Multi-body dynamics calculation method and system for high-speed rocket sled-orbit system

Abstract

The invention discloses a multi-body dynamics calculation method and system for a high-speed rocket sled-orbit system, and the method comprises the steps: building a flexible rocket sled dynamics model, and verifying the flexible rocket sled dynamics model through a rocket sled modal test; establishing a flexible track dynamic model, and verifying the flexible track dynamic model through a track modal test; establishing a shoe-rail interaction kinetic model; engine thrust, aerodynamic resistance and mass time-varying propellant models are established respectively, a flexible rocket sled dynamic model, a flexible track dynamic model and a shoe-track interaction dynamic model are combined to establish a rocket sled-track system multi-body dynamic model, and the rocket sled-track system multi-body dynamic model is solved through numerical values; and obtaining the dynamic response of the rocket sled. Rapid and high-precision rocket sled dynamic response prediction is realized, the design of the rocket sled is optimized, and the development cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of multi-body dynamics, and in particular relates to a multi-body dynamics calculation method and system for a high-speed rocket sled-track system. Background Art

[0002] The rocket sled-track system is a large-scale, high-precision ground test equipment. The rocket sled is propelled by a solid rocket engine and continuously accelerates along a highly straight track, reaching supersonic or even hypersonic speeds. During the acceleration process or after reaching the required speed, the performance of the test object installed on the rocket sled can be evaluated. The part of the rocket sled that is in direct contact with the track is called a skid, which wraps the track to prevent the rocket sled from derailing during movement. In order to meet the installation requirements, a gap is left between the skid and the track, which also causes a series of collisions and separations between the skid and the track. These intermittent contacts will cause severe vibrations of the rocket sled and the track, so the vibration environment experienced by the rocket sled and the track is extremely harsh. The huge dynamic loads between them may cause the rocket sled to disintegrate, the track to break, or even the engine to explode. Therefore, in order to accurately predict the dynamic response of the rocket sled before the rocket sled test, it is of great significance to establish a dynamic simulation method for the high-speed rocket sled-track system.

[0003] There are currently two types of dynamic simulations for high-speed rocket sled-track systems. The first type aims to obtain the dynamic response of the rocket sled at a specific driving speed. The simulation time is 10 -3 Seconds to 10 -2 The first type is to simulate the entire process of the rocket sled accelerating to the maximum speed. The simulation time ranges from 1 second to 10 seconds, and the distance the rocket sled moves is usually more than 1 kilometer. For this type, due to the long simulation time, the amount of calculation needs to be considered, and the multi-body dynamics method is usually used to model the system. Through the multi-body dynamics method, it is possible to predict the dynamic behavior of the rocket sled that is constantly evolving during the test, and all nonlinear factors of the system can be considered in the modeling.

[0004] In all current multi-body dynamics simulation methods for high-speed rocket sled-track systems, one of the rocket sled and the track is modeled as a rigid body due to computational considerations.

[0005] Regarding the track, modeling kilometers of track as a flexible body while considering multiple contact points between the slider and the track will result in huge computational costs. However, it is unreasonable to treat the track as a rigid body. When subjected to large contact forces, the track vibrates and generates elastic waves, which propagate to other locations on the track. Since the speed of the rocket sled is usually lower than the propagation speed of the elastic waves, the track segment that is about to contact the rocket sled slider has been affected by the elastic waves, vibrates, and deforms elastically. The deformation of the track significantly affects the boundary conditions of the slider, which in turn affects the dynamic response of the rocket sled and the track. This shows the importance of treating the track as a flexible body for accurate simulation.

[0006] As for the rocket sled, it is also inappropriate to model the rocket sled as a rigid body, because the first-order natural frequency of the rocket sled is often lower than the first-order natural frequency of the track, that is, the rocket sled is more flexible than the track.

[0007] In general, existing modeling methods that treat rocket sleds or tracks as rigid bodies oversimplify the interaction between the two and ignore the relevant dynamic effects. Therefore, the disadvantage of existing simulation methods is that their accuracy cannot be evaluated and there is a lack of experimental verification. The reason for this disadvantage is that these simulation methods sacrifice computational accuracy in order to improve computational efficiency. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a multi-body dynamics calculation method and system for a high-speed rocket sled-track system in view of the deficiencies in the above-mentioned prior art, which is used to solve the technical problem of dynamic response prediction of the entire acceleration process of the rocket sled. By establishing a semi-fidelity flexible rocket sled and flexible track model, the huge computational complexity problem caused by flexible modeling is overcome, and a balance is achieved between computational accuracy and efficiency. Before the high-speed rocket sled test, a fast and high-precision prediction of the dynamic response of the rocket sled is achieved, thereby optimizing the design of the rocket sled and reducing the development cost.

[0009] The present invention adopts the following technical solutions:

[0010] A high-speed rocket sled-track system multi-body dynamics calculation method comprises the following steps:

[0011] The dynamic model of the flexible rocket sled is established and verified through the rocket sled modal test;

[0012] Establish a flexible track dynamic model and verify it through track modal tests;

[0013] Establish the dynamic model of shoe-rail interaction;

[0014] The engine thrust, aerodynamic drag and mass time-varying propellant models are established respectively. The multi-body dynamic model of the rocket sled-track system is established by combining the obtained flexible rocket sled dynamic model, flexible track dynamic model and shoe-track interaction dynamic model. The dynamic response of the rocket sled is obtained by numerically solving the multi-body dynamic model of the rocket sled-track system.

