US3156188A

US3156188A - Fragmentation weapon

Info

Publication number: US3156188A
Application number: US177699A
Authority: US
Inventors: Zernow Louis; Kenneth N Kreyenhagen
Original assignee: Aerojet General Corp
Current assignee: Aerojet Rocketdyne Inc
Priority date: 1962-03-01
Filing date: 1962-03-01
Publication date: 1964-11-10
Anticipated expiration: 1981-11-10

Description

Nov. 10, 1964 ZERNOW ETAL 3,156,188

FRAGMENTATION WEAPON Filed March 1, 1962 INVENTOR. LOUIS ZERNOW KENNETH N. REYENHAGEN ATTORNEY Fla-10 W United States Patent 0 3,155,188 FIhQGMENTATiGlQ WEAFGN Louis Zernow, Glendora, and Kenneth N. Kreyenhagen,

West Io-visa, Qalifl, assignors to Aeroiet-General- (Jorporation, Aznsa, @alih, a corporation of Ghio Mar. l, 1962, Ser. No. 177,699 in Qlahns. (El. NZ-57) This invention relates to a fragmentation device, and more particularly to a fragmentation device provided with means for controlling the size and shape of the fragments produced.

Fragmentation devices are primarily useful for military purposes, although there may also be a use for them in certain industrial applications. With respect to military requirements, uncontrolled fragmentation in a fragmentation-type weapon is undesirable because the explosion of the weapon results in the production of fragments which have a variation in size and weight. This variation in fragment size reduces the efficiency of the weapon against targets for which it was designed because a large proportion of the fragments will either be too large, thus wastefully overlcilling the target, or will be ineifectually small. It is apparent, therefore, that if the size of the fragments is controlled, the lethality of the weapon would be increased. Consequently, the size and weight of the weapon could be reduced without decreasing its effectiveness.

Heretofore, fragment size in fragmentation type Weapons has generally been controlled by precutting grooves in the weapon or casing during production to establish preferential fracture lines in the casing. These cutting or grooving operations, however, are expensive and time consuming, and they furthermore weaken the casing so that the usefulness of such weapons for launching from a gun, for example, is limited. What is needed, therefore, and comprises an important object of this invention is to provide a simple and economical method and apparatus for precisely controlling the size of fragments in a fragmentation type weapon which does not involve weak? ening, precutting, or grooving the casing.

The invention in its broadest aspect comprises filling a metal casing with high explosive material. An inert barrier provided with perforations or openings surrounds, encases or is contiguous with the high explosive material in spaced relation to the casing. When the igh explosive material is detonated, the resulting detonation wave is interrupted by the barrier, but continuous unhindered through the perforations or openings, forming a network of intersecting shock waves beyond the barrier. Reinforcement of these shock waves occurs along planes of interaction, causing preferential fractures by cutting or grooving in the casings where these planes reach the casing. If the perforations or openings in the barrier are equally spaced from each other, the size of the casing fragments will also be generally equal. By varying the spacing of the perforations in the barrier, the size of the casing fragments will vary. In this way, the size of one group of fragments can be controlled for optimum effectiveness against personnel and the size of another group can be controlled for optimum eiectiveness against equipment.

This and other objects of this invention will become more apparent when read in the light of the accompanying drawings and specification wherein:

FIGURE 1a is a sectional view illustrating the application of the invention to a spherical fragmentation weapon;

FIGURE lb is a plan View of a spherical weapon shown in FlGURE la;

FIGURE 2 discloses a portion of a cylindrical pen forated barrier having round perforations;

FIGURE 3 discloses a modified perforated barrier with square perforations;

FIGURE 4 discloses a semi-spherical perforated barrier with round perforations;

FIGURE 5 discloses a barrier formed from a wire screen;

FIGURE 6:: discloses a longitudinal sectional view showing this invention employed in a cylindrical fragmentation weapon;

FIGURE 6!; is a plan view of the weapon shown in FIGURE 6a;

FIGURE 7 discloses the shape of one typical fragment which can be obtained by controlling the pattern of perforations in the barrier;

FIGURE 8 is a longitudinal sectional view of a cylindrical weapon with a modified perforate barrier;

FIGURE 9 discloses a development of a. portion of a modified perforate barrier shown in FIGURE 8 but showing in greater detail the two groups of perforations where the perforations in one group are spaced further apart than the perforations in the other group; and

FIGURE 10 is a side sectional view of an enlarged portion of the cylindrical weapon shown in FIGURE 8, and showing in particular, the interaction of the shock waves passing through the perforate barrier.

