A close-in blast loading test device and method

Abstract

This invention relates to a near-field explosion load testing device and method, belonging to the technical field of target plate blast resistance performance. It solves the problem that existing testing systems cannot obtain images of the crushing deformation process of a planar target plate and record the shock wave pressure test signal during near-field planar shock waves. The near-field explosion load testing device of this invention includes an upper cylinder, a target plate mounting base, and a base frame. The target plate mounting base is mounted on the base frame and is used to mount the target plate. The upper cylinder is fixed to the base frame by an upper cylinder support. This near-field explosion load testing device and method can completely and clearly record the crushing and damage process of a target plate after being impacted by a shock wave, obtaining accurate overpressure test signals of the shock wave at different locations on the target plate, providing a data foundation for research on the blast resistance mechanism of target plates such as those with honeycomb structures.

Description

Technical Field

[0001] This invention relates to the field of target plate explosion resistance technology, and in particular to a close-range explosion load testing device and testing method. Background Technology

[0002] In recent years, major national economic projects such as vehicle engineering and aerospace engineering have presented new challenges to the development, design, and application of next-generation lightweight explosion-proof energy-absorbing structures. Honeycomb sandwich structures, with their superior properties such as lightweight and high energy absorption, play a crucial role in resisting blast impacts in special explosion-proof vehicles and equipment. Accurately observing the crushing deformation process of honeycomb structures under the action of blast shock waves to demonstrate the blast-proof performance of the target plate remains a hot topic and a difficult challenge in current research.

[0003] However, in close-range explosive load testing, the formation of plane waves and the recording of the explosion damage process have always been challenging due to issues with explosion flash and detonation products. Currently, in close-range explosive tests conducted by various universities and research institutes, appropriate amounts of explosives are often detonated at a distance to approximate a plane shock wave, which cannot accurately characterize the effect of a plane shock wave. Furthermore, during the explosion, due to the large amount of flash and explosion products generated, high-speed cameras cannot capture and record the crushing and deformation process of the target plate clearly and completely at close range. Due to objective reasons such as errors in the explosive detonation position and the non-horizontal placement of the target plate, it is impossible to accurately test the accurate pressure test signal of the shock wave at different locations on the target plate under the same shock wave. This significantly limits close-range explosive load testing, making it impossible to accurately and clearly record the experimental research process. Summary of the Invention

[0004] In view of the above analysis, the present invention aims to provide a close-range explosive load testing device and testing method to solve the problem that existing test systems cannot obtain close-range planar shock waves, capture images of the crushing deformation process of planar target plates, and record shock wave pressure test signals.

[0005] The objective of this invention is mainly achieved through the following technical solutions:

[0006] A close-range explosive load testing device includes an upper cylinder, a target plate mounting base, and a base frame. The target plate mounting base is mounted on the base frame and is used to mount a target plate. The upper cylinder is fixed to the base frame by an upper cylinder bracket.

[0007] Furthermore, the base frame includes a top plate and a bracket, the bracket being used to support the top plate, and the top plate having multiple threaded holes for connecting the target plate mounting base.

[0008] Furthermore, the target plate mounting base is a square plate, and the target plate mounting base is provided with threaded holes for connecting the base frame and the target plate.

[0009] Furthermore, the target plate, the target plate mounting base, and the top plate of the base frame are connected by long bolts, and the installation height of the target plate mounting base can be adjusted.

[0010] Furthermore, the upper cylinder is a square cylinder, and each of the four sides of the upper cylinder is provided with a first mounting hole for placing a DPR.

[0011] Furthermore, it also includes a target plate replacement plate, which has multiple second mounting holes, the structure of which is the same as that of the first mounting holes.

[0012] Furthermore, it also includes a DPR connector, which can be installed in the first mounting hole and the second mounting hole.

[0013] Furthermore, the target plate is a sandwich structure target plate, which includes an upper panel, a lower panel, and a core plate. The core plate is located between the upper panel and the lower panel, and the core plate is a honeycomb plate.

[0014] A method for testing close-range explosive loads, using the close-range explosive load testing device described in the above technical solution, includes the following steps:

[0015] Step 1: Fix the testing device and install the target plate replacement plate;

[0016] Step 2: Conduct verification experiments;

[0017] Step 3: Replace the target plate with a target plate and conduct the formal test.

