Submarine structure deepwater explosion simulation equivalent test device and method based on stress wave principle

Abstract

The invention belongs to the technical field of submarine equivalent pressurization test for simulating a deepwater environment, and particularly relates to a submarine structure deepwater explosion simulation equivalent test device and method based on a stress wave principle, which can simulate hydrostatic pressure of a submarine model in a deepwater area. The test device comprises a water pool, an explosion source and a test device, the testing device is arranged in the water tank, and an explosion source is arranged on one side of the testing device; the testing device comprises a pressurizing cover and a target model arranged in the pressurizing cover. A water outlet is formed in the bottom end of the pressurizing cover; the quality of the explosion source and the distance between the explosion source and the testing device meet the testing requirements of the testing device after scaling. The device can accurately simulate the hydrostatic pressure in a deepwater combat environment, the pressurization cover simulates the hydrostatic pressure in deepwater by adding water pressure, key test factors such as insufficient water depth of a pool in an underwater explosion test can be solved, a test device can be manually hoisted for operation, the pressurization operation of a water inlet and a water outlet is convenient, and the test efficiency is improved. And the convenience is realized.

Description

Technical Field

[0001] The invention relates to the technical field of deepwater submarine equivalent test device design, and in particular to a deepwater explosion simulation equivalent test device and method for submarine structures based on stress wave principle. Background Art

[0002] All countries attach great importance to research on improving the explosion resistance and shock resistance of surface ships and underwater submarines and have conducted a large number of actual ship explosion experiments, accumulating a large amount of valuable data. However, my country has conducted relatively few underwater explosion experiments, especially explosion experiments on underwater submarines, which are even rarer. This has limited the improvement of the explosion resistance and shock resistance design capabilities of ships and submarines to a certain extent.

[0003] To simulate the deepwater explosion effect near an actual submarine in a conventional explosion pool, it is necessary to simulate the hydrostatic pressure to a certain extent. Usually, in order to study the damage of deepwater explosion to submarine structures, it is necessary to pressurize the surface of the structure. The existing experimental method is to conduct it in a pressurized container, but this limits the size of the model and increases the difficulty of the experiment. To this end, according to the equivalent loading principle in stress wave theory, water is injected between the double hulls of the submarine to increase pressure, which well realizes the deepwater explosion experiment in natural waters. Therefore, proposing a complete design scheme for the equivalent test device for deepwater explosion submarine structure damage is a problem that needs to be solved in the field of deepwater explosion structural response. Summary of the invention

[0004] In response to the technical problems mentioned in the background technology, the present invention proposes a complete design scheme for a deep-water explosion submarine structural damage equivalent test device. By giving parameters such as the test water depth, similar scale size, explosion load characteristics, etc. required in the explosion test, the specific design scheme for each part of the scheme is proposed.

[0005] The invention provides a submarine structure deep-water explosion simulation equivalent test device based on stress wave principle, comprising a water pool, an explosion source, and a test device; the test device is arranged inside the water pool, and an explosion source is provided on one side of the test device; the test device comprises a pressure cover and a target model; the target model is arranged inside the pressure cover; a water injection port is provided at the top end of the pressure cover, and a water outlet is provided at the bottom end; the target model comprises a pressure hull; the radius of the explosion source, the mass of the explosion source, and the distance between the explosion source and the test device meet the test requirements of the test device after reduction.

[0006] Furthermore, the target model and the front and rear ends of the pressurized cover are sealed by a sealing plate, and a test cable port is provided on the sealing plate; a sealing valve is installed at the water injection port, and a pressure gauge is arranged on the valve.

[0007] Furthermore, the radius of the explosion source and the reduction ratio of the target model are designed to meet the reduction ratio β; the mass of the explosion source and the reduction ratio of the target model are designed to meet the reduction ratio β 3 The explosion source mass W and the distance R between the explosion source and the test device meet the new explosion impact factor C of the target structural characteristics of the test device:

[0008]

[0009] Furthermore, the simulated explosion impact factor C is the same as the original explosion impact factor C.

[0010] Furthermore, the distance d between the target model and the pressure cover is designed according to the distance R between the pressure cover of the test device and the explosion source and the mass W of the explosion source:

[0011]

[0012] Where θ is the time decay constant.

[0013] Furthermore, the distance R between the pressure cover and the explosion source and the explosion source radius r are determined according to the peak pressure P required by the test. m To design, the following relationship is satisfied:

[0014]

[0015] Where l and k are test coefficients; α and β are impact pressure attenuation coefficients.

