JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 58

automotive
were measured.
The DMA results are illustrated in
Figure 11. At lower temperatures
(-40°C to 25°C), the mechanical
properties of the composite were not
affected. The increase in temperature
enhanced the storage modulus of the
composite by evaporation of the contained moisture. The glass transition
temperature (close to 75°C) can be
obtained from both the loss modulus
and tanδ curves. It is associated to the
crosslinking density of the composite.
The higher storage modulus above Tg
reflects the higher performance level
of the composite at high temperature. Tan δ also shows the damping
capacity of this green composite - a
sensible change in the damping factor
is observed when the temperature
increases. This factor is close to 1.9%
and 2.6% respectively at 25°C and
80°C, which is excellent (as compared
to 0.10-0.15% for common glass/
epoxy or carbon/epoxy composites).
Flexural test on a prototype
automotive part
Considering the optimal process parameters, a Flaxpreg sandwich panel
was prepared in a one-shot process
and used to produce a real automotive trunk load floor (Figure 11).
According to the customer's specifications, this luggage board was subjected to flexural and creeping tests.
The results show that the Flaxpreg
biomaterial can withstand 100kg for 4
hours at ambient temperature, and 2
hours at high temperature, thanks to
the high thermal stability of Acrodur

solid part with equivalent mechanical behaviour (Figure 13). To check
its efficiency in terms of behaviour
and deflection, two simulations were
conducted and compared to the real
flexural test:
- Simulation test with a fully discretized honeycomb spacer: the skins
and the 3D spacer parts were generated using shell elements according
to the laminates' stacking sequence
[0/90/0], dimensions and orthotropic planes (local coordination system).
The properties attributed to the
sections of the skins and the spacer
cardboard paper were determined
experimentally.

Fig. 12: (a) Flaxpreg panel subjected to mechanical
tests, (b) prototype automotive part

and the good specific mechanical
properties of the almost continuous
flax fibres. At high temperature, the
measured deflection is close to 13.5
mm, a value in accordance with the
specifications.
Flaxpreg behaviour modelling
To simulate the flexural behaviour
of automotive parts, a finite element analysis of the Flaxpreg sandwich panel was conducted using the
ABAQUS software. The difficulty was
the high computation time due to the
complex 3D geometry of honeycomb
cardboard. Therefore, an analytical
model was developed to replace the
spacer structure by a homogenous

Fig. 13: Geometry of a Flaxpreg sandwich panel studied with finite element simulation

58 jec composites magazine / No89 May 2014

- Simulation test with a homogenized
honeycomb spacer: in this case, the
composite laminate parts were represented by shell elements too but the
honeycomb spacer was replaced by a
homogenous deformable solid whose
properties were calculated by the
developed analytical method.
The resulting deflections are summarized in Table 2 below, which shows
that the homogenous model developed gives accurate results compared
to both numerical and experimental
results. According to the specifications, the model can be used to simulate several mechanical tests such as
compression and flexural tests using
a simplified structure with little CPU
time. Figure 14 presents the iso-values
of vertical displacement recorded during the simulation of the flexural tests.



JEC COMPOSITES MAGAZINE - Issue #89 - May 2014

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #89 - May 2014

Cover
Edito
Point of view: volume production
Contents
COMPANY & BUSINESS In Brief
MEA
Agenda of Events
APPLICATIONS
Race car
E-helicopter
Pipes
Consumer goods
MARKET
Brazil
U.S.
WPC
FEATURE AERONAUTICS
Integration
CMC
Prepregs
CAE
Design
Equipment
Structure
Interview
RESEARCH & DEVELOPMENT
Infusion
Process
TECHNOLOGY & INNOVATIONS
Automotive
Tow placement
Core materials
Index
In the world
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Cover
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 2
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Edito
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Point of view: volume production
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 5
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Contents
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 7
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - COMPANY & BUSINESS In Brief
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Agenda of Events
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - MEA
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 11
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Ad1
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Ad2
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Race car
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 13
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 14
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - E-helicopter
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Pipes
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 17
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Consumer goods
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 19
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Brazil
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 21
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - U.S.
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - WPC
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 24
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 25
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 26
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Integration
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 28
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - CMC
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 30
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 31
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Prepregs
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 33
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 34
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - CAE
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 36
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Design
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 38
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 39
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Equipment
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 41
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Structure
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 43
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Interview
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 45
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 46
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Infusion
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 48
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 49
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 50
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Process
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 52
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 53
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Automotive
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 55
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 56
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 57
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 58
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 59
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Tow placement
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 61
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 62
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Core materials
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 64
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - Index
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - In the world
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 67
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 68
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