RU2465538C2 - Contact sensor for registration of fragment approach moment during fragmentation shell explosion - Google Patents

Abstract

FIELD: weapons and ammunition.

SUBSTANCE: contact sensor for registration of a fragment approach moment during explosion of a fragmentation shell, comprising a metal substrate, a bared conductor and a thin layer of insulation material placed between the substrate and the conductor, which are connected with opposite terminals of a DC voltage source, besides, the surface of the bared conductor at the side facing the shell is coated with a protective layer from a low-density insulation material with the specific weight of 0.1…0.4 g/cm. The conductor itself is arranged in the form of a thin wire coil, the pitch between turns of which makes not more than 0.3δ, where δ - thickness of the fragmentation shell body.

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

4 dwg

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 velocity of the expansion of fragments.

State of the art

The invention relates to technical devices that serve to determine the speed at the initial stage of the expansion of finished striking elements (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. A semi-cylindrical vertical wall is used, 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 fixed 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 at the base measurements of R, and it can be considered as the 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 mentioned 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 sensor will first be exposed to secondary PE. For reliable operation, the 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 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 the manufacture of the trigger sensor can serve as a thin foil.

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 in the near explosion zone 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 body fragments 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 comprises a metal substrate, a bare conductor and a layer of insulating material placed between the substrate and the conductor, which are connected to the opposite terminals of the DC voltage source.

The disadvantage is the same - the impossibility of direct 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 metal substrate, a bare conductor and a layer of insulating material placed between the substrate and the conductor, which are connected to the opposite terminals of the DC voltage source, the surface of the exposed conductor from the side facing the projectile is covered with a protective layer of low-density insulating material having a specific weight of 0.1 ... 0.4 g / cm ^2, wherein the conductor is in the form of a thin wire snake, wherein the pitch between the turns of the composition yaet no more 0,3δ, where δ - thickness of the shell shrapnel shell.

List of drawings

Figure 1. Layout of sensors near a fragmentation shell.

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 - metal substrate;

4 - bare conductor;

5 - a protective layer;

6 - an emphasis for placement of the contact sensor;

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 projectile, 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. The bare conductor 4 is placed on the surface of the metal substrate with a layer of insulating material 3 in the form of a snake, while the ends of the snake are twisted into one wire and connected to one pole of a constant voltage source. A metal substrate 3 is connected to the second pole. From the sensor side facing the power supply, the wires are covered with a protective layer 5 to prevent the sensor from triggering from ionized PV and HC, and the protective layer 5 is made of low-density insulation material (adhesive tape, cardboard) with a specific gravity of 0, 1 ... 0.4 g / cm ² . As experiments show at a specific gravity of 0.1 g / cm ² , in the near explosion zone of a PS, the protective layer and a bare conductor are destroyed before the PE arrives, and at a specific mass of more than 0.4 g / cm ² , a noticeable decrease in the PE velocity occurs and appears instability of the sensor. The implementation of the bare conductor in the form of a snake allows you to minimize electromagnetic interference in the explosion on the recording equipment through a capacitor substrate - bare conductor. With a different form of execution of the exposed conductor (foil, frequent mesh, etc.), the arising pickups increase so much that they practically do not allow recording the moment of the sensor operation. The sensor is triggered when the exposed conductor - substrate is closed by the circuit directly through the splinter, so between snaps the pitch of the snake h should be no more than the width of the splinter. During explosive expansion of the fragmentation shell, its thinning occurs and at a thickness of the order of 0.6δ, it is destroyed into fragments. For reliable operation of the sensor, it was assumed that 2h≤0.6δ, which implies h≤0.3δ.

Figure 3 presents a variant of the practical implementation of the invention in field conditions - the location of the sensors near a high-explosive fragmentation projectile of 152 mm caliber.

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 figure 4). Then, the detonation wave propagates along the explosive charge, which corresponds to the horizontal "shelves" in figure 4. The moment of closure of the first sensor by the expanding shell located in this case directly on the surface of the projectile is indicated by a vertical arrow. Further recording corresponds to electromagnetic interference on the remaining sensors, while the fragments have not yet reached them, and their successive operation (moments of recording break). It is seen that when performing a bare conductor in the form of a snake, the resulting electromagnetic interference does not interfere with the registration 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 = Δx _i / Δt _i - the average flight speed of the fragment in the area Δx _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. Batuev G.S., Golubkov Yu.V., Efremov A.K., Fedosov A.A. Engineering methods for studying shock processes. - M.: Mechanical Engineering, 1977, p. 228, Fig. 130.

Claims (1)

A contact sensor for detecting the moment of arrival of a fragment during the explosion of a fragmentation projectile, containing a metal substrate, a bare conductor and a thin layer of insulating material placed between the substrate and the conductor, which are connected to the opposite terminals of the DC voltage source, characterized in that the exposed conductor surface is on the side facing to the projectile, is covered with a protective layer of low-density insulating material with a specific gravity of 0.1 ... 0.4 g / cm ² , while the conductor itself is made in the form of a snake from t thin wire, the step between the turns of which is not more than 0.3δ, where δ is the thickness of the shell of the fragmentation shell.

Images