Amplification Test Apparatus and Method for Nonlinear Response of Charge Structure under Multi-Pulse Loading

Abstract

This invention discloses a multi-pulse loading nonlinear response amplification test device and method for explosive structures, relating to the field of structural and material response simulation technology under impact loads. It includes a loading section and a structural response section. The loading section includes a projectile A, which has a large-diameter end and a small-diameter end. A projectile B is disposed outside the small-diameter end of projectile A, and a projectile C is disposed outside projectile B. An adjusting ring B is disposed at the end of projectile B near the large-diameter end of projectile A, and an adjusting ring C is disposed at the end of projectile C near the large-diameter end of projectile A. The masses of projectiles A, B, and C are equal. The structural response section includes a limiting block and a mass block, with a force transmission rod disposed between the limiting block and the mass block. The mass block has a loading through-hole and a mounting hole for the force transmission rod. This test device can achieve loading pulses of no less than 3 times, explosive pressure on the order of hundreds of MPa, and pressure amplitude amplification of approximately 1.9 times, with a short test cycle and low cost.

Description

Technical Field

[0001] This invention relates to the field of response simulation technology for structures and materials under impact loads, and specifically to a test apparatus and method for amplifying the nonlinear response of a charge structure under multi-pulse loading. Background Technology

[0002] During penetration of a multi-layered target, the projectile is subjected to repeated impact loads, and the internal explosive charge experiences repeatedly propagating compressive and tensile stresses, which may lead to damage and fracture of the explosive charge. Especially when the external load couples with the structural response of the explosive charge, amplifying the nonlinear response can occur, potentially causing a significant localized temperature rise in the explosive charge, leading to ignition. In multi-layered target penetration tests, the projectile is in flight, and apart from accelerometers and high-speed photography, it is difficult to apply other measurement and diagnostic methods, making it impossible to directly obtain the response process of the internal explosive charge. Therefore, in recent years, some researchers have focused on developing experimental techniques for repeated impact loading to simulate the response process of the explosive charge within the projectile during penetration of a multi-layered target.

[0003] Currently, relatively mature impact loading experimental techniques, such as Hopkinson bar technology, light air gun technology, falling hammer impact test technology, artillery technology, and electric gun technology, are all single-load techniques used to study the response process of structures or materials under a single pulse. They cannot achieve multi-pulse loading on the tested structure or material.

[0004] In recent years, several multi-pulse loading test devices have been developed. For example, the invention patent "Impact Test Device" (application number: 201410041002.2) by Shi Gengchen et al. utilizes gravitational potential energy to accelerate multiple impact hammers to achieve multi-pulse loading; the invention patent "A Multi-Parameter Multiple Impact Loading Test Device" (application number: 201821745932.9) by Nie Shaoyun et al. simulates multi-layer target impact on projectiles to achieve multi-pulse loading; and the invention patent application "A Multiple Impact Loading Test Device and Method" (application number: 201910506011.X) by Li Hongbin et al. uses electromagnetic drive to drive multiple projectiles to achieve multi-pulse loading. However, the load patterns obtained by these test devices are not easily controlled, and the amplification of structural nonlinear response cannot be achieved.

[0005] Therefore, current loading test methods or test devices cannot achieve multi-pulse loading on the tested structure or material, the test results are inaccurate, and the nonlinear response of the structure cannot be amplified, which has significant limitations. Summary of the Invention

[0006] The technical problem to be solved by the present invention is that the current pulse loading test methods or devices cannot achieve multi-pulse loading on the tested structure or material, the test results are inaccurate, the structural nonlinear response cannot be amplified, and there are significant limitations. The purpose is to provide a test device and method for amplifying the nonlinear response of a charge structure under multi-pulse loading, which solves the problems of the current pulse loading test methods or devices being unable to achieve multi-pulse loading on the tested structure or material, inaccurate test results, unable to amplify the structural nonlinear response, and having significant limitations.

[0007] This invention is achieved through the following technical solution:

[0008] On one hand, this application provides a multi-pulse loading nonlinear response amplification test device for a charge structure, including a loading part and a structural response part. The loading part includes a bullet A, which has a large diameter end and a small diameter end. A bullet B is disposed outside the small diameter end of the bullet A, and a bullet C is disposed outside the bullet B. An adjustment ring B is disposed at the end of the bullet B near the large diameter end of the bullet A, and an adjustment ring C is disposed at the end of the bullet C near the large diameter end of the bullet A.

