Deepwater explosion shock wave loading method and system based on elliptical reflection principle

Abstract

The invention discloses a deepwater explosion shock wave loading method and system based on the elliptical reflection principle, belonging to the technical field of submarine and submersible structure design, wherein the method comprises: using the elliptical reflection principle to determine the focus A and B positions in a preset ellipsoid test device; determining the size of the test structure; setting the preset explosion source at A, placing the test structure at B, and arranging the detonation line and the test equipment; filling the interior of the preset ellipsoid test device with water, and pressurizing it to the preset hydrostatic pressure, and checking whether the test equipment works normally; detonating the preset explosion source to start the test, and collecting test data according to the preset collection time; removing the unreal signal in the test data, obtaining the deepwater explosion shock wave, and solving the surface load distribution of the test structure according to the deepwater explosion shock wave. The method effectively utilizes the elliptical reflection principle, avoids the influence of the shock wave reflected by the tank wall on the test structure, and improves the accuracy of the pressure tank simulation deepwater explosion damage test.

Description

Technical Field

[0001] The invention relates to the technical field of submarine and submersible structure design, and in particular to a deep-water explosion shock wave loading method and system based on the elliptical reflection principle. Background Art

[0002] The damage test technology of warheads in deep water environment is a key technical issue in damage assessment and is also the current technical bottleneck. If a full-scale model test is carried out in a real sea area, not only will the model be expensive, but the test in a real deep water environment will be extremely difficult. Factors such as high hydrostatic pressure and complex marine environment have brought great challenges to the test organization, test operation and data measurement, resulting in excessively high test costs. The repeatability of the test and a sufficient number of tests are the guarantee of the convincingness of the test results. Therefore, conducting deep-sea explosion model tests in a simulated environment is a better choice to verify the damage effectiveness of the warhead. However, current deep-sea explosion tests mainly rely on explosion tanks, but the boundaries of the explosion tanks will reflect the shock waves, causing the structure to suffer damage different from that in a free deep water environment.

[0003] The shock wave on the frontal explosion surface in deep water is superimposed with the hydrostatic pressure, and on the back explosion surface, the shock wave propagates around the cylindrical shell to generate an expansion wave. The superposition of the expansion wave and the incident shock wave causes the temporal and spatial distribution of the pressure on the back explosion surface of the cylindrical shell to be significantly different from that on the front explosion surface. However, in terms of its overall distribution, the back explosion surface of the cylindrical shell is still an uneven compression wave. Therefore, the surface pressure on the front explosion surface and the back explosion surface of the cylindrical shell structure is seriously inconsistent with the actual situation.

[0004] In summary, how to design a deep-sea test device that avoids the influence of reflection on the structure is a technical problem that needs to be solved urgently. For deep-water explosion tests, there are some related patents for test devices, such as "A pressure vessel that simulates the explosion of explosives under deep-water static pressure" (patent application number 201910971161.8), which provides a pressure vessel that simulates the explosion of explosives under deep-water static pressure. The test device is mainly aimed at realizing the study of deep-water explosion experimental phenomena, but it fails to effectively consider the influence of factors such as reflected shock waves on the pressure vessel wall on the test structure; "A deep-water explosion chamber (patent application number 201720024044.7)", the patent discloses a deep-water explosion chamber, which is mainly aimed at 10g TNT equivalent and below deep-water explosion tests, and cannot test submarine and other compartment model structures, and it fails to effectively consider the influence of factors such as reflected shock waves on the pressure vessel wall on the test results.

[0005] Therefore, there is an urgent need for a technical solution to overcome the influence of reflected shock waves on the test that exist in existing deep-water explosion pressure vessels. Summary of the invention

[0006] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0007] To this end, an object of the present invention is to propose a deepwater explosion shock wave loading method based on the elliptical reflection principle, which overcomes the problem of the influence of reflected shock waves on the test existing in existing deepwater explosion pressure vessels.

[0008] Another object of the present invention is to provide a deep-water explosion shock wave loading system based on the elliptical reflection principle.

[0009] Another object of the present invention is to provide a computer device.

[0010] Another object of the present invention is to provide a non-transitory computer-readable storage medium.

[0011] To achieve the above-mentioned purpose, an embodiment of the present invention proposes a deep-water explosion shock wave loading method based on the elliptical reflection principle, comprising the following steps: step S1, using the elliptical reflection principle to determine the focus A position and the focus B position in a preset ellipsoid test device; step S2, determining the size of the test structure; step S3, setting a preset explosion source at the focus A position, placing the test structure at the focus B position, and arranging the detonating line, test equipment and connecting lines; step S4, filling the interior of the preset ellipsoid test device with water, and pressurizing it to a preset hydrostatic pressure, and checking whether the test equipment works normally; step S5, detonating the preset explosion source to start the test, and collecting test data according to a preset collection time; step S6, removing unreal signals in the test data to obtain a deep-water explosion shock wave, and solving the surface load distribution of the test structure according to the deep-water explosion shock wave, wherein the unreal signals include a direct wave signal of the explosion source and a secondary reflection wave signal.

