Electromagnetic launch high-speed penetration transparent soil visualization test system and method of use thereof

Abstract

The application discloses an electromagnetic ejection high-speed penetration transparent soil visualization test system and a use method thereof, and the system comprises an electromagnetic ejection launching module, a transparent soil model target module, a high-speed optical observation module, a time-space multi-dimensional synchronous triggering integrated module and a data acquisition control center. The electromagnetic ejection launching device is adopted to control the projectile to cut into the model target in a pure inertia posture, and the disturbance of high-temperature gas in the traditional gas gun launching is avoided. The transparent soil sample in the transparent soil model target module is designed through a gradient impedance distribution target and an optical matching interface, and the problems of interface reflection and instantaneous loss of transparency under an extreme strain rate are eliminated. The application provides a train of thought for solving the problems in the traditional high-speed penetration test, such as great disturbance of a power source, many blind areas of soil observation, asynchronization of physical observation and time-space, and the like, and can realize full-process controllability and fixed-point triggering of a test penetration process, and full-field transparent observation of an internal deformation field.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering dynamics and dynamic impact mechanics testing technology, specifically an electromagnetic catapult high-speed penetration transparent soil visualization test system and its usage method. Background Technology

[0002] With the deepening research on soil dynamic response under high strain rates, the safety performance evaluation of major infrastructure such as tunnels, underground utility tunnels, and defensive bunkers under high-speed impact loads has become a key scientific issue in geotechnical engineering and disaster prevention and mitigation. Traditional soil dynamic testing research mainly relies on air guns or gunpowder-driven launching devices, but existing testing techniques show obvious limitations when facing the simulation requirements of complex underground environments.

[0003] Regarding the use of power sources, traditional air cannons and gunpowder-driven devices are limited by their driving principles, resulting in high speed dispersion. The inherent defects of ) and the difficulty in Precise and continuous adjustment can be achieved within the speed range. At the same time, the high-temperature and high-pressure gas accompanying the launch process can easily cause uncontrollable disturbances to the initial flow field of penetration, which seriously affects the accurate capture of the initial impact response of the soil.

[0004] In terms of observation methods, the inherent opacity of conventional natural rock, soil, or concrete materials greatly limits the real-time observation of their internal deformation fields. Although existing X-ray phase-contrast imaging systems theoretically possess the ability to see through objects, their high dependence on synchrotron radiation sources makes the system construction and operation costs extremely high, and the requirement for extremely high temporal resolution poses a huge technical challenge to capturing data acquisition throughout the penetration process, making it difficult to popularize in conventional laboratory environments.

[0005] Regarding the extreme environmental adaptability of transparent soil tests, existing transparent soil observation models are mostly based on fused silica-mineral oil refractive index matching systems. However, when the strain rate exceeds... At that time, the instantaneous breakage of particles and severe local compaction caused by high-speed impact will cause large-scale failure of the refractive index matching zone, resulting in the observation window rapidly "losing its transparency" at the moment of penetration, making it impossible to collect continuous data on the evolution of the strain rate field inside the soil, which greatly limits the correction of the soil constitutive model under extreme loading.

[0006] In terms of system integration and timing coordination, the launch, triggering, and signal acquisition subsystems of existing test systems are often deployed independently, and each has a significant signal delay, making it difficult to achieve precise microsecond-level linkage between the various links. This problem of "spatiotemporal asynchrony" often causes experimenters to lose core data at the moment of projectile impact and the initial penetration phase, making it difficult to establish a highly reliable dynamic deformation field evolution map.

[0007] Therefore, it is of great significance to develop a transparent experimental system that can achieve precise speed control, overcome the devitrification effect under extreme strain rates, and has sub-microsecond spatiotemporal triggering and linkage capabilities. Summary of the Invention

[0008] The purpose of this invention is to provide a visualization test system for high-speed electromagnetic catapult penetration of transparent soil, including an electromagnetic catapult launch module, a transparent soil model target module, a high-speed optical observation module, a spatiotemporal multidimensional synchronous triggering integration module, and a data acquisition and control center.

[0009] The electromagnetic catapult launch module includes a gantry, a multi-stage electromagnetic coil accelerator, and a high-energy pulsed capacitor power supply. The multi-stage electromagnetic coil accelerator is suspended on the gantry. Each coil in the multi-stage electromagnetic coil accelerator is connected to the high-energy pulsed capacitor power supply, forming an independent discharge circuit. Based on the timing trigger commands sent by the data acquisition and control center, the high-energy pulsed capacitor power supply outputs pulsed current to each coil in a time-division manner. The pulsed current flows into each coil, exciting it to generate a pulsed magnetic field. This pulsed magnetic field interacts with the projectile inside the multi-stage electromagnetic coil accelerator, forming an axial electromagnetic thrust that propels the projectile forward along the axial direction of the accelerator.

[0010] The transparent soil model target module includes a transparent soil model box and a composite elastic self-closing sealing assembly. The transparent soil model box is located directly below the multi-stage electromagnetic coil accelerator. The top of the transparent soil model box is open, and the transparent soil sample is placed inside. The transparent soil sample is equipped with a composite elastic self-closing sealing assembly on its top.

[0011] The high-speed optical observation module includes a high-speed camera and a laser emitter. The high-speed optical observation module is used to acquire images of the deformation of a transparent soil sample when it is impacted by a projectile.

[0012] The spatiotemporal multidimensional synchronous triggering integrated module includes a trigger controller, a laser velocimetry probe, and a non-contact laser triggering barrier array. The laser velocimetry probe is located at the exit end of the multi-stage electromagnetic coil accelerator. The non-contact laser triggering barrier array is positioned flush with the top surface of the transparent soil sample. The trigger controller is connected to a high-energy pulse capacitor power supply, a high-speed camera, the laser velocimetry probe, and the non-contact laser triggering barrier array, respectively, and is used for calibration and verification of the test timing.

[0013] During the experiment, the initial velocity of the projectile was calculated based on the time it took for the projectile's head and tail to pass the laser velocity measuring probe and the length of the projectile. The phase difference drift was calculated based on the timing of the timing trigger command sent by the data acquisition and control center and the timing of the photoelectric blocking signal generated by the non-contact laser trigger barrier array. This phase difference was used for dynamic phase compensation of the exposure windows of the high-speed camera and the laser emitter.

[0014] Furthermore, the multi-stage electromagnetic coil accelerator includes coils, a launcher, a launcher support, and a projectile. The launcher is a hollow, rotating structure with one end closed and the other open. Several coils are sleeved around the launcher along its axial direction. The launcher support and the projectile are coaxially arranged inside the launcher. The launcher support is magnetically attached to the closed side of the launcher to fix the projectile when the high-energy pulse capacitor power supply is not activated.

[0015] Furthermore, the outer periphery of the ejector is coated with lubricant.

[0016] Furthermore, the multi-stage electromagnetic coil accelerator is suspended on the crossbeam of the gantry frame via a posture adjustment device. The posture adjustment device ensures that the axis of the multi-stage electromagnetic coil accelerator is aligned with the axis of the transparent soil model box.

[0017] Furthermore, the transparent soil sample comprises, from top to bottom, an impact-resistant compacted buffer layer, a strain energy core observation layer, and a high-energy-absorbing base.

[0018] Both the impact-resistant dense buffer layer and the strain energy core observation layer comprise solid particles and porous media. The solid particles in the impact-resistant dense buffer layer account for 42%–45% of the total volume of the buffer layer. The solid particles in the strain energy core observation layer account for 38%–42% of the total volume of the core observation layer.

[0019] Tracer particles are uniformly distributed in the strain energy core observation layer.

[0020] An optical matching isolation interface is provided between the impact-resistant dense buffer layer and the strain energy core observation layer. The optical matching isolation interface has a thickness of less than 20 mm. Flexible fluoroplastic separator membrane.

[0021] The high-energy-absorbing base comprises a porous polyurethane elastomer and a silicone rubber particle composite material, wherein the porous polyurethane elastomer has a mass fraction of 75% to 85%, and the silicone rubber particle material has a mass fraction of 15% to 25%.

[0022] Furthermore, the composite elastic self-closing sealing assembly has a double-layer structure, including an outer polyurethane sealing film and an inner self-healing gel layer.

[0023] The self-healing gel layer is a self-healing silicone coating applied to the side of the polyurethane sealing film near the transparent soil sample.

[0024] Furthermore, the transparent soil model target module also includes a vibration isolation test bench, a negative pressure regulating integrated valve, and a vacuum negative pressure pump.

[0025] The transparent soil model box is set on the vibration isolation test bench, and the transparent soil model box is equipped with a negative pressure regulating integrated valve, which is connected to a vacuum negative pressure pump.

[0026] Furthermore, the high-speed optical observation module includes three high-speed cameras and three laser emitters.

[0027] High-speed cameras and laser emitters are installed on the top of the transparent soil model box and on its two adjacent side walls.

[0028] Furthermore, when the projectile cuts into the transparent soil sample and passes through the non-contact laser-triggered barrier array, the optical signal is blocked, and the output electrical signal changes abruptly.

[0029] During the experiment, the starting reference time was the moment when the data acquisition and control center sent the timing trigger command to the high-energy pulse capacitor power supply group. The moment when the barrier array generates a transition signal using a non-contact laser trigger is the zero reference for penetration physical triggering. .calculate and Phase difference drift between Based on the phase difference drift, dynamic phase compensation is performed on the exposure windows of the high-speed camera and the laser emitter.

[0030] Another objective of this invention is to provide a method for using a high-speed electromagnetic catapult-based transparent soil penetration visualization test system, comprising the following steps:

[0031] S1, connecting the test system, including the electromagnetic catapult launch module, the transparent soil model target module, the high-speed optical observation module, the spatiotemporal multidimensional synchronous triggering integration module, and the data acquisition and control center.

[0032] S2. Prepare transparent soil samples in a transparent soil model box.

[0033] Start the negative pressure regulating integrated valve and use the vacuum negative pressure maintaining pump to degas the inside of the transparent soil model box until there are no air bubbles inside the refractive index matching liquid.

[0034] S3. Drive the posture adjustment device to make the axis of the multi-stage electromagnetic coil accelerator and the axis of the transparent soil model box lie on the same straight line.

[0035] S4. Set timing trigger commands in the data acquisition and control center to confirm the discharge time of each stage of the coil in the multi-stage electromagnetic coil accelerator.

[0036] The starting reference time is the moment when the data acquisition and control center sends the timing trigger command to the high-energy pulse capacitor power supply group. .

[0037] S5. Activate the laser emitter. Based on the timing trigger command, the high-energy pulse capacitor power supply is triggered to output pulse current, driving the projectile to accelerate in multiple stages. When the projectile enters the non-contact laser trigger barrier array, the high-speed camera is activated via the trigger controller.