[0009] Bullets A, B, and C have equal mass.

[0010] The structural response section includes a limiting block and a mass block, with a force transmission rod disposed between the limiting block and the mass block; the mass block is provided with a loading through hole and a mounting hole for the force transmission rod.

[0011] Among them, bullets A, B, and C are made of 30CrMnSi or other higher strength steel. According to the test impact speed, the minimum yield strength of bullets A, B, and C without plastic deformation can be pre-calculated and analyzed using the finite element numerical simulation method to ensure that the selected materials do not cause plastic deformation in the test of bullets A, B, and C.

[0012] The diameter of bullet A at its smaller diameter end is smaller than the inner diameter of bullet B, and the outer diameter of bullet B is smaller than the inner diameter of bullet C. Adjusting rings B and C have variable heights. Bullet B has the same inner and outer diameter as adjusting ring B, and the two are connected in series and fitted into bullet A, making close contact with the larger diameter end of bullet A. Bullet C has the same inner and outer diameter as adjusting ring C, and the two are connected in series and fitted into bullet A, making close contact with the larger diameter end of bullet A.

[0013] The force transmission rod is made of 30CrMnSi or other higher strength steel. The cross-section of the force transmission rod is convex, integrally formed from a smaller diameter cylindrical end and bottom. The limiting block is rectangular in shape, segmented into stepped, hollow sections that form the loading through-hole and the mounting holes for the force transmission rod.

[0014] The test device can achieve the effect of loading pulses of no less than 3 times, charging pressure on the order of hundreds of megapascals, and pressure amplitude amplification of about 1.9 times. It has initially realized the simulation of the charging response characteristics during the penetration process, and the test cycle is short and the cost is low.

[0015] Furthermore, the diameter of the loading through hole is smaller than the diameter of the mounting hole, and a limiting protrusion is provided at the end of the force transmission rod mounted on the mass block, the outer diameter of the limiting protrusion being larger than the outer diameter of the loading through hole.

[0016] Furthermore, a washer ring is provided on the force transmission rod located within the mounting hole.

[0017] The height of the washer is less than the depth of the mounting hole.

[0018] Furthermore, the washer ring is made of a material with a low coefficient of friction.

[0019] Furthermore, the material used to prepare the gasket ring includes polytetrafluoroethylene.

[0020] Furthermore, the force transmission rod is connected to the mass block via a detachable connection assembly.

[0021] Furthermore, the detachable connection assembly includes a base plate mounted on the mass block by screws, an outer cone cylinder mounted on the base plate by screws, and an inner cone cylinder embedded within the outer cone cylinder.

[0022] The mass block is rectangular in shape, with the sample installed inside the inner cone. The outer cone secures the inner cone and is mounted on a base plate with screws. The base plate is then mounted on the mass block with screws. All components are coaxial. The inner cone is a 180° cone that is embedded in the outer cone for easy disassembly and recovery after testing.

[0023] Furthermore, the mass block is provided with a limiting groove, and the base plate is provided with an installation block installed in the limiting groove.

[0024] By setting a limiting groove on the mass block, the mounting block of the base plate is embedded into the limiting groove and then locked with screws, making installation more convenient and improving the fixing effect of the base plate.

[0025] Furthermore, a sample placement platform is provided on the base plate.

[0026] The sample placement platform is coaxial with the force transmission rod.

[0027] On the other hand, a test method for an amplification test device for the nonlinear response of a charge structure under multi-pulse loading includes the following operations:

[0028] Obtain the axial natural frequency of the structural response part: Establish the finite element model of the device, apply periodic loads of different frequencies to the load-bearing end face of the force transmission rod, analyze the maximum magnification of the sample under different frequency conditions, obtain the frequency-amplitude curve, and thus obtain the axial natural frequency of the structural response part.

[0029] Adjusting the frequency of the loading load: The frequency of the loading load is determined by the impact velocity and length of bullets A, B, and C, as well as the axial distance between them. The frequency of the loading load is obtained by processing the loading load using the Fourier transform method. The axial distance is adjusted by changing the height of the adjusting rings B and C. The frequency of the loading load can be freely adjusted according to the requirements.