[0012] The deepwater explosion shock wave loading method based on the elliptical reflection principle of the embodiment of the present invention simulates the deep-water explosion environment based on the elliptical reflection principle, effectively reduces the impact of the shock wave reflected by the tank wall on the test structure, and improves the accuracy of the pressure tank simulated deepwater explosion damage test. At the same time, a new ellipsoidal columnar deepwater explosion pressure vessel can be constructed according to the simulated environment. The pressure vessel has the advantages of high strength, high rigidity, corrosion resistance, low noise, repeated use, and ability to simulate a large diving depth, etc., and overcomes the problem of the impact of reflected shock waves on the test that exists in existing deepwater explosion pressure vessels. In addition, it can be applied to The application areas are as follows: basic scientific research on deepwater explosions, interaction between deep-sea shock waves and cylindrical shell stress waves; simulation of deep diving to a depth within the range of human technology; analysis and exploration of the distribution law of deepwater explosion shock wave loads along cylindrical shells; conducting submarine and submersible tests to provide experimental basis and conclusions for structural explosion protection; assisting in the digital evaluation of deepwater explosion damage effects and enhancing the twin model of tests and values; underwater weapon damage power assessment; providing effective environmental conditions for simulating similarity criteria for deepwater explosion impact environment tests; and providing model tests and sites for future methane hydrate mining, bubble expansion, explosion, and marine equipment.

[0013] In addition, the deepwater explosion shock wave loading method based on the elliptical reflection principle according to the above embodiment of the present invention may also have the following additional technical features:

[0014] Furthermore, in one embodiment of the present invention, the rays emitted from the focus A position will inevitably converge at the focus B position after being reflected by the elliptical wall of the preset ellipsoid test device.

[0015] Furthermore, in one embodiment of the present invention, in step S2, the proportion of the direct wave acting on the test structure is required to be smaller than the proportion of the direct wave in the total energy of the explosion source, and then only the effect of the converged reflected wave on the test structure is considered:

[0016]

[0017] Wherein, L is the size of the test structure, F is the focal length of the ellipse in the preset ellipsoid test device, and α is the proportion of the direct wave to the total energy of the explosion source.

[0018] Furthermore, in one embodiment of the present invention, the preset acquisition time needs to meet the following conditions: when the test structure is impacted, it radiates reflected waves outward. According to the principle of elliptical reflection, the reflected waves converge at the focus A position again, and then reflect back to the focus B position for a second time. The time interval between the second reflection and the first reflection loading needs to be greater than the test time:

[0019]

[0020] Where a is the half length of the major axis of the ellipse, C is the velocity of the shock wave in water under different hydrostatic pressures, and t s It's time for testing.

[0021] Furthermore, in one embodiment of the present invention, the step S6 specifically includes: calculating the first arrival time of the direct wave of the explosion source, removing the direct wave signal of the explosion source according to the first arrival time, and leaving only the signal of the reflection field acting on the test structure; estimating the second arrival time of the secondary reflection wave signal, removing the secondary reflection signal according to the second arrival time to retain the real structural response, and obtaining the deep-water explosion shock wave.

[0022] Further, in one embodiment of the present invention, the first arrival time is:

[0023]

[0024] Among them, Δt is the first arrival time, a is the semi-length of the major axis of the ellipse, c is the focal length of the ellipse, and C is the shock wave velocity in water under different hydrostatic pressures.

[0025] Further, in one embodiment of the present invention, the second arrival time is:

[0026]

[0027] Among them, Δt2 is the second arrival time, a is the semi-length of the major axis of the ellipse, and C is the shock wave velocity in water under different hydrostatic pressures.

[0028] To achieve the above object, another embodiment of the present invention proposes a deepwater explosion shock wave loading system based on the elliptical reflection principle, including: a position determination module, used to determine the focus A position and the focus B position in a preset ellipsoid test device using the elliptical reflection principle;

[0029] A size determination module is used to determine the size of the test structure;

[0030] Arrangement module, used to set the preset explosion source at the focus A position, place the test structure at the focus B position, and arrange the detonation line, test equipment and connection lines;

[0031] A pressurizing and checking module, used to fill the interior of the preset ellipsoid test device with water and pressurize it to a preset hydrostatic pressure to check whether the test device is working properly;

[0032] A detonation and collection module, used to detonate the preset explosion source to start the test and collect test data according to a preset collection time;

[0033] The module for removing unreal signals is used to remove unreal signals in the test data, obtain deep-water explosion shock waves, and solve the surface load distribution of the test structure according to the deep-water explosion shock waves, wherein the unreal signals include direct wave signals from the explosion source and secondary reflection wave signals.

