RU2094740C1 - Device measuring velocity of hitting element - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: proposed device measuring velocity of hitting element can find use at test ranges, experimental sites, in research establishments to measure velocity of hitting elements such as bullets, projectiles, fragments after their piercing through obstacles. Device includes transducer manufactured in the form of gauze electrode and is fitted with sensor of initiation, former of initiation pulse, time interval meter, coincidence circuit and former of stopping pulse. EFFECT: enhanced measurement accuracy and authenticity. 2 cl, 3 dwg

Description

 The invention relates to a control and measuring technique, and more specifically, to systems for indicating and registering the parameters of the striking elements and can be used at training grounds, experimental sites, in research institutions for measuring the speed beyond the striking elements (bullets, shells, fragments) when breaking through barriers.

 Known devices for recording the speed of the striking elements [1] containing a solid target, a unit for recording and processing information. The sensitive element of the launch unit is a punched target placed in front of a solid target. The disadvantage of this device is the inability to determine the exact value of the blocking speed, since the penetration of a barrier by a striking element is accompanied by the release of a large amount of energy due to its inhibition in the barrier. The release of energy leads to the destruction of the barrier, the formation of a "sheaf" of secondary fragments and the appearance in the region of penetration of a shock wave. These secondary factors lead to premature triggering of the recording equipment.

 A device [2] containing a sensor in the form of grid electrodes, insulated by a gasket, and a sensor signal processing unit is known. The design of the sensor in the form of two parallel grid electrodes provides reliable registration of penetration of the target by the projectile. The disadvantage of this solution is the inability to determine the blocking speed of the striking element.

 Thus, the known devices do not allow the measurement of the speed beyond the striking element.

 The proposed technical solution allows to determine the straddle speed of the striking element. Obtaining a new technical result is achieved by the fact that in the device containing the sensor, made in the form of grid electrodes, a start sensor, a start pulse shaper, a time interval meter, a coincidence circuit, a stop pulse shapers are additionally introduced, while the start sensor is connected in series with the start pulse shaper , with the start-up input of the time interval meter, and its stop input is connected in series with the output of the match circuit, and the inputs of the match circuit are black of pulse shapers are connected to the outputs of stop sensor, and a stop sensor are placed in parallel at least two pairs of grid electrodes, each electrode cell units are mounted opposite geometric center electrode previous cells.

 In FIG. 1 shows a diagram of a device for measuring backward speed; in FIG. 2 layout of the grid electrodes of the stop sensor; in FIG. 3 diagram of the activation of the grid electrodes of the stop sensor.

 In FIG. 1 shows a diagram of a device for measuring the outward speed, on which are indicated: a start sensor 1, a start pulse shaper 2, a time interval meter 3, a match circuit 4, a stop pulse shapers 5, a stop sensor 6, grid electrodes 7, an obstacle 8, the main damaging element 9 , secondary damaging elements 10, thermal decomposition products 11.

 The principle of operation of the proposed technical solution is based on the following physical phenomena of the interaction of the striking element with the barrier material. When a striking element penetrates an obstacle, a large amount of energy is released behind the barrier, depending on various factors (speed of the striking element, penetration mechanics, composition of the barrier material and the striking element), in addition to the main striking element, secondary striking elements are formed: a "sheaf" of fragments (from metal dust to larger fragments), the flow of thermal decomposition products of barrier materials and shock wave.

 After breaking through the barrier, the behavior of the secondary products is entirely determined by the amount of energy released. The shock wave attenuates sharply with distance from the penetration crater. Secondary fragments, as well as thermal decomposition products, are decelerated in the after-space, and the braking speed of the secondary fragments depends on their mass. Part of the secondary fragments, as well as thermal decomposition products, can have a speed higher than the stopping speed of the damaging element.

 The start sensor 1 is located directly behind the target, therefore, it can work (electrically close) from secondary influences, but since the secondary products will be in the acceleration stage, the difference from the sensor’s triggering from secondary products and from the damaging element will be insignificant and will amount to millionths seconds, which practically does not affect the estimate of the blocking speed. After breaking through the obstacle, the speed of the main striking element drops due to friction against the air, therefore, to accurately measure the stop speed, the stop sensor must be installed as close to the obstacle as possible, but the sensor falls into the zone of secondary products that could cause it to malfunction. To eliminate premature operation is a stop sensor 6 of a special design. By the difference in the time of arrival of the electric pulse at the starting input of the time interval meter and the electric pulse at its stopping input, as well as by the distance between the sensors 1 and 6, the stop speed of the striking element is determined.

