Ballistic Perforation of Graphite/Epoxy Composite
PIYUSH K. DUTTA, DENNIS FARRELL, SUSAN TAYLOR, AZIZ TADAYON AND DAVID HUI
INTRODUCTION
istics and the impact velocities on the penetration
The response of advanced composite laminated
response of these composites. More specific objec-
plates under projectile impact has been studied
tives include development of a methodology to
extensively in recent years, but because of the pres-
characterize and analyze post-penetration fracture
ence of a large number of fracture modes and of
surfaces both in macro- and in micro-scale. Earlier
the complex response of the constituent materials
work conducted by Altamirano (1991) and
to the extremely high strain rate, the process has
Mayer* (Fig. 1) demonstrates an empirical rela-
not been completely understood. Although the
tionship between the energy absorption function
penetration event occurs in a matter of only sev-
E and the impact velocity V as:
eral microseconds, the constitutive properties of
E = CVn
the constituent materials of the composite under
(1)
such high strain rates change drastically. The gen-
eral objective of the current investigation was to
where C is a constant depending on the laminate
evaluate the influence of the laminate character-
and projectile geometry.
3
2
1
0
2.4
2.8
3.2
3.6
4.0 (ft/s)
0.72
0.85
0.98
1.10
1.22 (m/s)
Log of Impact Velocity
Figure 1. Ballistic test results of 31-ply Gr/Ep plate 12.7-mm steel sphere impact.*
* A. Mayer, U.S. Air Force Wright Laboratory, personal communication, 1992.
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