GB2090385A

GB2090385A - Armour plating with a multidirectional structure

Info

Publication number: GB2090385A
Application number: GB8011190A
Authority: GB
Original assignee: Societe Europeenne de Propulsion SEP SA
Current assignee: Societe Europeenne de Propulsion SEP SA
Priority date: 1979-04-10
Filing date: 1980-04-10
Publication date: 1982-07-07
Also published as: FR2494832B1; DE3013698C2; NL8002091A; NL185868B; DE3013698A1; GB2090385B; NL185868C; FR2494832A1

Abstract

Armour plating, specifically for protection of fixed installations, vehicles and personnel against projectiles and the mechanical and physical effects of an explosion, comprises a multidirectional structure (10) of substantially rectilinear rigid components (1,2,3,4) arranged in at least three different directions (e.g. four different directions parallel to the four major diagonals of a cube, in a regular criss-cross pattern) the directions of the components not all being parallel to the same plane and forming between themselves angles of between 30 DEG and 90 DEG . The armour plating is of increased effectiveness against penetration as compared with solid steel, even when constructed with a substantially lower density than steel. The components may be solid or tubular and may include an active material. The space between the components may be filled with a matrix material. <IMAGE>

Description

SPECIFICATION Armour plating with a multidirectional structure This invention concerns armour plating with a multidirectional structure.

To be more precise, the invention covers a new method of producing armour plating, shields or protective screens for the protection of fixed or moving equipment, or of personnel, against, in particular, combat projectiles such as bullets or inert or explosive shells, and specifically those of 'hollow charge' type, that is, fragmentation from such projectiles or from obstacles hit by such projectiles, or fragmentation from other explosive devices such as grenades, mines or torpedoes or as a result of rupture of pressurised vessels. The invention also concerns the protection of equipment and personnel against the mechanism and physical effects of explosions of a pyrotechnical or nuclear origin, such as blast, shock wave, Flash, gamma radiation, neutron flux etc.

One well known means of protection consists in using a shield made of a dense and highly rigid material, such as solid steel, as used for example for the armour plates currently employed to protect armoured tanks, battleships or fixed installations.

Such armour plates, of a purely passive type, can prevent the penetration of projectiles because of their high inertia and dissipate the greater part of the projectile's kinetic energy by plastic deformation.

The effectiveness of this type of plating depends on its thickness. The heavier the projectile to be stopped, and particularly the higher the velocity of the projectile, the greater must be the thickness of the armour. The severest cases of damage known so far are caused by the streams of metal thrown off by hollow charge weapons at a velocity of up to 10000 m/s or by inert projectiles known as 'kinetic energy projectiles or 'darts' with a velocity of up to 2 000 m/s. It is known, for example, that a modern anti-tank weapon with a 105 mm diameter hollow charge projectile can penetrate solid steel armour plating 60 cm thick. To protect a tank effectively aguinst this type of weapon, it would have to be provided with such a weight of inert armour that it would no longer be able to move.

Various solutions have been put forward for increasing the effectiveness of armour plate while yet making its weight and size compatible with the carrying ability of the vehicle to be produced.

For armour plating which has to resist the most lethal projectiles, such as those fired by modern anti-tank weapons, it has been suggested to distribute the weight of the plating using a large number of thin superimposed and independent sheets, to combine in the armour plating several grades of metal such as steels and light alloys and possibly to insert between these metal sheets one or more types of material whose physical and mechanical properties are different from those of the metals, such as, for example, ceramic or plastic materials.

In the case of shields which are specifically designed to stop inert projectiles of relatively small calibre, such as the bullets in pistols, rifles or machine guns, or various types of fragmentation, it is known to use mainly a laminated type composite material made up of superimposed layers of material based on natural or synthetic fibres of high rigidity, the layers being impregnated and bonded together with a thermosetting type of resin. The effectiveness of such shields comes from their ability to dissipate the kinetic energy of the projectile through the breakdown of the laminations of the composite material in an extensive area around the point of impact.The surfaces of some versions of these shields are covered with plates made of dense ceramic material such as sintered and alumina the effect of which is to blunt the nose of the projectile and possibly cause it to rupture, thus reducing its penetrative power. Such shields are used for example to protect aircraft or helicopter pilots. They are then built into the pilot's seat in the cockpit.

Finally, there exists another type of protective shield designed for the individual protection of personnel, known as the 'bullet-proof waistcoat'.

This must be light and flexible enough not to hamper the movements of the person wearing it. One of the most recent and most efficient designs consists essentially of a very thick and compact material with a three-directional structure made from a highly rigid textile fibre. This material is normally used as it is without being impregnated.

