EP3671101A1 - Projectile-resistant composite comprising ceramic elements - Google Patents

Abstract

The invention relates to a bullet-resistant composite (11) made of ceramic elements (1). According to the invention, the task of finding a simple way of building a bullet-resistant composite (11) from a layer of ceramic elements (1) is achieved by a ceramic element (1) which has the shape of a differential body which is distinguished by the difference between two cylinders (2 ) is formed, whose axes of symmetry (10) run parallel and are arranged at a distance of half a diameter (d), the outer surface consisting of a convex first outer surface (3) and a concave second outer surface (4) and a top surface (5th ) and a base surface (6) are two mutually parallel, spherically curved surfaces, so that a height (H) of the ceramic element (1) is greater than a height (h) of the cylinder (2).

Description

The invention relates to a bullet-resistant composite made of ceramic elements.

Because of their great hardness and low weight, ceramics are often used in modern anti-bullet protection devices and develop particularly in composite systems in which they e.g. used in conjunction with fiber fabrics and / or metals and / or plastics, an excellent protective effect. The properties of the bullet-proof protective device can be specifically influenced by the geometric shape and the selection of material properties of the ceramics. Area-wide bullet-proof protective devices are often composed of a large number of smaller ceramic elements or ceramic plates. This makes them e.g. adaptable to curved surfaces much better and more flexibly than would be possible by using large-area ceramic elements that are flat or that are already adapted to a curvature of surfaces. In addition, individual elements of protective devices constructed in this way can be replaced much more easily and cost-effectively in the event of damage.

Ceramic elements, such as those used to build bullet-resistant composites, are already known from the prior art. A typical form is e.g. cylindrical ceramic elements that are aligned with their axis perpendicular to a surface to be protected and thus in the direction of an expected attack. The protective effect of the bullet-resistant composite is essentially determined by the height of the cylinders.

In the WO 00/47944 A1 discloses a bullet-resistant composite, which is composed of cylindrical ceramic elements of the same diameter and flat end faces. The cylinders are arranged orthogonally on a flat carrier material in a hexagonally sealed packing. The cylinders can have the form of flat disks in light protective devices or have a significantly greater height in heavy protective devices. In the spaces between the cylinders remaining in the hexagonally sealed packing, cylindrical filling elements with a smaller diameter can be inserted, by means of which the size of the spaces is reduced.

The WO 98/15796 A1 shows cylindrical ceramic elements with the same diameter, which form a bullet-resistant composite. The cylinders are arranged orthogonally on a flat carrier material in a hexagonally sealed packing. At least one of the two end faces of the cylindrical ceramic elements is convexly curved.

In the CN 204 329 778 U are described cylindrical ceramic elements of the same diameter, which have hemispherical end faces and are arranged in a hexagonally sealed packing orthogonal to a flat carrier material.

With those from the RU 2 462 682 C2 known cylindrical ceramic elements, the end faces have convex curvatures. The ceramic elements are arranged orthogonally with the axis on a flat support. The transition between the curved end faces and the outer surface can be provided with concave or convex radii or with chamfers. The aforementioned RU 2 462 682 C2 also discloses ceramic elements with a hexagonal cross section, which also have curved end faces. The hexagonal cross-section allows gaps in the hexagonally sealed packing to be reduced to a minimum.

The cylindrical ceramic elements disclosed in the abovementioned documents have in common that they are always arranged orthogonally to a flat carrier and thus in one plane. There is no provision for the ceramic elements to be arranged on a curved support. With the orthogonal arrangement of the cylinders to the carrier material described, it can be assumed that gaps that occur in the hexagonally tight packing between the cylinders widen even further with the same arrangement of the cylinders on convexly curved surfaces. The gaps between the elements could possibly be covered if the ceramic elements are used in at least a second layer. However, the use of a second layer also increases the manufacturing effort. It is not possible to use the orthogonal arrangement on concavely curved surfaces. This problem would also apply to the ceramic elements with a hexagonal cross section from the aforementioned RU 2 462 682 C2 hold true.

The WO 2008/055468 A1 discloses chain-like flexibly connected elements that can be made from hard materials, such as ceramic, and with different cross-sections, from circular to polygonal. The ceramic elements are arranged with their axes parallel to each other. Various shapes are also possible for the formation of the end faces. When using the ceramic elements in a bullet-resistant composite, adjacent chains are offset from one another in a tight packing and with the axes either orthogonal, angled or arranged parallel to a carrier. In the case of an arrangement in which the axes are angled or oriented parallel to the support, it is also conceivable to lay them on curved surfaces. Due to the then lower height of the ceramic elements in the direction of attack, a reduced protective effect can be assumed compared to the orthogonal laying. With the angled arrangement it can also be assumed that the composite has different protective effects depending on the angle of the attack direction. With the parallel arrangement, the lower element height could be compensated for by using a second layer, which would be associated with a higher production outlay.

