EP2063214B1 - Ballistic protective device - Google Patents

Description

The present invention relates to a ballistic protection device. It applies for example for the protection of vehicles or people against ballistic type attacks.

Ballistic protection devices equip various types of structures, equipment or people. For example, light vehicles likely to move in hostile territory, reconnaissance mission for example, are equipped with a ballistic protection.

The primary purpose of these devices is to effectively protect against ballistic aggression, including piercing projectiles. For this purpose, they comprise in particular one or more layers of steels generally associated with ceramic layers, all these layers being fixed together by glue joints or by screwed studs. These assemblies thus form shield panels capable of withstanding piercing projectiles of greater or lesser size and very high kinetic energy. These panels have several disadvantages. A first disadvantage is their weight and low maneuverability. In particular the materials constituting these panels and their necessary thicknesses give the whole a significant weight coupled with a lack of flexibility of use.

A second disadvantage lies in the lack of adaptation of these devices to more or less complex shapes. The protective panels used can not fit all kinds of shapes. For practical reasons, the dimensions of the panels can not fall below a certain surface, which limits the possible shapes, in particular the rounded shapes are excluded.

Another drawback comes in particular angles, or edges, protruding that can present these forms composed of flat panels. In particular, these angles or salient edges are easily identifiable by radar systems.

A document WO 94/09336 A discloses a multifilament protection with ballistic resistance.

An object of the invention is in particular to overcome the aforementioned drawbacks. For this purpose, the subject of the invention is a device for protecting against ballistic projectiles according to the main claim, comprising at least three layers of synthetic fabrics forming the reinforcements of the same piece obtained by resin transfer molding.

In the first layer, the fabric is for example composed of woven fibers in two dimensions, the warp and weft forming between them an angle less than or equal to 90 °.

In a particular embodiment, the first layer, projectile oriented, is composed of aramid fiber fabric.

the middle layer is made of fabric having glass fibers crossed with carbon fibers.

The middle layer is woven in three dimensions, the glass fibers and the carbon fibers being woven in two dimensions, the fibers of the glasses being oriented in a first direction and the carbon fibers being oriented in a second direction.

The two directions can cross at an angle less than or equal to 90 °, for example between 30 ° and 60 °.

These woven reinforcements, superimposed two by two, are linked together to ensure cohesion in the third direction.

The third layer is for example composed of fabric reinforcements linked two by two by the weaving process in the third direction.

A set of two woven reinforcements connected in pairs comprises a first carbon fiber reinforcement bonded to the second aramid fiber.

The fabric of the third layer comprises for example a finer mesh than that of the other layers.

Each layer has a stack of tissue layers, the number of layers of tissue depending on the desired thickness.

In a particular embodiment, the thickness of the third layer is half the thickness of the middle layer.

Advantageously, the resin may be a phenolic resin.

The proportion of resin is for example 30% and the proportion of fabrics is 70%.

• les figures 1a et 1b, des exemples de panneau de protection balistique selon l'art antérieur ;
• la figure 2, un exemple d'assemblage de panneaux du type de la figure 1 pour former une structure protectrice ;
• la figure 3, un exemple de réalisation possible d'un dispositif de protection selon l'invention ;
• les figures 4a et 4b, une illustration du principe de réalisation d'un tissage à deux dimensions ;
• les figures 5a, 5b et 5c, une illustration des principes de réalisation d'un tissage à trois dimensions ;
• la figure 6, un exemple possible de tissage pour former une dernière couche d'un dispositif selon l'invention ;
• la figure 7, une illustration d'un procédé de réalisation d'un dispositif selon l'invention.

Other characteristics and advantages of the invention will become apparent with the aid of the following description made with reference to appended drawings which represent:

• the Figures 1a and 1b examples of ballistic protection panel according to the prior art;
• the figure 2 , an example of assembly of panels of the type of the figure 1 to form a protective structure;
• the figure 3 an exemplary possible embodiment of a protection device according to the invention;
• the Figures 4a and 4b an illustration of the principle of making a two-dimensional weave;
• the figures 5a , 5b and 5c , an illustration of the principles of realization of a weaving in three dimensions;
• the figure 6 a possible example of weaving to form a last layer of a device according to the invention;
• the figure 7 , an illustration of a method of producing a device according to the invention.

