RU2789676C1 - Method for assessing the damaging effect of high-explosive anti-personnel mines - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates to the field of mechanical engineering, and in particular to the field of testing engineering ammunition, in particular anti-personnel high-explosive mines (HEM) to assess the characteristics of high-explosive action. The method for assessing the destructive effect of the HEM, which includes placing the HEM and pressure sensors on the test site, detonating the HEM, recording the parameters of the air shock wave, differs in that the pressure sensors are placed on the test site at a given distance from the HEM, the explosion of the HEM is carried out in the ground with control measurement - a measuring complex of parameters of the air shock wave in the shock wave front, namely, the excess pressure in the shock wave front and the speed of the shock wave front, then determine the time of the compression phase of the shock wave front at a given point and the coordinate law of defeat in the form of the probability of defeating a conditional target from excessive pressure in the shock wave front or from the specific pressure impulse at different distances from the place of HEM rupture.

EFFECT: increasing the information content of tests, reducing the time, labor intensity and cost of testing by determining the indicators of the high-explosive action of the HEM at various distances from the mine rupture site with an assessment of the conditional probability of hitting a typical target.

1 cl, 2 tbl, 12 dwg

Description

The invention relates to the field of mechanical engineering, namely to the field of testing engineering ammunition, in particular anti-personnel high-explosive mines (PFM) to assess the characteristics of high-explosive action.

High-explosive is understood as such an action in which the target is hit by the products of an explosion of a bursting charge and an air shock wave (ASW).

During the explosion of a bursting charge of an explosive, its potential energy is converted into the kinetic energy of the highly heated gases formed. The gaseous products of the explosion due to the high rate of explosive transformation at the first moment practically occupy the volume of the charge itself and are in a highly compressed state. The pressure at the point of explosion of standard explosives reaches 4.5⋅10 Pa (450,000 kgf/cm ² ). Expanding, the products of the explosion hit the environment sharply.

The specificity of the installation of mines of this class lies in the installation in the ground with a masking layer of soil up to 5 cm thick, therefore, it is necessary to take into account the energy consumption of detonation products to overcome the resistance of the soil, which is determined experimentally.

There is a known method for assessing the characteristics of explosiveness during an explosion in the air of a moving test object (patent RU 2649999 C1, 06/04/2018), where the technical result is achieved by the possibility of determining the actual characteristics of explosiveness for ammunition with its own flight speed. The disadvantage of the above method is the sufficient complexity of preparing for the implementation of tests, insufficient information content associated with the impossibility of determining the direction and speed of the air shock wave at various distances from the mine rupture site, and not determining the time of the air shock compression phase at a given point.

There is a known method for determining explosive characteristics (patent RU 2522640 C2, 07/20/2014), where during testing, a test object is fired in the form of a fragment or a reduced model of ammunition from a ballistic installation, its charge is detonated at a given point of the trajectory, and the characteristics of the passing explosive are recorded. Using the similarity method and the obtained coefficients, the characteristics of the rupture of a real ammunition having its own speed and their distribution in an unlimited space are determined. The disadvantage of the above method is the sufficient complexity of preparing for the implementation of tests, not determining the time of the compression phase of the explosive at a given point, and estimating the parameters of the explosion of the ammunition only in the air.

There is a known method for determining the explosive action of the test object (patent RU 2519164 C1, 06/20/2014), in which an information sensor is installed at the test control point, having a geodetic reference to the spatial coordinate system of the test site, then a beacon is installed on the test object, signals from the information sensor are received from beacon of the test object and pressure gauges. After that, the received signals are processed, the spatial coordinates of the test object and pressure meters on the test site are determined, the coordinates of the test object and pressure meters are stored in the computer memory. The beacon is removed from the test object, the test object is detonated, the parameters and the average speed of the ASW are measured at each measuring point. The measurement results are processed and the parameters of the air shock wave are recorded at each measuring point in the computer memory block. Then a test document is generated in an automated mode.

The disadvantage of the above method is the sufficient complexity of preparing the implementation of the tests and not determining the time of the compression phase of the ASW at a given point, the estimation of the parameters of the explosion of the test object only in air.

A known method of influencing substances and objects with successive shock waves, designed for remote shock-wave effects on various substances and objects (patent RU 2335731 C2, 10.10.2008). The disadvantage of the above method is the sufficient complexity of preparing a multiple impact on various objects (from short series, on the order of 3-10 pulses, to continuous), arbitrary frequency (from infrasonic to ultrasonic) and arbitrary force (within the power of the emitter), insufficient information content associated with the impossibility of determining the direction and speed of the blast wave front at different distances from the place of the mine rupture, not determining the time of the compression phase of the blast wave at a given point, estimating the parameters of the explosion of the test object only in the air.