[0030] During the test, the loading part was placed inside the gun barrel. High-pressure gas was released to drive the loading part to move at high speed and enter the loading through hole of the limiting block. Bullets A, B and C then struck the end surface of the force transmission rod installed at one end of the limiting block in sequence.

[0031] A thin-film pressure gauge for testing the sample is placed between the base plate and the sample.

[0032] An accelerometer is installed in the middle of the force transmission rod to measure overload information.

[0033] The velocities of bullets A, B, and C were determined using an optical measurement system.

[0034] The test method of this test device can achieve three consecutive impact loadings with amplitudes up to the hundreds of megapascals and pulse widths down to the sub-millisecond level. The overall structure is stable, reusable, and has good test repeatability. On the one hand, it provides a test method for studying the unexpected ignition of the charge during actual penetration. On the other hand, it is expected to be developed into a standard test method for simulating the safety of the charge under multi-pulse loading of penetration, and applied to the safety identification and assessment of the charge of penetration weapons.

[0035] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0036] (1) The test device can achieve the effect of loading pulses of no less than 3 times, charging pressure on the order of hundreds of MPa, and pressure amplitude amplification of about 1.9 times. It has initially realized the simulation of the charging response characteristics of the penetration process, and the test cycle is short and the cost is low.

[0037] (2) The test method of this test device can achieve three consecutive impact loadings with an amplitude of up to hundreds of megapascals and a pulse width of up to the sub-millisecond level. The overall structure is stable, reusable, and has good test repeatability. On the one hand, it provides a test method for studying the unexpected ignition of the charge during actual penetration. On the other hand, it is expected to be developed into a standard test method for simulating the safety of the charge under multi-pulse loading of penetration, and applied to the safety identification and assessment of the charge of penetration weapons. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0039] Figure 1 This is a perspective view of a nonlinear response amplification test device for a multi-pulse loading structure according to the present invention;

[0040] Figure 2 This is a cross-sectional view of a nonlinear response amplification test device for a charge structure under multi-pulse loading according to the present invention;

[0041] Figure 3 This is a cross-sectional view of the structural response portion in this invention;

[0042] Figure 4 for Figure 2 Enlarged view of A in the middle;

[0043] Figure 5 This is a schematic diagram of the sample placement section in this invention;

[0044] Figure 6 This is a graph showing the pressure on the bottom surface of the sample under test as a function of time in Example 1 of the present invention, where the horizontal axis represents time in ms and the vertical axis represents pressure in MPa.

[0045] Figure 7 This is a graph showing the pressure on the bottom surface of the sample under test as a function of time in Example 2 of the present invention, where the horizontal axis represents time in ms and the vertical axis represents pressure in MPa.

[0046] Figure 8 This is a graph showing the pressure on the bottom surface of the sample under test as a function of time in Example 3 of the present invention, where the horizontal axis represents time in ms and the vertical axis represents pressure in MPa.

[0047] Figure 9 This is a graph showing the pressure change over time on the bottom surface of the sample under test in Example 4 of the present invention, where the horizontal axis represents time in ms and the vertical axis represents pressure in MPa.

[0048] The attached diagram shows the markings and corresponding component names:

[0049] 01-Loading section, 02-Limiting block, 03-Force transmission rod, 04-Outer cone, 05-Base plate, 06-Mass block, 07-Loading through hole, 08-Washer ring, 09-Mounting hole, 10-Sample, 11-Adjusting ring B, 12-Adjusting ring C, 13-Bullet A, 14-Bullet B, 15-Bullet C, 16-Inner cone, 17-Mounting block, 18-Placement platform. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0051] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0052] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0053] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, a joint, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0054] Example 1

[0055] like Figures 1 to 6 As shown, this embodiment provides a multi-pulse loading-based nonlinear response amplification test device for a propellant structure, including a loading section 01 and a structural response section. The loading section 01 includes a bullet A13, which has a large-diameter end and a small-diameter end. A bullet B14 is disposed outside the small-diameter end of bullet A13, and a bullet C15 is disposed outside the bullet B14. An adjustment ring B11 is disposed at the end of bullet B14 near the large-diameter end of bullet A13, and an adjustment ring C12 is disposed at the end of bullet C15 near the large-diameter end of bullet A13.

