CN211346577U - An active shock wave and fragmentation protection system with interlayer synergistic gain - Google Patents

Abstract

The utility model provides an active shock wave and fragment protection system of gain in coordination between layers has utilized the initiative protection concept of pre-acceleration, has realized the gain effect in coordination between the protective layer, can improve the shock wave and the fragment efficiency of two inoxidizing coatings simultaneously. The method specifically comprises the following steps: the method comprises the following steps that an explosive-faced surface weakens an incoming explosive shock wave through a shock wave protective layer, and a back explosive surface captures an incoming fragment through a fragment protective layer based on high-performance fibers; and before the explosive load reaches the shock wave protective layer, the shock wave protective layer and the fragment protective layer are pre-accelerated respectively, so that the shock wave protective layer has an initial speed opposite to the direction of the incoming explosive load, and the fragment protective layer has an initial speed the same as the direction of the incoming explosive load.

Description

An active shock wave and fragmentation protection system with interlayer synergistic gain

technical field

The utility model relates to a shock wave and fragment protection system, in particular to an active shock wave and fragment protection system with interlayer synergistic gain, belonging to the technical field of public safety protection.

Background technique

The shock wave and fragment load generated during the explosion of military or homemade improvised explosive devices often cause great harm to personnel, equipment and facilities in the surrounding environment; the design of explosion protection structures has always been the focus and focus of research at home and abroad. In order to reduce the secondary damage of fragment load, more and more research attention has been shifted from traditional high-strength materials to structurally fragile materials, such as fine sand, liquid, non-metallic porous materials (polyurethane foam), and non-metallic granular materials. (perlite), high-performance fiber cloth, etc. Because most of these materials have the characteristics of low density and low structural strength (multi-finger shearing, compressive or tensile breaking strength is very low, and easy to break), and they are easily broken into small particles (fragments) under the action of explosion loads, which are not suitable for Fragments that can cause secondary damage will be generated, so the explosion-proof structure based on structurally fragile materials has the advantages of light weight and higher safety.

How to combine different kinds of structurally fragile materials to improve the impact protection efficiency of explosion-proof structures is the focus of current research.

Utility model content

In view of this, the present invention provides an active shock wave and fragmentation protection system with interlayer synergistic gain, which utilizes the concept of pre-acceleration active protection, realizes the synergistic gain effect between layers, and can simultaneously improve the shock wave and fragmentation of two layers of materials. Fragment protection efficiency.

The active shock wave and fragment protection system with interlayer synergy gain includes: a shock wave protection layer, a fragment protection layer, and a pre-acceleration layer disposed between the shock wave protection layer and the fragment protection layer; the fragment protection layer is based on high performance The protective layer of the fiber, the shock wave protective layer adopts a flexible protective material; when in use, the shock wave protective layer is used as the blast surface;

An excitation device is arranged inside the pre-acceleration layer, and the excitation device is electrically connected to a front-end trigger sensor arranged between the explosive and the protection system; when the front-end trigger sensor senses an explosion load, the pre-acceleration layer is sent to the pre-acceleration layer. The internal excitation device sends an excitation signal, the excitation device drives the pre-acceleration layer, and after the pre-acceleration layer is activated, it performs work on the shock wave protection layer and the fragment protection layer, so that the shock wave protection layer has the same load as the incoming explosion. The initial velocity in the opposite direction makes the fragment protection layer have the same initial velocity as the direction of the incoming explosion load;

The setting position of the front-end trigger sensor should ensure that the pre-acceleration layer is activated within the set time before the explosive load reaches the protection system.

As a preferred mode of the present invention, the excitation device includes two or more driving points arranged in the same plane inside the pre-acceleration layer. After the excitation device receives the excitation signal from the front-end trigger sensor, all The driving point simultaneously activates driving the pre-acceleration layer.

As a preferred mode of the present invention, the pre-acceleration layer is provided with a gunpowder propellant, and the excitation device is an igniter of the gunpowder propellant.

beneficial effect

(1) The active shock wave and fragment protection system with interlayer synergistic gain proposed by the present utility model considers shock wave and fragment load at the same time, and considers the difference in shock wave/fragment protection mechanism of different types of structurally fragile materials, using pre-accelerated The concept of active protection realizes the synergistic gain effect between layers, which can improve the shock wave and fragment protection efficiency of the two layers of materials at the same time.