[0038] During the experiment, the timing of the timing trigger command issued by the data acquisition and control center was recorded. The moment when the non-contact laser-triggered barrier array generates a transition signal. .

[0039] S6, Time-based , Calculate the time drift And through time drift The acquisition window of the high-speed camera and the pulse exposure sequence of the laser emitter are corrected.

[0040] S7. Receive and store the speckle image sequence of the entire penetration process captured by the high-speed camera through the data acquisition and control center.

[0041] S8. Based on digital image correlation algorithms, the speckle image sequence is processed to obtain a two-dimensional displacement vector field. Then, through a reprojection model, the two-dimensional displacement vector field is transformed into a three-dimensional physical coordinate system to reconstruct a three-dimensional visualization image.

[0042] S9. Based on the multi-scale adaptive optimization strategy constrained by optical flow field, the speckle image sequence is processed to obtain the displacement vector field. Then, by performing gradient analysis on the displacement vector field, a full spectrum of multi-physics field evolution, including the full-field transient strain rate cloud map and the stress wave propagation, is generated.

[0043] The technical effects of this invention are undeniable, and its beneficial effects are as follows:

[0044] A. To address the challenges of high speed dispersion and difficulty in continuous adjustment of dynamic loading devices, this experimental system completely overcomes the problem of high speed dispersion in traditional air cannons or gunpowder-driven devices by introducing a multi-stage electromagnetic coil accelerator (102) and a high-energy pulse capacitor power supply (104). The system overcomes the limitations of traditional methods, such as the limited adjustment range. Through precise control of the pulse discharge sequence via a data acquisition and control center, the system achieves continuous and accurate adjustment of the projectile's initial velocity within a wide range, significantly improving the parameter controllability and result reproduction accuracy of penetration tests under different operating conditions.

[0045] B. Addressing the challenge of observing the internal deformation field caused by the opacity of conventional soil and rock materials, this experimental system introduces transparent soil technology, enabling direct visualization of the internal mechanical response of transparent soil samples under conventional laboratory conditions. Combined with a high-speed optical observation module and the DIC algorithm, the system successfully elevates penetration dynamics testing from macroscopic waveform deduction to microscopic visualization observation, achieving a technological leap from single "point measurement" to "full-field measurement." This not only significantly reduces the construction and operation costs of the experimental system but also provides a low-threshold, high-precision technical solution for conducting microscopic evolution mechanism research on complex soil and rock dynamics in conventional laboratories.

[0046] C. Addressing the challenge of observation window failure caused by the instantaneous "loss of transparency" in transparent soil under extreme loading, this system solves the problem of large-scale failure of the refractive index matching zone due to instantaneous aggregate breakage under high strain rate impact by employing gradient structure design and the application of optically matched isolation interfaces. This design, through energy diversion in the impact-resistant dense buffer layer and stress coupling with the optically matched isolation interface, physically ensures that the core strain energy observation layer maintains high light transmittance under extreme loads, achieving continuous, high-fidelity dynamic capture of the entire process of displacement field evolution within the soil.

[0047] D. Addressing the challenge of "spatiotemporal asynchrony," this system utilizes a linkage control logic based on "command-physical" dual-reference synchronization to achieve precise coupling between optical observation timing and penetration physical timing via a non-contact laser-triggered barrier array. This technology, through real-time calculation and dynamic compensation of phase drift, ensures that the high-speed camera's imaging window accurately covers the instant the projectile contacts the target, resolving the previous problem of "data omission during core periods" caused by independent deployment of subsystems and signal delays. This provides an observational foundation for constructing a highly reliable dynamic deformation field. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the overall structural layout of the test system;

[0049] Figure 2 This is a cross-sectional view of the electromagnetic catapult launch module.

[0050] Figure 3 This is a schematic diagram of a posture adjustment device;

[0051] Figure 4 A schematic diagram of the internal gradient structure and sealing components of the transparent soil model target module;

[0052] Figure 5 Logic diagram of the spatiotemporal multidimensional synchronous triggering integrated module linkage control logic;

[0053] In the figure: gantry 101, multi-stage electromagnetic coil accelerator 102, launcher 103, high-energy pulse capacitor power supply group 104, posture adjustment device 105, projectile sabot 106, projectile body 107, transparent soil model box 201, composite elastic self-closing sealing assembly 202, transparent soil sample 203, impact-resistant dense buffer layer 204, strain energy core observation layer 205, bottom high-energy absorbing base 206, optical matching isolation interface 207, vibration isolation test bench 208, negative pressure regulating integrated valve 209, vacuum negative pressure pump 210, high-speed camera 301, laser emitter 302, laser plane 303, trigger controller 401, laser velocity probe 402, non-contact laser trigger barrier array 403, data acquisition and control center 404. Detailed Implementation

[0054] The present invention will be further described below with reference to embodiments, but it should not be construed that the scope of the present invention is limited to the following embodiments. Various substitutions and modifications made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention should be included within the scope of protection of the present invention.

[0055] Example 1:

[0056] A visualization test system for high-speed electromagnetic catapult penetration of transparent soil includes an electromagnetic catapult launch module, a transparent soil model target module, a high-speed optical observation module, a spatiotemporal multidimensional synchronous triggering integration module, and a data acquisition and control center 404.

[0057] The electromagnetic catapult launch module includes a gantry 101, a multi-stage electromagnetic coil accelerator 102, and a high-energy pulse capacitor power supply group 104. The multi-stage electromagnetic coil accelerator 102 is suspended on the gantry 101. Each coil in the multi-stage electromagnetic coil accelerator 102 is connected to the high-energy pulse capacitor power supply group 104, forming an independent discharge circuit. According to the timing trigger command sent by the data acquisition and control center 404, the high-energy pulse capacitor power supply group 104 outputs pulse current to each coil in a time-division manner. The pulse current flows into each coil, exciting the coil to generate a pulse magnetic field. The pulse magnetic field interacts with the projectile 107 inside the multi-stage electromagnetic coil accelerator 102, forming an axial electromagnetic thrust, which propels the projectile 107 forward along the axial direction of the multi-stage electromagnetic coil accelerator 102.

[0058] The transparent soil model target module includes a transparent soil model box 201 and a composite elastic self-closing sealing assembly 202. The transparent soil model box 201 is located directly below the multi-stage electromagnetic coil accelerator 102. The top of the transparent soil model box 201 is open, and a transparent soil sample 203 is placed inside the box. The top of the transparent soil sample 203 is equipped with the composite elastic self-closing sealing assembly 202.

[0059] The high-speed optical observation module includes a high-speed camera 301 and a laser emitter 302. The high-speed optical observation module is used to acquire images of the deformation of the transparent soil sample 203 when the projectile 107 impacts it.

[0060] The spatiotemporal multidimensional synchronous triggering integrated module includes a trigger controller 401, a laser velocimetry probe 402, and a non-contact laser triggering barrier array 403. The laser velocimetry probe 402 is located at the exit end of the multi-stage electromagnetic coil accelerator 102. The non-contact laser triggering barrier array 403 is positioned flush with the top surface of the transparent soil sample 203. The trigger controller 401 is connected to the high-energy pulse capacitor power supply group 104, the high-speed camera 301, the laser velocimetry probe 402, and the non-contact laser triggering barrier array 403, respectively, and is used to calibrate and set the test timing.

[0061] During the test, the initial velocity of the projectile was calculated based on the time it took for the projectile's head and tail to pass through the laser velocity measuring probe 402 and the length of the projectile 107. The phase difference drift was calculated based on the timing of the timing trigger command sent by the data acquisition and control center 404 and the timing of the photoelectric blocking signal generated by the non-contact laser trigger barrier array 403. This phase difference was used for dynamic phase compensation of the exposure windows of the high-speed camera 301 and the laser emitter 302.

[0062] Example 2:

[0063] The main structure of this embodiment is the same as that of Embodiment 1. Furthermore, the multi-stage electromagnetic coil accelerator 102 includes a coil, a launcher 103, a sabot 106, and a projectile 107.

[0064] The launcher 103 is a hollow, closed-end, and open-end rotating structure. Several coils are sleeved around the launcher 103 along its axial direction. A projectile support 106 and a projectile 107 are coaxially arranged inside the launcher 103. The projectile support 106 is magnetically attached to the closed side of the launcher 103 to fix the projectile 107 when the high-energy pulse capacitor power supply group 104 is not activated.

[0065] Before receiving a timing trigger command, the ejector 106 is rigidly constrained in its initial posture by a magnet adsorption positioning component located on the closed side of the rear of the multi-stage electromagnetic coil accelerator 102, preventing axial drift due to gravity or system micro-vibrations in the standby state. When the data acquisition and control center 404 releases a pulse drive current, the transient electromagnetic thrust generated by the electromagnetic coil is much greater than the ultimate critical restraint force of the initial positioning component, thereby achieving instantaneous unlocking and high-energy acceleration.

[0066] Example 3:

[0067] The main structure of this embodiment is the same as that of embodiment 2. Furthermore, the outer periphery of the sabot 106 is coated with lubricant to reduce friction with the outer shell of the launcher.

[0068] Example 4:

[0069] The main structure of this embodiment is the same as any one of embodiments 1 to 3. Furthermore, the multi-stage electromagnetic coil accelerator 102 is suspended on the crossbeam of the gantry frame 101 by the posture adjustment device 105.

[0070] The pose adjustment device 105 makes the axis of the multi-stage electromagnetic coil accelerator 102 and the axis of the transparent soil model box 201 lie on the same straight line.

[0071] See Figure 3 In this embodiment, the posture adjustment device 105 refers to a high-strength bolt. A square annular crossbeam is provided at the center of the top surface of the gantry 101. The top of the multi-stage electromagnetic coil accelerator 102 is located in the square annular crossbeam. A high-strength bolt is provided on each side of the square annular crossbeam. One end of the high-strength bolt passes through the square annular crossbeam and abuts against the side wall of the multi-stage electromagnetic coil accelerator 102. The position of the multi-stage electromagnetic coil accelerator 102 can be changed by adjusting the insertion length of the high-strength bolt.

[0072] Example 5:

[0073] The main structure of this embodiment is the same as any one of embodiments 1 to 4. Furthermore, the transparent soil sample 203 includes, from top to bottom, an impact-resistant compacted buffer layer 204, a strain energy core observation layer 205, and a high-energy absorption base 206.

[0074] Both the impact-resistant dense buffer layer 204 and the strain energy core observation layer 205 comprise solid particles and a porous medium. The solid particles are fused silica sand particles. The porous medium is a mixture of n-dodecane and white oil.