[0015] Preferably, the flexible rocket sled dynamics model is established as follows:

[0016] According to the specific rocket sled structure and parameters, establish the nodes corresponding to each substructure;

[0017] According to the connection relationship between each substructure, finite volume beam elements, multi-degree-of-freedom spring-damper elements and various sub-elements are used to connect each node to obtain the dynamic model of the rocket sled;

[0018] The established rocket sled dynamic model is characterized by analysis, and the calculated modal parameters are obtained, which are then verified based on the experimental modal parameters obtained from the rocket sled modal test.

[0019] Preferably, the finite volume beam element includes a limited influence region of two end nodes; at each evaluation point of the finite volume beam element, a linear viscoelastic constitutive law is used to describe the relationship between the generalized internal force and the generalized beam strain and its time derivative, specifically:

[0020]

[0021] Among them, F x is the axial force, F y and F z is the tangential force, M x is the torsional moment, M y and M z is the bending moment, ε x is the axial strain, γ y and γ z is the shear strain, κ x is the torsional curvature, κ y and κ z is the bending curvature. The superscript “·” indicates the time derivative of the physical quantity, K is the stiffness matrix of the evaluation point, P C is the proportional damping factor.

[0022] Preferably, the flexible track dynamics model is established as follows:

[0023] Establish a computational dynamics model for flexible track cycles;

[0024] According to the specific track structure and parameters, the nodes corresponding to each substructure of the flexible track in each cycle are established;

[0025] According to the connection relationship between the substructures of the track in each cycle, finite volume beam elements, multi-degree-of-freedom spring-damper elements and various sub-elements are used to connect the nodes;

[0026] Conduct characteristic analysis on the established flexible track dynamics model to obtain the calculated modal parameters, and verify it based on the experimental modal parameters obtained from the track modal test;

[0027] The power spectral density of the measured short-distance track irregularity data is calculated, and the long-distance track irregularity is reconstructed through randomized phase and applied to the flexible track dynamics model.

[0028] Preferably, the flexible track dynamic model adopts a discrete double-layer structure; the six degrees of freedom of all ground nodes are fixed; each track segment contains two supporting track nodes and three equidistant intermediate track nodes; adjacent track segments are connected by a common supporting track node; each track node is connected by a finite volume beam unit; and a 6D viscoelastic unit connects the track and pillow plate nodes, as well as the pillow plate nodes and the ground nodes.

[0029] Preferably, the shoe-rail interaction dynamics model is established as follows:

[0030] One sliding point node is established on the front and rear sides of each sliding shoe;

[0031] According to the contact surface shape of each sliding shoe, each potential contact point is defined respectively, the contact point on the sliding shoe is fixedly connected to the sliding shoe node, and the contact point on each side of the sliding shoe on the track is fixedly connected to the corresponding sliding point;

[0032] According to the relationship between the relative displacement and relative velocity between each contact point pair and combined with the Flores contact model, the normal contact force model and the tangential contact force model between each contact point pair are established.

[0033] Preferably, the sliding node has no mass and moment of inertia, and is used to describe the contact force between the sliding shoe and the track; the movement of the sliding node in the heading is consistent with the corresponding sliding shoe, and is maintained on the track axis through the beam-sliding unit; the beam-sliding unit restricts the sliding node from sliding along a series of finite volume beams, while transmitting the contact force between the track beam and the sliding node at each contact point.

[0034] Preferably, the engine thrust, aerodynamic drag, and mass time-varying propellant models are established respectively as follows:

[0035] Establish an engine thrust model; according to the factory thrust curve of the engine, apply the thrust time history curve to the nozzle node, along the positive direction of the heading;

[0036] Establish an aerodynamic drag model; use computational fluid dynamics methods to calculate the aerodynamic drag of each rocket sled node;

[0037] A mass time-varying propellant model is established. According to the structural parameters of solid rocket propellant, the relationship between the mass and moment of inertia of each propellant node and time is solved and assigned to each propellant node.

[0038] A multi-body dynamics model of the rocket sled-track system is established based on the flexible rocket sled dynamics model, flexible track dynamics model, shoe-track interaction dynamics model, and the engine thrust model, aerodynamic drag model, and mass time-varying propellant model.

[0039] The differential-algebraic equations corresponding to the multi-body dynamics model of the rocket sled-track system are solved to obtain the dynamic response of the rocket sled during the entire acceleration process along the track.

[0040] Preferably, the differential-algebraic equations corresponding to the multi-body dynamics model of the rocket sled-track system are solved as follows:

[0041] First, the initial derivatives of the system of equations are solved; in the first solution step, the Crank-Nicolson single-step integration method is used to start the calculation program;

[0042] In the subsequent solution steps, the double-step backward difference method is used.