(2) The entire protection system of the present utility model contains three layers, wherein the pre-acceleration layer converts its own chemical energy or potential energy into the momentum of the other two layers; since the pre-acceleration layer is located in the middle, the B-type material protection layer and The momentums obtained by the P-type material protective layers at the rear end are opposite, and their respective momentums have a promoting effect on their respective protective performance. And because the pre-acceleration layer is in the middle, the momentum of the entire protection system is conserved after energy conversion, so the momentum balance on both sides can be achieved, the introduction of secondary momentum into the environment can be effectively avoided, and it has a more reasonable practical use.

Description of drawings

Fig. 1 is the shock wave and fragmentation protection system configuration diagram of the utility model;

FIG. 2 is a schematic diagram of the relative reverse acceleration of the protective layers on both sides under the work of the pre-acceleration layer after the pre-acceleration layer is excited.

Among them: 1-B type material protection layer, 2-Pre-acceleration layer, 3-P type material protection layer, 4-Excitation device, 5-Front trigger sensor, 6-Incoming explosion load

Detailed ways

The specific implementations of the present utility model will be described in further detail below with reference to the embodiments of the utility model. The following structural examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

This embodiment provides an active shock wave and fragmentation system with interlayer synergy gain. Considering the differences in shock wave/fragment protection mechanisms of different types of structurally fragile materials, the pre-acceleration active protection concept is used to realize the synergy between the two protective layers The gain effect can improve the shock wave and fragment protection efficiency of the two layers of materials at the same time.

The active protective structure with synergistic gain between layers should be able to simultaneously weaken the explosion shock wave and greatly reduce the fragmentation velocity. Therefore, the structurally fragile materials used can be divided into two categories according to their uses: one is the typical fragmentation protection material (called P-type material) , such as various high-performance fiber cloths, the main protection mechanism is the fracture of high-strength materials; the other type is typical shock wave protection materials (called B-type materials), such as fine sand, liquid, non-metallic porous materials (polyurethane foam These materials have good shock wave load weakening performance, and an important point in their shock wave protection mechanism is the momentum extraction effect, which can also reduce the fragment movement speed through the momentum extraction effect.

For P-type materials, high-strength material fractures are divided into direct tension, out-of-plane shear, and indirect tension. These failures all depend on the stress (pressure) level S formed by the fragment in the material. For a stationary target plate, S basically depends on the impact velocity V _i of the projectile, namely: S∝V _i ; the study found that if the fragment hits the P-type material target plate, the material is pre-accelerated (even if it obtains an initial velocity) V _p , the direction of which is the same as V _i ), will increase the _Vi required for the material to fracture, the reason is: fundamentally S depends on the relative speed of the fragment and the target plate, namely: S∝V _i -V _p ; Therefore, the existence of V _p makes S smaller under the condition of the same target hitting speed V _i , so that the material P is more difficult to break, so that the anti-elastic performance of the target plate is improved.

For Class B materials, the dominant protection mechanism of shock waves and fragments is the momentum extraction effect; the target plate of Class B materials will obtain a maximum average velocity V _bc after the shock wave protection, and a local maximum speed V bc will be obtained after a certain fragment protection Velocity V _bp . For a stationary target plate, the shock wave reduction rate C _r and the fragment velocity drop rate P _r caused by the momentum extraction effect depend on the mass m _b of the target plate, that is, the greater the quality of the target plate of type B material, the better the protection effect . For some B-type materials that can absorb energy through their own plastic deformation, such as polyurethane foam, the additional shock wave reduction rate caused by them also depends on the mass m _b of the B-type material target plate. Therefore, in order to make the B-type material have a good protective effect, the weight m _b of the target plate needs to be large enough.

If the B-type material target plate is pre-accelerated before the shock wave and fragment load strikes (even if it obtains an initial velocity V _b0 , the direction of which is opposite to the direction of the incoming shock wave and fragment velocity). When the shock wave hits, the relative velocity between the incoming shock wave and the B-type material target plate becomes larger. It is assumed that after the shock wave is over, the B-type material target plate as a whole still obtains a maximum average speed V _bc , obviously this process is compared to the static state. In this case, more shock wave energy will be dissipated, that is, C _r will increase. Similarly, when the fragment strikes, the relative velocity between the fragment and the B-type material target plate becomes larger. Research shows that the kinetic energy of the fragment dissipated by the B-type material target plate with a fixed areal density increases with the distance between the fragment and the B-type material target plate. increases with the increase in relative speed. The reason is that the drag resistance of the fragments in the B-type material target plate increases, so the energy dissipation efficiency of the B-type material target plate is improved, that is, the rate of reduction of the fragment velocity P _r increases. To sum up, if the target plate of class B material can be reversely pre-accelerated before the shock wave and fragments strike, the protection efficiency of the shock wave and fragments can be improved.

