An aircraft structure frequency domain vibration fatigue analysis method, electronic equipment and medium

Abstract

The application belongs to the technical field of aircraft structure dynamic strength calculation and analysis, and particularly relates to an aircraft structure frequency domain vibration fatigue analysis method, an electronic device and a medium. Vibration fatigue life analysis can be carried out by only obtaining a power spectral density function of a vibration stress through random vibration response analysis at the initial stage of aircraft design, numerical calculation is easy to master, the calculation time is short, the shortcomings that the traditional rain flow counting method needs time domain data of the vibration stress and is time-consuming in calculation can be effectively overcome, the method is used for vibration fatigue life calculation of aircraft structure in aircraft design, can provide a reference for aircraft structure vibration fatigue life analysis and design, and is helpful for rapid iteration and optimization of the structure scheme.

Description

Technical Field

[0001] This application belongs to the field of aircraft structural dynamic strength calculation and analysis technology, specifically involving an aircraft structural frequency domain vibration fatigue analysis method and electronic equipment and medium. Background Technology

[0002] In aircraft dynamic strength design, structural vibration fatigue life calculation is usually carried out in the time domain and frequency domain. Among them, the rainflow counting method is commonly used to calculate the vibration fatigue life of the structure in the time domain. The advantage of this method is that the calculation accuracy is relatively high.

[0003] The vibrations of aircraft structures are mostly high-frequency vibrations, such as those of fuselage and wing structures. Using the rainflow counting method requires time-domain data of structural vibration stress cycles. This time-domain data cannot be obtained through analysis and calculation, but can only be obtained through actual vibration measurements. Moreover, the amount of time-domain data of vibration stress cycles is extremely large, which requires a lot of time to calculate the vibration fatigue life of the structure.

[0004] In view of the aforementioned technical deficiencies, this application is hereby filed. Summary of the Invention

[0005] The purpose of this application is to address the problem that the current rainflow counting method for calculating the fatigue life of aircraft structures requires a large amount of time domain data and incurs huge time costs. This application provides a frequency domain vibration fatigue analysis method for aircraft structures, as well as electronic equipment and media. The method is a frequency domain vibration fatigue analysis method based on the vibration stress power spectral density function, in order to overcome or mitigate at least one of the known technical defects.

[0006] The technical solution of this application is:

[0007] A method for frequency domain vibration fatigue analysis of aircraft structures, comprising:

[0008] Step 1: Based on the analysis results of the random vibration response of the aircraft structure, obtain the vibration stress power spectral density function. ;

[0009] Step 2: Vibration stress power spectral density function based on aircraft structure Calculate the power spectral density of vibration stress Step Moment ;

[0010] Step 3: Vibration stress power spectral density based on aircraft structure Step Moment Calculate intermediate parameters , , , , :

[0011] ; ;

[0012] ; ; ;

[0013] ; ;

[0014] in, , For process parameters;

[0015] Step 4: Calculate the characteristic parameters of the material based on the material fatigue SN curve of the aircraft structure. :

[0016] ;

[0017] in, This is the negative reciprocal of the slope of the material fatigue SN curve in a double logarithmic coordinate system;

[0018] For stress level, For fatigue life;

[0019] Step 5: Calculate the fatigue damage caused by continuous stress in the aircraft structure. :

[0020] ;

[0021] ;

[0022] in, This represents the upper limit of the integral stress level.

[0023] For intermediate parameters;

[0024] Step 6: Calculate the vibration fatigue life of the aircraft structure. :

[0025] .

[0026] According to at least one embodiment of this application, in the above-described method for frequency domain vibration fatigue analysis of aircraft structures, in step one, a finite element model of aircraft structure dynamics is established, and random vibration response analysis is performed.

[0027] According to at least one embodiment of this application, in the above-described method for frequency domain vibration fatigue analysis of aircraft structures, step two specifically comprises:

[0028] ;

[0029] in, The frequency is the vibration frequency.

[0030] According to at least one embodiment of this application, in the above-described method for frequency domain vibration fatigue analysis of aircraft structures, in step two, the vibration stress power spectral density is calculated. Step Moment Up to level 4.

[0031] According to at least one embodiment of this application, in the above-described method for frequency domain vibration fatigue analysis of aircraft structures, in step four, the material fatigue SN curve is obtained by consulting a material handbook.

[0032] According to at least one embodiment of this application, in the above-described method for frequency domain vibration fatigue analysis of aircraft structures, in step four, the material fatigue SN curve is obtained based on the analysis of experimental results.

