A multi-field coupling analysis electromagnetic rail damage detection method and system

Abstract

The application discloses a kind of electromagnetic track damage detection method and system of multi-field coupling analysis, it is related to electromagnetic track launcher technical field, including: obtaining simulated armature loop pulse current, armature mechanical parameter and armature kinematics parameter, import electromagnetic heat multi-physics field coupling model, obtain field-circuit coupling model;Obtain the distribution of current density and temperature along the boundary of armature slot inside boundary and pivot rail contact interface boundary in the simulation process under multi-physics field coupling;According to the change of current density and temperature under different armature placement initial position, determine the optimal initial position of armature placement, and according to the change of current density and temperature under the different electromagnetic transmitter track material set, determine optimal track material;Build electromagnetic track launch system simulation experiment platform, test the surface damage of track at different positions under different pulse current peak and launch times, clarify the characteristics of track surface cumulative wear and ablation damage under different working conditions.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic orbital launch device technology, and in particular to an electromagnetic orbital damage detection method and system based on multi-field coupling analysis. Background Technology

[0002] Simulation models of electromagnetic orbital launch devices are fundamental to the study of electromagnetic orbital launch principles. They can not only provide guidance and optimization for the design of electromagnetic launch experimental platforms, reduce experimental costs and verify launch effects, but also quantify and analyze extreme operating conditions, thereby discovering parameters that cannot be observed in experiments, such as the spatiotemporal distribution characteristics of multi-physics coupling between the armature and the orbit during launch.

[0003] Current research on electromagnetic rail launch device modeling often focuses solely on the topological calculations of equivalent circuits or the coupling effects of static multiphysics fields, without establishing field-circuit coupling mechanisms and co-simulation strategies. This would prevent the introduction of equivalent electrical parameter conditions from the circuit model into multi-field coupled models, thus enhancing the model's realism and the accuracy of simulation results. Furthermore, most existing finite element models for electromagnetic rail launch are static, steady-state models, making it difficult to simulate the dynamic motion of the armature and the time-domain variations of various parameters during launch. The impact of electromagnetic rail launch conditions on the parameters of the field-circuit coupled model is also not thoroughly explored. The initial armature placement and track material—two crucial launch conditions—are rarely studied, failing to provide simulation-level guidance for electromagnetic rail launch system simulation platforms.

[0004] The pivot rail is subjected to extreme impacts from electromagnetic and thermodynamic multi-field coupling, causing current-carrying frictional wear and various ablation damages on its surface. This is the fundamental reason why the widespread application of electromagnetic railguns is limited. Simulation and theoretical analysis require experimental data as a foundation and verification. Establishing a simulation experimental platform for the electromagnetic launch system and developing testing methods for rail surface damage will facilitate research on the wear and ablation characteristics of the rail surface under different operating conditions, providing a platform support for studying the generation mechanism and evolution law of pivot-rail transition and arc ablation.

[0005] Existing electromagnetic rail launch device simulation experimental platforms mostly focus on measuring macroscopic electrical quantities such as output current and contact resistance. There are few means to detect the microscopic morphology of metal material surfaces, making it impossible to effectively observe the surface geometric characteristics and damage morphology of rail materials. Furthermore, the measurement of wear and ablation of rail surfaces under different experimental conditions has not been carried out in depth. Summary of the Invention

[0006] To address the aforementioned issues, this invention proposes a multi-field coupling analysis method and system for electromagnetic track damage detection. It performs field-path coupling dynamic modeling and co-simulation analysis on the electromagnetic track launching device, investigates the influence of the initial armature placement and launch conditions of the track material on the field-path coupling model, observes the microscopic damage state of the track surface and establishes its relationship with damage types, and clarifies the characteristics of cumulative wear and ablation damage on the track surface under different operating conditions.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for detecting electromagnetic track damage using multi-field coupling analysis, comprising:

[0009] Construct an equivalent circuit model and an electromagnetic-thermal multiphysics coupling model for an electromagnetic orbital launch device;

[0010] The armature circuit pulse current, armature mechanical parameters, and armature kinematic parameters obtained after launching simulation of the equivalent circuit model are acquired and imported into the electromagnetic-thermal multiphysics coupling model to obtain the field-circuit coupling model of the electromagnetic track launch device.

[0011] Based on the field-path coupling model, the distribution patterns of current density and temperature along the boundary of the armature contact interface and the inner boundary of the armature groove are obtained during the launch simulation under electromagnetic and thermal multi-physics field coupling, so as to determine the concentrated distribution location when the current density and temperature are the highest.

[0012] Based on the changes in armature circuit pulse current, armature mechanical parameters, armature kinematic parameters, and current density and temperature at the concentrated distribution location under different initial armature placement positions, the optimal initial position for armature placement is determined. Furthermore, based on the changes in current density and temperature at the concentrated distribution location under different electromagnetic transmitter track materials at the optimal initial position, the optimal track material is determined.

[0013] Based on the optimal initial position of the armature and the optimal track material for the electromagnetic transmitter, a simulation experimental platform for the electromagnetic track launch system was built to test the surface damage at different positions of the track under different pulse current peak values ​​and launch counts.

[0014] Secondly, the present invention provides an electromagnetic track damage detection system based on multi-field coupling analysis, comprising:

[0015] The model building module is configured to build an equivalent circuit model of the electromagnetic orbital launch device and an electromagnetic-thermal multiphysics coupling model.

[0016] The coupling module is configured to acquire the armature loop pulse current, armature mechanical parameters and armature kinematic parameters obtained after launching simulation of the equivalent circuit model, and import them into the electromagnetic-thermal multiphysics coupling model to obtain the field-circuit coupling model of the electromagnetic track launch device.

[0017] The analysis module is configured to obtain the distribution patterns of current density and temperature along the boundary of the armature contact interface and the inner boundary of the armature groove during the launch simulation under electromagnetic and thermal multi-physics field coupling, thereby determining the concentrated distribution location when the current density and temperature are highest.

[0018] The optimization module is configured to determine the optimal initial position for armature placement based on the changes in armature rail circuit pulse current, armature mechanical parameters, armature kinematic parameters, and current density and temperature at the concentrated distribution location under different initial armature placement positions. Furthermore, under the optimal initial position, the optimal rail material is determined based on the changes in current density and temperature at the concentrated distribution location under different electromagnetic transmitter rail materials.

[0019] The detection module is configured to build a simulation experimental platform for the electromagnetic track launch system based on the optimal initial position of the armature and the optimal track material of the electromagnetic transmitter, so as to test the surface damage at different positions of the track under different pulse current peaks and launches.

[0020] Thirdly, the present invention provides an electronic device including a memory and a processor, and computer instructions stored in the memory and running on the processor, wherein the computer instructions, when executed by the processor, perform the method described in the first aspect.

[0021] Fourthly, the present invention provides a computer-readable storage medium for storing computer instructions, which, when executed by a processor, perform the method described in the first aspect.

[0022] Fifthly, the present invention provides a computer program product, including a computer program that, when executed by a processor, implements the method described in the first aspect.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] Current research on modeling electromagnetic rail launch devices often focuses only on the topological operations of the equivalent circuit or the coupling effects of static multiphysics fields, without establishing a common coupling mechanism and collaborative simulation strategy between the two. Furthermore, the impact of launch conditions on various parameters of the model is not thoroughly investigated. Therefore, this invention, based on the equivalence equations of the pulse power supply and the armature-rail circuit, first establishes an equivalent circuit model of the electromagnetic rail launch device. The simulated electrical, mechanical, and kinematic data are then imported into the multiphysics coupling model, enabling joint programming of the field-circuit coupling model of the electromagnetic rail launch device and simulation equivalence of the experimental platform. The spatiotemporal dynamic distribution of current density and temperature under multiphysics coupling is analyzed. Furthermore, the influence of the initial armature placement position and track material on the electrical, mechanical, and kinematic parameters of the field-circuit coupling model, as well as the multiphysics coupling distribution characteristics, is explored, providing numerical simulation support for the optimized design of the electromagnetic rail launch system simulation experimental platform.

