Protective structure against explosive effect of explosion

Abstract

FIELD: explosion protection.SUBSTANCE: invention relates to a method for protecting an object from explosive impact. The protective structure contains a non-assembled protective barrier. The barrier is equipped with a supporting structural element on the rear side in the sealing area. It is made in the form of a sheet, fixed at an angle to a non-set protective barrier along the sealing line, forming a triangle in cross-section. The space between the sealing line and the supporting structural element is filled with elastic filler.EFFECT: explosion resistance of the protective barrier is increased due to more rational use of its strength properties.1 cl, 3 dwg

Description

[0001] The invention relates to methods for protecting an object from the effects of an explosion and can be used in protective systems against underwater or air explosions.

[0002] A well-known design of side protection against underwater contact explosions, used on surface ships, consists of a number of longitudinal flat bulkheads located at specified distances from the side of the ship and forming chambers for absorbing the energy of detonation products and flying fragments. (Tsukshverdt A.E. Course in naval architecture. - Moscow: Military-Maritime Publishing House, 1951 - pp. 294-305). As a rule, one of the bulkheads, fixed to the support contour, is the main protective barrier, the task of which is to withstand the high-explosive effect of the explosion. To increase the energy capacity of the main protective barrier and, accordingly, its explosion resistance, it is made without reinforcement, which ensures its operation mainly on chain deformations.

[0003] A significant drawback of such barriers is the relatively high level of bending deformations occurring in the embedment area on the support contour, which ultimately determines their ultimate energy capacity before failure. When exposed to an explosion, the barrier's failure occurs in the area of ​​its support contour, where the ultimate deformation is reached in a localized area with a relatively low level of overall chain deformations.

[0004] A protective structure against the high explosive effect of an explosion is known (RU 2569978, IPC F42D 5 / 045, G12B 17 / 08, B63G 13 / 00, E04H 9 / 00, published 12 / 10 / 2015), including a non-assembled protective barrier, wherein on the rear side of the protective barrier, opposite the impact of the explosion, in the area of ​​​​the seal to increase the explosion resistance of the barrier, a supporting structural element is added to it in contact with it, made in one of two designs: a series of support knees with circular cuts with a common guide sheet welded to the cuts, or a series of similar knees with separate guide sheets, while the guide sheets are facing the protective barrier.

[0005] A disadvantage of this design is that, under the influence of an explosion, the non-prefabricated protective barrier can deform between the support brackets, resulting in the barrier's destruction near the support contour. Furthermore, the manufacture of curved hull parts and their assembly increases the labor costs of creating such a design.

[0006] A protective structure against the high explosive effect of an explosion is known (RU 2844294, IPC F42D 5 / 045, G12B 17 / 08, F41H 5 / 00, published on 28.07.2025), including a non-prefabricated protective barrier with a supporting structural element in the form of a sheet installed on the rear side of the protective barrier and oriented along the sealing line of the protective barrier, secured in such a way that the cross-section of the said structure is a plane perpendicular to the sealing line of the non-prefabricated protective barrier, wherein the protective structure additionally contains one or more sheet supporting structural elements oriented along the sealing line of the protective barrier, and the distance of each sheet supporting structural element from the sealing line of the protective barrier and the thickness of each sheet supporting structural element are selected by calculation.

[0007] The disadvantages of this design include high metal consumption and significant labor intensity of manufacture due to the need to install several sheet support structural elements.

[0008] The closest analogue adopted is a protective structure against the high explosive effect of an explosion (RU 2793121, IPC F42D 5 / 045, B63G 13 / 00, published on 03 / 29 / 2023), which includes a non-manufactured protective barrier, on the rear side of the protective barrier, opposite to the impact of the explosion, in the sealing area, a supporting structural element is installed, made in the form of a sheet, fixed at an angle to the non-manufactured protective barrier along the sealing line in such a way that the cross-section of the said structure by a plane perpendicular to the sealing line of the non-manufactured protective barrier has the shape of a triangle.

[0009] This design has a significant drawback: after the sheet support element loses stability, further growth of its supporting forces is impossible, leading to increased bending stresses in the non-prefabricated protective barrier. If a highly rigid support element is installed, significant bending deformations will be observed in the non-prefabricated protective barrier material at its installation location, which may lead to failure of the barrier not in the embedment, but at the location of the support element.

[0010] The invention solves the problem of increasing the resistance of a non-rigged protective barrier, fixed to a support contour, to the high-explosive effect of an explosion, by using additional supporting forces distributed over the area in the sealing area and the installation location of the supporting structural element, limiting the level of bending deformations in the sealing area, without significantly increasing the labor intensity of manufacturing and the metal content of the structure.

