Real-time balance fatigue stress monitoring method, electronic equipment and storage medium

Abstract

The invention discloses a balance fatigue stress real-time monitoring method, electronic equipment and a storage medium, and belongs to the technical field of wind tunnel test. In order to solve the problem of real-time monitoring of fatigue stress of a test balance, the method comprises the following steps: constructing a balance model by using ANSYS software, performing finite element mesh division on the constructed balance model, calculating a finite element solution of the balance model after mesh division under a designed pneumatic load, and obtaining a finite element analysis result of the balance model; extracting a stress node close to the yield strength of the balance as a high-risk stress monitoring object, and establishing a stress equation between the aerodynamic load of the balance and the stress node; collecting the aerodynamic load of the balance through data collection equipment, and recording the stress change of the balance in real time; a Goodman straight line graph is used for representing the fatigue characteristic relation of high-risk stress nodes of the balance, and balance fatigue stress real-time monitoring and risk early warning are carried out. The balance can be safely used under the condition of higher load and volume ratio.

Description

Technical Field

[0001] The invention belongs to the technical field of wind tunnel test and measurement, and in particular relates to a real-time monitoring method for fatigue stress of a balance, an electronic device and a storage medium. Background Art

[0002] Before the wind tunnel test, the aircraft test model usually selects a balance with a load range closest to the expected aerodynamic load of the test model. This selection method often ignores the dynamic load on the balance, and the balance will fail under the action of long-term dynamic loads, and in severe cases, cracks or fractures will occur. Fatigue failure has seriously threatened the safety of aerospace, mechanical engineering, transportation and other fields. According to statistics, in various fields of modern industry, about 80% of the damage to parts is caused by fatigue failure, which makes fatigue a key issue to ensure structural safety and life. The probability of balance fatigue failure is higher in harsh dynamic test environments, such as: rotor or propeller force measurement test, the balance must repeatedly withstand alternating dynamic loads; there are also some special types of wind tunnel tests, such as: supercharged variable Reynolds number wind tunnel test, its test model is not only heavier than conventional wind tunnels, but also withstands several times higher aerodynamic loads. In the more than 60 years of strain balance measurement history, many examples of wind tunnel balance fatigue failure have occurred. This will not only damage the balance, but may even cause the test piece to fall off and be blown away along the surface of the wind tunnel, which can lead to catastrophic situations. These accidents often delay the entire development cycle of the aircraft. To ensure the safety of the test, the monitoring of the balance must be based on stress rather than aerodynamic loads, and the monitoring point is not just the location where the strain gauge is attached, but the entire balance structure. Summary of the invention

[0003] The problem to be solved by the present invention is real-time monitoring of fatigue stress of a test balance, and a real-time monitoring method of fatigue stress of a balance, an electronic device and a storage medium are proposed.

[0004] To achieve the above object, the present invention is implemented through the following technical solutions:

[0005] A real-time monitoring method for fatigue stress of a balance comprises the following steps:

[0006] S1. Use ANSYS software to construct a balance model, then perform finite element meshing on the constructed balance model, calculate the finite element solution of the meshed balance model under the designed aerodynamic load, and obtain the finite element analysis result of the balance model;

[0007] S2. Based on the finite element analysis results of the balance model obtained in step S1, the stress nodes close to the yield strength of the balance are extracted as high-risk stress monitoring objects, and the stress equation between the balance aerodynamic load and the stress node is established;

[0008] S3. For the stress node close to the yield strength of the balance obtained in step S2, the pneumatic load of the balance is collected by the data acquisition device, and the stress change of the balance is recorded in real time;

[0009] S4. For the real-time stress change of the balance obtained in step S3, the fatigue characteristic relationship of the high-risk stress nodes of the balance is represented by a Goodman straight line diagram, and real-time monitoring of the fatigue stress of the balance and risk warning are performed.

[0010] Furthermore, in step S1, tetrahedral units are used for finite element meshing, and mesh encryption is performed on the elastic elements of the balance to obtain a finite element mesh with stress nodes, and then the MISES stresses and stress components of the six components of the balance under the designed aerodynamic load are calculated.