 The main damaging element that has broken through the barrier, as well as the released secondary fragments, thermal decomposition products and the shock wave, will lead to an electrical short circuit of the start sensor.

 The stop sensor will first be exposed to secondary damaging elements. 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 striking element emerging from the barrier, the distance between the electrodes is selected from the condition of reliable closure of two adjacent electrodes by the striking element. 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 (Fig. 2). This design of the sensor allows to avoid premature operation of the sensor when exposed to fragments and to prevent its premature destruction from the effects of the shock wave and thermal decomposition products. To prevent shorting the sensor through the ionized thermal decomposition products, the electrodes can be made of insulated wires. The material for the manufacture of the trigger sensor can serve as a thin foil, and the grid electrodes of the trigger sensor can be made of thin insulated metal wire. The device operates as follows. The striking element 9 breaks through the barrier 8, forms the secondary striking elements 10, which act on the trigger sensor 1. As a result of the closure of the sensor 1, the pulse shaper 2 generates a signal that includes a time interval meter 3, then the striking element 9, the secondary striking elements 10 act on the sensor stops 6, the sensor design in the form of at least two pairs of parallel grid electrodes will allow thermal products of 11 to pass through, a shock wave and secondary fragments 10. Secondary e fragments 10, reaching the sensor 6 before the damaging element 9, will not be able to trigger it due to its smaller size (relative to element 9) and the grid structure of the sensor 6 (Fig. 3). After the damaging element 9 of each pair of grid electrodes 7 of the sensor 6 is closed, the electric signal is converted by the corresponding stop pulse shapers 5 and fed to coincidence circuit 4, the electric signal from which is fed to the stop input of the time interval meter 3 to stop measuring the time interval only when electrical signals arrive from each pair of grid electrodes 7 of the sensor 6. The stop sensor 6 may contain from two or more pairs of parallel grid electrodes 6 (FIG. 1), while coincidence circuit 3 gives a stop signal when the pairs of electrodes are sequentially closed.

 When exposed to the sensor 6 products 11, the design of the electrodes from insulated wires will eliminate their short circuit through the ionized products of thermal decomposition 11.

 The proposed device has high reliability of measuring the straddle speed of the striking elements, due to the design of the stop sensor.

 The device’s description does not include the geometrical sizes of the cells of the grid electrodes 7, the distances between the grid electrodes 7, the distances between the start sensors 1 and stop 6. Due to the wide variety of damaging elements, the ambiguous change in their geometric characteristics when breaking through various obstacles, and the strong dependence of the intensity of the formation of secondary fragments 10 and thermal decomposition products 11 from the entry speed of the striking element 9 into the barrier 8 and from the type of material of the barrier 8, the specific dimensions of the element These devices and the composition of the materials of elements 1 and 7 are determined experimentally.

 The device allows you to determine the staggered speed of the striking elements in the immediate vicinity of the hedge, both when testing special materials, and when testing specific technical devices, by placing sensors inside the latter.

 In the proposed device, grid sensors can be used as a stop sensor, each of which is made of two rows of parallel copper wires with a mesh size of 5 mm (the diameter of the damaging element emerging from the obstacle) and a distance between the grids of 2 mm.

 The coincidence and pulse formation scheme was performed on widely used 555 series microcircuits; the ChZ-34 frequency meter was used as a time interval meter.

 The layout of the device was tested during various experiments that showed its performance.

Claims (3)

 1. The device for measuring the speed of the striking element, including a stop sensor made in the form of grid electrodes, characterized in that it also includes a start sensor, a start pulse shaper, stop pulse shapers, a matching circuit, a time interval meter, and a start sensor through a shaper the start pulse is connected to the start input of the time interval meter, and its stop input is connected in series with the output of the match circuit, the inputs of the match circuit h Res stop pulse shapers are connected to the outputs of stop sensor, and a stop sensor are placed in parallel at least two pairs of grid electrodes, each electrode cell units are mounted opposite geometric center electrode previous cells.  2. The device according to claim 1, characterized in that the grid electrodes are made of insulated wires.  3. The device according to claim 1, characterized in that the trigger sensor is mounted on an obstacle in the exit zone of the striking element.

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