A test rig scale-down analysis method based on similarity theory and related device

Abstract

The application discloses a test frame scale-down analysis method based on similarity theory and related devices, and belongs to the technical field of test frame scale-down analysis; a test frame scale-down three-dimensional model based on similarity theory is established according to a scale-down coefficient; a static finite element analysis model is established through the test frame scale-down three-dimensional model based on similarity theory; based on a stress-strain scale-down principle, static characteristic analysis is performed on the test frame scale-down three-dimensional model through the static finite element analysis model; finally, finite element analysis calculation of inherent frequency is performed on the test frame scale-down three-dimensional model, and dynamic characteristic analysis is performed on the extracted 1-6 order modes. The application proposes a scale-down method of geometric sizes of the test frame under different load conditions, and analyzes static characteristics and dynamic characteristic simulation analysis of key structural parts under different loads and size states based on Workbench, so that the reliability of scale-down experiments is improved, the design cycle is reduced, and technical support of scale-down theory is provided for scale-down design of large-tonnage test frames.

Description

Technical Field

[0001] This invention belongs to the field of test frame scaling analysis technology, and relates to a test frame scaling analysis method and related apparatus based on similarity theory. Background Technology

[0002] The test rig is the "core device" of the test stand, used to test aerospace engines in order to obtain thrust data and ensure flight safety. Currently, the design of test rigs for liquid aerospace engines is insufficient to meet the development and testing requirements of high-thrust liquid rocket engines, hindering the development and testing of large-tonnage liquid rocket engines. This means that aerospace technology is constrained, and aerospace strategy is passive.

[0003] To shorten the design cycle, reduce R&D costs, and verify the effectiveness of design schemes, it is necessary to design a scaled-down model experimental platform based on the principle of similarity to verify the effectiveness of the design schemes. Existing scaled-down test bench experiments rely on personal experience in selecting various scaling factors, often only considering "simple and intuitive" factors, lacking quantitative and error analysis. Scaled-down experiments lack theoretical basis, resulting in unreliable experimental results and making it difficult to provide guidance for the design of large-tonnage test benches. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems in the prior art where the selection of various scaling factors in scaled-down test bench experiments relies on personal experience, lacks quantitative and error analysis, lacks theoretical basis, and has low reliability of experimental results. The invention provides a scaled-down test bench analysis method and related device based on similarity theory.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] In a first aspect, the present invention provides a scaled-down analysis method for test frames based on similarity theory, comprising the following steps:

[0007] A scaled-down three-dimensional model of the test frame based on similarity theory was established according to the scaling factor.

[0008] A static finite element analysis model was established using a scaled-down three-dimensional model of a test frame based on similarity theory.

[0009] Based on the stress-strain scaling principle, static characteristic analysis of the scaled-down three-dimensional model of the test frame is carried out through static finite element analysis model.

[0010] Finite element analysis was performed on the natural frequencies of the scaled-down three-dimensional model of the test frame, and the first to sixth order modes were extracted for dynamic characteristic analysis.

[0011] Secondly, the present invention provides a scaled-down test frame analysis system based on similarity theory, comprising:

[0012] The 3D model building module is used to build a scaled-down 3D model of the test frame based on similarity theory according to the scaling factor.

[0013] The finite element analysis module is used to establish a static finite element analysis model using a scaled-down 3D model of a test bench based on similarity theory.

[0014] The static characteristic analysis module is used to perform static characteristic analysis on the scaled-down three-dimensional model of the test frame based on the stress-strain scaling principle and through a static finite element analysis model.

[0015] The dynamic characteristic analysis module is used to perform finite element analysis calculations of the natural frequencies of the scaled-down three-dimensional model of the test frame, and to extract the 1st to 6th order modes for dynamic characteristic analysis.

[0016] Thirdly, the present invention provides a computer device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described above.