[0011] Furthermore, the specific implementation method of step S2 includes the following steps:

[0012] S2.1. For the i-th stress node, establish the stress equation between the balance aerodynamic load and the stress node. The calculation formula is as follows:

[0013]

[0014] in, is the stress tensor of the ith stress node, L m is the mth component of the designed aerodynamic load, is the stress tensor coefficient. There are nine stress components at any stress node of the balance body, σ 11 , σ 22 , σ 33 are the first normal stress component, the second normal stress component, and the third normal stress component, respectively, 12 , σ 13 , σ 21 , σ 23 , σ 31 , σ 32 are the first shear stress component, the second shear stress component, the third shear stress component, the fourth shear stress component, the fifth shear stress component, and the sixth shear stress component respectively;

[0015] S2.2. Take the principal stress as the eigenvalue of the stress tensor, calculate the Mises stress, and then calculate the Mises stress of each combination in the six-component aerodynamic load collected by the balance. Then, sort and classify the stress results, and extract the stress nodes close to the yield strength of the balance as high-risk stress monitoring objects.

[0016] Furthermore, the number of stress nodes close to the balance yield strength described in step S2.2 is 118, including structural load key nodes and strain gauge position nodes, of which there are 72 structural load key nodes and 46 strain gauge position nodes.

[0017] Furthermore, the specific implementation method of step S3 includes the following steps:

[0018] S3.1. The data acquisition device collects the six-component aerodynamic load of the balance, establishes a stress equation between the measured aerodynamic load and the high-risk stress node extracted by finite element calculation, and obtains the real-time stress value of the high-risk stress node as the aerodynamic load changes;

[0019] S3.2. Determine the limit value of stress, refer to the fatigue limit value of the balance material, including the tensile strength limit and fatigue limit of the balance, set the steady-state stress value to the average stress change value of the high-risk stress node, and the dynamic stress value to the difference between the maximum and minimum stress values ​​of the high-risk stress node.

[0020] Furthermore, in step S3.2, the tensile strength limit of the balance is 760 MPa, and the fatigue limit is 400 MPa.

[0021] Furthermore, in step S4, a Goodman straight line diagram is used to represent the relationship between the average stress and stress amplitude of the high-risk stress node of the balance and the fatigue characteristics of the balance. The Goodman straight line formula is as follows:

[0022]

[0023] Among them, σ a is the stress amplitude, σ -1 is the fatigue limit of the material under symmetrical cyclic loading, σ m is the mean stress, σ b is the ultimate strength of the material.

[0024] An electronic device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of a method for real-time monitoring of fatigue stress of a balance when executing the computer program.

[0025] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the method for real-time monitoring of fatigue stress of a balance.

[0026] Beneficial effects of the present invention:

[0027] The real-time monitoring method for fatigue stress of a balance described in the present invention makes the monitoring of balance performance in the process of wind tunnel testing more diversified, transforming from the previous single voltage value static monitoring to the dynamic instantaneous load and stress monitoring, and more clearly grasping the information of the balance test process. A higher range of load envelopes for the balance can be obtained, and the wind tunnel test is no longer limited to the design load of the balance, but is determined by the real-time stress monitoring result value of the balance, so that a wider range of test data can be obtained, further expanding the high Reynolds number capability of the wind tunnel. The present invention can be used in the entire process of balance calibration, installation, and testing, and can improve the design of the balance, optimize the safety factor, and ensure the safe use of the balance under higher load to volume ratios. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a flow chart of a method for real-time monitoring of fatigue stress of a balance according to the present invention;

[0029] Figure 2 This is the balance fatigue limit curve of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the specific embodiments described are only part of the embodiments of the present invention, rather than all of the specific embodiments. The components of the specific embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations, and the present invention can also have other embodiments.

[0031] Therefore, the following detailed description of the specific embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected specific embodiments of the present invention. Based on the specific embodiments of the present invention, all other specific embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0032] In order to further understand the content, features and effects of the present invention, the following specific implementation methods are given as examples, and the attached Figure 1 and attached Figure 2 The detailed instructions are as follows:

[0033] Embodiment 1:

[0034] A real-time monitoring method for fatigue stress of a balance comprises the following steps:

[0035] S1. Use ANSYS software to construct a balance model, then perform finite element meshing on the constructed balance model, calculate the finite element solution of the meshed balance model under the designed aerodynamic load, and obtain the finite element analysis result of the balance model;

[0036] Furthermore, in step S1, tetrahedral units are used to perform finite element meshing, mesh encryption is performed on the elastic elements of the balance, a finite element mesh with stress nodes is obtained, and then the MISES stresses and stress components of the six components of the balance under the designed aerodynamic load are calculated;

[0037] Furthermore, 810,000 nodes were divided;

[0038] S2. Based on the finite element analysis results of the balance model obtained in step S1, the stress nodes close to the yield strength of the balance are extracted as high-risk stress monitoring objects, and the stress equation between the balance aerodynamic load and the stress node is established;

[0039] Furthermore, the specific implementation method of step S2 includes the following steps:

