CA2592760C - Reactive protection arrangement - Google Patents

Abstract

The invention relates to a reactive protective device that does not cause end-ballistically relevant splintering for an object to be protected, characterized in that two pyrotechnic layers (2, 3) slanted in the active area of the threat are placed on both sides of a rigid or flexible, single layer or multilayer support (4) of any shape so that shock waves and reaction gases are formed once both layers are ignited and these shock waves and reaction gases are accelerated at a very high speed at an angle both against as well as in the direction of the penetrating threat in such a manner that the pyrotechnic protective surface is in a dynamic balance for almost the entire active time.

Description

REACTIVE PROTECTION ARRANGEMENT
BACKGROUND OF THE INVENTION
1. Field of the invention The present invention concerns pyrotechnic protection and in particular a fragment-free reactive protection arrangement in relation to hollow charge threats.

2. Technical background By virtue of their very high level of penetration power the anti-tank defense hand weapons (ATDHW) equipped with a hollow charge warhead represent a high level of threat in particular in relation to lightly or medium-heavily armored vehicles. In that respect the Russian PG-7 in out-of-area uses is increasingly proving to be a battlefield threat which is basically to be taken into consideration as that weapon system is very widespread on a world-wide basis.
Protection for light and also medium-heavily armored vehicles in relation to anti-tank defense hand weapons of that nature is only very limited or no longer possible, with conventional reactive and in particular passive protection systems, because the useful load of the vehicles is limited and the weight in relation to surface area of the armoring, which is necessary for protection, is too high. The lighter vehicles have only thin wall thicknesses as the basic vehicle protection is usually only designed in relation to small-caliber armor-piercing munition of a caliber of up to 14.5 mm. Therefore, various protective systems which are reactive, that is to say which act with explosive, have been developed in order to reduce the weight in relation to surface area, which is required for such protection.
For example the hollow charge protection of medium-armored vehicles with a basic protection of about 30-50 mm armor steel equivalent with passive protection systems requires an additional weight in relation to surface area of the order of magnitude of 500 kg/m2 and with previously known reactive protection systems which are already powerful, it still requires an additional weight in relation to surface area of the order of magnitude of 300 kg/mz in relation to the threats presented by ATDHW.
Thus, since the beginning of the Seventies, both in relation to hollow charges (HC threat) and also in relation to inertia projectiles (KE-threat), arrangements are known in which pyrotechnically accelerated elements provide for lateral disruption of the hitting or entering or penetrating threat and thus a reduction in the penetration power. Upon initiation by the impacting threat such arrangements are referred to as reactive protection while in the case of controlled firing they are referred to as active armoring. Reactive arrangements quite predominantly involve single-layer or multi-layer covering, at one or both sides, of the explosive with mostly metal plates. Arrangements of that kind, with suitable dimensioning, are effective both in relation to hollow charges and also in relation to KE projectiles and are in use on a world-wide basis as protection modules in relation to many armored vehicles.
Reactive systems which accelerate plates suffer from the crucial disadvantage that masses of greater or lesser size have to be accelerated to speeds of more than 100 m/s, which stress both the surroundings and also the structure carrying them. Therefore reactive armoring arrangements are predominantly in the form of modules (surface elements) of a building block nature. In the case of lighter objects to be protected or when thinner structures are involved, the use of reactive components is severely restricted or is not possible, precisely because of the loading due to the system itself. That applies in particular in regard to arrangements against KE threats as relatively large masses have to be accelerated in order to reduce the power thereof. In the case of reactive arrangements in relation to hollow charges, the required disruption masses are admittedly considerably less, but in return very much higher speeds are required in order still to reach the hollow charge blasts impinging at up to 10 km/s, with laterally effective disruption masses.