The use of several layers of flat elements is in the DE 10 2017 102 975 A1 disclosed. The elements are spheres, which can be made of ceramic materials, among other things, and are stacked in layers or arranged irregularly in several layers. The balls are permanently connected to each other in a tight package. Plate-shaped protective elements are made from the balls, which are put together in textile carriers to provide body protection. Thanks to the textile carrier, the protective elements can adapt well to the shape of the body. However, gaps remain between the protective elements, which prevent the body protection from being closed completely.

In the WO 2014/082621 A1 is shown an anti-bullet compound, which consists of a combination of flat polyhedral basic elements with a square base and filling elements. Basic elements and filling elements consist of ceramic material. The basic element has several inclined surfaces, so that pyramidal depressions result on both sides of a layer of basic elements, which can be filled with the filling elements. The form-fitting filling elements cover those between the basic elements remaining gaps as far as possible. The bullet-resistant composite is also suitable for curved surfaces, but has the disadvantage that several different types of elements are required for its construction.

The DE 10 2006 050 130 A1 shows a bullet-resistant composite consisting of two layers of ceramic elements. The ceramic elements are conical. In the first layer, the ceramic elements are attached to one another with adjoining base areas. With the second layer, the conical gaps in the first layer are filled with ceramic elements inserted in a mirror-inverted manner. If only convex curvatures are involved, the composite is also suitable for curved surfaces.

A number of other documents can be found in the prior art, in which possibilities for avoiding gaps between the individual elements of an anti-bulletproof compound are disclosed.

The US 5,996,115 A describes a light bullet-resistant composite, which is composed of rectangular plate-shaped ceramic elements. The side surfaces of the elements are angled in relation to the base and top surfaces, so that adjacent side surfaces of two neighboring elements are parallel at an angle. Due to the angled side surfaces, the adjacent elements overlap so that there are no gaps between the elements orthogonal to the base and top surfaces and thus in the direction of attack. For a better adaptation to curved surfaces, the elements can be curved in one spatial direction.

An Indian US 5,771,489 A. The plate-shaped element shown made of a ceramic material has an essentially rectangular base area. At least one of two parallel edges of the element is designed as a hinge-like connection, one edge forming the positive shape and the other edge forming the negative shape of the hinge. Opposing edges of two adjacent elements can be pushed into each other and connected in a form-fitting manner. The hinge enables an articulated and gapless connection of the elements, which allows the bullet-resistant composite to be adapted to surfaces curved in one spatial direction. The edges running in the other spatial direction can be stepped, so that neighboring elements overlap without gaps. Due to the overlap, a limited adaptation to slight curvatures in the second spatial direction is possible.

In the WO 2012/026925 A1 discloses a plate-shaped square ceramic element, the four edges of which are always stepped and additionally provided with facets, chamfers or radii. The gradation of the edges of the elements laid in one layer overlaps the edges. The facets, chamfers or radii make it easier to lay the elements on curved surfaces while at the same time covering gaps between the elements. The elements can be curved in one spatial direction for laying on curved surfaces.

The latter three documents have in common that the plate-shaped elements due to the low height of the elements for bullet-resistant composites with a slight protective effect, such as are designed for protective vests. Such elements cannot be used sensibly for producing bullet-resistant composites with a greater protective effect and with surfaces which have a convex and concave curvature in two spatial directions.

An Indian WO 00/33013 A2 disclosed disc-shaped ceramic element with a circular base and top surface is laid out in a hexagonal arrangement overlapping in one layer. The ceramic elements can have the shape of a flat cylindrical disk, a disk angled in a spatial direction, a meniscus-shaped disk, a biconvex lens or combinations thereof. The ceramic elements can have recesses on the cover surfaces which are precisely adapted to the diameter of the overlapping ceramic element. Some of the shapes of these elements are suitable for seamlessly covering curved surfaces in two spatial directions. A higher protective effect cannot be achieved with a layer of these relatively flat ceramic elements.

The object of the invention is to find a simple way to build a bullet-resistant composite from a layer of ceramic elements, the is also completely closed on curved surfaces in the direction of attack and has a high protective effect.

