JEC COMPOSITES MAGAZINE - Issue #111 - March 2017 - Special JEC World - 112

TECHNOLOGY xxxxx

Fig. 3: Failure envelope of a carbon-epoxy unidirectional ply predicted by the computational micromechanics module (VIPER) of the virtual test lab. The numerical results
are correlated with the Puck failure criteria

sible micro-defects produced during manufacturing, such as
porosity. This approach also adds the capability to simulate
the ply behaviour under loading conditions that are difficult
to reproduce in the physical laboratory such as biaxial or triaxial loading conditions, hence allowing the determination
of the complete failure envelope of the composite ply (Figure 3).

Fig. 4: Results of the computational mesomechanics module of the virtual test lab.
a) Virtual open-hole compression (OHC) test coupons according to ASTM D6484 /
D6484M standard; b) Virtual drop-weight impact tests according to ASTM D7136 /
D7136M (two different impact energies)

Virtual test lab
This framework constitutes a powerful virtual test lab that offers enormous support to material certification at each scale,
allowing for a great reduction in the number of mechanical
characterization experiments in the material screening phases and narrowing down final certification tests. In addition,
the influence of the changes in the constituent properties on
the structural behaviour can be readily predicted, reducing
the inertia to introduce new materials and paving the way
for optimization of the material behaviour at different length
scales.
The micromechanics module (VIPER - Virtual Ply Property
Predictor) of this virtual test lab is used to predict composite
ply properties as a function of material constituents, including the effects of environmental conditions as well as of pos-

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jec composites magazine / N°111 March 2017

The mesomechanics module of the virtual test lab, in which
the physical deformation and failure mechanisms of the plies
and ply interfaces are taken into account, provides accurate
predictions of the failure strength, toughness and damage
tolerance of virtual composite coupons, e.g. as in ASTM test
standards (Figure 4). In most cases, model predictions do not
differ from typical certification test results (plain strength;
open-hole tension and compression; drop weight impact and
compression after impact tests, etc.) by more than 10% for
typical configurations used in structural applications of FRP.
As a result, multiscale physically-based virtual testing tools
open new opportunities to optimize and push materials towards their maximum performance through a better understanding of the competition between failure mechanisms.

More information:
www.imdea.org
References:
[1] M.G. Ostergaard, A.R. Ibbotson, O. Le Roux, A.M.
Prior, Virtual testing of aircraft structures, CEAS
Aeronautical Journal 1, 83-103 (2011).
[2] C.S. Lopes, C. González, O. Falcó, F. Naya, J. Llorca,
B. Tijs, Multiscale virtual testing: the roadmap to efficient design of composites for damage resistance and
tolerance, CEAS Aeronautical Journal (2016), pp. 1-13.

http://www.imdea.org

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #111 - March 2017 - Special JEC World