The Figures 1a and 1b show an example of a ballistic protection panel 1 according to the prior art. This panel comprises several layers 11, 12, 13 juxtaposed, fixed together by adhesive layers of adhesive 10 or threaded studs 14. The outer layer is for example of ceramic-type material while the central layer 12 is made of steel, the layer 13 of composite type material. Depending on the thickness, in particular of this central layer 12, the panel is more or less heavy. In all cases of application, its weight is an obstacle.

The layers 11, 12 may also during the impact of a ballistic projectile produce rear effects such as splinters. These effects are generally harmful or even dangerous for the environment, especially for people.

The figure 2 presents an assembly of panels 1 of the type of that of the figure 1 for an application of a material 21. The assembly made as close as possible to the shape of this material 21, but not optimally.

The two panels are interconnected at their slices forming a projecting angle 22 because of the adopted contour. This angle can facilitate the detection of the whole by radar systems, notably by increasing the equivalent radar area.

The figure 3 presents an exemplary possible embodiment of a protection device according to the invention. The device is represented by a partial sectional view. The part shown is flat but it can advantageously take all kinds of other forms. The panel of the figure 3 is formed of a monoblock composite material comprising three layers 31, 32, 33 integral formed in the same mold.

The first layer 31 is disposed on the side of the threat, in this case the arrival of a ballistic projectile 30. It is for example composed of aramid fibers embedded in resin. The fibers are previously dry woven according to a two-dimensional weave. The dry fabric forms the reinforcement of the layer 31, several layers of tissue being necessary to obtain the desired thickness of the layer 31 obtained by resin transfer molding, as will be described later.

The Figures 4a and 4b illustrate the principle of producing a two-dimensional weave, respectively by a sectional view and a top view. Classically, the meshes cross in two dimensions, that is to say in a plane, forming a regular reinforcement. The figure 4b shows an example where the threads of the weft and warp intersect perpendicularly. It is possible to provide a weave where the son intersect at an angle other than 90 °, for example at an angle between 30 ° and 60 °.

The first layer 31 has for example a thickness of the order of 1 to 1.5 millimeters. The number of reinforcements superimposed to obtain the desired thickness can be determined a priori.

This first layer caliber at least the penetration diameter, it decreases the depth of penetration. It also prevents the aforementioned rear effects.

The second layer 32 comprises glass fibers and carbon fibers fixed in the matrix. These fibers are previously woven dry, according to a weaving in three dimensions, for example. This dry fabric forms the reinforcement of the layer 32.

The figures 5a 5b and 5c illustrate the principle of making a weaving in three dimensions. This weave comprises a first fiber reinforcement 51 and 51 ' according to a planar weave, in two dimensions, of the type of Figures 4a and 4b . In the case of the second layer 32, this reinforcement is for example composed of glass fibers 51 in one direction and carbon fibers 51 'in the other direction. As for the weaving of the first layer, these two directions can be oriented at an angle less than or equal to 90 °, for example between 30 ° and 90 °.

To this first reinforcement is superimposed a second reinforcement identical to the first, positioned in mirror symmetry with respect to the first.

The cohesion of the two reinforcements in the third direction is done, either by sewing with threads 52, or by a glue film 53. This second layer has a preponderant role insofar as it breaks the projectile or blocks it, and dissipates the energy due to shock. The size of the meshes of the weaving is particularly adapted to the diameter of the projectiles. Regarding the thickness, it is also adapted to the type of projectile and in particular its penetrating power. A thickness of the order of 50 to 80 millimeters may be necessary. The necessary woven reinforcements are stacked in sufficient number to obtain the desired thickness.

The third layer 33 is for example composed of woven reinforcements linked in pairs in the weaving process, these reinforcements then being juxtaposed to obtain the desired thickness. A first reinforcement comprises a first ply, for example made of carbon fiber or fiberglass, bonded to a second ply by passing a weft or warp thread from the first ply into the second ply, for example aramid fiber in the case of this layer 33.

The figure 6 illustrates one type of possible link between the two reinforcements. A first reinforcement 61 is seen from above. Weft son or chain 62 of the other reinforcement, located below, intersect meshes of this first reinforcement 61 to fix between them the two reinforcements. The weaving of the reinforcements is for example made according to a fine mesh.

In particular, this third layer 33 cash the residual deformation of the second layer 32, dissipates the shock wave. It brings in particular the resistance with the continuity of the material, by dissipation of the mechanical stresses in all the back face.

The third layer 33 has for example a thickness of the order of half the thickness of the second layer 32.

The thicknesses of the layers are adapted to the desired level of protection.

Protective layers 34, 35 are for example fixed on each side of the assembly formed of the three layers 31, 32, 33. A conductive film or a suitable paint may be applied to these layers.

