158
5 Projectile Penetrations into Coarse Aggregated UHPCC Targets
target. This should be the reason why the projectile failes to perforate the CA-UHPC
target. Therefore, the anti-perforation performance of UHPC targets is improved with
the rise of the coarse aggregates strength (hardness), and the penetration resistance
of CA-UHPC is much better than that of the other three targets.
5.4.3.3 Projectile Trajectory
Considering that the projectiles sometimes impact the target with a certain oblique
angle, and in order to analyze the influence of different aggregates on projectile
trajectory, the numerical simulations of projectiles impact aggregated UHPC targets
by different oblique angles (5, 10 and 15°) are performed in the present section. The
impact velocity of projectile is 1000 m/s. Figures 5.49 and 5.50 show the effective
stress contours of projectiles penetration into different aggregated UHPC targets
and the corresponding damage states of projectiles, respectively. It indicates that
although the size and distribution of four kinds of coarse aggregates within the UHPC
targets are the same, but the ballistic trajectories of projectiles penetrating different
aggregated UHPC targets are obviously different. Furthermore, it can be seen from
the comparison that the deflection and deformation of projectiles penetrating the CAUHPC and QA-UHPC targets are more serious than that of projectiles penetrating the
other two UHPC targets. Therefore, the UHPC targets with high strength (hardness)
aggregates can increase the deflection and deformation of projectile to improve the
impact resistance of the targets.
5.5 Summary
In this chapter, the impact resistance of coarse aggregated UHPCC target against the
medium caliber projectile is studied experimentally and numerically, the main work
and conclusions are as follows:
(1) In Sect. 5.2, the high-speed projectile penetration tests on UHPCC targets
with the striking velocities at 510–1320 m/s were carried out. It derives
that, the projectile impact crater dimensions enlarges with the increase of the
compressive strength of the target and the projectile striking kinetic energy, and
decreases with the increase of fiber mixing fraction. Within the variation ranges
of the discussed parameters, the influential degree of mixing fibers seems to
be much greater than that of compressive strength. The influential degrees of
the impact kinetic energy in enlarging the crater dimensions as well as the
fibers in reducing the crater dimensions are dependent on the amounts of the
fibers as well as the projectile striking velocity; The compressive strength, the
fiber mixing fraction as well as coarse aggregates can help to decrease the
DOP of the projectile and thus enhance the impact resistance of the target,
5 Projectile Penetrations into Coarse Aggregated UHPCC Targets
target. This should be the reason why the projectile failes to perforate the CA-UHPC
target. Therefore, the anti-perforation performance of UHPC targets is improved with
the rise of the coarse aggregates strength (hardness), and the penetration resistance
of CA-UHPC is much better than that of the other three targets.
5.4.3.3 Projectile Trajectory
Considering that the projectiles sometimes impact the target with a certain oblique
angle, and in order to analyze the influence of different aggregates on projectile
trajectory, the numerical simulations of projectiles impact aggregated UHPC targets
by different oblique angles (5, 10 and 15°) are performed in the present section. The
impact velocity of projectile is 1000 m/s. Figures 5.49 and 5.50 show the effective
stress contours of projectiles penetration into different aggregated UHPC targets
and the corresponding damage states of projectiles, respectively. It indicates that
although the size and distribution of four kinds of coarse aggregates within the UHPC
targets are the same, but the ballistic trajectories of projectiles penetrating different
aggregated UHPC targets are obviously different. Furthermore, it can be seen from
the comparison that the deflection and deformation of projectiles penetrating the CAUHPC and QA-UHPC targets are more serious than that of projectiles penetrating the
other two UHPC targets. Therefore, the UHPC targets with high strength (hardness)
aggregates can increase the deflection and deformation of projectile to improve the
impact resistance of the targets.
5.5 Summary
In this chapter, the impact resistance of coarse aggregated UHPCC target against the
medium caliber projectile is studied experimentally and numerically, the main work
and conclusions are as follows:
(1) In Sect. 5.2, the high-speed projectile penetration tests on UHPCC targets
with the striking velocities at 510–1320 m/s were carried out. It derives
that, the projectile impact crater dimensions enlarges with the increase of the
compressive strength of the target and the projectile striking kinetic energy, and
decreases with the increase of fiber mixing fraction. Within the variation ranges
of the discussed parameters, the influential degree of mixing fibers seems to
be much greater than that of compressive strength. The influential degrees of
the impact kinetic energy in enlarging the crater dimensions as well as the
fibers in reducing the crater dimensions are dependent on the amounts of the
fibers as well as the projectile striking velocity; The compressive strength, the
fiber mixing fraction as well as coarse aggregates can help to decrease the
DOP of the projectile and thus enhance the impact resistance of the target,