FR2494832A1 - SHIELDING WITH A MULTIDIRECTIONAL STRUCTURE - Google Patents

Abstract

MULTIDIRECTIONAL STRUCTURED SHIELDING. THE SHIELDING IS CONSTITUTED, AT LEAST PART, OF A MULTIDIRECTIONAL STRUCTURE SHAPED BY RIGID ELEMENTS 1, 2, 3, 4 ORIENTATIONS FOLLOWING AT LEAST THREE DIFFERENT DIRECTIONS. THE ELEMENTS ARE CROSSED REGULARLY. THEIR DIRECTIONS ARE NOT ALL PARALLEL TO THE SAME PLANE AND MAKE ANGLES BETWEEN 30 AND 90 BETWEEN THEM. THIS SHIELD IS SUITABLE FOR PROTECTION AGAINST THE MECHANICAL AND PHYSICAL EFFECTS OF EXPLOSIONS, PROJECTILE SHOOTING ...

Description

The present invention relates to a shielding

multidirectional structure.

  More specifically, the present invention relates to a new embodiment of shields, shields or shields intended to protect fixed or mobile equipment or personnel against, in particular, combat projectiles such as bullets or shells inert explosives, and in particular those of the

  "hollow charge" means splinters from such products

  jets or obstacles hit by such projectiles, or from fragments from other explosive devices such as

  grenades, mines or torpedoes or the rupture of

  pressure under pressure. The invention also relates to the

  protection of equipment and personnel against

  and explosive physics of pyrotechnic origin

  that or nuclear, such as blast, shockwave, X-ray flash, radiation 9, neutron flux, etc.

  A well-known means of protection is to use

  a shield made of a dense material with a high tenacity such as solid steel. This is the case for example shielding plates commonly used

  for the protection of tanks, cuirass boats

  or fixed installations. Such shielding type

  purely passive are opposed to the penetration of projec-

  by their great inertia and dispel the essentials of

  their kinetic energy by plastic deformation.

  The effectiveness of this type of shielding depends on its thickness. This must be even greater than the projectile to stop is heavier but especially that its speed is higher. The most severe cases currently known are metal jets thrown by hollow charge

  can reach 10,000 meters per second and

  inert jectiles called "A kinetic energy" or "arrows"

  whose speed can reach 2,000 meters per second.

  For example, it is known that a modern anti-tank weapon with a 105 mm diameter hollow charge projectile is capable of piercing a 60 cm thick solid steel armor. To effectively protect a tank against this type of weapon, it should be provided with such an inert mass of armor that it would no longer be able to

to move.

  Various solutions have been proposed to

  to increase the effectiveness of armor while at the same time

  mass and space compatible with the

  transport capacity of the vehicle to be protected.

  For armor to stop projectiles

  the most effective ones, such as those

  recently it has been proposed to split the mass of

  in a plurality of overlapping and independant leaflets

  to combine in the same shielding several shades of metal such as steel and light alloys and

  possibly to be inserted between these metal sheets

  one or more substances with physical and mechanical properties different from those

  such as, for example, ceramic materials or

plastics.

  In the case of shields more specifically intended

  to stop inert projectiles of a relative caliber

  such as pistol bullets, rifles,

  of machine guns or various fragments, it is known to

  mainly using a composite material of

  formed layers of fabrics based on natural or synthetic high tenacity fibers, these layers of fabric being impregnated and bonded together by a thermosetting resin type. The effectiveness of

  Such shields come from their ability to dispel the

  the kinetic energy of the projectile as a result of

  composite in a large area around the point of impact. Some versions of such shields are

  coated on the surface with plates made of ceramic

  such as sintered alumina which has the effect of

  foam the tip of the projectile, possibly provoking

  break up and thus reduce its power to penetrate

  tration. Such shields are used for example for the protection of pilots of aircraft or helicopters. They

  are then integrated into the cockpit seat.

  Finally, we know another type of shield of

  protection for the personal protection of the person

  and known as "bulletproof vest". Celui-

  it must be light and flexible enough not to

  through the movements of the wearer. One of the models

  the most recent and the most successful are

  killed mainly by a very thick and compact fabric with a three-way structure and made from a

  textile fiber with very high tenacity. This fabric is normal

  used as without any impregnation.

  The present invention aims to provide a shield that can be used both for the protection of fixed installations or vehicles against

  assaults of any kind that they may be subject to, and especially

  the anti-tank weapons, only for personal protection

  against light firearms or other shards.

  This goal is achieved by armor which, in accordance

  According to the invention, at least in part is formed by a multidirectional structure formed by substantially rigid straight-oriented elements.

  following at least three different directions and

  crossing in a regular way, the directions of the elements not being all parallel to the same plane and making

  between them angles between 30 and 900.

  By regular interweaving we mean here a

  relatively regular arrangement in the space of

  same orientation and a relatively

  in the structure between the elements of the diver-

its orientations.

