http://www.scribd.com/doc/6032093/Armor-Basics
Just rikosheti pärast on vene viimase põlve tankid sellised lakutud kujuga.1.2 Geometry
1.2.1 Slope and ricochet
The next factor in determining the effectiveness of a tank’s armor is slope. On
the face of it, slope should not impact on armor design at all since the
more you incline a plate to armor a volume or profile, the more material
you need to cover that profile. Where slope becomes a factor is in the effect
it has on the attacking projectile. This means that whatever effects it has, it’s
tied to the projectile nose design as much as the armor slope.
Firstly, all projectiles will ricochet. The real question is at what angle
and velocity do they ricochet. Ricochet occurs when a attacking projectile
glances off the sloped armor of an AFV without digging in far enough to
penetrate the plate. If it has no time to dig in before it ricochets, it can’t penetrate
even modest amounts of armor. A complex model has been developed to
predict the angle at which a projectile is expected to ricochet, this is called the
‘critical ricochet angle’.1
The longer the rod, the higher the ricochet angle and the faster the rod, the
higher the critical ricochet angle. In addition, heavy metal rods of WHA or
dU2 ricochet at higher angles that steel. The critical ricochet angle is measured
from the vertical plane [i.e. 90° is horizontal]. A rod of 10:1 L/d [Length
to rod Diameter ratio] @ 1.7km/s should ricochet at ~78° when made of steel,
while its WHA /dU counterpart will ricochet @ 81°. Stretching the penetrator
to 15:1 L/d increases the ricochet angle to 82—83°, and it’s likely that 30:1
rods will ricochet at >84—85°. Tate’s ricochet formula predicts a ±5° variation
around these values, so 50% of the 10:1 steel rods should ricochet @
~78°, while ricochet will occur as high as 83°and as low as 73°. The above
cases apply to thin plate targets, but if the plate is over 4:1 T/d [plate Thickness
/ rod diameter ratio] the ricochet angles should go down a few degrees.
Since the time it takes a projectile to ‘turn’ is around 40—60 micro seconds,
and since the entire penetration event takes 300—400 microseconds [large
warhead], even shaped charge warheads [HEAT] will ricochet when the right
combination of striking velocity and angle are reached. Modern HEAT
rounds will ricochet as well, the only question is whether this is before or
after jet penetration. Modern shaped charges with standoff probes and base
initiation will start the jet penetration process before the main round impacts
the slope armor. Since this is a 400 micro second event [½ a millisecond], it is
quite likely that the main body of the round will not even have reached the
plate by then.
The second aspect of slope is the asymmetrical force acting on the penetrator.
When a projectile strikes a sloped plate, the side of the penetrator closest to
the plate will suffer more force, erosion, and damage than the opposing side.
This puts an unbalanced force on the rod, turning it in towards the plate – and
then into the opposite direction. The penetrator takes a longer overall route
through the armor, resulting in less penetration of sloped armor.
Ja miks Leopard 2A5-st paigaldatav torni lisasoomus on "nurgaga".
Aga võibolla on kõik vastupidi, tänapäevased soomusekihid on probleemivabad ja kestavad kauem kui arvatud.
Üldiselt iga töö jaoks oma riist on rohkem proffide tunnus ja universaali mehed on asjaarmastajad, või ei jaga lihtsalt asja 