RU2799294C1 - Method for testing perspective high-energy materials for sensitivity to mechanical stress - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: invention relates to devices and methods that ensure safety and can be used to test high-energy substances for sensitivity to mechanical stress. The method of testing high-energy substances for sensitivity to mechanical stress is that a high-energy substance is placed in a test layout and thermostated depending on the simulation of the conditions of the climatic zone. After temperature control, the layout is installed on a slipway with an armoured card. An armour-piercing incendiary bullet of 12.7 mm calibre is fired from an accelerating device mounted on a frame. The accelerating device is protected by an anti-ricochet gate. Fragments are collected. Each individual fragment is weighed and the average fragment mass is calculated using the following formula: М_AV = М₁ + М₂ + М₃ + …М_n/N_m, where M_AV is the average fragment mass, g; М₁ + М₂ + М₃ + …М_n is the sum of the masses of each individual fragment, g; N_m is the number of fragments (pcs). After that, according to the following formula, the E-criterion is determined, which falls into the ranges indicated below and determines the type of reaction: 1) 0<E<0,2 – combustion (type V); 2) 0,2<E<0,5 – deflagration (type IV); 3) 0,5<E<0,7 – explosive combustion (type III); 4) 0,7<E<0,9 – partial detonation (type II); 5) 0,9<E<1 – detonation (type I); E = (М_body-М_AV)/М_body, where E is the ranking criterion for determining the type of reaction; M_body is the mass of the mock-up body before testing, g; M_AV is the average weight of a fragment, g.

EFFECT: test of high-energy substances for sensitivity to mechanical stress, which provides for a visual and quantitative assessment.

1 cl, 14 dwg

Description

The invention relates to mechanical engineering, and in particular to methods that ensure safety, and can be used to test high-energy substances for sensitivity to mechanical stress.

Various types of ammunition filled with high-energy substances during transportation, operation, being in a combat zone can be subjected to such mechanical influences as hitting a fragment or a bullet, which in turn will lead to a reaction of the substance to this effect.

Currently, six types of BP reactions to hazardous external effects of HNS are classified:

Type I (Detonation reaction). The most powerful type of ammunition reaction. The supersonic decomposition reaction (detonation) takes place in the explosive material with the formation of an intense shock wave in the environment (for example, in air or water). Explosive material fully detonates. There is a very fast plastic deformation of the metal shells of the BP, accompanied by their complete crushing and the formation of small high-speed fragments. Explosive effects will include: large ammunition craters placed on or close to the ground surface; damage (penetration, fragmentation) of metal witness plates; explosive damage to nearby structures.

The primary sign of a Type I reaction is the formation of: a shock wave, the intensity of which corresponds to the complete detonation of the entire mass of explosive material in the BP and the formation of small high-velocity fragments from the BP shell.

Type II (Reaction of partial (incomplete) detonation). The second most powerful type of ammunition reaction. Some of the charge, but not all of the explosive material, reacts in a Type I manner (detonates). An intense shock wave is formed. Part of the shell of the ammunition is crushed into small fragments. Part of the BP shell can be crushed with the formation of large fragments. Metal witness plates can be damaged in the same way as in the case of a type I reaction. A funnel in the soil can form. Nearby structures can be damaged by the explosive shock wave. The magnitude of the effect depends on the mass fraction of the detonated bursting charge of the BP.

The primary indication of a Type II reaction is: the generation of an explosive shock wave, the intensity of which is less than that of the shock wave, which corresponds to the complete detonation of the entire mass of explosive material in the BP; rapid plastic deformation of a part (but not all) of the metal shell in contact with the explosive material, with its fragmentation into high-speed fragments.

A secondary sign of a Type II reaction is: scattered burnt or unburned explosive material; perforation, crushing and/or plastic deformation of the witness plate; the formation of a funnel in the ground.

Type III (Explosive combustion). The third most powerful type of ammunition reaction. Ignition and rapid combustion of the explosive material in the shell creates high local pressure rises, leading to the explosive destruction of the shell of the ammunition. The metal shell fragments (experiences blasting destruction) into large pieces, which are often scattered over long distances. Unreacted and/or burning explosive material is also scattered. An air shock wave occurs, which can cause the destruction of nearby structures. There is a danger of fire and smoke. Explosion and high-speed fragments can produce small craters in the ground and damage (destruction, penetration, recesses) in metal witness plates. The explosion pressure is lower than in type I and II reactions.

