Environmental Engineering Reference
In-Depth Information
Z 1
Z 1
3
d
3
SP 2 Z 1
h
D
64
27 P 2
h
D s
64
27
h
D
d
s
32
27 S h
I ¼
SPd
s ¼
S
s ¼
3 ¼
D P 2
s
h
D
h
D
q 0 D 2
Substitute P 2 ¼
1
=
4
into above equation,
32
27 S h
1
4 q 0 D 2
8
27 Sh q 0 D ¼
8
27 mD
I ¼
¼
ð
2
:
53
Þ
D
Here, m is the total mass of the explosive, m = Sh ˁ 0 .
The speci
c impulse on the target is
i ¼
8
=
27
mD = S ¼
8
=
27h q 0 D
ð
2
:
54
Þ
c impulse from detonation
products is linearly proportional to the explosive mass and detonation velocity
(Lateral scattering is not considered). As we all know, the detonation products are
isotropic scattered, and not all products affect the target. So m is not the total mass
of the explosive, but the partial explosive, which directly affects the target (m is also
named effect mass)
(2) Effective mass of the packed explosive
(1) Mass of packed/charged explosive for scattering in a given direction
The effective mass (ma) of packed explosive represents the partial explosive,
which is equivalent of the explosive in a given direction. There are two different
conditions.
The above Eq. ( 2.54 ) shows that the direct speci
The effective mass (ma) of packed explosives in simultaneous detonation
To effectively solve the detonation problems, the detonation is assumed to be
simultaneous. The detonation reactions react at the same time, all explosives
become detonation products suddenly, the detonation products occupy the original
container of explosives, and all parameters of detonation products are the same
everywhere. The detonation process is extremely short. Such as the detonation of
explosives inside a container or projectile body, the detonation velocity is much
faster than the deformation of container, so detonation is considered to be simul-
taneous. Calculation of the effective mass (ma) of packed explosives simpli
es the
detonation process, without the places of detonation and directions of transportation
in consideration.
After the simultaneous detonation of cylinder packed explosives, the expansion
waves diffuse into the inside of the detonation products, and the detonation products
scatter in all directions. The scattering of detonation products in all directions is
schematized in Fig. 2.22 .
In Fig. 2.22 , h is the height of packed explosives; r is the radius; ae, be, ef, cf,
and df are wave fronts of expansion waves to all directions. The cone cdf is the
effect packing of cylinder end. The effect packed explosive mass of the cone with
height r, base area
p r 2 , and volume 1
p r 3
=
3
is given Eq. 2.55 .
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