Abstract:
In this research, two thicknesses of a woven CFRP laminate have been subjected
to impact by a steel sphere in a velocity regime ranging from 170 to 374 m/s.
Impact and penetration of targets at normal and oblique incidence were studied
using high speed video. For the normal incidence targets at the higher
velocities of impact, a conical mass of laminate was ejected ahead of the
projectile. Furthermore, despite the energy transferred to the plate increasing
with impact energy, the degree of delamination in the thicker targets decreased
indicating a change in projectile penetration mechanism. Eventually, the degree
of delamination in the thicker targets appeared to approach an asymptotic level
whereas for the thinner targets the degree of delamination appeared constant
regardless of impact energy. For oblique targets, more of the kinetic energy was
transferred from the projectile when compared to the same thickness of target
that had been subjected to a normal incidence impact. However, this was merely
due to a geometrical effect. Further, thicker panels appeared to behave more
efficiently by absorbing more kinetic energy per effective linear thickness at
the lower impact energies where petalling is a dominant factor in the
penetration. This advantage appeared to disappear as the impact energy was
increased.
