GB2284878A - Device for protection against high-velocity destructive weapons - Google Patents

Abstract

The proposed device comprises a capsule (1) whose cavity is packed with an explosive charge (2). Two capsule walls (3, 4) which face each other are constructed as protective plates, and each of the other walls (5) is multi-layered; the ratio of the acoustic impedances of the materials in contiguous layers (6 and 7, 7 and 8, 8 and 9) is not less than 2. <IMAGE>

Description

DEVICE FOR PROTECTION AGAINST HIGH-VELOCITY DESTRUCTIVE WEAPONS The present invention relates to protection of objects against high-velocity weapons and, more specifically, to a device for protection against highvelocity hollow-charge weapons.

The disclosed device can be used to the greatest advantage for protection of objects against hollowcharge ammunition and armor-piercing hard-core shells.

Known in the prior art is a device for protection against high-velocity weapons, in the form of a closed container whose cavity is filled with an explosive (PCTSE\OOI32). Two opposite walls of said container are made as protective plates capable of moving relative to one another.

As a hollow-charge projectile strikes said container, the hollow-charge blast causes detonation of the explosive charge in the container cavity. The gaseous products of detonation produced by explosion set in motion the protective plates which cross the trajectory of the hollow-charge blast and destroy it, reducing its armor-piercing power. Thus, this device is capable of protecting an object against hollowcharge weapons. However, detonation of the explosive charge filling the container cavity can, apart from destroying the hollow-charge blast, act on the adjacent containers. The shock wave produced by the explosion propagates from the center of explosion in all directions. Getting into the explosive charge of the adjacent container, the shock wave can initiate detonation of said charge. Further development of this process may bring about an uncontrollable propagation of detonation to the explosive charges of all containers installed on the protected object. Thus, a single hit of the hollow-charge weapon may destroy all the containers installed on the protected object.

As a result, the object will not only lose its anti-hollow-charge protection but might be damaged by the joint explosion on its surface of a heavy mass of explosives. Similar effect may occur if the container is hit by an armor-piercing hard-core projectile if the explosive charge in the container is sufficiently sensitive for being detonated by such a projectile.

To rule out such unwanted effects, it is suggested that the disclosed device be provided between the adjacent containers with a material effectively damping the parameters of the shock wave. However, said material introduced into the device is, in effect, an additional structural member which complicates the design of the known device. Besides, the use o. f such a material causes the explosive charges of the adjacent containers to be separated from one another by a distance which usually is by far larger than the diameter of the hollow-charge blast and, often, the diameter of the armor-piercing hard-core shells Getting into the partition of said material, the hollow-charge blast of the armor-piercing hard-core shell can penetrate to the protected object without detonating the explosive charges in the containers.

Protection of an object realized by the adovedescribed method is of a discrete nature: well-protected area alternate with weak zones whose area, depending on the thickness of the used material, may run as high as 30% of the entire protected area of the object.

The main object of the present invention resides in providing a device for protection against highvelocity weapons with the walls of the closed container designed so as to reduce considerably the area of weak zones thereby raising the protection level of

the object.

This object is attained by providing a device for protection against high-velocity weapons in the form of a closed container whose two opposite walls have the form of protective plates capable of moving relative to each other while the container cavity is filled with an explosive capable of detonating on being struck by a high-velocity projectile. According to the present invention, each of the remaining container walls is of a multilayer construction, consisting of at least three layers with the relation of acoustic stiffnesses of the materials in the adjacent layers being at least 2.

It is a necessity that the thickness of each layer of said walls be 0,0005-0. 4 the distance between the protective plates.

Selection of the minimum thickness of said walls is governed by the manufacturing conditions of said layers and the necessity to prevent propagation of detonation to the adjacent container. The upper limit of layer thicknesses of said walls is defined on the condition of reliable initiation of the explosive charge.

This design simplifies substantially both the design of the device as a whole and the manufacture of the closed container.

In order to ensure reliable initiation of the explosive charge when the device happens to be hit by a high-velocity weapon, the relation of the masses of explosive substance and inertia binder in the charge be at least 4: 1.

Now the present invention will be described in detail by way of concrete embodiments with reference to the appended drawings in which:

Fig. I is a device for protection against highvelocity weapons according to the invention, longitu dianl section; Fig. 2-same as in Fig. I with a second design version of the closed container, according to the invention.