[0017] Fourthly, the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method described above.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This invention discloses a scaled-down analysis method and related apparatus for test frames based on similarity theory. Addressing the challenge of uncertain correspondence between loads, constraints, and geometric dimensions, this invention establishes similarity criteria for stress and strain distribution, proposes a scaled-down method for the geometric dimensions of the test frame under different load conditions, and then establishes a scaled-down three-dimensional model of the test frame based on different scaled-down coefficients. Furthermore, it analyzes the static and dynamic characteristics of key structural components under different loads and dimensions using Workbench simulation analysis, thereby improving the reliability of scaled-down experiments, reducing the design cycle, and providing technical support for the scaled-down design of large-tonnage test frames. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart of the method of the present invention;

[0022] Figure 2 This is a schematic diagram of the system of the present invention;

[0023] Figure 3 This is a flowchart of the experimental method in an embodiment of the present invention;

[0024] Figure 4 This is a model diagram of the main structure of the test frame according to an embodiment of the present invention;

[0025] Figure 5 This is a scaled-down model diagram of the test frame according to an embodiment of the present invention;

[0026] Figure 6 This is a diagram showing the variation of strain in the horizontal direction with load according to an embodiment of the present invention;

[0027] Figure 7 This is a diagram showing the variation of strain in the vertical direction with load according to an embodiment of the present invention;

[0028] Figure 8 This is a graph showing how the deviation varies with load in an embodiment of the present invention;

[0029] Figure 9 This is a schematic diagram of the computer device structure of the present invention.

[0030] Wherein: 1-reduced front inclined column; 2-reduced rear inclined column. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0033] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0034] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0035] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0036] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0037] The present invention will now be described in further detail with reference to the accompanying drawings:

[0038] See Figure 1 This invention provides a method for scaled-down analysis of test frames based on similarity theory, comprising the following steps:

[0039] S1. Establish a scaled-down three-dimensional model of the test frame based on similarity theory according to the scaling factor; the applied load should correspond to the scaling factor.

[0040] S2, a static finite element analysis model is established using a scaled-down three-dimensional model of the test frame based on similarity theory;

[0041] S3, based on the stress-strain scaling principle, static characteristic analysis of the scaled three-dimensional model of the test frame is performed through a static finite element analysis model;

[0042] S4. Finite element analysis was performed on the natural frequencies of the scaled-down three-dimensional model of the test frame, and the 1st to 6th order modes were extracted for dynamic characteristic analysis.

[0043] In one feasible embodiment of the present invention, obtaining the scaling factor includes the following steps:

[0044] a. Calculate the principal stresses on the cross-section of the test frame support when the tensile load is W;

[0045] b. Calculate the scaling factor λ of the tensile load according to the definition of the scaling factor. w The scaling factor λ of the axis length h ;

[0046] c. The scaling factor λ of principal stress and tensile load w The scaling factor λ of the axis length h Determine the stress scaling factor and the strain scaling factor;

[0047] d. Based on the derivation results of the stress scaling factor and strain scaling factor, determine the relationship between the scaled-down dimensions of the test frame and the applied load for subsequent static analysis;

[0048] Based on the derived stress and strain distribution similarity relationships, scaled-down models with different size similarity coefficients are designed. From these size scaling coefficients, load scaling coefficients can be derived, thus determining the corresponding applied load values. This allows for the calculation of the load values ​​to be applied under different size scaling coefficients to facilitate mechanical response analysis. Regarding materials, the scaled-down model uses the same materials as the prototype, therefore the similarity coefficient of the material parameters satisfies λ. E =1, λ ρ =1.

[0049] In a feasible embodiment of the present invention, the calculation of the principal stress when the tensile load on the cross section of the test frame support is W specifically includes:

[0050] Taking any cross-section of the test frame support as a prototype, with a cross-sectional area of ​​A, an axial length of h, an elastic modulus of E, a material density of ρ, and a Poisson's ratio of v, and a tensile load of W applied to the cross-section at a certain moment, the formula for calculating the principal stress σ is as follows:

[0051] σ=W / A (1)

[0052] The relationship between stress σ and strain ε under uniaxial stress is as follows:

[0053] σ=Eε (2)

[0054] The scaling factor λ for the tensile load is calculated according to the definition of the scaling factor. w The scaling factor λ of the axis length h The specific calculation formula is as follows:

[0055]

[0056]

[0057] Where W1 is the initial tensile load, W nThis is the scaled-down tensile load; h1 is the initial shaft length, h n It is the axis length after scaling.