[0034] The deepwater explosion shock wave loading system based on the elliptical reflection principle of the embodiment of the present invention simulates the deep-water explosion environment based on the elliptical reflection principle, effectively reduces the impact of the shock wave reflected by the tank wall on the test structure, and improves the accuracy of the pressure tank simulated deepwater explosion damage test. At the same time, a new ellipsoidal columnar deepwater explosion pressure vessel can be constructed according to the simulated environment. The pressure vessel has the advantages of high strength, high rigidity, corrosion resistance, low noise, repeated use, and ability to simulate a large diving depth, etc., and overcomes the problem of the impact of reflected shock waves on the test that exists in existing deepwater explosion pressure vessels. In addition, it can be applied to The application areas are as follows: basic scientific research on deepwater explosions, interaction between deep-sea shock waves and cylindrical shell stress waves; simulation of deep diving to a depth within the range of human technology; analysis and exploration of the distribution law of deepwater explosion shock wave loads along cylindrical shells; conducting submarine and submersible tests to provide experimental basis and conclusions for structural explosion protection; assisting in the digital evaluation of deepwater explosion damage effects and enhancing the twin model of tests and values; underwater weapon damage power assessment; providing effective environmental conditions for simulating similarity criteria for deepwater explosion impact environment tests; and providing model tests and sites for future methane hydrate mining, bubble expansion, explosion, and marine equipment.

[0035] In another aspect, an embodiment of the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the deep-water explosion shock wave loading method based on the elliptical reflection principle as described in the above embodiment is implemented.

[0036] In another aspect, an embodiment of the present invention provides a non-temporary computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the deep-water explosion shock wave loading method based on the elliptical reflection principle as described in the above embodiment.

[0037] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0039] Figure 1 It is a flow chart of a deep-water explosion shock wave loading method based on the elliptical reflection principle according to one embodiment of the present invention;

[0040] Figure 2 is a schematic diagram of an elliptical cylinder tank device according to an embodiment of the present invention;

[0041] Figure 3 A schematic diagram of the elliptical reflection principle according to an embodiment of the present invention;

[0042] Figure 4 is a diagram showing the relationship between the size of a test structure and the focal length of an ellipse according to an embodiment of the present invention;

[0043] Figure 5 is a schematic diagram of elliptical reflected energy flux density according to an embodiment of the present invention;

[0044] Figure 6 is a schematic diagram of a three-compartment model according to an embodiment of the present invention;

[0045] Figure 7 A test principle diagram according to an embodiment of the present invention;

[0046] Figure 8 The figure is a schematic structural diagram of a deep-water explosion shock wave loading system based on the elliptical reflection principle according to an embodiment of the present invention. DETAILED DESCRIPTION

[0047] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0048] The following describes a deepwater explosion shock wave loading method and system based on the elliptical reflection principle proposed in accordance with an embodiment of the present invention with reference to the accompanying drawings. First, the deepwater explosion shock wave loading method based on the elliptical reflection principle proposed in accordance with an embodiment of the present invention will be described with reference to the accompanying drawings.

[0049] Figure 1 The present invention is a flowchart of a deep-water explosion shock wave loading method based on the elliptical reflection principle according to an embodiment of the present invention.

[0050] like Figure 1 As shown, the deep-water explosion shock wave loading method based on the elliptical reflection principle includes the following steps:

[0051] In step S1, the positions of focus A and focus B in a preset ellipsoid test device are determined using the elliptical reflection principle.

[0052] It should be noted that if Figure 2As shown, the preset ellipsoid test device is an elliptical cylinder pressure vessel, whose shell is made of high-strength steel, the internal space is an ellipsoid cylinder, the shell is reinforced on the outside to ensure the structural strength, the shell is connected to the foundation through a vibration-damping base, and lighting windows and observation windows are provided at appropriate positions of the shell. Light is irradiated into the interior of the shell through the lighting window, and the internal test process is filmed through the observation window with a high-speed camera. A hatch is provided on the top of the shell, which can be opened to place the test structure and the explosion source, and a wire threading pipeline is reserved in the shell to facilitate the passage of the test wire.

[0053] Furthermore, it is necessary to carry out structural design of the preset ellipsoid test device, which mainly includes six aspects: shell structure design requirements, hydrostatic pressure, incident overpressure peak, reflected overpressure peak, equivalent static load design and shell wall thickness design.

[0054] (1) Shell structure design requirements: 1) Meet the TNT equivalent of the explosion source; 2) The length and inner diameter of the container should meet the manual operation space; 3) The container can be reused for a long time; 4) Pressurization; 5) Functional requirements: a. Column: The main structure consists of ribbed elliptical column segments and upper heads; b. Vibration isolation; c. Sound insulation.

[0055] (2) Hydrostatic pressure

[0056] In China, water is pressurized by pressure tanks to create a high hydrostatic pressure test environment. In order to simulate deep water pressure, the hydrostatic pressure P0 is:

[0057] P0=P atm +ρgh (1)

[0058] Where P atm is the standard atmospheric pressure, ρ is the density of water, g is the acceleration due to gravity, and h is the water depth.

