RU51721U1 - SCREEN FOR PROTECTION AGAINST HIGH SPEED SHards - Google Patents

Abstract

The utility model relates to the field of technology for providing protection from high-speed fragments generated during the explosion of explosive charges (BB) having metal outer shells and inner liners. The technical task to be solved is to develop a screen that provides effective protection of the object or walls of the protective device from high-speed fragments generated during the explosion of explosive charges with the body. (57) The essence of the solution is a screen for protection against high-speed fragments, consisting of sequentially arranged layers of metal wire woven mesh installed close to each other, forming a packet of a given density, and the number of layers (n) of the packet is selected from the relation: n = kΔ, where Δ is the maximum penetration depth of a carbon steel sheet screen in mm, k is an empirical coefficient of 8 mm ^-1 . The expected technical result from the use of the device is to prevent damage to the walls of the explosion-proof container when the explosive charge with the shell explodes in it, as well as to prevent the detonation of neighboring explosive charges during group transportation or storage in the event of unauthorized explosion of one of them.

Description

The utility model relates to the field of technology for providing protection from high-speed fragments generated during the explosion of explosive charges (BB) having metal outer shells and inner liners.

In the explosion of such explosive charges, high-speed fragments with high penetration ability can form. You can protect yourself from these fragments, for example, with sheet steel screens. However, such screens have a number of drawbacks related mainly to the high acoustic rigidity of steel, as a result of which the total impulse of the explosion pressure is transmitted almost unchanged to the protected object (there is no damping), secondary fragments can form due to the development of spalling phenomena in the screen or destruction of the screen into fragments that also have great breakdown ability. The indicated disadvantages are deprived of shatterproof screens from a metal mesh.

Known explosion-proof chamber according to patent RU No. 2228515, published on 10.05.2004 bull. No. 13. The explosion-proof chamber contains a cylindrical metal multilayer body with two bottoms, one of which has a loading hole with a neck, hermetically sealed on the outside with a lid, and anti-splinter protection made in the form of layers of a metal mesh located on the inner surfaces of the housing, bottoms and power cover.

The disadvantage of this device is the lack of ratios that allow you to select the number of layers of the mesh that protects against the damaging effects of fragments generated during the explosion of a specific explosive charge, the body and bottom of the chamber, and to form an optimal protective package in terms of thickness (respectively weight). Also in the description

The technical solution does not provide the actual density of the laminated bag, which in turn significantly affects the protective properties of the anti-shatter protection.

Known armor protection from bullets with a steel core according to the application RU 2001104691 from 02.19.2001, published 01.20.2003. Armor protection is made of metal nets with a mesh size from half to one caliber of the bullet, characterized in that the mesh is made of wire with a hardness not less than the hardness of the bullet core.

The disadvantage of this device is the strict requirement for the amount of hardness for the wire, which limits the choice of material of the wire.

The closest analogue is the explosion-proof pillow according to the patent US 5576511, published 19.11.96. The explosion-proof pillow contains the first and second layers of steel cells located at a certain distance from each other, an inner layer of cut metal foil and a filler layer with a thickness of at least 10 cm made of many ellipsoids from a metal mesh.

The disadvantage of this device is the lack of an ordered structure of the protective layer, which reduces the effectiveness of protection against high-speed fragments.

In all analogues, the possibilities of using the proposed armor protection from high-speed fragments are not considered.

The fragments generated by the explosion of charges having metal outer shells and inner liners pose the greatest danger to objects located nearby, as they can cause damage, and if the object contains an explosive charge, then it will explode. If a protective device (explosion-proof chamber) is used to reduce the consequences or localize the explosion inside the volume limited by its walls, these explosion factors can damage the walls of this device and

lead to the loss of its tightness, or even cause the destruction of the entire device into parts, i.e. cause the device to fail to perform protective functions.

The technical task to be solved is to develop a screen that provides effective protection of the object or walls of the protective device from high-speed fragments generated during the explosion of explosive charges with the body.

The expected technical result from the use of the device is to prevent damage to the walls of the explosion-proof container during the explosion of an explosive charge with a case in it, as well as to prevent the detonation of adjacent explosive charges during group transportation or storage in the event of unauthorized explosion of one of them.