[0018] Furthermore, in step 2, a target plate replacement plate is used to conduct a verification test instead of the target plate.

[0019] This invention can achieve at least one of the following beneficial effects:

[0020] (1) The close-range explosion load testing device and testing method of the present invention are based on close-range explosion load testing. It proposes a test method and system for studying the fitting plane shock wave of close-range explosion and testing the deformation of the target plate. It can completely and clearly record the crushing and damage process of the target plate after being impacted by the shock wave, and obtain the accurate overpressure test signal of the shock wave at different positions of the target plate, providing a data basis for studying the explosion resistance mechanism of target plates such as honeycomb structures.

[0021] (2) The close-range explosive load testing device and testing method of the present invention realize the conversion of a spherical shock wave from a free explosion in the air at close range within a proportional distance range into a planar shock wave.

[0022] (3) The testing device of the present invention can effectively block the explosion products and flames, and help the high-speed camera to capture the crushing and deformation process of the flat target plate clearly and at close range.

[0023] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0024] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0025] Figure 1 This is a schematic diagram of the structure of the close-range explosive load testing device according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the target plate structure according to an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the base frame structure according to an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the target plate replacement plate in an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the structure of the DPR connector according to an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram showing the positions of five points taken on the target plate according to an embodiment of the present invention;

[0031] Figure 7 For simulation experiments Figure 6 Time-pressure curves at five points on the target plate;

[0032] Figure 8 This is a pressure cloud map at a location where 20g of explosive is used in a simulation test and the distance between the explosive and the target plate is 40cm.

[0033] Figure 9 This is a schematic diagram of the normal oblique reflection of a shock wave on a rigid wall.

[0034] Figure 10 A schematic diagram of the different reflection zones of a shock wave;

[0035] Figure 11 This is a schematic diagram of the wall reflection process of a shock wave.

[0036] Figure label:

[0037] 1-Upper cylinder, 2-Target plate, 21-Upper panel, 22-Core plate, 23-Angle plate, 24-Lower panel, 3-Upper cylinder bracket, 4-Target plate mounting base, 5-Base frame. Detailed Implementation

[0038] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0039] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the term "connected" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0040] Throughout the text, the terms “top,” “bottom,” “above,” “below,” and “on top” refer to the relative positions of components of the device, such as the relative positions of the top and bottom substrates within the device. It is understood that the device is multifunctional and independent of its spatial orientation.

[0041] Example 1

[0042] One embodiment of the present invention, such as Figures 1 to 5 As shown, a close-range explosive load testing device is disclosed, including an upper cylinder 1, a target plate mounting base 4, and a base frame 5. The base frame 5 provides support for the close-range explosive load testing device of this embodiment. The target plate mounting base 4 is mounted on the base frame 5 and is used to mount the target plate 2. The upper cylinder 1 is fixed on the base frame 5 by an upper cylinder bracket 3.

[0043] Specifically, the base frame 5 includes a top plate and a support bracket. The support bracket supports the top plate, and the top plate has multiple threaded holes for connecting the target plate mounting base 4. In this embodiment, to prevent the base frame 5 from being displaced due to impact during the test, the support bracket is fixedly connected to the ground.

[0044] Furthermore, the target plate mounting base 4 is a square plate, and the target plate mounting base 4 is provided with threaded holes for connecting the base frame 5 and the target plate 2.

[0045] Furthermore, the target plate 2, the target plate mounting base 4, and the top plate of the base frame 5 are connected by long bolts. In this embodiment, the installation height of the target plate mounting base 4 can be adjusted by adjusting the position of the nut or by installing a shim between the target plate mounting base 4 and the top plate, thereby adjusting the installation height of the target plate 2.

[0046] In this embodiment, the upper cylinder 1 is a square cylinder, and each of the four side plates of the upper cylinder 1 is provided with a first mounting hole for placing a DPR (Digital Pressure Recorder). In this embodiment, each side of the upper cylinder 1 is provided with two first mounting holes.