Referring now to FIGURE 1 of the drawing, one embodiment of the invention comprises a spherical fragmentation-type weapon indicated-generally by the reference numeral iii. It is understood, however, that the shape of weapon is not critical. The weapon shown comprises an outer spherical casin 12; preferably formed from metal. The interior of the casing is filled with a high explosive mater al indicated generally by the reference numeral 14. A concentric, spherical, inert, perforated barrier 16 is embedded in the high explosive material.

The perforations 19 in the barrier in the embodiment shown in FTGURE 1 are filled with explosives and are substantially equally spaced from each other for reasons to become apparent below. In addition, the barrier is in spaced relation to the inner surface of casing 12. The high explosive charge is detonated by means of a conventional suitable igniter it; which initiates the explosion, preferably by acting on a detonating element 13' at the center of the spherical casing.

When the igniter is actuated and detonates the high explosive material, the detonation wave propagates radially outward as an advancing spherical front. When this wave front reaches the inert barrier its further propagation is interrupted except at the perforations.

Those parts of the wave which pass through the perforations act as point sources to form a network of tiny spherical detonation wavelets 20, shown in dotted lines in FIGURE 1. these detonation wavelets are centered around each of the perforations. 3

As these detonation wavelets propagate outwardly, they interact with each other and reinforce each other along planes of interaction indicated by dotted lines 2d, shown in FIGURE 1. Since the perforations in the perforated wave barrier to are generally equally spaced from each other, their planes of interaction will also be uniformly spaced from each other. Consequently, the casing will break into fragments which are substantially equal in size. Therefore the size of the fragments depends primarily on the spacing of the perforations in the wave barrier.

, It has been found that in the above-described structure the size of the fragments and their uniformity is af- In the region beyond the barrier,

' tween the barrier 16 and the outer casing 12.

I al

wave reinforcement along the planes of interaction will be maximized causing the casing to break into well defined fragments.

In addition, it has been found that the effectiveness of the device is also sensitive to the shape of the detonation wave reaching the perforated barrier to, and it is desirable, though not mandatory, for all parts of the detonation wave toreach the barrier at about the same instant. For this reason, point initiationof the high explosive material at the center of the spherical casing is desirable. detonation of the high explosive material will produce casing fragments of uniform size and each of the fragments will have imparted to it substantially the same amount of energy. This will result in a more efficient, better performing weapon.

The principles of this invention have been aiso applied to a cylindrical fragmentation-type weapon shown in FIGURES 6a and 6b and indicated generally by the reference numeral 26. This Weapon is provided with an outer cylindrical casing 28 and is filled with a suitable high explosive material 30. An inert perforated barrier 32 is contiguous with the high explosive material in spaced relation to the outer casing 28. As seen, the perforated barrier is cylindrical and is parallel to the outer casing 28. In this embodiment the igniter element 34 includes an actuating element 36 outside the casing and conventional means including detonating elements 38 along the axis 29 of the casing for detonating the explosive material from at least one point in the axis of the cylindrical casing. The spacing between the perforated barrier and the outer casing, the thickness of the perforated wave barrier, and the spacing between the perforations in the wave barrier, are as described above in connection with the embodiment shown in FIGURE 1.

It is apparent that the shape and size of the fragments produced when the high explosive material is detonated depends primarily on the spacing of the perforations. As shown in FIGURES 2, 3, and 4, good results can be obtained using a perforated barrier with round or square perforations extending therethrough. Barriers having perforations with other shapes may also be satisfactory. If the rows of perforations are staggered from each other, as shown in FIGURES 2, 3, and 4, the

outer casing

12 or 28 will shatter into generally hexagonally shaped fragments 40 as shown in FIGURE 7. If the rows are paral-- l'el columns, square-shaped fragments will result. Intermediate shapes can also be obtained using other perforate patterns.

