IL109223A - Reactive armor against kinetic projectiles - Google Patents

Description

109223/2 A reactive armor against kinetic projectiles Rafael Armament Development Authority iitt n¾7 tsn ron»a n Ltd.

The Inventors: Benjamin Keren •pp γ η Ron Genussov Dan Yaziv Nir Gov TO C. 091600 FIELD AND BACKGROUND OF THE INVENTION The present invention is in the field of armored land vehicles and concerns means for the protection of such vehicles against armor-piercing kinetic long-rod projectiles.

The technology of armor-piercing kinetic long-rod projectiles, usually of tungsten alloys, is rapidly developing. Nowadays armor-piercing kinetic rod projectiles are already capable of piercing 400 mm of steel armor and it is expected that by the end of the decennium the steel armor-piercing capability of such projectiles will increase to 700 mm. Most of the existing armored land vehicles cannot withstand such threat and need add-on armor for better protection. Such add-on armor should give adequate protection without increasing the total weight of the vehicle to a point where it is no longer manageable.

To date, there are not known any adequate add-on protection means against armor-piercing kinetic long-rod projectiles and it is the object of the present invention to provide such means. - 2 - 109223/2 BRIEF DESCRIPTION OF THE INVENTION In the following description and claims the term "striker" will be used for a metal panel that is hurled against an oncoming kinetic, long-rod projectile, and the term "cluster of strikers" will be used to denote two or more juxtaposed or otherwise "cluster of strikers" will be used to denote two or more juxtaposed or otherwise agglomerated strikers, placed on an explosive substrate.

In accordance with the present invention there is provided a modular reactive armor unit for making an add-on reactive armor on top of a passive armor for protection against kinetic long-rod projectiles of the armor-piercing type, comprising: a casing with rear and fore ends; at least one cluster of strikers comprising at least two strikers; high-velocity long-rod projectile, signal generating sensor means near the fore end of the casing; and activator means for bringing about in response to signals from said sensor means a properly timed detonation of the explosive substrate of said at least one cluster of strikers.

Preferably the reactive armor unit according to the invention has an identification capability for distinguishing between relevant and irrelevant threats, whereby the activator means are triggered only in case of a positive identification. If desired, the said high-velocity long-rod projectile sensor means located near the fore end of the casing may also serve as identification means to determine whether an oncoming object is a high- velocity long-rod projectile or not.

In accordance with one embodiment of the invention the sensor means and/or identification capability is a ferro-electric generator activated directly by the propagating Shockwave generated by an oncoming armor-piercing projectile.

By another embodiment the sensor means and/or identification capability is an electro-optical device comprising an array of photodiodes and one or more light sources, which device determines the length, velocity, location and timing of an oncoming threat.

Alternatively, the identification and sensing functions may be separated and identification may, for example be by way of a physical barrier which fends off irrelevant threats such as small firearm projectiles and shrapnell.

Signal generating sensor means of the kind used in accordance with the present invention are commercially available and need therefore not be described. Likewise, electronic devices for use as activator means in the performance of the present invention in association with the said sensor means are also known per se and any known device, suitably dimensioned, that is capable of responding to a signal generated by a sensor and of calculating the time delay for such a response, can be used.

If in operation where an oncoming projectile is identified as a relevant threat, i.e. as a high-velocity long-rod projectile, the detonator is initiated by a signal from the activator means which in turn is triggered off by a signal from the sensor means at proper timing for the strikers of each cluster to be hurled against the projectile so that the latter is hit by several strikers almost simultaneously. As a result, in a first phase the projectile is fissured at several zones and in a second phase is impacted at several locations whereupon it is broken up into a plurality of fragments each of which is deflected from the original trajectory in consequence of the momentum created by the impact. As a result, there is formed a beam of fragments which hit the target in a wide spread and the total depth of penetration into the armor of the deflected and spread short fragments is only a fraction of the depth of penetration of the original long-rod projectile, had it not been intercepted.

The cluster-forming strikers in a reactive armor unit according to the invention may be single bodies or two-body assemblies. In either case several clusters constituting strikers may be juxtaposed on one face of the explosive substrate, or be otherwise agglomerated, e.g. by being placed on two opposite faces of the explosive substrate. If desired the explosive substrate may be mounted on a carrier plate. Alternatively, clusters constituting strikers may be mounted on the inner face of any of the walls of the casing. By still another configuration, two or more strikers are placed vertically one above the other.

For producing a reactive add-on armor for defeating kinetic long-rod projectiles in accordance with the invention, a plurality of modular reactive armor units of the kind specified are mounted on the outer side of a regular passive armor of an armored vehicle so as to suitably cover sensitive regions thereof. There may be several types of modular units so as to make them adaptable for mounting on various types of armored vehicles and on different regions of a given vehicle.