[0047] Furthermore, this embodiment also includes a target plate replacement plate. During the verification test, the target plate replacement plate is installed in the position of the target plate 2, replacing the target plate 2. The target plate replacement plate can test whether the shock wave generated by the explosion is a planar shock wave, estimate the peak range and positive pressure time of the shock wave, and compare empirical formula data and simulation data to reduce the loss of explosives, target plate 2 and time in the simulation test.

[0048] In this embodiment, as Figure 4 As shown, the target replacement plate has multiple second mounting holes, the structure of which is the same as that of the first mounting holes. The second mounting holes penetrate the target replacement plate and are used to place the DPR (Displacement Receptor).

[0049] Figure 5 The DPR connector is shown. The DPR connector can be installed in the mounting holes of the side plate of the upper cylinder 1 and the target plate replacement plate. The size of the DPR connector matches the size of the first mounting hole and the second mounting hole. The size of the DPR can completely fill the first mounting hole and the second mounting hole. On the one hand, it can securely install the DPR, and on the other hand, it can prevent the shock wave pressure test signal from changing due to air passage in the first mounting hole or the second mounting hole.

[0050] Furthermore, the DPR connector has an axial through hole for fixing the DPR pressure sensor, and the signal wire of the pressure sensor is led out through the through hole and connected to the signal receiver.

[0051] Example 2

[0052] One embodiment of the present invention discloses a close-range explosive load testing device, suitable for a proportional distance r ≥ 0.9 m / kg. 1 / 3 Furthermore, the distance between the explosive and the target plate 2 is between 20cm and 50cm. Here, the proportional distance r is the length of the explosive from the test location divided by the cube root of the explosive charge. The proportional distance is used to represent the power of the shock wave during the explosion; the smaller the power, the larger the proportional distance.

[0053] In this embodiment, the upper cylinder 1 is a square cylinder with a height of 50cm and an inner diameter of 150mm*150mm. The side plate of the upper cylinder 1 has a total of 8 first mounting holes for placing the DPR (Digital Removal Tool). Each first mounting hole consists of a first through hole with a diameter of 25mm and a second through hole with a diameter of 20mm, and the first and second through holes are coaxial. The first through hole is 5mm deep, and the second through hole is 25mm deep. The first through hole is located close to the inner surface of the upper cylinder 1.

[0054] The length and width of the target plate mounting base 4 are 250mm and 250mm respectively.

[0055] The target plate 2 is a sandwich structure target plate, comprising an upper panel 21, a lower panel 24, and a core plate 22. Both the upper panel 21 and the lower panel 24 are made of Q345 steel plate. The upper panel 21 has a length * width of 150mm * 150mm, and the lower panel has a length * width of 250mm * 250mm. The core plate 22 is located between the upper panel 21 and the lower panel 24. The core plate 22 is a honeycomb panel.

[0056] Furthermore, the target plate 2 in this embodiment is also provided with corner plates 23. The corner plates 23 are angle steels and are installed on the lower panel 24, with the four corner plates 23 located at the four corners of the core plate 22 respectively. The corner plates 23 do not directly contact the core plate 22 and are used to prevent the core plate 22 from laterally sliding during the crushing deformation process.

[0057] The target replacement plate has a length and width of 250mm x 250mm. It has multiple second mounting holes, each consisting of a 25mm diameter third through hole and a 20mm diameter fourth through hole, which are coaxial. The third through hole is 5mm deep, and the fourth through hole is 25mm deep. The third through hole is located near the upper surface of the target replacement plate.

[0058] Example 3

[0059] One embodiment of the present invention discloses a method for testing close-range explosive loads using the close-range explosive load testing device of Embodiment 1.

[0060] In this embodiment, to verify the effectiveness of the close-range explosive load testing device, simulation was first performed using ANSYS / DYNA simulation software.

[0061] During the simulation, five locations were selected on the surface of target plate 2, such as... Figure 6 As shown, five points are distributed along the diagonal of the target plate 2 and extend from one corner of the target plate 2 to the center of the target plate 2, thereby fully simulating the surface position of the target plate 2.