Aiming at the analysis of the protection characteristics of the above P-type materials and B-type materials, an active shock wave and fragment protection method based on synergistic gain is proposed.

As shown in Figure 1, a B-type material protective layer 1 is set on the explosive surface (ie, the direction of the explosion load), a P-type material protective layer 3 is set on the back explosion side, and the B-type material protective layer 1 and the P-type material protection layer are provided. A pre-acceleration layer 2 is set between layers 3; in this example, the protective material in the protective layer 1 of the B-type material is pure water, and the protective material in the P-type material protective layer 3 is ultra-high molecular weight polyethylene fiberboard, both of which are structurally fragile materials , the weight ratio of the two is 5:1. A pre-acceleration layer 2 based on the gunpowder propellant is sandwiched between the B-type material protective layer 1 and the P-type material protective layer 3. The pre-acceleration layer 2 restricts the work direction of the gunpowder propellant to the direction of the protective layer through a plurality of independent nozzles. The normal direction (that is, the ejection direction of the nozzle is along the normal direction of the protective layer). When the fragment protection layer 3 is a structurally fragile material that is not resistant to high temperature, the end face of the fragment protection layer 3 facing the pre-acceleration layer 2 side is bonded with a heat-insulating (fireproof) material, such as fireproof cotton, to avoid the damage caused by the gunpowder. High-performance fabrics appear to melt or burn. An excitation device 4 is arranged at the center of the pre-acceleration layer 2 , and the excitation device 4 is an igniter of a gunpowder propellant. The excitation device 4 is connected by a cable to the front-end trigger sensor 5 near the position of the incoming explosive load 6 .

When the pre-acceleration layer 2 is not considered, the function of the B-type material protective layer 1 is to weaken the incoming explosion shock wave and reduce the speed of the fragments to a certain extent, while the function of the P-type material protective layer 3 completely captures the incoming fragments. . When considering the pre-acceleration layer 2, with the front-end trigger sensor 5, when the explosive explodes, when the fastest part of the explosive load (shock wave and fragment) reaches the position of the front-end trigger sensor 5, the front-end trigger sensor 5 is triggered, and the front-end trigger sensor 5 is triggered. The sensor 5 immediately transmits the ignition signal to the excitation device 4 inside the pre-acceleration layer 2 through the cable, so that the pre-acceleration layer 2 can be excited before the explosion shock wave and the fragmentation load arrive. The setting position of the front-end trigger sensor 5 should ensure that the explosion load reaches the protective structure. In the previous set time (usually several ms), the pre-acceleration layer 2 uses the form of gunpowder to ignite to do work on the B-type material protective layer 1 and the P-type material protective layer 3 on both sides, so as to protect the B-type material. The layer 1 is pre-accelerated in the reverse direction, and the P-type material protective layer 3 is positively pre-accelerated, so that when the explosion load reaches the protective structure, the B-type material protective layer 1 has an initial velocity V _b opposite to the incoming explosion load 6 , while P The material-like protective layer 3 has a muzzle velocity V _p opposite to the direction of the incoming blast load 6 , as shown in FIG. 2 . Based on the protective properties of the above P-type materials and B-type materials, the pre-acceleration of the B-type material protective layer 1 and the P-type material protective layer 3 caused by the pre-acceleration layer 2 is beneficial to the improvement of their respective shock wave and/or fragment protection efficiency.

From a practical point of view, the acceleration process of the pre-acceleration layer 2 should match the time advance of the front-end trigger sensor 5, that is, the time interval between the action time of the pre-acceleration layer 2 and the explosion load reaching the protective structure should be at the ms level; The initial velocity V _p of the material protective layer 3 can reach the level of 100 m/s, and the initial velocity V _b of the B-type material protective layer 1 can reach the level of 50 m/s. In order to achieve this function, the interior of the pre-acceleration layer 2 uses gunpowder propellant ignition or low-equivalent low-speed explosive explosion. These explosives are more efficient than mechanical structures such as springs, but they will not be protected by P-type materials. Higher stress is generated in layer 3 and B-type material protective layer 1 (mainly, stress accumulation will not occur in P-type material protective layer 3 layer, or the transient pressure is not enough to cause P-type material protective layer 3 to occur in advance. damage). After pre-acceleration, the pre-acceleration layer 2 self-destructs and disappears, and the B-type material protective layer 1 and P-type material protective layer 3 are accelerated. Since the driving time is at the ms level, the driving overload is low. As long as the driving load maintains a good plane uniformity, the The two protective layers will maintain good structural integrity. And for the P-type material protective layer 3, due to its high axial tensile strength (such as fiber composite materials), it is suitable for the low overload condition of gunpowder driving. Even if the flatness of the pre-driven load is poor, its own structure can propagate transverse shear waves, and it is difficult for fiber breakage to occur, and good structural integrity can be maintained. For the protective layer 1 of type B material, the following two methods can be used to ensure that the intermediate pre-acceleration layer 2 does not affect its structural integrity; a. Ensure that the driving load maintains a good plane uniformity (specifically, the excitation of the pre-acceleration layer 2 can be used. In the plane where the device 4 is located, multiple driving points are evenly spaced and ignited at the same time); b. On the side of the B-type material protective layer 1 facing the pre-acceleration layer 2, spray a superelastic layer such as polyurea to suppress the driving load in the plane Fractures caused by unevenness, ensuring structural integrity.