[0025] Because existing electromagnetic rail launch experimental platforms and their measurement systems focus more on extracting and analyzing electrical parameters such as pulse current, charging voltage, and contact resistance, or kinematic parameters such as armature exit velocity and effective range, they do not perform detailed measurements of the microscopic morphology and damage level of the rail material surface under different launch conditions. Therefore, this invention, based on the equivalence conditions and simulation results of the field-circuit coupling model of the electromagnetic rail launch device, constructs a simulation experimental platform for the electromagnetic rail launch system. The initial position of the armature is determined to be 150mm deep into the rail, and the rail material of the electromagnetic launcher is determined to be a copper-steel composite material. Scanning electron microscopy and laser scanning confocal microscopy together constitute a microscopic measurement system for rail surface damage. The microscopic morphology, aluminum element distribution and content, and surface roughness at different positions of the rail are compared and analyzed under two experimental conditions: peak pulse current and number of experimental launches. The wear and ablation damage characteristics of the high-current high-speed sliding rail electrical contact surface are obtained. Parameters such as the microscopic morphology and elemental content of track surface damage detected at the microscopic level help to achieve numerical characterization of damage morphology and clarify the variation law of key damage characteristic parameters under different launch conditions. By making full use of the characteristics of severe wear and ablation problems and diverse damage morphology of electromagnetic track, we can observe and record the microscopic damage state of track surface from multiple angles and methods and establish its relationship with damage type, so as to clarify the characteristics of cumulative wear and ablation damage of track surface under different conditions. Attached Figure Description

[0026] Figure 1 This is a flowchart of the electromagnetic track damage detection method based on multi-field coupling analysis provided in Embodiment 1 of the present invention;

[0027] Figure 2 The equivalent circuit diagram of the electromagnetic orbital launching device provided in Embodiment 1 of the present invention;

[0028] Figure 3 The graph shows the variation of pulse current amplitude, electromagnetic driving force and dry sliding friction force on the armature, armature speed and displacement with launch time, as provided in Embodiment 1 of the present invention.

[0029] Figure 4 The armature current density distribution diagram and the track current density distribution diagram are provided in Embodiment 1 of the present invention;

[0030] Figure 5 The armature temperature distribution diagram and the track temperature distribution diagram provided in Embodiment 1 of the present invention;

[0031] Figure 6 This is a diagram showing the boundary of the pivot-rail contact interface and the temperature spatial distribution along the boundary of the pivot-rail contact interface provided in Embodiment 1 of the present invention.

[0032] Figure 7 This is a temperature spatial distribution diagram along the inner boundary of the armature groove and along the inner boundary of the armature groove provided in Embodiment 1 of the present invention;

[0033] Figure 8 This is a graph showing the variation trend of pulse current and electromagnetic driving force under different initial armature placement positions provided in Embodiment 1 of the present invention;

[0034] Figure 9 This is a graph showing the variation trend of dry sliding friction and resultant force under different initial armature placement positions provided in Embodiment 1 of the present invention;

[0035] Figure 10 This is a graph showing the variation trend of armature acceleration and armature velocity under different initial armature placement positions provided in Embodiment 1 of the present invention.

[0036] Figure 11 This is a graph showing the trend of armature displacement under different initial armature placement positions provided in Embodiment 1 of the present invention.

[0037] Figure 12 This is a graph showing the variation trend of average current density and average temperature at the center of the armature recess under different initial armature placement positions provided in Embodiment 1 of the present invention.

[0038] Figure 13 This is a graph showing the variation trend of average current density and average temperature at the armature rail contact interface under different initial armature placement positions provided in Embodiment 1 of the present invention.

[0039] Figure 14 The diagram shows the highest temperature and the time of occurrence at the center of the armature groove and the contact interface with the armature rail under different initial armature placement positions provided in Embodiment 1 of the present invention.

[0040] Figure 15This is a graph showing the variation trend of average current density and average temperature at the center of the armature groove under different track materials provided in Embodiment 1 of the present invention.

[0041] Figure 16 This is a graph showing the variation trend of average current density and average temperature at the pivot rail contact interface under different rail materials, as provided in Embodiment 1 of the present invention.

[0042] Figure 17 This is a diagram showing the highest temperature distribution at the center of the armature groove and the armature-rail contact interface under different rail materials provided in Embodiment 1 of the present invention.

[0043] Figure 18 This is a schematic diagram of the electromagnetic orbital launch system simulation experimental platform provided in Embodiment 1 of the present invention;

[0044] Figure 19 A comparison diagram of the root mean square heights of tracks 1 and 2 provided in Embodiment 1 of the present invention;

[0045] Figure 20 A comparison diagram of the root mean square height of the surfaces of track 1 and track 3 provided in Embodiment 1 of the present invention. Detailed Implementation

[0046] Example 1

[0047] This embodiment provides a multi-field coupling analysis method for electromagnetic track damage testing, such as... Figure 1 As shown, it includes:

[0048] Construct an equivalent circuit model and an electromagnetic-thermal multiphysics coupling model for an electromagnetic orbital launch device;

[0049] The armature circuit pulse current, armature mechanical parameters, and armature kinematic parameters obtained after launching simulation of the equivalent circuit model are acquired and imported into the electromagnetic-thermal multiphysics coupling model to obtain the field-circuit coupling model of the electromagnetic track launch device.

[0050] Based on the field-path coupling model, the distribution patterns of current density and temperature along the boundary of the armature contact interface and the inner boundary of the armature groove are obtained during the launch simulation under electromagnetic and thermal multi-physics field coupling, so as to determine the concentrated distribution location when the current density and temperature are the highest.

[0051] Based on the changes in armature circuit pulse current, armature mechanical parameters, armature kinematic parameters, and current density and temperature at the concentrated distribution location under different initial armature placement positions, the optimal initial position for armature placement is determined. Furthermore, based on the changes in current density and temperature at the concentrated distribution location under different electromagnetic transmitter track materials at the optimal initial position, the optimal track material is determined.

[0052] Based on the optimal initial position of the armature and the optimal track material for the electromagnetic transmitter, a simulation experimental platform for the electromagnetic track launch system was built to test the surface damage at different positions of the track under different pulse current peak values ​​and launch counts.

[0053] The following section first describes the specific process of constructing the equivalent circuit model of the electromagnetic orbital launch device.

[0054] Under ideal conditions of good contact between the rail and the armature, neglecting resistive losses in both the rail and the armature, the electromagnetic driving force of the electromagnetic rail launcher can be obtained based on the law of conservation of energy and the power balance condition. With inductance gradient Pulse current i Relationship between them: ; m For armature mass, For armature acceleration, The net force on the armature, The dry sliding friction force on the contact surface on one side of the armature, and the electromagnetic driving force. This is the Ampere force experienced by the armature in the electromagnetic field. Therefore, the armature's acceleration... Armature speed and armature displacement for:

[0055] (1);

[0056] (2);

[0057] (3).

[0058] Among them, the dry sliding friction is Contact pressure N for F e The sum of the vertical component and the preload pressure. Therefore, the dry sliding friction force on the armature is: .

[0059] Under the velocity skin effect, the equivalent contact resistance of the pivot-rail contact interface R v Contact resistance due to armature velocity skin effect R vA Contact resistance and the velocity of the track, skin effect R vR constitute:

[0060] (4);

[0061] (5);

[0062] (6);

[0063] In the formula, k v It is the proportional constant of the contact resistance due to the velocity skin effect; ρ f It is the resistivity of the pivot-rail contact interface, typically on the order of 10. -11 Up to 10 -12 Between Ω·m; A c It is the contact area between the armature and the track; v A It is the armature speed.

[0064] Based on the above analysis, an equivalent circuit model of the electromagnetic orbital launch device is constructed, such as... Figure 2 As shown, it includes a pulse power supply module and a pivot circuit module. In the pulse power supply module, C 1. C 2 represents the capacitance values ​​of two pulse capacitors with identical specifications and models. U C1 , U C2 For their charging voltage; L C1 , L C2 The stray inductance of the two pulse capacitors; R C1 , R C2 The stray resistance of the two pulse capacitors; Q 1 is a thyristor switching assembly with a trigger circuit; D 1 is a protective diode. In the pivot circuit module, R L , L L These are tuning resistors and tuning inductors, whose function is to adjust the current wave generated by the pulse capacitor. R v It is the contact resistance equivalent to the velocity skin effect; R A and L A These are the equivalent resistance and equivalent inductance of the aluminum alloy armature, respectively. R R , L R These are the equivalent resistance and equivalent inductance of the copper rails. During launch, as the armature displacement increases, the rail resistance and inductance connected in series with the armature-rail circuit also continuously increase. R R and LR for:

[0065] (7);

[0066] (8);

[0067] In the formula, R 0 and L 0 represents the initial resistance and inductance of the rail in the pivot-rail circuit, determined by the initial position of the armature in the rail at a distance from the breech before firing. x 0 decision; For resistance gradient, For inductance gradient, x This represents the armature displacement during the launch process.