[0058] In one feasible embodiment of the present invention, the scaling factor λ of the principal stress and tensile load is... w The scaling factor λ of the axis length h Determining the stress scaling factor and strain scaling factor specifically includes:

[0059]

[0060] Where A1 is the initial cross-sectional area, A n It is the reduced cross-sectional area; σ n σ1 is the stress of the cross section after scaling down; σ1 is the stress of the cross section before scaling down.

[0061] The area scaling factor λ A With axis length scaling factor λ h The relationship is:

[0062] λ A =λ h 2 (6)

[0063] Based on equations (5) and (6), the stress scaling factor λ is derived. σ for:

[0064]

[0065] Based on equations (2) and (7), the scaling factor λ of the strain is derived. ε for:

[0066] λ σ =λ ε (8)

[0067] In one feasible embodiment of the present invention, the step of establishing a static finite element analysis model by means of a scaled-down three-dimensional model of a test frame based on similarity theory specifically includes: importing the scaled-down three-dimensional model of the test frame based on similarity theory into Workbench, redefining the material properties of the scaled-down model, assigning the material properties to the components, and dividing the mesh accuracy based on a combination of calculation accuracy and calculation efficiency.

[0068] In practical applications, the quality of the mesh generation directly affects the accuracy of the finite element method (FEM) calculation results. A coarse mesh leads to inaccurate results, failing to accurately reflect the stress state of components; conversely, an overly fine mesh increases computation time and computational space usage by orders of magnitude, resulting in very low computational efficiency. Therefore, when generating the mesh, both computational accuracy and efficiency must be considered comprehensively.

[0069] Based on the scaling principle, determine the main loads, gravity, and support reactions of the supporting components that the scaled-down component will bear, apply the loads, and then solve the problem.

[0070] In one feasible embodiment of the present invention, the static characteristic analysis of the scaled-down three-dimensional model of the test frame based on the stress-strain scaling principle and the static finite element analysis model specifically includes: performing finite element analysis calculations on the test frame model with the applied load proportionally reduced according to different scaling factors based on the stress-strain scaling principle, and extracting stress cloud maps and strain cloud maps under each scaling factor to calculate the maximum stress and strain; then selecting new nodes according to the location to calculate the stress distribution, applying a proportionally reduced load, and then establishing a new scaled-down three-dimensional model of the test frame based on similarity theory according to the previous steps, and obtaining the stress through software analysis, and finally comparing the stress at corresponding positions of test frames with different scaling factors.

[0071] In a feasible embodiment of the present invention, the step of performing finite element analysis calculations on the natural frequencies of the scaled-down three-dimensional model of the test frame and extracting the 1st to 6th order modes for dynamic characteristic analysis specifically includes: considering whether the dynamic characteristics of the scaled-down model also have a high degree of similarity, performing similarity error analysis on the natural frequencies of the scaled-down model, and the calculation formula is as follows:

[0072] Model prediction frequency = Model frequency / Scale factor

[0073] Similarity error = (model prediction frequency - prototype frequency) / prototype frequency; similarity error analysis;

[0074] If the similarity error of each natural frequency is less than 1%, then the scaled-down models and the flexible connector models have high similarity in terms of dynamic characteristics.

[0075] See Figure 2 This invention discloses a scaled-down test frame analysis system based on similarity theory, comprising:

[0076] The 3D model building module is used to build a scaled-down 3D model of the test frame based on similarity theory according to the scaling factor.

[0077] The finite element analysis module is used to establish a static finite element analysis model using a scaled-down 3D model of a test bench based on similarity theory.

[0078] The static characteristic analysis module is used to perform static characteristic analysis on the scaled-down three-dimensional model of the test frame based on the stress-strain scaling principle and through a static finite element analysis model.

[0079] The dynamic characteristic analysis module is used to perform finite element analysis calculations of the natural frequencies of the scaled-down three-dimensional model of the test frame, and to extract the 1st to 6th order modes for dynamic characteristic analysis.

[0080] See Figure 9 This invention discloses a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described above.

[0081] This invention discloses a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method described above.

[0082] This invention also discloses a scaled-down validity verification system for a test frame. The experimental model of the scaled-down validity verification system is a test frame model, and the measuring equipment includes strain measurement equipment and modal measurement equipment. The scaled-down validity verification system provides two verification methods for the scaled-down test frame model: a strain measurement method and a modal measurement method.