The purpose of this invention is to provide armour plating which can be used for the protection of fixed installations or vehicles against all the kinds of attach to which they may be exposed and particulaly from anti-tank weapons, and also for the protection of individuals against light firearms or various kinds of splinters.

This purpose is achieved by armour plating which, in accordance with the invention, consists at least in part of a multidirectional structure formed by approximately rectilinear rigid components arranged in at least three different directions in a regular crisscross pattern, the directions of the components not all being parallel to the same plane but forming angles between themselves of between 30 and 900.

The phrase "regular criss-cross pattern" is meant here to describe a relatively regular arrangement in space of components lying in the same direction and a relatively regular distribution in the structure between the components of the various lines of direction.

The said structure is preferably compact, i.e. the ratio between the space occupied by the components and the apparent space in the structure is high as possible for components of a given shape, dimensions and direction.

According to a preferred particular form of embodiment of the invention the multidirectional structure is made up of straight rigid components arranged in 4 different directions.

The components can have a cross-section of arbitrary shape, although it is generally a circle or a polygon.

The diameter of the cross-section of the components or of the circle circumscribed by this section can vary depending on the proposed purpose of the armour plating and the nature of the material constituting the components. This diameter is generally between a fewtenths of millimetres and several centimetres, e.g. between approximately 0.5 mm and 5 cm.

In the longitudinal direction the shape and dimensions of the cross-section of the components can be constant or variable.

The components can be solid rods or bars.

It is also possible to use tubular components which can be empty orfilled with a different material, or possibly with an active material. An active material means a material which can react violently either by itself, such as an explosive, or with another constituent item of the armour plating or with a product from a projectile which has hit the armour plating. Typical possible combinations are ammonium nitrate and magnesium or nitrogen peroxide and titanium.

The material for the components of the structure is chosen in relation to the purpose of the armour plating. It may be a metal, such as steel or tungsten, a ceramic, glass, wood, a plastic or a composite material, or an active material as described above.

To make the armour plating, the structure can be used as it is. Its rigidity is then ensured by fixing on a support in the form of a plate or sheet the ends of the components defining the side of the structure adjacent to this support, or by bonding the components at the points where they cross each other. Bonding can be effected by means of an adhesive, e.g. by immersing the structure in a polymerisable resin, and then removing it and drying it before the resin is polymerised.

The structure can also be combined with a filler material, or matrix, which fills the spaces between the structural components. This filler material can be metal, ceramic, glass, cement, a plastic or rubbery material, a composite or an active material.

Different materials can be used in one and the same armour plating for the components of the structure, orforthe matrix, if used, and the components can have different shapes and dimensions in different parts of the plating. The materials, shapes and dimensions can be varied in a uniform or non uniform manner, e.g. as between one side and another of the armour plating. Thus, the plating can be composed of several layers having different structures.

Or again, it is possible to alternate layers with a multidirectional structure in accordance with the invention and layers constituted in a different manner, e.g. conventional solid plates.

As indicated above, in the preferred form of embodiment of the invention the multidirectional structure constituting the basis of the plating consists of the regular compact criss-crossing of four sets of rectilinear components arranged in four directions in space. A mutual arrangement identical with that of the components comprising the reinforcing structure for composite materials described in the UK patent 1 509 208 corresponding to the US patent 4 168337 can be used for the components.

This structure is commonly known as 4D.

in the 4D structure when constructed in its ba lanced form, the four directions follow the four major diagonals of a cube so that each of the directions forms an angle of 70" 1/2 with each of the other three directions.

This preference for the 4D structure must not be assumed to be exclusive. The multidirectional structure formed by rigid components constituting the basis of the armour plating can be a structure which comprises only three groups of components, known as 3D, or a structure comprising more than 4 groups of components, such as that described in the UK patent application 14269 filed on 24.4.79 corresponding to the US patent application 22 171 filed on 20.3.79 or in the UK patent application 17 212 filed on 17.5.79 corresponding to the US patent application 22 195 filed on 20.3.79, or a structure derived from the 4D structure by gradual~curving-in of the direction of the components, such as that described in the UK patent application 09 098 filed on 15.3.79, corresponding to the US patent application 19 571 filed on 12.3.79.In each case, the structure is produced from a regular criss-crossing of appreciably rectilinear rigid components.

The following examples illustrate in a non restrictive manner various forms of construction of armour plating in accordance with the invention.

Reference is made to Figures 1 to 3 illustrating a form of construction of a multidirectional structure for armour plating in accordance with the invention and two arrangements of this structure for test purposes.