The primary symptom of a Type III reaction is the rapid combustion of some or all of the explosive material after the ammunition has started to react, and extensive cracking of the metal sheath with no evidence of shear deformation, resulting in fewer larger fragments than would occur during normal detonation of the ammunition charge.

A secondary symptom of a Type III reaction is: the scattering over considerable distances of pieces of burnt and unburned explosive material; witness plate damage; fixation of an explosive shock wave, the intensity of which is much less, and the duration is longer than that of an SW, which corresponds to the complete detonation of the entire mass of explosive material in the BP; the formation of a funnel in the ground.

Type IV (Deflagration reaction). Rapid combustion of explosive material without detonation. Ignition and combustion of explosives in the shell lead to non-explosive pressure release as a result of low strength or ventilation through the joints in the shell (a point for a detonator, threads, etc.). The shell may collapse, but not fragment; unburned or burning explosive material can be scattered and burn out. The release of pressure may move a loose test article, causing an additional hazard. There is no damage from the shock wave and significant fragmentation damage to surrounding objects; there are only thermal damage and smoke from the burning of explosive material.

The primary symptom of a Type IV reaction is the combustion of some or all of the explosive material and the rupture of the shell to form several large fragments. At least one fragment of the hull or ammunition charge flies off at a distance of more than 15 m from the location of the CU.

A secondary feature of a Type IV reaction is: a longer reaction time than in a Type III reaction; spread over considerable distances (more than 15 meters) of pieces of burnt and unburned explosive material; rise in overpressure at the test site, which may vary in time and space.

Type V (Combustion reaction). The explosive material of the ammunition charge ignites and burns. The shell may lose integrity (crack); it can melt or weaken significantly with a slow release of combustion gases, the joints of the shell can be displaced by internal pressure. The debris mostly remains in the burning zone, some fragments (bottoms, covers, etc.) can be thrown up to a distance of 15 meters. It is assumed that these fragments cannot cause fatal injuries to humans.

The primary symptom of a Type V reaction is low-pressure combustion of some or all of the explosive material. As a result, the body of the ammunition can collapse into several large fragments. There are no pieces flying off at a distance of more than 15 m from the location of the PSU. There are no signs of a reactive force capable of moving the ammunition over a distance of more than 15 meters. A small amount of pieces of burning or unburned explosive material compared to the total amount in the ammunition can be scattered within 15 meters, but no further than 30 meters from the location of the CU.

A secondary symptom of a Type V reaction is: some indication of slight pressure on the test site; for a rocket engine, a significantly longer reaction time than in the case of its normal launch [1].

This classification, as we can see, implies only a visual definition, not based on measurements and quantitative calculations. It is logical to assume that the visual definition in this case cannot claim sufficient reliability due to the difference in the subjective perception of people.

A known method is analogous to testing ammunition for bullet penetration, described in the MIL-STD-2105C standard, published on 07/14/2003 by the US Department of Defense. This standard describes the method of shooting through an ammunition with a bullet from a certain distance and provides a method for ranking according to the types of reactions of the substance equipped in the tested ammunition.

The disadvantage of this method should be attributed to the fact that in the standard, as mentioned above, they are distinguished from each other by visual inspection of the fragments after the reaction. This method is subjective and does not allow accurately (quantitatively), in other words, by calculation using the physical quantities obtained during the test, to determine the type of reaction of the substance to the piercing by a bullet.

A known method is a prototype of testing ammunition for shooting through a bullet, described in the article “On the development of ammunition with increased resistance to dangerous external influences and a method for testing them” UDC 662.215.11 (Terentiev A.B., Sonin N.S., Davydov D .R., Pyryev V.A., Koltunov V.V., Vatutin N.M.,), collection of the conference "Intra-chamber processes and combustion in solid fuel installations and barrel systems (ICOC' 2017)".

This article reflects the method of throwing a projectile from a certain distance at the ammunition in order to determine the presence of a reaction of a high-energy substance loaded into the ammunition.

For throwing a fragment, an installation with a ballistic barrel is used, in which the throwing of a fragment is carried out due to powder gases of high-energy gunpowder. The production of a shot from the installation is carried out using a pre-assembled unitary cartridge, consisting of a regular cartridge case, primer sleeve, reinforced powder charge from high-energy grades of gunpowder and a projectile. A projectile is a fragment located in a sector pallet. The latter is made from fluorine-containing polymer compositions with sufficient strength and high antifriction properties. The shot is carried out remotely using a cable mechanism for releasing the lock and lowering the percussion mechanism.