Since the protection mechanism of Class B material protective layer 1 against explosion shock waves and fragments is momentum extraction, the initial velocity V _b of Class B material protective layer 1 improves the protection efficiency against explosion shock waves and fragments; The fragment protection mechanism of layer 3 (UHMWPE fiberboard) is that the stress in the fiber reaches its own strength and breaks. Therefore, the initial velocity V _p of the P-type material protective layer 3 can reduce the contact between the incoming fragments and the P-type material protective layer 3. The speed difference between the two reduces the contact pressure (stress magnitude) formed in the P-type material protective layer 3 when the fragments impact, thereby improving the fragment protection efficiency of the P-type material protective layer 3 .

In addition, since the B-type material protective layer 1 and the P-type material protective layer 3 are located on both sides of the pre-acceleration layer 2, that is, during the pre-acceleration process, the reaction force of the gunpowder propellant to the work force of the B-type material protective layer 1 is It is the force that does work on the protective layer 3 of the P-type material, and vice versa. Therefore, the protective layers on both sides are in a state of synergistic gain, and the momentum of the protective system can be self-balanced, which greatly reduces the additional momentum damage to the surrounding environment.

In conclusion, the above are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (7)

1. An active shock wave and fragment protection system with synergistic interlamination, comprising: the device comprises a shock wave protective layer, a fragment protective layer and a pre-acceleration layer arranged between the shock wave protective layer and the fragment protective layer; the fragment protective layer is a protective layer based on high-performance fibers, and the shock wave protective layer is made of flexible protective materials; when the shock wave protection layer is used, the shock wave protection layer is used as a detonation facing surface;

an excitation device is arranged in the pre-acceleration layer and is electrically connected with a front-end trigger sensor arranged between the explosive and the protection system; when the front-end trigger sensor senses an explosive load, an excitation signal is sent to an excitation device in the pre-acceleration layer, the excitation device drives the pre-acceleration layer, the pre-acceleration layer does work on the shock wave protection layer and the fragment protection layer after being started, so that the shock wave protection layer has an initial speed opposite to the direction of the incoming explosive load, and the fragment protection layer has an initial speed the same as the direction of the incoming explosive load;

the front-end trigger sensor is arranged at a position which ensures that the pre-acceleration layer is started within a set time before the explosive load reaches the protection system.

2. The active blast and fragment protection system of claim 1, wherein said excitation means comprises two or more driving points disposed in the same plane within said pre-acceleration layer, and wherein upon receiving an excitation signal from said front-end trigger sensor, all of said driving points are simultaneously activated to drive said pre-acceleration layer.

3. An active shock wave and fragment protection system with synergistic interlaminar performance as claimed in claim 1 or claim 2 wherein said pre-acceleration layer is provided with a propellant powder and said excitation means is the igniter of the propellant powder.

4. An active shock wave and fragment protection system with synergistic interlayer gain as claimed in claim 3, wherein more than two independent nozzles are provided in said pre-acceleration layer, so that the working direction of said propellant powder is along the normal direction of said shock wave protection layer and said fragment protection layer.

5. An active shock wave and fragment protection system with synergistic interlayer gain as claimed in claim 1 or claim 2 wherein a superelastic layer is provided on the end face of the shock wave protection layer facing the pre-acceleration layer.

6. The interlaminar cooperative enhanced active blast and fragment protection system of claim 1, wherein a fire barrier is provided on an end surface of said fragment protection layer on a side facing the pre-acceleration layer.

7. The interlayer cooperative gain active blast and fragmentation protection system of claim 1, wherein the protection material in said blast protection layer is explosion-proof liquid or fine sand or non-metallic porous material or non-metallic lattice material or non-metallic granular material, and the material of said fragmentation protection layer is high performance fiber fabric.

Images