JEC COMPOSITES MAGAZINE - Issue #101 - November/December 2015 - 53

Focus

Fig. 2: Properties of an epoxy resin

low density. All these characteristics make it
possible to produce high-quality composites that can be used in a wide range of
applications.
Several prototype panels were developed
using different processes. The pressure, curing temperature and time were optimized
to produce a panel with the expected aspect
and properties. As part of a sustainable
development approach, the team focused
on energy savings and the reduction of

Fig. 3 : Bamboo sandwich panel

Fig. 4 : Mechanical properties of (1) reference
glass, (2) bamboo skin (45°) and (3) bamboo skin
(0°) sandwich panels

consumables during the development of
bamboo-based sandwich panels.

Mechanical characterization
and fire behaviour
The sandwich panels made with bamboo
skins were mechanically tested. Threepoint bending tests were conducted on
several specimens, each composed of
a honeycomb core and two skins. Two
bamboo panels with different skin directions were compared to a reference, namely
a standard glass fibre sandwich panel. The
three types of panels had the same core
(honeycomb), approximately the same
thickness (around 12.5 mm) and the same
weight (around 2.6 kg/m²).
These tests highlighted very good mechanical properties for the bamboo panels.
Indeed, the two types of bamboo panels
exhibited higher flexural strength and a
lower deflection than the standard glass
fibre sandwich panel. These results are really
promising and show all the potential of
bamboo fibres as compared to glass fibres.
For compliance with existing standards in
areas such as aeronautics, fire tests were
performed on bamboo sandwich panels.
Because of their composition, natural fibres
are very sensitive to fire and hardly fulfil
fire requirements. Preliminary work was
conducted to enhance the fire resistance
of reinforcements. For health and environmental reasons, no halogenated fire
retardants were tested. The fire tests on
treated bamboo fibres indicated that these
treatments promote char formation and are
useful to retard fire spread. Bamboo sandwich panels will be soon tested according
to the FAR 25.853 norm, the international

VESO Concept is a mechanical engineering
company created in 2008. It conducts R&T
work on biocomposites for transport applications and for sports & leisure activities in
order to develop tomorrow's new generation of materials. It also designs architectural and structural parts using these materials. The company's objective is to reach a
100%-eco-friendly structural material with
a low environmental impact. VESO's policy
relies on creativity and research to propose
new sustainable solutions.

standard for aeronautics. A study is also
underway to improve the manufacturing
process and to unlock a number of remaining technological issues.

Conclusion and prospects
A sandwich panel reinforced with bamboo
natural fibres was successfully produced and
its mechanical and fire performance was
assessed. The results are very encouraging:
the panel's mechanical properties are higher
than those of the glass fibre panels commonly used in aeronautics. Additional tests
need to be performed to assess its fire performance and self-extinguishing properties.
This showed that natural fibres and bamboo
fibres are suitable for the development of
high-added value biocomposites for hightechnology industries such as automotive or
aeronautics. VESO Concept is now working to propose a new panel where the core
(honeycomb) will also be based on natural
reinforcements and biosourced resins.
This concept seduced Airbus and VESO
Concept received an award from Aerospace
Valley and Airbus during the last Paris Air
Show in Le Bourget. n
Acknowledgements
The research leading to these results
received funding from the European
Union's Seventh Framework Programme
(FP7/2007-2013) for the Clean Sky Joint
Technology Initiative under grant agreement no. 632587.

No101 November - December 2015 / jec

More information:
www.veso-concept.com

composites magazine 53

http://www.veso-concept.com

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #101 - November/December 2015