The device for protection against high-velocity weapons according to the present invention is made as a closed container I (Fig. I) whose cavity is filled with a charge of explosive substance 2.

The container I may have the form of a parallelepiped, prism or cylinder whose two opposite walls are made as protective plates 3,4 capable of moving relative to each other. The other walls 5 of the container I are of a multilayer construction and consist of four layers 6,7, 8 and 9. The minimum number of layers is three. The relation of acoustic stiffnesses of materials in the adjacent layers 6 and 7,7 and 8,8 and 9 is not under 2. The thickness of each layer 6 and 7,8 and 9 of said walls 5 is 0.0005-0. 4 the distance between the protective plates 3,4.

The disclosed device functions as follows.

As the blast of the hollow-charge projectile or an armor-piercing hard-core shell hits the disclosed device, it pierces the protective plate 3 and penetrated into the explosive charge 2, detonating it. Acted upon by the gaseous products of detonation, the protective plates 3,4 start moving in the direction which is close to the normal to the surface of said protective plates 3,4. The moving plates 3,4 cross the trajectory of the high-velocity weapon and, jointly with the expanding gaseous products of detonation of the explosive charge 2, disperse the hollow-charge blast into individual fragments and deflect them from

the initial direction of movement. As a result, the individual fragments of the hollow-charge blast do not get into the bottom of the cavern made in the protected object (not shown) by the preceding portions of the blast. Thus, said cavern does not grow in depth so that the armor-piercing power of the hollowcharge blast diminishes. The impact of the protective plates 3, 4 against the body of the armorpiercing hard-core shell produces micro-and macrodefects therein. The shell acquires an angular rotating speed which affects adversely its armorpiercing power.

Simultaneously with the movement of protective plates 3, 4 the detonating wave propagating through the explosive charge reaches the walls 5 of the container I. The shock wave developing in the internal layer 9 of the wall 5 propagates towards the external surfaces 10 of the wall 5. On its way it crosses successively the boundaries between the layers 9 and 8,8 and 7,7 and 6 made of materials with a different acoustic stiffness. On the interface between the layers, for example when the wave travels from the material with a higher acoustic stiffness (layer 9) to the material with a smaller acoustic stiffness (layer 8) there occurs the so-called"disintegration of explosion"in which a passing shock wave is formed in the material of the layer 8 with a lower acoustic stiffness whereas a relief wave is formed in the material of the layer 9 with a higher acoustic stiffness. The relief wave travels from the interface of the layers 8 and 9 towards the internal surface II of the wall 5, relieving the shock-compressed material of the layer 9 to the initial state.

The shock wave passing through the material of the layer 8 is noted for lower parameters (pressure,

mass velocity) at its front than those at the shock wave front in the layer 9. The difference between the values of parameters at the front of the shock wave falling from more acoustically stiff medium into less acoustically stiff one is proportionate to the relation of acoustic stiffness of media. It has been found experimentally that this relation should be not less than 2. Besides, a drop of parameters at the front of the passing shock wave in the layer 8 is attributed to the irreversible energy losses in the incident shock wave which are encountered inthe process of shock-wave compression of the layer 9.

Further propagation of the shock wave is associated with its crossing the interfaces of the layers 8 and 7,7 and 6 where the above-mentioned process of "disintegration of explosion"is repeated while the parameters at the shock wave front continuous dropping as described above.

Propagation of side relief waves from the surfaces of the wall 5 adjoining the protective plates 3,4 reduces the size of the shock wave front. It is common knowledge that the side relief waves in the multiplelayer walls travel at an angle of about 40-50 deg which larger than said angle in single-layer walls. Thus, as the shock wave travels through the layers 9. 8,7, 6 of the wall 5, both the parameters at the shock wave front and the size of the front proper diminish. As the shock wave reaches the external surface 10 of the wall 5, said wave passes into the same wall of the adjacent container 12 (if any) wherein the shock wave propagates in a similar manner.