[0075] The solid particles in the impact-resistant dense buffer layer 204 account for 42% to 45% of the total volume of the impact-resistant dense buffer layer 204.

[0076] The volume of solid particles in the strain energy core observation layer 205 accounts for 38% to 42% of the total volume of the strain energy core observation layer 205.

[0077] Tracer particles are uniformly distributed in the strain energy core observation layer 205.

[0078] An optical matching isolation interface 207 is provided between the impact-resistant dense buffer layer 204 and the strain energy core observation layer 205. The optical matching isolation interface 207 has a thickness of less than 20 mm. Flexible fluoroplastic separator membrane.

[0079] The high-energy-absorbing base 206 comprises a porous polyurethane elastomer and a silicone rubber particle composite material, wherein the porous polyurethane elastomer has a mass fraction of 75% to 85%, and the silicone rubber particle material has a mass fraction of 15% to 25%.

[0080] Example 6:

[0081] The main structure of this embodiment is the same as any one of embodiments 1 to 5. Furthermore, the composite elastic self-closing sealing component 202 has a double-layer structure, including an outer polyurethane sealing film and an inner self-healing gel layer.

[0082] The self-healing gel layer is a self-healing silicone coating applied to the side of the polyurethane sealing film near the transparent soil sample 203.

[0083] Example 7:

[0084] The main structure of this embodiment is the same as any one of embodiments 1 to 6. Furthermore, the transparent soil model target module also includes a vibration isolation test bench 208, a negative pressure regulating integrated valve 209, and a vacuum negative pressure pump 210.

[0085] The transparent soil model box 201 is set on the vibration isolation test bench 208, and the transparent soil model box 201 is equipped with a negative pressure regulating integrated valve 209, which is connected to the vacuum negative pressure pump 210.

[0086] Example 8:

[0087] The main structure of this embodiment is the same as any one of embodiments 1 to 7. Furthermore, the high-speed optical observation module includes three high-speed cameras 301 and three laser emitters 302.

[0088] High-speed cameras 301 and laser emitters 302 are installed on the top of the transparent soil model box 201 and on the two adjacent side walls.

[0089] Example 9:

[0090] The main structure of this embodiment is the same as any one of embodiments 1 to 8. Furthermore, when the projectile 107 cuts into the transparent soil sample 203 and passes through the non-contact laser trigger barrier array 403, the optical signal is blocked and the output electrical signal changes.

[0091] During the experiment, the starting reference time was the moment when the data acquisition and control center 404 sent the timing trigger command to the high-energy pulse capacitor power supply group 104. The moment when the non-contact laser-triggered barrier array 403 generates a transition signal is the zero reference for penetrating the physical trigger. .calculate and Phase difference drift between Based on the phase difference drift, dynamic phase compensation is performed on the exposure windows of the high-speed camera 301 and the laser emitter 302, that is, the phase difference drift is... As dynamic phase feedback, the high-speed camera and laser emitter are driven to perform equal temporal displacement compensation on the preset exposure window. This ensures that when the transient physical event of the projectile penetrating the target occurs, the effective recording window of the observation system and the exposure time of the high-energy pulsed laser can be precisely aligned at the sub-microsecond level, thereby completely eliminating image timing misalignment caused by electromagnetic emission uncertainty.

[0092] Example 10:

[0093] A method for using an electromagnetic catapult high-speed penetration transparent soil visualization test system based on any one of Examples 1 to 9 includes the following steps:

[0094] S1, Connecting the test system, including the electromagnetic catapult launch module, the transparent soil model target module, the high-speed optical observation module, the spatiotemporal multidimensional synchronous triggering integration module, and the data acquisition and control center 404;

[0095] S2. Prepare transparent soil sample 203 in transparent soil model box 201;

[0096] Start the negative pressure regulating integrated valve 209, and use the vacuum negative pressure maintaining pump 209 to perform gradient degassing treatment on the inside of the transparent soil model box 201 until there are no air bubbles inside the refractive index matching liquid.

[0097] S3. Drive the posture adjustment device 105 to make the axis of the multi-stage electromagnetic coil accelerator 102 and the axis of the transparent soil model box 201 lie on the same straight line.

[0098] S4. Set timing trigger commands in the data acquisition and control center 404 to confirm the discharge time of each stage of the coil in the multi-stage electromagnetic coil accelerator 102.

[0099] The starting reference time is the moment when the data acquisition and control center 404 sends the timing trigger command to the high-energy pulse capacitor power supply group 104. ;

[0100] S5. Turn on the laser emitter 302; based on the timing trigger command, trigger the high-energy pulse capacitor power supply group 104 to output pulse current, and drive the projectile 107 to accelerate the launch in multiple stages; when the projectile 107 enters the non-contact laser trigger barrier array 403, the high-speed camera 301 is turned on through the trigger controller 401.

[0101] During the experiment, the timing trigger command issued by the data acquisition control center 404 was recorded. The non-contact laser-triggered barrier array 403 generates a transition signal at the time. ;

[0102] S6, Time-based , Calculate the time drift And through time drift The acquisition window of the high-speed camera 301 and the pulse exposure sequence of the laser emitter 302 are corrected;

[0103] S7. Receive and store the speckle image sequence of the entire penetration process captured by the high-speed camera 301 through the data acquisition and control center 404;

[0104] S8. Based on the digital image correlation algorithm, the speckle image sequence is processed to obtain a two-dimensional displacement vector field; then, through the reprojection model, the two-dimensional displacement vector field is transformed into a three-dimensional physical coordinate system to reconstruct a three-dimensional visualization image.

[0105] S9. Based on the multi-scale adaptive optimization strategy constrained by optical flow field, the speckle image sequence is processed to obtain the displacement vector field. Then, by performing gradient analysis on the displacement vector field, a full spectrum of multi-physics field evolution, including the full-field transient strain rate cloud map and the stress wave propagation, is generated.

[0106] Example 11:

[0107] The main structure of this embodiment is the same as that of embodiment 10. Further, in step S6, the data acquisition and control center uses the timing of the timing-triggered command transmission time as the base time. When the projectile reaches the transparent soil sample, a laser-triggered barrier array is used to capture the physical moment of the projectile's passage in real time. And calculate the time drift. - .

[0108] Subsequently, the data acquisition and control center based on the time drift amount Dynamically correct the acquisition window of the high-speed camera 301 and the pulse exposure sequence of the laser emitter 302:

[0109] Corrected actual trigger delay control value of high-speed camera Satisfy the following equation:

[0110]

[0111] In the formula: The original preset hardware trigger delay for the high-speed camera 301 (i.e., from the issuance of the electromagnetic discharge command) The theoretical delay until the camera opens the loop storage window); This is the time drift, which occurs when the projectile arrives with a delay. When the projectile arrives ahead of schedule, ; It is a fixed constant.

[0112] The revised version The actual on / off times of each laser emitter are:

[0113]

[0114] In the formula: , For the first The original settings for the pulse on-time and off-time of each laser emitter.

[0115] Example 12:

[0116] The main structure of this embodiment is the same as any one of embodiments 10-11. Further, in step S8, the coordinate system reprojection transformation is performed on the image sequence of each viewpoint based on the digital image correlation algorithm. The specific steps for establishing the reprojection model are as follows:

[0117] S8.1. Establish two basic coordinate systems. The first is a three-dimensional physical world coordinate system with the geometric center of the transparent soil model box as the origin. This coordinate system is used to uniquely describe arbitrary speckles within transparent soil. Spatial location.

[0118] The second is the two-dimensional sensor pixel coordinate system of each camera itself. Used to record the pixel positions of speckles on an image. .

[0119] S8.2. Calibrate the camera to obtain the... intrinsic parameter matrix of a camera and the rotation matrix relative to the world coordinate system. Translation vector .

[0120] In the ideal case where refraction is negligible Transformed to the first through rigid body transformation In the three-dimensional camera coordinate system of the camera, the ideal camera coordinates are obtained. .

[0121] Substituting the ideal camera coordinates into the projection formula of the intrinsic parameter matrix, the ideal pixel coordinates are calculated. .

[0122] S8.3. Based on the actual optical path, establish the reverse ray;

[0123] The actual optical path is as follows: the light emitted by the laser illuminates the speckled pattern inside the transparent soil. The speckled light undergoes diffuse reflection, and the reflected light passes sequentially through the porous medium, the model box, and the air layer before finally entering the camera's optical center for imaging.

[0124] To establish the mapping relationship from image to object point, a reverse optical path is adopted: it is assumed that a ray is virtually emitted from the optical center of the camera along the imaging direction, and this ray travels in reverse through the air, the model box, and the porous medium before reaching the speckle. .

[0125] According to Snell's law, the optical path satisfies the following at each interface:

[0126]

[0127] In the formula: , , These are the refractive indices of the air layer, the model box, and the porous medium, respectively. The angle of incidence is the glass window wall of the model box; , These are the refraction angles of the glass window wall and the porous medium of the model box, respectively.

[0128] S8.4 Calculate the spatial offset of light rays due to refraction based on the geometric thickness of each medium layer. Offset The calculation formula is:

[0129]

[0130] In the formula: For the thickness of the model box; For scattered spots The vertical distance to the inner wall of the model box glass; and These are the unit direction vectors of light rays projected onto the interface normal plane in the corresponding medium layer.

[0131] S8.5, Based on offset Calculate the predicted camera coordinates corresponding to the actual light rays. ;

[0132] Predict camera coordinates Substituting into the projection formula of the intrinsic parameter matrix, we obtain the predicted pixel coordinates of the speckle after refraction. .

[0133] S8.6. Based on the measured pixel coordinates and the predicted pixel coordinates, construct the reprojection error function; reprojection error function The expression is:

[0134]

[0135] In the formula: For scattered spots in the first The measured pixel coordinates corresponding to the image from the camera; Indicates the first Under the camera The relevant refractive offset.

[0136] because Depends on Nonlinear relationship ( , , , All (Changes), therefore, least squares iterative solution is used. The iteration terminates when the error is less than a preset threshold or when the maximum number of iterations is reached. This refers to the actual three-dimensional coordinates of the speckle in the physical world coordinate system.

[0137] Example 13:

[0138] The main structure of this embodiment is the same as any one of embodiments 10 to 12. Furthermore, in step S9, the process of processing the speckle image sequence includes the following steps:

[0139] S9.1. Perform stepwise downsampling on the speckle image sequence to construct an L-layer Gaussian image pyramid from large to small size, resulting in L layers of scaled image data with different resolutions; the large and small sizes refer to the image resolution and the overall pixel size, with higher resolution corresponding to a larger image size and lower resolution corresponding to a smaller image size.