[0043] In a second aspect, an embodiment of the present invention provides a high-speed rocket sled-track system multi-body dynamics calculation system, comprising:

[0044] Rocket sled module, establishes a flexible rocket sled dynamic model, and verifies the flexible rocket sled dynamic model through rocket sled modal tests;

[0045] Track module, establishes a flexible track dynamic model and verifies the flexible track dynamic model through track modal tests;

[0046] Shoe-rail module, to establish the shoe-rail interaction dynamics model;

[0047] The output module establishes engine thrust, aerodynamic drag, and mass time-varying propellant models respectively, and combines the obtained flexible rocket sled dynamics model, flexible track dynamics model, and shoe-track interaction dynamics model to establish a multi-body dynamics model of the rocket sled-track system. The dynamic response of the rocket sled is obtained by numerically solving the multi-body dynamics model of the rocket sled-track system.

[0048] In a third aspect, a computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned high-speed rocket sled-track system multi-body dynamics calculation method when executing the computer program.

[0049] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, comprising a computer program, which, when executed by a processor, implements the steps of the above-mentioned high-speed rocket sled-track system multi-body dynamics calculation method.

[0050] Compared with the prior art, the present invention has at least the following beneficial effects:

[0051] A multi-body dynamics calculation method for a high-speed rocket sled-track system can achieve rapid and accurate prediction of the dynamic response of a flexible rocket sled during the entire process of accelerating to supersonic speed along a kilometer-level flexible track.

[0052] Furthermore, compared with the rigid rocket sled dynamics model, establishing a flexible rocket sled dynamics model can more realistically and comprehensively reflect the deformation of the rocket sled after being subjected to force, and help capture the influence of its own dynamic characteristics (such as natural frequency, vibration mode, etc.) in the dynamic response, thereby providing more accurate simulation results.

[0053] Furthermore, compared with the traditional finite element discretization of beams, the finite volume discretization of C0 type (adjacent unit boundaries have zero-order continuity) beams is less prone to shear self-locking; the three-node finite volume discretization of beams has been proven to be free of shear self-locking. In view of the specific problem of the present invention, the rail (flexible beam) bends after being subjected to the collision force of the sliding shoe. Shear self-locking refers to excessive rigidification during the bending process of the unit, resulting in excessive calculated shear stress and too small bending deformation. The finite element method needs to deal with this problem through methods such as the reduced integral method, while the finite volume method essentially solves this problem, and is therefore very suitable for the discretization of flexible rails within the scope of multi-body dynamics. In addition, the finite volume method discretizes the beam into a series of control bodies, and the internal forces and internal moments of each control body are only evaluated at the boundaries of the control body, thereby simplifying their contribution to the equilibrium equation, which is beneficial to improving computational efficiency.

[0054] Furthermore, compared with the rigid track dynamics model, the establishment of a flexible track dynamics model is helpful to obtain the dynamic response of the track and a more accurate dynamic response of the rocket sled. Specifically, during the movement of the rocket sled, the sliding shoe will intermittently hit the track, thereby exciting elastic waves in the track, and the elastic waves will propagate to other positions of the track. Since the maximum speed of existing rocket sleds at home and abroad is lower than the wave speed of elastic waves in the rails, the track point that the rocket sled is about to reach has been affected by the elastic wave and vibrates and produces elastic deformation, and even the vibration of the track point is the result of the superposition of multiple elastic waves generated by multiple shoe-track contacts. The vibration and elastic deformation of the track change the original track unevenness, affect the boundary conditions of the sliding shoe, and then affect the dynamic response of the rocket sled. The change in the dynamic response of the rocket sled in turn affects the subsequent contact between the sliding shoe and the track, which in turn affects the dynamic response of the track. Therefore, the rocket sled and the track are interacting systems, and it is difficult to consider the interaction between the two by modeling the track as a rigid body. In addition, when the sliding shoe hits the track at a specific frequency, the wavelength of the elastic wave in the track is equal to the distance between the two impacts of the sliding shoe. If the impact point of the slider is at the peak of the elastic wave that has been excited, the amplitude of the elastic wave will be strengthened, thus causing the track to resonate. Therefore, if the track is modeled as a rigid body, it is difficult to predict the track resonance.

[0055] Furthermore, the establishment of a dynamic model of shoe-rail interaction can realize the rigid-flexible coupling between the shoe and the rail, that is, the mutual influence of the dynamic response of the shoe and the dynamic response of the rail. Specifically, when the rail is deformed and vibrated by the force of the shoe, the contact position and speed between the shoe and the rail change, thereby affecting the dynamic response of the shoe; the change in the dynamic response of the shoe affects the subsequent contact with the rail, thereby affecting the dynamic response of the rail.

[0056] Furthermore, the sliding point node is set to achieve the above-mentioned shoe-rail interaction. Specifically, the resultant force and torque formed by the normal contact force and tangential contact force on the sliding point can be accurately transmitted to the reference line of the finite volume beam, thereby causing the flexible track model to produce a dynamic response under collision and friction excitation. When the flexible track model vibrates, the position, direction, velocity and angular velocity of each rail node changes, thereby changing the position and direction of the reference line of the finite volume beam. Therefore, the position and direction of the sliding point node change accordingly, and the potential contact point rigidly connected to it also changes position, thereby affecting the subsequent contact between the sliding shoe and the track.