[0056] Bullets A13, B14, and C15 have the same mass; the force transmission rod 03, bullets A13, B14, and C15 are made of 30CrMnSi material.

[0057] The structural response section includes a limiting block 02 and a mass block 06, with a force transmission rod 03 provided between the limiting block 02 and the mass block 06; the mass block 06 is provided with a loading through hole 07 and a mounting hole 09 for the force transmission rod 03.

[0058] The diameter of the loading through hole 07 is smaller than the diameter of the mounting hole 09. A limiting protrusion is provided at the end of the force transmission rod 03 mounted on the mass block 06. The outer diameter of the limiting protrusion is larger than the outer diameter of the loading through hole 07.

[0059] Specifically, a washer 08 is provided on the force transmission rod 03 located inside the mounting hole 09. The height of the washer 08 is less than the depth of the mounting hole 09.

[0060] Specifically, the materials used to prepare gasket 08 include polytetrafluoroethylene.

[0061] Specifically, the force transmission rod 03 is connected to the mass block 06 via a detachable connection assembly. The detachable connection assembly includes a base plate 05 mounted on the mass block 06 by screws, an outer cone 04 mounted on the base plate 05 by screws, and an inner cone 16 embedded inside the outer cone 04.

[0062] The mass block 06 is rectangular in shape. The sample 10 is installed inside the inner cone 16. The outer cone 04 fastens the inner cone 16 and is mounted on the base plate 05 with screws. The base plate 05 is mounted on the mass block 06 with screws. All components are coaxial. The inner cone 16 is a 180° cone that is embedded in the outer cone 04, facilitating disassembly and recycling after the test.

[0063] Specifically, a limiting groove is provided on the mass block 06, and an installation block 17 is installed in the limiting groove on the base plate 05.

[0064] By setting a limiting groove on the mass block 06, the mounting block 17 of the base plate 05 is embedded into the limiting groove and then locked with screws, making installation more convenient and improving the fixing effect of the base plate 05.

[0065] Specifically, a sample 10 placement platform 18 is provided on the base plate 05. The sample 10 placement platform 18 is coaxial with the force transmission rod 03.

[0066] The test device can achieve the effect of loading pulses of no less than 3 times, charging pressure on the order of hundreds of megapascals, and pressure amplitude amplification of about 1.9 times. It has initially realized the simulation of the charging response characteristics during the penetration process, and the test cycle is short and the cost is low.

[0067] Example 2

[0068] like Figures 1 to 5 As shown, this embodiment provides a test method for a nonlinear response amplification test device for a propellant structure under multi-pulse loading. In this embodiment, there are three bullets, including bullet A13, bullet B14 and bullet C15. All bullets are made of steel and have a mass of 0.38 kg. The three bullets are coaxial. The height difference between bullets A13 and B14 is 18 mm and 20 mm respectively.

[0069] The force transmission rod 03 is made of steel, with a diameter of 60mm and a thickness of 40mm for the end disc, and a rod diameter of 20mm. The sample to be tested 10 is made of polytetrafluoroethylene, with a diameter of 20mm and a height of 20mm.

[0070] The specific experimental procedure is as follows:

[0071] First, the axial natural frequency of the structural response part is obtained: a finite element model of the device is established, and periodic loads of different frequencies are applied to the loaded end face of the force transmission rod 03. The maximum magnification of sample 10 under different frequency conditions is analyzed, and the first-order axial natural frequency of the structural response part is found to be approximately 910Hz.

[0072] Secondly, the frequency of the loading load is adjusted: the frequency of the loading load is determined by the impact velocity and length of bullets A13, B14 and C15, as well as the axial distance between them. The frequency of the loading load is obtained by processing the loading load using the Fourier transform method. The axial distance is adjusted by changing the height of the adjusting rings B11 and C12. The frequency of the loading load can be freely adjusted according to the requirements.

[0073] Finally, the high-pressure gas chamber valve is opened, and the high-pressure gas drives bullets A13, B14 and C15 to gradually accelerate and strike the force transmission rod 03 in sequence. The force is transmitted to the sample 10 to be tested, and the pressure sensor collects the pressure signal on the bottom surface of the sample 10. After the bullets are impacted, they bounce back in sequence, and the pressure signal decays to 0, and the test ends.