According to the invention, the object is achieved by a bullet-resistant composite consisting of ceramic elements, each ceramic element consisting of a cylinder having a diameter and a height with an axis of symmetry, an outer surface, a top surface, a base surface and a recess, in that the ceramic element has the Has the shape of a differential body, formed by a difference between two cylinders, the axes of symmetry of which run parallel and have a distance of half the diameter and the outer surface consists of a convex first outer surface and a concave second outer surface, and the top surface and the base surface are two mutually parallel, are spherically curved surfaces, so that a height of the ceramic element is greater than the height of the cylinder.

Fig. 1 -

einen prinzipiellen Aufbau eines Keramikelements in einer dreidimensionalen Ansicht,

Fig. 2 -

eine Ausführung des Keramikelements in einer geschnittenen Seitenansicht,

Fig. 3 -

eine Ausführung des Keramikelements in einer Draufsicht,

Fig. 4 -

einen prinzipiellen Aufbau eines beschusshemmenden Verbunds aus einer Lage der Keramikelemente in einer dreidimensionalen Ansicht,

Fig. 5 -

eine prinzipielle Anordnung der Keramikelemente in einem beschusshemmenden Verbund auf einer konkav gekrümmten Oberfläche und

Fig. 6 -

eine prinzipielle Anordnung der Keramikelemente in einem beschusshemmenden Verbund auf einer konvex gekrümmten Oberfläche.

The invention will be explained in more detail below on the basis of exemplary embodiments. In the accompanying drawings:

Fig. 1 -

a basic structure of a ceramic element in a three-dimensional view,

Fig. 2 -

an embodiment of the ceramic element in a sectional side view,

Fig. 3 -

one embodiment of the ceramic element in a top view,

Fig. 4 -

a basic structure of a bullet-resistant composite from a position of the ceramic elements in a three-dimensional view,

Fig. 5 -

a basic arrangement of the ceramic elements in a bulletproof compound on a concave curved surface and

Fig. 6 -

a basic arrangement of the ceramic elements in a bulletproof compound on a convex curved surface.

In the case of a bullet-resistant composite 11 made of ceramic elements 1, the ceramic elements 1 are in principle as in FIG Fig. 1 shown built. Each ceramic element 1 is a cylinder 2 with an axis of symmetry 10, which has a diameter d and a Height h. The ceramic element 1 has the shape of a differential body, which is formed by a difference between two cylinders 2, the axes of symmetry 10 of which are arranged parallel and at a distance of half a diameter d from one another. The ceramic element 1 has a first lateral surface 3 and a second lateral surface 4. A top surface 5 and a base surface 6 of the ceramic element 1 are two mutually parallel, spherically curved surfaces. A height H of the ceramic element 1 is greater than the height h of the cylinder 2.

In 2 and 3 a first embodiment of the ceramic element 1 is shown in a sectional side view and in a top view, the shape of the cylinder 2 being indicated by a broken dash line. The diameter d of the cylinder 2 on the first lateral surface 3 is 20 mm and the height h is half the diameter d.

In Fig. 2 the spherical top surface 5 and the spherical base surface 6 are shown with a broken line of dots. They have a radius r that corresponds to half the diameter d. As a result, the spherical cover surface 5 and the spherical base surface 6 merge tangentially into the first lateral surface 3. Due to the curvature of the spherical cover surface 5, the height H of the ceramic element 1 is greater by the radius r than the height h of the cylinder 2.

In Fig. 3 the cross section of the ceramic element 1 can be seen, which results from the difference between the cross sections of two cylinders 2 of the same size, which penetrate at a distance of half a diameter d and with parallel axes of symmetry 10. The resulting differential body then has the outwardly curved first lateral surface 3 and the inwardly curved second lateral surface 4. As can be seen from the broken dashed lines, the second lateral surface 4 forms a first edge 7 with the first lateral surface 3, the edge angle of which is significantly smaller than 90 °. As in Fig. 2 to recognize, the base surface 6 tapering tangentially into the first lateral surface 3 forms a very sharp second edge 8. Such edges 7 or 8 can only be produced with a large amount of production effort and would be mechanically very unstable.

In a second embodiment of the ceramic element 1, the first edge 7 and the second edge 8 are provided with a rounding 9. The rounding 9 points to the first Edge 7 has a radius of 1/20 of the diameter d and on the second edge 8 a radius of 1/40 of the diameter d. As in 2 and 3 shown, the fillets 9 each have a tangential transition to the respectively adjacent surfaces. The roundings 9 significantly increase the strength of the first edge 7 and the second edge 8 and thereby increase the mechanical stability of the entire ceramic element 1.