[0068] To more clearly clarify the relationship between pulse current amplitude, armature mechanical parameters, and kinematic parameters during the dynamic process of electromagnetic orbit launch, six time points—0.5 ms, 1.13 ms, 2 ms, 4 ms, 6 ms, and 8 ms—were selected to investigate the variations in pulse current amplitude, electromagnetic driving force and dry sliding friction on the armature, and armature velocity and displacement with launch time. Figure 3 As shown, the pulse current, the electromagnetic driving force on the armature, and the dry sliding friction force all exhibit the same trend with the launch time: they all rapidly increase from 0 to their peak value and then continuously decrease. The three parameters all reach their peak values ​​simultaneously at 1.13 ms. However, the armature velocity and armature displacement show a continuous increasing trend during armature motion. Since the armature acceleration value, like the pulse current and mechanical parameters, initially increases and then decreases, the armature velocity initially rises rapidly with a large slope, then gradually flattens out as the armature approaches the barrel. The armature displacement is the integral of the armature velocity, so its growth slope continuously increases as the armature velocity increases.

[0069] The following describes the dynamic modeling and co-simulation analysis process of the field-path coupling model of the electromagnetic orbital launch device.

[0070] Based on the equivalent circuit model of the electromagnetic rail launch device, an electromagnetic-thermal multiphysics coupling model is established, with the armature material set to aluminum alloy 6061. The pulse current, armature mechanical parameters, and armature kinematic parameters obtained from the equivalent circuit model simulation are imported into the multiphysics coupling model for joint programming of the electromagnetic rail launch device field-circuit coupling model. Specifically, pulse current data is introduced as the current terminal in the current field boundary conditions of the field model. The electromagnetic driving force and armature velocity are used to indirectly calculate the thermal power at the armature-rail contact interface. The armature displacement is simulated using the model's dynamic mesh function to depict the entire dynamic launch process of the armature in the track. Finally, a dynamic coupling mechanism and collaborative simulation strategy between the field and circuit models are constructed, effectively improving the simulation accuracy and precision of the multiphysics coupling model. To improve the reliability of the simulation results, heat generation from contact resistance and dry friction between the armature and rail in the thermal field are considered. For the contact resistance between the armature and rail, its contact resistivity is: In the formula, ρ R The orbital resistivity; ρ A Armature resistivity; l c The thickness of the contact layer; H A Armature hardness; A c The contact area between the armature and the track; F c The contact pressure between the pivot and the rail. R c Let c be the contact resistance, and its value be 10.4 × 10⁻⁶. -4 The constant of . Among them, contact resistance. R c The value is related to the number of micro-contact points in the pivot rail contact interface: In the formula, n This represents the number of micro-contact points; ξ This is a correction factor for elastic deformation. The multiphysics coupling model of the electromagnetic orbital launch device only considers the ideal situation where no transition occurs during launch, i.e., the contact resistance at the pivot-rail interface does not increase sharply due to loss of contact between the pivot and rail caused by the transition. Therefore, the contact resistance value is only on the order of nanoohms, set at 4.1405 × 10⁻⁶. -10 Ω·m 2 .

[0071] For dry frictional heat generation, the instantaneous thermal power at each moment during the launch process is: The heat generated by contact resistance and dry friction at the armature-rail interface can be used to determine the temperature rise on the armature and rail respectively, according to the heat transfer equation expressed by the following formula:

[0072] (9);

[0073] (10);

[0074] In the formula, σ A , σ R These represent the densities of the armature and the track, respectively. C A , C R The constant-pressure heat capacity of the armature and track; k A , k R Thermal conductivity of the armature and track; T A , T R These are the temperatures of the armature and the track, respectively. Q A The contact resistance Joule heat and frictional heat transferred to the armature from the armature at the armature rail contact interface; Q R This refers to the Joule heat and frictional heat transmitted from the pivot-rail contact interface to the track due to contact resistance.

[0075] A multi-field coupled model of the electromagnetic orbital launch device was meshed. A simulation step size of 0.5 ms and a simulation duration of 9 ms were selected to obtain simulation results of the spatial distribution of current density and temperature in the armature and track at a launch time of 2 ms. Figure 4 As shown, Figure 4 Figures (a) and (b) show the current density distribution of the armature and track, respectively. In the armature, due to the skin effect, the pulse current flowing through the armature tends to concentrate on the surface with the smallest radius of curvature, resulting in the area with the highest current density being concentrated at the center of the armature groove, reaching a value of 9.75 × 10⁻⁶. 8 A / m 2 In the track, due to the velocity skin effect, the maximum current density is located at the point where the armature tail fin contacts the track, and its value is 4.94 × 10⁻⁶. 8 A / m 2 The current density must be less than the maximum current density at the center of the armature groove, and the current density at the armature-rail contact interface will continuously decrease along the emission direction.

[0076] like Figure 5 As shown, Figure 5Figures (a) and (b) show the temperature distribution of the armature and track, respectively. The highest temperature in the armature is concentrated at the center of the armature groove, reaching 66.5℃, while the next highest temperature area is concentrated on the contact side between the armature and the track. In the track, the highest temperature is located at both ends of the armature-track contact interface, with the highest temperature at the beginning (34.7℃). The next highest temperature area is distributed in the track section through which pulsed current flows. This shows that in the entire electromagnetic track launch device, due to the difference in thermal conductivity and constant-pressure heat capacity of the materials, the highest temperature at the center of the aluminum alloy armature groove is higher than the highest temperature at the beginning of the copper track contact interface. Furthermore, due to the Joule heating generated when the pulsed current flows through the track and armature, the areas of concentrated current density in the armature and track are also high-temperature areas, and these high-temperature areas are more prone to ablation damage. Therefore, this study investigates the spatial distribution of temperature along the boundary of the armature-track contact interface and the inner boundary of the armature groove at the 2ms launch time.

[0077] like Figure 6 As shown, Figure 6 Figures (a) and (b) show the temperature spatial distribution along the boundary of the pivot-rail contact interface, respectively. It can be seen that along the upper boundary of the pivot-rail contact interface, from the end of the armature tail fin to the armature head, the temperature first decreases, then increases, and then decreases slightly again, with the temperature at the end of the armature tail fin reaching 27.245℃. From the intersection of the straight boundary and the arc boundary of the armature head, up to the midpoint of the foreground of the contact interface, the temperature distribution shows a rapid increase followed by a slight decrease, reaching its highest peak of 34.663℃ near the midpoint of the foreground of the contact interface. Overall, the temperature distribution pattern at the pivot-rail contact interface is "higher at both ends and lower in the middle," with the highest temperature region concentrated at the foreground of the contact interface and the second highest temperature region concentrated at the end.

[0078] like Figure 7 As shown, Figure 7Figures (a) and (b) show the temperature spatial distribution along the inner boundary of the armature groove, respectively. It can be seen that the temperature spatial distribution along the inner boundary of the armature groove is symmetrical about the center point of the groove (28.334 mm from the end of the armature tail fin). Along one side of the armature tail fin end boundary, the temperature shows a continuous decreasing trend, reaching its lowest value at the inflection point of the armature tail fin end. From the inflection point of the armature tail fin end along the inner boundary of the armature groove to the center point of the groove, the temperature increases at an increasingly faster rate, eventually reaching a maximum peak of 66.547℃ at the center point of the armature groove. With the center point of the armature groove as the symmetrical point, the temperature distribution from the center point to the other side follows the opposite pattern. Therefore, the center of the armature groove and its surrounding area are the regions with the highest temperature concentration, and the highest temperature at the center point of the armature groove is approximately twice the highest temperature at the front end of the armature-rail contact interface. Therefore, for the armature, in addition to paying attention to the current-carrying friction wear caused by friction between its contact side and the rail, it is also necessary to pay attention to the ablation damage caused by high temperature at the armature groove.

[0079] The influence of the initial position of the armature and the track material on the field-path coupling model is explained below.

[0080] 1. Place the armature in its initial position.

[0081] According to equations (7) and (8), the initial position of the armature is determined. x 0 will directly change the initial resistance of the track in the pivot circuit. R 0 and initial inductance L 0, thus affecting the launch performance of the electromagnetic orbital launcher. Taking... x 0 represents 50mm, 100mm, 150mm, 200mm, and 250mm, and the calculations differ accordingly. x The initial resistance and inductance of the copper rails at 0 are substituted into the model for simulation analysis under different conditions. x The influence of 0 on the pulse current waveform flowing through the armature rail circuit and the mechanical and kinematic parameters of the armature during transmission, such as Figures 8-11 As shown; where, Figure 8 (a)-(b) in the text represent different x Graph showing the variation trend of pulse current and electromagnetic driving force at 0; Figure 9 (a)-(b) in the text represent different x Graph showing the changing trends of dry sliding friction and resultant force at 0°C; Figure 10 (a)-(b) in the text represent different x Trend graph of armature acceleration and armature velocity at 0°; Figure 11 For different x The trend of armature displacement at 0°C.