Arrangements are also known which disrupt the hollow charge blasts during penetration directly by means of explosive layers or by electrical fields, deflect them and thus implement a reduction in power.
Arrangements of that kind, when using explosive, are linked to the use of considerable explosive thicknesses in order to maintain blast-disrupting conditions over a prolonged period of time (caused by the blast length to be disrupted). Explosive layers admittedly fire very rapidly when hollow charge blasts penetrate thereinto but nonetheless in the case of conventional sandwich arrangements, even with a relatively large angle of inclination in relation to the penetrating blast, they do not provide directed lateral blast disruption, in particular in the front region. That is only achieved if there is an inclined, virtually free explosive surface which is possibly combined with a supporting (tamping) wall. Pure, comparatively thick powder or explosive layers or explosive foils applied to a plate or wall are used in a series of known arrangements. These basically involve reactive arrangements of conventional configuration with an explosive covering at one side.
Although detonation of the explosive takes place very quickly in the case of hollow charges, nonetheless a certain period of time is required to build up a pressure field as the penetrating particles cause the target material involved to be initially mechanically accelerated in an approximately hemispherical configuration away from the penetrating blast tip. That firstly gives rise to a hollow space through which a more or less large part of the tip region of the blast, which is particularly effective because it is very fast, can pass without being disrupted. That region however is crucial in regard to the residual effect of the HC threat and thus determines the degree of efficiency of the defense or the expenditure required for reducing power.
Corresponding considerations apply in regard to covering the explosive layer with plates which are to be accelerated. Not only do they have to be accelerated by shock waves and gas forces, but they also have to bridge over the crater formed by the blast tip in order to be able to laterally reach the penetrating blast. The structure of the arrangement and in particular the angle thereof with respect to the penetrating threat are here the crucial parameters. In the case of a series of known arrangements, the attempt is made, by means of multi-layer reactive protection structures which are in part heavily inclined, to minimize the above-described detrimental effects of crater formation. In general however that results in structures with a great deal of explosive or modules with a small effective protection surface area and of a structural depth which is great in comparison with the surface area which is covered.
In addition that gives rise to negative edge influences and inadequate overlaps. In addition there is an increase in the proportion of dead masses causes by the structure involved. Such masses which do not serve directly for affording protection power, in all previously known reactive protection arrangements, represent a considerable proportion of the required mass in relation to surface area and correspondingly reduce the protection efficiency.
Reactive protection arrangements are also known which are disposed in front of the structure to be protected and the aim of which is to reduce the negative mechanical or terminal-ballistic accompanying phenomena on the surrounding area, by means of suitable explosive coverings. Such structures which are generally multi-layer and generally also complex involve an operative procedural configuration, which is difficult to understand and manage, in respect of the individual components and the co-operation thereof. They have admittedly proven to be definitely effective in relation to hollow charges, but basically they are subject to the above-discussed limitations in terms of effect and evaluation criteria.
Previously known powerful reactive protection systems cannot provide a complete defense against the HC threat even by the use of considerable masses in relation to surface area as only a given proportion of the hollow charge blast can be influenced by the disruption measures.
Therefore usually between about 20 and 30 percent of the power of the hollow charge munition is compensated as a residual power by the basic armoring of the vehicle.
There are a series of disadvantages as a counterpart to the weight advantages of reactive arrangements, over passive protection arrangements. Thus conventional reactive protection systems act predominantly on the basis of the principle of flying plates which on the one hand severely endanger the area surrounding the armored vehicle and which on the other hand impinge on the structure with the plate which is flying towards the vehicle wall. That is an aspect of very great significance, particularly in the case of more lightly armored vehicles.
A series of armoring arrangements of that nature are known. The accelerated plates in that case preferably consist of steel, as described for example in EP 0 379 080 A2. In accordance with that disclosure the reactive protection is combined with an additional passive protection in order to compensate for the part of the hollow charge blast which is not sufficiently reduced by the reactive protection.
US-A-S 824 951 describes a reactive armoring arrangement in which the inert plates surrounding the explosive comprise different materials. The plate which is accelerated towards the hollow charge blast is of glass while the plate which flies with the blast towards the vehicle to be protected consists of steel. A hollow space is present behind the plate flying with the blast in order not to disrupt the movement thereof for the period of interaction with the hollow charge blast.
US-A-4 741 244 describes a reactive armoring arrangement in which a hollow space is provided behind the plate which is flying towards the vehicle. That disclosure provides that the protection action of the rear plate is greater than the plate which is flying towards the blast. The rearwardly flying plate of steel moves at very high speed so that a correspondingly heavy basic protection must be mounted on the vehicle so that the vehicle wall is not penetrated by parts of the reactive protection.
DE 37 29 211 C1 describes a reactive protection arrangement in which inclinedly arranged sandwich structures in the vehicle direction are combined with a layer-wise structure of explosive and brittle materials such as for example glass. The structure is intended to act against the front part of the hollow charge blast which, by virtue of the inertia of the inert plate members, almost unimpededly penetrates the reactive protection mounted in front thereof. The described arrangement also involves a high level of loading due to the parts impacting against the vehicle.
DE 199 56 297 C2 describes reactive protection in relation to hollow charges, in which, in layers arranged inclinedly with respect to the bombardment direction, explosive is covered on the bombardment side over the surface thereof with disruption layers of fiber composite material for avoiding hard fragments. At least one disruption layer is formed from a high-strength fiber composite material in the form of a flat textile structure comprising synthetic or renewable raw materials or a combination thereof.
DE 199 56 197 A describes a conventional reactive armoring arrangement in which only the usual metallic component, for avoiding structural and surrounding area damage, is replaced by a non-metallic plate (preferably of fiber composite material). The protection action in relation to HC and KE threats is achieved by the acceleration of one or more such plates, the reactive arrangement being disposed in a non-metallic housing. The depicted function of an additional plate which is referred as a buckling plate cannot be understood.
US-A-5 637 824 concerns a conventional reactive composite armoring arrangement with an explosive layer and a metallic plate which is accelerated in the direction of the threat. Due to detonation, in a relatively thick, dynamically acting layer which follows the explosive layer and which is supported rearwardly by means of a metallic plate, the HC
blast is reduced in respect of its power by blast disruption. The dynamic effect of the intermediate layer can be enhanced by a layer introduced into the active zone and by a further explosive layer in front of the rear metallic plate. That arrangement is based on the effect, described in the literature, of the so-called "crater collapse" (dynamic collapse effect).
Materials referred to for the production of that effect are practically all liquid, metallic or non-metallic materials - of which most however do not have any physical effect of that nature. The situation is also described, wherein the front tamping or support is only formed by a non-metallic protection layer, in which case then an increased thickness of explosive is required to produce the internal pressure required for a dynamic effect.
After detonation of the first foil the structure again represents a conventional reactive armoring with an explosive layer covered on both sides. In addition both the surrounding area and also in particular the structure are subjected to loadings and stress.
DE 37 29 211 C involves a conventional reactive sandwich arrangement (metallic plate with an explosive intermediate layer) which is embedded into hard foam in a particular fashion. That first active layer is followed by an explosive layer with subsequent brittle body structure (glass body) with separation layers of explosive. The whole complex arrangement is disposed in a metallic housing. In principle therefore the described arrangement represents a relatively thick pre-armoring with inclinedly disposed reactive sandwich structure comprising explosive-accelerated steel plates, the intermediate spaces being filled with hard foam. The powerful blast tip which as is known passes practically without disruption through arrangements of that kind is to be caught in the following layer of a dynamically supported or tamped glass body structure.
WO-A-94/20811 also involves a conventional reactive arrangement with two explosive layers which are inclined relative to each other and which are covered on both sides, in a massive metallic housing. The subject of the invention was not the conventional reactive sandwich arrangement with metallically accelerated plates, which was presumed to be known, but the way in which they are arranged in a massive housing.
That structure provides both protection from HC threats and also from KE
threats. Such structures are used in a series of armored vehicles of Soviet origin.
A basic problem in terms of the reactive sandwich protection arrangements, in particular in relation to KE threats, lies in the initiatability of the explosives used, when relatively thin covering layers are involved, as are required for reasons of the required low level of energy density because of the shock loadings on the protection or housing structures.
Therefore the aim of the arrangement described in DE 33 13 208 C is to implement blast disruption comparable to that of the so-called crater collapse, by means of a porous or foamed layer, which is introduced into a conventional reactive armoring arrangement, with incorporated explosive component. That layer is covered on both sides with metallic plates in particular to afford protection in relation to KE threats and thus again represents a reactive structure of conventional type.
DE 102 50 132 A concerns protection arrangements in relation to blast-producing and projectile-forming mines, but not in relation to hollow charges. In that case the protection effect is afforded by way of containers with a filling agent comprising a liquid or a fluid medium.
Basically this involves a protection structure which admittedly acts dynamically, but not a reactive arrangement for defense in respect of HC
threats.
It can be deduced from the above-outlined description relating to the state of the art for reactive protection systems that the previously known reactive systems are still relatively heavy and require a comparatively high level of basic protection to compensate for the residual power. In the case of ATDHW this still corresponds to a required basic protection of the order of magnitude of between 60 and 80 mm armor steel equivalent.
SUMMARY OF THE INVENTION
The object of the invention is to also protect medium-heavily and even only lightly armored vehicles with correspondingly slight basic protection in relation to hollow charges, in particular in relation to medium-caliber hollow charge projectiles such as for example PG-7, without in that respect involving additional, ballistically operative fragments. HC protection of that kind for lightly armored vehicles requires:
- a very high level of effectiveness in respect of the protection arrangement, a low weight in relation to surface area with at the same time minimum residual power;
- the vehicle wall is not to be unacceptably heavily loaded or penetrated either by the threat or by parts of the protection system;
- there is not to be any fragment loading in the area around the vehicle by virtue of the protection system;
- the mobility of the vehicle is not to be limited, possibly it must be possible to fit or remove parts of the protection system during a mission;
- the respective on-road authorization regulations (for example in Germany the "Strassenverkehrs-Zulassungsordnung", abbreviated to StVZO) must be complied with;
- there is not to be any danger going beyond the protection system due to the explosive on the vehicle, that is to say in Germany for example Classification 1.4 in accordance with the Hazardous Materials Regulations ("Gefahrgutverordnung", abbreviated to GGVS); and - when the protection is mounted, rapid access to hatches and stowage spaces must be possible.
In accordance with the present invention that object is attained in that at least two layers of a pyrotechnic material of the same or also different quantitative relationships and/or thicknesses are arranged at a spacing from each other freely or in a housing of a non-metallic material such as for example rubber at an angle to the bombardment direction. Advantageous configurations and developments of the invention are subject-matter of the appendant claims.

In a preferred configuration that pyrotechnic protection structure comprises a carrier of any desired configuration which is inclined in the impact region or region of action of the threat and to which pyrotechnic layers are mounted on both sides. Due to firing of those layers shock waves and reaction gases are formed and accelerated both in opposite relationship to the direction of the penetrating threat and also in the direction thereof. In that way, in relation to hollow charges, both the front powerful blast elements and also a decisive part of the total blast length are disrupted and thus lose their penetration power. The pyrotechnic structure in that case is disposed over the entire period of action at least approximately in a condition of dynamic equilibrium and does not exert on its surroundings any influences which are destructive or relevant in terminal-ballistic terms, that is to say either on the outside region or on the structure itself which is to be protected. In that respect the size of the required presented region is afforded on the basis of simple kinematic considerations in respect of the penetration process.

