Optronic equipment containing ballistic armor

Abstract

The present invention relates to optronic equipment (40) containing ballistic armor (10) comprising a three-dimensional reticular structure (20), which can in particular be regular and / or auxetic, and to a manufacturing process comprising a step of additively manufacturing at least the three-dimensional reticular structure (20).

Description

Technical Field

[0001] This disclosure relates to armor and in particular ballistic armor intended to protect optronic equipment from the effects of impacts from high-speed projectiles or debris, as described for example in WO2018193023 A. Previous technique

[0002] Typically, ballistic armor, especially that intended to protect optronic equipment such as turret-mounted sights or other equipment, consists of massive, relatively thick plates designed to fragment and slow projectiles. While robust and relatively inexpensive, this conventional armor is heavy and rigid, which can lead to several disadvantages. For example, on a turret-mounted panoramic sight, the weight of the ballistic armor may necessitate the use of larger, more powerful actuators to rotate the turret on each axis, while its rigidity may require additional damping measures, such as the addition of elastomer or polymer foams, to limit the transmission of impact stresses and vibrations to sensitive equipment.

[0003] In other applications, such as personal protective equipment like helmets and bulletproof vests, or gas turbine engine casings, the weight and rigidity of massive armor can also cause other disadvantages, such as, for example, hindering the movement of infantrymen wearing this protective equipment.

[0004] Furthermore, as illustrated on the figure 1 The deformation of a massive armor 100 following the impact of debris or a projectile 110 can also lead to cracks 120 weakening the massive armor 100 against subsequent impacts, or even spalling on the rear face of the armor 100, generating secondary debris 130 which can themselves damage the equipment and / or people that the armor 100 is supposed to protect. Description of the invention

[0005] According to claim 1, a first aspect of the present invention relates to optronic equipment incorporating ballistic armor having a three-dimensional lattice structure to form an architected material capable of better absorbing impacts from projectiles or debris by preventing crack propagation and spalling, and with reduced weight. This three-dimensional lattice structure may, in particular, comprise a regularly repeated unit cell to form a regular structure, but could alternatively be a stochastic structure with strands and / or thin walls entangled in a substantially random manner.

[0006] To better absorb impacts, the three-dimensional lattice structure can be auxetic, meaning it has a negative Poisson's ratio. Thus, the compression of the three-dimensional lattice structure in the direction of a ballistic impact would also cause its local contraction perpendicular to the direction of the impact, thereby distributing the impact energy by tension to the surrounding regions.

[0007] Besides the three-dimensional lattice structure, ballistic armor can also include one or more panels. Such a panel can, for example, be placed on an external surface of the ballistic armor to fragment projectiles or debris before they penetrate the three-dimensional lattice structure. It is also possible for the ballistic armor to consist of two opposing panels, between which the three-dimensional lattice structure is sandwiched, forming a lightweight yet rigid sandwich structure. However, it is also possible, in addition to or as an alternative to panels placed on one or more external surfaces of the ballistic armor, to place at least one panel within the three-dimensional lattice structure itself, for example, sandwiched between consecutive layers of the three-dimensional lattice structure.

[0008] At least one property of the three-dimensional reticular structure, such as the shape and / or size of a single cell and / or its density, can evolve along at least one axis. This evolution can be staged, forming distinct blocks or layers in the three-dimensional reticular structure, but it can also be gradual.

[0009] An empty volume inside the three-dimensional lattice structure can be at least partially filled with a different material, in order to combine its properties with those of the three-dimensional lattice structure.

[0010] According to claim 8, a second aspect of the present invention relates to a method for producing ballistic armor for optronic equipment according to the first aspect, comprising an additive manufacturing step of at least the three-dimensional lattice structure, for example by laser powder bed fusion, laser powder bed sintering, molten filament deposition, binder jetting, stereolithography, or photocurable resin jetting, so as to easily obtain a complex lattice structure. Brief description of the drawings

[0011] The description refers to the attached drawings on which: [ Fig. 1 ] There figure 1 schematically illustrates the effects of a ballistic impact on massive armor. Fig. 2 ] There figure 2 schematically illustrates a first method of implementing ballistic armor incorporating a three-dimensional lattice structure. Fig. 3 ] There figure 3 illustrates the reaction of the three-dimensional lattice structure of the first embodiment to a compressive force. Fig. 4 ] There figure 4 schematically illustrates a second embodiment. Fig. 5 ] There figure 5 schematically illustrates an application of ballistic armor according to the second embodiment for the protection of optronic equipment. Fig. 6 ] There figure 6 schematically illustrates a third embodiment. Fig. 7 ] There figure 7 schematically illustrates a fourth embodiment. Fig. 8 ] There figure 8 schematically illustrates a fifth embodiment. Fig. 9 ] There figure 9 schematically illustrates a process for producing ballistic armor according to any one of the preceding embodiments. Description of the implementation methods

[0012] The invention will be well understood and its advantages will become more apparent upon reading the detailed description that follows, of embodiments represented by way of non-limiting examples.

