Ammunition and explosives – Shells – Focused or directed detonation
Reexamination Certificate
2002-03-01
2003-09-23
Tudor, Harold J. (Department: 3644)
Ammunition and explosives
Shells
Focused or directed detonation
C102S305000, C102S492000, C102S499000
Reexamination Certificate
active
06622632
ABSTRACT:
ORIGIN OF THE INVENTION
The invention described herein was made in the performance of official duties by an employee of the Department of the Navy and may be manufactured, used, licensed by or for the Government for any governmental purpose without payment of any royalties thereon.
FIELD OF THE INVENTION
The invention relates generally to fragmenting warheads, and more particularly to the control of the polar ejection angle of fragments dispersed by a fragmenting warhead.
BACKGROUND OF THE INVENTION
Fragmenting warheads are used in a variety of military applications to deliver a distribution of high-velocity fragments to a target area. In terms of airborne warheads,
FIG. 1
depicts the essential elements of an end initiated fragmenting warhead. Specifically, a fragmentable casing
10
having a longitudinal centerline axis
11
houses an explosive material
12
. To detonate explosive material
12
and rupture casing
10
into fragments, an initiator or detonator
14
is placed in casing
10
at one end thereof. Upon initiation, a detonation wave commences at detonator
14
and propagates through explosive material
12
along the direction of the longitudinal axis
11
of casing
10
. When the detonation wave reaches casing
101
a shock wave is transmitted to the casing which, in turn, causes casing
10
to expand. Expansion of casing
10
is further facilitated by the expanding detonation product gases. Casing
10
ruptures into fragments as such expansion continues. These fragments are ejected radially outward along “polar ejection angles” measured perpendicular to the external surface of casing
10
at the specific location of rupturing casing
10
. The polar ejection angle &agr; is governed by the detonation velocity (V
D
) of explosive material
12
and the radial velocity (V
F
) of the fragments. The polar ejection angle can be approximated by one-half of the Taylor angle whereby
&agr;=arcsin[
V
F
/(2
V
D
)].
This is depicted in
FIG. 1
where dashed line
16
represents the perpendicular direction relative to the external surface of casing
102
at the point of a particular polar ejection angle measurement. For a typical warhead, the polar ejection angle for the end initiated fragmenting warhead just described is approximately 7 degrees. As is known in the art, variations in polar ejection angle occur near each end of the warhead due to the build-up of the detonation wave and discontinuities in end confinement of the explosive material.
The essential features of another type of airborne fragmenting warhead are illustrated in
FIG. 2
where detonators
24
and
26
are located at the respective forward and aft ends of the warhead. Detonators
24
and
26
are initiated simultaneously. Upon initiation, detonation waves starting at detonators
24
and
26
propagate through explosive material
14
from either end of the warhead. In this example, the polar ejection angle for the vast majority of the fragments is approximately 0 degrees due to the meeting of the two detonation waves originating from each end.
Unfortunately, there are many instances where the fixed polar ejection angles of 0 degrees or 7 degrees (generated by the above-described fragmenting warheads) do not provide the needed flexibility for a particular mission. Further, since the polar ejection angles in these examples are fixed, the warhead's ability to adjust to a changing or moving target scenario is non-existent or at least severely limited.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide for polar ejection angle control of a fragmenting warhead.
Another object of the present invention is to provide the means for adjusting the polar ejection angle of a fragmenting warhead to account for changing target scenarios.
Still another object of the present invention is to provide polar ejection angles for a fragmenting warhead that can range from negative 7 degrees to positive 7 degrees in a controllable fashion.
Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings.
In accordance with the present invention, control of the polar ejection angle of fragments in a fragmenting warhead is provided. The warhead's casing is filled with explosive material and has at least two detonators spaced apart from one another and coupled to the explosive material. The detonators function in a non-simultaneous fashion to produce corresponding detonation waves in the explosive material. The detonation waves interact to control a polar ejection angle of fragments formed when the warhead's casing ruptures. The present invention includes provisions for selecting specified times of detonation for each of the detonators after the warhead is deployed.
REFERENCES:
patent: 3326125 (1967-06-01), Silvia et al.
patent: 3447463 (1969-06-01), Lavine
patent: 3648610 (1972-03-01), van Zyl et al.
patent: 4282814 (1981-08-01), Menz et al.
patent: 4658727 (1987-04-01), Wilhelm et al.
patent: 4848239 (1989-07-01), Wilhelm
patent: 5267513 (1993-12-01), Guirguis et al.
Bechtel, Esq. James B.
Bergen, Esq. Peter J. Van
Bussan, Esq. Matthew J.
The United States of America as represented by the Secretary of
Tudor Harold J.
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