According to another aspect there is provided a reactive protection arrangement without fragment formation being relevant in terms of terminal ballistics in both operational directions for an object to be protected, wherein two pyrotechnic layers which are inclined in the region of action of the threat are arranged at a spacing from each other and are arranged on both sides on a rigid or flexible, single-layer or multi-layer carrier being inclined in the region of action of the threat and being formed of at least one metallic or non-metallic materials of very low density of less than about 30 kg/m3, such that after firing of the two pyrotechnic layers shock waves and reaction gases are formed and are accelerated at an angle both in opposite relationship to and also in the direction of the penetrating threat in such a way that the pyrotechnic protection surface made of the two pyrotechnic layers and the carrier is disposed almost over the entire period of action in a condition of dynamic equilibrium.

This involves a very simple and basic arrangement which fundamentally is not subject to any limitations or restricting technical factors. Derived therefrom is a level of innovation which is not achieved by any previously known reactive arrangement. In addition the pyrotechnic protection surface presented is suitable for affording a great increase in the level of protection in relation to a series of known armoring arrangements, both by virtue of being disposed in a frontal position in relation thereto and also by integration.

Basically pyrotechnic protection surfaces can be easily combined with arrangements for defense against KE threats. At any event, no or 10a only very small dead masses are required in regard to protection optimization in relation to a number of kinds of threat.
It will be appreciated that, in spite of the basically unrestricted freedom in terms of design configuration, a reasonable relationship in respect of the few parameters involved must be observed. In the case of conventional reactive armoring arrangements, the effectiveness is crucially dependent on dimensioning factors. In contrast in the present invention basically only a few prerequisites are to be observed, which in addition still apply in regard to all reactive arrangements. These include for example the minimum explosive thickness for ensuring initiation or on-going detonation. An exception is formed by the desired deflagration, insofar as that should not be attained by way of the composition of the pyrotechnic layer. Further prerequisites arise out of the geometrical conditions and the relationship between threat and protection surface dimensioning. In that respect the materials used such as for example the nature of the explosive or corresponding additions, up to the number of the protection surfaces, are to be taken into consideration.
By virtue of the high level of effectiveness, with a pyrotechnic protection surface in accordance with the invention, the explosive mass to be employed per unit of surface area can be considerably less than in comparison with previously known reactive armorings, as far as 50% if the above-indicated limitations are observed. As an indicative value in regard to that structure, the thickness of the explosive coverings, with an angle between the defense region and the threat of over 30 , can be about 50%
of the mean blast diameter.
Fundamental considerations regarding the speeds which can be achieved in relation to free and covered explosive surfaces can be set forth by way of the Gurney equation for flat pyrotechnic surfaces:
vl = (2.E) .5 . ((1-A+A2)/3 + b-A2 + a)- 5 with a = M1/C and b = M2/C and A = (1 + 2*a)/(1 + 2*b);
M/C: ratio of the mass of wall and explosive;

index 1: front surface, index 2: rear surface;
(2-E) .5: Gurney factor (here assumed as 2,800 m/s);
v2 = A'vl.
In the case of a virtually single-sided covering a or b becomes equal to zero.
The following Table calculates some dimensions which emphasize the fundamental considerations involved. In this respect the important consideration is not the absolute value but the clearly apparent confirmations of the consideration in connection with the present invention (D: thickness, M: mass, S: sandwich).

M 00 .-i m CO 00 N N CO
00 00 m 00 m Ln -4 ri N N 00 It N t0 .D
N 00 00 m 00 +-i c 'ri- Ln d' r-I It M Ln O O
> E M -I m M -1 0 m N Ln M M 't M N

M 00 .--I M 00 to m 194- N +-I lq- 0 0) N N 00 N 00 00 m 00 M 0) O O It +-i 0 It I- N / 0 .-i co 00 M 00 +-i N N N M M t0 In O O
> E m r-i m m It N M M m M It N 11, M N
O O O O O O .-i +-I N N N CO O O O O
O O O O O N N r-i O O O O .--I O O O
. . . . . . . . . . . . . .
< -I O O O O O O O

O O
O~ M O~ m k0 Ln M N N O c M In Ln O O *-I O O N N Ln In Ln O N N
.-1 O O O O O O M N +--I Ln ~O 0 0 O O O
M c l0 N N N N N N N Ln m Ln Ln O c ri O O M M M M M O O t0 O N N
. . . . . . . . . .
(6 +--I O O 0 0 O 0 0 O O O O 0 O O O O
N N M l0 N Ln M E O 0 O 0 0 M 0 ^ O O O N d> O t0 J
cn l0 l0 l0 l0 ,--I ri N ri L() Ln N Ln ,C r-i r-i .-I ri ,-I N l0 ri ri 00 r-4 +-I ri O 00 N
N
E N 0 l0 t0 N Ln Ln 0) 00 [t - 't d' r-i m N m o Ln M
O 00 CO 00 06 ri M l0 CO N CO M 0 ra N O
E 0 0 O Ln Ln Ln N M 00 00 O O 0 N Ln In 0) 00 l0 N CO 00 CO
O N N N N Ln N Ln 00 Ct N N N O .-a M
M
N E Ln Ln Ln 0 0 00 00 co CO co 00 00 00 00 00 00 00 00 Ln Ln Ln i 0)0) N N N N N N N N N N r l%' N