[0016] Furthermore, the 1 / 2 circumference a of the pressure cover, the distance b between the two ends of the pressure cover, and the thickness h of the pressure cover are determined according to the strength Q of the pressure cover required by the experiment. p To design, the following relationship is satisfied:

[0017]

[0018] In the formula, σ s is the ultimate tensile strength of the material.

[0019] The present invention further provides a test method for a submarine structure deep-water explosion simulation equivalent test device based on the stress wave principle, comprising the following steps:

[0020] Step 1: Calculate the material, thickness and size of the pressure cover according to the load size and target size required for the test, and prepare the pressure cover;

[0021] Step 2: Weld the target model and the pressure cover into an integrated structure as a test model, and install lifting ears on the surface of the test model;

[0022] Step 3: Arrange sensors in the target model and check the water tightness of the test model and the effectiveness of the test cable port;

[0023] Step 4: Inject water from the water injection port of the pressurized cover. When the water fills the interlayer space between the pressurized cover and the target model, stop injecting water. Install a one-way sealing valve on the water injection port. Continue to inject water into the water injection port through the one-way valve to increase the pressure until the pressure gauge on the valve reaches the set pressure.

[0024] Step 5: Place the test device into different water depths through the lifting lugs, arrange the explosion source on one side of the test device, and test the impact acceleration response, elastic-plastic strain signal, and target shell deflection of the target model.

[0025] Furthermore, in step 4, the pressure value P is set on the pressure gauge:

[0026]

[0027] Where, P is the set pressure value of the pressure gauge, MPa; H is the simulated water depth of the test device, m.

[0028] Furthermore, in step 5, the deflection of the target shell is selected in the maximum plastic deformation area, which is the vertical distance of the measuring point position concave to the center of the circle.

[0029] The beneficial effects of the present invention are:

[0030] (1) In the absence of relevant design standards, the present invention provides a design method for a pressure hood integrated with a target structure to address the technical and ease-of-use issues that exist during deepwater explosion tests.

[0031] (2) The present invention proposes design requirements and methods for the thickness of the pressure hood and the spacing between the pressure hood and the side of the pressure hood based on the characteristics of deep-water explosion loads and the transmission and reflection principles of shock waves.

[0032] (3) The present invention solves the problem of wall reflection of shock waves in the explosion water tank interfering with test data. The scheme can carry out pressurized explosion tests in the water tank. The pressurized cover is made of high-strength steel, which can carry out multiple tests at one time, saving time and labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the principle of the deep-water explosion submarine structural damage equivalent test device, in which: 1-pressurization cover, 2-target, 3-explosion source, 4-explosion pool, 5-pressurized water;

[0034] Figure 2 The figure is a view of the deep-water explosion submarine structural damage equivalent test device, where (a) is a two-dimensional front view and (b) is a side view;

[0035] Figure 3This is a diagram of the equivalent test device for deep-water explosion submarine structure damage, in which: 1-pressurized shell, 2-test cable port, 3-water injection port, 4-upper lifting lug, 5-lower lifting lug, 6-bulkhead, 7-sealing plate, 8-watertight door;

[0036] Figure 4 It is a schematic diagram of shock wave transmission based on the stress wave principle of the deep-water explosion submarine structural damage equivalent test device;

[0037] Figure 5 The dimensions of the pressure cover of the deep-water explosion submarine structural damage equivalent test device;

[0038] Figure 6 This is a side view of the deformation deflection measurement position of the deep-water explosion submarine structure damage equivalent test device. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with the accompanying drawings.

[0040] The design scheme of the deepwater explosion submarine structural damage equivalent test device proposed in the present invention includes the design of a prototype target scaled target model, a pressure cover design, a water inlet and outlet design, a load-bearing device, etc. The target target is welded to the pressure cover, and the water inlet and outlet are welded to the load-bearing device at a fixed position of the pressure cover. The welding sequence is target target-pressure cover-water inlet and outlet-load-bearing device. The present invention has a deepwater equivalent pressurization function and can simulate a deepwater environment in conventional depth waters; since the depth of the explosion pool for the test is limited, it is necessary to simulate the hydrostatic pressure in deep water by increasing the water pressure outside the target target; a layer of pressure cover is designed on the outer layer of the target target to add water between the sides, and compress the water medium between the sides to increase the pressure on the target target.