[0140] In the L-layer Gaussian image, layer 0 is the unprocessed raw speckle image, and layer 1 is the unprocessed raw speckle image. The dimensions of the speckle image are both the first and second layers. -1 / 2 of the first floor;

[0141] S9.2, Select the first Two consecutive speckle images in a layer image and As the object to be processed;

[0142] Based on the Horn-Schunck energy functional, the solution is obtained for the object being processed. Dense optical flow field of the layer ;

[0143] The Horn-Schunck energy functional The expression is:

[0144]

[0145] In the formula: , Each pixel is located at , Displacement in the direction; , , Image grayscale pairs , , The partial derivatives; This is the optical flow smoothing coefficient;

[0146] S9.3, based on the first Dense optical flow field Spatial gradient tensor Calculate the first The Frobenius norm of each pixel in the layer; the norm is used to characterize the severity of local deformation; the formula for calculating the norm is:

[0147]

[0148] S9.4 Setting dynamic threshold ;Will > The pixels marked as high strain gradient regions are the other pixels marked as low deformation background regions.

[0149] Dynamic threshold The calculation formula is:

[0150]

[0151] In the formula: , The first Norm of all pixels in the layer image The mean and standard deviation, This is an empirical coefficient;

[0152] S9.5. Determine the sub-region size and calculation step size based on the location of the pixel;

[0153] Specifically, the sub-region size refers to the side length (in pixels) of a local square image region to be matched, centered at the calculation point; the calculation step size refers to the pixel distance between two adjacent calculation points. The specific configuration parameter range and adaptive determination mechanism are as follows:

[0154] For regions with high strain gradients, a small-sized sub-region paired with a small computational step size is used to capture the extreme nonlinear geometric deformation around the projectile tip and the stress wave front. The side length of the small-sized sub-region is... The range is set to 11×11 pixels ≤ ≤21×21 pixels, preferably 15×15 pixels; small calculation step size The range is set to 1 pixel ≤ <3 pixels, preferably 1 pixel.

[0155] For the low-deformation background region, in order to suppress high-frequency noise and improve the solution efficiency in the small displacement region, a large-size sub-region is used with a large calculation step size. The side length of the large-size sub-region... The range is set to 31×31 pixels ≤ <41×41 pixels, preferably 31×31 pixels; the range of large calculation step size is set to 7 pixels ≤ ≤11 pixels, preferably 11 pixels.

[0156] To prevent numerical shear distortion at the displacement field boundary caused by abrupt changes in the subregion and step size, the subregion size in the transition region between the high strain gradient region and the low deformation background region is controlled. With calculation step size The Frobenius norm-based linear interpolation method was used to determine it;

[0157] S9.6. Based on the calculation step size, confirm the calculation point (center position of the sub-region), and extract the sub-region image of the current frame with each calculation point as the center. Sub-region image of the next frame The deformation within the sub-region satisfies the first-order shape function, and the coordinate correspondence is as follows:

[0158]

[0159]

[0160] In the formula: ( ) represents the displacement component at the center of the sub-region; , The coordinate offset of the pixel within the sub-region is equivalent to the center.

[0161] S9.7 Substitute the correspondence from step S9.6 into the objective function and iteratively solve the objective function to obtain the optimal shape function parameter vector. ;

[0162] The expression for the objective function is:

[0163]

[0164]

[0165] In the formula: Let be the vector of shape function parameters to be optimized; According to The gray level of the target sub-region is calculated through the coordinate transformation in step S9.6;

[0166] Will As the local displacement vector at each calculation point; the set of local displacement vectors at all calculation points constitutes the local displacement field. ;

[0167] The criterion for iterative convergence is: when the norm of the change in the shape function parameter vector... < Or reach the maximum number of iterations;

[0168] S9.8, the first All calculation points within a layer are considered as a single, unified field. Construct a global energy functional; the global energy functional The function expression is:

[0169]

[0170]

[0171]

[0172]

[0173] In the formula: For data items; For smoothing terms; It is a priori; , For regularization parameters;

[0174] S9.9, the steps in S9.7 and step S9.2 Substituting the global energy functional from step S9.8, and using the primal-dual algorithm, the global energy functional is iteratively solved to obtain the th... Full-field displacement vector field of the layer ;

[0175] The criteria for iterative convergence are: Or it may reach the maximum number of iterations. For the first The full-field displacement vector field obtained from the next iteration.

[0176] like =0, output As the global displacement vector field, otherwise, Upsampling by a factor of 10, as the first -1 layer iterative solution of the initial displacement field, and let = -1, return to step S9.2.

[0177] Example 14:

[0178] The main structure of this embodiment is the same as any one of embodiments 1 to 13. Furthermore, an electromagnetic catapult high-speed penetration transparent soil visualization test system includes an electromagnetic catapult launch module, a transparent soil model target module, a high-speed optical observation module, and a spatiotemporal multidimensional synchronous triggering integration module.

[0179] The electromagnetic catapult launch module includes a high-rigidity gantry 101 for suspending the electromagnetic acceleration system. The electromagnetic acceleration system includes a multi-stage electromagnetic coil accelerator 102, an integrated projectile-sater launcher 103, and a high-energy pulse capacitor power supply 104.

[0180] The end of the multi-stage electromagnetic coil accelerator 102 is mounted on the crossbeam of the high-rigidity gantry 101 via a pose adjustment device 105, and its position can be adjusted with multiple degrees of freedom in three-dimensional space to achieve precise adjustment of the spatial axis.

[0181] The high-energy pulse capacitor power supply 104 is connected to the multi-stage electromagnetic coil accelerator 102 and is used to output high-amplitude pulse current to the multi-stage electromagnetic coil accelerator 102.

[0182] The multi-stage electromagnetic coil accelerator 102 is connected to the projectile-saucer integrated launcher 103. By outputting a high-amplitude pulsed magnetic field, it accelerates the projectile in the projectile-saucer integrated launcher 103 in multiple stages and converts the pulsed magnetic field energy established in the multi-stage electromagnetic coil accelerator 102 into the kinetic energy of the projectile, thereby exciting the projectile.

[0183] The sabot is closely attached to the internal cavity of the projectile-sabot integrated launcher 103, and the gap is filled with lubricating fluid.

[0184] The transparent soil model target module includes a transparent soil model box 201, with a composite elastic self-closing sealing component 202 sealed at the top of the liquid surface.

[0185] The composite elastic self-closing sealing component 202 adopts a double-layer structure. The outer layer is a polymer sealing film, specifically polyurethane with a high elastic recovery coefficient, to prevent leakage of pore fluid in transparent soil under overflow pressure. The inner layer is a self-healing gel layer, specifically coated with high-viscosity self-healing silicone, which uses the lubrication effect to reduce the penetration resistance of the projectile and fill tiny physical gaps, maintaining the vacuum negative pressure environment inside the model box, and achieving precise control of the airtightness of the transparent soil model box 201 throughout the test.

[0186] The transparent soil model box 201 is filled with a transparent soil sample 203 with refractive index matching. The transparent soil sample 203 uses fused silica sand solid particles as aggregate, and the pore medium is a refractive index matching liquid, which is a mixture of n-dodecane and white oil.

[0187] The transparent soil sample 203 contains, from top to bottom, a gradient distribution of an impact-resistant dense buffer layer 204, a strain energy core observation layer 205, and a bottom high-energy absorbing base 206.

[0188] The impact-resistant dense buffer layer 204 uses fused silica sand solid particles with a volume ratio of 30% to 40%. It is formed into a continuous transparent medium through high-pressure pre-compression and solidification. This medium is used to guide the deflection of the penetrating flow field at the moment of contact with the projectile and effectively attenuate the peak pressure of the incident shock wave.

[0189] The volume ratio of solid fused silica sand particles used in the strain energy core observation layer 205 is less than 30%, and tracer particles are uniformly distributed in it to capture the vector evolution of displacement field and dynamic development of shear bands in the strain energy core observation layer 205 during the projectile's passage through high-speed optical observation.

[0190] An optically matched isolation interface 207 is used to isolate the two layers at the interface between the impact-resistant dense buffer layer 204 and the strain energy core observation layer 205. This optically matched isolation interface 207 has a thickness of less than 20 mm. The high-transmittance flexible fluoroplastic isolation membrane can block the mutual penetration of two layers of organic solvent molecules without interfering with image acquisition during the experiment.

[0191] The high-energy-absorbing base 206 is composed of a porous polyurethane elastomer and a high-damping silicone rubber particle composite material, which can absorb and dissipate the remaining kinetic energy at the end of the projectile penetration, prevent the shock wave from generating reflected stress waves at the bottom of the transparent soil model box 201, and ensure the one-dimensionality of the stress state inside the transparent soil sample 203 and the accuracy of stress wave propagation throughout the penetration process.

[0192] The transparent soil model target module also includes a vibration isolation test bench 208, which is arranged below the transparent soil model box 201 to support the transparent soil model box 201.

[0193] The transparent soil model target module also includes a negative pressure regulating integrated valve 209 and a vacuum negative pressure pump 210. The negative pressure regulating integrated valve 209 is connected to the transparent soil model box 201, and the gas exchange in the transparent soil model box 201 can be controlled by controlling the opening and closing of the valve. The vacuum negative pressure pump 210 is connected to the negative pressure regulating integrated valve 209.

[0194] The high-speed optical observation module includes three orthogonally arranged high-speed cameras 301 and three laser emitters 302. The surface laser emitted by the laser emitters 302 forms a uniformly thick laser plane 303 with a thickness of 0.5 mm. The high-speed cameras 301 and laser emitters 302 are arranged coaxially to ensure that the laser plane 303 generated by the laser emitters does not interfere with the image acquisition of the high-speed cameras 301.

[0195] The spatiotemporal multidimensional synchronous triggering integrated module includes a trigger controller 401, a laser velocity probe 402, a non-contact laser triggering barrier array 403, and a data acquisition and control center 404. The trigger controller 401 is connected to a high-energy pulse capacitor power supply group 104, a high-speed camera 301, the laser velocity probe 402, and the non-contact laser triggering barrier array 403, respectively, for calibration and verification of the test timing. The output timing of the high-energy pulse capacitor power supply group 104 is used as the test zero timing during the test. The laser velocity probe 402 is installed at the exit end of the projectile-satellite integrated launcher 103, and the initial velocity of the projectile is measured by calibrating the projectile length and the duration of the signal change acquired by the laser velocity probe 402. The initial velocity of the projectile is calculated using the following formula:

[0196]

[0197] in: Indicates the initial velocity of the projectile. Indicates the length of the projectile. This indicates the moment when the signal acquired by the laser velocimetry probe 402 at time zero of the experiment undergoes a sudden change. This indicates the time at which the signal acquired by the laser velocity measuring probe 402 at moment zero of the experiment is restored. The laser velocity measuring probe 402 generates a first trigger marker and records the time when it detects the projectile's initial contact with the laser plane. When the projectile is detected to have completely detached from the laser plane, a second trigger marker is generated and the time is recorded. After the second trigger marker is generated, the laser velocity probe 402 transmits the recorded information to the data acquisition and control center 404 in real time.