[0059] (3) Peak incident overpressure

[0060] Empirical formula for calculating overpressure caused by underwater explosion shock wave:

[0061]

[0062] Where W is the charge, in kg; R is the distance from the explosion center to the observation point, in m; R0 is the initial radius of the charge, in m; P m is the peak pressure, in Pa; θ is the shock wave time decay constant, in s; t p is the time of positive pressure action of shock wave, in seconds.

[0063] (4) Reflection overpressure peak

[0064] Empirical formula for calculating the overpressure of underwater explosion shock wave reflection:

[0065]

[0066] (5) Equivalent static load design

[0067] 1) Calculate the power coefficient P r

[0068] With reference to the articles "Engineering Design Method and Application of Explosion Container" and "Explosion Container", the dynamic coefficient of the container design is determined according to a method for engineering design of explosion container based on structural mechanics theory - dynamic coefficient method.

[0069] Water explosion shock wave pulse width:

[0070]

[0071] P r is the dynamic load coefficient, and its value is related to the time-varying characteristics of pressure, the duration of pressure action and the natural frequency of the shell.

[0072]

[0073] Where τ is the pulse width of the shock wave, ω=2π / T0, and T0 is the natural oscillation period.

[0074] The calculation formula of the natural vibration period of cylindrical shell is:

[0075]

[0076] μ = 0.3 is Poisson's ratio, E = 206 GPa is Young's modulus, ρ = 7850 kg / m 3 is the shell material density, and R is the shell plate frame.

[0077] 2) Calculate the equivalent static load

[0078] Equivalent static load P of the container e Calculation formula:

[0079] P c =P r ΔP2 (7)

[0080] P e =1.2P c (8)

[0081] According to GB150, the safety factor is 1.2. That is, the main strength of the explosion container shell is P e Pressure design.

[0082] (6) Shell wall thickness design

[0083] 1) Calculate wall thickness δ

[0084] The strength design is carried out according to the relevant standards of GB150-1998 "Steel Pressure Vessels". The calculated wall thickness of the designed cylinder is calculated according to formula (9). The formula is applicable to P e ≤0.4[σ] t φ, take the design load as P e .

[0085]

[0086] Where, δ is the calculated thickness of the container cylinder, in mm; D is the inner diameter of the cylinder, D = 12000 mm; φ is the welding joint coefficient, φ = 1.0; P e To calculate the pressure; [σ] t is the allowable stress of the material.

[0087] 2) Design wall thickness δ d

[0088] The design thickness of the container cylinder is calculated according to formula (10):

[0089] δ d =δ+C1+C2+C3 (10)

[0090] In the formula, δ d is the designed wall thickness of the container, in mm; δ is the calculated wall thickness of the container, in mm; C1 is the negative deviation of steel thickness, taking C1 = 0.25 mm; C2 is the corrosion allowance, taking C2 = 1 mm; C1 is the process thinning amount, taking C3 = δ n ×10%,δ n The above parameters are selected with reference to GB150-1998 "Steel Pressure Vessels".

[0091] Furthermore, if Figure 3 As shown, the positions of focus A and focus B in the preset ellipsoid test device are determined by using the following two characteristics of the elliptical reflection principle:

[0092] Characteristic 1: According to the ellipse reflection principle, the rays emitted from one focus of the ellipse (focus A) will inevitably converge at the other focus of the ellipse (focus B) after being reflected by the ellipse wall. If the explosion source is set at the focus A of the ellipse, then its explosion shock wave will inevitably converge at the focus B after passing through the ellipse to avoid reflection. If the test structure is placed at the focus B, it will be subjected to the reflected wave load that converges to the center.

[0093] Feature 2: If the shock wave emitted by focus A is isotropic, then the reflected shock wave it receives at focus B is non-uniform, with the shock wave being stronger on the side facing A and weaker on the side facing away from A.

[0094] The principle of elliptical reflection is fully utilized to form a shock wave with non-uniform distribution along the circumference and superimpose it with the deep-water static pressure to simulate different shock wave loads.

[0095] The shock wave generated at the focus of the explosion source is distributed in the same direction as the compression wave at another focus along the cylindrical shell. The loads on the front and rear surfaces are slightly different. This feature is completely consistent with the shock wave load characteristics of the surface explosion of deep-water explosive structures.

[0096] In step S2, the dimensions of the test structure are determined.

[0097] Specifically, Figure 4 As shown, the test structure needs to be small enough so that the effect of the direct wave from the explosion source on the structure can be ignored, and only the effect of the convergent reflected wave on the structure can be examined.

[0098] The proportion of the direct wave acting on the structure is smaller than the proportion of the direct wave in the total energy of the explosion source, and can be ignored:

[0099]

[0100] Wherein, L is the size of the test structure, F is the focal length of the ellipse in the preset ellipsoid test device, and α is the proportion of the direct wave to the total energy of the explosion source.