The disadvantage of the prototype method described in this article is that the projectile in this case is a fragment of a certain shape, consisting of fluorine-containing polymer compositions, which is a deviation from the real conditions. In addition, this method does not provide for quantitative ranking by types of ammunition reaction to lumbago, but only provides for the presence of a reaction, or its absence.

The technical result of the present invention is a method for testing high-energy substances for sensitivity to mechanical stress, simulating with high accuracy the real conditions of a bullet hitting an ammunition, followed by a numerical determination of the reaction of a high-energy substance. In addition, this method simulates different climatic zones (Tropical heat and the Far North), by pre-thermostating a high-energy substance.

The technical result is achieved as follows: in the method of testing high-energy materials for sensitivity to mechanical stress, a high-energy substance is placed on a test stand in a mock-up, a shot is fired, thermostated depending on the simulation of the conditions of the climatic zone, the shot is fired with an armor-piercing incendiary bullet of 12.7 mm caliber, fragments are collected layout, each individual fragment is weighed and the average fragment mass is calculated using the following formula:

(1),M _SR =

(1),

Where:

M _SR is the average mass of a fragment, grams;

M ₁ + M ₂ + M ₃ + ... M _n - the sum of the masses of each individual fragment; gram;

N _m is the number of fragments, pieces.

After that, according to the following formula, the E-criterion is determined, which falls into the ranges indicated below and determines the type of reaction:

1) 0 <E< 0.2 - Combustion (type V);

2) 0.2 <E< 0.5 – Deflagration (type IV);

3) 0.5 <E< 0.7 - Explosive combustion (type III);

4) 0.7 <E< 0.9 - Partial detonation (type II);

5) 0.9 <E<1 - Detonation (type I).

(2),E=

(2)

Where:

E - ranking criterion for determining the type of reaction;

M _corp is the mass of the mock-up body before testing, grams;

M _SR is the average mass of a fragment, grams.

The method of testing high-energy substances for sensitivity to mechanical stress is that a high-energy substance is placed in a test model, which is assembled according to the scheme shown in figure 1, where 1 is the body, 2 is the cover, 3 is a steel disk (end plates), 4-charge STRT, 5-bracket, 6-studs, 7-nuts, 8-wood beam, thermostatically controlled depending on the simulation of the conditions of the climatic zone. The scheme of tests for shooting through a bullet is shown in figure 2, where 9 is a layout, 10 is an armored card, 11 is a slipway, 12 is an anti-bounce gate; 13-accelerator (RU) caliber 12.7 mm (or 14.5 mm), 14-frame, 15-speed video camera. After temperature control, the model 9 is installed on the slipway 11 with the armored card 10. From the accelerating device 13, installed on the frame 14, an armor-piercing incendiary bullet of 12.7 mm caliber is fired. The accelerating device is protected by an anti-ricochet gate 12. The test process is recorded on a high-speed camera 15.

An example of shooting with a high-speed camera 15 is shown in the storyboard in Fig. 3.

Scraps are being collected. Each individual fragment is weighed and the average fragment mass is calculated using the following formula 1:

(1),M _SR =

(1),

Where:

M _SR is the average mass of a fragment, grams;

M ₁ + M ₂ + M ₃ + ... M _n - the sum of the masses of each individual fragment, grams;

N _m is the number of fragments, pieces.

After that, according to the following formula, E is determined - a criterion that falls into the ranges indicated below and determines the type of reaction.

1) 0 <E< 0.2 - Combustion (type V);

2) 0.2 <E< 0.5 - Deflagration (type IV);

3) 0.5 <E< 0.7 - Explosive combustion (type III);

4) 0.7 <E< 0.9 - Partial detonation (type II);

5) 0.9 <E< 1 - Detonation (type I).

(2),E=

(2)

Where:

E - ranking criterion for determining the type of reaction;

M _corp is the mass of the mock-up body before testing, grams;

M _SR is the average mass of a fragment, grams.

The method of testing high-energy substances for sensitivity to mechanical stress is illustrated by the following examples:

Example #1.