The invention also provides an armored vehicle such as a battle tank, a personnel carrier and the like, fitted with an add-on armor made of modular reactive armor units of the kind specified.

DESCRIPTION OF THE DRAWINGS For better understanding the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a perspective view of a section of an armored vehicle fitted with modular add-on reactive armor units according to the invention with one of the units partly broken open; Fig. 2 is a perspective view of one form of a cluster of strikers according to the invention; - 5 - 109223/3 Figs. 3A and 3B diagrammatically illustrate the mechanism by which a cluster of strikers defeats a kinetic long-rod penetrator, in accordance with the teachings of the invention; Fig. 4 shows several phases in the mechanism by which a kinetic long-rod projectile is broken up into fragments, in accordance with the teachings of the present invention; Figs. 5 to 7 illustrate several embodiments of strikers for incorporation in a unit according to the invention; and Figs. 8 to 11 show several cluster configurations.

DESCRIPTION OF SPECIFIC EMBODIMENTS Referring first to Fig. 1, there is shown a segment of a basic passive armor plate 1 and three identical, long-rod projectile defeating reactive armor units 2 according to the invention mounted thereon. As shown, the units are mounted with the aid of holding and supporting members such as profiles 3 and 4, beams 5 and panels 6, 7 and 8. Each unit 2 has a fore end 9 and a rear end 10.

As shown each unit 2 comprises at its fore end 9 an electric break screen serving as identifier-sensor device 1 1. Inside unit 2 at the middle thereof, there is mounted horizontally a symmetric double sided cluster of strikers 12. The cluster consists of an explosive substrate 13 sandwiched between two rows of strikers 14 and 15.

The unit further comprises near the rear end 10 an electronic activation device 16 suitably linked to the identifier-sensor device 1 1 and further linked to a detonator (not shown in Fig. 1).

The identifier-sensor device 11, the clusters of strikers 13, the electronic activation device 16 and the associated detonator means form together the long-rod projectile defeating system. - 6 - 109223/2 There is further shown in Fig. 1 an oncoming armor-piercing long-rod projectile 18 which is assumed to be intercepted by the identifier-sensor device 11 and thereupon to cause the activation device 16 to initiate, after a calculated delay, the detonation means whereupon the strikers 14 and 15 of the cluster are hurled.

Attention is now directed to Fig. 2 which shows one embodiment of a cluster of strikers for use in a reactive armor unit according to the invention. As shown, the unit comprises a plurality of strikers 20 of wedge-shaped profile, mounted on a carrier plate 21 with the interposition of an explosive substrate body 22 which has a tongue 23 emerging out of the cluster and carrying a detonator 24. The strikers 20 are held within a frame constituted by a fore frame member 25, a rear frame member 26 and two lateral frame members 27, 28. Upon initiation of the detonator 24, the tip of the explosive tongue 23 is detonated and the detonation wave spread along the explosive body 22 from the rear to the fore end whereupon the strikers 20 are successively hurled, the rearmost striker being hurled first and the foremost last.

The mechanism by which a cluster of strikers according to the invention defeats an armor-piercing kinetic, long-rod projectile will now be explained with reference to Figs. 3 A, 3B, and 4. Turning first to Fig. 3 A, there is shown a cluster 30 of strikers 31 associated with an explosive substrate 33 mounted on a carrier plate 34 and having a tongue 35 carrying a detonator 36. Cluster 30 is assumed to be located within a reactive armor unit according to the invention such as, for example, unit 2 in Fig. 1, which in turn is assumed to be mounted in front of an armor plate 37. Essentially the cluster 30 is of a similar design as that shown in Fig. 2, the holding frame not being shown here for the sake of clarity of illustration. As illustrated in Fig. 3B, a kinetic, long-rod projectile 38 that penetrated into the unit and which was positively identified by the sensor device to be armor piercing, causes the activation device to initiate the detonator 36 after a calculated time delay. Upon such initiation, the explosive substrate body 33 is detonated at tongue 35 and in consequence of the forward spreading detonation wave in the explosive substrate, strikers 31 are successively hurled with the rearmost striker being hurled first and the foremost last. The so-hurled strikers 31 intercept and hit the projectile at several spaced zones along its length. As a result of the impact the projectile is first fissured and then fragmented and the various fragments are deflected and spread. In consequence, the total depth of penetration of the deflected and spread short fragments into the armor plate 37 is only a fraction of the depth of penetration of the original projectile had it not been intercepted.

The mechanism of interaction in accordance with the present invention between strikers and a long-rod projectile is diagrammatically shown in Fig. 4. In this illustration each striker is assumed to consist of two constituent parts as shown in Fig. 6 and described below with reference thereto: a fast, narrow, thin-edged constituent to be referred to as "breaker striker", which hits the projectile first and causes fissuring at several zones, and a second, larger, thicker and slightly slower constituent to be referred to as "deflector striker", which causes fragmentation and deflection.

