interlaminar shear strength).

Interesting properties
Therefore, micro-buckling of the fibre
itself is reduced and its compressive
properties enhanced.
The resulting laminates with high
compressive properties are delivered
as a spool to the blade manufacturing
factory. Depending on the geometry
of the sparcap, various dimensions are
available. The product is delivered with a
peel ply that gives a rough surface when
removed and ensures a clean product
surface until the product is applied. This
results in excellent bonding properties
without storage or cleaning issues.
The product is then very easily and
quickly applied by an operator. Further-

30 jec composites magazine / No78 January - February 2013

more, as the resin/fibre mix and the fibre
alignment are produced industrially, the
high standard variation introduced by
manual labour is eliminated.

Fig.1: Spools of carbon laminate with high
compressive properties

Benchmark
Carboglulam® was benchmarked against
fabric and prepreg values, for a carbon
fibre type commonly used in wind blade
applications.
Epsilon Composite’s values were
provided by IMA Dresden. The laboratory values for the prepreg and fabric
come from the carbon fibre supplier’s
technical sheets. Full-scale values were
obtained thanks to a market analysis
based on answers from various wind
blade manufacturer engineers.
The values mentioned in the technical

JEC COMPOSITES MAGAZINE - Issue #78 - January/February 2013

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