[0013] According to a first embodiment, as illustrated on the figures 2 et 3 Ballistic armor 10 may include a three-dimensional lattice structure 20, designed to form an architected material, that is, with a morphology and / or topology that gives it specific enhanced properties. In particular, the morphology and / or topology of this three-dimensional lattice structure 20 may be adapted to better absorb the energy of impacts from debris and / or projectiles, and / or limit the deformation of its rear face, the propagation of cracks, and / or spalling in the event of an impact.

[0014] For example, the three-dimensional lattice structure 20 can be configured to make it auxetic, as illustrated in the figure 3 This demonstrates how a compressive force F, such as that caused by the impact of a high-speed projectile or debris, can also cause a contraction of this three-dimensional lattice structure 20 in a direction perpendicular to that of the compression. This lateral contraction can thus distribute the impact force laterally over a larger area and more efficiently, while limiting the deformation of the rear face of the ballistic armor 10.

[0015] Furthermore, as illustrated on the figures 2 et 3 The three-dimensional reticular structure 20 can be a regular structure, formed by the regular repetition of a unit cell 21 composed of an arrangement of strands 22 and / or thin walls in space. However, it is also possible that this three-dimensional reticular structure 20 is a stochastic structure, with a random arrangement of strands and / or walls.

[0016] Although in the embodiment illustrated on the figures 2 et 3 The ballistic armor 10 is formed solely by the three-dimensional lattice structure 20; it is also possible to combine such a three-dimensional lattice structure with other elements in order to combine their properties. Thus, in a second embodiment, illustrated in the figures 4 et 5 The ballistic armor 10 may include, apart from the three-dimensional lattice structure 20, a solid panel 30 disposed on an external face of the ballistic armor 10 in order to fragment projectiles and / or debris impacting at high speed, while distributing the force transmitted by the impact over a larger surface of the three-dimensional lattice structure 20. This panel 30 may be formed in one piece with the latter, or made integral to it for example by gluing, welding or mechanical connection by friction or complementary shape.

[0017] There figure 5 This also illustrates an application of this ballistic armor 10 for the protection of optronic equipment, and more specifically, optronic equipment 40 in the form of a turret-mounted sight. This optronic equipment 40 can therefore include a set of sensors 50 mounted on a turret 60 which may have one or more axes of rotation, such as a vertical Z-axis and a horizontal X-axis. The turret 60 can be motorized with actuators (not shown) for each axis of rotation Z, X.

[0018] Both the sensor assembly 50 and the turret actuators 60 can be vulnerable to impacts, and even vibrations. To protect them, the optronic equipment 40 can therefore include a housing 70 in one or more parts, each incorporating such ballistic armor 10.

[0019] Although in the embodiment illustrated on the figures 4 et 5 While a solid panel may only be incorporated on the outer face of the ballistic armor, it is also possible to incorporate another on the inner face. Thus, in a third embodiment, illustrated in the figure 6 The ballistic armor 10 can comprise, in addition to the three-dimensional lattice structure 20, solid panels 30 and 30' arranged respectively on an outer and an inner face of the ballistic armor 10, with the three-dimensional lattice structure 20 sandwiched between the two, so as to form a sandwich structure. Each of these panels 30 can be formed as a single piece with the three-dimensional lattice structure 20, or joined to it, for example, by gluing, welding, or mechanical bonding by friction or complementary shape. It is thus possible to produce ballistic armor 10 that is rigid in bending but nevertheless lightweight and offers good impact energy absorption properties.

[0020] It is also possible to incorporate one or more solid panels within the three-dimensional lattice structure, between the inner and outer faces of the ballistic armor. Thus, in a fourth embodiment, illustrated in the figure 7 The ballistic armor 10 may comprise a first solid panel 30 disposed on an external face of the ballistic armor 10 and a second panel 30' sandwiched between two layers 20a, 20b of the three-dimensional lattice structure 20. Furthermore, these layers 20a, 20b may have different properties, and in particular different densities, as illustrated in the figure 8 . For this purpose, they can notably be formed by regular repetition of different respective unit cells 21a, 21b.