[0083] The test frame model is a scaled-down test frame system. To facilitate manufacturing and experimental verification, the scaled-down test frame is usually no more than 2m in size.

[0084] The strain measurement equipment mainly includes an FPY-101 type jack, a USB8710 type strain / bridge input strain gauge, a static resistance strain gauge, a tearable ribbon cable, a soldering iron, an insulating tube, solder and rosin, and experimental fixtures.

[0085] The modal measurement device adopts the LMS modal analysis equipment. The entire analysis equipment performs modal measurement through hammer excitation and collects data through a portable dynamic information analyzer. It can measure the natural frequency with relatively high accuracy. The excitation method is the hammer excitation method.

[0086] In practical applications, the strain measurement method used is the static simulation loading resistance strain measurement method. Its basic principle is that when a resistance strain gauge deforms under load, the deformation is analyzed using a resistance strain gauge, and then the stress value at the measurement point is calculated based on the strain-stress relationship. The advantages of this method are convenient measurement, simple measuring equipment, and sufficient measurement accuracy. A jack is fixed using clamps to transfer force to the entire test frame. A pressure sensor is placed between the jack and the working surface to display the force magnitude. The midpoint of the inclined column, the main support component of the test frame, is selected as the measurement point for the static strain of the test frame. A metal strain sensor is placed there to detect the deformation of the test frame model under different loads. By comparing and analyzing the simulation calculation results of the scaled-down model with the actual experimental results, the correctness of the finite element simulation method mentioned above is verified.

[0087] In practical applications, the modal measurement method is based on the principle of modal analysis. In practical applications, when the structure is relatively light and small and the damping is not large, the hammer excitation method is commonly used, that is, the single-click vibration method. The excitation is generated by the LMS modal hammer striking the structure, the excitation signal is measured by the LMS three-phase sensor, and the corresponding modal signal is collected by the LMS dynamic signal analyzer.

[0088] Example:

[0089] This invention provides an embodiment of a test frame system (see...) Figure 4 The scaled-down model (see) Figure 5 This will be explained using an analytical experiment as an example, combined with... Figure 3 The design steps are as follows:

[0090] (1) See Figure 4 Based on the principle of test frame scaling in similarity theory, a scaled-down model with different size similarity coefficients is designed. The load scaling coefficient can be derived from the size scaling coefficient, thereby determining the corresponding value of the applied load. Simulation analysis and experimental verification are carried out using the scaled-down model of inclined column 1 as an example.

[0091] Table 1 Comparison of Scale-down Factor and Applied Load

[0092]

[0093] (2) Establishment of the static finite element analysis model;

[0094] The 3D model of the inclined column was imported into Workbench, and the material properties of the test frame were redefined, with cast iron material properties assigned to the components. The software's built-in Meshing module was used to mesh the model. For areas prone to stress concentration at the top and bottom transition zones of the inclined column, the mesh was refined. In actual operation, the test frame primarily bears the engine's gravity and propulsion pressure, as well as the support reactions of the supporting components. Therefore, the support reactions of the inclined column were constrained through boundary conditions. Load forces were then applied and solved based on load analysis at different scaling factors.

[0095] (3) Conduct static characteristic analysis of the scaled-down test frame model;

[0096] Based on the stress-strain scaling principle, finite element analysis was performed on proportionally scaled test frame models with corresponding loads applied at different scaling factors. The results are shown in Table 2. It can be seen that the maximum equivalent deformation and maximum equivalent stress are basically equal for different scaled models. Considering that stress concentration exists at the point of maximum stress, new nodes were selected to calculate the stress distribution. The specific node selection is as follows: Figure 4As shown in Table 3, a proportionally scaled load was applied, and the model was built following the same steps. The stresses obtained through software analysis are shown in Table 3. The data in the table show that the nodal stresses at the same node are basically the same for different scaled models, verifying that different scaled models have high similarity in static characteristics.

[0097] Table 2 Static Analysis Results of the Scaled-Down Model with Equal Proportioning Inclined Columns

[0098]

[0099] Table 3 shows the calculation results of the scaled-down model at the nodes.

[0100]

[0101] (4) Dynamic characteristics analysis of the scaled-down test frame model.