[0101] In step S3, the preset explosive source is set at the focus A position, the test structure is placed at the focus B position, and the detonating wire, test equipment and connecting lines are arranged.

[0102] In step S4, the interior of the preset ellipsoid test device is filled with water and pressurized to a preset hydrostatic pressure to check whether the test device works normally.

[0103] In step S5, the preset explosion source is detonated to start the test, and the test data is collected according to the preset collection time.

[0104] Specifically, after the test structure is impacted, it will radiate reflected waves outward. According to the principle of elliptical reflection, this reflected wave will converge at focus A again, and then reflect back to focus B (where the test structure is located) for a second time. This part of the secondary reflection is an incorrect reflection. Therefore, the time interval between the secondary reflection and the first reflection loading needs to be greater than the test time to avoid affecting the test.

[0105] The time interval between the second reflection and the first reflection loading (i.e. the preset acquisition time) needs to be greater than the test time:

[0106]

[0107] Where a is the half length of the major axis of the ellipse, C is the velocity of the shock wave in water under different hydrostatic pressures, and t s It's time for testing.

[0108] In step S6, the unreal signals in the test data are removed to obtain the deepwater explosion shock wave, and the surface load distribution of the test structure is solved according to the deepwater explosion shock wave, wherein the unreal signals include the direct wave signal of the explosion source and the secondary reflection wave signal.

[0109] Specifically, after obtaining the test data, it is necessary to remove the direct wave signal and the secondary reflection wave signal of the explosion source through signal processing means, as follows:

[0110] (1) Processing of direct wave signals from the explosion source

[0111] Although the direct wave from the explosion source accounts for a small proportion, it will also affect the impulse response signal. It is necessary to remove it from the signal. Because the direct wave will arrive earlier than the reflected wave, the first arrival time of the direct wave from the explosion source is calculated. The direct wave signal from the explosion source is removed according to the first arrival time, leaving only the signal of the reflected field acting on the test structure. The time interval is:

[0112]

[0113] Among them, Δt is the first arrival time, a is the semi-length of the major axis of the ellipse, c is the focal length of the ellipse, and C is the shock wave velocity in water under different hydrostatic pressures.

[0114] (2) Secondary reflection wave signal processing

[0115] Estimate the second arrival time of the secondary reflection wave signal, remove the secondary reflection signal according to the second arrival time to retain the real structural response, and obtain the deep-water explosion shock wave, where the second arrival time is:

[0116]

[0117] Among them, Δt2 is the second arrival time, a is the semi-length of the major axis of the ellipse, and C is the shock wave velocity in water under different hydrostatic pressures.

[0118] Furthermore, the process of solving the surface load distribution of the test structure according to the deep-water explosion shock wave is as follows:

[0119] like Figure 5 As shown, according to the aforementioned elliptical reflection principle, the shock wave energy flux density at the transmitting end (focus A) is recorded as:

[0120] Q(β)=Q0,β∈[0,π](15)

[0121] The energy flux density at the receiving end (focus B) is:

[0122] Q(θ),θ∈[0,π](16)

[0123] Assume that at the receiving end (focus B) θ, the energy within the range of Δθ is:

[0124] The energy flux density is:

[0125]

[0126] Establish the functional relationship between the transmitting end β (focus A) and the receiving end θ (focus B), that is,

[0127] β=f(θ)(18)

[0128] The energy of the explosion source in [θ,θ+Δθ] is the same as the energy in [β,β1], then: β=f(θ), β1=f(θ+Δθ), therefore,

[0129]

[0130] like Figure 4 As shown, the relationship between β and θ is established based on the properties of the ellipse:

[0131]

[0132] In the formula, 2a is the major axis length of the ellipse, and 2c is the focal length of the ellipse;

[0133] The derivation process of the formula is as follows:

[0134] According to formula (20), we can get:

[0135]

[0136]

[0137]

[0138] Combining equations (17), (19), and (23), we can get:

[0139]

[0140]

[0141] After the explosive explodes underwater, the shock wave overpressure quickly reaches its maximum value, and then decays exponentially to the hydrostatic pressure, as shown in the formula:

[0142] p(t)=p m ·exp(-t / ψ)(26)

[0143] Where p(t) is the relationship between the shock wave overpressure and time, unit: MPa; p m is the peak value of the shock wave overpressure, in MPa; ψ is the time constant, the shock wave pressure changes from the peak pressure p m Decay to The time elapsed.

[0144] Among them, p m Calculated according to the empirical formula of underwater explosion shock wave incident overpressure:

[0145]

[0146] The effective shock wave energy produced by unit mass of explosives is:

[0147]

[0148] Where R is the distance between the explosive and the explosion center, in meters; W is the charge of the explosive, in kilograms; ρ0 is the density of water, in kilograms / m 3 ; S is the charge surface area, unit: m 2 ; c0 is the speed of sound in water, unit: m / s; E s It is the effective shock wave energy, in J / Kg.

