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Waleed Al-Lafi
Waleed
Al-Lafi
Jie Jin
Jie
Jin
Mo Song
Mo
Song
Mechanical response of polycarbonate nanocomposites to high velocity impact
Loughborough University
2016
Nanocomposites
Carbon nanotubes
Impact behavior
Stress/stain curves
Materials Engineering not elsewhere classified
2016-11-10 14:10:53
Journal contribution
https://repository.lboro.ac.uk/articles/journal_contribution/Mechanical_response_of_polycarbonate_nanocomposites_to_high_velocity_impact/9234983
In this study, the mechanical responses of polycarbonate (PC) and PC/multi-walled carbon
nanotubes (MWCNTs) to dynamic loadings at low and high velocities impacts were investigated
experimentally using an instrumented falling weight impact tester (IFWIT) and a
split Hopkinson pressure bar (SHPB), respectively. The results from the IFWIT tests
revealed that impact strength, impact failure energy and fracture toughness were dramatically
enhanced by the incorporation of a very small amount of the MWCNTs into the PC
matrix. The maximum load and the impact failure energy increased by 320% and
350%, respectively, when only 1 wt% MWCNTs was incorporated. The results from the
SHPB tests demonstrate that all the materials showed strain-rate sensitivity. The
MWCNTs nanocomposites exhibited higher yield stress and energy absorption characteristics
compared to the PC matrix material. However, the enhancement by MWCNTs was very
limited for the PC containing higher percentage of the filler at higher strain rates. This
could be resulted by a thermal-softening effect. In addition, the density of the pure PC
and PC/MWCNTs nanocomposite specimens before or after SHPB testing was examined
to gain insight into the microstructure changes. The results show that the density
decreased significantly after the SPBH tests. With increasing strain rate the density
decrease in PC nanocomposite is faster than that in the pure PC. It is believed that more
cracks formed in the PC nanocomposite during the SHPB tests, which could result in high
energy dissipation.