[0198] The plane defined by the non-contact laser-triggered barrier array 403 is flush with the upper surface of the impact-resistant dense buffer layer 204. When the projectile cuts into the planar impact-resistant dense buffer layer 204 at high speed, the photoelectric conversion voltage signal will experience a momentary jump due to the blocking of the laser barrier. The photoelectric blocking signal generated by the non-contact laser-triggered barrier array 403 is used as the physical contact zero reference. .

[0199] The data acquisition and control center 404 is connected to the high-energy pulse capacitor power supply group 104, the vacuum negative pressure pump 210, the high-speed camera 301, the trigger controller 401, the laser velocity probe 402, and the non-contact laser trigger barrier array 403.

[0200] The data acquisition and control center 404 can realize custom arbitrary waveforms, generate global timing signals, transmit pulse commands to the high-energy pulse capacitor power supply group 104, and discharge the multi-stage electromagnetic coil accelerator 102 through the high-energy pulse capacitor power supply group 104, thereby indirectly controlling the magnetic field in the multi-stage electromagnetic coil accelerator 102, thus realizing precise control of the electromagnetic drive of the projectile and its initial velocity; in addition, the data acquisition and control center 404 can realize the degassing treatment of the transparent soil sample 203 by controlling the opening of the vacuum negative pressure pump 210 and monitoring the real-time air pressure in the transparent soil model box 201, thereby realizing the preparation of the transparent soil sample 203.

[0201] Furthermore, the transparent soil model target module adopts an anti-devitrification gradient structure design. The transparent soil sample 203 is divided from top to bottom according to the direction of impact energy propagation: an impact-resistant dense buffer layer 204, a strain energy core observation layer 205, and a bottom high-energy absorbing base 206. Among them, the impact-resistant dense buffer layer 204 is used to disperse the impact kinetic energy at the moment of high-speed penetration of the projectile and prevent refractive index mismatch caused by local overload.

[0202] Furthermore, the electromagnetic catapult launch module adopts a "spatial multi-dimensional attitude adjustment - unconstrained inertial coupling launch" architecture. The electromagnetic catapult launch module is suspended and installed via a high-rigidity gantry 101, which is equipped with an attitude adjustment device 105 for three-dimensional spatial translation and axis tilt adjustment of the electromagnetic acceleration system. An unconstrained inertial flight section extends between the electromagnetic acceleration system's exit end and the transparent soil model box 201. This unconstrained inertial flight section is used to decouple micro-vibration noise during the electromagnetic acceleration process, ensuring that the integrated launcher 103 (projectile-satellite integrated launcher) vertically cuts into the transparent soil sample 203 with a purely inertial trajectory.

[0203] Furthermore, the high-speed optical observation module is equipped with an "orthogonal composite multi-view imaging" system. The three high-speed cameras 301 and three laser emitters 302 are arranged in a spatially orthogonal complementary manner via a connecting bracket. The system integrates time-division multiplexing illumination control logic. This system divides the single-frame sampling period into three non-overlapping sub-time slots with effective exposure windows at the microsecond level. These are triggered sequentially in a preset order by the trigger controller 401: the first group triggers the high-speed camera and laser on one side, the second group triggers the high-speed camera and laser on the other side, and the third group triggers the top high-speed camera and laser from above. The dead zones recorded by the complementary blanking images between each group enable dynamic capture of the optical flow field from all directions and multiple perspectives during the projectile penetration process, avoiding blind spots caused by projectile obstruction.

[0204] Furthermore, the spatiotemporal multidimensional synchronization triggering integrated module adopts a linkage control logic based on "command-physical" dual-reference synchronization. The synchronization control logic includes: using the moment when the data acquisition control center 404 sends a high-energy pulse output command to the high-energy pulse capacitor power supply group 104 as the logic starting reference for the test system. The moment when the photoelectric blocking signal is generated by the non-contact laser-triggered barrier array 403 is used as the zero reference for physical triggering of penetration. The data acquisition and control center 404 has a built-in sub-microsecond timing logic operation unit for real-time calculation. and The phase difference drift between the two is calculated, and dynamic phase compensation is performed on the exposure windows of the high-speed camera 301 and the laser emitter 302 based on the phase difference, so as to achieve precise coupling between the optical observation timing and the penetration physical timing.

[0205] Furthermore, the linkage control logic further includes a multi-level time window segmentation mechanism: the data acquisition control center 404 divides the entire test process into three logical time slices: "pulse acceleration phase," "ballistic inertial flight phase," and "penetration deformation observation phase." Specifically, in the "pulse acceleration phase," a logical starting reference is used... As the driving core, the multi-stage electromagnetic coil accelerator 102 is subjected to time-segmented pulse excitation via the trigger controller 401; during the "penetration deformation observation stage", the zero reference is based on the penetration physical trigger. A relative time axis is established, and a cyclic pulse sampling command is sent to the high-speed camera 301 to ensure that the optical imaging observation window completely covers the entire process of the projectile penetrating the target surface.

[0206] A method for using the above-mentioned electromagnetic catapult high-speed penetration transparent soil visualization test system includes the following steps:

[0207] S1. Preparation of High-Transparency Gradient Target: Transparent soil solid particles (fused silica sand) with refractive index matching characteristics, along with a refractive index matching liquid (a mixture of n-dodecane and white oil) and tracer speckle particles, are layered and filled into a transparent soil model box 201 according to a preset density gradient. At the test temperature, the refractive index difference between the transparent soil solid particles and the refractive index matching liquid is controlled within ±0.002, ensuring that the transparent soil sample 203 is completely transparent. The negative pressure regulating integrated valve 209 is activated, and the vacuum negative pressure maintaining pump 209 performs gradient degassing treatment inside the model box 201 until no microbubbles remain inside the fluid, the negative pressure inside the transparent soil model box 201 is stable, and the uniformity of the refractive index distribution of the sample is verified using a laser sheet optical plane 303.

[0208] S2. Spatial multi-dimensional pose linkage centering calibration: By driving the pose adjustment device 105 of the high-rigidity gantry 101, the axial attitude of the multi-stage electromagnetic coil accelerator 102 is adjusted. The coaxiality of the launch axis and the geometric center axis of the transparent soil model box 201 is verified by a high-precision laser tracker. After centering is completed, the pose is locked to ensure that the trajectory deviation of the unconstrained inertial flight segment meets the micron-level correction accuracy.

[0209] S3. Spatiotemporal pulse calibration based on dual-reference logic: using the data acquisition and control center 404 to preset the system logic starting reference. The integrated projectile-satellite launcher 103 was pre-tested, and the response time sequence of the laser velocity probe 402 was collected. The penetration physical trigger zero reference was captured by the non-contact laser trigger barrier array 403. Calculate and update the phase difference drift to generate a high strain rate environment. and The time mapping table is used to provide a data basis for setting coil parameters and timing instructions of the data acquisition control center 404 for specific transparent soil tests;

[0210] S4. Electromagnetic Drive-Unconstrained Inertial Cooperative Penetration: The laser emitter 302 is activated. The high-energy pulse capacitor power supply 104 is triggered, executing multi-stage stepped discharge logic to drive the projectile to complete electromagnetic acceleration. This causes the projectile to separate from the sabot at the point where the projectile cross-section changes, detaching from the multi-stage electromagnetic coil accelerator 102 exit and entering unconstrained inertial flight. The trigger controller 401 is activated based on the physical zero moment. The high-speed camera 301 is activated for simultaneous exposure, enabling instantaneous physical field capture of the projectile's penetration process.

[0211] S5. Synchronous Acquisition of Multi-Source, Multi-View Optical Flow Field: Through time-division multiplexing control logic, the high-speed camera 301 is driven to perform exposure sampling. Using an orthogonal composite multi-view imaging component, the speckle displacement field generated by the penetration of the projectile inside the transparent soil sample 203 is acquired in a multi-dimensional sequence, and the optical signals are synchronously transmitted to the data acquisition control center 404 for real-time buffering.

[0212] S7. Deformation Field Solution Based on Spatiotemporal Alignment and Optical Flow Field Constraints: The Digital Image Correlation (DIC) algorithm is used to perform coordinate system reprojection transformation on the image sequences from each viewpoint to achieve spatial domain alignment and matching. A multi-scale adaptive optimization strategy based on optical flow field constraints is introduced to refine the local sub-regions for the high strain gradient region around the projectile. Finally, the transient strain rate cloud map, displacement vector field, and dynamic stress wave propagation evolution characteristics of the soil are inverted and constructed.

[0213] Example 15:

[0214] The main structure of this embodiment is the same as any one of embodiments 1 to 14. Further, see [link to embodiment 1]. Figure 1 This embodiment provides an electromagnetic catapult high-speed penetration visualization test system for transparent soil, including an electromagnetic catapult launch module, a transparent soil model target module, a high-speed optical observation module, and a spatiotemporal multidimensional synchronous triggering integration module.

[0215] The electromagnetic catapult launch module includes a gantry 101, a multi-stage electromagnetic coil accelerator 102, an integrated launcher 103 consisting of a projectile and a sabot, a high-energy pulse capacitor power supply 104, and an attitude adjustment device 105.

[0216] The gantry 101 provides high-rigidity support for the entire launching device.

[0217] The multi-stage electromagnetic coil accelerator 102 is mounted on the crossbeam of the high-rigidity gantry 101 via an attitude adjustment device 105 to achieve precise positioning of the launch axis.

[0218] The projectile-slinger integrated launcher 103 is positioned within the axis of the multi-stage electromagnetic coil accelerator 102.

[0219] The high-energy pulse capacitor power supply 104 is connected to the multi-stage electromagnetic coil accelerator 102. The data acquisition and control center 404 triggers the discharge according to the preset sequence, and uses the Lorentz force generated by the induced eddy current to drive the projectile to accelerate.

[0220] The transparent soil model target module includes a transparent soil model box 201, a composite elastic self-closing sealing component 202, a transparent soil sample 203, an impact-resistant dense buffer layer 204, a strain energy core observation layer 205, a bottom high-energy absorbing base 206, and an optical matching isolation interface 207.

[0221] The transparent soil model box 201 is filled with a transparent soil sample 203.

[0222] The transparent soil sample 203 is sealed with a composite elastic self-closing sealing component 202.

[0223] The composite elastic self-closing sealing component 202 maintains a vacuum negative pressure environment through a polymer sealing membrane and a self-healing gel layer.