Closest to the invention is a method for determining the characteristics of explosive explosiveness of ammunition (patent RU 2593518 C1, 10.08.2016), including placement on the surface of the measuring site on the measuring beams, in given directions and at given distances from the point of detonation, pressure sensors, installing the test ammunition in a given point with subsequent detonation or its detonation at a given point in the process of moving with registration of the characteristics of the passing ASW at the measuring points. The disadvantage of the above method is the sufficient complexity of preparing the implementation of tests, insufficient information content associated with the impossibility of determining the direction and speed of the air shock wave front at different distances from the mine rupture site, not determining the time of the air shock compression phase at a given point, and estimating the parameters of the explosion of the test object only in the air.

The purpose of the tests in the proposed method is to determine the indicators of the high-explosive action of the PFM at different distances from the mine rupture site with an assessment of the conditional probability of hitting a typical target.

The technical problem to be solved by the claimed invention is to increase the information content of tests and the accuracy of determining the parameters of the air shock wave necessary to determine the probability of hitting a conditional target (open manpower) from overpressure (IP) in the shock wave front (SWF) or from a specific pressure impulse (UID) at various distances from the mine explosion, the completeness of processing the test results, as well as reducing the time, labor intensity and cost of testing.

The technical result, which can be obtained by solving a technical problem, is to increase the information content of tests to determine the probability of hitting a conditional target (open manpower) from ID in the HPF or from the specific pressure impulse (SPI) at various distances from the mine rupture site, which is achieved by measuring the parameters of explosiveness - ID and speed of the FCF, as well as by reducing the time, labor intensity and cost of testing through the use of empirical dependencies linking indicators characterizing the damaging effect of PFM with the values of its physical factors and the technical characteristics of the object under study.

The set task with the achievement of the technical result is achieved by the fact that in the proposed method for assessing the high-explosive PFM, two stages are implemented - the first, where pressure sensors are placed on the test site at a given distance and in directions and the PFM is detonated in the soil with the measurement of the parameters the speed of the HCF), and the second, consisting in determining the time of the compression phase of the HCF at a given point and the coordinate law of destruction in the form of the probability of hitting a conditional target (open manpower) from the ID in the HCF or from the HSM at various distances from the place of the mine rupture at the minimum required number tests.

At the first stage, a test site with a size of 10x10 m is used, lined with soil on three sides. On the test site, the test object (PFM sample) is placed in a hole with a soil thickness of up to 5 cm (Fig. 1). A control and measuring complex (CMC) based on a PC and a built-in high-frequency board (for example, type L-783 by L-Card) is placed to fix with a high degree of accuracy the moments of arrival of the FCF at given points in space. The electrical circuit of the CFC with parallel connection of 16 channels in the differential mode is shown in Fig. 2. For direct fixation of the moment of arrival of the HPF at given points in space, high-frequency membrane and ionization sensors are placed at a fixed distance from the PFM (l ₁ , l ₂ , ..., l ₆ ) (Fig. 3, 4). Steel plates 25 mm thick, 75 mm wide and 750 mm or 1000 mm long were used as a base for mounting both types of sensors. Options for installing sensors with holes through 75 mm and through 100 mm are shown, respectively, in Fig. 5, 6. The PFM is blasted in the soil with the measurement of the parameters of the air shock wave in the air shock wave (excessive pressure, the velocity of the shock wave front), the time of the compression phase of the air shock wave at given points is determined. For each sample of PFM and the adopted layout of high-frequency sensors, 3 experimental test explosions are carried out, the results of which are immediately processed by the CMC and displayed on the PC screen in the form of oscillograms, graphs and tables. Subsequently, they are statistically processed.

The error in measuring the distances from the center of the PFM sample to the nearest observation point is δ _r =1⋅10 ^-3 /0.2⋅100=0.5%, and to the farthest measurement point - δ _r =1⋅10 ^-3 /1 .6⋅100=0.0625%.

The error in measuring the time of arrival of the shock wave front to the nearest observation point is δ _t =3⋅10 ^-7 /2.5⋅10 ^-5 ⋅100=1.2%, and to the most remote point - δ _t =3⋅10 ^{- 7} /2.15⋅10 ^-4 ⋅100=0.14%.

Thus, the total maximum instrumental error in registering the moment of arrival of the shock wave front at the observation point closest to the charge can be _δtot = 0.5 + 1.2 = 1.7%, the total minimum error (for the most distant registration point) can be not more than δ _total =0.0625+0.14=0.205%, which ensures high measurement accuracy.