As shownin FIGURE 5, it is, also possible for the barrier to be formed from a wire screen 42. One advantage of the use of the wire screen instead of a perforated barrier formed from metal or plastic is that the screen may be more economical to fabricate than the barrier in comparison to the perforated barrier disclosed in FIGURES 2, 3, and 4. i

In some circumstances, it is desirable for a fragmentation weapon to be effective against personnel and equipment. 1 Since, in general, larger casing fragments are required for effective use against equipment than against personnel, it would be desirable to design the casing. so it shatters into two or more controlled groups of fragments, where the size of one group of fragments is optimized for use against personnel, and the size of the other group of fragments would be optimized for use against equipment.

As described above, the spacing of the perforations in the wave barrier primarily determines the size of the fragments. Consequently, if it is desired to cause the With the arrangement described above, the.

casing to shatter into two or more groups of fragments having a different size, the perforated barrier must have a corresponding number of portions wherein the spacing between the perforations in one portion is different from the spacing of the perforations .in another portion.

The modified cylindrical fragmentation device 40 shown in FIGURE 8 illustrates this possibility. As shown,

it includes an outer cylindrical case 42 and an innerperforated barrier 44 surrounding the explosive. As seen.

in FIGURES 8 and 9, the perforated barrier in this par ticular embodiment has two groups of perforations 46 and 4-8 and the spacings of the perforations in each group are different. It is further noted, as seen in FIGURES 8 and 10, that the portions of the wave barrier containing perforations 46 are closer to the casing 4-2 than the portions containing perforations 48. This is in accordance with the optimum conditions recited above wherein the thickness of the wave barrier 44 is designed so that it is equal to the spacing of the wave barrier 44 from the cats ing 42, and so that the spacing between the perforations.

is designed to be twice the thickness of the wave barrier or the spacing between the Wave barrier and the casing.

In particular, if the portion of the perforated barrier 44 containing perforations 46'has a thickness I2 then the spacing between this portion of the perforated barrier and the casing 42 is preferably set equal to h and the spacing between perforations 46 is preferably'set equal to 211 (see FIGURE 10). Similarly, if the perforations 48 are spaced from each other at a distance 2/1 then the portion of the barrier containing perforations 48 should preferably have a thickness k and be separated from the barrier by a distance I1 (see FIGURE 10).

With this arrangement, as seen in FIGURE 10, when the high explosive material 50 in the casing 42 is detonated by actuating element and igniter 4% acting on detonating element 51, the detonation wave propagates outwardly. When this detonation wave reaches the perforated barrier, the portions of the wave which pass through the perforated barrier'act as point sources to produce a network of tiny spherical detonation wavelets 52 and 54 centered around perforations 4-6 and 43 respectively.

As these detonation wavelets propagate outwardly, they intersect each other and reinforce each other along planes of

interaction

56 and 58 respectively. Consequently, the casing will shatter into two groups of fragments, wherein the fragments in one group are larger than the fragments in the other.

It is further apparent that the principles applied above can be extended to cause the casing to shatter into addi tional groups of fragments wherein the fragments in each group are substantially the same size. rated barrier 44 will shatter when the device is detonated, the wave barrier itself could be formed from metal or some other suitable material to increase the number of fragments produced and thus increase the effectiveness of the weapon.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in V and the resulting detonation wave coacting with said barrier so that when the detonation Wave reaches said barrier, parts of the detonation wave pass through the openings and form a network of detonation wave interactions Since the perfobeyond the barrier in the space between the barrier and the casing which produce preferential fractures in the casing along the planes of the detonation wave interactions.

2. The apparatus described in claim 1 wherein said outer casing is spherical in shape and said barrier is spherical and concentric with said casing.

3. The apparatus set forth in claim 2 wherein said barrier is formed from wire mesh.

4. The apparatus set forth in claim 2 wherein said means for detonating the explosive material is disposed at a point in the center of the spherical casing.