[0102] Considering the dynamic characteristics of the structure, finite element analysis was performed on the natural frequencies at the inclined columns. The calculation results are shown in Table 4.

[0103] Table 4. Calculation results of natural frequencies of the scaled-down model

[0104]

[0105] Considering the possibility that the dynamic characteristics of the scaled-down model also exhibit high similarity, a similarity error analysis is performed on the natural frequencies of the scaled-down model. The calculation formula is shown below:

[0106] Model prediction frequency = Model frequency / Scale factor Similarity error = (Model prediction frequency - Prototype frequency) / Prototype frequency

[0107] The corresponding similarity errors calculated according to the formula are shown in Table 5. The data in the table show that the similarity errors of each natural frequency are almost all within 1%, indicating that each scaled-down model and the oblique cylindrical model (prototype) have a high degree of similarity in terms of dynamic characteristics.

[0108] Table 5. Calculation results of similarity error for scaled-down models

[0109]

[0110]

[0111] (5) Design of scaled-down experimental system

[0112] A simplified version of the test frame model, reduced to one-twentieth the size of the original, was used for experimental verification. The experimental fabrication model is as follows: Figure 5 As shown, the original inclined column 1 is reduced to one-twentieth of its original size and then becomes the reduced inclined column 2.

[0113] The experimental equipment mainly includes FPY-101 type jacks, USB8710 type strain / bridge input strain gauges, static resistance strain gauges, tearable ribbon cables, soldering irons, insulating tubes, solder and rosin, experimental fixtures, and scaled-down physical models of test benches.

[0114] For modal measurement, the main analysis of the solid frequencies of the model is performed using the LMS modal analysis equipment. The entire analysis equipment performs modal measurements through hammer excitation and collects data through a portable dynamic information analyzer, which can measure relatively accurate natural frequencies.

[0115] (6) Strain Experiment Analysis

[0116] Considering that the installation of the four inclined columns cannot be completely identical, the strain of the four inclined columns was measured and the average value was used for analysis. The simulation results were then compared and analyzed with the experimental results, as shown in Table 6 and the comparative analysis results in Table 7.

[0117] Analysis shows that under different loads, the strain variation trend is the same as that of the simulation data, both exhibiting a linear proportional change. Furthermore, the deviations between experimental and simulation data under different loads are mostly within 10%, with an overall deviation within 20%. The relevant variation curves are shown below. Figure 6 , Figure 7 and Figure 8 As shown.

[0118] Table 6 Experimental Data

[0119]

[0120]

[0121] Table 7 Comparative Analysis Results

[0122]

[0123]

[0124] (7) Modal Experiment Analysis

[0125] Modal analysis may reveal cases where the mode shapes are essentially the same, but the frequencies differ slightly. This is due to the symmetry of the model. Errors in finite element analysis can cause slight differences between the two directions, resulting in identical mode shapes but slightly different frequencies. Therefore, when selecting simulation data, one of the closest data sets should be chosen. The experimentally obtained natural frequencies are compared with the simulation data, and the deviations are calculated as shown in Table 8.

[0126] In the experimental analysis of the natural frequency, the deviation between the experimental data and the simulation data was relatively small, with most deviations within 5% and the overall deviation within 10%. The experiment verified the correctness of the simulation.

[0127] Table 8 Simulation and Experimental Results of Natural Frequency

[0128]

[0129] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0130] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0131] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0132] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A scaled-down analysis method for test frames based on similarity theory, characterized in that, Includes the following steps: A scaled-down three-dimensional model of the test frame based on similarity theory was established according to the scaling factor. A static finite element analysis model was established using a scaled-down three-dimensional model of a test bench based on similarity theory. Based on the stress-strain scaling principle, a static characteristic analysis of the scaled-down three-dimensional model of the test frame is performed using a static finite element analysis model. Specifically, this includes: performing finite element analysis calculations on the test frame model with the applied load proportionally reduced for different scaling factors based on the stress-strain scaling principle, and extracting stress and strain cloud maps under each scaling factor to calculate the maximum stress and strain; then, selecting new nodes according to their locations to calculate the stress distribution, applying a proportionally reduced load, establishing a new scaled-down three-dimensional model of the test frame based on similarity theory, obtaining the stress, and finally comparing the stress at corresponding locations of different scaled-down test frames. Finite element analysis was performed on the natural frequencies of the scaled-down 3D model of the test frame, and the 1st to 6th order modes were extracted for dynamic characteristic analysis. Specifically, similarity error analysis was performed on the natural frequencies of the scaled-down model, and the calculation formula is as follows: Model prediction frequency = model frequency / scaling factor Similarity error = (model prediction frequency - prototype frequency) / prototype frequency; Similarity error analysis; If the similarity error of each natural frequency is less than 1%, then the scaled-down models and the flexible connector models have high similarity in terms of dynamic characteristics.