[0041] The present invention discloses a submarine structure deep-water explosion simulation equivalent test device based on stress wave principle, including a water pool, an explosion source, and a test device; the test device is arranged inside the water pool, and an explosion source is provided on one side of the test device; the test device includes a pressure cover and a target model; the target model is arranged inside the pressure cover; a water injection port is provided at the top of the pressure cover, and a water outlet is provided at the bottom; the target model includes a pressure hull; the radius of the explosion source, the mass of the explosion source, and the distance between the explosion source and the test device meet the test requirements of the test device after scaling. The radius of the explosion source and the size scaling ratio of the target model are both β; the mass scaling ratio of the explosion source is β 3 The explosion source mass W and the distance R between the explosion source and the test device meet the new explosion impact factor C of the target structural characteristics of the test device:

[0042]

[0043] (1) Working principle of the pressure shield based on the transmission of stress waves at the medium interface

[0044] When a shock wave propagates in different media, due to the differences in physical quantities such as density, impedance and compression modulus of different media, reflected and transmitted shock waves will be generated at the interface between the media. The reflected wave will return in the original direction, while the transmitted wave will continue to propagate in the new direction. At the same time, rarefaction waves will also be generated at the interface. This is a phenomenon in which the shock wave attenuates and strengthens alternately due to changes in the density of the medium. Transreflection when the shock wave couples with the underwater structure can be divided into two cases:

[0045] When the shock wave propagates from the water medium to the steel medium, n<1, that is, ρ1c1<ρ2c2, then 1<R t <2,R r >0; where medium 1 is water and medium 2 is steel, it means that when the shock wave is incident from a low impedance medium to a high impedance medium, the reflected wave is a sparse wave, which will cause pressure unloading when superimposed with the incident wave, and the peak value of the transmitted wave is stronger than the peak value of the incident wave. When the shock wave propagates from the steel medium to the water medium, n>1, that is, ρ1c1>ρ2c2, then 0<R t <1, R r <0; where medium 1 is steel and medium 2 is water, it means that when the shock wave is incident from a high impedance medium to a low impedance medium, the reflected wave is a compression wave. The compression wave and the incident shock wave will increase the pressure after being superimposed, while the peak value of the transmitted wave is lower than the peak value of the incident wave. The reflection coefficient R can be equal to zero, less than zero, or greater than zero.

[0046] Assume that a one-dimensional elastic wave propagates from one medium 1 to another medium 2, and the interface between the mediums is A-A, such as Figure 4 As shown, the peak value of the reflected stress wave σ r , peak value of transmitted stress wave σ t and the incident stress wave peak σ i The relationship between them is:

[0047] σ r =R r σ i

[0048] σ t =R t σ i

[0049]

[0050]

[0051] In the formula, R r is the vertical reflection coefficient of stress wave; R t is the vertical transmission coefficient of stress wave;

[0052] It can be seen from the above formula that when the shock wave is incident vertically, the magnitude of the reflected stress wave and the transmitted stress wave is a function of the ratio of the incident medium impedance to the projected medium impedance.

[0053] (2) Design of the distance d between the pressure shield and the target model taking into account the thickness of the wave head

[0054] The model test design criteria point out that the design of the spacing between the model pressure shield and the target needs to take into account the wave head thickness of the incident wave. The distance between the sidewalls should be greater than the wave head thickness of the incident wave. The recommended spacing is 1.2 to 1.5 times the wave head thickness. Therefore, the spacing between the pressure shield and the pressure hull of the test device is designed by calculating the wave head thickness of the incident wave.

[0055] The generation of underwater shock waves originates from the expansion of detonation products generated instantly by the underwater explosion of explosives. The duration of this process is very short, only in milliseconds. When the shock wave is far away from the explosion source, the propagation speed of the shock wave in the water is approximately attenuated to the speed of sound, so the acoustic method can be used for approximate calculation. In the calculation process of the acoustic method, multiple factors such as the density, compressibility, viscosity of the underwater medium and the energy of the explosive need to be considered to determine the propagation characteristics of the shock wave and the response of the structure. In the coupling process, physical parameters such as the strength and stiffness of the structure also need to be taken into consideration in order to more accurately simulate the response of the structure under the action of the shock wave. The following is the calculation formula for the shock wave pressure P(t):

[0056]

[0057] Where P m represents the peak pressure; θ is the time decay constant;

[0058]

[0059] Where W is the mass of the explosion source; R is the distance between the pressure cover and the center of the explosion source; r is the radius of the explosive package; l and k represent the test coefficients; α and β represent the shock wave pressure and attenuation coefficient.

