FR2824631A1 - Protection system for protecting armoured vehicles against sub-calibre piercing projectiles comprises an outer ceramic plate, inclined steel plates and inner plate of ductile material - Google Patents

Abstract

The protection consists of an outer alumina or silicon carbide plate (1) 15 - 30 mm thick. An aluminium honeycomb panel (2) 8 - 12 mm thick is joined to a metal plate (3). Inside this assembly is a series of inclined steel plates (4) of very high density, set at 65 to 75 deg to the perpendicular and separated by an air gap (5) of 50 mm, and an inner plate (6) of a ductile material. The inner plate can be of steel 15 - 20 mm thick or aluminium 35 - 45 mm thick. The various components of the armour can be joined by welding, screws, a sliding system or hinges, and attached to a vehicle by lugs and slots.

Description

from which the rod (t) is engaged.

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  The invention relates to a shield for protection against

  kinetic piercing projectiles.

  The term kinetic projectile piercing means a projectile comprising an under-calibrated heavy bar launched by a sabot and whose speed in flight is greater than 1000 m / s. More particularly, the armor according to the invention is intended for the protection of armored vehicles against medium caliber sub-caliber projectiles with an alloy core

of tungsten.

  A medium caliber projectile is a projectile whose

  diameter is between 20 and 40mm.

  These projectiles are characterized by great compactness and very high hardness, which makes their splitting difficult. In known manner, protection against medium caliber projectiles can be carried out according to two methods: - by erosion or rupturing of the projectile using hard material of the ceramic type, - by deflection or rupture of the projectile at l using a double-walled system made up of the association of

  2 metallic thicknesses separated by an air space.

  The first layer favors the rejection of the projectile's core, the air space favors the deflection of the fragments of the projectile and the second layer serves to

  recover the fragments of the projectile.

  French patent 2,703,444 discloses an armor against perforating kinetic projectiles intended to equip a land vehicle and constituted by a tenacious steel bearing structure provided with recesses in the form of cassettes in which are inserted plates of extremely hard material such as very hard steel or ceramic. This structure is especially effective against projectiles from

small caliber.

  The physical phenomenon involved is the rupture of

  projectiles in contact with the filling material.

  European patent 0041271 describes a low mass shielding against kinetic energy projectiles intended to equip vehicles. It consists of a metal structure containing recesses in the form of cassettes in which bars of hard material (for example ceramic) are inserted which are mutually parallel and embedded in a matrix of elastomeric material. This structure makes it possible to limit the transmission of shock waves between the ends of adjacent bars when the projectile breaks on

  bars and gives it a multi-shot capacity.

  As before, the physical phenomenon involved is the rupture of the projectile in contact with the bars of hard material. French patent 2,712,078 relates to a multilayer armor of reduced surface density for protection against projectiles with high kinetic energy and which consists of an outer armor separated from a flash trap, in particular by an air space. The external shielding consisting of an external steel plate, an aluminum plate, a ceramic layer and a steel plate causes fragmentation in small pieces of the body of the projectile. The splinter trap comprising a steel plate, an aluminum plate and a layer of laminate makes it possible to recover the degraded projectile and slowed down in the meantime by the air space. Efficiency is optimal for a

high incidence of the projectile.

  The physical phenomena involved are the erosion of the projectile on the ceramic and the recovery of the projectile

degraded on the splinter trap.

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  The object of the present invention is to obtain a shielding of low mass and reduced dimensions for an efficiency

  maximum at low incidence of the projectile.

  The projectiles targeted are medium caliber projectiles or arrow projectiles whose impact speed is

around 1300 to 1800m / s.

  To achieve this object, the shielding according to the invention combines different physical phenomena, namely, the erosion of the projectile, its ricochet and its rupture as well as the

  recovery of the degraded and broken projectile.

  To do this, the invention relates to a shield for protection against kinetic piercing projectiles, characterized in that it comprises: - an outer plate exposed to the impact of ceramic projectiles, - several inclined plates of high steel resistance and high incidence,

- a plate of ductile material.

  The role of the ceramic outer plate is to erode the

  tip of the projectile, in order to decrease its perforating power.

  The inclined plates of high resistance and high incidence steel have the role of favoring the ricochet and the destabilization of the projectile eroded by the ceramic. The function of the ductile material plate is to deform plastically under the impact of residual elements

of the projectile.

  According to a preferred embodiment, we associate with the

  ceramic outer plate with a honeycomb layer.

  This honeycomb layer has the function of improving the flexural strength of the ceramic and therefore its ballistic behavior by limiting the rise of cracks in the face.

  back of the ceramic towards the projectile.

  One embodiment consists in securing the ceramic outer plate to the honeycomb structure by

  a plate of metallic material.