[0057] Furthermore, the engine thrust setting is to simulate the rocket sled accelerating along a highly straight track under the propulsion of the solid rocket engine; in addition, the thrust oscillation caused by the combustion instability of the solid rocket engine can be simulated, and this thrust oscillation will cause the rocket sled to be subjected to nonlinear exciting forces. The aerodynamic drag setting is to simulate the aerodynamic drag actually encountered by the rocket sled during its movement. The modeling of the mass time-varying propellant is to simulate the continuous and significant mass reduction of the rocket sled caused by the consumption of propellant in the engine during the acceleration of the rocket sled. This time-varying mass and moment of inertia may produce nonlinear inertial forces or moments of inertia in the rocket sled.

[0058] It can be understood that the beneficial effects of the second aspect mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0059] In summary, the present invention can achieve rapid prediction of the dynamic response of the flexible rocket sled during the entire process of acceleration to supersonic speed along a kilometer-level flexible track, and verify the accuracy of the simulation method through rocket sled test data.

[0060] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 Flowchart of multi-body dynamics modeling and calculation method for high-speed rocket sled-track system;

[0062] Figure 2 This is the dynamic model diagram of the flexible rocket sled;

[0063] Figure 3 It is the diagram of the flexible track dynamics model;

[0064] Figure 4 Schematic diagram of potential contact points between the skid and the track;

[0065] Figure 5 The figure is a schematic diagram of the simulation and test values ​​of the rocket sled's heading displacement and heading velocity;

[0066] Figure 6 Schematic diagram of the simulation and test values ​​of the vertical acceleration and its root mean square of the front slide of the rocket sled, where (a) is within 1000 Hz; (b) is within 800 Hz; (c) is within 600 Hz; (d) is within 400 Hz; (e) is within 200 Hz;

[0067] Figure 7 A schematic diagram of a computer device provided by an embodiment of the present invention;

[0068] Figure 8 The block diagram of a chip provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0069] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0070] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0071] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0072] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0073] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0074] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0075] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0076] Aiming at the problem of calculation accuracy of the existing multi-body dynamics simulation method of high-speed rocket sled-track system, the present invention provides a multi-body dynamics calculation method of high-speed rocket sled-track system. Firstly, a flexible rocket sled dynamics model is established, and the model is verified by a rocket sled modal test; secondly, a flexible track dynamics model is established, and the model is verified by a track modal test; on the basis of the first two models, a shoe-track interaction dynamics model is established; then, on the basis of the first three models, engine thrust, aerodynamic drag, and mass time-varying propellant models are respectively established, and on this basis, a rocket sled-track system multi-body dynamics model is established; finally, a numerical method is used to calculate and solve the rocket sled-track system multi-body dynamics model to obtain the dynamic response of the rocket sled.

[0077] See also Figure 1 The present invention provides a multi-body dynamics calculation method for a high-speed rocket sled-track system, comprising the following steps:

[0078] S1. Establish a dynamic model of a flexible rocket sled and verify the dynamic model of the flexible rocket sled through a rocket sled modal test;

[0079] S101. Establish nodes corresponding to each substructure according to the specific rocket sled structure and parameters;

[0080] The flexible rocket sled dynamic model includes 1 fairing node, 1 equipment node, 5 cabin nodes, 1 accessory node, 1 nozzle node, 3 propellant nodes, and 3 skid nodes.

[0081] S102, according to the connection relationship between the substructures, use finite volume beam elements, multi-degree-of-freedom spring-damper elements and various sub-elements to connect the nodes;

[0082] See also Figure 2The flexible rocket sled dynamic model contains 6 cabin beam units and 3 four-dimensional viscoelastic (spring-damper) units. In the four-dimensional viscoelastic unit, the viscoelastic constitutive law including stiffness and damping matrices is used to connect the cabin and the skid nodes. The four dimensions include the translational degrees of freedom in three directions and the rotational degrees of freedom in the rolling direction. Since the propellant is surrounded by a cabin with greater stiffness, the propellant node is fixedly connected to the corresponding cabin node. The equipment node is located between the fairing node and the cabin node No. 1 and is fixedly connected to the cabin node No. 1. Similarly, the accessory node located between the nozzle node and the cabin node No. 5 is fixedly connected to the cabin node No. 5.

[0083] For the finite volume beam element, it contains finite influence regions at the two end nodes. The evaluation points are located at the boundaries between these regions. At each evaluation point of the finite volume beam element, a linear viscoelastic constitutive law is used to describe the relationship between the generalized internal forces and the generalized beam strains and their time derivatives, which is written as:

[0084]

[0085] Among them, F x is the axial force, F y and F z is the tangential force, M x is the torsional moment, M y and M z is the bending moment, ε x is the axial strain, γ y and γ z is the shear strain, κ x is the torsional curvature, κ y and κ z is the bending curvature. The superscript “·” indicates the time derivative of the physical quantity, K is the stiffness matrix of the evaluation point, P C is the proportional damping factor.

[0086] S103, performing characteristic analysis on the rocket sled dynamics model established in step S101 and step S102, obtaining the first three order calculated modal parameters, and verifying them according to the first three order experimental modal parameters obtained from the rocket sled modal test.

[0087] The results show that the first three calculated natural frequencies are 42.191Hz, 109.537Hz, and 204.072Hz, respectively, and the first three experimental natural frequencies are 43.156Hz, 105.113Hz, and 194.785Hz, respectively. The maximum error between calculation and experiment is 4.77%, which is considered acceptable, proving the accuracy of the rocket sled dynamics model.