[0062] In this embodiment, six scenarios were simulated: 20g of explosive at a distance of 30cm, 40cm, and 49cm; 30g of explosive at a distance of 30cm, 40cm, and 49cm; and 30g of explosive at a distance of 49cm. The time-pressure curves for five locations on the target plate 2 surface under these six scenarios were obtained, as shown below. Figure 7 (a)- Figure 7 As shown in (f). By Figure 7 (a)- Figure 7 (f) It can be seen that within the applicable range of this embodiment (proportional distance r ≥ 0.9 m / kg) 1 / 3 In each case, the time-pressure curves at the five positions of the target plate basically overlap, proving that the pressure at different positions of the target plate 2 is basically the same. In other words, the pressure at different positions of the shock wave is basically the same, and the shock wave is a planar shock wave.

[0063] Figure 8 (a)- Figure 8 (i) The pressure cloud diagrams of target plate 2 at 0 μs, 80 μs, 160 μs, 200 μs, 250 μs, 300 μs, 450 μs, 550 μs and 600 μs are shown respectively when 20 g of explosive is 40 cm away from the target plate. Figure 8 (a)- Figure 8 (i) It can be seen that at each time point, the cloud map of the target plate 2 plane position at the same time point is the same color, that is, the pressure at each position on the surface of the target plate 2 is the same, indicating that the shock wave is a plane shock wave, which further proves the effectiveness of the close-range explosive load testing device of the present invention.

[0064] The close-range explosive load testing method in this embodiment specifically includes the following steps:

[0065] Step 1: Fix the test setup and install the target plate replacement plate:

[0066] Before the test, first fix each part of the test device and install the target plate replacement plate at the position of target plate 2. Then, place a high-speed camera at a certain distance from the test device (e.g., 2m) at the same height as target plate 2. Then, place DPR in the first mounting hole and the second mounting hole, test the pressure signal of the pressure sensor of DPR, and establish a close-range explosive load test system.

[0067] Step 2: Conduct verification experiments:

[0068] Based on the required proportional distance for the experiment, calculate the appropriate explosive charge and the distance between the explosive and the target plate replacement plate. Use the same explosive charge as in the formal experiment to verify the consistency of the waveform pressure test signals for each DPR (Displacement Point). If the waveform pressure test signals at different positions on the target plate replacement plate are verified to be essentially consistent, meaning the shock waves at different positions on the target plate 2 surface are the same, then a planar shock wave is formed. If they are inconsistent, it indicates that the proportional distance exceeds the applicable range of the testing device, requiring a reduction in the explosive charge or a change in the explosive's position.

[0069] In this embodiment, since the target plate 2 is expensive, in order to avoid wasting the target plate 2, the target plate is first used to replace the plate for verification test to verify the consistency between the test and the simulation. At the same time, the robustness of the test device is verified.

[0070] Step 3: Replace the target plate with a replacement target plate and conduct the formal test:

[0071] During the formal test, the target plate was first removed and replaced with a target plate 2. Then, the explosive of a specified amount was fixed at a specified height on the center line inside the upper cylinder 1 by a suspension line. Subsequently, the explosive was detonated by a detonator. The explosive underwent a free-field spherical explosion in the upper cylinder 1. The shock wave was then reflected multiple times through the square inner wall of the upper cylinder 1. When it reached the target plate 2, the shock wave was reflected and superimposed multiple times, approximating a planar shock wave. The DPR installed in the side plate of the upper cylinder 1 recorded and stored the planar shock wave pressure test signal. A high-speed camera captured and recorded the complete and clear process of damage and deformation of the target plate 2.

[0072] In the experiment, when a spherical or near-spherical TNT charge explodes in the air, at any comparative distance from the explosion center... Peak overpressure ΔP at the location m It can be calculated using Backer's formula:

[0073]

[0074] Wherein, ΔP m Peak overpressure (MPa); For proportional distance, R is the distance to the explosion center (m); M is the weight of the explosive (kg).

[0075] When the shock wave forms an angle with the rigid surface Upon incident, the shock wave undergoes oblique reflection. There are two types of oblique reflection of the shock wave: one is normal oblique reflection (such as...) Figure 9 As shown in the image, one type is irregular oblique reflection, also known as Mach reflection. The type of reflection is related to the incident angle of the shock wave. When the incident angle is small, regular oblique reflection occurs; when the incident angle exceeds a certain critical value... When the critical angle for Mach reflection is reached, Mach reflection occurs. As the incident wave pressure increases, It continuously decreases and tends to a limit value of 40° (e.g., Figure 10 As shown). After the shock wave is continuously reflected and superimposed on the rigid inner wall of the upper cylinder 1, when it reaches the target plate 2, the shock wave interface approximately reaches the plane wave interface (as shown). Figure 11 (As shown).