[0021] Although in the embodiment illustrated on the figure 7 The three-dimensional lattice structure presents two distinct layers, with a stepped evolution of the properties of the three-dimensional lattice structure along the axis; however, it is also conceivable to have a gradual evolution of the properties of the three-dimensional lattice structure. Thus, in ballistic armor 10, according to a fifth embodiment, illustrated on the figure 9 The properties of the three-dimensional lattice structure 20, and in particular its density, can evolve gradually without abrupt changes. Although in the illustrated examples this evolution is in the direction of thickness, it is also conceivable to have gradual or abrupt changes in the properties of the three-dimensional lattice structure, to obtain, for example, different responses to impacts on different areas of the outer surface of the ballistic armor.

[0022] Furthermore, as also illustrated on the figure 8 , an empty volume inside the three-dimensional reticular structure 20 can be at least partially filled by a different material 22, such as a foam, so as to form, with the three-dimensional reticular structure 20, a composite material combining properties of the three-dimensional reticular structure 20 and of the material 22. Although this at least partial filling is illustrated only in this figure, it is also applicable to the previous embodiments.

[0023] Additive manufacturing processes offer increased flexibility for the fabrication of three-dimensional lattice structures. Consequently, as illustrated in the figure 9 A method for producing ballistic armor 10 according to any of the aforementioned embodiments may include an additive manufacturing step of at least the three-dimensional lattice structure 20, for example from a digital model thereof. This digital model may be decomposed into a series of successive slices, and the additive manufacturing of at least the three-dimensional lattice structure may proceed by the selective, computer-controlled deposition and / or consolidation of successive layers of material corresponding to the slices of the digital model.

[0024] Thus, in an additive manufacturing step by laser powder bed sintering, as illustrated in the figure 9 Layers of powder 90, normally metallic, are successively applied, and between the application of successive layers, a laser beam 91, directed by a computer 92 based on a digital model, decomposed into successive slices, of at least the three-dimensional lattice structure 20, will selectively melt the powder according to the shape of the corresponding slice of the digital model, so as to selectively consolidate the powder material during its cooling and re-solidification and thus produce at least this three-dimensional lattice structure 20 according to the digital model. As illustrated in the figure 9 Other elements of the ballistic armor 10, for example one or more solid panels 30, 30', can be manufactured by additive manufacturing in conjunction with the three-dimensional lattice structure 20, so as to form a single unit. However, subsequent finishing and / or assembly steps are also possible to obtain the ballistic armor 10 in its final form. Furthermore, although the illustrated process is a powder bed fusion additive manufacturing process, other types of additive manufacturing processes, such as powder bed fusion, fused filament deposition, binder jetting, stereolithography, or photocurable resin jetting, are also feasible in a similar manner.

[0025] Although the present invention has been described with reference to specific embodiments, it is evident that various modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. Furthermore, individual features of the various embodiments mentioned can be combined in additional embodiments. For example, the method illustrated in the figure 9 is applicable to the manufacture of ballistic armor according to each of the embodiments of figures 2 à 8 Each of these ballistic armors is likely to be used in the application illustrated by the figure 5 Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

Claims

1. An optronic device (40) incorporating a ballistic armour (10) characterised in that said ballistic armour comprises a three-dimensional reticular structure (20).

2. The optronic device (40) according to claim 1, wherein the three-dimensional reticular structure (20) of the ballistic armour (10) comprises a regularly repeated unit cell (21).

3. The optronic device (40) according to any one of claims 1 or 2, wherein the three-dimensional reticular structure (20) of the ballistic armour (10) is auxetic.

4. The optronic device (40) according to any one of claims 1 to 3, wherein the ballistic armour (10) also comprises one or more panels (30, 30').

5. The optronic device (40) according to claim 4, wherein the ballistic armour (10) comprises two opposite panels (30, 30'), between which the three-dimensional reticular structure is inserted, so as to form a sandwich structure.

6. The optronic device (40) according to any one of claims 1 to 5, wherein at least one property of the three-dimensional reticular structure (20) of the ballistic armour (10) evolves along at least one axis.

7. The optronic device (40) according to any one of claims 1 to 6, wherein a hollow volume inside the three-dimensional reticular structure (20) of the ballistic armour (10) is filled by a different material (22).

8. A method for producing the optronic device (40) according to any one of claims 1 to 7, comprising a step of additive manufacturing of at least the three-dimensional reticular structure (20) of the ballistic armour (10).

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