The specified technical problem is solved using the screen, which is n layers of metal wire woven mesh.

A new one is the sequential, close to each other arrangement of the grid layers and the experimentally established dependence of the choice of screen parameters for protection from the field of fragments that are formed during the explosion of various charges, causing damage in the form of craters to the walls of a protective structure (explosion-proof chamber) or to nearby objects, including including explosive.

The number n of grid layers, for a given packet density, is selected from the condition:

n = kΔ, where

Δ is the maximum penetration depth of the screen of carbon steel sheet in mm,

k = 8 - empirical coefficient in mm ^-1 , taking into account factors affecting the choice of screen. So, the penetration depth of a grid packet with fragments of natural crushing depends on the approach speed, material (density, strength parameters) and dimensions (mass, parameters

the shape, cross-section of the fragment with which it interacts with the screen) of fragments, which in turn are determined by the design and mass of explosive charges (EX) with metal outer shells and inner liners.

The screen is a package of n layers of woven wire mesh (PTS), installed close to each other with an average specified stacking density ρ = 1.2 ± 0.3 g / cm ³ .

Samples of the screen from a woven wire mesh with a mesh size of 2 × 2 mm and a wire diameter of 0.5 mm were tested in experiments with explosive charges in a metal outer casing, during the explosion of which high-speed fragments were formed, having a maximum speed of up to ~ 3 km / s. In similar experiments, fragments, acting on flat screens made of carbon steel sheet, led to their damage and the appearance on their surface facing the explosion, craters of various depths.

The striking ability of fragments from explosive charges with various metal outer shells and inner liners was characterized by Δ - the maximum depth (in millimeters) of craters formed on a flat screen made of carbon steel sheet.

Technical feasibility is confirmed by the following examples.

1. To protect against explosive charge fragments with a case causing penetration of a steel sheet screen to a depth of Δ≤29 mm, it is required to use a mesh screen with the number of layers n = 8 * 29 = 232 from the stated ratio. In reality, the following were established in the experiment: a screen made of a metal mesh with the number of layers n = 80 and after it an additional screen made of carbon steel sheet. The through penetration of 80 layers of the grid and damage on the steel screen installed behind the grid was obtained with a maximum crater depth of 19 mm. If you replace an additional

steel screen with a screen from the grid, selecting the number of its layers from the condition n = 8 * A, we get the total number of layers of the grid necessary to protect against fragmentation: 80+ (8 * 19) = 232, which corresponds to the screen from the grid selected by the stated ratio.

2. To protect against explosive charge fragments with a housing causing penetration of a steel sheet screen to a depth of Δ≤40 mm, a screen made of a metal mesh with the number of layers n = 8 * 40 = 320 is required according to the stated ratio.

In the experiment, 280 layers of the mesh were found, of which 240 were penetrated, the remaining 40 layers had dents. Those. a screen of 320 layers selected according to the claimed ratio will uniquely protect the object from fragments of this charge with the body.

3. To protect against explosive charge fragments with a case causing through penetration of a steel sheet screen Δ≈35 mm, a screen made of a metal mesh with the number of layers n≈8 * 35 = 280 is required according to the stated ratio.

In the experiment, a screen of 280 mesh layers was installed, of which all received through penetration. However, the steel sheet screen mounted behind the net did not have any damage. Those. a screen of 280 layers selected according to the stated ratio protected the object from fragments of this charge with the body.

The effective action of protection from a woven wire mesh is associated with damping of the total burst pressure pulse and the possibility of fragmentation (destruction) of fragments into smaller parts when interacting with individual layers of the mesh as they are introduced into the packet and distributed over a large area of their momentum in the direction perpendicular to the direction of penetration .

Claims (1)

A screen for protection against high-speed fragments, consisting of sequentially arranged layers of a metal wire woven mesh, characterized in that the layers are installed close to each other, forming a packet of a given density, and their number n is selected from the ratio: n = kΔ where Δ is the maximum penetration depth of the screen of carbon steel sheet, mm; k is an empirical coefficient equal to 8 mm ^-1 .