[0088] S2. Establish a flexible track dynamics model and verify the flexible track dynamics model through track modal tests;

[0089] S201, establish a flexible track cycle calculation dynamics model;

[0090] When the rocket sled completes its movement on the specified track length, its final state is used as the initial condition for the next cycle until the rocket sled reaches its maximum speed; after multiple numerical experiments, the optimal track length for each cycle was determined to be 110 meters; in each cycle, the rocket sled moves from a track position of 10 meters to a track position of 100 meters.

[0091] S202, establishing nodes corresponding to each substructure of the flexible track in each cycle according to the specific track structure and parameters;

[0092] In the flexible track dynamic model, the flexible track in each cycle is composed of 110 track segments connected together, including 441 track nodes, 111 pillow nodes, and 111 ground nodes.

[0093] S203, according to the connection relationship between the track substructures in each cycle, use finite volume beam elements, multi-degree-of-freedom spring-damper elements and various sub-elements to connect the nodes;

[0094] See also Figure 3 The flexible track dynamics model adopts a discrete double-layer structure; the six degrees of freedom of all ground nodes are fixed; each track segment contains two supporting track nodes and three equidistant intermediate track nodes. Adjacent track segments are connected by a common supporting track node; each track node is connected by a finite volume beam element; the 6D viscoelastic element connects the track and pillow nodes, as well as the pillow nodes and ground nodes; unlike the four-dimensional viscoelastic element in the rocket sled model, the six-dimensional viscoelastic element also restricts the rotational degrees of freedom in the yaw and pitch directions.

[0095] S204, performing characteristic analysis on the flexible track dynamics model established in step S202 and step S203, obtaining calculated modal parameters, and verifying them according to the test modal parameters obtained from the track modal test;

[0096] The results show that the first four calculated natural frequencies are 425.2Hz, 430.8Hz, 440.2Hz, 453.4Hz, and the first four experimental natural frequencies are 423.9Hz, 427.7Hz, 432.3Hz, 436.1Hz. The maximum error between calculation and experiment is 3.97%, which is considered acceptable, proving the accuracy of the flexible track dynamic model.

[0097] S205. Calculate the power spectrum density of the measured short-distance track irregularity data, reconstruct the long-distance track irregularity through randomized phase, and apply it to the track model.

[0098] The power spectral density of the measured short-distance vertical and lateral track irregularity data is calculated and converted from a single-sided spectrum to a double-sided spectrum to determine the amplitude of the reconstructed track irregularity spectrum. The phase of the spectrum is randomized and uniformly distributed in the interval [0, 2π]. Finally, the track irregularity spectrum in the frequency domain is subjected to an inverse fast Fourier transform to reconstruct the 3000-meter-long vertical and lateral track irregularities and apply them to the track model.

[0099] S3, establish the dynamic model of shoe-rail interaction;

[0100] S301. Establish one "sliding point" node on each side of the front and rear of each shoe. These sliding point nodes have no mass and moment of inertia, and are used to describe the contact force between the sliding shoe and the track; the movement of the sliding point node in the heading is consistent with the corresponding sliding shoe, and is kept on the track axis through the "beam-sliding point" unit; the "beam-sliding point" unit restricts the sliding point node from sliding along a series of finite volume beams, and at the same time transmits the contact force between the track beam and the sliding point node at each contact point;

[0101] S302, defining potential contact points according to the contact surface shape of each sliding shoe, the contact points on the sliding shoe are fixedly connected to the sliding shoe nodes, and the contact points on each side of the sliding shoe on the track are fixedly connected to the corresponding sliding points;

[0102] See also Figure 4 , point A P Solstice J P is a potential contact point on the slider, with the slider node O P Connect. Point A D Solstice J D is the potential contact point on each side of the slide shoe on the track, and the corresponding sliding point O D Solid connection.

[0103] S303. According to the relative displacement and relative velocity relationship between each contact point pair, in combination with the Flores contact model, a normal contact force (collision) model and a tangential contact force (friction) model between each contact point pair are established.

[0104] S4. Establish engine thrust, aerodynamic drag, and mass time-varying propellant models respectively, and establish a multi-body dynamic model of the rocket sled-track system by combining the flexible rocket sled dynamic model obtained in step S1, the flexible track dynamic model obtained in step S2, and the shoe-track interaction dynamic model obtained in step S3. Obtain the dynamic response of the rocket sled by numerically solving the multi-body dynamic model of the rocket sled-track system.

[0105] S401, establishing an engine thrust model;

[0106] According to the factory thrust curve of the engine, the thrust time history curve is applied to the nozzle node in the positive direction of the heading;

[0107] S402, establishing an aerodynamic drag model;

[0108] The aerodynamic drag of each rocket sled node is calculated using computational fluid dynamics. The equations involved are three-dimensional steady compressible Navier-Stokes equations. In order to mitigate the nonphysical dissipative effects, the Roe flux difference scheme is used to discretize the inviscid flux, and the entropy method is used to correct the nonphysical solution. The spatial discretization adopts the second-order upwind scheme, and the turbulence is treated by the two-equation k-ω shear stress transfer model. Due to the small skid-track gap, the angle of attack and sideslip angle of the rocket sled are not considered. Some typical speeds are selected, and the steady aerodynamic drag of the rocket sled nodes at each typical speed is calculated, and the aerodynamic drag at all speeds is obtained by piecewise interpolation. During the multibody dynamics calculation process, the heading velocity of each rocket sled node can be determined at each time step, so that the corresponding aerodynamic drag value can be automatically retrieved. The direction of the aerodynamic drag of each node is along the negative heading direction.