  A shield preferably used comprises the following elements: an outer ceramic plate made of alumina or silicon carbide and with a thickness of 15 to 30 mm, - an aluminum honeycomb layer with a thickness of 8 to 12 mm , - a metal plate about 5mm thick on which the external ceramic plate is screwed, - very high density steel plates inclined at 75 degrees from normal, these parallelepipedic plates being parallel between separated by an air space of 30 to 50mm, - an air space of 30 to 50mm,

- a plate of ductile material.

  According to an advantageous embodiment, the rear plate of ductile material is made of steel and has a

  thickness between 15 and 20mm.

  According to an alternative embodiment, the rear plate of ductile material is made of aluminum and has a

  thickness between 35 and 45mm.

  The various components of the shield are assembled together by welding, screwing, by a system of

slides or hinges.

  The shielding according to the invention is integrated into a land vehicle by a gutter fixed on the vehicle and in

  which is fitted into the lower part of the shielding.

  The armor is integrated into a land vehicle by fixing lugs which are fixed both on the side parts of the vehicle and on the side parts of the armor. The invention is described in more detail, by way of example, with reference to the schematic figures which accompany it. Figure 1 shows a schematic sectional view

  transverse shielding according to the invention.

  Figure 2 shows a perspective view of a shield

  mounted on a wall of a vehicle.

  Figure 3 shows a schematic side view of the

assembly of figure 2.

  The shielding shown in FIG. 1 comprises, from outside to inside, the following elements: - an external ceramic plate 1 made of alumina with a relative density of between 98 and 99% and a thickness of 20mm, - a honeycomb layer 2 made of aluminum with a thickness of 10 mm, - a metal plate 3 5 mm thick on which the outer ceramic plate 1 is screwed, - plates 4 made of very high density steel inclined by degrees from normal, these parallelepipedic plates being parallel to each other and separated by an air space of 50mm, - an air space 5 of 50mm, - a plate 6 of ductile material made of aluminum

with a thickness of 36mm.

  Preferably, the inclined plates are made of THD steel with

500 Brinell.

  The length of these plates depends on the geometry of the vehicle.

  This shielding has excellent mass efficiency.

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  By mass efficiency is meant the ratio of the mass of steel necessary to stop a projectile to the mass of the armor. The firing results show a mass efficiency of 1.3 to 1.4 against sub-calibrated projectiles with a tungsten core. Figure 2 shows an integrated armor on a vehicle

  terrestrial by fixing lugs 7 and a gutter 8.

  The gutter 8 is shown in Figure 3.

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Claims (7)

  1- Shield for protection against kinetic projectiles, characterized in that it comprises: - an external ceramic plate (l) exposed to the impact of the projectiles, - several steel plates (4) inclined at a high incidence,   - a plate (6) of ductile material.   2- Shield according to claim 1, characterized in that one associates with the outer ceramic plate (1) a layer of honeycomb (2).   3- Shield according to claim 2, characterized in that the assembly consisting of the outer ceramic plate (1) and the honeycomb layer (2) is   secured by a plate of metallic material (3).   4- Armor according to claim 3, characterized in that it comprises the following elements: - an outer ceramic plate (1) made of alumina or silicon carbide and with a thickness of 15 to 30mm, - a layer of aluminum honeycomb (2) with a thickness of 8 to 12mm, a metal plate (3) about 5mm thick on which is screwed the outer ceramic plate - plates (4) made of very high density inclined from 65 to 75 degrees from normal, these parallelepipedic plates being parallel to each other and separated by an air space of 30 to 50mm, - an air space (5) of 30 to 50 mm ,   - a plate (6) of ductile material.   - Shielding according to claim 4, characterized in that the rear plate (6) of ductile material is made of steel and has a thickness of between 15 and mm. 6- Shielding according to claim 4, characterized in that the rear plate (6) of ductile material is made of aluminum and has a thickness of between 35 and 45mm.   7 - Armor according to claim 3, characterized in that it comprises the following elements: - an outer ceramic plate (1) made of alumina with a relative density of between 98 and 99% and a thickness of 20mm, - a honeycomb layer (2) made of aluminum with a thickness of 10 mm, - a metal plate (3) 5 mm thick on which the external ceramic plate is screwed, - plates (4) made of very high density inclined, 70 degrees from normal, these parallelepipedic plates being parallel to each other and separated by an air space of 50mm, - an air space (5) of 50 mm, a plate (6 ) made of ductile material made of aluminum with a thickness of 36mm.   8- Armor according to any one of claims   above, characterized in that its various constituent elements are assembled together by welding, screwing, by a system of slides or hinges.   9- Shield according to any of the claims   previous, characterized in that it is integrated into a land vehicle by a gutter (8) fixed on the vehicle and in which is embedded the lower part of the shielding.   - Shield according to any of the claims   above, characterized in that it is integrated into a land vehicle by fixing lugs (7) which are fixed both on the lateral parts of the