[0149] Explosion energy flux (density):

[0150]

[0151] In the formula, φ E is the energy flux (density), unit J / m 2 ; S is the charge surface area, unit: m 2 .

[0152] Explosion power flux (energy flux density):

[0153]

[0154] In the formula, φ P is the power flux (energy density), unit is W / m 2 ; S is the charge surface area, unit: m 2 ,T is the explosion action time, 6.7ψ;

[0155] By combining formulas (28), (29) and (30), we can get the energy flux density at the focus A, i.e. the detonation point, as follows:

[0156]

[0157] That is, Q(β)=Q0=φ P ;

[0158] Combining formula (31), we can get:

[0159]

[0160] Simultaneous formula (26)(27)(32)

[0161]

[0162] That is, when the explosive is detonated at the focus A of the elliptical test device, the energy flux density on the structure placed at the focus B is Q(θ).

[0163] Where ρ0 is the density of water, in kg / m 3 ; c0 is the speed of sound in water, unit is m / s; ψ is the time constant, the shock wave pressure changes from the peak pressure p m Decay to The time elapsed, unit is s; θ∈[0,π]; 2a is the length of the major axis of the ellipse; 2c is the focal length of the ellipse; t is the explosion time, unit is s; r is the radius of the explosive, unit is m; R is the explosion distance, unit is m.

[0164]

[0165] Where ρ0 is the density of water, in kg / m 3 ; c0 is the speed of sound in water, unit is m / s; P θ is the distribution of pressure on the structure surface at focus B.

[0166] The deep-water explosion shock wave loading method based on the elliptical reflection principle proposed in the embodiment of the present invention is further described below through a specific embodiment.

[0167] Step 1: Design the structural dimensions of the elliptical test device.

[0168] Assume that the loaded test model is a cylindrical cabin model with a length of 2m and an outer diameter of 1.2m.

[0169] like Figure 6 As shown, according to formula (11), we can get:

[0170]

[0171] Where, α≤2%, L is the size of the test structure 1.2m, and F=2c is the focal length of the ellipse;

[0172] The solution is: F ≥ 9.53m, that is, the focal length of the ellipse c ≥ 4.765m.

[0173] According to formula (12), we can get:

[0174]

[0175] Where a is the half length of the major axis of the ellipse, C is the velocity of the shock wave in water under different hydrostatic pressures, C = 1480 m / s, t s is the test time, t s =15ms;

[0176] The solution is: a≥5.55m, that is, the focal length of the ellipse a≥5.55m.

[0177] Therefore, the minor axis length of the elliptical test device is The major axis length is 12m, the focal length is 10m and the width is 8m.

[0178] Step 2: Design the wall thickness of the elliptical test device

[0179] According to the empirical formula (2) for calculating the incident overpressure of underwater explosion shock waves, the incident overpressure is solved as:

[0180]

[0181] According to the empirical formula (3) for calculating the reflected overpressure of underwater explosion shock waves, the reflected overpressure is calculated as:

[0182]

[0183] To design the equivalent static load, first calculate the dynamic coefficient Pr, and then calculate the equivalent static load through the dynamic coefficient Pr, as follows:

[0184] According to "Engineering Design Method and Application of Explosion Container" and "Explosion Container", a method for engineering design of explosion container based on structural mechanics theory - dynamic coefficient method is used to determine the dynamic coefficient of the container design.

[0185] The pulse width of the water explosion shock wave is calculated according to formula (4):

[0186]

[0187] The self-array period of the cylindrical shell is calculated according to formula (6):

[0188]

[0189] ω=2π / T0=853.69rad / s

[0190] According to formula (5), the dynamic load coefficient P r for:

[0191]

[0192] Calculate the equivalent static load of the container according to formulas (7) and (8):

[0193] P c =P r ΔP2=0.048×9.01=0.43MPa

[0194] P e =1.2P c =0.52Mpa

[0195] According to GB150, the safety factor is 1.2. That is, the main strength of the explosion container shell is P e Pressure design.

[0196] Step 3: Design the design thickness δ of the container cylinder d .

[0197] The strength design is carried out according to the relevant standards of GB150-1998 "Steel Pressure Vessels". The wall thickness of the cylinder is calculated according to formula (9). The formula is applicable to P e ≤0.4[σ] t φ=68MPa, take the design load P e =0.52MPa.

[0198]

[0199] Where, δ is the calculated thickness of the container cylinder, in mm; D is the inner diameter of the cylinder, D = 12000 mm; φ is the welding joint coefficient, φ = 1.0; P c To calculate the pressure, take P c =1.404MPa; [σ] t is the allowable stress of the material, and the allowable stress of 907 steel is taken as 170MPa.