ri ri N O N
E
O O O O O O r-i N M O O O
N
E O O O O O O
U cn O O Ln Ln Ln Ln Ln Uf Ln N N N O O O
~C M M ,i M N N N N N ri ri ri l0 110 0 M
U E
0 0 Li) Ln Ln m Ln Ln Ln Ln Ln Ln N N N N N N
- 0) ri .-i ri ri v-1 .-i r-i r-i r-i ri r-i ,-i .-i .- .-i ri U E N N Ln Ln Ln Ln Ln Ln Ln Ln 0 v 0 O +-i N M 0 O 0 O 0 ri ri ri 0 O 0 N
E
{ M 00 00 O 00 O CO OJ O co M co 0n N LP) Ln - O N N N N N N N N N 0 '0N O +-i c M
r-i E Ln Ln 0 0 00 00 O 00 00 00 00 00 00 00 00 00 00 Ln Ln Ln 0) N N N N N N N N N N N t~ t~ +-I . i d ri ri ri O ri O O
E Q rI r-( r-I r-I rI rI rI ri .-i 0 0 .-i 0 .-I .-i With a relatively great thickness of explosive (DC) and a relatively thin carrier layer, the result is theoretical speeds of the order of magnitude in respect of the blast speed of up to over 4 km/s. The free surface or a slight covering in respect of the explosive surface decides on an approximation to the theoretically attainable speeds.
When very thin coatings are involved (protection of the foil surface) of the order of magnitude of 0.1 mm, very high surface speeds (over 3 km/s) are achieved, even with very thin explosive foil thicknesses (for example 2 mm - the minimum thickness is determined by the firing properties). The surface speed already falls to below 2 km/s with coverings which are still very thin (for example 1 mm Al). It is however still very high in comparison with conventional sandwiches.
In a situation involving single-sided or virtually single-sided covering, average explosive thickness and relatively massive wall (for example for KE protection or for system reasons), wall speeds of the order of magnitude of only 50 m/s are afforded when realistic dimensionings and very high single-sided speed are involved. Such low speeds are still to be controlled with mechanical means. Accordingly, for this limit region of constructions according to the invention, there are particularly attractive combinations in which a high level of protection efficiency is combined with a very small structural depth and without burdening the surrounding area and structure.
The following fundament arrangements are considered by way of example in connection with configurations of the carrier in accordance with the present invention (see Figure 4 and Figure 5):
Figure 4A: symmetrical covering by means of pure explosive foils.
It will be appreciated that this also includes foils with surface treatment or surface protection. This results in detonation which is simultaneous in a first approximation. The "dynamic tamping" due to the detonation gases increases the effective tamping mass and the result is a maximum surface speed of the order of magnitude of the blast speed. The wall itself, by definition, does not experience any acceleration. The speed of the reaction gases can be considerably influenced by the foil configuration and the explosive selected, and likewise by substances introduced into the explosive matrix. When the explosive layer is covered with a massive layer, as is quite predominantly the case in conventional sandwich structures, that influencing option is severely limited.
Figures 4B and 4C: differing explosive covering. This affords a resulting speed in respect of the separating wall or the carrier respectively. With a suitable configuration and an appropriate choice of material, this basically does not signify any limitation in terms of the use bandwidth. Almost complete symmetry of the overall reactive arrangement is then to be achieved by a symmetrical arrangement of two surfaces. In a first approximation, the difference between the two explosive foils can apply as the starting point for roughly estimating the resulting acceleration of the carrying layer or the connecting layer, either in the direction of the threat or in the opposite direction to the threat.
Figure 5A: disposed between the pure explosive foils is a more expanded wall (for example of very low density of the order of magnitude of 0.1 g/cm3). That wall can also be of a dynamically relatively hard nature, with high compressibility.
Figures 5B and 5C: the explosive foils in the structure corresponding to Figure 5A are covered either on the wall side (carrier side) or on the outward side (threat and object side) by a very thin layer.
In accordance with the foregoing Gurney considerations, that permits adjustment of the desired blast propagation speed on that side. Thus for example it is also possible in the range of small surface coverings to attain a prolongation of the duration of engagement in relation to the threat.
It will be appreciated that the explosive foils or also the coverings may be of variable thicknesses. In that way for example it is possible to influence the effectiveness of a surface portion, for example to compensate for different protection depths or presentation angles.
In connection with capturing the fast blast portions due to sufficiently high speeds in respect of free foil surfaces, arrangements which act very widely over the inclined surface coatings, with a high overall level of efficiency, can be afforded. A single-sided covering on the explosive foil with an accelerated plate of conventional dimensioning can then be considered as a limit case. That applies however only for that partial component of a reactive structure but not for a reactive arrangement in the sense of and as set forth in the claim of the present invention.
A thicker carrying layer or a separation layer between the explosive foils with additional physical properties, for example in respect of dynamic behavior or specific properties in relation to shock waves, can be of advantage if the depth of engagement is increased, that is to say a plurality of blast particles or a greater blast length remains involved there.
Known glass bodies which are dynamically compacted by means of explosive operate on that basis. Not least because of the required thicknesses, in terms of the mass balance of an armoring arrangement, they are however relatively heavy.
In the case of reactive armoring arrangements, the influence of the size of the elements on the tamping effect and thus on the speeds which can be achieved by the accelerated components is of great significance.
In that respect it can be readily seen that small element sizes and relatively large explosive thicknesses as well as relatively high element masses have a speed-reducing effect. For, the speed of an element of small surface area is correspondingly reduced, the thicker (increased mass) the covering is, and the thicker the explosive layer is. That reduction in speed can be of the order of magnitude of 50% so that this influence can greatly override other target-specific parameters. When very small covering masses are involved or when pure explosive layers are involved, that influence of the element size becomes correspondingly less.
In a first approximation it remains without influence on the speed of the gas blasts. That affords a further advantage in arrangements in accordance with the present invention. In particular the very important design criteria such as module size and action in edge zones are positively influenced.
A multi-layer structure for the carrier provides that the latter can also serve as a control element for energy and signal transfer between the explosive foils. A design criterion in that respect is the acoustic impedance of the materials used.
The explosive layers required in pyrotechnic protection surfaces in accordance with the invention make only slight demands in terms of manufacturing tolerances and surface quality and thus the manufacturing processes. That considerably increases the freedom in terms of the design configuration of the surface of a protection element.
A further improvement is afforded by the basically known process of covering the surfaces of the pyrotechnic layers with materials of differing density. Advantageously, for those coverings, materials of low or higher density, brittle, decomposing or delaminating materials such as glass, composite materials, ceramics or materials which are shock-hard but which are soft at relatively low deformation speeds such as for example rubber are employed here, which with their high inertia, after a comparatively long response time, dissipate or erode the middle and rear part of the hollow charge blast, over a prolonged period of time. Suitable materials of low density are for example metallic or non-metallic foams.
In the case of free explosive surfaces, air as the surrounding medium, because of its low level of inertia, achieves a short response time and very high acceleration for dissipating the fast parts from the front region of the hollow charge blast.
Geometrical alterations can be made within wide limits by virtue of application of the model rules used in ballistics, in particular the Cranz model law which was originally formulated for the detonation of explosives and later expanded to the whole of terminal ballistics. In that way a structure which is tried and tested in practice can be transferred in very wide limits to comparable uses by means of physical and geometrical representational rules. Further aids in regard to dimensioning are afforded by numerical simulations.
The high level of effectiveness of an arrangement according to the invention is basically not linked to a housing. A container, housing or covers serve primarily for fixing or protecting the active layers, also in conjunction with protection components to be combined and in relation to external influences.
In practice it is advantageous for the mode of operation of the protection arrangement according to the invention to be linked to structural factors in respect of the object to be protected. That can extend from simply stringing them together to mutually supplemental protection structures. The inert materials of the front and/or rear side of the housing comprising one or more layers can also be optimized in terms of the effectiveness in relation to KE projectiles.
In a preferred embodiment the layers of explosive and inert materials are introduced into prefabricated pockets in the protection module, whereby the reactive protection can be adapted to the vehicle to be protected, in a simple manner which is readily appropriate for manufacture.
BRIEF DESCRIPTION OF THE DRAWINGS
The Figures characterizing the invention and the description of the processes involved in relation to impacting and penetrating threats are set forth in the following list:
Figure 1 shows the basic structure of a pyrotechnic protection surface according to the invention, Figure 2 shows the mode of operation of the pyrotechnic protection surface shown in Figure 1 at a relatively early moment in the entry and penetration process, Figure 3 shows the mode of operation of the pyrotechnic protection surface shown in Figure 1 at a later moment in the entry and penetration process, Figure 4 shows examples of pyrotechnic protection surfaces as shown in Figure 1 with thin carriers, Figure 5 shows examples of pyrotechnic protection surfaces as shown in Figure 1 with expanded carriers, Figure 6 shows an example of a pyrotechnic arrangement with two free explosive layers, Figure 7 shows an example of a pyrotechnic arrangement with inner tamping, Figure 8 shows a further example of a pyrotechnic arrangement with a buckling sandwich, Figure 9 shows an example of a pyrotechnic arrangement with a container/housing, Figure 10 shows a further example of a pyrotechnic arrangement with container/housing, and Figure 11 shows a further example of a pyrotechnic arrangement with container/housing.
DETAILED DESCRIPTION OF THE EMBODIMENTS PREFERRED AT THE
PRESENT TIME
The foregoing and further features and advantages of the invention will be better appreciated from the description hereinafter of preferred, non-limiting examples with reference to the accompanying drawings.
Thus Figure 1 shows the basic structure of a pyrotechnic protection surface corresponding to the invention with the impacting hollow charge blast or the impacting threat 1, the pyrotechnic coverings 2 and 3 and the carrier 4 therebetween.

