JEC COMPOSITES MAGAZINE - Issue #111 - March 2017 - Special JEC World - o - 110

TECHNOLOGY

110
114
116
119

Simulation

A virtual test lab for structural composite materials
Natural fibres

Flax fibre composite for vibration damping design
Behaviour

Life cycle prediction of composite structures
Pultrusion

Lighter, stronger and cheaper carbon profiles

TECHNOLOGY simulation

A virtual test lab
for structural composite materials

CARLOS GONZÁLEZ,
Senior Researcher, Structural
Composites
CLÁUDIO S. LOPES,
Senior Researcher, Design and Simulation of Composite Structures
IMDEA Materials Institute

Fibre-reinforced polymers (FRP) have been progressively applied as structural materials during the past 50 years and are now extensively used in
applications where, in spite of their high cost, their unique combination of
low density, high stiffness and strength as well as toughness is a competitive advantage. Remarkable examples can be found in sectors such as
aerospace, with modern commercial and military aircraft employing over
50% of composite materials by weight; automotive, with electric cars
pressing on low vehicle weight associated with extended battery ranges;
and also in the energy and sports sectors.

T

he performance of FRP can be traced to their efficient
hierarchical structure with three levels of organization:
ply, laminate and structural element with different
dominant length scales. Owing to this hierarchical structure,
FRP are built following a bottom-up approach that begins
with the individual plies stacked to form multidirectional laminates that, in turn, are assembled into structural elements. The properties at each level can be carefully controlled from the matrix and fibre volume fraction and spatial
distribution at the ply level, the stacking sequence and the fibre architecture in each ply at the laminate level and, finally,
the spatial disposition of the laminates to form the structural element. This high performance encompasses toughness,
which is also a result of the hierarchical structure of FRP that
leads to the dissipation of energy at different length scales
during deformation and produces tough materials from brittle constituents, mimicking the structure and behaviour of
the toughest materials in nature. As a result, composites with

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jec composites magazine / No111 March 2017

optimum mechanical properties can be designed for each
application. For example, in the aerospace industry, FRP
need to satisfy stringent certification requirements regarding
stiffness, resistance to damage and failure, as well as damage
tolerance. On the other hand, when suitably designed and
triggered to fail, these materials may exhibit high specific
energy absorption and are of interest for lightweight energy
absorbing structural elements in the automotive industry.

Fig. 1: Composite materials are used in a wide range of applications
Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #111 - March 2017 - Special JEC World - o