[0082] Depend on Figure 8 As shown in (a), as the initial armature position extends deeper into the track, the initial impedance of the armature-rail circuit increases, the peak value of the pulse current in the circuit decreases continuously, and the peak time lags further. However, the rate of decay of the pulse current from its peak value is slower. This is because, in the RC equivalent circuit of the pulse capacitor, the increase in the initial impedance of the circuit leads to a larger time constant, which in turn slows down the charging and discharging rate of the circuit. For example, when the initial armature position is only 50mm, the peak value of the pulse current is as high as 96.74kA, and the peak time is about 0.25ms; when the initial armature position increases to 250mm, the peak value of the pulse current decreases to 54.77kA, and the peak time is delayed to after 1.4ms; during the pulse current decay phase from 4ms to 12ms, the amplitude of the pulse current increases continuously with the increase in the initial armature position. Figure 8 (a)-(b) and Figure 9 In (a), under the condition that the preload and the coefficient of dry sliding friction between the armature and the rail remain constant, the electromagnetic driving force on the armature is... F e 、 Dry sliding friction F f The time-varying trend is consistent with that of electromagnetic force and pulse current. For example... Figure 9 (b) in Figure 11 The resultant force, armature acceleration, armature velocity, and armature displacement all decrease with increasing initial armature placement position. This indicates that the increased initial impedance of the armature-rail circuit due to the increased armature placement depth leads to a decrease in the amplitude of the circuit pulse current waveform. The changing trend of the pulse current ultimately determines the associated armature mechanical parameters, such as the electromagnetic driving force, dry sliding friction, and resultant force, as well as the changing trends of armature kinematic parameters, such as armature acceleration, velocity, and displacement. Specifically, during launch, the maximum armature velocity continuously decreases from 135.38 m / s at the initial placement position of 50 mm to... x 121.98 m / s when 0 = 250 mm; when x When 0=50mm, the maximum armature velocity is not the velocity at the moment of armature exiting the barrel, but occurs at 6.37ms. This is because the initial position of the armature is too small, causing the pulse current amplitude to decrease rapidly in the later stages of the firing time. As a result, the electromagnetic driving force on the armature is less than the dry sliding friction force, thus causing the armature acceleration to decrease. a A When the value becomes negative, the armature begins to decelerate in the later stages of the motion. v A It will decrease slightly. Further, select the center of the armature recess and the contact interface with the rail to compare different... xThe time-domain variation of the average current density and temperature at these two locations under 0°C was investigated. x The mechanism by which 0 affects the two highest temperatures and their occurrence time.

[0083] like Figure 12 As shown, Figure 12 Figures (a) and (b) show the trends of average current density and temperature at the center of the armature recess under different initial armature placement positions, respectively. x At 0°C, the average current density at the center of the armature recess exhibits the same trend as the pulse current with time, showing a pattern of rapid increase followed by slow decay. However, as the initial position of the armature increases, the time-domain waveform of the average current density becomes smoother, with both the rise and fall edges decreasing in steepness, and the rates of increase and decay of the average current density also slowing down. This leads to a situation where, during the rising phase of the average current density over time... x An increase of 0 causes a decrease in the average current density; while in its decay phase, x An increase of 0 leads to an increase in the average current density. The average temperature at the center of the armature recess also shows a time-domain variation pattern of first increasing and then decreasing, while increasing the initial position of the armature causes the average temperature at the center of the armature recess to continuously decrease at various times.

[0084] like Figure 13 As shown, Figure 13 Figures (a) and (b) show the trends of average current density and average temperature at the armature-rail contact interface under different initial armature placement positions. It can be seen that the time-varying trend of the average current density at the armature-rail contact interface is the same as that at the center of the armature recess, and the influence mechanism of the initial armature placement position on the average current density in both locations is completely identical. Similarly, the time-varying pattern of the average temperature at the armature-rail contact interface is also one of initial increase followed by decrease, with the temperature decreasing after the initial increase... x Even under zero influence, it will continue to decrease. Regardless of the launch time or the initial position of the armature, the average current density and average temperature at the center of the armature recess are greater than those at the armature-rail contact interface.

[0085] like Figure 14 As shown, Figure 14 (a) and (b) show the highest temperatures and their occurrence times at the center of the armature recess and the armature-rail contact interface under different initial armature placement positions, respectively. It can be seen that during launch, the highest temperatures at the center of the armature recess and at the armature-rail contact interface decrease with increasing initial armature placement position, and the time corresponding to the highest temperature is delayed with increasing initial armature placement position. This is due to the decrease in the peak value of the pulse current and the increase in its peak time. Specifically, the highest temperature at the center of the armature recess... xThe temperature dropped from 68.359℃ at 0=50mm to x The temperature reached 53.639℃ at 0=250mm, and the generation time also increased from 2.5ms to 6ms; the highest temperature at the pivot-rail contact interface increased from... x The temperature dropped from 39.991℃ at 0=50mm to x The temperature reached 29.892℃ at 0=250mm, and the generation time increased from 1.5ms to 3.5ms. Furthermore, the highest temperature at the center of the armature recess in each armature's initial placement position was always higher than the highest temperature at the armature-rail contact interface.

[0086] In summary, placing the armature too shallow initially may cause the electromagnetic rail launcher to generate higher temperatures, resulting in more severe ablation damage to the armature and rail, and shortening their service life. Conversely, placing it too deep initially will lead to a decrease in the armature's launch velocity and displacement, and an excessively long launch time, thus affecting the quality of the electromagnetic rail launch. Therefore, selecting a moderate value of 150mm as the initial armature placement position is more reasonable, as it can minimize the adverse effects caused by placing the armature too deep or too shallow, providing a theoretical and simulation basis for the actual placement position of the armature in subsequent electromagnetic rail launch experiments.

[0087] 2. Track materials.

[0088] The electrical, mechanical, and thermal properties of the track material have a significant impact on the performance of electromagnetic rail launchers. Selecting a high-performance track material plays a positive role in reducing current-carrying wear and various ablation damages during launch and enhancing its ability to withstand extreme impacts. With the armature initially positioned at 150mm, the differences in various properties were compared when copper, steel, copper-steel composite, copper-chromium-zirconium alloy, tungsten-copper alloy, and beryllium-copper alloy were selected. The time-domain variations of the average current density and temperature at the center of the armature recess and the armature-rail contact interface, where current density and temperature are more easily concentrated, were compared under different track materials to explore the mechanism by which the differences in track material properties affect the highest temperature during launch.

[0089] like Figure 15 As shown, Figure 15 Figures (a) and (b) show the trends of average current density and temperature at the center of the armature recess under different orbital materials. It can be seen that at the center of the armature recess, the average current density varies significantly among different orbital materials when it reaches the peak value along with the pulse current. However, as launch time progresses, the average current density of each orbital material tends to converge. At the launch moment near the peak value, the orbital material with the highest average current density is steel, followed by beryllium copper alloy, while the average current densities of the remaining four orbital materials are not significantly different. This is based on the definition of current density. J =I / S It can be seen that the fundamental reason for the difference in the average current density at the center of the armature groove under different track materials is the current flow area. S The difference lies in the material. When steel or beryllium copper alloy is used for the track, the average current density at the center of the armature recess is greater, indicating a larger area for concentrated current flow. S The smaller the conductivity, the narrower the current flow path at the center of the armature recess, resulting in a more pronounced skin effect. Therefore, we can conclude that the lower the conductivity of the track material, the stronger the skin effect at the center of the armature recess, and the higher the average current density at that location. Looking at the time-domain variation curve of the average temperature at the center of the armature recess, we find that the track material corresponding to the lowest average temperature is consistent with the current density. The track material with the highest average temperature is steel, followed by beryllium copper alloy, while the track material corresponding to the lowest average temperature is also tungsten copper alloy. However, the difference in average temperature between different track materials is not significant, with the maximum temperature difference between steel and tungsten copper alloy being less than 5°C. This is because at the center of the armature recess, the temperature rise caused by Joule heating is related to the current density at that location. Therefore, the track material has the same effect on the average current density and average temperature at the center of the armature recess: a decrease in the conductivity of the track material increases both the average current density and average temperature, but the influence of the track material on both is limited.

[0090] like Figure 16 As shown, Figure 16Figures (a) and (b) show the trends of average current density and temperature at the pivot-rail contact interface for different track materials. It can be seen that compared to the average current density and temperature at the center of the armature groove, the average values ​​at the pivot-rail contact interface are more significantly affected by the track material. Among the average current density at the pivot-rail contact interface for each track material, steel has the highest, followed by beryllium copper alloy, while copper-steel composite material has the lowest. Tungsten-copper alloy, copper-chromium-zirconium alloy, and copper are all similar. This indicates that, except for copper-steel composite material, for tracks made of other single materials, the average current density at the pivot-rail contact interface is negatively correlated with the conductivity of the track material. This is a result of the lower conductivity leading to a stronger skin effect. The average temperature at the armature-rail contact interface decreases with increasing thermal conductivity of the track material. Steel, with a low thermal conductivity of 44.5 W / m·K, has poor heat conduction and dissipation, causing high temperatures to accumulate during launch, resulting in the highest average temperature at its armature-rail contact interface among the six track materials. Copper, with a high thermal conductivity of 398 W / m·K, effectively conducts heat during launch, resulting in the lowest average temperature at its armature-rail contact interface. The temperature difference between steel and copper is nearly 20°C. Therefore, the track material has a greater impact on the average current density and temperature at the armature-rail contact interface than at the center of the armature recess. Furthermore, the average current density at this location is negatively correlated with the electrical conductivity of the track material, and the average temperature is also negatively correlated with the thermal conductivity of the track material.