Figure 2 shows the condition or the mode of operation of the pyrotechnic protection surface of Figure 1 at a relatively early moment in the entry and penetration process. The initiation of the front (towards the threat) pyrotechnic covering 2 is effected at the impact point of 1 against 2 (small circle 5). The detonation front is propagated in 2 at a speed which is of the order of magnitude of the mean blast penetration speed in the part of the hollow charge blast which is to be defended against (symbolized by the arrows 6). In the case of a relatively thin carrier initiation is effected in the rear pyrotechnic covering 3 both by the shock waves which are propagated in a hemispherical configuration from 5 and also by the penetrating blast tip at the impact point of 1 against 3 (small circle 5A). The same conditions as in respect of 2 apply in respect of the propagation of the detonation front in 3 (arrows 6A). By virtue of the geometrical conditions and in particular also the configuration of 4, there can be an asymmetry in the control space applicable in respect of the moment in time being considered (large circle 7) for the play of forces and thus the overall dynamics. That however has no influence on the fundamental properties of the described arrangement. The detonation fronts which are propagated against the threat, consisting of accelerated reaction gases (and possibly accelerated surface layers), are symbolically indicated by the expanding pressure field 9.
In the case of free or only slightly covered surfaces of 2 and 3, there are high propagation speeds in respect of the detonation front and the reaction gases in the direction of the entering and penetrating blast (arrow array 8). The speed is also quite crucially increased by the tamping property of the surfaces 4 and 3 (prior to firing statically by virtue of the inertial mass, after firing of 3 by virtue of the pressure field which is formed), in relation to the explosive layer 2. As a result blast portions in the tip region are laterally loaded and thus deflected or destroyed. In the case of the hollow charge particles which are very sensitive to disruptions in particular in the tip region, it is sufficient for them to be acted upon with a low level of energy for a great reduction in power (destruction) of those parts.
By virtue of the above-described penetration mechanism however the foremost parts of the blast still pass through the front pyrotechnic layer 2. They are caught in the rear pyrotechnic covering 3. Because of the currently prevailing physical conditions which apply there, the geometrical relationships and the speeds which occur, in conjunction with the short reaction times, the foremost blast tip is also reached in the rear zone, so that overall the situation involves total loading on, deflection and thus destruction of a large part of the hollow charge blast including the foremost particles thereof.
Those conditions are shown in Figure 3. A part of the pyrotechnic covering 2 has already been converted into a pressure field 9A which is spreading out further. The control space for the overall dynamics, symbolized by the large circle 8A, with the corresponding arrays of arrows 8 and 10, of the reaction surfaces of 2 and 3, shows both an overall picture of the forces, which is compensated to a good degree of approximation, and also the loading applied to the foremost blast tip in the region, identified by a smaller circle 11, of the disruption field 12 formed by 3.
Figure 4 shows examples of symmetrical or asymmetrical pyrotechnic protection surfaces with carriers positioned therebetween.
They can be both protection-relevant (for example as KE protection or protection against shallow cone charges) or of an extremely light nature.
Corresponding reactive arrangements can be formed from a single element (flat or curved or any shape) or can be assembled to form a surface by the combination of two or more elements. In that way it is possible to adapt the reactive protection according to the invention to the threat.
Figure 5 shows some examples of pyrotechnic protection surfaces (here arranged symmetrically) with expanded carriers or inside surfaces 4A, 4B, 4C. As described, they can comprise extremely light materials or they can also serve at the same time as internal volumes (for example as containers) for other functions. It will be appreciated that no limits whatsoever are set on the configuration of those inner regions, provided that the mode of operation of the reactive components is not unacceptably limited.
As shown by means of structures set forth by way of example (see Figures 6 through 11) and experiments which have been conducted, single-sided and/or double-sided coverings on the explosive surfaces in the inner and/or outer regions 13, 13A, 14, 14A are of great significance in particular for the overall efficiency of an armoring arrangement, and equally for distribution of the protection that is still required, in relation to the residual penetration depth of the threat.
For an optimum protection effect in regard to reactive arrangements according to the invention, single-sided or double-sided support for one of the explosive layers can be advantageous in terms of the overall balance sheet of the protection action or in connection with factors relating to design technology. Such a support for the explosive for enhancing the overall protection effect is advantageously implemented with dissipating masses such as for example surfaces of metallic or non-metallic foils, GRP, ceramic or glass or also fluids and gels.
In accordance with the foregoing description the materials of the support and tamping means are advantageously to be so selected in respect of amount and density that, in combination with the pyrotechnic layers, one or more of the support or tamping layers is set in motion as early as possible in order to destroy the front fast parts of the hollow charge blast, and one or more support or tamping materials are set in motion more slowly so that they can destroy the slower middle and rear regions of the hollow charge blast.

