RU2465539C2 - Contact sensor for registration of damage agent approach moment during fragmentation shell explosion - Google Patents

Abstract

FIELD: weapons and ammunition.

SUBSTANCE: contact sensor for registration of a moment of damage agent approach during explosion of a fragmentation weapon, comprising a substrate from a non-conducting material, on the surface of which a system is placed from two conductors isolated from each other and connected to output terminals of a DC voltage source and closed on top by a protective layer, in it the system of isolated conductors is arranged in the form of a flat spiral from two metal strips, width of which makes a value of (3…6)·V·10^-6, [m], where V, [m/s] - expected speed of damage agent approach towards a sensor, besides, the width of insulating layer between conductors makes not more than 0.3 from the fragmentation weapon body thickness.

EFFECT: higher security of a contact sensor for definition of initial speed of damage agents throwout.

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Description

Technical field

The invention relates to the field of explosive ballistics. The technical result is the creation of a simple and reliable contact sensor to determine the initial expansion speed of the striking elements (PE).

State of the art

The invention relates to technical devices, which serve to determine the speed at the initial stage of the expansion of finished PE and fragments of natural crushing formed during the explosive destruction of shells of fragmentation ammunition (BP).

In [1], a method for testing fragmentation PSUs is presented, which is a modification of the well-known (guest) method for conducting fragmentation tests at test sites. Both methods are based on the following.

The velocity measurement here is usually combined with the determination of the distribution of fragments along the meridional angle of expansion. Use a semi-cylindrical vertical wall upholstered with a metal (duralumin or steel) sheet. BP is installed in the center of the half-cylinder in a horizontal position. With the help of high-speed movie cameras, the time t is recorded between two moments - the illumination of the shield when the shell is detonated and the moment the fragments hit the shield, which is recorded by the flashes upon impact. The speed of the fragments is defined as V ₀ = R / t, where R is the radius of the half-cylinder (the radius of the shell of the shell is considered negligible).

As a drawback of both methods, it can be noted that, since the distance R to the vertical wall is chosen sufficiently large (so that flying products of the explosion (PV) do not reach it and do not screen the shots of flashes from fragments), the velocity V ₀ calculated by the formula is average for the basis of the measurement of R, and it can be considered its initial velocity of the expansion of fragments only approximately. Indeed, in the process of expansion and fragmentation of the fragmentation shell of the BP, the velocity increases by fragments from zero to maximum over a certain period of time (albeit small), and this maximum velocity does not coincide with the velocity V ₀ .

Thus, when using the known method of measuring the velocity of expansion, important information is lost associated with the dynamics of acceleration of the fragmentation shell at its initial stage of movement.

In [2], a technical solution is presented, which is a subsequent modification of the previous one, consisting in the fact that the vertical wall is made in the form of a flat rectangle with two parallel lines deposited on it, arranged vertically or horizontally and forming the boundaries of the measuring base, the projectile axis is parallel to the said lines, the measuring base is placed in the field of view of the high-frequency camera and the time of movement of the fragmentation front along the measuring base is measured.

This technical solution does not eliminate the above drawback and leads only to some clarification of the average velocity of the fragment.

In a close technical solution [3], selected as an analogue, a device is proposed for measuring the straddle velocity of PE (bullets, shells, fragments) when breaking through barriers. A device comprising a sensor made in the form of grid electrodes is equipped with a start sensor, a start pulse shaper, a time interval meter, a coincidence circuit, and a stop pulse shaper. Penetrating the barrier of the main PE, as well as the released secondary fragments, PV and shock wave (HC) will lead to an electrical short circuit of the start sensor.

The stop sensor will first be exposed to secondary PE. For reliable operation, the stop sensor is made in the form of two or more pairs of parallel grid electrodes. The cell size of each electrode is equal to the diameter of the PE emerging from the obstacle; the distance between the electrodes is selected from the condition of reliable closure of the PE of two adjacent electrodes. The cells of the grid electrodes are shifted relative to each other so that the nodes of the cells of one electrode are opposite the geometric center of the cells of the other electrode. This design of the sensor allows you to avoid premature operation of the sensor when exposed to fragments and to prevent its premature destruction from the effects of hydrocarbons and air. To prevent shorting the sensor through ionized PV electrodes, they can be made of insulated wires. The material for manufacturing the trigger sensor can be thin foil, and the grid electrodes of the trigger sensor can be made of thin insulated metal wire.

The advantage of the device from [3] should be considered the representation of the contact sensor in the form of two or more pairs of parallel grid electrodes. However, the direct use of the proposed device for measuring the velocity of fragments during the explosion of a fragmentation PSU is problematic due to the fact that in this case, a strong shock wave moves first, then high-speed airplanes, and only then fragments of the hull that fly separated in the airplanes. Therefore, on the mesh electrodes, which should be located near the power supply unit, a sequential force action is carried out from the HC, PV and only then fragments. Since HC and PV near the triggered fragmentation PSU have very high parameters, they can lead to the destruction of the contact sensor even before the arrival of PE (fragments).

Therefore, a special design of the contact sensor is necessary, taking into account the features of its explosive loading.

In [4], a technical device was proposed that is closest in design to the proposed invention, therefore, it was chosen as a prototype. The device contains a substrate of non-conductive material, on the surface of which there is a system of two conductors isolated from each other, connected to the output terminals of a constant voltage source and covered with a protective layer on top.