[0091] like Figure 17 As shown, Figure 17Figures (a) and (b) show the maximum temperature distribution at the center of the armature groove and the armature-rail contact interface under different rail materials, respectively. It can be seen that the maximum temperature at the center of the armature groove does not differ significantly under different rail materials, fluctuating within the range of approximately 59℃ to 62℃, indicating that the rail material has little impact on the maximum temperature at the center of the armature groove. At the armature-rail contact interface, the maximum temperature corresponding to each rail material increases continuously with decreasing thermal conductivity, with the maximum temperature increasing in the following order: copper, copper-chromium-zirconium alloy, copper-steel composite, tungsten-copper alloy, beryllium-copper alloy, and steel. Among these, the maximum temperature at the armature-rail contact interface reaches 415℃ when using steel rails, which is close to the melting point of 582℃ for aluminum alloy 6061 armatures; however, the maximum temperature corresponding to the copper rail material, which has the highest thermal conductivity, is only 32.921℃. Regarding current density distribution, the current density of copper and copper-chromium-zirconium alloy rail materials is concentrated at the rear end of the pivot-rail contact interface, i.e., the position where the armature tail fin contacts the rail, due to both velocity and current skin effects. The maximum current density is also located there, but the current density is also distributed in the middle and front of the contact interface, with relatively high values. Tungsten-copper alloy weakens the velocity skin effect, resulting in a concentrated current density at the front of the pivot-rail contact interface, where the maximum current density also occurs. The current density is relatively uniformly distributed at other locations on the contact interface. The current density of beryllium-copper alloy and steel is almost entirely concentrated at the very end of the pivot-rail contact interface, where the velocity skin effect is strengthened. The current density is extremely low in the middle and front of the contact interface, and the maximum current density is higher than that of the other four rail materials. For rails made of copper-steel composite materials, the current density distribution at the pivot-rail contact interface is the most uniform. The temperature distribution at the pivot-rail contact interface for each rail material is basically consistent with the current density distribution.

[0092] In summary, for steel and beryllium copper alloy rails, the most severe armature ablation occurs at the very end of the tail fin; for tungsten copper alloy rails, melting and ablation first occur at the front end of the armature contact side; for copper and copper-chromium-zirconium alloy rails, armature ablation is distributed at both the tail fin and the front end; copper-steel composite rails, due to their more uniform temperature distribution on the armature-rail contact side, prevent the melting and ablation of the armature from concentrating in a specific location over a large area, resulting in less overall damage to the armature and rail contact surfaces. Considering material cost, copper-steel composite material was chosen as the rail material for the electromagnetic launcher in the electromagnetic rail launch system simulation experimental platform. Therefore, using 150mm as the initial armature placement position avoids both the high temperature and severe ablation caused by a shallow initial armature placement and the excessively low armature exit velocity and prolonged exit time caused by a deep initial armature placement, thus mitigating the adverse effects on the service life and launch quality of the launch experimental device. When copper-steel composite material is selected as the rail material, the temperature distribution on the contact side of the armature and rail is more uniform compared to the other five materials. The highest temperature is concentrated only at the edges of the front and rear ends of the contact interface and will not extend to the central area of ​​the contact interface. Therefore, the melting and ablation of the armature and rail contact surfaces will not be concentrated in a large area. The overall damage is the lightest among the six materials. In addition, copper-steel composite material is also cheaper when considering the typical cost index of the materials.

[0093] In this embodiment, a field-path coupling model of the electromagnetic orbital launch device was established through joint programming of equivalent circuits and multiphysics fields. The mechanical and kinematic parameters of the armature during the dynamic process of electromagnetic orbital launch were analyzed. Furthermore, the spatiotemporal dynamic distribution of current density and temperature at the center of the armature groove and the armature-rail contact interface under electromagnetic thermal field coupling was summarized. Based on the field-path coupling model, the influence of the initial armature placement position and track material—two electromagnetic orbital launch conditions—on the electrical, mechanical, and kinematic parameters of the field-path coupling model, as well as the multi-field coupling distribution characteristics, was studied. The main conclusions are as follows:

[0094] 1. Regarding the mechanical and kinematic parameters during the dynamic process of launch, the electromagnetic driving force on the armature has a quadratic function relationship with the pulse current, while the dry sliding friction force has a linear function relationship with the electromagnetic driving force. The electromagnetic driving force, dry sliding friction force, resultant force, and armature acceleration change with time in the same way as the pulse current, all of which rise rapidly to a peak and then gradually decay.

[0095] 2. Regarding the spatiotemporal distribution characteristics of the electrothermal field coupling during the launch dynamic process, the maximum current density and the highest temperature are concentrated at the center of the armature groove and the armature-rail contact interface. The current density and temperature change over time are both rapidly increasing to the peak value and then gradually decreasing, which is the same as the trend of the pulse current. However, the peak time of the current density is the same as that of the pulse current, while the time of the highest temperature is delayed.

[0096] 3. Positioning the armature deeper into the track initially increases the initial impedance of the armature-rail circuit, causing a decrease in the amplitude of the circuit pulse current waveform. This leads to a reduction in the mechanical parameters of the armature associated with the pulse current, such as electromagnetic driving force, frictional force, and resultant force, as well as kinematic parameters like acceleration, velocity, and displacement. Consequently, the armature's exit time is continuously delayed. At the center of the armature recess and the armature-rail contact interface, as the initial armature position increases, the time-domain waveform of the average current density becomes smoother, the average temperature at each moment decreases, and the highest temperature at both locations decreases with increasing initial armature position, while the time corresponding to the highest temperature is delayed. Therefore, the initial armature position in the electromagnetic orbital launch system simulation experimental platform was determined to be 150mm.

[0097] 4. The influence mechanism of six track materials on the current density and temperature distribution at the center of the armature groove and the armature-rail contact interface was investigated. The track material has a greater impact on the current density and temperature at the armature-rail contact interface than on the center of the armature groove, and the current density value is negatively correlated with the conductivity of the track material, and the temperature value is also negatively correlated with the thermal conductivity of the track material. At the armature-rail contact interface, the current density and temperature distribution is most uniform when using a copper-steel composite track; when using copper and copper-chromium-zirconium alloys, the highest temperature is distributed at the front end of the contact interface, the second highest temperature region is at the rear end of the contact interface, and the current density is mostly distributed at the rear end of the contact interface; when the track material is tungsten-copper alloy, the maximum current density and the highest temperature region are all concentrated at the front end of the armature-rail contact interface; while in the armature-rail contact interface of beryllium copper alloy and steel tracks, the maximum current density and the highest temperature are all located at the very edge of the contact interface. Therefore, the high-temperature concentration area at the armature-rail contact interface is the area most prone to severe armature ablation damage, and different track materials will cause changes in the high-temperature ablation-prone area of ​​the contact interface. This led to the determination that the track material in the electromagnetic orbital launch system simulation experimental platform is a copper-steel composite material.

[0098] The following section describes the simulation experimental platform for the electromagnetic orbital launch system and the microscopic measurement of track surface damage.

[0099] 1. Design of an electromagnetic orbital launch system simulation experimental platform.