[0074] like Figure 6 As shown, the specific experimental results of this embodiment are as follows:

[0075] The three bullets impacted at a velocity of 21.1 m / s, with a loading frequency of approximately 1110 Hz, which is 22% higher than the structure's natural frequency. Figure 6The pressure variation curve of the bottom surface of the sample 10 as a function of time is shown. The horizontal axis represents time in milliseconds (ms), and the vertical axis represents pressure in MPa (MPa). Three pressure pulses are observed: the first peak pressure is approximately 303 MPa with a pulse width of approximately 0.6 ms; the second peak pressure is approximately 339 MPa with a pulse width of approximately 0.9 ms; and the third peak pressure is approximately 210 MPa with a pulse width of approximately 0.6 ms. The pressure peaks show an initial increase followed by a decrease. This indicates that when the loading frequency deviates significantly from the natural frequency of the structural response, the response is not amplified.

[0076] Example 3

[0077] like Figures 1 to 5 As shown, this embodiment provides a test method for a nonlinear response amplification test device for a propellant structure under multi-pulse loading. In this embodiment, there are three bullets, including bullet A13, bullet B14 and bullet C15. All bullets are made of steel and have a mass of 0.38 kg. The three bullets are coaxial. The height difference between bullets A13 and B14 is 17 mm and 19 mm respectively.

[0078] The force transmission rod 03 is made of steel, with a diameter of 60mm and a thickness of 40mm for the end disc, and a rod diameter of 20mm. The sample to be tested 10 is made of polytetrafluoroethylene, with a diameter of 20mm and a height of 20mm.

[0079] The specific experimental procedure is as follows:

[0080] First, the axial natural frequency of the structural response part is obtained: a finite element model of the device is established, and periodic loads of different frequencies are applied to the loaded end face of the force transmission rod 03. The maximum magnification of sample 10 under different frequency conditions is analyzed, and the first-order axial natural frequency of the structural response part is found to be approximately 910Hz.

[0081] Secondly, the frequency of the loading load is adjusted: the frequency of the loading load is determined by the impact velocity and length of bullets A13, B14 and C15, as well as the axial distance between them. The frequency of the loading load is obtained by processing the loading load using the Fourier transform method. The axial distance is adjusted by changing the height of the adjusting rings B11 and C12. The frequency of the loading load can be freely adjusted according to the requirements.

[0082] Finally, the high-pressure gas chamber valve is opened, and the high-pressure gas drives bullets A13, B14 and C15 to gradually accelerate and strike the force transmission rod 03 in sequence. The force is transmitted to the sample 10 to be tested, and the pressure sensor collects the pressure signal on the bottom surface of the sample 10. After the bullets are impacted, they bounce back in sequence, and the pressure signal decays to 0, and the test ends.

[0083] like Figure 7 As shown, the specific experimental results of this embodiment are as follows:

[0084] The three bullets impacted at a velocity of 21.1 m / s, with a loading frequency of approximately 1170 Hz, which is about 29% higher than the structure's natural frequency. Figure 7 The curve showing the pressure change over time on the bottom surface of sample 10 is presented. The horizontal axis represents time (ms), and the vertical axis represents pressure (MPa). The curve shows three pressure pulses; the first pressure pulse has a peak value of 308 MPa and a pulse width of approximately 0.6 ms. Figure 6 The results for NO.0511-1 are consistent, but the latter two pressure curves are significantly different. The peak value of the second pressure pulse drops to approximately 179 MPa with a pulse width of approximately 0.6 ms, while the peak value of the third pressure pulse is approximately 233 MPa with a pulse width of approximately 0.6 ms. This indicates that the change in the loading frequency affects the pressure response history, leading to... Figure 6 The results differed.

[0085] Example 4

[0086] like Figures 1 to 5 As shown, this embodiment provides a test method for a nonlinear response amplification test device for a propellant structure under multi-pulse loading. In this embodiment, there are three bullets, including bullet A13, bullet B14 and bullet C15. All bullets are made of steel and have a mass of 0.38 kg. The three bullets are coaxial. The height difference between bullets A13 and B14 is 18 mm and 20 mm respectively.