Example 1 The armour plating is constructed by means of the balanced 4D structure 10 shown in Figure 1. This structure consists of rods 1,2,3,4 lying parallel to the four major diagonals of a cube. The rods arranged in different directions form angles of 700 1/2.

This compact balanced 4D structure was constructed using metal rods of circular cross-section 2 mm in diameter in Stub steel. It had a density of 5 300 kg/m3. The structure was subjected just as it was, i.e. without a matrix, to a hollow charge penetration test to evaluate its effectiveness as compared with standard armour plating made of solid steel with a density of 7 800 kg/m3.

The penetration test consists in subjecting the armour plating under test to an attack directed perpendicularly to its surface by a 62 mm hollow charge the front face of which is placed 12.4 cm from the surface of the armour. In such conditions solid steel can be penetrated to a depth of 40 cm.

For this test, the 4D structure, which was only 5 cm thick, was placed in front of a block of solid steel 20 (Figure 2) used to measure the residual energy of the stream of metal from the hollow charge 21 in the event of complete penetration of the 4D structure.

The orientation of the structure was such that the direction of two of the four groups of metal rods was parallel to the surface exposed to the hollow charge, and the directions of the other two groups formed angles of 54 3/4 with this surface.

Afterthe charge was fired the 4D structure was found to have been penetrated completely, the block of solid steel being penetrated to a depth of 23.5 cm.

This result showed that the 5 cm thick armour plating with a 4D structure was as effective as a 16.5 cm thick solid steel plating and that consequently it gave a 70% saving in thickness compared with the solid steel, with, in addition, because of its lower density, a surface mass saving of 79%. The surface mass of armour plating is the ratio between its density and its thickness, or, which amounts to the same thing, the mass of armour plating required per unit area to ensure protection.

Example 2 A compact balanced 4D structure was constructed using mild steel bars with a circular cross section 8 mm in diameter. It had a density of 5300 kg/m3. This structure was immersed in a liquid epoxy resin which was then polymerised, thus forming the matrix of the composite armour plating material which then had a density of 5 650 kg/m3. A block of this composite material was subjected to the penetration test using a 62 mm hollow charge.

For this test the structure 10 was oriented so that the four groups of bars were inclined at the same angle with relation to the front surface of the block, the directions of the four groups thus forming angles of 35 1/4 with this surface (Figure 3).

In such conditions this composite armour plating material gave an 18% saving in surface mass compared with solid steel.

Example 3 A compact balanced 4D structure was constructed using tungsten bars with a circular cross-section 7 mm in diameter. After insertion of an epoxy resin matrix, this composite armour plating material had a density of 13400 kg/m3.

A block of this material was subjected to the penetration test using a 62 mm hollow charge. For this test, the structure was arranged in exactly the same manner as for the block in Example 2.

In such conditions this composite armour plating material gave a 42% saving in thickness as compared with solid steel, but, because of its higher density, the surface mass was the same as that of the steel plating.

Example 4 A compact balanced 4D structure was constructed using glass bars with a circular cross-section 7 mm in diameter. After the insertion of an epoxy resin matrix this composite armour plating material had a density of 2 000 kg/m3.

Two penetration tests with a 62 mm hollow charge were carried out on this material.

For the first test the structure was arranged in a manner identical to that used for the block in Example 1.

In such conditions this composite armour plating material gave a surface mass saving of 78% as compared with solid steel, although, because of its much lower density, the saving in thickness was only 13%.

For the second test the arrangement of the structure was the same as that for the block in Example 2.

In these conditions the saving in surface mass and the saving in thickness was respectively 78% and 13%, that is, the same as in the firsttest.

Example 5 For a material more specifically designed for protection against the effect of the X flash resulting from a nuclear explosion a composite carbon-carbon material with a 4D structure was used. This material had a density of 2 000 kg/m3, being composed of small 1 mm diameter pultruded rods and made more dense by impregnation and carbonisation of tar under pressure. The composite was subjected to very violent shock waves produced by explosives which simulated the stressing which the material would undergo as a result of the effect of an Flash.

This composite material showed exceptionally high strength as compared with the other materials envisaged for the same purpose.

Example 6 For the protection of personnel against bullets and fragmentation splinters a multidirectional structure with n different directions (nD structure), preferably the 4D structure or the 6D structure shown in Figure 6 in the patent application 79-14269 quoted above, was used. This structure can be constructed with small rods of a diameter of 1 mm or less, made from a unidirectional composite material and immersed in an epoxy resin or elastomer matrix. The structure can be covered with a ceramic material.