[0011] In order to obtain the required technical result in a protective structure against the high explosive impact of an explosion, including a non-prefabricated protective barrier, where on the rear side of the protective barrier, opposite to the impact of the explosion, in the sealing area, a supporting structural element is installed, made in the form of a sheet, fixed at an angle to the non-prefabricated protective barrier along the sealing line in such a way that the cross-section of the said structure by a plane perpendicular to the sealing line of the non-prefabricated protective barrier has the shape of a triangle, it is proposed to fill the space between the sheet supporting structural element and the sealing line of the non-prefabricated protective barrier with an elastic filler.

[0012] In the case of implementing the proposed design, the non-setting protective barrier in the embedding area is supported by forces from the sheet support structural element, as well as by support forces distributed over the area from the elastic filler, as a result of which the growth of bending deformations in the embedding area and the installation site of the sheet support structural element is prevented, thereby preventing the destruction of the non-setting protective barrier in this area.

[0013] The attached graphic materials show:

[0014] Fig. 1 - general view of the protective structure against the explosive impact of an explosion;

[0015] in Fig. 2 - calculation schemes of a beam-strip, separated from a non-prefabricated protective barrier;

[0016] in Fig. 3 - the dependence of the relative magnitude of the bending moment acting in the beam-strip of the non-rigged protective barrier in the embedment and at the installation site of the sheet support structural element on the relative magnitude of the external load.

[0017] The following symbols are used in graphic materials:

[0018] 1 - non-set protective barrier;

[0019] 2 - sheet supporting structural element;

[0020] 3 - elastic filler;

[0021] L - length of the beam-strip, separated from the non-rigged protective barrier, m;

[0022] - distance from the sealing of the non-assembled protective barrier to the connection with the sheet supporting structural element, m;

[0023] - width of the sheet supporting structural element, m; q - intensity of the external distributed load, N / m;

[0024] q0 - intensity of external distributed load corresponding to reaching the limit value by the longitudinal force in the beam-strip of a non-rigged protective barrier in the absence of sheet supporting structural elements, N / m;

[0025] - relative value of external distributed load;

[0026] R - vertical component of the reactive force acting on the beam-strip of a non-rigged protective barrier from the side of the sheet supporting structural element, N;

[0027] z1- coordinate measured along the section of the beam-strip without set

[0028] protective barrier between the seal and the sheet supporting structural element, m;

[0029] z2 - coordinate measured along the section of the beam-strip of the non-rigged protective barrier between the sheet supporting structural elements, m;

[0030] - elastic line of the section of the beam-strip of the non-rigged protective barrier between the seal and the sheet supporting structural element, m;

[0031] - elastic line of the section of the beam-strip of the non-rigged protective barrier between the sheet supporting structural elements, m;

[0032] K(z1) - the coefficient of rigidity of the elastic base, the role of which is played by the elastic filler, which varies along the length of the beam-strip of the non-setup protective barrier,

[0033] K0 - average value of the stiffness coefficient of the elastic base of the beam-strip of the non-rigged protective barrier, the role of which is played by the elastic filler,

[0034] T - longitudinal force acting in the beam-strip of a non-rigged protective barrier, N;

[0035] M - bending moment acting in the beam-strip of a non-rigged protective barrier, Nm;

[0036] - bending moment acting in the embedding of a strip beam of a non-rigged protective barrier in the absence of a sheet support structural element and an external load intensity of q0, N m;

[0037] - the relative value of the bending moment acting in the beam-strip of a non-rigged protective barrier;

[0038] - the relative value of the bending moment acting in the embedding of the beam-strip of a non-rigged protective barrier in the absence of a sheet supporting structural element;

[0039] - the relative value of the bending moment acting in the embedding of the beam-strip of a non-rigged protective barrier in the case of installation of a sheet support structural element in accordance with the design of the closest analogue;

[0040] - the relative value of the bending moment acting in the embedding of the beam-strip of a non-rigged protective barrier in the case of the implementation of the proposed design;

[0041] - the relative value of the bending moment acting in the beam-strip of a non-rigged protective barrier at the location of the installation of a sheet support structural element in the case of the implementation of the proposed design.

[0042] The protective structure against the high explosive impact of an explosion consists of a non-prefabricated protective barrier 1 and a sheet support structural element 2 installed in the sealing area; the space between the sealing of the non-prefabricated protective barrier 1 and the sheet support structural element 2 is filled with an elastic filler 3.

