JEC COMPOSITES MAGAZINE - Issue #113 - June 2017 - 66

TECHNOLOGY simulation

Fig. 5: a) SR-µCT observations of local damage initiation and observation in a PA66GF35 sample; b) damage evolution law for the same analyzed sample [3]

SR-µCT-based analyses
Based on the previous considerations and the characteristic damage
aspects identified based on SEM micrographs, in-situ tensile tests
were performed in a continuous detection mode under synchrotron
radiation at the ESRF facility (ID19 beamline). Ultra-fast synchrotron
tomography at the second duration was applied to shed more light
on the competitiveness between damage growth and coalescence in
SFRTs. Thus, full-field monitoring of microstructures submitted to fast
dynamic processes by 3D imaging techniques was required to better
understand the physical aspect of multi-scale mechanisms. In the case
of X-ray micro-tomography (μCT), processes of sub-minute durations
posed serious technical challenges. In this context, appropriate experimental equipment designed by Novitom was used to apply in-situ tensile loads in the ID19 beamline of ESRF (Grenoble, France). Figure 5
shows some of the results obtained with the big data processing procedure developed.

Conclusion
The suggested approach combining X-ray µCT and FE modelling made
it possible to assess the mechanical properties in weld lines. Moreover,
this approach provided a proof of the presence of out-of-plane oriented fibres in the weld line. The existence of such orientations even at
small fractions is the main cause of the high strain localization within
the weld line front. This data can be considered to validate and better
develop injection moulding simulation packages. Surface and volume
quantification of damage procedures allowed the implementation of
image processing protocols. These protocols were successfully applied
to characterize damage kinetics at the surface and within the sample.
These procedures can be easily extended to big data obtained by SRµCT. The experimental damage evolution laws will be used later in the
project to develop more accurate damage criteria.
More information:
http://tpcim.mines-douai.fr
frederic.roger@imt-lille-douai.fr

jec composites magazine / No113 June 2017

Acknowledgements
Thanks are due to IMT Lille Douai for funding Abderrahmane Ayadi's PhD grant, to the
Hauts-de-France Region Council for funding Hedi Nouri's post-doctoral grant (contract
no.14002212), to Peugeot-Citroën for kindly providing the mild-notched plates and the
functional parts, to Assoc. Prof. Eric Lafranche (IMT Lille Douai) for providing the injection
mould, and to Mr. Laurent Charlet (IMT Lille Douai) for his assistance during the injection
moulding and preparation of incomplete plates. The authors also gratefully acknowledge
the International Campus on Safety and Intermodality in Transportation (CISIT), the
Hauts-de-France Region, the European Community and the National Centre for Scientific
Research (CNRS) for funding the ISIS4D X-Ray CT platform, as well as the UME (ENSTA
ParisTech) for funding the synchrotron X-ray tomography experiments. Novitom's scientific staff is also acknowledged for their assistance and collaboration in preparing and
conducting the IN/708 experiment at the ID19 beamline of ESRF.
References
[1] Mock P. EU CO2 standards for passenger cars
and light commercial vehicles. Policy Update 2014.
[2] Skea M. Composites: No longer the odd-component
out. Compos. Manuf. Mag. 2014; March:14-7.
[3] Ayadi A. Modelling and experimental analyses based on microstructural
characterisation by X-ray imaging: Application to thermoplastic composites reinforced
with short glass fibres. Mines Douai and Lille 1 University, 2016.
[4] Robert G. et al. Towards integrative simulation of fatigue loadings for short glass
fibers reinforced polyamide. SAE Technical Paper. 2016-01-0379, 2016.
[5] Kleindel S. et al. Prediction and validation of short fiber orientation in a complex
injection molded part with chunky geometry. Int. Polym. Process. 2015; 30:366-80.
[6] Cruz CA. Integrative simulation for assessing the mechanical performance
of a weld line on injection moulded thermoplastic parts. Proceedings of
WCCM XI/ ECCM V/ ECFD VI, Barcelona, Spain, 20-25 July, 2014; p. 1-12.
[7] Ayadi A. et al. An original approach to assess elastic properties of a
short glass fibre reinforced thermoplastic combining X-ray tomography
and finite element computation. Compos. Struct. 2015; 125:277-86.
[8] Lafranche E. et al. Injection moulding of long glass fibre reinforced polyamide 6-6:
guidelines to improve flexural properties. eXPRESS Polym. Lett. 2007; 1:456-66.
[9] Lafranche E. et al. Injection moulding of long glass fiber
reinforced polyamide 66: Processing conditions/microstructure
/flexural properties relationship. Adv. Polym. Technol. 2005; 24:114-31.
[10] Ayadi A. et al. Determination of orthotropic properties of glass
fibre reinforced thermoplastics using X-ray tomography and multiscale
finite element computation. Compos. Struct. 2016; 136:635-49.
[11] Ayadi A. et al. Effective mechanical properties of a weldline in a short glass fibre reinforced polyamide 66 based on X-ray micro-tomography and finite element computation.
Proceedings of ICCM20, Copenhagen, Denmark, 19-24 July 2015.
[12] Ayadi A. et al. Large-scale X-ray microtomography analysis of fiber orientation in
weld line of short glass fiber reinforced thermoplastic and related elasticity behavior.
Macromol. Mater. Eng. 2016; 1-15.

http://tpcim.mines-douai.fr

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #113 - June 2017