Of course, it is also possible to vary the radius of the rounding 9 to a certain extent, deviating from the dimensions mentioned above. Taking into account the mechanical stability of the edges 7 and 8, the radius always has a maximum value and a minimum value at which (as later on) Fig. 4 described), a sufficient overlap between adjacent ceramic elements 1 can still be produced even when laying on curved surfaces 12 and an articulated movement between the adjacent ceramic elements 1 is not restricted.

The ceramic element 1 is made of oxide-ceramic or non-oxide-ceramic materials such as Al ₂ O ₃ , ZrO ₂ , SiC, BN. Due to their great hardness and low density, these materials are particularly well suited for the manufacture of bullet-resistant composites, which have a significantly reduced weight compared to steel armouring. The shaping is preferably carried out by means of a dry pressing process with which the ceramic elements 1 can be inexpensively manufactured in large numbers.

In the Fig. 4 a section of the bullet-resistant composite 11 is shown in one possible embodiment. The bullet-resistant composite 11 is composed of a plurality of ceramic elements 1, which are arranged in one layer on a flat surface 12 extending in the xy direction. The ceramic elements 1 are placed with the first lateral surface 3 on the surface 12, the second lateral surface 4 being oriented in the x direction.

When building the bullet-resistant composite 11 is corresponding Fig. 4 started in the right half of the picture with a first row of ceramic elements 1 arranged axially one behind the other. In the axial alignment, the ceramic elements 1 on the top surfaces 5 and the base surfaces 6 are mutually aligned. Because the top surfaces 5 and the base surfaces 6 have the same radius r, the ceramic elements 1 bear against one another in a positive manner in the y direction.

Each further row of ceramic elements 1 lying axially on one another, which is applied to the surface 12, is placed with the second lateral surfaces 4 on the first lateral surfaces 3 of an already installed row. The ceramic elements 1 rotate about the axes of symmetry 10, which leads to an optimal alignment of the ceramic elements 1 to the surface 12. Characterized in that the curvatures of the first lateral surfaces 3 and the second lateral surfaces 4 have the same radius r, the ceramic elements 1 bear against one another in the x-direction in a form-fitting manner.

Due to the positive locking in the x and y directions, the ceramic elements 1 always overlap with one another orthogonally to a direction of attack 13, so that no open gaps remain between the ceramic elements 1. For the most part, the z direction is assumed to be the attack direction 13, essentially perpendicular to the bullet-resistant composite 11. With one layer of the ceramic elements 1, a closed bullet-resistant composite 11 can be produced with a thickness that almost corresponds to the diameter d.

The curvatures of the first lateral surfaces 3, the second lateral surfaces 4 and the spherical cover and base surfaces 5 and 6, as well as the roundings 9 on the second edges 8 allow an articulated movement between the ceramic elements 1, through which the bullet-resistant composite 11 also on curved surfaces 12 is customizable.

As in 5 and 6 shown, the surface 12 can be both convex and concave curved. In the case of a surface 12 which is curved only in one spatial direction, that is to say either in the x or y direction, the form fit between the ceramic elements 1 can be fully maintained if the axial alignment of the ceramic elements 1 is exactly parallel or orthogonal to the direction of the curvature. In Fig. 5 the bullet-resistant composite 11 is laid on a surface 12 which is concavely curved in the x direction. The ceramic elements 1 are arranged with the axis of symmetry 10 parallel to the y direction. In Fig. 6 is the bullet-resistant composite 11 on a convexly curved in the y-direction Surface 12 laid. The ceramic elements 1 are arranged with the axis of symmetry 10 orthogonal to the x direction.

The articulated movement between the ceramic elements 1 also allows the bullet-resistant composite 11 to be laid on surfaces 12 which are concave or convex in two spatial directions. In the case of such a lay or in a lay in which the axes of symmetry 10 are not oriented parallel or orthogonal to the direction of the curvature , there may be shifts between the rows of axially adjacent ceramic elements 1 in the direction of the axes of symmetry 10.

The displacements in the y direction are exemplary in Fig. 4 shown on the bullet-resistant composite 11 arranged on the flat surface 12. In the right half of the picture there is no shift between the rows of ceramic elements 1. The shift increases in the direction of the left half of the picture to a maximum.