5. The apparatus described in claim 1 wherein said outer casing is cylindrical and said barrier is cylindrical and concentric with said outer casing.

6. The apparatus set forth in claim 5 wherein said means for detonating the explosive material is disposed on at least one point on the axis of said cylindrical casing.

7. An apparatus of the class described comprising an outer casing, explosive material in said casing, a wave barrier having generally equally spaced openings and surrounding said explosive material, said wave barrier being in spaced parallel relation to said casing and at a distance therefrom which is substantially equal to the thickness of said barrier, the spacing between said generally equally spaced openings being substantially equal to twice the thickness of said Wave barrier, and means for detonating said explosive material whereby when the resulting detonation wave reaches the wave barrier, parts of the wave pass unhindered through the openings and form a network of equally spaced detonation wave interactions beyond the barrier which produce preferential fractures in the casing along the planes of the wave interactions, thereby producing casing fragments which are substantially equal in size.

8. The apparatus described in claim 7 wherein said outer casing is a surface of revolution and said barrier is equidistant from said casing, and said means for detonating the explosive material being disposed in said casing.

9. An apparatus of the class described comprising an outer casing, expolsive material in said casing, a wave barrier having a plurality of groups of perforations extending therethrough, the spacing between the perforations in any one group different from the spacing between the perforations in any other group, said wave barrier being disposed about said explosive material and in spaced parallel relation to said casing, the thickness of the portion of the perforated barrier containing any one group of perforations equal to one-half the spacing between the perforations in that group and equal to the spacing between that portion of the perforated barrier and the outer casing, and means for detonating said explosive material whereby when the resulting detonation wave reaches the perforated barrier, parts of the wave pass through the perforations and serve as point sources for a network of expanding detonation waves centered around each perforation, said expanding waves interacting with each other so that the waves centered about the perforations in each group reinforce each other along planes of interaction, thereby producing fragments having a size determined by the spacing between the perforations in the group, whereby each group of perforations produce waves which interact with each other to shatter the casing into groups of fragments wherein the size of the fragments in each group is related to the spacing between the perforations in an associated portion of the perforated barrier.

10. An apparatus of the class described comprising an outer casing, explosive material in said casing, a wave barrier having a plurality of groups of openings extending therethrough, the spacing between the openings in any one group different from the spacing between the openings in any other group, said wave barrier encasing said explosive material and in spaced parallel relation to said casing, and means for detonating said explosive material whereby when the resulting detonation wave reaches the barrier, parts of the wave pass through the openings and serve as a point sources for a network of expanding detonation waves centered around each opening, said expanding waves interacting with each other so that the waves centered around the openings in each group reinforce each other along planes of interaction, thereby fracturing the easing into fragments having a size determined by the spacing between the openings in the associated group.

References Cited in the file of this patent UNITED STATES PATENTS 32,702 McIntyre July 2, 1861 1,015,944 Du Pont Jan. 30, 1912 1,211,001 Steinmetz Jan. 2, 1917 2,413,008 Taglialatela Dec. 24, 1946 FOREIGN PATENTS 284,108 Germany May 10, 1915

Claims

1. AN APPARATUS OF THE CLASS DESCRIBED COMPRISING AN OUTER UNITARY CASING OF INTEGRAL NON-SCORED CONSTRUCTION, EXPLOSIVE MATERIAL IN THE CASING, A BARRIER PROVIDED WITH OPENINGS DISPOSED ABOUT SAID EXPLOSIVE MATERIAL AND COMPLETELY ENCASING SAID EXPLOSIVE MATERIAL, SAID BARRIER BEING DISPOSED IN INWARDLY SPACED RELATION TO SAID CASING TO DEFINE A SUBSTANTIALLY CONTINUOUS UNOBSTRUCTED SPACE THEREBETWEEN, MEANS FOR DETONATING SAID EXPLOSIVE MATERIAL, AND THE RESULTING DETONATION WAVE COACTING WITH SAID BARRIER SO THAT WHEN THE DETONATION WAVE REACHES SAID BAR-