[0060] Based on the shock propagation law and free boundary shock wave reflection theory, and considering the attenuation effect of the pressure cover on the shock wave, the shock wave transmission distance under one-fold pulse width is adopted, and a safety factor of 1.2 is designed. The shock wave transmission distance of 1.2θ is taken as the distance between the pressure cover and the pressure hull. The shock wave propagation speed in water is 1500m / s. It is calculated that the distance between the pressure cover and the target is d=1500×1.2θ.

[0061] (3) Strength design of the pressure hood based on the lath beam theory

[0062] The two ends of the pressure cover are assumed to be the plate grid between two stiffeners as the research object, the longitudinal plastic deformation damage mechanism of the plate grid is explored, and the plate grid structure under impact load is analyzed using the slat beam model. A simplified mechanical model is established, and the slat beam boundary is a fixed support constraint.

[0063] The upper and lower limits of the precise failure pressure of the clamped rectangular plate are:

[0064]

[0065] p 1 =4M0(1+β 2 ) / B 2

[0066] In the formula, p u is the upper limit of the precise failure pressure; p 1 is the lower limit of the precise breaking pressure; M0 = σH 2 / 4, the ultimate bending moment of the plate frame, σ is the yield stress of the material, H is the thickness of the rectangular plate; B is the length of the rectangular plate; β is the ratio of the width to the length of the rectangular plate; p 1 To precisely break the pressure;

[0067] When β approaches 0, the corresponding static plastic failure behavior is similar to that of a plate with a plastic hinge in the mid-span. The exact failure pressure p 1 :

[0068] p 1 =4M0 / B 2

[0069] Resistance to plastic deformation Q p Defined as the deformation energy E under a certain plastic deformation p and deformation d m Ratio:

[0070]

[0071] Deformation d m When it is less than 5% of the beam span, failure is considered to have occurred.

[0072] Consider a panel rack, where the size of each panel grid is a×b×h (a>b), which corresponds to the 1 / 2 perimeter a of the pressure hood, the distance b between the two ends of the pressure hood, and the thickness h of the pressure hood, such as Figure 5 shown.

[0073] The resistance to plastic deformation calculated by the plastic hinge method is:

[0074]

[0075] Where M p0 =0.25σ sh 2 , is the plastic limit bending moment of the unit width plate, σ s is the ultimate tensile strength of the material, the 1 / 2 circumference a of the pressure hood, the boundary distance b at both ends of the pressure hood, and the thickness h of the pressure hood.

[0076] Based on the above theory and the load size required by the test, the required thickness and material of the pressure cover are calculated.

[0077] The test method of the submarine structure deep-water explosion simulation equivalent test device based on the stress wave principle of the present invention comprises the following steps:

[0078] Step 1: Calculate the material, thickness and size of the pressure cover according to the load size and target size required for the test, and prepare the pressure cover;

[0079] Step 2: Weld the target model and the pressure cover into an integrated structure as a test model, and install lifting lugs on the surface of the test model; the upper lifting lugs can be connected to the crane truck to achieve lifting, entering the water and other operations; the lower lifting lugs can be connected to the counterweight metal block to achieve negative buoyancy in the water for the model to carry out underwater explosion tests;

[0080] Step 3: Arrange the sensors in the target model, then close the hatch and check the water tightness of the test model and the effectiveness of the test cable port;

[0081] Step 4: Inject water from the water injection port of the pressurized cover. When the water fills the interlayer space between the pressurized cover and the target model, stop injecting water. Install a one-way sealing valve on the water injection port to monitor the water filling capacity and pressurization pressure in the pressurized cover in real time. Continue to inject water into the water injection port through the one-way valve to increase the pressure until the pressure gauge on the valve reaches the set pressure; for example, simulate a water depth of 100m, pressurize 1MPa, and so on. The set pressure value P on the pressure gauge is:

[0082]

[0083] Where, P is the set pressure value of the pressure gauge, MPa; H is the depth of the test device, m.

[0084] Step 5: Place the test device into different water depths through the lifting lugs, arrange the explosive source on one side of the test device, detonate, collect data, and test the impact acceleration response, elastic-plastic strain signal, and target shell deflection of the target model; the impact acceleration response and elastic-plastic strain signal are directly output by the data acquisition instrument as complete real domain curves; the deflection deformation is selected in the maximum plastic deformation area, which is the vertical distance from the measuring point 1-7 position to the center of the circle. Figure 6 shown.