[0076] In summary, the close-range explosive load testing device and method provided by this embodiment of the invention realizes the conversion of a spherical shock wave from a free-exploding spherical shock wave in the air at close range within a proportional distance range into a planar shock wave. The testing device of this embodiment can effectively shield the explosion products and flash, helping the high-speed camera to completely and clearly capture the crushing and deformation process of the planar target plate at close range. Using the testing device of this embodiment, the damaged target plate and the shock wave pressure test signals at different positions of the target plate under the same shock wave can be accurately obtained, ensuring the synchronization of the test data and the video of the target plate deformation process, and preventing errors caused by different tests.

[0077] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A close-range explosive load testing device, characterized in that, It includes an upper cylinder (1), a target plate mounting base (4), and a base frame (5). The target plate mounting base (4) is mounted on the base frame (5) and is used to mount the target plate (2). The upper cylinder (1) is fixed to the base frame (5) by an upper cylinder bracket (3). The upper cylinder (1) is a square cylinder, and the four sides of the upper cylinder (1) are respectively provided with first mounting holes for placing DPR. The target plate (2) is a sandwich structure target plate. The target plate (2) includes an upper panel (21), a lower panel (24) and a core plate (22). The core plate (22) is located between the upper panel (21) and the lower panel (24). The core plate (22) is a honeycomb plate. It also includes a target plate replacement plate, which is provided with a plurality of second mounting holes, the structure of which is the same as that of the first mounting holes; After the shock wave is continuously reflected and superimposed by the rigid inner wall of the upper cylinder (1), when it reaches the position of the target plate (2), the shock wave interface approximately reaches the plane wave interface, realizing the transformation of the spherical shock wave that explodes freely in the air at close range within a proportional distance range into a plane shock wave.

2. The close-range explosive load testing device according to claim 1, characterized in that, The base frame (5) includes a top plate and a bracket. The bracket is used to support the top plate. The top plate is provided with multiple threaded holes for connecting the target plate mounting base (4).

3. The close-range explosive load testing device according to claim 2, characterized in that, The target plate mounting base (4) is a square plate, and the target plate mounting base (4) is provided with threaded holes for connecting the base frame (5) and the target plate (2).

4. The close-range explosive load testing device according to claim 3, characterized in that, The top plates of the target plate (2), the target plate mounting base (4), and the base frame (5) are connected by long bolts, and the installation height of the target plate mounting base (4) can be adjusted.

5. The close-range explosive load testing device according to claim 4, characterized in that, It also includes a DPR connector, which can be installed in the first mounting hole and the second mounting hole.

6. A method for testing close-range explosive loads, using the close-range explosive load testing apparatus according to any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Fix the testing device and install the target plate replacement plate; Step 2: Conduct verification experiments: Based on the required proportional distance for the experiment, calculate the appropriate amount of explosive and the distance between the explosive and the target plate replacement plate; use the same amount of explosive as in the formal experiment to verify whether the waveform pressure test signals of each DPR are consistent; if the waveform pressure test signals at different positions of the target plate replacement plate are consistent, then a planar shock wave is formed; if they are inconsistent, then the amount of explosive needs to be reduced or the position of the explosive needs to be moved. Step 3: Replace the target plate (2) with the target plate replacement plate and conduct the formal test: During the formal test, the target plate replacement plate was first removed and the target plate (2) was installed. Then, the explosive of a specified amount was fixed at a specified height on the center line inside the upper cylinder (1) by a suspension line. Subsequently, the explosive was detonated by a detonator. The explosive underwent a free-field spherical explosion in the upper cylinder (1). The shock wave was reflected multiple times through the square inner wall of the upper cylinder (1). When it reached the target plate (2), the shock wave was reflected and superimposed multiple times, and it became approximately a planar shock wave. The DPR installed in the side plate of the upper cylinder (1) recorded and stored the planar shock wave pressure test signal. The high-speed camera captured and recorded the complete and clear process of the damage and deformation of the target plate (2).

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