[0109] Among them, the typical speeds selected are Mach numbers Ma = 0.6, 0.8, 1.2, 1.4, 1.6, 1.8, 2.0, and 3.0. The steady aerodynamic drag of the rocket sled nodes at each typical speed is calculated, and the aerodynamic drag at speeds of 0 to 3 Mach is obtained by piecewise interpolation.

[0110] S403, establish a mass time-varying propellant model;

[0111] According to the structural parameters of solid rocket propellant, the time-varying relationship between the mass and moment of inertia of each propellant node is solved and assigned to each propellant node.

[0112] S404, based on the flexible rocket sled dynamics model, flexible track dynamics model, and shoe-track interaction dynamics model established in step S1, step S2, and step S3, respectively, and the engine thrust model, aerodynamic drag model, and mass time-varying propellant model established in step S401, step S402, and step S403, respectively, a multi-body dynamics model of the rocket sled-track system is established;

[0113] S405. Solve the differential-algebraic equations corresponding to the multi-body dynamics model of the rocket sled-track system.

[0114] The time step is 10 -4 The computational resources are a computer with 8GB memory and a single core.

[0115] First, solve the initial derivatives of the system of equations;

[0116] In the first solution step, the Crank-Nicolson single-step integration method is used to start the calculation program;

[0117] In the subsequent solution steps, the double-step backward difference method is used to improve the calculation accuracy.

[0118] In yet another embodiment of the present invention, a high-speed rocket sled-track system multi-body dynamics calculation system is provided, which can be used to implement the above-mentioned high-speed rocket sled-track system multi-body dynamics calculation method. Specifically, the high-speed rocket sled-track system multi-body dynamics calculation system includes a rocket sled module, a track module, a shoe rail module and an output module.

[0119] Among them, the rocket sled module establishes a flexible rocket sled dynamic model and verifies the flexible rocket sled dynamic model through rocket sled modal tests;

[0120] Track module, establishes a flexible track dynamic model and verifies the flexible track dynamic model through track modal tests;

[0121] Shoe-rail module, to establish the shoe-rail interaction dynamics model;

[0122] The output module establishes engine thrust, aerodynamic drag, and mass time-varying propellant models respectively, and combines the obtained flexible rocket sled dynamics model, flexible track dynamics model, and shoe-track interaction dynamics model to establish a multi-body dynamics model of the rocket sled-track system. The dynamic response of the rocket sled is obtained by numerically solving the multi-body dynamics model of the rocket sled-track system.

[0123] In another embodiment of the present invention, a terminal device is provided, the terminal device includes a processor and a memory, the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions to implement corresponding method processes or corresponding functions; the processor described in the embodiment of the present invention can be used for the operation of the high-speed rocket sled-track system multi-body dynamics calculation method, including:

[0124] A flexible rocket sled dynamics model is established, and the flexible rocket sled dynamics model is verified through rocket sled modal tests; a flexible track dynamics model is established, and the flexible track dynamics model is verified through track modal tests; a shoe-track interaction dynamics model is established; engine thrust, aerodynamic drag, and mass time-varying propellant models are established respectively, and a multi-body dynamics model of the rocket sled-track system is established by combining the flexible rocket sled dynamics model, the flexible track dynamics model, and the shoe-track interaction dynamics model. The dynamic response of the rocket sled is obtained by numerically solving the multi-body dynamics model of the rocket sled-track system.

[0125] In another embodiment of the present invention, the present invention further provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a terminal device for storing programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and the extended storage medium supported by the terminal device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory, or a non-volatile memory (Non-Volatile Memory), such as at least one disk memory.

[0126] The processor may load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the high-speed rocket sled-track system multi-body dynamics calculation method in the above embodiment; the processor may load and execute the following steps of one or more instructions in the computer-readable storage medium:

[0127] A flexible rocket sled dynamics model is established, and the flexible rocket sled dynamics model is verified through rocket sled modal tests; a flexible track dynamics model is established, and the flexible track dynamics model is verified through track modal tests; a shoe-track interaction dynamics model is established; engine thrust, aerodynamic drag, and mass time-varying propellant models are established respectively, and a multi-body dynamics model of the rocket sled-track system is established by combining the flexible rocket sled dynamics model, the flexible track dynamics model, and the shoe-track interaction dynamics model. The dynamic response of the rocket sled is obtained by numerically solving the multi-body dynamics model of the rocket sled-track system.

[0128] See also Figure 7 , the terminal device is a computer device. The computer device 60 of this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the computer program 63 is executed by the processor 61, the high-speed rocket sled-track system multi-body dynamics calculation method in the embodiment is implemented. To avoid repetition, it is not described one by one here. Alternatively, when the computer program 63 is executed by the processor 61, the functions of each model / unit in the high-speed rocket sled-track system multi-body dynamics calculation system in the embodiment are implemented. To avoid repetition, it is not described one by one here.

