Impact, compression after impact and bending properties of hybrid FRP aluminium foam sandwich panel / Mohd Fadzli Ismail

Sandwich structures, which are made of metal face sheet and foam core, are widely
been used in various industries due to their excellent energy absorption and impact
resistance properties. Recently, fibre reinforced polymer (FRP) composites have been
used in the fabrication of face sheets of sandwich panel due to their high specific
strength and stiffness properties. The usage of hybrid FRP composite laminate is still
new and few researches were found in this area. On top of that, the research data on
aluminium foam as a core material in sandwich panel is also limited and need to be
further studied. This research is aimed to determine the damage resistance and
damage tolerance of hybrid FRP-aluminium foam sandwich panel. Damage resistance
refers to the resistance of a material to damage when it is subjected to impact loading
and damage tolerance is the ability of a material or structure to perform safely after
damage. In this study, damage resistance is measured using impact test and damage
tolerance is determined using compression after impact (CAI) test. In addition the
bending test was also conducted in order to determine mechanical properties of the
material, such as Young's modulus and strength. The sandwich panels were prepared
using FRP composites face sheets, which consist of carbon and glass fibres
reinforcements and epoxy matrix, and closed-cell aluminium foam core material.
Drop weight impact, CAI and three-point bending tests were conducted in order to
evaluate the properties of hybrid FRP-aluminium foam sandwich panel when
compared to those of the pristine materials and aluminium honeycomb sandwich
panel. The results showed that the hybrid FRP-aluminium foam sandwich panel has
higher damage resistance or impact properties which were represented by higher peak
force, energy absorption and specific energy absorption of 42%, 42%, and 20%,
respectively, when compared to the neat CFRP-aluminium foam sandwich panel. In
addition, it also has higher peak force, energy absorption and specific energy
absorption of 135%, 1503% and 560%, respectively, when compared to the hybrid
FRP-aluminium honeycomb sandwich panel. The damage tolerance or CAI properties
of the hybrid FRP-aluminium foam sandwich panel were higher than those of the neat
CFRP-aluminium foam and aluminium honeycomb core sandwich panels. Hybrid
FRP-aluminium foam sandwich panel exhibited lower strength reduction of 54%,
while the other sandwich panel systems recorded more than 70% strength reduction.
Furthermore, the hybrid FRP-aluminium foam sandwich panel showed higher flexural
strength and modulus by 309% and 333%), respectively, compared to the neat
aluminium foam panel. It is also exhibited higher flexural strength and flexural
modulus, by 338% and 136% respectively, when compared to the hybrid FRP aluminium
honeycomb sandwich panel. As a conclusion hybrid FRP-aluminium foam
sandwich panel has better impact resistance and CAI properties when compared to
conventional honeycomb sandwich panel. Therefore, this material is a promising
advanced material that can be used to improve damage resistance and damage
tolerance properties of modern structures.