The explosive layers can be embedded in one or more metallic or non-metallic materials of low density (15-30 kg/m3) and high compressibility as a matrix (see Figure 6).
The configuration of the carrier 4 is completely free. It is therefore illustrated in Figure 1 in the form of a curved surface. All that is required is a sufficient inclination relative to the threat in the region of action. By virtue of the high efficiency of the pyrotechnic covering, in the arrangement proposed herein, the minimum angle is by between 100 and less in comparison with known reactive structures. As the basic 10 starting point in the case of sandwiches of a conventional kind is a minimum angle of inclination of 45 , a mean angle between threat and defense of between 30 and 40 is sufficient with the present arrangement. The angle between the defense surface and the threat can be formed by way of the angle of presentation of the total surface or by 15 way of geometrical modifications, by means of technical or structural measures. Thus for example even in the case of a surface which is inclined too little in relation to a threat for it to have a sufficient action, the required inclination can be achieved for example by corrugation, providing an angled configuration or by laminating. In that respect the different embodiments of the pyrotechnic protection surface can form a coherent and continuous surface or can be made up from individual modules with intermediate spaces or other separations (for example surface segments, a Venetian blind-like arrangement, separate modules or modules which engage into each other).
The technical configuration of the carrier is basically not subjected to any limitations (for example metallic, non-metallic, structured, single-layered or multi-layered). The carrier can be rigid or deformable/movable and its thickness can extend from a foil thickness up to a massive plate or thicker structure. It can also comprise an inert material or a chemically/pyrotechnically reactive substance. Accordingly an inner high-pressure field can also be built up in that carrier by the detonation of the pyrotechnic coverings.
The powerfulness and efficiency of a protection arrangement is generally assessed as the ratio of the reference mass (power of the munition in armor steel equivalent) to the mass of the protection arrangement itself, by means of two factors:
1. Em-factor, formed from: Em = mref/(mS + mRL), with mref as the power of the threat in steel-equivalent mass, mS as the protection mass used and mRL as the residual power in steel-equivalent mass;
and 2. Fm-factor, formed from Fm = (mref - mRL)/mS.
The Em-factor serves as an assessment scale for the quality of an overall protection. In the case of a partial protection measure, that is to say when there is residual power still present, assessment of the individual protection arrangements is more meaningfully effected by way of the Fm-factor in order to be able to comparatively assess the quality thereof.
The Fm-values which can be achieved in accordance with the present state of the art, for passive protection arrangements, are in the region of 5, while for reactive arrangements they are in the region of between 8 and 10.
An arrangement according to the invention basically presupposes the use of pyrotechnic substances with a dynamics corresponding to the situation of use, that is to say reactivity. Handling of the pyrotechnic elements required here and the safety precautions related thereto and other operational factors are decisively improved insofar as the necessary technical requirements for the carrier structure and the vehicle respectively can be set at an extremely low level by virtue of the described advantages. In addition the period of use of an effective pyrotechnic covering can be minimized by suitable precautions.
Figure 6 shows a structure in principle, corresponding to Figure 5A.
The hollow charge is positioned at a spacing 15 from the reactive protection arrangement. The latter in the simplest form comprises the explosive layers 16 and 17 which are inclined with respect to the blast axis 1. The layers 18, 19 and 20 serve for purely fixing the explosive layers 16 and 17. Those layers 18, 19 and 20 can also serve as very light tamping and support means. In that respect the required propagation speed of the surface however may not be substantially limited.
The protection arrangement corresponding to Figure 6 was experimentally tested at 45 with an experimental charge of type PG-7 at a spacing (15) of about 2.5 calibers. The protection structure consisted of foam/explosive/foam/explosive/foam, and the weight in relation to surface area, with a density of the foam of about 15 kg/m3, was less than 30 kg/m2 in LoS (line of sight). The experimentally ascertained residual power was about 30% of the power of the hollow charge in armor steel.
An extremely high Fm-value of over 70 is calculated therefrom. In addition, as in the following examples, terminally ballistically relevant parts are not produced either in the direction of the threat or in the direction of the object to be protected.
That confirmed that such an extremely light arrangement according to the invention is suitable as general protection in conjunction with objects to be protected generally, as additional armoring and in particular as protection for almost all vehicles. Such an arrangement is also best suited for vehicles with a high level of basic protection, in particular combat tanks, in order to protect the side and the tail from a threat by an ATDHW.
In a further experiment the front explosive layer 16 was covered with a relatively thin layer of a material of medium density. With a weight in relation to surface area of the reactive protection arrangement of about 100 kg/m2, the residual power was only about 10%. That gives an Fm-value of over 25.
If those experimentally ascertained power values are compared to values of known reactive protection arrangements, the difference in relation to the protection arrangement according to the invention becomes clear, both in respect of residual power (10% in comparison with about 30%) and also weight in relation to surface area (N 100 kg/m2 in comparison with 300 kg/m2).
In a further test both the front explosive layer 16 and also the rear explosive layer 17 were tamped on the side of the carrier with a brittle material of medium density (20, 20A) (Figure 7). By virtue of the relatively thin inner layer of foam 19, this involves a particularly shallow protection structure as shown in Figure 5B. With a weight in relation to surface area of the reactive protection arrangement of below 90 kg/m2, the residual power was less than 10%. That gives an Fm-value of over 30.
The residual power of the hollow charge must be compensated by ballistically active materials. As even materials such as armor steel, high-strength duralumin or titanium only achieve effectiveness levels of up to 1.5, the particular powerfulness of this protection arrangement according to the invention becomes clear, in particular in consideration of the use in relation to light systems. The extremely low levels of residual power achieved confirm that the use of such a reactive protection arrangement according to the invention is a possibility for medium and even lightly armored vehicles.
This was confirmed by an experiment with a reactive protection arrangement as shown in Figure 8. In that combination of the arrangements shown in Figures 5 and 6 (front covering: thin layer 21 of medium density), a buckling device 22 was arranged on the target side after an explosive layer 17 embedded in foam 19, 20. With a weight in relation to surface area of the overall protection arrangement of about 170 kg/m2 the residual power was only between about 1% and 2%.
A comparison of the absolute values of the reactive protection arrangement according to the invention with reactive protection systems according to the state of the art clearly shows this significant level of innovation. Conventional reactive protection systems with a weight in relation to surface area of 300 kg/m2, in the best case, achieve residual power values of 20% of the reference power of the threat, that is to say in the case of a threat due to an ATDHW with a power of between 300 mm and 400 mm armor steel equivalent, they give a residual power of between 60 mm and 80 mm armor steel. That corresponds to a weight in relation to surface area of between 480 kg/m2 and 640 kg/m2. In the most favorable case therefore the arrangement involves a total weight in relation to surface area for the required armor protection of 780 kg/m2. If the area to be protected of an object is for example 6 m2 (for example side protection), then a total protection weight of 4680 kg is required. In comparison the residual power of the reactive protection arrangement according to the invention is only at a maximum 10 mm of armor steel equivalent, corresponding to a weight in relation to surface area of 80 kg/m2. Accordingly, upon addition to the weight in relation to surface area of this protection arrangement according to the invention, the total weight in relation to surface area for the armor protection required is 250 kg/m2.
For the object to be protected, with a protection surface area of 6 m2, that signifies a total protection weight of only 1,500 kg, that is to say the weight saving in relation to reactive protection systems in accordance with the state of the art would be 3,180 kg. With a reactive protection arrangement according to the invention therefore only about 32% of the protection mass of conventional reactive protection arrangements is required.
The pyrotechnic covering of the protection surface can comprise both a coating, a fixed or applied explosive foil, an applied reactive mixture (for example metallic additives for enhancing the disruption efficiency) or also a rigid or deformable container (bag) containing a pyrotechnic active agent. The walls thereof however must be of such a nature that the described mode of operation of the pyrotechnic protection surface is not impaired. With covering thicknesses in respect of the fast components of the order of magnitude of tenths of a millimeter however that is guaranteed. The metallic or non-metallic casing of such a container or the surface of the explosive foil can also result from the manufacturing process. In addition such casings or surfaces can also be required for protection in relation to handling and use loadings as well as environmental influences.
Pyrotechnic protection surfaces can be easily combined in order to achieve the required defense effect for example in relation to comparatively heavy threats. Thus for example connecting together two relatively thin pyrotechnic protection surfaces forms a new, highly effective protection surface whose overall explosive thickness is always still smaller than that of the known reactive armoring arrangements. Thus even when using two pyrotechnic protection surfaces, by virtue of the further reduction in residual power, those high efficiency values are still achieved or even larger hollow charges are extremely effectively dealt with. That applies in particular also in regard to tandem arrangements.
All possible options concerning firing of the pyrotechnic surface are to be transferred from or derived from known reactive protection arrangements. That includes triggering by directly acting thereon or by way of firing aids, as far as controlled external firing. Equally, all possible options concerning cladding or encasing the pyrotechnic surface are to be correspondingly transferred or derived from the known arrangements.
That includes introduction (or packaging) in a pure protection foil (for example in relation to the influences of weather, to provide a safeguard against shock or abrasion during transport or in regard to the colored configuration of the surface).
Further advantages and possible options in respect of the configuration, which are to be transferred or derived from known reactive protection arrangements without involving particular knowledge, concern the configuration of a housing and fixing means including dismantleability and thus replaceability and mobility (pushing in, turning, tilting). That also applies in regard to positioning at a spacing from the object to be protected, by means of fixing elements or intermediate layers. It will be appreciated that they are not to impair the function involved.
Intermediate layers or spacers can involve for example thin structures, substances of very low density or air chambers. Further points concern for example modular structures, multi-layer arrangements, changes in the thickness of a carrier and pyrotechnic coverings and a variation in the active components involved. It will be appreciated that it is also possible for any layers or structures (for example curved, corrugated or angled surfaces) to be covered with a pyrotechnic protection surface on one side or on both sides.
The most highly efficient reactive protection arrangements or protection surfaces according to the invention also substantially render redundant the use of highly complex active protection technologies which are highly susceptible to trouble and disturbance. Systems of that kind are intended to afford a further increase in protection power in comparison with conventional reactive protection systems, in particular where the threat is no longer to be defended against by the object itself, even with powerful known reactive arrangements, or the object to be protected would be excessively severely stressed or indeed destroyed by the reactive armoring itself.
However even where active protection systems are provided, the reactive surfaces according to the invention can afford a crucial advantage insofar as modules of that kind, with very low masses in relation to surface area and also with an element size of any desired shape or of very small dimensions, afford high levels of protection power and efficiency.
That is relevant in particular in the case of actively accelerated protection elements as they require only relatively low levels of energy for acceleration thereof, in accordance with the very low masses involved.
Basic advantages of pyrotechnic protection surfaces or protection apparatuses are listed hereinafter:

- the pyrotechnic protection arrangement or protection surface is of a minimum weight in relation to surface area.
- the pyrotechnic protection arrangement or protection surface requires a minimum structural depth.
- the pyrotechnic protection surface is basically a free element and is thus not bound to any further technical devices.
- the pyrotechnic protection arrangement affords optimum overall efficiency in respect of mass and protection depth.
- there is no limitation in regard to an areal structure, both in terms of the configuration and also the protection depth. This means that even extremely shallow structures are possible (order of magnitude: between 20% and 30% of the HC reference penetration power in terms of armor steel).
- it is possible to embody very small element sizes as the edge influence (for example on the tamping or support means) is very much less, in comparison with conventional reactive armoring arrangements.
- the arrangement is to be adapted as desired to the angle of inclination of the surface to be protected.
- the pyrotechnic surface can be positioned as desired as a module, thus for example as a single-layer or multi-layer front armoring, as active surfaces in conjunction with skirts or also directly as a skirt.
- the HC blast is subjected to a loading in two different directions with a minimum reaction time and at the same time a long temporal extent.
- besides a generally non-problematical blast pressure, no structure loadings and stresses occur. It is possible in that way to avoid deformation in the carrier structure.
- no loadings occur in respect of all of the surrounding area, by virtue of masses which are relevant in terms of terminal ballistics.
- the pyrotechnic protection surface can be of any desired shape and can be adapted to each surface or inner structure.

the pyrotechnic protection surface can be rigid or deformable/movable.
- the pyrotechnic protection surface can be fixedly or releasably fixed to existing surfaces in any manner.
- the pyrotechnic protection surface can be suspended or clamped in the form of a rigid or movable curtain in a frame or loosely in front of an object to be protected.
- pyrotechnic protection surfaces can cover any layers or structures on one or on both sides.
- any structure of technically independent protection surfaces and combination thereof is possible. It is thus possible for example also to combine pyrotechnic protection surfaces which are parallel or inclined relative to each other.
- The pyrotechnic surface can be used as an independent device or combined with other armoring arrangements (for example in relation to KE and FK threats).
- the pyrotechnic protection arrangement can be effectively combined with buckling plate arrangements as it reduces the high blast speeds and thus increases the effectiveness of buckling plate arrangements (buckling sandwiches).
- pyrotechnic surfaces can be used as a very highly efficient multi-layer areal module for example in relation to threats of relatively large-caliber mono-hollow charges or HC tandem threats.
- the pyrotechnic protection surface does not presuppose any elevated technical demand (for example in terms of manufacturing process, manufacturing tolerances and homogeneity of the explosive).
- in comparison with the protection effect achieved the manufacturing costs of the protection surface are low.
- pyrotechnic protection surfaces afford multiple retro-fitting options in relation to existing structures, vehicles or other surfaces to be protected (including as additional armoring in relation to inert or reactive armoring arrangements which are already in existence).
- when using or by replacing reactive components, a technical improvement in the overall structure is afforded in a large number of known examples of reactive protection arrangements.
- pyrotechnic protection surfaces can be adapted to the state of the art, without involving major complication and expenditure.
- dynamic balance can be afforded even with different covering thicknesses or element masses, by virtue of suitable configuring or dimensioning of the other components.
- the carrier of a pyrotechnic protection apparatus can comprise an inert material or a hollow or filled structure.
- the carrier of the pyrotechnic protection surface can be minimized as a pure fixing or mounting surface or, depending on the respective configuration (for example multi-layered or as a technical structure) can satisfy additional ballistic or technical requirements over a wide range.
That can be done without reducing or interfering with the basic power and efficiency of the arrangement.
- all know advantages of such arrangements apply in respect of the housing or the fixings for the pyrotechnic surface.
- if necessary the side, roof and bottom surfaces of a housing or container can also be covered with pyrotechnic protection surfaces.
- by means of pyrotechnic protection surfaces according to the invention it is also possible for the first time to afford highly effective protection against HC threats in the case of light vehicles or unarmored apparatuses.
- by means of pyrotechnic protection surfaces according to the invention it is also possible for the first time to afford highly effective protection against large-caliber HC threats in the case of medium-heavily armored vehicles (for example S-tanks).