As shown, the profile of the breaker striker 43 is, upon launching, deformed into concave shape. Due to the wedge-shape profile, the hurled breaker striker is tilted with the narrow edge up as shown in Fig. 4(a), and as a result projectile 39 is first hit by the narrow edge of the break striker as shown in Fig. 4(b). This first impact causes a fissure of projectile 39 as shown in Fig. 4(c) where, for the sake of clarity of illustration, the break striker 43 is not shown.

There now follows impact of the already cracked projectile by the deflector striker 44 which causes further fragmentation and deflection as shown in Figs. 4(d), 4(e) and 4(f).

A similar chain of events is caused by each and every one of the hurled pairs of strikers 43, 44 that successively hit projectile 39 and hence the resulting fragmentation and spread as shown in Fig. 3.

The foregoing description with reference to Fig. 4 highlights the two-impact principle underlying the present invention, according to which an oncoming long-rod projectile is hit twice at each of several zones, the first impact causing in each zone a fissure and the second one completing the fissure to full fracture and causing fragmentation and deflection of the fragments. The two-impact modality may be achieved by means of a suitably shaped single-body striker of the kind diagrammatically shown in Figs. 2 and 3 or alternatively with two-body striker assemblies as described with reference to Fig. 4.

Attention is now directed to Figs. 5 to 7 which show three different embodiments of an striker according to the invention designed for achieving the two-impact modality of operation.

Referring first to Fig. 5 there is shown an striker 40 with a wedge-shaped profile resting on an associated explosive substrate 41 mounted on a carrier plate 42, the explosive substrate and carrier plate being common to all strikers of the cluster. The hurled striker 40 is shown on the right hand side of Fig. 5 and the arrows in front and at the rear signify a velocity differential as a result of which the striker is tilted with the narrow edge up which accordingly hits first the intercepted projectile, and this is followed by an impact of the main body portion of striker 40.

Fig. 6 shows a two-part striker embodiment of the kind that was assumed to have been used in the diagrammatic break-up model shown in Fig. 4. As shown, each striker assembly comprises a first, wedged profiled breaker striker 43 juxtaposed to a second, deflector striker 44 which is essentially prismatic with a bevelled front portion 45. The two juxtaposed constituent strikers 43, 44 are located on top of an explosive substrate 46 - 9 - 109223/2 which in turn rests on a carrier plate 47. Upon being hurled the two strikers 43 and 44 proceed as two separate entities with the first, breaker striker 43 flying ahead and impacting on the missile first, to be followed by an impact by the second, deflector striker 44 and in this way the two-impact modality is achieved. Here again the vertical arrows show the velocity differential. As further shown, upon being hurled both constituent strikers 43 and 44 are slightly deformed into concave shape.

In the embodiment of an striker assembly of Fig. 7, a first, thin, break striker 48 with associated thin explosive substrate 49 rests on a second, thicker deflector striker 50 with associated thick explosive substrate 51 mounted on a carrier plate 52. Upon being hurled, strikers 48 and 50 fly separately and the two-impact modality is achieved, essentially similar as with the embodiment of Fig. 6, the vertical arrows again signifying the velocity differential. Here, the strikers 48 and 50 are deformed upon launching into a convex shape.

Figs. 8 to 11 show four different configurations of striker clusters forming part of long-rod projectile defeating systems in reactive armor units according to the invention. In all four Figures the remaining components of the defeating system are not shown.

Turning first to Fig. 8, there is shown a double-sided cluster device similar to that of Fig. 1. As shown, the two rows 55 and 56 of strikers 57 and 58 are mounted on the two sides of an explosive substrate body 59 having an emerging tongue that carries a detonator 60.

In the embodiment of Fig. 9, the cluster 62 of strikers 63 and 65 is broadly speaking L-shaped with each striker 63 being mounted on an explosive substrate 64 and each striker 65 on an explosive substrate 66, the explosive substrates 64 and 66 being suitably attached to the respective sidewalls. As is further shown, the explosive substrate 64 has a tongue 67 bearing a detonator 68 and likewise the explosive substrate 66 has a tongue 69 bearing a detonator 70.

The cluster of Fig. 10 is of a three-dimensional configuration with a first striker 72 attached to a first sidewall of the casing with the interposition of an - 10 - 109223/2 explosive substrate 73; a second striker 74 attached to a second sidewall with the interposition of an explosive substrate 75; a third striker 76 attached to the bottom wall of the casing with the interposition of an explosive substrate 77; and a fourth striker 78 attached to the top wall of the casing with the interposition of an explosive substrate 79.