[0040] S2.1. For the i-th stress node, establish the stress equation between the balance aerodynamic load and the stress node. The calculation formula is as follows:

[0041]

[0042] in, is the stress tensor of the ith stress node, L m is the mth component of the designed aerodynamic load, is the stress tensor coefficient. There are nine stress components at any stress node of the balance body, σ 11 , σ 22 , σ 33 are the first normal stress component, the second normal stress component, and the third normal stress component, respectively, 12 , σ 13 , σ 21 , σ 23 , σ 31 , σ 32 are the first shear stress component, the second shear stress component, the third shear stress component, the fourth shear stress component, the fifth shear stress component, and the sixth shear stress component respectively;

[0043] S2.2. Take the principal stress as the eigenvalue of the stress tensor, calculate the Mises stress, and then calculate the Mises stress of each combination of the six-component aerodynamic loads collected by the balance. Then sort and classify the stress results, and extract the stress nodes close to the yield strength of the balance as high-risk stress monitoring objects;

[0044] Furthermore, the number of stress nodes close to the balance yield strength described in step S2.2 is 118, including key structural load nodes and strain gauge position nodes, of which 72 are key structural load nodes and 46 are strain gauge position nodes;

[0045] S3. For the stress node close to the yield strength of the balance obtained in step S2, the pneumatic load of the balance is collected by the data acquisition device, and the stress change of the balance is recorded in real time;

[0046] Furthermore, the specific implementation method of step S3 includes the following steps:

[0047] S3.1. The data acquisition device collects the six-component aerodynamic load of the balance, establishes a stress equation between the measured aerodynamic load and the high-risk stress node extracted by finite element calculation, and obtains the real-time stress value of the high-risk stress node as the aerodynamic load changes;

[0048] S3.2. Determine the limit value of stress, refer to the fatigue limit value of the balance material, including the tensile strength limit and fatigue limit of the balance, set the steady-state stress value to the average stress change value of the high-risk stress node, and the dynamic stress value to the difference between the maximum and minimum stress values ​​of the high-risk stress node.

[0049] Furthermore, in step S3.2, the tensile strength limit of the balance is 760 MPa, and the fatigue limit is 400 MPa.

[0050] Furthermore, the maximum local stress at each node cannot exceed the infinite life region in the Goodman fatigue limit diagram. Once it enters the finite life region in the upper right corner, it will affect the service life of the balance. The data acquisition equipment can also separate the steady-state and dynamic components of the load and node stress at a rate of up to 1KHz;

[0051] S4. For the real-time stress change of the balance obtained in step S3, the fatigue characteristic relationship of the high-risk stress nodes of the balance is represented by a Goodman straight line diagram, and real-time monitoring of the fatigue stress of the balance and risk warning are performed.

[0052] Furthermore, in step S4, a Goodman straight line diagram is used to represent the relationship between the average stress and stress amplitude of the high-risk stress node of the balance and the fatigue characteristics of the balance. The Goodman straight line formula is as follows:

[0053]

[0054] Among them, σ a is the stress amplitude, σ -1 is the fatigue limit of the material under symmetrical cyclic loading, σ m is the mean stress, σ b is the ultimate strength of the material.

[0055] Figure 2 Point B indicates that the size of the static load on the balance is equal to the tensile strength of the material, and fatigue failure will not occur at this time. Point A indicates that the symmetrical fatigue limit of the material is obtained by laboratory testing under symmetrical cycles, and fatigue failure will not occur at this time. Connect these two points, and the points on the curve have the same fatigue life. The upper right side of the curve is the finite life area, and the lower left side is the infinite life area.

[0056] Embodiment 2:

[0057] An electronic device includes a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of a real-time monitoring method for fatigue stress of a balance described in Example 1 when executing the computer program.

[0058] The computer device of the present invention may be a device including a processor and a memory, such as a single chip microcomputer including a central processing unit, etc. Moreover, the processor is used to implement the steps of the above-mentioned method for real-time monitoring of fatigue stress of a balance when executing the computer program stored in the memory.

[0059] The processor may be a central processing unit (CPU), other general-purpose 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, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0060] The memory may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area may store data created according to the use of the mobile phone (such as audio data, a phone book, etc.), etc. In addition, the memory may include a high-speed random access memory, and may also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0061] Embodiment 3:

[0062] A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements a method for real-time monitoring of fatigue stress of a balance as described in Example 1.

[0063] The computer-readable storage medium of the present invention can be any form of storage medium that can be read by a processor of a computer device, including but not limited to non-volatile memory, volatile memory, ferroelectric memory, etc. A computer program is stored on the computer-readable storage medium. When the processor of the computer device reads and executes the computer program stored in the memory, the steps of the above-mentioned method for real-time monitoring of fatigue stress of a balance can be implemented.