[0100] Based on the equivalent formula constraints and simulation results of the field-circuit coupling model of the electromagnetic rail launcher, the rail of the electromagnetic launcher in the electromagnetic rail launcher simulation experimental platform uses a copper-steel composite material. Before each launch experiment, the armature is initially positioned 150mm into the barrel. The electromagnetic rail launcher simulation experimental platform is as follows: Figure 18 The system includes two pulse power supply modules, an electromagnetic rail transmitter with a copper-steel composite track, a step-up test transformer for charging the pulse power supply, a resistive voltage divider, a rectifier silicon stack, a current sensor (CT), a digital oscilloscope, a protective resistor, and a transmitting armature made of aluminum alloy 6061. The track has a rectangular aperture of 15mm × 20mm and a length of 1.2m. The inner layer, in direct contact with the armature, is made of 2mm thick structural steel, while the outer layer, used for efficient conductivity, is made of 3mm thick copper. The armature's dimensions match the track aperture, measuring 30mm × 15mm × 20mm. To ensure the equivalence and reliability of the research on the launch effect and damage conditions of the constructed experimental platform, the electromagnetic rail launch system simulation experimental platform was tested. The armature damage observed after a launch test revealed significant wear and ablation damage on both the upper and lower surfaces. Furthermore, at the moment of armature ejection, the sudden increase in contact resistance between the armature and rail generated an extremely high-energy muzzle arc at the contact interface. This arc ablation caused oxidation of the armature's aluminum alloy surface with oxygen, resulting in a black metal oxide deposit. Wear and erosion caused by high temperature and current-carrying friction were also observed at the end of the armature tail fin and the center of the groove, indicating that these two locations had the most concentrated heat distribution during the launch process, consistent with the ablation-prone areas shown in the simulation. Therefore, this electromagnetic orbital launch system simulation platform can be used to further measure and analyze the wear and ablation damage characteristics of the orbital surface, verifying the equivalence and reliability of the experimental platform. The orbital surface damage microscopic measurement system includes a scanning electron microscope (SEM), an energy dispersive spectroscopy (EDS) instrument, and a confocal laser scanning microscope (CLSM). It can effectively observe the microscopic morphology and elemental composition of the track surface after electromagnetic launch experiments, and extract the three-dimensional contour surface characteristics, thereby determining the type of track surface wear and ablation damage, and obtaining the track damage development law and severity under different working conditions.

[0101] 2. Characteristics of cumulative wear and ablation damage on track surface under different working conditions.

[0102] 2.1 Track sampling location.

[0103] To investigate the influence of the number of launch experiments and the peak pulse current on the cumulative wear and ablation damage characteristics of the track surface, three sets of electromagnetic track launch experiments were conducted under different conditions using an electromagnetic track launch system simulation platform. The first set of conditions involved charging the pulse power supply to 2000V, obtaining a peak pulse current of 40kA, with one launch experiment. The second set involved charging the pulse power supply to 5500V, obtaining a peak pulse current of 130kA, with one launch experiment. The third set involved charging the pulse power supply to 2000V, obtaining a peak pulse current of 40kA, with ten launch experiments. After completing the three sets of launch experiments, the inner steel track material inside the electromagnetic launcher was removed. Based on the macroscopic damage level and aluminum deposition on the track surface, track segment samples were selected at four typical damage locations along the track length, each segment being 20mm in length. Position 1 is located at the starting point of armature firing, i.e., the initial position of the armature placement, 150mm from the end of the track; Position 2 is located 375mm from the end of the track; Position 3 is located 945mm from the end of the track; Position 4 is located at the very beginning of the track, i.e., the muzzle, 1200mm from the end of the track. The tracks for the three sets of firing experiments under specific working conditions are named Track 1, Track 2, and Track 3, respectively; the four positions in Track 1 are named R1-1, R1-2, R1-3, and R1-4, respectively, along the armature firing direction; using the same naming method, the selected samples of Track 2 and Track 3 are named R2-1, R2-2, R2-3, R2-4 and R3-1, R3-2, R3-3, R3-4, respectively.

[0104] In orbits 1 and 2, at position 1, which serves as the starting point for armature launch, the orbital surface is primarily covered with dense transverse scratches and grooves along the launch direction. Due to the lower armature speed and longer contact time with the orbit at this location, the current-carrying frictional wear at the armature-rail interface is more severe. Therefore, the ablation damage at this location is mainly characterized by current-carrying friction and its accompanying groove ablation, and a grayish-white deposited aluminum layer has begun to adhere to the orbital surface. Subsequently, when the armature moves to position 2, the transverse scratches and grooves become more numerous and denser, and the coverage area of ​​the deposited aluminum layer also expands. The large size indicates that the friction, wear, and groove erosion of the track at this location are becoming increasingly severe. Localized high temperatures and stresses cause the armature aluminum alloy material to soften, melt, and solidify on the track surface. However, at position 3 in the front part of the track, the effective damaged area is reduced, and the wear and erosion on the track surface are somewhat alleviated. The transverse scratches become sparser, and the area covered by the deposited aluminum layer also decreases, concentrated only in a few scratch grooves. This is because when the armature moves to the latter half of the track, it has already begun to move at high speed, and its speed... v AAs the armature approaches its peak value, the contact time with the rail decreases. Furthermore, the formation of a liquefied metal layer on the armature surface under high temperature significantly reduces the friction coefficient and stress at the armature-rail interface, ultimately weakening current-carrying frictional wear and groove ablation damage. Finally, at the moment the armature leaves the barrel, at muzzle position 4 (e.g., in R1-4), a clear area of ​​black carbonized and oxide deposits can be seen at the very front of the rail. This is caused by the high-temperature ablation of the muzzle arc, with the most severe wear and ablation damage occurring at the muzzle. Besides the transverse scratches and groove ablation, there is also planing ablation that creates several pits. For rail 3, which has undergone 10 firing tests, extremely severe damage is clearly observed at various points along the rail. It not only has large areas of transverse scratches but also traces of black carbonized and oxide layers from arc ablation, indicating that the increased number of firings leads to severe wear on the rail surface, with transition and arc ablation already occurring at various points along the rail before the muzzle.

[0105] In summary, the macroscopic characteristics of track damage are as follows: the degree of damage gradually increases in the rear section of the track, accompanied by a continuous expansion of the damaged area; then it continuously weakens in the front section of the track, with a slight decrease in the proportion of the damaged area; finally, arc ablation occurs at the muzzle, causing the damage to intensify again and reach the most severe level along the entire track. However, with the increase in the number of firing experiments, arc ablation will spread from the muzzle to other locations on the track.

[0106] 2.2 Pulse current peak value.

[0107] The damage at various locations on two tracks under different pulse current peak conditions was examined using a track surface damage micro-measurement system. First, the microscopic morphology, aluminum content, and distribution of the damaged surfaces of tracks 1 and 2 were obtained using SEM and EDS. The results showed that, for both tracks 1 and 2, various damage morphologies existed at four locations along the same track along the firing direction. Obvious transverse grooves or mottled protrusions were observed in R1-1 and R2-1; cloud-like wrinkles formed by aluminum agglomeration were present in R1-2 and R2-2; scattered pits and deposited aluminum shavings caused by ablation were present in R1-3 and R2-3; and large nodular structures composed of aluminum and its oxides were formed at the muzzle in R1-4 and R2-4. EDS measurements show that aluminum is concentrated on prominent ridges in the microstructure of the track surface. The content is relatively low at position 1, the initial location of the armature. Aluminum content increases with continuous deposition along the launch direction. Furthermore, as the peak pulse current increases, under stronger electromagnetic-thermal-physical coupling and extreme impact, the armature will shed more aluminum, which will then deposit and condense on the track surface, increasing its roughness.

[0108] Then, full-domain scanning imaging and roughness parameter calculation were performed on all segment samples using CLSM. According to the CLSM test results, under the condition of a pulse current peak of 40kA and one launch experiment, the three-dimensional contour shape of track 1 in segment R1-1 is mainly characterized by transverse grooves and transverse peaks overlapping along the launch direction. The transverse grooves are caused by the current-carrying friction and wear between the armature and the track at the beginning of the movement, and the strong local friction causes the track surface material to be scraped and lost. The formation mechanism of the transverse peaks is that under the action of preload pressure, when the armature begins to accelerate, there is transverse shear stress at the armature-track contact interface. The aluminum elements on the armature surface are peeled off by the shear stress and adhere to the track surface to form a deposited aluminum layer. Along the launch direction at R2-2, in front of R1-1, the distribution of grooves and peaks on the track surface is more complex and undulating. The area of ​​the peaks formed by the deposited aluminum layer is larger than that of R1-1, indicating that the wear and ablation at this location are more severe, and the armature is more likely to undergo multiple material phase transformation reactions and produce more deposited aluminum layers. At position R1-3, the deposited aluminum layer almost completely covers the selected surface area, and its thickness has significantly increased. Arc erosion pits formed by transition ablation are clearly visible on the deposited aluminum layer. Therefore, it can be determined that when the armature moves to the position near the muzzle, the aluminum on the armature surface has undergone large-scale consumption under the coupled effects of high temperature and high stress. The molten aluminum, after cooling, re-adheres onto the track surface, thus expanding the area of ​​the deposited aluminum layer. The loss of material on the armature contact surface leads to the formation of a plasma gap between the armature and track interface. When the potential between the armature and track exceeds the breakdown voltage of the gap, an arc discharge occurs in the gap, thus entering the transition ablation stage. At the muzzle position R1-4, due to the presence of multiple types of damage, including the most severe arc ablation, the track surface profile is more undulating, irregular, and exhibits a variety of damage morphologies.