Finally, in the embodiment of Fig. 11 the cluster comprises three double-sided striker assemblies 81, 82 and 83 vertically superimposed in the manner shown, each assembly comprising an explosive substrate sandwiched between two striker bodies. Thus, in assembly 81 an explosive substrate 84 is sandwiched between strikers 85 and 86; in assembly 82 an explosive substrate 87 is sandwiched between strikers 88 and 89; and in assembly 83 an explosive substrate 90 is sandwiched between strikers 91 and 92.

In Figs. 8 to 11 the manner in which the various striker bodies and clusters are mounted within the casings is not shown. These are trivial matters that can readily be solved by any average technician.

It should be noted that the cluster configurations illustrated and described herein are merely some representative examples and that other configurations are conceivable. Furthermore, while in the embodiment of the invention specifically described hereinbefore the detonator such as any of detonators 24 in Fig. 2, 36 in Fig. 3A, 60 in Fig. 8 and 68 and 70 in Fig. 9 are all located near the rear end, it may also be located elsewhere, e.g. near the fore end.

The materials from which the strikers according to the invention are made, their size and shape are selected by the designer in dependence i.a. on the nature of the expected threat and the type of vehicle that is to be protected. For example, it has been found in accordance with the invention that for defeating a long-rod tungsten projectile of 25 mm diameter and a speed of 1.46 mm/msec, clusters of two-body strikers of the kind shown in Fig. 6 can be used being made of steel alloy 4130 and having the following characteristics: i) Breaker striker size - 4 mm thick, 30 mm wide velocity - 1.2-1.4 mm/msec. slant relative to the projectile: 40-45° ii) Deflector striker size - 8 mm thick, 60 mm wide velocity - 0.9-1.2 mm/msec. slant relative to the projectile: ± 10° Simulation experiments performed in accordance with the present invention have shown that, on the basis of the teachings of the present invention a long-rod armor-piercing projectile can be successfully intercepted within the range of about 50 cm away from the armored vehicle. Interception and deflection of a kinetic projectile at such short range is unique and has never been achieved before and it is due to this unique feature that it has become possible for the first time in accordance with the present invention to defeat a kinetic, long-rod, armor-piercing projectile by means of a reactive add-on armor.

Moreover, similar experiments demonstrated that when a shaped-charge jet is intercepted by several strikers, it is defeated completely and does not reach the target.

Claims (20)

CLAIMS:

1. A modular reactive armor unit for making an add-on reactive tors; , high- velocity long-rod projectile, signal generating sensor means near the fore end of the casing; and activator means for bringing about in response to signals from said sensor means a properly timed detonation of the explosive substrate of said at least one cluster of strikers.

2. A reactive armor unit according to Claim 1, wherein the said signal generating sensor means also serve for threat identification.

3. A reactive armor unit according to Claim 1, comprising separate threat identification means.

4. A reactive armor unit according to Claim 3, wherein said threat identification means is a physical barrier capable of fending off irrelevant threats.

5. A reactive armor unit according to Claim 3, wherein said threat identification means is a ferro-electric generator activated directly by the propagating Shockwave generated by an oncoming armor-piercing projectile.

6. A reactive armor unit according to Claim 3, wherein said threat identification means is an electro-optical device comprising an array of photodiodes and one or more light sources.

7. A reactive armor unit according to any one of Claims 1 to 6, wherein each of the clusters constituting strikers is a single body.

8. A reactive armor unit according to Claim 7, wherein the single body striker has a wedge-shaped profile.

9. A reactive armor unit according to any one of Claims 1 to 6, wherein each of the clusters constituting strikers is a two-body assembly.

10. A reactive armor unit according to Claim 9, wherein two constituent strikers are juxtaposed on one face of an explosive substrate.

11. A reactive armor unit according to Claim 10, comprising a first, smaller and a second, larger constituent striker.

12. A reactive armor unit according to Claim 11, wherein said first, smaller constituent striker has a wedge-shaped profile.

13. A reactive armor unit according to Claim 9, wherein said two-body assembly has a layered structure in which first and second constituent strikers alternate with first and second explosive substrates.

14. A reactive armor unit according to any one of Claims 1 to 13, wherein the strikers are mounted in a row on a carrier plate with the interposition of an explosive substrate.

15. A reactive armor unit according to any one of Claims 1 to 14, wherein each of the clusters of strikers are double-sided symmetric assemblies comprising an explosive substrate sandwiched between two rows of clusters.

16. A reactive armor unit according to any one of Claims 1 to 14, wherein the clusters of strikers are mounted on the inner face of any of the walls of the casing.

17. A reactive armor unit according to any one of Claims 1 to 14, wherein at least two cluster forming strikers are placed vertically one above the other.

18. An armored vehicle fitted with an add-on armor against kinetic, long-rod projectiles, made of modular reactive armor units according to any one of Claims 1 to 17.

19. An armored vehicle according to Claim 18, being a battle tank.

20. An armored vehicle according to Claim 18, being a personnel carrier. 91600spc.MC/prg/03.04.1994