As a result of repeated travel across the interface with the above-stated relation of acoustic stiffnesses, of losses for shock-wave compression of material layers of the walls 5, and of the diminished size of the

shock-wave front, the shock wave reaching the explosive substance of the adjacent container 12 loses its capacity of initiating the detonation of said tu explosive even 11 the relation of masses of the explosive even 0 explosive and inert binder in the material of the charge exceeds 4: 1.

Its has been found from experiments that the charges 2 filling the container I in an explosiveinert binder relation below 4: 1 are reliably initiated on being hit with a high-velocity weapon and are not initiated by the effect of the shock wave produced by explosion in the adjacent container 12.

When selecting the thicknesses of the layers 6,7, 8,9 of the wall 5 of the container I one must bear in mind the following points. On the one hand, the minimum thickness of the layers 6,7, 8,9 shall be sufficient for required reduction of parameters of the shock wave created by the detonation of the explosive in the container I. Hence, the minimum thickness of said layers is governed by the dimensions of the container I and characteristics of the explosive 2 (detonation velocity, specific heat of explosion) therein. Besides, the minimum thickness of these layers depends on the practicability of their manufacture.

On the other hand, the maximum thickness of these layers must ensure detonation of at least one of the two adjacent containers I, 12 when the hollow-charge blast or an armor-piercing hard-core shell hits the contact zone of said containers. Hence, the maximum thickness of each of said layers depends on the diameter of the armor-piercing hard-core shell or of hollowcharge blast with due account of natural dissipation of the hollow-charge blast in the region defined by a cone with A solid angle of I-I, 5 deg at the apex (the size of this dissipation zone depends on the distance

between the hollow-charge projectile and the container I). This consideration also holds true for the necessity of contact between the explosive substance 2 and the internal surface II of the wall 5.

On the basis of the above data the thickness of the layers 6,7, 8,9 of the wall 5 is selected from a range of 0.0005-0. 4 of the distance between the protective plates 3, 4. On such instances when the device for protection against high-valocity weapons according to the present invention utilizes the container I with multiple-layer walls 5, as shown in Fig. 2 the latter are formed by collars I3, 14 of the protective plates 3 and 4 the gap between which is filled fully or partly with a nonmetallic, e. g. paint or varnish, material 15, one of said flangings (13) is in contact with the explosive 2.

This design simplifies substantially the manufacture of the container I. The disclosed device with such a design of the container I functions largely on the similar lines with the one described above.

The disclosed device will be used to the greatest advantage in the form of a set of such devices that go to form a reactive armor installed on armored ground objects such as tanks, infantry armored vehicles, armored personnel carriers, self-propelled artillery mounts, building structures, transport vehicles, river and sea craft.

Claims (12)

1. CLAIRS

   I. A device for protection against high-velocity weapons consisting of a closed container (I) whose two opposite walls (3,4) have the form of protective plates capable of moving relative to each other and the container cavity is filled with an explosive charge (2) CHARACTERIZED in that each of the other walls (5) of the container (I) is of a multiple-layer construction comprised of at least three layers (6,7, 8,9) with the relation of acoustic stiffnesses of materials in the adjacent layers (6 and 7,7 and 8, 8 and 0) being not less than 2.
2. 2. The device of Claim I CHARACTERIZED in that the thickness of each layer (6, 7, 8,9) of said walls 5 is 0.0005-0. 4 of the distance between the protective plates (3, 4).
3. 3. The device of Claim I CHARACTERIZED in that in the three-layer construction of said walls (5) each of said walls is formed by the collars (I3, I4) of the protective walls (3,4) the gap between which is filled

   with a nonmetallic material (IS) and one of collars (I3) is in contact with the explosive charge (2).
4. 4. The device as claimed in Claim I CHARACTERIZED in that the relation of masses of the explosive substance and inert binder in the material of the charge (2) is at least 4: 1.
5. 5. A set of devices according to any one of Claims 1-4.
6. 6. The set as claimed in Claim 5 intended for protection of an armored ground object.
7. 7. The armored ground object of Claim 6 which is a tank.
8. 8. The armored ground object of Claim which

   is an infantry armored vehicle or armored personnel carrier.
9. 9. The armored ground object of Claim 6 which is a self-propelled artillery mount.
10. 10. The set of Claim 5 for protection of building structures.
11. II. The set of Claim 5 for protection of river or sea craft.
12. 12. The set of Claim 5 for protection of transport container.