The mock-up, equipped with a standard formulation of mixed rocket solid propellants (SRTT), was subjected to temperature control at a temperature of -60 ° C, after which it was installed on a slipway with an armored card (Fig.4).

After that, an armor-piercing incendiary bullet of 12.7 mm caliber was fired from the accelerating device (Fig. 5).

The fragments of the body of the model collected for weighing after the shot are shown in Fig. 6.

= 207M _SR =

= 207

=

E=

=

As a result of the calculation according to the developed formulas, during the tests, the Detonation reaction (type I) was obtained.

Example #2.

The model, equipped with a standard recipe SRTT, was subjected to temperature control at a temperature of +60°C, after which it was installed on a slipway with an armored card (Fig.7).

After that, an armor-piercing incendiary bullet of 12.7 mm caliber was fired from the accelerating device (Fig. 5).

The fragments of the body of the model collected for weighing after the shot are shown in Fig. 8.

= 305M _SR =

= 305

=

E=

=

As a result of the calculation according to the developed formulas, during the tests, the reaction Partial detonation (type II) was obtained.

Example #3

The mock-up equipped with the standard SRTT recipe was subjected to temperature control at a temperature of -60 °C, after which it was installed on a slipway with an armored card (Fig. 9).

After that, an armor-piercing incendiary bullet of 12.7 mm caliber was fired from the accelerating device (Fig. 5).

The fragments of the body of the model collected for weighing after the shot are shown in Fig. 10.

= 620M _SR =

= 620

=

E=

=

As a result of the calculation according to the developed formulas, during the tests, the reaction Explosive combustion (type III) was obtained.

Example #4.

The mock-up, equipped with the standard SRTT recipe, was subjected to temperature control at a temperature of +60 °C, after which it was installed on a slipway with an armored card (Fig. 11).

After that, an armor-piercing incendiary bullet of 12.7 mm caliber was fired from the accelerating device (Fig. 5).

The fragments of the body of the model collected for weighing after the shot are shown in Fig. 12.

= 1230M _SR =

= 1230

=

E=

=

As a result of the calculation according to the developed formulas, during the tests, the Deflagration reaction (type IV) was obtained.

Example number 5.

The mock-up, equipped with the standard SRTT recipe, was subjected to temperature control at a temperature of +60 °C, after which it was installed on a slipway with an armored card (Fig. 13).

After that, an armor-piercing incendiary bullet of 12.7 mm caliber was fired from the accelerating device (Fig. 5).

The fragments of the body of the model collected for weighing after the shot are shown in Fig. 14.

= 1852M _SR =

= 1852

=

E=

=

As a result of the calculation according to the developed formulas, during the tests, the Combustion reaction (type V) was obtained.

Thus, this method of testing high-energy substances for sensitivity to mechanical stress is based on the existing classification of reaction types [1] and at the same time provides not only a visual, but also a quantitative assessment.

It should be noted that the ranking criterion E was determined by 300 experiments with various high-energy substances.

LIST OF USED LITERATURE

1. Matseevich, B.V. Ammunition of increased resistance to dangerous external influences: features of design, testing and operation [Text] / B.V.

Claims (16)

A method for testing high-energy materials for sensitivity to mechanical stress, which consists in the fact that a high-energy substance is placed on a test bench in a mock-up, a shot is fired, characterized in that the mock-up is thermostatted depending on the simulation of the conditions of the climatic zone, the shot is fired with an armor-piercing incendiary bullet of 12 caliber, 7 mm, collect the fragments of the layout, weigh each individual fragment and calculate the average fragment mass using the following formula: M _cf \u003d (M ₁ + M ₂ + M ₃ + ... M _n ) / N _m , where М _СР is the average fragment mass, g; M ₁ + M ₂ + M ₃ + ... M _n is the sum of the masses of each individual fragment, g; N _m is the number of fragments, pcs., the formula determines the E-criterion: E \u003d (M _corp - M _SR ) / M _corp , where E is the ranking criterion for determining the type of reaction; M _corp is the mass of the mock-up body before testing, g; М _СР is the average fragment mass, g, determine the type of reaction in accordance with the following ranges: 1) 0<E<0.2 – Combustion (type V); 2) 0.2<E<0.5 – Deflagration (type IV); 3) 0.5<E<0.7 - Explosive combustion (type III); 4) 0.7<E<0.9 - Partial detonation (type II); 5) 0.9<E<1 – Detonation (type I).

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