The disadvantage is the same - the inability to use in explosive loading.

Disclosure of invention

The object of the present invention is to increase the security of the design of the contact sensor in relation to the conditions of the explosion.

This problem is solved by the fact that in a known technical device containing a substrate of non-conductive material, on the surface of which there is a system of two conductors isolated from each other, connected to the output terminals of a DC voltage source and covered with a protective layer on top, the system of insulated conductors is made in it a flat spiral of two metal strips, the width of which amounts to (3 ... 6 · V · 10 ^-6 [m], where V, [m / s] - the expected rate of approach of the projectile to the sensor, wherein Irina insulating layer between the conductors is not more than 0.3 times the thickness of the body shrapnel munition.

List of drawings

Figure 1. Layout of sensors near the fragmentation PSU;

Figure 2. Type of sensor and its cross section;

Figure 3. Practical implementation of the invention in a landfill;

Figure 4. Typical registration.

The implementation of the invention

In the drawings, numbers and letters denote:

1 - fragmentation BP;

2 - contact sensor;

3 - non-conductive substrate;

4 - bare conductor;

5 - an insulating layer;

6 - an emphasis for placement of the contact sensor;

7 - a protective layer;

x _i - removal of sensors to the surface of the PSU.

Figure 1 shows the layout of the sensors at different distances x _i from the surface of the PSU, while the sensors 2 are placed at an increasing distance from the surface of the PSU 1 with an offset in the angle to prevent screening each other.

Figure 2 shows the view of the sensor and its central section. A system of two conductors 4 made of a thin metal strip, together with an insulating layer 5 between them, is placed on the surface of a non-conductive substrate 3 in the form of a flat spiral, while the ends of the conductors are connected to different poles of a constant voltage source. From the side of the sensor facing the PSU, the conductors are covered with a protective layer 7 to prevent the sensor from triggering from ionized PV and HC, and the protective layer 7 is made of low-density insulating material (adhesive tape, cardboard).

The bandwidth is selected from the conditions for ensuring the reliability of registration. The fact is that when recording parameters of an explosion by electric methods, oscilloscopes always detect electromagnetic interference. As the results of the experiments showed, the duration of the interference, as a rule, does not exceed 1.5 ... 3 μs from the moment the sensor starts to work. The useful signal varies quite confidently against the background of interference in the event that its duration is approximately twice the duration of the interference, i.e. will be equal to t = 3 ... 6 μs. Assuming that the PE velocity V varies insignificantly during this time, a simple relation follows for the bandwidth — a = V · t = (3 ... 6) · V · 10 ^-6 [m]. The expected PE velocity during the explosion of a fragmentation BP can be estimated from the known dependences [5].

The sensor is triggered when the electric circuit conductor - PE - conductor is closed directly through the PE, therefore, the step of winding the spiral h should be no more than the width of the PE. During the explosive expansion of the fragmentation shell of a BP, it is thinned and, at a thickness of 0.6δ, fragmentation occurs. For reliable registration, it was assumed that 2h≤0.6δ, whence h≤0.3δ.

Figure 3 presents a variant of the practical implementation of the invention in field conditions - the location of the sensors near the high-explosive fragmentation warhead.

Figure 4 shows a typical waveform recording the operation of the assembly of four sensors.

The proposed technical device operates as follows. The start of all sensors occurs at the same time, corresponding to the supply of an initiating pulse to the detonator capsule (indicated by a horizontal arrow for each sensor in Fig. 4. Then, the detonation wave propagates along the explosive charge, which corresponds to the horizontal “shelves” in FIG. 4. The moment of closure of the first sensor by the expanding shell located in this case directly on the surface of the PSU is marked with a vertical arrow. Further recording corresponds to electromagnetic interference on the rest sensors until fragments have yet reached them, and their sequential operation (moments of breakage of the recording). It can be seen that when conducting conductors in the form of strips, the resulting electromagnetic interference does not prevent the detection of the moment of operation of the sensors.

Thus, by recordings, it is possible to accurately track the moments of time t _{i of the} response of the sensors, by which the time of movement of the fragment between the sensors Δt _i = t _i -t _i-1 and taking into account the distance between them Δx _i = x _i -x _i-1 , we have V _i = Δх _i / Δt _i - the average flight speed of the fragment in the area Δх _i .

Information sources

1. Patent RU 2131583 dated 04/05/1996.

2. Patent RU 2353893 dated 09.03.2007.

3. Patent RU 2094740 dated 05.21.1996.

4. Impact dynamics: Trans. from English / Zukas J.A., Nicholas T., Swift H.F. et al. - M.: Mir. 1985.p.131, fig. 3.14.

5. Explosion Physics / Ed. L.P. Orlenko. - M .: FIZMATLIT. 2004.

Claims (1)

A contact sensor for detecting the moment of approach of the striking element during the explosion of fragmentation munition, containing a substrate of non-conductive material, on the surface of which there is a system of two conductors isolated from each other, connected to the output terminals of the DC voltage source and covered with a protective layer on top, characterized in that it a system of insulated conductors is made in the form of a flat spiral of two metal strips, the width of which is (3 ... 6) · V · 10 ^-6 , [m], where V, [m / s] is the expected the approach speed of the striking element to the sensor, while the width of the insulating layer between the conductors is not more than 0.3 of the thickness of the shell of the fragmentation munition.

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