On surfaces 12 which are curved at least in the y direction, these displacements mean that a complete positive fit can no longer be achieved between the first lateral surface 3 and the second lateral surface 4. The complete interlocking is also not absolutely necessary, since the existing overlaps between the ceramic elements 1 mean that there are no open spaces even when the interlocking is incomplete, so that the bullet-resistant composite 11 is always closed.

In another embodiment of the bullet-resistant composite 11, not shown in the figures, the radius r of the spherical cover surface 5 and the spherical base surface 6 is made larger, regardless of the diameter d. The radius r can be, for example, in the range between 50 and 200 mm. The ceramic elements 1 are produced with a larger diameter d, for example in the range from 50 to 100 mm, and with a relatively lower height H, for example in the range from 20 to 50 mm. Such ceramic elements 1 are better designed for bullet-resistant composites 11 with a higher protective effect, but have restrictions when laying on strongly curved surfaces 12.

In a further embodiment, not shown in the figures, the radius r of the base area 6 and the second lateral area 4 is slightly larger than the radius r of the cover area 5 and the first lateral area 3. Here, slightly means that the radii r are in the range from to can be larger to 1/20 of half the diameter d.

In further versions of the bullet-resistant composite 11, the ceramic elements 1 can also have any other size. It is essential that the ceramic element 1 is always a differential body made of two cylinders 2 of the same size with parallel axes of symmetry 10 and the top surface 5 and the base surface 6 are always spherically curved surfaces which have the same or almost the same radius r. The dimensioning of the diameter d and the height H can be adapted to the desired properties of the bullet-resistant composite 11 and in accordance with the properties of the surface 12.

Reference symbol list

1

Ceramic element

2nd

cylinder

3rd

first lateral surface

4th

second lateral surface

5

Top surface

6

Floor space

7

first edge

8th

second edge

9

Rounding

10th

Axis of symmetry

11

bulletproof composite

12

surface

13

Attack direction

d

Diameter of the cylinder 2

H

Height of the cylinder 2

H

Height of the ceramic element 1

r

radius

Claims (10)

Bullet-resistant composite (11), consisting of ceramic elements (1), each ceramic element (1) consisting of a cylinder (2) with a diameter (d) and a height (h) with an axis of symmetry (10), a lateral surface, a top surface ( 5), a base (6) and a recess, characterized in that - The ceramic element (1) has the shape of a differential body, formed by a difference between two cylinders (2), the axes of symmetry (10) of which run parallel and have a distance of half the diameter (d) and the outer surface consists of a convex first outer surface ( 3) and a concave second lateral surface (4), and - The top surface (5) and the base surface (6) are two mutually parallel, spherically curved surfaces, so that a height (H) of the ceramic element (1) is greater than the height (h) of the cylinder (2). Bullet-resistant composite (11), consisting of ceramic elements (1), according to claim 1, characterized in that the first lateral surface (3) and the second lateral surface (4) together form a closed surface. Bullet-resistant composite (11) consisting of ceramic elements (1) according to claim 1 or 2, characterized in that the height (h) of the cylinder (2) has half the diameter (d). Bullet-resistant composite (11), consisting of ceramic elements (1), according to one of claims 1 to 3, characterized in that the height (H) of the ceramic element (1) by half the diameter (d) greater than the height (h) of the Cylinder (2) is. Bullet-resistant composite (11) consisting of ceramic elements (1) according to one of claims 1 to 4, characterized in that the first lateral surface (3) and the second lateral surface (4) have a common first edge (7). Bullet-resistant composite (11) consisting of ceramic elements (1) according to one of claims 1 to 5, characterized in that the first lateral surface (3) and the base surface (6) have a common second edge (8). Bullet-resistant composite (11), consisting of ceramic elements (1), according to claims 5 and 6, characterized in that the first edge (7) and the second edge (8) have a rounding (9). Bullet-resistant composite (11), consisting of ceramic elements (1), according to claim 7, characterized in that the roundings (9) are arranged orthogonally to the course of the first edge (7) or the second edge (8) and tangential transitions to the Have edges (7) or (8) forming surfaces (3), (4) and (6). Bullet-resistant composite (11), consisting of ceramic elements (1), according to claim 7, characterized in that the roundings (9) of the first edge (7) have a radius of 1/20 of the diameter (d). Bullet-resistant composite (11), consisting of ceramic elements (1), according to claim 7, characterized in that the fillets (9) of the second edge (8) have a radius of 1/40 of the diameter (d).

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