Low velocity impact damage assessment in natural fibre biocomposites
Résumé
Natural fibres such as flax are a promising replacement for synthetic fibres in polymer composites
and achieve comparable specific properties due to their low density. Recent developments in the
production of technical flax fabrics allow the use of sustainable natural fibres in the manufacture of
structural composite parts. While biocomposites have been demonstrated to satisfy design and
structural integrity requirements, it is suspected that one of the limitations of natural fibre reinforced
composites is their impact resistance. In this paper, the impact behaviour of biocomposites made of
flax-epoxy and commingled flax and polypropylene fibres is investigated. Composite plates were
manufactured using compression moulding process and impact tests at several energies were
conducted using an instrumented drop tower. Force and displacement data were obtained from
accelerometer measurements and a high speed camera setup was used to observe the bottom surface of
the plates during impact. A crack tracking algorithm was developed to identify the initiation and
propagation of cracks. The force-displacement curves and high speed camera results were compared
for the flax-PP and flax-epoxy composites. The experimental study was supplemented with the finite
element modelling of the impact response of biocomposite laminates. There was a good correlation
found between the impact measurements and the FE simulations.