[0043] The protective structure against the high explosive impact of an explosion operates as follows. The non-prefabricated protective barrier 1 is deformed in the area of ​​the support contour under the influence of blast loads, causing support forces to arise from the sheet support structural element 2, acting along the line along the embedment. Furthermore, in the section of the non-prefabricated protective barrier 1 located between the embedment line and the installation location of the sheet support structural element 2, the non-prefabricated protective barrier is supported by distributed reactions from the elastic filler 3. The level of bending deformations of the non-prefabricated protective barrier 1 in the specified area is reduced due to the action of support forces, the magnitude of which is determined by the rigidity of the sheet support structural element 2 and the elastic filler 3.This leads to a decrease in the level of maximum deformations and their redistribution towards a significant increase in the proportion of chain deformations before destruction, which, in turn, leads to an increase in the energy capacity of the non-rigged protective barrier 1 and its ultimate resistance to the high-explosive action of an explosion.

[0044] To evaluate the effectiveness of the proposed technical solution, a strip beam (Fig. 2) should be considered as a first approximation. It is separated from a non-framework protective barrier 1, loaded with an explosive load, supported by the reactions of sheet support structural elements 2, and operating in a state of complex bending. The section of the strip beam between the embedment and the support rests on an elastic foundation with a stiffness K(z1) varying along the length of the strip beam. It is advisable to analyze such a strip beam by dividing it into sections. Given the symmetry of the structure, it is sufficient to consider only its left part. Thus, the first section is located between the seal and the support, and to describe its deformation one can use the equations of complex bending of a beam lying on an elastic foundation, presented, for example, in (Korotkiy Ya.I., Postnov V.A., Sivere N.L. Structural mechanics of a ship and the theory of elasticity. In 2 vols. Vol. 1. - L.: Shipbuilding, 1968. - 424 p., pp. 125-134).The second section is located between the supports, operates in a state of complex bending and its deformation is described according to (Papkovich P.F. Works on structural mechanics of the ship. In 4 volumes. T.Z. Complex bending of rods and bending of plates. - L.: Sudpromgiz, 1962. - 527 p., pp. 5-85.). The magnitude of the longitudinal force can be determined from the deformation compatibility equation according to (Burakovsky E.P., Nechaev Yu.I., Burakovsky P.E., Prokhnich V.P. Operational strength of ships: textbook. - St. Petersburg: Lan, 2017. - pp. 49-88). The calculation scheme of the beam-strip, isolated from the non-rigging protective barrier 1, is shown in Fig. 2. As a first approximation, it can be assumed that until the compressive force in the sheet support structural elements 2 reaches its Euler load, they represent rigid supports for the strip beam of the non-framing protective barrier. After loss of stability, the reactions of the sheet support structural elements 2 can be taken to be equal to their Euler load.A more accurate determination of bending and chain forces is possible using calculation methods based on the implementation of the hypothesis “on the instantaneous opening of plastic hinges” (Burakovsky E.P., Nechaev Yu.I., Burakovsky P.E., Prokhnich V.P. Operational strength of ships: textbook. - St. Petersburg: Lan, 2017. - Pp. 49-88).

[0045] When considering the first section of the beam-strip of the non-framing protective barrier 1 (between the embedment and the installation location of the sheet supporting structural element 2), in the first approximation, the stiffness coefficient of the elastic foundation, the role of which is played by the elastic filler 3, can be taken equal to its average value Ko along the entire length of the first section. In accordance with the above, the deformation of the beam-strip, isolated from the non-framing protective barrier 1, in the first section according to (Korotkiy Ya.I., Postnov V.A., Sivere N.L. Structural mechanics of a ship and the theory of elasticity. In 2 vols. Vol. 1. - L .: Shipbuilding, 1968. -424 p., pp. 125-134) is described by the equation

[0046] where E is Young's modulus, Pa;

[0047] μ - Poisson's ratio;

[0048] I - moment of inertia of the cross-section of the beam-strip of a non-rigged protective barrier, m 4 ;

[0049] T - longitudinal force acting in the beam-strip of a non-rigged protective barrier, N;

[0050] q - intensity of external distributed load, N / m;

[0051] z1 - coordinate measured along the section of the beam-strip of the non-rigged protective barrier between the seal and the sheet supporting structural element, m;

[0052] - elastic line of the section of the beam-strip of the non-rigged protective barrier between the seal and the sheet supporting structural element, m;

[0053] K0 - average value of the stiffness coefficient of the elastic base of the beam-strip of the non-rigged protective barrier, the role of which is played by the elastic filler,

[0054] In the case of a distributed load, the intensity of which does not change along the length of the beam-strip, the general integral of the differential equation (1) in accordance with (Korotkiy Ya.I., Postnov V.A., Sivere N.L. Structural mechanics of a ship and the theory of elasticity. In 2 vols. Vol. 1. - L.: Shipbuilding, 1968. - 424 p., pp. 125-134) has the form:

[0055]

[0056] where - parameter;

[0057] - parameters, m -1 ;

[0058] C1, C2, C3, C4 - constants of integration determined from the boundary conditions, m.