Claims

1. Armour plating for protection specifically against projectiles and the mechanical and physical effects of an explosion, characterised in that it comprises, at least in part, a multidirectional structure consisting of appreciably rectilinear rigid components arranged in at least three different directions in a regular criss-cross pattern, the directions of the components not all being parallel to the same plane and forming between themselves angles of between 300 and 900.

2. Armour plating according to Claim 1, characterised in that the structure is compact.

3. Armour plating according to either of the Claims 1 and 2, characterised in that the multidirectional structure is made up of rectilinear rigid components arranged to lie along four different directions.

4. Armour plating according to Claim 3, characterised in that the rectilinear rigid components are arranged in directions which are parallel to the major diagonals of a cube.

5. Armour plating according to any of the preceding claims, characterised in that a matrix fills the spaces between the components of the multidirectional structure.

6. Armour plating according to any of the preceding claims, characterised in that the components of the structure have a circular or polygonal crosssection.

7. Armour plating according to any of the preceding claims, characterised in that the diameter of the circle circumscribed by the cross-section of the components in the structure is between 0.5 mm and 5cm.

8. Armour plating according to any of the preceding claims, characterised in that the structure comprises tubular components.

9. Armour plating according to Claim 8, characterised in that the tubular components are filled with a material which is diff se'rent from the material of which they are made.

10. Armour plating according to Claim 9, characterised in that the said different material is an active material.

11. Armour plating according to any of the preceding claims, characterised in that it comprises several different layers at least one of which consists of the said multidirectional structure.

12. Armour plating constructed according to Example 1.

ample Armour plating constructed according to Ex ample Armour ample Armour plating constructed according to Ex ample Armour ample Armour plating constructed according to Ex ample Armour 16. Armour plating constructed accordingto Ex- 16. Armour plating constructed according to Ex ample Armour plating constructed according to Ex ample Armour ample 6.

18. Armour plating according to claim 1, constructed substantially as hereinbefore described.

New claims or amendments to claims filed on 1 Mar 1982 Superseded claims All New or amended claims

1. Armour plating for protection specifically against projectiles and the mechanical and physical effects of an explosion, characterised in that it comprises, at least in part, a multidirectional structure consisting of rectilinear rigid components arranged to iie along at least four different directions in a regular criss-cross pattern, but at least three of said at least four different directions of the compo nents not all being parallel to the same plane and said at least four different directions forming between themselves angles of between 300 and 900.

2. A moving or stationary object, such as a tank, battleship, building structure or article of equipment, which is protected, at least partially, by armour plating providing protection against projectiles and explosive devices, characterised in that the armour plating comprises, at least in part, a multidirectional structure consisting of rectilinear rigid components arranged to lie along at least four different directions in a regular criss-cross pattern, but at least three of said at least four different directions of the compo nents not all being parallel to the same plane and said at least four different directions forming between themselves angles of between 300 and 900.

3. An article of apparel including means providing protection for at least part of the wearer against injury by light firearms and explosive devices, characterised in that the protection means compris es, at least in part, a multi-directional structure consisting of rectilinear rigid components arranged to lie along at least four different directions in a regular criss-cross pattern, but at least three of said at leastfourdifferentdirections of the components not all being parallel to the same plane and said at least four different directions forming between themselves angles of between 300 and 900.

4. The invention according to any one of the preceding claims, characterised in that the structure is compact.

5. The invention according to any one of the preceding claims, characterised in that the rectilinear rigid components are arranged in directions which are parallel to the major diagonals of a cube.

6. The invention according to any one of the preceding claims, characterised in that a matrix fills the spaces between the components of the multi directional structure.

7. The invention according to any one of the preceding claims, characterised in that the compo nents of the structure have a circular or polygonal cross-section.

8. The invention according to any one of the preceding claims, characterised in that the diameter of the circle circumscribed by the cross-section of the components in the structure is between 0.5 mm and 5 cm.

9. The invention according to any one of the preceding claims, characterised in that the structure comprises tubular components.

10. The invention according to claim 9, characte rised in that the tubular components are filled with a material which is different from the material of which they are made.

11. The invention according to claim 10, char acterised in that the said different material is an active material.

12. The invention according to any one of the preceding claims, characterised in that it comprises several different layers at least one of which consists of the said multi-directional structure.

13. Armour plating constructed according to Ex ample 1.

14. Armour plating constructed according to Ex ample Armour ample Armour plating constructed according to Ex ample Armour ample3.

ample Armour 17. Armourplating constructed according to Ex- ample Armour ample Armour plating constructed according to Ex ample Armour ample 6.

19. Armour plating according to claim 1,con structed substantially as hereinbefore described.