[0085] Step 6: Pull the model out of the water, open the hatch, and proceed to the next test.

[0086] Through the deep-water pressurization function of the present invention, simulation effects of 100m, 300m and 450m deep water are achieved, the difficulty of simulating deep-water environment in explosion pool experiments is overcome, and the influence of shock wave reflection waves on test results in previous pressurized tank tests is eliminated. The impact acceleration response, elastic-plastic strain signal, target shell deflection, etc. of the target structure can be tested, and the pressurization cover has no deformation, so the test can be repeated.

[0087] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the above-mentioned implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the present invention. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present invention.

[0088] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A submarine structure deep-water explosion simulation equivalent test device based on stress wave principle, characterized by: Including water pool, explosion source, and test equipment; The test device is arranged inside the water pool, and an explosion source is provided on one side of the test device; the test device includes a pressure cover and a target model; the target model is arranged inside the pressure cover; a water inlet is provided at the top of the pressure cover, and a water outlet is provided at the bottom; the target model includes a pressure shell; the radius of the explosion source, the mass of the explosion source, and the distance between the explosion source and the test device meet the test requirements of the test device after scaling down.

2. The submarine structure deep water explosion simulation equivalent test device based on stress wave principle according to claim 1 is characterized by: The target model is sealed with the front and rear ends of the pressurized cover by a sealing plate, and a test cable port is provided on the sealing plate.

3. The submarine structure deep water explosion simulation equivalent test device based on stress wave principle according to claim 1 is characterized by: The water injection port is equipped with a sealing valve, and a pressure gauge is arranged on the valve.

4. The submarine structure deep water explosion simulation equivalent test device based on stress wave principle according to claim 1 is characterized by: The radius of the explosion source and the size ratio of the target model are both β; the mass ratio of the explosion source is β 3 The explosion source mass W and the distance R between the explosion source and the test device meet the new explosion impact factor C of the target structural characteristics of the test device:

5. The submarine structure deep water explosion simulation equivalent test device based on stress wave principle according to claim 1 is characterized by: The distance d between the target model and the pressure cover is designed according to the distance R between the pressure cover and the explosion source of the test device and the mass W of the explosion source:

6. The submarine structure deep water explosion simulation equivalent test device based on stress wave principle according to claim 1 is characterized by: The distance R between the pressure cover and the explosion source and the explosion source radius r are determined according to the peak pressure P required by the test. m To design, the following relationship is satisfied: Where l and k are test coefficients; α and β are impact pressure attenuation coefficients.

7. The submarine structure deep water explosion simulation equivalent test device based on stress wave principle according to claim 1 is characterized by: The 1 / 2 circumference a of the pressure cover, the distance b between the two ends of the pressure cover, and the thickness h of the pressure cover are determined according to the strength Q of the pressure cover required by the test. p To design, the following relationship is satisfied: In the formula, σ s is the ultimate tensile strength of the material.

8. A test method for the submarine structure deep water explosion simulation equivalent test device based on stress wave principle as claimed in claim 1, characterized in that: The following steps are involved: Step 1: Calculate the material, thickness and size of the pressure cover according to the load size and target size required for the test, and prepare the pressure cover; Step 2: Weld the target model and the pressure cover into an integrated structure as a test model, and install lifting ears on the surface of the test model; Step 3: Arrange sensors in the target model and check the water tightness of the test model and the effectiveness of the test cable port; Step 4: Inject water from the water injection port of the pressurized cover. When the water fills the interlayer space between the pressurized cover and the target model, stop injecting water. Install a one-way sealing valve on the water injection port. Continue to inject water into the water injection port through the one-way valve to increase the pressure until the pressure gauge on the valve reaches the set pressure. Step 5: Place the test device into different water depths through the lifting lugs, arrange the explosion source on one side of the test device, and test the impact acceleration response, elastic-plastic strain signal, and target shell deflection of the target model.

9. The test method of the submarine structure deep water explosion simulation equivalent test device based on stress wave principle according to claim 8 is characterized by: In step 4, the pressure value P is set on the pressure gauge: Where, P is the set pressure value of the pressure gauge, MPa; H is the simulated water depth of the test device, m.

10. The test method of the submarine structure deep water explosion simulation equivalent test device based on stress wave principle according to claim 8 is characterized by: In step 5, the deflection of the target shell is selected in the maximum plastic deformation area, which is the vertical distance of the measuring point position from the center of the circle.

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