[0224] The transparent soil model box 201 is filled with a transparent soil sample 203 with a matching refractive index, and the impact-resistant dense buffer layer 204, the strain energy core observation layer 205, and the bottom high-energy absorption base 206 are arranged in a gradient from top to bottom.

[0225] The interface between the impact-resistant dense buffer layer 204 and the strain energy core observation layer 205 adopts an optically matched isolation interface 207 with a thickness of less than 20μm to block the diffusion of organic media in each layer and ensure the consistency of optical refractive index.

[0226] The high-energy-absorbing base 206 absorbs and dissipates the remaining kinetic energy at the penetration end of the projectile.

[0227] The transparent soil model target module integrates a vacuum negative pressure adjustment component, including a negative pressure adjustment integrated valve 209 and a vacuum negative pressure pump 210. The transparent soil sample 203 can be prepared through the negative pressure adjustment integrated valve 209 and the vacuum negative pressure pump 210.

[0228] The high-speed optical observation module includes three high-speed cameras 301, three laser emitters 302, and a laser plane 303. The three high-speed cameras 301 are arranged orthogonally around the transparent soil model box 201. The three laser emitters are coaxially mounted with the high-speed cameras 301 to generate a flat laser plane 303. The laser plane 303 forms a thin-section speckle field inside the transparent soil sample 203. The high-speed cameras 301 track the displacement of tracer particles and the evolution of shear bands inside the transparent soil in real time using the DIC algorithm.

[0229] The spatiotemporal multidimensional synchronous triggering integrated module includes a trigger controller 401, a laser velocity probe 402, a non-contact laser triggering barrier array 403, and a data acquisition and control center 404.

[0230] The laser velocity measuring probe 402 is installed at the exit end of the projectile-satellite integrated launcher 103 and is used to measure the initial velocity of the projectile.

[0231] The plane defined by the non-contact laser-triggered barrier array 403 is flush with the upper surface of the impact-resistant dense buffer layer 204. When the projectile cuts in at high speed, a photoelectric blocking signal is generated, which serves as the physical contact zero reference. The timing of the high-energy pulse output command sent from the data acquisition and control center 404 to the high-energy pulse capacitor power supply group 104 is used as the logical starting reference of the test system. .

[0232] The data acquisition and control center 404 has a built-in sub-microsecond timing logic operation unit for real-time calculation. and The phase difference drift between the two is calculated, and dynamic phase compensation is applied to the exposure window of the high-speed camera 301 to achieve precise coupling between the optical observation timing and the penetration physical timing.

[0233] Furthermore, the transparent soil sample 203 comprises solid particles and pore liquid; the solid particles are fused silica sand; the pore liquid is a mixture of n-dodecane and white oil, the refractive index of which is consistent with that of the solid particles.

[0234] The transparent soil sample 203 is configured from top to bottom according to the strain energy distribution gradient, consisting of an impact-resistant dense buffer layer 204, a strain energy core observation layer 205, and a bottom high-energy absorption base 206.

[0235] The impact-resistant compacted buffer layer 204 and the strain energy core observation layer 205 have different aggregate volume fraction settings. The impact-resistant compacted buffer layer 204 has an aggregate volume fraction of 30% to 40% to provide high compressive stiffness; the strain energy core observation layer 205 has an aggregate volume fraction of less than 30% to maximize image correlation.

[0236] At the interface between the impact-resistant dense buffer layer 204 and the strain energy core observation layer 205, by laying a layer with a thickness of less than 20 mm... The optical matching isolation interface transforms the discrete particle contact under impact load into continuous stress transmission, effectively avoiding the instantaneous "de-vitrification" and light refraction shift caused by direct collision of aggregates, and ensuring the spatial geometric fidelity of DIC acquired data.

[0237] Furthermore, the data acquisition and control center 404 employs a multi-stage stepped pulse control strategy when controlling the high-energy pulse capacitor power supply group 104 to discharge. By issuing time-segmented trigger commands to the high-energy pulse capacitor power supply group 104 through the data acquisition and control center 404, the magnetic field establishment time and current amplitude of each stage of the coils in the multi-stage electromagnetic coil accelerator 102 are precisely controlled. This strategy ensures that the electromagnetic force experienced by the projectile during acceleration is dynamically matched with the projectile's trajectory, guaranteeing that the projectile reaches the preset high speed while effectively suppressing vibration interference at the end of acceleration, thereby ensuring the attitude stability of the projectile when entering the unconstrained inertial flight phase.

[0238] Furthermore, the spatiotemporal multidimensional synchronous triggering integrated module is equipped with a sub-microsecond-level timing logic operation unit. This unit is used to acquire in real time the discharge command time of the high-energy pulse capacitor power supply group 104 and the photoelectric blocking signal fed back by the non-contact laser triggering barrier array 403. The operation unit calculates and updates the system logic starting reference in real time. With physical contact zero reference The phase difference drift between the two phases is calculated, and dynamic phase compensation is performed on the imaging window of the high-speed camera 301 based on this drift to ensure precise coupling between the optical observation timing and the penetration physical timing, thereby realizing the visualization and quantitative analysis of the entire process of projectile penetration.

[0239] Furthermore, a testing method based on the above system includes the following steps:

[0240] 1) Transparent soil solid particles (fused silica sand), refractive index matching liquid (a mixture of n-dodecane and white oil), and tracer speckle particles are layered and filled into the transparent soil model box 201 according to a preset density gradient. By changing the composition characteristics of the refractive index matching liquid, the refractive index difference between it and the solid particles is maintained at a certain level at the test temperature. The process is repeated to make the transparent soil sample 203 completely transparent. The negative pressure regulating integrated valve 209 is activated, and the vacuum negative pressure maintaining pump 210 performs multi-stage gradient degassing treatment inside the model box 201 until there are no microbubbles left inside the fluid, ensuring that the negative pressure inside the transparent soil model box 201 is constant. The uniformity of the refractive index distribution of the sample is then finally verified using the laser sheet optical plane 303.

[0241] 2) The axial attitude of the multi-stage electromagnetic coil accelerator 102 is adjusted in real time through the attitude adjustment device 105 of the high-rigidity gantry 101. The coaxiality of the launch axis and the geometric center axis of the transparent soil model box 201 is checked, and the actuator is locked after the alignment is completed to ensure that the trajectory deviation of the unconstrained inertial flight segment meets the correction accuracy requirements.

[0242] 3) The system logic starting reference is preset using the data acquisition and control center 404. The integrated projectile-satellite launcher 103 is driven to perform a low-pressure, no-load pre-test, accurately acquiring the response time sequence of the laser velocity probe 402, and simultaneously acquiring the penetration physical trigger zero reference through the non-contact laser trigger barrier array 403. By calculating and updating the phase difference drift between the two, a precise trigger mapping relationship suitable for high strain rate environments is established, eliminating the influence of system circuit delay.

[0243] 4) The laser emitter 302 is activated, triggering the high-energy pulse capacitor power supply group 104 to execute multi-stage stepped discharge logic. This drives the projectile to accelerate within the multi-stage electromagnetic coil accelerator 102. After the projectile leaves the exit and enters the unconstrained inertial flight phase, the sabot is automatically triggered to disintegrate. Simultaneously, the data acquisition and control center 404 transmits a linkage exposure command to the high-speed camera 301 based on the physical zero moment, ensuring that the optical recording system enters the full-field physical field capture state the instant the projectile contacts the target surface.

[0244] 5) Based on time-division multiplexing control logic, three high-speed cameras 301 are driven to perform high-speed sampling at a preset frame rate. Using an orthogonal composite multi-view imaging component, the speckle displacement field inside the transparent soil sample 203 excited by the projectile penetration is acquired in a multi-dimensional sequence, and the optical signals are synchronously transmitted to the data acquisition control center 404 for real-time data buffering and storage.

[0245] 6) The DIC algorithm is employed to perform rigorous coordinate system reprojection transformation on the image sequences from each viewpoint, achieving precise alignment and matching in the spatial domain. A multi-scale adaptive optimization strategy based on optical flow field constraints is introduced, focusing on local sub-region refinement calculations for the high strain gradient region around the projectile. Through the above calculation process, the evolution characteristics of the transient strain rate cloud map, displacement vector field, and dynamic stress wave propagation within the soil are finally inverted and constructed, enabling visualization and analysis of the entire penetration process of the experiment.

[0246] Example 16:

[0247] The main structure of this embodiment is the same as any one of embodiments 1 to 14. Furthermore, the purpose of this invention is to overcome the shortcomings of the prior art and provide an electromagnetic catapult high-speed penetration transparent soil visualization test system and method. It aims to solve the technical problems in existing high-speed penetration tests, such as large initial velocity dispersion of the loading power source, failure of refractive index matching (de-penetration) of transparent soil samples under extreme strain rates, asynchronous timing of the triggering of each subsystem of the system, and loss of initial penetration data when the projectile touches the target. It achieves accurate quantitative observation of the deformation, strain and displacement evolution process of the entire field of high strain rate penetration inside the soil.

[0248] The technical solution adopted to achieve the purpose of this invention is as follows: an electromagnetic catapult high-speed penetration transparent soil visualization test system and method, including an electromagnetic catapult launch module, a transparent soil model target module, a high-speed optical observation module, and a spatiotemporal multidimensional synchronous triggering integration module.

[0249] The electromagnetic catapult launch module adopts a "spatial multi-dimensional attitude adjustment-unconstrained inertial coupling launch" architecture, including a high-rigidity gantry 101 and a multi-stage electromagnetic coil accelerator 102 suspended on the high-rigidity gantry 101. The multi-stage electromagnetic coil accelerator 102 is mounted on the crossbeam of the high-rigidity gantry 101 via an attitude adjustment device 105, possessing three-dimensional spatial translation and axis tilt adjustment capabilities. The electromagnetic catapult launch module also includes a projectile-slinger integrated launcher 103 and a high-energy pulse capacitor power supply group 104. The high-energy pulse capacitor power supply group 104 is connected to the multi-stage electromagnetic coil accelerator 102 and is used to output high-energy pulses to the multi-stage electromagnetic coil accelerator 102. An unconstrained inertial flight section is provided between the outlet of the multi-stage electromagnetic coil accelerator 102 and the transparent soil model box 201. This section is used to decouple the micro-vibration noise during the electromagnetic acceleration process, ensuring that the projectile-slinger integrated launcher 103 penetrates accurately along the vertical axis with a purely inertial attitude.

[0250] The transparent soil model target module adopts a gradient structure design that resists depermeability under high strain rate penetration. The transparent soil model target module includes a transparent soil model box 201, with a composite elastic self-closing sealing component 202 sealed at the top of the liquid surface.

[0251] The composite elastic self-closing sealing component 202 achieves physical closure at the moment of penetration of the projectile through a polymer sealing film and a self-healing gel layer, maintaining a vacuum negative pressure environment.