[0129] The computer device 60 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will appreciate that Figure 7 This is only an example of the computer device 60 and does not constitute a limitation of the computer device 60. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0130] The processor 61 may be a central processing unit (CPU), or other general-purpose processors, central processing units, graphics processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, data processing logic based on quantum computing, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0131] The memory 62 may be an internal storage unit of the computer device 60, such as a hard disk or memory of the computer device 60. The memory 62 may also be an external storage device of the computer device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the computer device 60.

[0132] Furthermore, the memory 62 may include both an internal storage unit of the computer device 60 and an external storage device. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 may also be used to temporarily store data that has been output or is to be output.

[0133] Any reference to memory, database or other media used in the embodiments provided in the present application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0134] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0135] See also Figure 8 The terminal device 600 is an electronic device, and the electronic device is in the form of a general computing device. The components of the electronic device may include but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including the storage unit 620 and the processing unit 610), a display unit 640, etc.

[0136] The storage unit stores program codes, which can be executed by the processing unit 610, so that the processing unit 610 performs the steps according to various exemplary embodiments of the present invention described in the above method section of this specification. For example, the processing unit 610 can perform the following steps: Figure 1 Follow the steps shown in .

[0137] The storage unit 620 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 6201 and / or a cache memory unit 6202 , and may further include a read-only memory unit (ROM) 6203 .

[0138] The storage unit 620 may also include a program / utility 6204 having a set (at least one) of program modules 6205, such program modules 6205 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0139] Bus 630 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0140] The electronic device 600 may also communicate with one or more external devices 700 (e.g., keyboards, pointing devices, Bluetooth devices, etc.), may also communicate with one or more devices that enable a user to interact with the electronic device 600, and / or communicate with any device that enables the electronic device 600 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed via an input / output (I / O) interface 650. Furthermore, the electronic device 600 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 660. The network adapter 660 may communicate with other modules of the electronic device 600 via a bus 630. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms, etc.

[0141] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0142] Finally, after 29 simulation cycles, the simulation was completed, which took a total of 1.7 hours, with an average time of about 0.1 seconds per time step. The total time and average time were within an acceptable range, proving the efficiency of this method.

[0143] Next, the simulation results are compared with the test values ​​of the rocket sled. First, the simulation values ​​and test values ​​of the heading displacement and heading velocity of the rocket sled are compared, such as Figure 5 shown.

[0144] The final heading distance of the test rocket sled was 2491 meters, while the simulation rocket sled reached 2531 meters, with an error of 1.61%. The maximum heading speed in the test was 915 meters per second, while in the simulation it was 931 meters per second, with an error of 1.75%. These errors are considered acceptable and verify the accuracy of the method in estimating the heading motion of the rocket sled;

[0145] Secondly, the simulation and test values ​​of the vertical acceleration and its root mean square of the front shoe of the rocket sled were compared. The simulation and test data were low-pass filtered with the same cutoff frequency, which was 1000 Hz, 800 Hz, 600 Hz, 400 Hz, and 200 Hz, respectively, to facilitate the comparison of the simulation and test shoe accelerations in different frequency ranges. The root mean square value was calculated based on the acceleration data every 0.2 seconds to facilitate statistical comparison of the simulation and test values ​​in different time ranges.

[0146] The results show that the simulation value and the test value are highly consistent at different time scales and frequency scales, which proves the accuracy of the method of the present invention.

[0147] In summary, the multi-body dynamics calculation method and system of a high-speed rocket sled-track system of the present invention can predict the dynamic response of the entire process of the rocket sled accelerating along the track; the method of the present invention uses a cyclic calculation model, which greatly improves the calculation efficiency. By comparing the heading position and speed of the rocket sled in simulation and experiment, the accuracy of the method in predicting the heading motion of the rocket sled is verified, and the maximum error is 1.75%. The root mean square value of the vertical acceleration of the front skid in simulation and experiment is compared. The results show that at different cutoff frequencies (1,000Hz, 800Hz, 600Hz, 400Hz, 200Hz), the simulation value and the test value have a high consistency, which proves the accuracy of the method of the present invention.

[0148] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0149] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0150] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the present invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0151] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0152] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0153] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0154] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0155] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0156] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0157] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0158] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A multi-body dynamics calculation method for a high-speed rocket sled-track system, characterized in that: The following steps are involved: The dynamic model of the flexible rocket sled is established and verified through the rocket sled modal test; Establish a flexible track dynamic model and verify it through track modal tests; Establish the dynamic model of shoe-rail interaction; The engine thrust, aerodynamic drag and mass time-varying propellant models are established respectively. The multi-body dynamic model of the rocket sled-track system is established by combining the obtained flexible rocket sled dynamic model, flexible track dynamic model and shoe-track interaction dynamic model. The dynamic response of the rocket sled is obtained by numerically solving the multi-body dynamic model of the rocket sled-track system.

2. The high-speed rocket sled-track system multi-body dynamics calculation method according to claim 1 is characterized in that: The dynamic model of the flexible rocket sled is established as follows: According to the specific rocket sled structure and parameters, establish the nodes corresponding to each substructure; According to the connection relationship between each substructure, finite volume beam elements, multi-degree-of-freedom spring-damper elements and various sub-elements are used to connect each node to obtain the dynamic model of the rocket sled; The established rocket sled dynamic model is characterized by analysis, and the calculated modal parameters are obtained, which are then verified based on the experimental modal parameters obtained from the rocket sled modal test.