[0059] To obtain a more accurate solution, the first section can be divided into several parts and a constant elastic stiffness coefficient can be adopted for each part. In this case, the deformation process of each part of the first section will be described by an equation of the form (2), and at the boundaries of the parts, the integration constants C1, C2, C3, and C4 will be determined based on the condition that all bending parameters of the mating parts at the mating point are equal.

[0060] In the second section, the deformation of the beam-strip of the non-rigged protective barrier 1 can be described by the equation

[0061]

[0062] where E is Young's modulus, Pa;

[0063] μ - Poisson's ratio;

[0064] I - moment of inertia of the cross-section of the beam-strip of a non-rigged protective barrier, m 4 ;

[0065] T - longitudinal force acting in the beam-strip of a non-rigged protective barrier, N;

[0066] q - intensity of external distributed load, N / m;

[0067] z2 - coordinate measured along the section of the beam-strip of the non-rigged protective barrier between the sheet supporting structural elements, m;

[0068] - elastic line of the section of the beam-strip of the non-rigged protective barrier between the sheet supporting structural elements, m.

[0069] In the case of a distributed load, the intensity of which does not change along the length of the beam-strip, the general integral of the differential equation (3) in accordance with (Papkovich P.F. Works on the structural mechanics of a ship. In 4 vols. Vol. 3. Complex bending of rods and bending of plates. - L.: Sudpromgiz, 1962. - 527 p., pp. 5-85.) has the form:

[0070]

[0071] where - parameter, m -1 ;

[0072] B0, B1, B2, B3 - integration constants determined from the boundary conditions, m;

[0073] - auxiliary functions

[0074] It should be noted that strengthening the protective barrier requires only a slight increase in the weight of the protective structures, which is a significant advantage of the proposed technical solution. With the same additional weight, compared to increasing the protective barrier's thickness, it significantly improves its explosion resistance, which is essential when designing optimal structures with minimal weight characteristics. The proposed technical solution increases the energy capacity of the protective barrier before failure. This is achieved by limiting the level of bending deformation in the seal area during an explosion to the required value, determined by the parameters of the sheet support structural element and the thickness of the non-prefabricated protective barrier.

[0075] As an example, let us consider a non-prefabricated protective barrier with the following parameters: length L = 3 m, thickness t = 0.02 m. As a sheet supporting structural element, we use a strip with a width installed at an angle of 45° to the plane of the non-rigged protective barrier 1 (thus, the thickness of the sheet supporting structural element 2 will be taken as t n = 0.008 m. As elastic filler 3 we will take polyurethane foam with an apparent density of 159 kg / m3 3, having a modulus of elasticity E = 72.7 MPa (Berlin A.A., Shutov F.A. Polymer foams based on reactive oligomers. - M.: "Chemistry", 1980. - 296 p., pp. 90-94.). It should be noted that, depending on the apparent density of polyurethane foam, its modulus of elasticity varies within a wide range, which makes it possible to select a material with the required rigidity for various parameters of the non-setting protective barrier 1. The calculation results are presented in Fig. 3, which shows that in the proposed design, the moment in the embedment and the moment at the support does not exceed 0.4. In this case, the bending moment in the sealing of the structure of the closest analogue reaches the value With the same parameters of the sheet support structural element. It is evident that the proposed design allows for a significant reduction in bending stresses in the sealing of the self-supporting protective barrier 1, thereby increasing its effectiveness.

[0076] Thus, the proposed design, in comparison with the design of the closest analogue, allows for increasing the resistance of a non-assembled protective barrier without significantly increasing the labor intensity of manufacturing and the metal content of the structure.

Claims

A protective structure against the high explosive impact of an explosion, including a non-prefabricated protective barrier, on the rear side of the protective barrier, opposite to the impact of the explosion, in the sealing area, a supporting structural element is installed, made in the form of a sheet, fixed at an angle to the non-prefabricated protective barrier along the sealing line in such a way that the cross-section of said structure by a plane perpendicular to the sealing line of the non-prefabricated protective barrier has the shape of a triangle, characterized in that the space between the sheet supporting structural element and the sealing line of the non-prefabricated protective barrier is filled with an elastic filler.

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