Game Development Reference
In-Depth Information
Table 13-4.
TNT Equivalence of Various Bomb Types
Bomb Type
TNT Equivalent Explosive Mass (
kg
)
Car bomb
225-1800
Briefcase bomb
20-25
Pipe bomb
2
In addition to damage caused by the explosion itself, one of the main reasons to encase
explosive material inside an object is to cause metal fragments to fly outward from the point of
explosion. We'll discuss the effects of fragmentation next.
Fragmentation Devices
A fragmentation device consists of an explosive material that is encased in a shell typically
made out of metal. A hand grenade is an example of a small fragmentation device. When the
charge inside a fragmentation device explodes, the pressure quickly builds up inside the casing,
causing it to burst. Fragments of the casing fly out in all directions like thousands of irregularly
shaped bullets. Fragmentation weapons generally have a greater lethal range than standard
explosive devices because the energy of the fragments dissipates more slowly than the energy
of a blast wave.
The fragments from a fragmentation device are projectiles. The damage they inflict on
impact and the distance they will travel are functions of their initial kinetic energy. The theo-
retical initial velocity of the fragments is a function of the nature of the explosive charge and
the configuration of the fragmentation device.
mm
/
2
c
e
v
=Δ
2
E
(13.8)
(
)
1
+
Km m
/
c
e
In Equation (13.8), the quantity
DE
is the heat of explosion of the explosive charge. For
TNT, the value would be 2.175
e
+ 6
J
/
kg
. The quantities
m
e
and
m
c
are the mass of the explosive
charge and the mass of the fragmenting casing, respectively. The ratio
m
c
/
m
e
is also known as
the
charge-to-metal
ratio. The quantity
K
is a geometrical constant. Values for
K
are shown in
Table 13-5. Fragmentation devices are usually approximated by one of the three shapes shown
in Table 13-5. A land mine, for example, would be modeled as a flat plate, a bomb as a cylinder,
and a hand grenade as a sphere.
Table 13-5.
Fragmentation Device Geometrical Constants
Shape
K
Flat plate
1/3
Cylinder
1/2
Sphere
3/5