[0087] The force transmission rod 03 is made of steel, with a diameter of 60mm and a thickness of 40mm for the end disc, and a rod diameter of 20mm. The sample to be tested 10 is made of polytetrafluoroethylene, with a diameter of 20mm and a height of 20mm.

[0088] The specific experimental procedure is as follows:

[0089] First, the axial natural frequency of the structural response part is obtained: a finite element model of the device is established, and periodic loads of different frequencies are applied to the loaded end face of the force transmission rod 03. The maximum magnification of sample 10 under different frequency conditions is analyzed, and the first-order axial natural frequency of the structural response part is found to be approximately 910Hz.

[0090] Secondly, the frequency of the loading load is adjusted: the frequency of the loading load is determined by the impact velocity and length of bullets A13, B14 and C15, as well as the axial distance between them. The frequency of the loading load is obtained by processing the loading load using the Fourier transform method. The axial distance is adjusted by changing the height of the adjusting rings B11 and C12. The frequency of the loading load can be freely adjusted according to the requirements.

[0091] Finally, the high-pressure gas chamber valve is opened, and the high-pressure gas drives bullets A13, B14 and C15 to gradually accelerate and strike the force transmission rod 03 in sequence. The force is transmitted to the sample 10 to be tested, and the pressure sensor collects the pressure signal on the bottom surface of the sample 10. After the bullets are impacted, they bounce back in sequence, and the pressure signal decays to 0, and the test ends.

[0092] like Figure 8 As shown, the specific experimental results of this embodiment are as follows:

[0093] The three bullets impacted at a velocity of 16.6 m / s, with a loading frequency of approximately 870 Hz, which is about 4% lower than the natural frequency of the structural response. Two experiments were conducted under the same conditions. Figure 8 The pressure-time curves of the bottom surface of the test sample 10 are presented, with the horizontal axis representing time in milliseconds (ms) and the vertical axis representing pressure in MPa. The pressure curves from the two experiments show good repeatability. The first pressure pulse peak is 246 MPa with a pulse width of approximately 0.59 ms; the second pressure pulse peak is 390 MPa with a pulse width of approximately 0.7 ms; and the third pressure pulse peak is 472 MPa with a pulse width of approximately 0.58 ms. These three pressure peaks exhibit a continuously amplifying effect. This amplification effect occurs when the loading frequency is close to the natural frequency of the structural response.

[0094] Example 5

[0095] like Figures 1 to 5 As shown, this embodiment provides a test method for a nonlinear response amplification test device for a propellant structure under multi-pulse loading. In this embodiment, there are three bullets, including bullet A13, bullet B14 and bullet C15. All bullets are made of steel and have a mass of 0.38 kg. The three bullets are coaxial. The height difference between bullets A13 and B14 is 18 mm and 20 mm respectively.

[0096] The force transmission rod 03 is made of steel, with a diameter of 60mm and a thickness of 40mm for the end disc, and a rod diameter of 20mm. The sample to be tested 10 is a combination of polytetrafluoroethylene (PTFE) and explosive. The PTFE has a diameter of 20mm and a height of 16mm, while the explosive has a diameter of 20mm and a height of 4mm.

[0097] The specific experimental procedure is as follows:

[0098] First, the axial natural frequency of the structural response part is obtained: a finite element model of the device is established, and periodic loads of different frequencies are applied to the loaded end face of the force transmission rod 03. The maximum magnification of sample 10 under different frequency conditions is analyzed, and the first-order axial natural frequency of the structural response part is found to be approximately 910Hz.

[0099] Secondly, the frequency of the loading load is adjusted: the frequency of the loading load is determined by the impact velocity and length of bullets A13, B14 and C15, as well as the axial distance between them. The frequency of the loading load is obtained by processing the loading load using the Fourier transform method. The axial distance is adjusted by changing the height of the adjusting rings B11 and C12. The frequency of the loading load can be freely adjusted according to the requirements.

[0100] Finally, the high-pressure gas chamber valve is opened, and the high-pressure gas drives bullets A13, B14 and C15 to gradually accelerate and strike the force transmission rod 03 in sequence. The force is transmitted to the sample 10 to be tested, and the pressure sensor collects the pressure signal on the bottom surface of the sample 10. After the bullets are impacted, they bounce back in sequence, and the pressure signal decays to 0, and the test ends.