In all cases, when a PFM sample is exploded electrically (from an explosive machine or a recording device), a break in the main wire of the electrical explosive network is arranged at a safe distance from the PFM. The gap rises to a rail at least a meter high and is placed in a place that is clearly visible from the location of the charge. The safety gap is closed by the performer of explosive works (explosive worker) after the personnel involved in the experiment (explosive work) are withdrawn to the shelter and electric detonators (detonators) are placed in charges.

At the second stage, the time of the phase of compression of the HPF and the coordinate law of destruction (the probability of hitting a single target of the ID in the HPF or MP at a given distance from the point of detonation of the mine) of the object under study are determined, the dependencies connecting the indicators characterizing the damaging effect of the PFM with the values of its physical factors and technical characteristics of the object under study. In this case, the algorithm for calculating these indicators is as follows.

1) Determining the time of the compression phase

- эквивалент тротила;Where

- the equivalent of TNT;

Q _BB and Q _THT - specific heat of explosion of explosive (HE) and TNT (TNT) (see table 1).

2) If τ>1⋅10 ^-3 s, then the target is hit by the ID in the FUW, if τ≤1⋅10 ^-3 s, then the target is hit by the ID in the FUW.

3) The probability of hitting a target (open manpower) ID in the FUV is determined by the following relationship:

where P is the probability of defeat;

ΔР - overpressure in HCF, in kg/cm ² ;

Moreover, if ΔР≥7.0 kg/cm ² , then the probability of hitting the target Р=1.

4) If the defeat of the target is carried out due to the UID in the FUV, then it is determined by the given values \u200b\u200bof the distance from the point of detonation to the target

where ω _equiv is the equivalent mass of explosives, taking into account the effect of the mine shell, kg;

R - distance from the point of detonation to the target, m;

- коэффициент наполнения снаряда (таблица 2).

- projectile filling factor (table 2).

5) The probability of hitting the target UID is determined by the dependence:

where I _beats - UID in kPa⋅s.

Thus, the implementation of the first and second stages in the proposed method allows us to solve the technical problem.

The proposed method was tested experimentally by the authors.

Initially, preliminary experiments were carried out, where the equation of motion of the HCW was determined by measuring the time of arrival of the HCW at fixed points in space in the near zone of the explosion. The general view of the CFC is shown in Fig. 7. The pressure transducer mounting frame is shown in FIG. 8.

The experimental determination of the equation of motion of the FCF for the explosion of a charge from EVM-11 was carried out according to the scheme in a half-space (Fig. 1). The launch of the CMC was carried out automatically when a current pulse was applied to the electric detonator EDP-r with the registration of a zero time count by an ionization sensor installed on the initiator at the center of the charge (Fig. 2). The recording equipment was also stopped automatically after a specified time or number of measurements.

Ionization or high-frequency membrane sensors were used as sensors (Fig. 3, 4). As a result of each experiment, the CMC recorded sensor interrogation oscillograms, typical of which are shown in Fig. 9, 10. The equation of motion of the FUW (expression 1) was determined, while the coefficient of the squared Pearson correlation was χ ² =0.9558.

In the main series of experiments, the PFM was blasted in the soil with the measurement of the ASW parameters in the FUW (excessive pressure, FUW velocity, time of the ASW compression phase at a given point). The dependence of the pressure on the FCF and on the contact surface on the front coordinate is shown in Fig. 11. The dependence of the velocity of the particles of the HCF and on the contact surface on the coordinate of the front is shown in Fig. 12.

Thus, the new features with significant differences according to the proposed method are the following set of actions:

1. On the test site at a given distance from the test object, pressure sensors are placed and the PFM is blown up in the soil.

2. After the explosion of the PFM, the parameters of the air shock wave are determined (excessive pressure, the speed of the air blower, the time of the compression phase of the air shock) at a given point.

3. The coordinate law of destruction is determined in the form of the probability of defeating the target by excess pressure in the front of the shock wave or by the specific impulse of pressure at a given distance from the point of detonation of the studied PFM sample.

Thus, the proposed invention in the form of a method for assessing the damaging effect of PFM allows to obtain the required technical result.

Claims (1)

A method for assessing the destructive effect of anti-personnel high-explosive mines (PFM), including placing the PFM and pressure sensors on the test site, detonating the PFM, recording the parameters of the air shock wave, characterized in that the pressure sensors are placed on the test site at a given distance from the PFM, detonating the PFM is carried out in the soil with the measurement of the air shock wave parameters in the shock wave front, namely, the excess pressure in the shock wave front and the speed of the shock wave front, then the time of the compression phase of the shock wave front at a given point and the coordinate law of damage in the form of probability are determined destruction of a conditional target from excess pressure in the front of the shock wave or from the specific impulse of pressure at various distances from the place of rupture of the PFM.

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