[0109] When the peak pulse current increases to 130kA, the three-dimensional profile of track 2 differs significantly from that of track 1. At points R2-1 and R2-2, compared to the same location on track 1, the surface profile becomes more chaotic and uneven, with larger maximum profile peak heights and valley depths, and a greater number of peaks and pits. At point R2-3, the thickness and coverage area of ​​the deposited aluminum layer attached to the surface decrease, exposing the rough surface of the track after wear and ablation damage. This is because the increased peak pulse current leads to a faster armature speed and more heat generation, causing the molten aluminum to splash away before it can adhere to the track surface, or even vaporize at the higher temperatures generated by the arc discharge.

[0110] like Figure 19The diagram shows a comparison of the root mean square (RMS) heights of the surfaces of tracks 1 and 2. It can be seen that along the firing direction, from the initial armature placement position 1 at the end of the track to the muzzle position 4 at the foremost end, the three-dimensional profile RMS height of the track surface continuously increases, indicating a continuous increase in roughness. The RMS height is lowest at position 1, with the lowest roughness, while the roughness is highest at position 4. This demonstrates that when the pulse current peak is 40 kA and the firing experiment is repeated once, as the degree of damage to the track surface intensifies and the deposited aluminum layer continues to expand, the roughness at various locations on the track surface continuously increases along the firing direction. When the pulse current increases to 130kA, the roughness at various locations along the track length generally continues to increase. However, at position 3 near the muzzle of track 2, the roughness shows a significant decrease. This is mainly because at position 3 on track 1, although the deposited aluminum layer is relatively smooth, the bulges in the deposited aluminum layer and the ablation pits caused by the transition arc coexist, resulting in the maximum profile peak height and maximum profile valley depth occurring on the same track surface, leading to an overestimation of the calculated root mean square height. At position 3 on track 2, under the influence of higher pulse current peaks and extreme firing conditions, the deposited aluminum layer on the track surface is either melted and vaporized by high temperatures or peeled off and splashed by the relative displacement of the high-speed moving armature, leading to the continuous consumption of the deposited aluminum layer. Finally, a relatively smooth track surface is exposed, with a smaller peak-to-valley difference, resulting in a smaller calculated root mean square height. Finally, at position 4 near the muzzle, the roughness of track 2 is also lower than that of track 1, for the same reason as the difference in roughness between the two tracks at position 3.

[0111] 2.3 Number of launch experiments.

[0112] By comparing the macroscopic damage morphology of track 1 and track 3, it can be found that with the increase of the number of launch experiments, the macroscopic damage of track 3 is more severe than that of track 1. The transverse scratches at various locations become denser and more numerous due to the accumulation of wear and ablation, and are distributed almost throughout the entire pivot-track contact interface. The coverage area of ​​the deposited aluminum layer also extends to the entire contact interface. Gouging ablation begins earlier at position 3, forming a clearly visible teardrop-shaped deep pit. Furthermore, the ablation damage at position 4 is extremely severe due to repeated arc ablation at the muzzle. Arc ablation spreads to various locations along the entire track, and the surface becomes more uneven due to material loss and aluminum deposition.

[0113] Similarly, the damage at various locations on track 3 was examined using a track surface damage micro-measurement system. It can be seen that as the number of launches increased from 1 to 10, the aluminum layer deposited on the track surface thickened continuously, and the distribution and content of aluminum elements increased significantly. The micro-morphology of the track surface became extremely complex due to the cumulative damage from repeated launch experiments. In the four locations from the breech to the muzzle, a complex morphology was formed where deep pits caused by wear and ablation coexisted with bulges caused by the accumulation of aluminum layers. For example, at R3-1, the initial position of the armature placement, the regular transverse grooves in R1-1, which had only been launched once, were no longer present. Instead, the morphology was more fragmented and rugged.

[0114] Subsequently, a laser scanning confocal microscope was used to perform full-domain scanning imaging and roughness parameter calculation on four sections of track 3. The results showed that, compared with the three-dimensional contour morphology of track 1, the morphology at four locations in track 3 was more complex due to the significantly increased number of launch experiments. Multiple micromorphologies coexisted, including deep pits and holes caused by ablation, protruding ridges formed by condensed aluminum chips, and narrow grooves scraped by friction and wear. This resulted in a significant increase in the difference between the maximum contour peak height and the maximum contour valley depth, leading to a substantial increase in surface roughness. Specifically, at R3-2, due to multiple armature launches, aluminum elements from the armature contact surface were repeatedly peeled off and deposited on the track surface during each launch experiment, resulting in a thicker aluminum deposition layer. At R3-3, the originally smooth aluminum deposition layer from a single launch became more fragmented and irregularly distributed due to the additional wear and ablation.

[0115] like Figure 20 The diagram shows a comparison of the root mean square height of the surfaces of tracks 1 and 3. It can be seen that the increased number of launches directly leads to a significant increase in the surface roughness of the tracks, particularly at positions 1 and 4, i.e., the initial armature placement position and the muzzle. This is because at armature placement position 1, the armature overcomes various stresses to transition from a stationary state to accelerated motion during each launch experiment. In repeated launch experiments, as the surface roughness of the tracks increases, the shear stress between the armature and the track increases, requiring the armature to overcome greater stress to launch. This motion transition process causes greater mechanical wear and groove erosion on the track surface, resulting in more fatigue cracks and a significant increase in roughness. The arc erosion at muzzle position 4 is the most severe; the accumulated arc erosion damage from multiple repeated launch experiments causes continuous and significant damage to the muzzle track, greatly increasing the surface roughness at this location.

[0116] Therefore, the increased surface roughness of the track after multiple launch experiments will continuously worsen the experimental environment of electromagnetic track launch. The wear and ablation between the pivot and the track during launch will seriously affect the quality and efficiency of electromagnetic launch. If the track cannot be replaced in time or an effective method to suppress the surface roughness of the track cannot be adopted, it will not only drastically reduce the service life of the electromagnetic track launcher, but may also pose a great threat to the safety of the instruments and equipment and the experimental personnel.

[0117] In this embodiment, based on the equivalent simulation criteria and simulation results of the field-path coupling model of the electromagnetic orbital launch device, a simulation experimental platform for the electromagnetic orbital launch system, which is mapped to the model, was established, and the launch conditions were optimized: the initial position of the armature was determined to be 150mm deep into the track, and the track material of the electromagnetic launcher was determined to be a copper-steel composite material. A microscopic measurement system for track surface damage, composed of scanning electron microscopy (SEM) and laser scanning confocal microscopy (CLSM), was used to compare and analyze the microstructure, aluminum element distribution and content, and surface roughness at different positions of the track under different launch experimental conditions. The main conclusions are as follows:

[0118] 1. From a macroscopic morphological perspective, the surface wear and ablation damage types on the same track are mainly current-carrying friction wear and groove ablation. Based on the macroscopic effective damage area of ​​each sample, the macroscopic characteristics can be summarized as follows: the damage degree initially increases and then decreases from the rear end to the front end of the track, finally reaching the most severe level across the entire track due to arc ablation at the muzzle. However, with the increase in the number of firing tests, the track surface wear becomes severe, causing arc ablation to spread from the muzzle to the rear and middle sections of the track.

[0119] 2. From the perspective of microscopic morphology, based on the observation images of SEM and CLSM, there are different damage morphologies at various locations on the same track. In particular, the arc ablation that occurs at the muzzle will cause large nodular tissue to accumulate, and its surface roughness is the maximum value of the entire track. The distribution of aluminum is concentrated in the protruding ridges in the microscopic morphology of the track surface, and aluminum will continue to be deposited on the track surface along the launch direction.

[0120] 3. As the peak value of the pulse current increases, the macroscopic damage area with transverse scratches on the track surface will increase, and the microscopic morphology will have more peaks and pits, making the three-dimensional profile more complex. In particular, at the track tip and muzzle, due to the splashing and vaporization of aluminum chips caused by the high temperature of the strong current, the thickness and area of ​​the deposited aluminum layer on the surface will decrease, and the roughness at these two locations will show a significant decrease.

[0121] 4. As the number of launch tests increases, the macroscopic damage to the track surface becomes more severe due to repeated wear and ablation. Water droplet-shaped pits formed by planing and ablation can be observed. The muzzle is severely damaged due to repeated arc ablation, which spreads to various locations along the entire track. The microscopic morphology of the track surface also becomes extremely complex due to accumulated damage, with the deposited aluminum layer continuously thickening and the distribution and content of aluminum elements greatly increasing. The surface roughness at various locations along the track also increases significantly, especially at the initial armature placement position and the muzzle.

[0122] Example 2

[0123] This embodiment provides an electromagnetic track damage detection system based on multi-field coupling analysis, including:

[0124] The model building module is configured to build an equivalent circuit model of the electromagnetic orbital launch device and an electromagnetic-thermal multiphysics coupling model.