- pyrotechnic protection surfaces can be used as a supplement and/or an active component in regard to active armoring arrangements.
- pyrotechnic protection surfaces can serve in relation to active armoring arrangements both for signal transmission (detonation transmission) and also as active surfaces.
In the case of the reactive protection apparatus the respective explosive layers are selectively enclosed by one or more chambers provided with filling substances or air. Further configurations of the invention, in particular in regard to the use thereof and the suitability for employing them in relation to light vehicles or transport means are to be briefly set forth hereinafter.
A flexible housing is particularly advantageous, by which the explosive layers which are not supported or which are supported in region-wise manner are enclosed. The housing (see Figures 9 through 11) can comprise an elastic, metal-free material which does not form fragments, such as for example elastomers, thermoplastic resins or thermosetting resins. It may also comprise flexible materials such as foams or sintered materials, fiber composite materials, a material from renewable raw materials, wood or synthetic wood, an organic material (paper, leather), a textile material or a combination of such materials. When complete integration of one or both explosive layers into the housing walls is involved, that provides for dynamic tamping or support for the detonating explosive. That result in a further increase in the protection effect. In addition the explosive layer which faces towards the battlefield can be additionally protected with a composite armoring, in particular in relation to small-caliber ammunition.
The following three arrangements serve to illustrate the almost unlimited configurational options of containers or housings. Thus Figure 9 shows an example of a pyrotechnic arrangement 23 in which the housing 28 has a perpendicular rear wall. Disposed behind the thin front cover 24 is the front pyrotechnic layer 25, followed by an intermediate layer 27 .. CA 02592760 2007-07-04 comprising air or a medium of very low density. A further pyrotechnic layer 26 is disposed between 27 and the rear (filled or free) volume 29.
The reactive protection can be mounted with or without a housing directly or at a spacing on a buckling arrangement at the vehicle side.
The buckling structure comprises a front metallic or non-metallic layer, a dynamically operative functional layer, for example rubber, and a rear metallic or non-metallic layer which for example can represent an outer wall of the vehicle (for example stowage boxes etc.).
Figure 10 shows such an example of a pyrotechnic arrangement with a buckling sandwich 30 disposed therebehind. Here the pyrotechnic layers 31, 33 are set at different angles. The front explosive foil 31 is embedded into the front of the housing. The inclined rear wall 36 of the housing is of differing thickness. The space 32 is here empty in order to permit the highest possible surface speed for the foil 33 which is covered with the thin layer 27. Disposed behind the medium of low or very low density 34 is a buckling plate sandwich 35. The space 35 therebehind is either empty or filled with a medium of very low density.
Figure 11 shows an example of a pyrotechnic arrangement 38 with a housing 39 with is open on the rear side and which here is fitted directly onto the wall 40 of the object to be protected. The arrangement 38 has a continuous front pyrotechnic surface 41 while the inner pyrotechnic surface is divided into two components 45, 46 which can be separated for example by an intermediate wall 44. The chambers 42 and 43, and the chambers 47 and 48, can be filled with air or with media of the same or different, very low density.
In a preferred embodiment the layers of explosive and inert materials are introduced into prefabricated pockets on the container or housing, whereby the reactive protection can be easily adapted to the vehicle to be protected in a suitable fashion from the point of view of manufacture. Exchanging components, for example replacing pyrotechnic modules by inert modules, is also easily possible. Equally, a plurality of reactive surface portions can be combined to provide a protection surface.
Depending on the respective material used, the housing can be produced by means of vulcanization, casting, adhesive, pressing or cutting machining. It is also possible to envisage all combinations of said production processes. In addition the housing can include a pre-armoring arrangement or can represent same itself. The housing can include one or more hollow spaces of the same or different sizes, into which the inert and explosive materials of the pyrotechnic protection structure are inserted, pushed in, cast in or pressed in. The wall thickness can be uniform or can be of a varying thickness. The latter is advantageous if the housing is part of the layer operative as protection, or itself represents an inert supporting tamping means operative as protection. The housings can be of such a configuration that they can be assembled to afford a fixed or flexible contour. That arrangement of the structure prevents protection modules from being torn out in the event of the vehicle being involved in collisions with obstacles and/or under bombardment. Individual segments of that wall can be displaced, bent away or rolled up in order to make areas of the vehicle which are disposed therebehind accessible. The segments of the wall can be removed or added with few handling operations.
In a suitable configuration the housing is so designed that it overlaps with adjacent housings, at the edge regions. That ensures that even in the event of hits in the edge region or directly at the housing edge, there is sufficient barrier material. It is particularly advantageous if the housing wall in the region of adjacent housings is of a wall thickness which reliably prevents sympathetic detonations of the explosive layers of adjacent modules if a hit occurs on the module outside the overlapping region.
The fixing elements can be vulcanized onto the housing, cast thereon, secured thereto by adhesive or suspended thereon. Preferably the fixing elements comprise a material which does not form fragments and which involves a high level of toughness so that upon detonation of adjacent modules, the undetonated modules remain on the vehicle. The fixings can be reinforced by high-strength fibers and/or high-strength inlays of polymer or steel.
The housing walls are to be of a flexible design for thermal loadings (fire, radiation heat) which last for a prolonged period of time. The maximum internal pressure when prolonged loading periods are involved can be limited by structural measures on the housing so that an insensitive explosive can burn without in that situation detonatively reacting.
It is possible to arrange in the housing one or more chambers which are separated from each other and which are delimited by the explosive layers, the respective matrix material and the housing material, in each case alone or in combination. Those chambers can be filled with materials which break up and which do not form effective fragments such as for example gases, solids, liquids, gels, crystals, fibers or loose material. The cavities in the wall or in the housing can be used as containers for fuels or working substances, fluids or also as a stowage space, for example items of equipment. Those cavities in the housing can also be subjected to the effect of pressure with gases or liquids in order to move the reactive HC
protection according to the invention from the space-saving transportation position into the defense position.
The housings can be so arranged that they form interconnected columns which are rolled up or pivoted together individually or in pluralities for maintenance operations on the vehicle. The housing or parts of the housing can also be designed at the same time as packaging means for the explosive for storage, handling, carrying on the vehicle and transport in accordance with the GGVS ("Hazardous Materials Regulations"). To avoid an internal pressure which is critical in regard to reaction of the explosive, defined diaphragms or excess-pressure valves for limiting the internal pressure can also be included in the housing. The housing material and the housing shape must be optimized for decontamination.
It follows from the description and explanation and the above-indicated basic advantages of the pyrotechnic protection arrangement and protection surface according to the invention that it not only has technical power and efficiency values which hitherto were not even approximately achieved but it can also be designed within very wide limits. This therefore affords a virtually unlimited width of application and modularity.
In regard to armored vehicles this extends from panoramic protection including movable or fixedly mounted skirts to roof protection. Likewise it is possible to envisage protection for bottom surfaces in relation to corresponding threats. In addition pyrotechnic protection surfaces also represent very highly effective protection for containers or building structures.
While the present invention has been comprehensively described hereinbefore by means of various possible design configurations, it will be still self-evident to the man skilled in the art that numerous alterations and modifications can also be made therein without thereby departing from the scope of protection defined by the claims.

Claims (12)

1. A reactive protection arrangement without fragment formation being relevant in terms of terminal ballistics in both operational directions for an object to be protected, wherein two pyrotechnic layers which are inclined in the region of action of the threat are arranged at a spacing from each other and are arranged on both sides on a rigid or flexible, single-layer or multi-layer carrier being inclined in the region of action of the threat and being formed of at least one metallic or non-metallic materials of very low density of less than about 30 kg/m3, such that after firing of the two pyrotechnic layers shock waves and reaction gases are formed and are accelerated at an angle both in opposite relationship to and also in the direction of the penetrating threat in such a way that the pyrotechnic protection surface made of the two pyrotechnic layers and the carrier is disposed almost over the entire period of action in a condition of dynamic equilibrium.

2. A reactive protection arrangement as set forth in claim 1, wherein at least one of the pyrotechnic layers has a free surface or is only slightly tamped at one or both sides only in the order of 0.1 mm thickness.

3. A reactive protection arrangement as set forth in claim 1 or 2, wherein the carrier is a casing which is entirely or partially filled with a low density material.

4. A reactive protection arrangement as set forth in any one of claims 1 to 3, wherein the two pyrotechnic layers are arranged in parallel relationship or at an angle relative to each other on the object to be protected.

5. A reactive protection arrangement as set forth in any one of claims 1 to 4, wherein the pyrotechnic protection surface made of the two pyrotechnic layers and the carrier is arranged in fixed, movable or releasable relationship.

6. A reactive protection arrangement as set forth in any one of claims 1 to 5, wherein the pyrotechnic protection surface made of the two pyrotechnic layers and the carrier is arranged in a housing made of a metallic or non-metallic material.

7. A reactive protection arrangement as set forth in claim 6, wherein there are arranged chambers which are separated from each other and which are empty or are filled with substances not forming fragments in the housing.

8. A reactive protection arrangement as set forth in claim 7, wherein the chambers are filled with filling substances which break up and which do not form effective fragments.

9. A reactive protection arrangement as set forth in any one of claims 1 to 8, wherein the two pyrotechnic layers comprise a front pyrotechnic layer and a rear pyrotechnic layer in the direction of the penetrating threat, wherein the rear pyrotechnic layer is backed by a buckling arrangement directly or at a spacing.

10. A reactive protection arrangement as set forth in any one of claims 1 to 9, wherein the pyrotechnic protection surface made of the two pyrotechnic layers and the carrier is integrated into an active armouring arrangement.

11. A reactive protection arrangement as set forth in any one of claims 1 to 10, wherein at least one of the pyrotechnic layers is arranged between two layers carrying the same.

12. A reactive protection arrangement as set forth in any one of claims 1, 2 and 3 to 11, wherein the carrier is a metallic or non-metallic intermediate layer of foil thickness.