[0200] The design wall thickness of the elliptical test device cylinder is calculated according to formula (10):

[0201] δ d =δ+C1+C2+C3=21.65mm

[0202] In the formula, δ d is the designed wall thickness of the container, in mm; δ is the calculated wall thickness of the container, which is 18.4 mm; C1 is the negative deviation of the steel thickness, which is C1 = 0.25 mm; C2 is the corrosion allowance, which is C2 = 1 mm; C1 is the process thinning amount, which is C3 = δ n ×10%,δ n is the nominal thickness of the container, which is 20 mm.

[0203] Therefore, the shell thickness of the elliptical test device is 22 mm, and reinforcement is added outside the elliptical test device to increase strength.

[0204] Step 4: Figure 7 As shown, the test process is recorded by high-speed video, and the acceleration of the cabin is measured by acceleration sensors to analyze the impact environment. The load is measured by pressure sensors to analyze the load characteristics. The plastic strain of the structure is measured by strain gauges. Through 3D scanning technology and post-investigation measurements, the post-test breach size, deformation and other parameters are obtained to analyze the damage mode and verify the damage mode judgment criteria.

[0205] In summary, the deepwater explosion shock wave loading method based on the elliptical reflection principle proposed in the embodiment of the present invention simulates the deep-water explosion environment based on the elliptical reflection principle, solves the problem that the superposition of the existing reflected wave and the incident shock wave seriously changes the shock wave load characteristics of the front explosion surface and the back explosion surface under the actual deepwater explosion, thereby causing a large difference between the prototype and the model, and the simulation result cannot be converted into the actual result at all, and effectively reduces the influence of the shock wave reflected by the tank wall on the test structure, and improves the accuracy of the pressure tank simulated deepwater explosion damage test; in addition, a new ellipsoidal column deepwater explosion pressure vessel can be constructed according to the simulated explosion environment. Compared with the traditional spherical tank-shaped container, the pressure vessel is set to an ellipsoidal column shape, so that it is easy to install and fix, and the simulated deepwater environment explosion experiment can be carried out on any horizontal ground. The pressure vessel has the advantages of high strength, high rigidity, corrosion resistance, low noise, repeated use, and can simulate a large diving depth, etc., and overcomes the problem of the influence of reflected shock waves on the test that exists in the existing deepwater explosion pressure vessels.

[0206] Next, a deep-water explosion shock wave loading system based on the elliptical reflection principle proposed in an embodiment of the present invention will be described with reference to the accompanying drawings.

[0207] Figure 8 It is a structural schematic diagram of a deep-water explosion shock wave loading system based on the elliptical reflection principle according to an embodiment of the present invention.

[0208] like Figure 8 As shown, the system 10 includes: a position determination module 100 , a size determination module 200 , a placement module 300 , a pressurization and inspection module 400 , a detonation and collection module 500 , and a false signal removal module 600 .

[0209] Among them, the position determination module 100 is used to determine the focus A position and the focus B position in the preset ellipsoid test device by using the elliptical reflection principle. The size determination module 200 is used to determine the size of the test structure. The layout module 300 is used to set the preset explosion source at the focus A position, place the test structure at the focus B position, and arrange the detonation line, test equipment and connections. The pressurization and inspection module 400 is used to fill the interior of the preset ellipsoid test device with water, and pressurize it to the preset hydrostatic pressure to check whether the test equipment is working properly. The detonation and acquisition module 500 is used to detonate the preset explosion source to start the test, and collect test data according to the preset acquisition time. The unreal signal removal module 600 is used to remove unreal signals in the test data, obtain the deep-water explosion shock wave, and solve the surface load distribution of the test structure according to the deep-water explosion shock wave, wherein the unreal signal includes the explosion source direct wave signal and the secondary reflection wave signal.

[0210] It should be noted that the aforementioned explanation of the embodiment of the deep-water explosion shock wave loading method based on the elliptical reflection principle is also applicable to the system of this embodiment and will not be repeated here.

[0211] According to the deepwater explosion shock wave loading system based on the elliptical reflection principle proposed in the embodiment of the present invention, the deepwater explosion environment is simulated based on the elliptical reflection principle, and the problem that the superposition of the existing reflected wave and the incident shock wave seriously changes the shock wave load characteristics of the front explosion surface and the back explosion surface under the actual deepwater explosion situation is solved, which leads to a large difference between the prototype and the model, and the simulation result cannot be converted into the actual result at all. It effectively reduces the influence of the shock wave reflected by the tank wall on the test structure, and improves the accuracy of the pressure tank simulated deepwater explosion damage test; in addition, a new ellipsoidal column deepwater explosion pressure vessel can be constructed according to the simulated explosion environment. Compared with the traditional spherical tank-shaped vessel, the pressure vessel is set to an ellipsoidal column shape, so that it is easy to install and fix, and the simulated deepwater environment explosion experiment can be carried out on any horizontal ground. At the same time, the pressure vessel has the advantages of high strength, high rigidity, corrosion resistance, low noise, repeated use, and the ability to simulate a large diving depth, etc., and overcomes the problem of the influence of the reflected shock wave on the test existing in the existing deepwater explosion pressure vessels.