  Preferably, said structure is compact, that is to say that the ratio between the volume occupied by the elements and the apparent volume of the structure is as high as possible for elements of given shapes, dimensions and orientations .

  According to a particular embodiment

  of the invention, the multidirectional structure is formed by rectilinear rigid elements oriented

  following four different directions.

  The elements may have a transverse section

  dirty of any form. However, this form is

  usually circular or polygonal.

  The diameter of the cross-section of the

  ments or the circle circumscribed in this section may vary

  depending on the intended use for the shielding and the nature of the constituent material of the elements. As a general rule, this diameter is between a few tenths of a millimeter and several centimeters, for

  for example between 0.5 mm and 5 cm.

  In the sense of length, form and

  the cross-sectional dimensions of the elements can

be constant or variable.

  The elements can be solid rods or bars.

  It is also possible to use

  which may be empty or filled with a material

  different, possibly from an active ingredient. By

  active material means a material that can react violently either alone, such as an explosive, or with another product constituting the shielding or from a projectile received by the shielding. Possible coombinations are, for example, ammonium magnesium nitrate or nitrogen-titanium peroxide.

  The constituent material of the elements of the structure

  ture is chosen according to the destination of the shield.

  It could be a metal, such as steel, tungsten

  tene, .., a ceramic, a glass, a wood, a

  plastic material, a composite material, a material

  active re as defined above, .....

  To achieve the shielding, we can use the structure as it is. The cohesion of the structure is then ensured by the fixing on a support in the form of a plate or sheet of the ends of the elements.

  defining the face of the structure adjacent to this

  port, or by linking the elements to each other at the

  of their intertwining. This link can be realized

  by means of an adhesive, for example by immersing the structure in a polymerizable resin, removing the

  structure and dewatering before polymerization thereof.

  The structure can also be associated with a

  fill, or matrix, which fills the spaces

  between the elements of the structure. This subject of

  pleating is for example metal, ceramic, glass, cement, a plastic or rubbery material,

  a composite material or an active material.

  For the same shield, it will be possible to use

  materials to realize the elements of the structure

  re or the possible matrix, the elements may have different shapes and sizes in different parts of the shield. These variations of materials, shapes or dimensions can be made uniformly or not, for example from one side to the other of the shielding. Thus, a shield may consist of several layers

  with different structures.

  We can still consider alternating, in a

  shielding, layers with a multidimensional structure

  rectional according to the invention and layers

  made in another way, for example masks

conventional sives.

  As mentioned above, in the form of reali-

  preferred embodiment of the invention, the multidirectional structure

  the basis of the armor is formed by

  the regular and compact interweaving of four

  of rectilinear elements oriented along four

  rections of space. An element of mutual arrangement identical to that of the elements constituting the reinforcement structure for materials may be adopted for the elements.

  composites described in French Patent No. 74 24243.

  This structure is commonly referred to as 4D.

  In the 4D structure, when made in its balanced form, the four directions are oriented like the four large diagonals of a cube so that each of the directions makes an angle of

  700 1/2 with each of the other three.

  This preference for the 4D structure

  not be considered exclusive. The multi-structure

  directional made of rigid elements constituting the base of the shielding can be a structure comprising only three bundles of elements and known under the name of 3D, or a structure comprising more than four beams

  such as that defined in the application for

  French Patent No 78 13.415 and its certificate of addition 78 34953,

  or in French Patent Application No. 78 16610, or a

  derived from the 4D structure by progressive curving

  the orientation of the elements, such as the one described

  te in French Patent No. 78 09103. In each case, the structure is formed by a regular interlacing

  rigid elements substantially rectilinear.

  The following examples illustrate

  not limited to various embodiments of a shield

according to the invention.

  Referring to Figures 1 to 3 which illustrate an embodiment of a multidirectional structure

  for a shield according to the invention and two devices

  this structure for testing.

EXAMPLE 1

  The shielding is carried out by means of the balanced 4-structure 10 illustrated in FIG. 1. This structure is formed of rods 1, 2, 3, 4 oriented in parallel.

  to the four big diagonals of a cube. The stems of o-

  different meanings make angles between them

equal to 70 1/2.

  This balanced and compact 4D structure has been

  made by means of metal rods with circular section

  diameter 2 mm diameter steel Stub. It had a density of 5.300 kg / m 3. This structure was

  submitted as such, that is to say without a matrix, to a

  perforated by a hollow charge to evaluate its effectiveness compared to a conventional solid steel shield with a density of 7.800 kg / m The perforation test consists in subjecting the armor to be tested to an attack perpendicular to its surface by a hollow charge of a caliber of 62 mm whose front face is located 12.4 cm from the surface of the shielding. In these conditions solid steel is perforated

on a depth of 40 cm.

  For this test, the 4D structure whose thickness was only 5czm was placed in front of a block of steel 20 (solid figure for measuring the residual energy of the metal jet from the hollow charge / in case perforation

  complete 4D structure. The orientation of the structure

  was such that the directions of two of the four

  metal rods were parallel to the surface.

  this exposed to the hollow charge, the directions of the two

  other beams making angles of 54 3/4

port to this surface.