[0252] The transparent soil model box 201 is filled with a transparent soil sample 203 with a matching refractive index, and the impact-resistant dense buffer layer 204, the strain energy core observation layer 205, and the bottom high-energy absorption base 206 are arranged in a gradient from top to bottom.

[0253] The interface between the impact-resistant dense buffer layer 204 and the strain energy core observation layer 205 uses a thickness of less than 20 mm. The optically matched isolation interface blocks the diffusion of organic media in each layer and ensures the consistency of optical refractive index.

[0254] The high-energy absorbing base 206 absorbs and dissipates the remaining kinetic energy at the end of the projectile penetration, preventing the shock wave from generating reflected stress waves at the bottom of the transparent soil model box 201, and ensuring the one-dimensionality of the stress state inside the transparent soil sample 203 and the accuracy of stress wave propagation throughout the penetration process.

[0255] The transparent soil model target module integrates a vacuum negative pressure regulating component, including a negative pressure regulating integrated valve 209 and a vacuum negative pressure pump 210. The gas exchange in the transparent soil model box 201 can be controlled by the negative pressure regulating integrated valve 209 and the vacuum negative pressure pump 210 to realize the preparation of transparent soil sample 203.

[0256] The high-speed optical observation module is equipped with an orthogonal composite multi-view imaging system, including three orthogonally arranged high-speed cameras 301 and three coaxially arranged laser emitters 302. The system integrates time-division multiplexing illumination control logic to achieve dynamic capture of the optical flow field of the projectile penetration process from all directions and multiple perspectives, avoiding blind spots caused by projectile obstruction.

[0257] The spatiotemporal multidimensional synchronous triggering integrated module adopts a linkage control logic based on "command-physical" dual-reference synchronization, including a trigger controller 401, a laser velocity probe 402, a non-contact laser triggering barrier array 403, and a data acquisition and control center 404.

[0258] The laser velocity measuring probe 402 is installed at the exit end of the projectile-satellite integrated launcher 103. The initial velocity of the projectile is measured by calibrating the length of the projectile and measuring the duration of the change in the signal collected by the laser velocity measuring probe 402.

[0259] The plane defined by the non-contact laser-triggered barrier array 403 is flush with the upper surface of the impact-resistant dense buffer layer 204. When the projectile cuts in at high speed, a photoelectric blocking signal is generated, which serves as the physical contact zero reference. The timing of the high-energy pulse output command sent from the data acquisition and control center 404 to the high-energy pulse capacitor power supply group 104 is used as the logical starting reference of the test system. The data acquisition and control center 404 has a built-in sub-microsecond timing logic operation unit for real-time calculation. and The phase difference drift between the two is calculated, and dynamic phase compensation is applied to the exposure window of the high-speed camera 301 to achieve precise coupling between the optical observation timing and the penetration physical timing.

[0260] The present invention also discloses a test method based on the above-mentioned test system, comprising the following steps:

[0261] 1) Transparent soil solid particles (fused silica sand), refractive index matching liquid (a mixture of n-dodecane and white oil), and tracer speckle particles with refractive index matching characteristics are layered and filled into the transparent soil model box 201 according to a preset density gradient. At a constant test temperature, the difference in refractive index between the transparent soil solid particles and the refractive index matching liquid is strictly controlled within ±0.002 to ensure the complete optical transparency of the transparent soil sample 203. The negative pressure regulating integrated valve 209 is activated, and the vacuum negative pressure maintaining pump 210 performs multi-stage gradient degassing treatment inside the model box 201 until no microbubbles remain inside the fluid, ensuring a constant negative pressure inside the transparent soil model box 201. The uniformity of the refractive index distribution of the sample is then finally verified using the laser sheet optical plane 303.

[0262] 2) The axial attitude of the multi-stage electromagnetic coil accelerator 102 is adjusted in real time by driving the attitude adjustment device 105 of the high-rigidity gantry 101. The coaxiality of the launch axis and the geometric center axis of the transparent soil model box 201 is checked in a closed loop, and the actuator is locked after the alignment is completed to ensure that the trajectory deviation of the unconstrained inertial flight segment meets the correction accuracy requirements, providing a physical basis for the stability of the subsequent penetration trajectory.

[0263] 3) The system logic starting reference is preset using the data acquisition and control center 404. The integrated projectile-satellite launcher 103 is driven to perform a low-pressure, no-load pre-test, accurately acquiring the response time sequence of the laser velocity probe 402, and simultaneously capturing the penetration physical trigger zero reference through the non-contact laser trigger barrier array 403. By calculating and updating the phase difference drift between the two, a precise trigger mapping table suitable for high strain rate environments is established, eliminating the influence of system circuit delay on test accuracy.

[0264] 4) The laser emitter 302 is activated and enters the working state, triggering the high-energy pulse capacitor power supply group 104 to execute multi-stage stepped discharge logic. The projectile is driven to accelerate within the multi-stage electromagnetic coil accelerator 102. After the projectile leaves the exit and enters the unconstrained inertial flight phase, the sabot is automatically triggered to disintegrate and separate. At the same time, the data acquisition and control center 404 sends a linkage exposure command to the high-speed camera 301 based on the physical zero moment, ensuring that the optical recording system enters the full-field physical field capture state the instant the projectile contacts the target surface.

[0265] 5) Based on time-division multiplexing control logic, three high-speed cameras 301 are driven to perform high-speed sampling at a preset frame rate. Using an orthogonal composite multi-view imaging component, the speckle displacement field inside the transparent soil sample 203 excited by the projectile penetration is acquired in a multi-dimensional sequence, and the optical signals are synchronously transmitted to the data acquisition control center 404 for real-time data buffering and storage.

[0266] 6) The DIC algorithm is employed to perform rigorous coordinate system reprojection transformation on the image sequences from each viewpoint, achieving precise alignment and matching in the spatial domain. Simultaneously, a multi-scale adaptive optimization strategy based on optical flow field constraints is introduced, focusing on refining local sub-regions within the high-strain gradient region surrounding the projectile. Through this solution process, the evolution characteristics of the transient strain rate cloud map, displacement vector field, and dynamic stress wave propagation within the soil are ultimately inverted and constructed, enabling visualized and quantitative analysis of the entire penetration process.

[0267] To ensure that this experimental system can acquire high-resolution and high-fidelity full-field deformation images under high strain rate impact loading conditions, its core design follows the following physical principles:

[0268] 1. Wave impedance mismatch theory:

[0269] In penetration tests, the reflection and transmission of stress waves at material interfaces are crucial for image clarity. When a stress wave (compression wave) is incident perpendicularly from medium I (impact-resistant dense buffer layer) to medium II (strain energy core observation layer), reflection inevitably occurs at the interface due to the difference in acoustic impedance between the two media. In this test system, the solid aggregate particle size of the transparent soil sample 203 is typically in the millimeter range, while the overall size of the transparent soil model box 201 is typically in the tens of centimeters range. The observation area covers a large number of particle units. At this scale, treating the discrete particle group as a macroscopic continuous medium for elastic wave propagation analysis conforms to the basic assumptions of continuum mechanics. During the test, the pressure field generated by the projectile penetration exhibits obvious directivity, and in the central region of the model box, the wavefront displays an approximately planar propagation characteristic. In the near-field region near the penetration axis, a plane wave impedance model is used for analysis, which can accurately describe the spatiotemporal evolution of the stress wave, and the calculation error is within a controllable engineering allowable range. Acoustic impedance of different media Defined as:

[0270]

[0271] in Indicates the density of the medium. This indicates the propagation speed of an elastic wave in the medium.

[0272] When the compression wave generated by the projectile impacting the impact-resistant dense buffer layer 204 propagates to the strain energy core observation layer 205, the dielectric impedance on both sides of the interface is inconsistent, resulting in a redistribution of energy. The reflection coefficient and transmission coefficient at the interface of different media are defined as follows:

[0273]

[0274] in, The reflection coefficient of the interface represents the ratio of the amplitude of the reflected stress wave to the amplitude of the incident wave. If the reflected wave is in phase with the incident wave, then the reflected wave is in phase with the incident wave; if If the reflected wave is out of phase with the incident wave, then the reflected wave is out of phase with the incident wave. It represents the transmission coefficient, which reflects the ratio of the transmitted stress wave amplitude to the incident wave amplitude. The acoustic impedance of the incident medium (such as a shock-resistant, dense buffer layer) is represented. This represents the acoustic impedance of the transmission-side medium (such as the strain energy core observation layer).

[0275] If two materials with significantly different physical properties are used directly in the experimental system, that is and The differences are obvious. A higher value results in strong reflection at the interface. This patent constructs a transition region with a smaller impedance gradient by adjusting the volume fraction of the fused silica sand aggregate, thus achieving... ,Right now This means that almost all incident energy enters the observation area without loss, achieving "acoustic transparency".

[0276] The presence of reflected waves not only interferes with the accurate propagation of stress waves but also causes severe artifacts in the image during DIC processing due to background noise superposition. Through gradient design based on the above physical principles, the system effectively maintains the one-dimensionality of the internal stress state of the transparent soil sample 203, ensuring the purity of optical observation.

[0277] 2. Electromagnetic drive principle:

[0278] The electromagnetic catapult launch module of this invention is based on Maxwell's electromagnetic field theory and Lorentz force law, realizing the efficient conversion from pulsed electrical energy to projectile kinetic energy.

[0279] (1). The principle of electromagnetic induction and magnetic field coupling:

[0280] This system employs a multi-stage electromagnetic coil accelerator 102, and uses a high-energy pulse capacitor power supply group 104 to input a high-amplitude pulse current into the coil in a short time. According to Maxwell's equations and Faraday's law of electromagnetic induction, this transient current generates a strong magnetic field inside the coil that changes drastically with time. It satisfies:

[0281]

[0282] in, This represents the electric field strength.

[0283] The time-varying magnetic field induces eddy current density inside the conductive metal components of the projectile-sat integrated launcher 103. The interaction between the induced eddy currents and the external magnetic field generates an electromagnetic driving force, which drives the projectile to accelerate along the axis.

[0284] (2). Electromagnetic driving force model:

[0285] The driving force experienced by the projectile in the multi-stage electromagnetic coil accelerator 102 follows the Lorentz force law. Since the system involves dynamic changes in inductance with position, the driving force model is expressed as:

[0286]

[0287] in, This represents the axial electromagnetic driving force acting on the projectile. This represents the instantaneous pulse current in the coil circuit; This represents the equivalent inductance of the system, and the value is determined by the position of the projectile. The function;

[0288] The inductance gradient represents the ability of the magnetic circuit system to convert energy during the projectile's motion.

