RU2443966C1 - Artillery shell - Google Patents

Abstract

FIELD: weapons and ammunition.

SUBSTANCE: shell comprises a casing, a front section, a warhead and a rear compartment with a device to increase range ability. The device for increasing range ability comprises an accumulating tank and a throttling device. The device for increasing range ability is equipped with a support corrugate disc and a radially corrugate membrane. Radial corrugations of the membrane and appropriate corrugations in the support disc are arranged with alternate depth proportional to the ratio between the diameter of the axis of symmetry of this corrugation and the average diameter of the corrugate part. Geometric dimensions of corrugations are related according to the following dependence:

where h_i - depth of i corrugation, K - coefficient that characterising the permissible plastic deformation of the membrane material, r - radius of membrane ends rounding, D_i - diameter of the axis of symmetry of i corrugation, D_av - the average diameter of the corrugated part of the membrane, i - order number of the corrugation, counting from the membrane centre.

EFFECT: increase of shell flying range.

3 dwg

Description

The invention relates to ammunition, in particular to artillery shells, in which, in order to increase the flight range when the projectile moves along the barrel, the energy of the gases in the projectile space is accumulated in the projectile, and after the projectile leaves the barrel, the aft part is lengthened, giving it a conical shape form.

An analogue of the proposed device is an artillery shell with a deformable aft part in flight (RF patent No. 2358228 in class F42B 10/38 with priority of 08/13/2007, published on 06/10/2009). An artillery shell comprising a body with a head compartment with a warhead and aft compartment with a device for increasing flight range, comprising a storage chamber and a throttle device, while a support ring and a corrugated membrane with a central hole are introduced into the device for increasing flight range, the corrugated membrane being rigidly mounted on the outer diameter of the aft compartment, resting on the outer end surface of the storage chamber, and the corrugated membrane is made with half overlap corrugation rings, the radial width of which is determined by the following relationship:

where 1 _i is the radial width of the i-th corrugation,

d _{i cf} - the average diameter of the i-th corrugation,

K is the coefficient characterizing the allowable plastic deformation of the membrane material.

The above analogue has several disadvantages:

- overlapping corrugation requires the use of a protective cap that protects the thin-walled membrane corrugations from mutual deformation and collapse;

- the manufacture of a membrane of this form is quite difficult in the technological plan and requires significant material costs.

The closest analogue of the proposed device is an artillery shell (RF patent for PM No. 92169 in class F42B 10/38 with priority dated October 16, 2009, published on March 10, 2010). An artillery shell comprising a body with a head compartment, a warhead and aft compartment with a device for increasing flight range, comprising a storage chamber and a throttle device, while the device for increasing flight range is provided with a support corrugated disk and a radially corrugated membrane superimposed on the corresponding profile disk corrugation and fixed on its outer surface, and in the center of the disk is installed a throttle device with the possibility of axial movement, mounted on the membrane, p and this corrugated diaphragm is formed as a plurality of zigzag corrugation coaxial with rounded ends along the radius r, between which there are cylindrical portions of a width h in the following ratio of geometrical sizes:

where K is the coefficient characterizing the allowable plastic deformation of the membrane material.

The above prototype has several disadvantages:

- the same width of the cylindrical sections, independent of the current radius, leads to uneven stresses in the membrane after deformation;

- the manufacture of a membrane of this form is quite difficult due to the high degree of deformation of the corrugations located near the center of the membrane;

- with equal width of corrugations having different radii, their degrees of deformation will differ, which will lead to uneven deformation of the membrane.

The technical task of the present invention is to increase the flight range of an artillery shell by improving aerodynamic quality by reducing the bottom drag by giving the aft of the projectile in flight a smoothly streamlined flow of air without changing the standard dimensions of the projectile before firing and with a minimum mass of the transformed aft part.

The problem is solved in such a way that an artillery shell containing a body with a head compartment, a warhead and aft compartment with a device for increasing flight range, which includes a storage chamber and a throttle device, the device for increasing flight range is equipped with a support corrugated disk and a radially corrugated the membrane, while the radial corrugations of the membrane and the corresponding corrugations in the support disk are made with a variable depth proportional to the ratio of the diameter of the axis of symmetry corrugation given to the average diameter of the corrugated portion, wherein the geometrical dimensions of the corrugations connected dependence

where h _i - the depth of the i-th corrugation,

K - coefficient characterizing the allowable plastic

deformation of the membrane material,

r is the radius of curvature of the ends of the membrane,

D _i - the diameter of the axis of symmetry of the i-th corrugation,

D _cp is the average diameter of the corrugated part of the membrane,

i - serial number of the corrugation, counting from the center of the membrane.