[0101] like Figure 9 As shown, the specific experimental results of this embodiment are as follows:

[0102] The three bullets impacted at a velocity of 16.6 m / s, with a loading frequency of approximately 870 Hz, about 4% lower than the natural frequency of the structural response. The three pressure pulse peaks obtained in the experiment were 222 MPa, 358 MPa, and 411 MPa, with pulse widths of 0.58 ms, 0.66 ms, and 0.55 ms, respectively, showing a continuous amplification of the pressure peaks. Even with changes to some materials in sample 10, an amplification effect can still occur when the loading frequency is close to the natural frequency of the structural response.

[0103] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-pulse loading-based nonlinear response amplification test device for a charge structure, comprising a loading section (01) and a structural response section, characterized in that, The loading part (01) includes bullet A (13), which has a large diameter end and a small diameter end. Bullet B (14) is disposed outside the small diameter end of bullet A (13), and bullet C (15) is disposed outside bullet B (14). An adjusting ring B (11) is disposed at the end of bullet B (14) near the large diameter end of bullet A (13), and an adjusting ring C (12) is disposed at the end of bullet C (15) near the large diameter end of bullet A (13). The three bullets A (13), B (14), and C (15) have the same mass; The structural response part includes a limiting block (02) and a mass block (06), and a force transmission rod (03) is provided between the limiting block (02) and the mass block (06); the limiting block (02) is provided with a loading through hole (07) and a mounting hole (09) for the force transmission rod (03); The diameter of the loading through hole (07) is smaller than the diameter of the mounting hole (09). The end of the force transmission rod (03) mounted on the limiting block (02) is provided with a limiting protrusion. The outer diameter of the limiting protrusion is larger than the outer diameter of the loading through hole (07).

2. The multi-pulse loading nonlinear response amplification test device for a charge structure according to claim 1, characterized in that, A washer (08) is provided on the force transmission rod (03) located in the mounting hole (09).

3. The multi-pulse loading nonlinear response amplification test device for a charge structure according to claim 2, characterized in that, The washer ring (08) is made of a material with a low coefficient of friction.

4. The multi-pulse loading nonlinear response amplification test device for a charge structure according to claim 3, characterized in that, The gasket (08) is made of polytetrafluoroethylene.

5. The multi-pulse loading nonlinear response amplification test device for a charge structure according to claim 1, characterized in that, The force transmission rod (03) is connected to the mass block (06) via a detachable connection assembly.

6. The multi-pulse loading nonlinear response amplification test device for a charge structure according to claim 5, characterized in that, The detachable connection assembly includes a base plate (05) mounted on the mass block (06) by screws, an outer cone (04) mounted on the base plate (05) by screws, and an inner cone (16) embedded in the outer cone (04).

7. The multi-pulse loading nonlinear response amplification test device for a charge structure according to claim 6, characterized in that, The mass block (06) is provided with a limiting groove, and the base plate (05) is provided with an installation block (17) installed in the limiting groove.

8. The multi-pulse loading nonlinear response amplification test device for a charge structure according to claim 6, characterized in that, The base plate (05) is provided with a sample (10) placement platform (18).

9. A test method for the multi-pulse loading nonlinear response amplification test device according to any one of claims 1 to 8, characterized in that, Includes the following operations: Obtain the axial natural frequency of the structural response part: Establish the finite element model of the device, apply periodic loads of different frequencies to the loaded end face of the force transmission rod (03), analyze the maximum magnification of the sample (10) under different frequency conditions, obtain the frequency-amplitude curve, and thus obtain the axial natural frequency of the structural response part. Adjusting the frequency of the loading load: The frequency of the loading load is determined by the impact velocity and length of bullets A (13), B (14) and C (15), as well as the axial distance between them. The frequency of the loading load is obtained by processing the loading load using the Fourier transform method. The axial distance is adjusted by changing the height of the adjusting ring B (11) and the adjusting ring C (12). The frequency of the loading load can be freely adjusted according to the requirements. During the test, the loading part (01) was placed inside the gun barrel. The loading part (01) was driven to move at high speed by releasing high-pressure gas and entered the loading through hole (07) of the limiting block (02). The response result of the sample (10) was obtained by the bullets A (13), B (14), and C (15) striking the end surface of the force transmission rod (03) installed at one end of the limiting block (02) in sequence.

Images