[0125] The coupling module is configured to acquire the armature loop pulse current, armature mechanical parameters and armature kinematic parameters obtained after launching simulation of the equivalent circuit model, and import them into the electromagnetic-thermal multiphysics coupling model to obtain the field-circuit coupling model of the electromagnetic track launch device.

[0126] The analysis module is configured to obtain the distribution patterns of current density and temperature along the boundary of the armature contact interface and the inner boundary of the armature groove during the launch simulation under electromagnetic and thermal multi-physics field coupling, thereby determining the concentrated distribution location when the current density and temperature are highest.

[0127] The optimization module is configured to determine the optimal initial position for armature placement based on the changes in armature rail circuit pulse current, armature mechanical parameters, armature kinematic parameters, and current density and temperature at the concentrated distribution location under different initial armature placement positions. Furthermore, under the optimal initial position, the optimal rail material is determined based on the changes in current density and temperature at the concentrated distribution location under different electromagnetic transmitter rail materials.

[0128] The detection module is configured to build a simulation experimental platform for the electromagnetic track launch system based on the optimal initial position of the armature and the optimal track material of the electromagnetic transmitter, so as to test the surface damage at different positions of the track under different pulse current peaks and launches.

[0129] In further embodiments, the following is also provided:

[0130] An electronic device includes a memory and a processor, as well as computer instructions stored in the memory and running on the processor, wherein the computer instructions, when executed by the processor, perform the method described in Embodiment 1.

[0131] A computer-readable storage medium for storing computer instructions, which, when executed by a processor, perform the method described in Embodiment 1.

[0132] A computer program product includes a computer program that, when executed by a processor, implements the method described in Embodiment 1. For the sake of brevity, further details are omitted here.

[0133] The above content is not intended to limit the scope of protection of this invention. Based on this invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of this invention.

Claims

1. A method of electromagnetic rail damage detection by multi-field coupling analysis, characterized by, The application relates to a method for determining an optimal initial position of an armature and an optimal track material of an electromagnetic launcher. The method comprises the following steps: building an equivalent circuit model and an electromagnetic-thermal multi-physical field coupling model of the electromagnetic launcher; obtaining the armature mechanical parameters, the armature kinematic parameters and the armature force of the armature obtained by the equivalent circuit model, and importing the armature mechanical parameters, the armature kinematic parameters and the armature force into the electromagnetic-thermal multi-physical field coupling model to obtain a field-circuit coupling model of the electromagnetic launcher; obtaining the distribution rules of the current density and the temperature along the armature-track contact interface boundary and the armature recess inner boundary in the process of the electromagnetic-thermal multi-physical field coupling, and determining the concentrated distribution position of the current density and the temperature according to the distribution rules; determining the optimal initial position of the armature according to the changes of the armature mechanical parameters, the armature kinematic parameters, the armature force and the current density and the temperature at the concentrated distribution position under different initial positions of the armature, and determining the optimal track material according to the changes of the current density and the temperature at the concentrated distribution position under different track materials of the electromagnetic launcher; building an electromagnetic launcher system simulation experiment platform according to the optimal initial position of the armature and the optimal track material of the electromagnetic launcher, and testing the surface damage of the track at different positions under different pulse current peak values and different numbers of launches; the process of testing the surface damage of the track at different positions under different pulse current peak values and different numbers of launches comprises the following steps: comparing and analyzing the micro-morphology, the aluminum element distribution and content and the surface roughness of the track at different positions under different pulse current peak values and different numbers of launches, and obtaining the wear and ablation damage characteristics of the surface of the high-speed sliding track under strong current; from the macro-morphology, the surface wear and ablation damage types of the same track include current-carrying friction wear and groove ablation, the damage degree presents a trend of first increasing and then decreasing from the rear end to the front end of the track, finally, arc ablation occurs at the muzzle position to re-enhance and reach the most serious level in the whole track, and with the increase of the number of launch experiments, the surface wear degree of the track is serious, and arc ablation spreads from the muzzle to the rear and middle positions of the track; from the micro-morphology, the arc ablation at the muzzle position leads to the aggregation of tumor tissues, and the surface roughness is the maximum value of the whole track; the aluminum element is concentrated in the protruding bumps in the micro-morphology of the track surface, and the aluminum element on the track surface continuously deposits along the launch direction; with the increase of the pulse current peak value, the macro-damage area of the track surface with transverse scratches increases, the micro-morphology distribution has more peaks and pits, the thickness and area of the deposited aluminum layer on the surface of the front end and the muzzle position of the track decrease, and the roughness decreases; 2. A multi-field coupled analytical electromagnetic rail flaw detection method according to claim 1, wherein, with the increase of the number of launch experiments, arc ablation spreads to all positions of the whole track, the deposited aluminum layer thickens, the aluminum element distribution and content increase, and the surface roughness of all positions of the track increases. The armature mechanical parameters include the electromagnetic driving force, the dry sliding friction force and the resultant force of the armature, and the armature kinematic parameters include the armature motion acceleration, the armature motion speed and the armature displacement. Among them, the electromagnetic driving force and the armature circuit pulse current have a quadratic function relationship, while the dry sliding friction force and the electromagnetic driving force have a linear function relationship. The electromagnetic driving force, dry sliding friction force, resultant force, and armature acceleration change with time in the same way as the armature circuit pulse current. They all gradually increase during the rising phase of the armature circuit pulse current, reach their maximum values ​​at the same time as the armature circuit pulse current, and then decay. The moment when the armature acceleration reaches its maximum value is also the moment when the armature circuit pulse current and various armature mechanical parameters reach their peak values. The armature velocity and armature displacement show a continuous growth pattern during the armature motion process.

3. The electromagnetic rail defect detection method of claim 1, wherein, The locations where the current density and temperature are highest are determined to be the center of the armature groove and the armature-rail contact interface. The variation patterns of current density and temperature over time are the same as the variation trends of the armature-rail circuit pulse current, and the peak time of current density is the same as that of the armature-rail circuit pulse current, while the time of the highest temperature is delayed.

4. The electromagnetic rail defect detection method of multiple field coupling analysis as claimed in claim 1, wherein, At the center of the armature groove and the contact interface with the armature rail, as the initial position of the armature increases, the time-domain waveform of the average current density becomes smoother, the average temperature at each moment decreases, and the highest temperature at both locations decreases as the initial position of the armature increases. The moment corresponding to the highest temperature is delayed as the initial position of the armature increases. Therefore, the optimal initial position for armature placement is determined to be 150 mm. Based on the different electromagnetic transmitter track materials, the effects of current density and temperature changes at the center of the armature groove and the armature-rail contact interface were investigated. The current density value was negatively correlated with the electrical conductivity of the track material, and the temperature value was negatively correlated with the thermal conductivity of the track material. The optimal track material was determined to be a copper-steel composite material.

5. A multi-field coupled analysis electromagnetic rail flaw detection system, characterized by, An electromagnetic track damage detection method for implementing the multi-field coupling analysis according to any one of claims 1-4 includes: The model building module is configured to build an equivalent circuit model of the electromagnetic orbital launch device and an electromagnetic-thermal multiphysics coupling model. The coupling module is configured to acquire the armature loop pulse current, armature mechanical parameters and armature kinematic parameters obtained after launching simulation of the equivalent circuit model, and import them into the electromagnetic-thermal multiphysics coupling model to obtain the field-circuit coupling model of the electromagnetic track launch device. The analysis module is configured to obtain the distribution patterns of current density and temperature along the boundary of the armature contact interface and the inner boundary of the armature groove during the launch simulation under electromagnetic and thermal multi-physics field coupling, thereby determining the concentrated distribution location when the current density and temperature are highest. The optimization module is configured to determine the optimal initial position for armature placement based on the changes in armature rail circuit pulse current, armature mechanical parameters, armature kinematic parameters, and current density and temperature at the concentrated distribution location under different initial armature placement positions. Furthermore, under the optimal initial position, the optimal rail material is determined based on the changes in current density and temperature at the concentrated distribution location under different electromagnetic transmitter rail materials. The detection module is configured to build a simulation experimental platform for the electromagnetic track launch system based on the optimal initial position of the armature and the optimal track material of the electromagnetic transmitter, so as to test the surface damage at different positions of the track under different pulse current peaks and launches.

6. An electronic device, comprising: It includes a memory and a processor, as well as computer instructions stored in the memory and running on the processor, which, when executed by the processor, perform the method according to any one of claims 1-4.

7. A computer readable storage medium characterized in that, Used to store computer instructions, which, when executed by a processor, perform the method described in any one of claims 1-4.

8. A computer program product, characterised in that, Includes a computer program, which, when executed by a processor, implements the method described in any one of claims 1-4.

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