[0289] In a specific implementation, this experimental system can precisely adjust the current by controlling the discharge sequence of the high-energy pulse capacitor power supply group 104. The amplitude and waveform. Combined with... The spatial distribution design (through optimization of coil winding geometry) enables precise mechanical control of the entire projectile acceleration process, overcoming the problem of unstable force field caused by the reliance on high-pressure gas propulsion in traditional air guns.

[0290] This experimental system directly inputs the circuit parameters ( ) and mechanical motion parameters ( This correlation enables the data acquisition and control center 404 to reverse-calculate the required discharge command based on the target's initial velocity when generating global timing signals, ensuring the predictability of the projectile's state before and after entering the "unconstrained inertial flight phase".

[0291] During the experiment, the electromagnetic field oscillations and mechanical vibrations of the electromagnetic drive process exhibit high-frequency characteristics. If the projectile penetrates the coil in close proximity, the residual electromagnetic field will severely interfere with the displacement field measurement of the strain energy core observation layer 205. This system introduces an "unconstrained inertial flight segment," achieving physical isolation between the electromagnetic drive force field and the sample response process in terms of dynamics. This design ensures that the projectile is only subjected to inertial forces after leaving the coil, guaranteeing a stable dynamic vector at the moment the projectile penetrates the sample. This aligns with the ideal assumption of an inertial reference frame in classical mechanics, ensuring a high degree of unity between "acoustic transparency" and "optical visualization" during the penetration process.

Claims

1. A visualization test system for high-speed electromagnetic catapult penetration of transparent soil, characterized in that: It includes an electromagnetic catapult launch module, a transparent soil model target module, a high-speed optical observation module, a spatiotemporal multidimensional synchronous triggering integration module, and a data acquisition and control center (404). The electromagnetic catapult launch module includes a gantry (101), a multi-stage electromagnetic coil accelerator (102), and a high-energy pulse capacitor power supply group (104). The multi-stage electromagnetic coil accelerator (102) is suspended on the gantry (101). Each coil in the multi-stage electromagnetic coil accelerator (102) is connected to the high-energy pulse capacitor power supply group (104) to form an independent discharge circuit. The high-energy pulse capacitor power supply group (104) outputs pulse current to each coil according to the timing trigger command sent by the data acquisition control center (404). The pulse current enters each coil, exciting the coil to generate a pulse magnetic field. The pulse magnetic field interacts with the projectile (107) in the multi-stage electromagnetic coil accelerator (102) to form an axial electromagnetic thrust, which pushes the projectile (107) to move forward along the axial direction of the multi-stage electromagnetic coil accelerator (102). The transparent soil model target module includes a transparent soil model box (201) and a composite elastic self-closing sealing assembly (202); the transparent soil model box (201) is located directly below the multi-stage electromagnetic coil accelerator (102); the top of the transparent soil model box (201) is open, and a transparent soil sample (203) is placed inside the box, with the composite elastic self-closing sealing assembly (202) on the top of the transparent soil sample (203). The high-speed optical observation module includes a high-speed camera (301) and a laser emitter (302); the high-speed optical observation module is used to acquire the deformation image of the transparent soil sample (203) when the projectile (107) impacts the transparent soil sample (203); The spatiotemporal multidimensional synchronous triggering integrated module includes a trigger controller (401), a laser velocity probe (402), and a non-contact laser triggering barrier array (403); the laser velocity probe (402) is located at the exit end of the multi-stage electromagnetic coil accelerator (102); the non-contact laser triggering barrier array (403) is positioned flush with the top surface of the transparent soil sample (203); the trigger controller (401) is connected to the high-energy pulse capacitor power supply group (104), the high-speed camera (301), the laser velocity probe (402), and the non-contact laser triggering barrier array (403) respectively, and is used to calibrate and set the test time. During the test, the initial velocity of the projectile (107) is calculated based on the time when the projectile head and tail pass through the laser velocity probe (402) and the length of the projectile (107). The phase difference drift is calculated based on the timing of the timing trigger command sent by the data acquisition control center (404) and the timing of the photoelectric blocking signal generated by the non-contact laser trigger barrier array (403), which is used to perform dynamic phase compensation on the exposure window of the high-speed camera (301) and the laser emitter (302).

2. The electromagnetic catapult high-speed penetration transparent soil visualization test system according to claim 1, characterized in that: The multi-stage electromagnetic coil accelerator (102) includes coils, a launcher (103), a sabot (106), and a projectile (107). The launcher (103) is a hollow, closed-end, and open-end rotating structure. Several coils are sleeved on the outside of the launcher (103) along the axial direction of the launcher (103). The launcher (103) is coaxially provided with a projectile support (106) and a projectile (107). The projectile support (106) is attracted to the closed side of the launcher (103) by a magnet and is used to fix the projectile (107) when the high-energy pulse capacitor power supply group (104) is not activated.

3. The electromagnetic catapult high-speed penetration transparent soil visualization test system according to claim 2, characterized in that: The outer periphery of the sabot (106) is coated with lubricant.

4. The electromagnetic catapult high-speed penetration transparent soil visualization test system according to claim 1, characterized in that: The multi-stage electromagnetic coil accelerator (102) is suspended on the crossbeam of the gantry (101) by a posture adjustment device (105); The pose adjustment device (105) makes the axis of the multi-stage electromagnetic coil accelerator (102) and the axis of the transparent soil model box (201) lie on the same straight line.

5. The electromagnetic catapult high-speed penetration transparent soil visualization test system according to claim 1, characterized in that: The transparent soil sample (203) consists of, from top to bottom, an impact-resistant compaction buffer layer (204), a strain energy core observation layer (205), and a high-energy absorption base (206). Both the impact-resistant dense buffer layer (204) and the strain energy core observation layer (205) include solid particles and porous media; The volume of solid particles in the impact-resistant dense buffer layer (204) accounts for 42% to 45% of the total volume of the impact-resistant dense buffer layer (204); The volume of solid particles in the strain energy core observation layer (205) accounts for 38% to 42% of the total volume of the strain energy core observation layer (205); Tracer particles are uniformly distributed in the strain energy core observation layer (205); An optical matching isolation interface (207) is provided between the impact-resistant dense buffer layer (204) and the strain energy core observation layer (205); the optical matching isolation interface (207) has a thickness of less than 20 mm. Flexible fluoroplastic separator membrane; The high-energy-absorbing base (206) comprises a porous polyurethane elastomer and a silicone rubber particle composite material, wherein the mass fraction of the porous polyurethane elastomer is 75% to 85% and the mass fraction of the silicone rubber particle material is 15% to 25%.

6. The electromagnetic catapult high-speed penetration transparent soil visualization test system according to claim 1, characterized in that: The composite elastic self-closing sealing assembly (202) has a double-layer structure, including an outer polyurethane sealing film and an inner self-healing gel layer; The self-healing gel layer is a self-healing silicone coating applied to the side of the polyurethane sealing film near the transparent soil sample (203).

7. The electromagnetic catapult high-speed penetration transparent soil visualization test system according to claim 1, characterized in that: The transparent soil model target module also includes a vibration isolation test bench (208), a negative pressure regulating integrated valve (209), and a vacuum negative pressure pump (210). The transparent soil model box (201) is set on the vibration isolation test bench (208), and the transparent soil model box (201) is equipped with a negative pressure regulating integrated valve (209), which is connected to a vacuum negative pressure pump (210).

8. The electromagnetic catapult high-speed penetration transparent soil visualization test system according to claim 1, characterized in that: The high-speed optical observation module includes three high-speed cameras (301) and three laser emitters (302). The transparent soil model box (201) is equipped with a high-speed camera (301) and a laser emitter (302) on its top and two adjacent side walls.

9. The electromagnetic catapult high-speed penetration transparent soil visualization test system according to claim 1, characterized in that: When the projectile (107) cuts into the transparent soil sample (203) and passes through the non-contact laser-triggered barrier array (403), the optical signal is blocked and the output electrical signal jumps. During the experiment, the starting reference time was the moment when the data acquisition and control center (404) sent the timing trigger command to the high-energy pulse capacitor power supply group (104). ; The moment when the non-contact laser-triggered barrier array (403) generates the transition signal is the zero reference for penetrating the physical trigger. ;calculate and Phase difference drift between Based on the phase difference drift, dynamic phase compensation is performed on the exposure windows of the high-speed camera (301) and the laser emitter (302).

10. A method of using an electromagnetic catapult high-speed penetration transparent soil visualization test system according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1, Connecting the test system, including the electromagnetic catapult launch module, the transparent soil model target module, the high-speed optical observation module, the spatiotemporal multidimensional synchronous triggering integration module, and the data acquisition and control center (404). S2. Prepare transparent soil samples (203) in a transparent soil model box (201). Start the negative pressure regulating integrated valve (209) and degas the inside of the transparent soil model box (201) through the vacuum negative pressure maintaining pump (209) until there are no air bubbles inside the refractive index matching liquid. S3. Drive the posture adjustment device (105) to make the axis of the multi-stage electromagnetic coil accelerator (102) and the axis of the transparent soil model box (201) on the same straight line. S4. Set timing trigger instructions in the data acquisition control center (404) to confirm the discharge time of each stage of the coil in the multi-stage electromagnetic coil accelerator (102); The starting reference time is the moment when the data acquisition control center (404) sends the timing trigger command to the high-energy pulse capacitor power supply group (104). ; S5. Turn on the laser emitter (302); based on the timing trigger command, trigger the high-energy pulse capacitor power supply group (104) to output pulse current, and drive the projectile (107) to accelerate in multiple stages; when the projectile (107) enters the non-contact laser trigger barrier array (403), the high-speed camera (301) is turned on through the trigger controller (401). During the experiment, the timing of the timing trigger command issued by the data acquisition control center (404) was recorded. The non-contact laser-triggered barrier array (403) generates a transition signal at the time when... ; S6, Time-based , Calculate the time drift And through time drift The acquisition window of the high-speed camera (301) and the pulse exposure sequence of the laser emitter (302) are corrected; S7. Receive and store the speckle image sequence of the entire penetration process captured by the high-speed camera (301) through the data acquisition and control center (404); S8. Based on the digital image correlation algorithm, the speckle image sequence is processed to obtain a two-dimensional displacement vector field; then, through the reprojection model, the two-dimensional displacement vector field is transformed into a three-dimensional physical coordinate system to reconstruct a three-dimensional visualization image. S9. Based on the multi-scale adaptive optimization strategy constrained by optical flow field, the speckle image sequence is processed to obtain the displacement vector field. Then, by performing gradient analysis on the displacement vector field, a full spectrum of multi-physics field evolution, including the full-field transient strain rate cloud map and the stress wave propagation, is generated.

Images