2. The test frame scaling analysis method based on similarity theory according to claim 1, characterized in that, Obtaining the scaling factor includes the following steps: Calculate the tensile load on the cross section of the test frame support. W The principal stress at that time; Calculate the scaling factor of the tensile load according to the definition of the scaling factor. λ w The scaling factor with respect to the axis length λ h ; Through the scaling factor of principal stress and tensile load λ w The scaling factor of the axis length λ h Determine the stress scaling factor and the strain scaling factor; Based on the derivation results of the stress scaling factor and strain scaling factor, the relationship between the scaling dimensions of the test frame and the applied load was determined.

3. The test frame scaling analysis method based on similarity theory according to claim 2, characterized in that, The tensile load on the cross section of the test frame support is calculated as follows: W The principal stresses at that time specifically include: Taking any cross-section of the test frame support as a prototype, its cross-sectional area is... A The axis length is h The elastic modulus of the support material is E The material density is ρ The material's Poisson's ratio is v The tensile load applied to the cross section at a certain moment is W Then the principal stress The calculation formula is as follows: (1) Stress under uniaxial stress state With strain The relationship is as follows: (2) The scaling factor for the tensile load is calculated according to the definition of the scaling factor. λ w The scaling factor with respect to the axis length λ h The specific calculation formula is as follows: (3) (4) in, W 1 is the initial tensile load. W n It is the tensile load after scaling. h 1 is the initial axis length. h n It is the axis length after scaling.

4. The test frame scaling analysis method based on similarity theory according to claim 3, characterized in that, The scaling factor through principal stress and tensile load λ w The scaling factor of the axis length λ h Determining the stress scaling factor and strain scaling factor specifically includes: (5) in, A 1 is the initial cross-sectional area. A n It is the reduced cross-sectional area; It is the stress in the section after scaling down; It is the stress in the cross section before scaling down; Area scaling factor λ A Reduction factor of axis length λ h The relationship is: (6) Based on equations (5) and (6), the stress scaling factor is derived. λ σ for: (7) Based on equations (2) and (7), the scaling factor of strain is derived. λ ε for: (8) in, λ σ is the stress scaling factor; λ ε is the scaling factor for strain.

5. The test frame scaling analysis method based on similarity theory according to claim 1, characterized in that, The process of establishing a static finite element analysis model using a scaled-down 3D model of the test frame based on similarity theory specifically includes: importing the scaled-down 3D model of the test frame based on similarity theory into Workbench, redefining the material properties of the scaled-down model and assigning the material properties to the components, dividing the mesh accuracy based on a combination of calculation accuracy and calculation efficiency, determining the main loads, gravity and support reaction forces of the scaled-down components according to the scaling principle, applying the load and performing the solution.

6. A scaled-down test frame analysis system based on similarity theory, characterized in that, A scaled-down test frame analysis method based on similarity theory, according to any one of claims 1 to 5, includes: The 3D model building module is used to build a scaled-down 3D model of the test frame based on similarity theory according to the scaling factor. The finite element analysis module is used to establish a static finite element analysis model using a scaled-down 3D model of a test bench based on similarity theory. The static characteristic analysis module is used to perform static characteristic analysis on the scaled-down three-dimensional model of the test frame based on the stress-strain scaling principle and through a static finite element analysis model. The dynamic characteristic analysis module is used to perform finite element analysis calculations of the natural frequencies of the scaled-down three-dimensional model of the test frame, and to extract the 1st to 6th order modes for dynamic characteristic analysis.

7. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1-5.

8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1-5.

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