The figure 7 illustrates a known method of producing a composite material part obtained by resin transfer molding. According to the invention, the three layers 31, 32, 33 are molded with resin, in one piece, to form a single-piece composite material. More particularly, all the layers are wetted at the same time by the resin. They are not stuck together.

The set of three layers is formed of superimposed fabrics 71, 72, 73. Each layer is characterized by its type of fabric. The number of tissue layers of each layer 31, 32, 33 depends on the level or type of protection sought as indicated above. These layers are stacked at the bottom of a mold 70, shown in section, whose inner shape corresponds to the shape that is sought to give the protective device. A very large number of forms is thus possible.

The top of the mold is closed by a cover 74, in fact a semi-permeable plastic cover. Seals 75 arranged between the cover and the mold make it possible to seal and thus to close the mold.

In a first phase, the dry tissue collections 71, 72, 73 are therefore stacked at the bottom of the mold, then the latter is closed by the cover 74. Then, a vacuum pump 77 is activated. This is connected by a conduit 78 inside the mold. This conduit 78 opens at a location at the level of the tissue layers, substantially opposite that which opens the arrival 76 of resin. In the next phase, by operating the stopcock 79, liquid resin is sent to the inside of the mold by a suitable conduit 76 placed so that the resin penetrates all the layers. A gate located at the duct 78 of the vacuum pump stops the flow of the resin.

Advantageously, spot thicknesses of tissue may be made in some places to make reinforcements or to contain inserts.

The resin used may be epoxy resin or phenolic resin. This last type of resin has the particular advantage of being a very good thermal insulator, which improves the fire resistance.

In the overall balance of the mass of a device according to the invention, the proportion of resin, forming the matrix, can be for example of the order of 30% and the proportion of tissue can be of the order of 70% . Such a structure provides a very significant weight gain while ensuring a very good mechanical strength as demonstrated by the tests performed by the Applicant.

Claims (15)

1. A protection device against ballistic projectiles, characterized in that it comprises at least three layers (31, 32, 33) of synthetic fabrics forming the reinforcements of one and the same piece obtained by resin-transfer molding, the middle layer (32) comprising glass fibers crossed with carbon fibers woven in a three-dimensional reinforcement, the glass fibers (51) and the carbon fibers (51') being woven in a two-dimensional reinforcement, the glass fibers being oriented in a first direction and the carbon fibers being oriented in a second direction, the cohesion in the third direction being provided by a bond (52) between these reinforcements arranged in mirror-symmetrical pairs.
2. The device as claimed in claim 1, characterized in that the two directions cross at an angle of less than 90°.
3. The device as claimed in claim 2, characterized in that the two directions cross at an angle of between 30° and 60 °.
4. The device as claimed in any one of the preceding claims, characterized in that the second weft (52) consists of carbon fibers or glass fibers.
5. The device as claimed in any one of the preceding claims, characterized in that the bond (53) is the result of a gluing method.
6. The device as claimed in any one of the preceding claims, characterized in that, in the first layer (31), oriented towards the projectiles, the fabric consists of aramid fibers.
7. The device as claimed in any one of the preceding claims, characterized in that, in the first layer (31), oriented towards the projectiles, the fabric consists of fibers woven in two dimensions, in two directions forming between them an angle of less than or equal to 90°.
8. The device as claimed in claim 7, characterized in that the angle is between 30° and 60 °.
9. The device as claimed in any one of the preceding claims, characterized in that the third layer (33) consists of fabric reinforcements (61, 62) linked in pairs.
10. The device as claimed in claim 9, characterized in that a set of two reinforcements (61, 62) linked in pairs comprises a first reinforcement of carbon or glass fibers linked to a second reinforcement of aramid fibers.
11. The device as claimed in any one of the preceding claims, characterized in that the fabric of the third layer (33) comprises a finer mesh than that of the other layers (31, 32).
12. The device as claimed in any one of the preceding claims, characterized in that each layer (31, 32, 33) comprises a stack of fabric layers (71, 72, 73), the number of fabric layers depending on the desired thickness and the projectile stopping power.
13. The device as claimed in any one of the preceding claims, characterized in that the thickness of the third layer (33) is half the thickness of the middle layer (32).
14. The device as claimed in any one of the preceding claims, characterized in that the resin is a phenolic resin.
15. The device as claimed in any one of the preceding claims, characterized in that the proportion of resin is 30% and the proportion of fabrics is 70%.

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