  After firing, the 4D structure was completely

  perforated as well as the solid steel block on a deep

  23.5 cm. This result shows that the 5 cm of

  4D structure have an effect equivalent to 16.5 cm of solid steel and therefore this shielding allows a 70% thickness gain compared to solid steel and, given its lower density, a weight gain of 79%. The density of a shield is the ratio of its density to its thickness or, which amounts to the same, it is the shielding mass required per unit area to ensure

protection.

EXAMPLE 2

  A balanced and compact 4D structure was achieved by means of 8 mm circular section bars made of mild steel. It had a density of 5,300 kg / m3. This structure was immersed in a

  epoxy resin which was subsequently polymerized

  thus forming the matrix of the composite shielding material whose density was then 5.650 kg / m 3.

  block of this composite was subjected to the perforation test.

by the hollow charge of 62 mm.

  For this test, the orientation of the structure 10 was such that the four bundles of bars had the same incidence with respect to the frontal surface of the block, the directions of the four bundles thus making

  angles of 35 1/4 with respect to this surface (Fig. 3).

  Under these conditions, this shielding material com-

  posite showed 18% weight gain

compared to solid steel.

EXAMPLE 3

  A balanced and compact 4D structure has been realized using 7 mm circular section bars

  of tungsten diameter. After introduction of a matri-

  this epoxy resin composite material had a density of 13,400 kg / m. A block of this material was subjected to the perforation test by the hollow charge of 62 mm. For this test, its structure was arranged in a manner identical to that

of the block of Example 2.

  Under these conditions, this composite armor has

  showed a gain in thickness of 42% compared to solid steel, but given its higher density

  the surface mass was identical to that of steel.

EXAMPLE 4

  A balanced and compact 4D structure has been

  carried out by means of bars with a circular section of 7 mm.

  of diameter in glass. After introduction of an epoxy resin matrix this composite shielding material had a density of 2,000 kg / m. Two perforation tests by the hollow charge

  62 mm were made on this material.

  For the first test, the structure was

  in a manner identical to that of the block of Example 1.

  Under these conditions, this composite armor has

  There was a gain in surface mass of 78% compared to solid steel, but given its much lower density, the gain in thickness was only 13%.

  For the second test, the structure was

  in a manner identical to that of the block of Example 2.

  Under these conditions, the weight gain and thickness gain were respectively 78% and

  13% that is to say the same as the first test.

EXAMPLE 5

  For a material intended more particularly for the protection against the effect of the flash X coming from a

  nuclear explosion, a carbon-carbon composite was used

  carbon with 4D structure, with a density of 2,000 kg / m 3, made from pultruded rods

  1 mm in diameter and densified by impregnation and car-

  Pitching under pressure. The composite was

  violent shock waves produced by explosives and simulating the solicitation that the

  material under the effect of flash X. This composite has

  festé an exceptional resistance compared to the others - 10-

  materials envisaged for use.

EXAMPLE 6

  For the protection of the Dersr.nne1..r.t. re -

  bullets and flakes, we use a stret t: u _'- :: -

  [0019] Preferably, the structure 4D or the structure is shown in FIG. 6 of the above-mentioned coating application nr-.4. This structure can be r.u. e chopsticks of a lower diarmeter c - = .2

  made of a unidirectional composite.

  an epoxy resin matrix su er. Stne. _ s -: -

  ture can be associated with a ze-e-zue coating.

- he -

Claims (11)

  1. Shielding protection against, in particular,   jectiles and mechanical and physical effects of explosion characterized in that it is constituted, at least in part, by a multidirectional structure 1 1 e formed by rigid elements substantially rectilinear oriented   following at least three different directions and   crossing in a regular way, the directions of the elements not being all parallel to the same plane and making   between them angles between 30 and 900.   Shield according to Claim 1, characterized   in that the structure is compact.   3. Shield according to any one of revendica.   1 and 2, characterized in that the multi-structure   Directional is formed by rigid   lines oriented in four different directions.   4. Shield according to claim 3, characterized in that the rectilinear rigid elements are oriented in directions parallel to the large diagonals of a cube.   5. Shield according to any one of the claims   tions, characterized in that a matrix replaces   folds the spaces between the elements of the multi- directional.   6. Shield according to any one of the claims   preceding, characterized in that the elements of the structure have a circular or polygonal cross section.   7. Shield according to any one of the claims   tions, characterized in that the diameter of the circle circumscribes the cross section of the elements   of the structure is between 0.5 mm and 5 cm.   8. Shield according to any one of the claims   tions, characterized in that the structure has tubular elements. - 12 -   9. Shield according to claim 8, characterized tubular   in that the elements / are filled with a different material   rent of their constituent material.   10. Shield according to claim 9, characterized in that said different material is an active material.   11. Shield according to any one of the claims   tions, characterized in that it includes, in   different layers, at least one of which said multidirectional structure.