[0064] The computer program includes computer program code, which may be in source code form, object code form, executable file or some intermediate form, etc. The computer readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic 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 may 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.

[0065] Although the present application has been described above with reference to specific embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, as long as there is no structural conflict, the various features in the specific embodiments disclosed in the present application may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A real-time monitoring method for fatigue stress of a balance, characterized in that: The steps include: S1. Use ANSYS software to construct a balance model, then perform finite element meshing on the constructed balance model, calculate the finite element solution of the meshed balance model under the designed aerodynamic load, and obtain the finite element analysis result of the balance model; S2. Based on the finite element analysis results of the balance model obtained in step S1, the stress nodes close to the yield strength of the balance are extracted as high-risk stress monitoring objects, and the stress equation between the balance aerodynamic load and the stress node is established; S3. For the stress node close to the yield strength of the balance obtained in step S2, the pneumatic load of the balance is collected by the data acquisition device, and the stress change of the balance is recorded in real time; S4. For the real-time stress change of the balance obtained in step S3, the fatigue characteristic relationship of the high-risk stress nodes of the balance is represented by a Goodman straight line diagram, and real-time monitoring of the fatigue stress of the balance and risk warning are performed.

2. A real-time monitoring method for fatigue stress of a balance according to claim 1, characterized in that: In step S1, tetrahedral units are used to perform finite element mesh division, and the elastic elements of the balance are meshed to obtain a finite element mesh with stress nodes, and then the MISES stress and stress components of the six components of the balance under the designed aerodynamic load are calculated.

3. A real-time monitoring method for fatigue stress of a balance according to claim 2, characterized in that: The specific implementation method of step S2 includes the following steps: S2.

1. For the i-th stress node, establish the stress equation between the balance aerodynamic load and the stress node. The calculation formula is as follows: in, is the stress tensor of the ith stress node, L m is the mth component of the designed aerodynamic load, is the stress tensor coefficient. There are nine stress components at any stress node of the balance body, σ 11 , σ 22 , σ 33 are the first normal stress component, the second normal stress component, and the third normal stress component, respectively, 12 , σ 13 , σ 21 , σ 23 , σ 31 , σ 32 are the first shear stress component, the second shear stress component, the third shear stress component, the fourth shear stress component, the fifth shear stress component, and the sixth shear stress component respectively; S2.

2. Take the principal stress as the eigenvalue of the stress tensor, calculate the Mises stress, and then calculate the Mises stress of each combination in the six-component aerodynamic load collected by the balance. Then, sort and classify the stress results, and extract the stress nodes close to the yield strength of the balance as high-risk stress monitoring objects.

4. A real-time monitoring method for fatigue stress of a balance according to claim 3, characterized in that: The number of stress nodes close to the balance yield strength described in step S2.2 is 118, including structural load key nodes and strain gauge position nodes, of which there are 72 structural load key nodes and 46 strain gauge position nodes.

5. A real-time monitoring method for fatigue stress of a balance according to claim 4, characterized in that: The specific implementation method of step S3 includes the following steps: S3.

1. The data acquisition device collects the six-component aerodynamic load of the balance, establishes a stress equation between the measured aerodynamic load and the high-risk stress node extracted by finite element calculation, and obtains the real-time stress value of the high-risk stress node as the aerodynamic load changes; S3.

2. Determine the limit value of stress, refer to the fatigue limit value of the balance material, including the tensile strength limit and fatigue limit of the balance, set the steady-state stress value to the average stress change value of the high-risk stress node, and the dynamic stress value to the difference between the maximum and minimum stress values ​​of the high-risk stress node.

6. A real-time monitoring method for fatigue stress of a balance according to claim 5, characterized in that: The tensile strength limit of the balance in step S3.2 is 760 MPa, and the fatigue limit is 400 MPa.

7. A real-time monitoring method for fatigue stress of a balance according to claim 6, characterized in that: Step S4 uses the Goodman straight line diagram to represent the relationship between the average stress and stress amplitude of the high-risk stress node of the balance and the fatigue characteristics of the balance. The Goodman straight line formula is as follows: Among them, σ a is the stress amplitude, σ -1 is the fatigue limit of the material under symmetrical cyclic loading, σ m is the mean stress, σ b is the ultimate strength of the material.

8. An electronic device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of a method for real-time monitoring of fatigue stress of a balance as claimed in any one of claims 1 to 7 when executing the computer program.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, a real-time monitoring method for fatigue stress of a balance as described in any one of claims 1 to 7 is implemented.

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