3. The high-speed rocket sled-track system multi-body dynamics calculation method according to claim 2 is characterized in that: The finite volume beam element contains a limited influence region at the two end nodes; at each evaluation point of the finite volume beam element, a linear viscoelastic constitutive law is used to describe the relationship between the generalized internal forces and the generalized beam strains and their time derivatives, specifically: Among them, F x is the axial force, F y and F z is the tangential force, M x is the torsional moment, M y and M z is the bending moment, ε x is the axial strain, γ y and γ z is the shear strain, κ x is the torsional curvature, κ y and κ z is the bending curvature; the superscript "·" indicates the time derivative of the physical quantity, K is the stiffness matrix of the evaluation point, P C is the proportional damping factor.

4. The multi-body dynamics calculation method of a high-speed rocket sled-track system according to claim 1, characterized in that: The flexible track dynamics model is established as follows: Establish a computational dynamics model for flexible track cycles; According to the specific track structure and parameters, the nodes corresponding to each substructure of the flexible track in each cycle are established; According to the connection relationship between the substructures of the track in each cycle, finite volume beam elements, multi-degree-of-freedom spring-damper elements and various sub-elements are used to connect the nodes; Conduct characteristic analysis on the established flexible track dynamics model to obtain the calculated modal parameters, and verify it based on the experimental modal parameters obtained from the track modal test; The power spectral density of the measured short-distance track irregularity data is calculated, and the long-distance track irregularity is reconstructed through randomized phase and applied to the flexible track dynamics model.

5. The high-speed rocket sled-track system multi-body dynamics calculation method according to claim 4 is characterized in that: The flexible track dynamic model adopts a discrete double-layer structure; the six degrees of freedom of all ground nodes are fixed; each track segment contains two supporting track nodes and three equidistant intermediate track nodes; adjacent track segments are connected by a common supporting track node; each track node is connected by a finite volume beam element; 6D viscoelastic elements connect the track and pillow nodes, as well as the pillow nodes and ground nodes.

6. The high-speed rocket sled-track system multi-body dynamics calculation method according to claim 1, characterized in that: The specific model of shoe-rail interaction dynamics is established as follows: One sliding point node is established on the front and rear sides of each sliding shoe; According to the contact surface shape of each sliding shoe, each potential contact point is defined respectively, the contact point on the sliding shoe is fixedly connected to the sliding shoe node, and the contact point on each side of the sliding shoe on the track is fixedly connected to the corresponding sliding point; According to the relationship between the relative displacement and relative velocity between each contact point pair and combined with the Flores contact model, the normal contact force model and the tangential contact force model between each contact point pair are established.

7. The high-speed rocket sled-track system multi-body dynamics calculation method according to claim 6, characterized in that: The sliding point node has no mass and moment of inertia, and is used to describe the contact force between the sliding shoe and the track. The sliding point node's motion in the heading direction is consistent with the corresponding sliding shoe, and is kept on the track axis through the beam-sliding point unit. The beam-slider element constrains the slide node to slide along a series of finite volume beams while transferring the contact force between the track beam and the slide node at each contact point.

8. The high-speed rocket sled-track system multi-body dynamics calculation method according to claim 1, characterized in that: The engine thrust, aerodynamic drag, and mass time-varying propellant models are established as follows: Establish an engine thrust model; according to the factory thrust curve of the engine, apply the thrust time history curve to the nozzle node, along the positive direction of the heading; Establish an aerodynamic drag model; use computational fluid dynamics methods to calculate the aerodynamic drag of each rocket sled node; A mass time-varying propellant model is established. According to the structural parameters of solid rocket propellant, the relationship between the mass and moment of inertia of each propellant node and time is solved and assigned to each propellant node. A multi-body dynamics model of the rocket sled-track system is established based on the flexible rocket sled dynamics model, flexible track dynamics model, shoe-track interaction dynamics model, and the engine thrust model, aerodynamic drag model, and mass time-varying propellant model. The differential-algebraic equations corresponding to the multi-body dynamics model of the rocket sled-track system are solved to obtain the dynamic response of the rocket sled during the entire acceleration process along the track.

9. The high-speed rocket sled-track system multi-body dynamics calculation method according to claim 8, characterized in that: The differential-algebraic equations corresponding to solving the multi-body dynamics model of the rocket sled-track system are as follows: First, the initial derivatives of the system of equations are solved; in the first solution step, the Crank-Nicolson single-step integration method is used to start the calculation program; In the subsequent solution steps, the double-step backward difference method is used.

10. A high-speed rocket sled-track system multi-body dynamics calculation system, characterized in that: include: Rocket sled module, establishes a flexible rocket sled dynamic model, and verifies the flexible rocket sled dynamic model through rocket sled modal tests; Track module, establishes a flexible track dynamic model and verifies the flexible track dynamic model through track modal tests; Shoe-rail module, to establish the shoe-rail interaction dynamics model; The output module establishes engine thrust, aerodynamic drag, and mass time-varying propellant models respectively, and combines the obtained flexible rocket sled dynamics model, flexible track dynamics model, and shoe-track interaction dynamics model to establish a multi-body dynamics model of the rocket sled-track system. The dynamic response of the rocket sled is obtained by numerically solving the multi-body dynamics model of the rocket sled-track system.

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