Figure 1 shows a General view of an artillery shell with a device for increasing flight range.

Figure 2 shows a cross section of a corrugated membrane indicating the main geometric parameters.

Figure 3 shows a view of an artillery shell after the device is activated to increase flight range.

This ratio of the geometrical dimensions of the corrugated membrane will make it possible to obtain a deformed fairing that optimally satisfies the conditions for ensuring an uninterrupted flow of air around the aft part of the projectile, and also ensures uniform deformation of all corrugations of the membrane.

The projectile contains a housing 1 with a head 2 and aft 3 compartments. The warhead is located in the head compartment 2. In the aft compartment 3 there is a device for increasing flight range, made in the form of a deformable tail fairing, which contains a radially corrugated membrane 4, the outer edge of which is rigidly fixed on the supporting corrugated disk 5, and in its center is a throttle device 6 connecting the projectile space 7 with the accumulation chamber 8 formed by the bottom cut of the projectile and the supporting corrugated disk 5. The length of the generatrix of the expanded cone is selected based on the condition of providing a taper angle of 20 °, while odrazumevaetsya that radial bellows not only straightens, but also stretched. To take this fact into account, a coefficient K characterizing the allowable plastic deformation of the membrane material and equal to the value of the allowable elongation of the membrane material δ was introduced into the formula relating the width of the cylindrical section and the radius of curvature of the radially corrugated membrane. The values of δ (V.I. Anufriev “Handbook of the designer-mechanical engineer”) are, for example, for Steel 15 - 0.2; for VT1-00 alloy - 0.25. The throttle device 6 is designed in such a way that does not allow the rapid outflow of high pressure gas from the storage chamber 8 when the artillery shell leaves the barrel. The location of the throttle device in the center of the radially corrugated membrane 4 allows to exclude the influence of a gas stream flowing from the storage chamber 8 on the flight path of the artillery shell. The arrows p _k and p _vn show the gas pressure acting on the radially corrugated membrane 4 when it is deformed (p _k - in the barrel, p _k - when the membrane is deformed in free flight).

The artillery shell works taking into account the above description as follows.

When fired by powder gases, the projectile is accelerated in the barrel and at the same time, throttle device 6 accumulates high-pressure gas in the storage chamber 8, formed by the bottom cut of the projectile and the corrugated supporting disk 5. The corrugated membrane 4 is compressed when the projectile is in the barrel to the supporting corrugated disk 5, therefore, to ensure the necessary strength of the structure does not require a large thickness of its walls. After the projectile leaves the barrel, the ambient pressure (pressure behind the bottom cut of the projectile) becomes much lower than the gas pressure in the storage chamber 8. Due to the pressure difference, the throttle device 6 begins to move in the axial direction, while the radially corrugated membrane 4 begins to straighten and lengthen under the action internal pressure, acquires a convenient form for flowing around the air stream. The straightened and elongated radially corrugated membrane 4, due to its initial shape, ultimately forms a tail cone in the form of a cone with an angle of inclination of the generatrix to the longitudinal axis of 20 °, this allows to minimize the bottom aerodynamic drag and thereby increase the flight range of the artillery shell.

Using the proposed device will reduce the coefficient of total aerodynamic drag of the projectile by 25-30%, which will lead to an increase in the range of the projectile by 15-20%. These performance indicators of the proposed solutions are confirmed by the results of numerical simulation of the flight of a modernized artillery shell.

Claims (1)

An artillery shell comprising a body with a head compartment, a warhead and aft compartment with a device for increasing flight range, which includes a storage chamber and a throttle device, the device for increasing flight range is equipped with a corrugated support disk and a radially corrugated membrane, characterized in that the radial the corrugations of the membrane and the corresponding corrugations in the support disk are made with a variable depth proportional to the ratio of the diameter of the axis of symmetry of this corrugation to the average diameter corrugated part, while the geometric dimensions of the corrugations are related by:

,
where h _i - the depth of the i-th corrugation,
K is the coefficient characterizing the allowable plastic deformation of the membrane material,
r is the radius of curvature of the ends of the membrane,
D _i - the diameter of the axis of symmetry of the i-th corrugation,
D _cf - the average diameter of the corrugated part of the membrane,
i - serial number of the corrugation, counting from the center of the membrane.

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