[0212] In order to implement the above embodiments, the present invention also proposes an air-conditioning device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the deep-water explosion shock wave loading method based on the elliptical reflection principle as described in the above embodiments is implemented.

[0213] In order to implement the above embodiments, the present invention also proposes a non-temporary computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the deep-water explosion shock wave loading method based on the elliptical reflection principle as described in the above embodiments is implemented.

[0214] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0215] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "N" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0216] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0217] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or N wirings (electronic devices), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0218] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0219] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0220] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0221] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A deepwater explosion shock wave loading method based on the elliptical reflection principle, characterized in that: The following steps are involved: Step S1, using the elliptical reflection principle to determine the focus A position and the focus B position in a preset ellipsoid test device; Step S2, determining the size of the test structure; Step S3, setting a preset explosion source at the focus A position, placing the test structure at the focus B position, and arranging the detonation cord, test equipment and connection lines; Step S4, filling the interior of the preset ellipsoid test device with water and pressurizing it to a preset hydrostatic pressure, and checking whether the test device works normally; Step S5, detonating the preset explosion source to start the test, and collecting test data according to a preset collection time; Step S6, removing the unreal signals in the test data, obtaining the deep-water explosion shock wave, and solving the surface load distribution of the test structure according to the deep-water explosion shock wave, wherein the unreal signals include the explosion source direct wave signal and the secondary reflection wave signal.

2. The deep-water explosion shock wave loading method based on the elliptical reflection principle according to claim 1 is characterized in that: The rays emitted from the focus A position will inevitably converge at the focus B position after being reflected by the elliptical wall of the preset ellipsoid test device.

3. The deep-water explosion shock wave loading method based on the elliptical reflection principle according to claim 1 is characterized in that: In step S2, the proportion of direct waves acting on the test structure needs to be smaller than the proportion of direct waves in the total energy of the explosion source, and only the effect of the converged reflected waves on the test structure is considered: Wherein, L is the size of the test structure, F is the focal length of the ellipse in the preset ellipsoid test device, and α is the proportion of the direct wave to the total energy of the explosion source.

4. The deep-water explosion shock wave loading method based on the elliptical reflection principle according to claim 1 is characterized in that: The preset collection time must meet the following conditions: When the test structure is impacted, it radiates reflected waves outward. According to the principle of elliptical reflection, the reflected waves converge at the focus A again, and then reflect back to the focus B for a second time. The time interval between the second reflection and the first reflection loading needs to be greater than the test time: Where a is the half length of the major axis of the ellipse, C is the velocity of the shock wave in water under different hydrostatic pressures, and t s It's time for testing.

5. The deep-water explosion shock wave loading method based on the elliptical reflection principle according to claim 1 is characterized in that: The step S6 specifically includes: Calculating a first arrival time of a direct wave from an explosion source, and removing the direct wave signal from the explosion source according to the first arrival time, leaving only a signal of the reflected field acting on the test structure; The second arrival time of the secondary reflection wave signal is estimated, and the secondary reflection signal is removed according to the second arrival time to retain the real structural response, thereby obtaining the deep-water explosion shock wave.

6. The deep-water explosion shock wave loading method based on the elliptical reflection principle according to claim 5 is characterized in that: The first arrival time is: Among them, Δt is the first arrival time, a is the semi-length of the major axis of the ellipse, c is the focal length of the ellipse, and C is the shock wave velocity in water under different hydrostatic pressures.

7. The deep-water explosion shock wave loading method based on the elliptical reflection principle according to claim 5 is characterized in that: The second arrival time is: Among them, Δt2 is the second arrival time, a is the semi-length of the major axis of the ellipse, and C is the shock wave velocity in water under different hydrostatic pressures.

8. A deepwater explosion shock wave loading system based on the elliptical reflection principle, characterized in that: include: A position determination module is used to determine the position of focus A and focus B in a preset ellipsoid test device by using the elliptical reflection principle; A size determination module is used to determine the size of the test structure; Arrangement module, used to set the preset explosion source at the focus A position, place the test structure at the focus B position, and arrange the detonation line, test equipment and connection lines; A pressurizing and checking module, used to fill the interior of the preset ellipsoid test device with water and pressurize it to a preset hydrostatic pressure to check whether the test device is working properly; A detonation and collection module, used to detonate the preset explosion source to start the test and collect test data according to a preset collection time; The module for removing unreal signals is used to remove unreal signals in the test data, obtain deep-water explosion shock waves, and solve the surface load distribution of the test structure according to the deep-water explosion shock waves, wherein the unreal signals include direct wave signals from the explosion source and secondary reflection wave signals.

9. A computer device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for loading deep-water explosion shock waves based on the elliptical reflection principle as described in any one of claims 1 to 7 is implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the deep-water explosion shock wave loading method based on the elliptical reflection principle as described in any one of claims 1 to 7 is implemented.

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