[0033] According to at least one embodiment of this application, in the above-described method for frequency domain vibration fatigue analysis of aircraft structures, in step five, .

[0034] An electronic device, comprising:

[0035] processor;

[0036] The memory stores a computer program configured to implement the above-described method for frequency domain vibration fatigue analysis of aircraft structures when executed by the processor.

[0037] According to at least one embodiment of this application, in the above-described electronic device, the processor and memory are connected via a bus system, which may be a serial or parallel communication bus.

[0038] A computer-readable storage medium storing a computer program that, when executed by a processor, enables the implementation of the aforementioned method for frequency domain vibration fatigue analysis of aircraft structures. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the frequency domain vibration fatigue analysis method for aircraft structures provided in the embodiments of this application;

[0040] Figure 2 This is a schematic diagram illustrating the calculation of material characteristic parameters based on the material fatigue SN curve of the aircraft structure, as provided in an embodiment of this application.

[0041] To better illustrate this embodiment, some content in the accompanying drawings may be omitted, enlarged, or reduced. They are for illustrative purposes only and should not be construed as limiting the scope of this application. Detailed Implementation

[0042] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, and other related parts can be referred to the general design.

[0043] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The word "comprising" as used in this application description indicates that the concept preceding the word encompasses the concepts listed following the word and their equivalents, without excluding other related concepts.

[0044] A method for frequency domain vibration fatigue analysis of aircraft structures, such as Figure 1 As shown.

[0045] Step 1: Based on the analysis results of the random vibration response of the aircraft structure, obtain the vibration stress power spectral density function. .

[0046] A finite element model of aircraft structural dynamics is established, and random vibration response analysis is performed to obtain the vibration stress power spectral density function. It is possible to obtain only the vibration stress power spectral density function of the part of interest. Vibration stress power spectral density function It is the vibration frequency The corresponding one-sided stress power spectral density.

[0047] Step 2: Vibration stress power spectral density function based on aircraft structure Calculate the power spectral density of vibration stress Step Moment Typically, calculations are performed up to the 4th order.

[0048] ……………………(1)

[0049] in, The frequency is the vibration frequency.

[0050] Step 3: Vibration stress power spectral density based on aircraft structure Step Moment Calculate intermediate parameters , , , , :

[0051] ……………………(2)

[0052] ……………………(3)

[0053] ……………………(4)

[0054] ……………………(5)

[0055] ……………………(6)

[0056] ……………………(7)

[0057] ……………………(8)

[0058] ……………………(9)

[0059] in, , , For process parameters, Specifically, it is the expected value of the number of stress amplitudes per unit time, expressed in the form of moments of the stress power spectral density.

[0060] The probability density function of vibration stress amplitude can be further constructed:

[0061] …………………(10)

[0062] ……………………(11)

[0063] in, This is an intermediate parameter.

[0064] Step 4: Calculate the characteristic parameters of the material based on the material fatigue SN curve of the aircraft structure. :

[0065] ……………………(12)

[0066] in, Let be a material constant, and be the negative reciprocal of the slope of the material fatigue SN curve in a double logarithmic coordinate system, such as... Figure 2 As shown;

[0067] For stress level, This refers to fatigue life.

[0068] The fatigue SN curve of the material is obtained by consulting the material handbook or by analyzing the test results.

[0069] Step 5: Calculate the fatigue damage caused by continuous stress in the aircraft structure. :

[0070] …………………(13)

[0071] in, This represents the upper limit of the integral stress level for broadband random vibration. Take 3 times the 0th moment of the vibration stress power spectral density, that is .

[0072] Step 6: Calculate the vibration fatigue life of the aircraft structure. :

[0073] ……………………(14).

[0074] Calculated vibration fatigue life of aircraft structure The unit is seconds (s). To calculate flight hours, divide by 3600.

[0075] Practice has proven that the frequency domain vibration fatigue analysis method for aircraft structures disclosed in the above embodiments yields results consistent with those obtained by the time-domain rainflow counting method, exhibiting similar calculation accuracy. However, it eliminates the need for time-domain data testing of aircraft vibration stress. Vibration fatigue life analysis can be conducted in the early stages of aircraft design simply by obtaining the power spectral density function of vibration stress through random vibration response analysis. Utilizing numerical calculations, it is easy to master and has a short calculation time, effectively overcoming the shortcomings of the traditional rainflow counting method, which requires time-domain data of vibration stress and is time-consuming. When used for structural vibration fatigue life calculation in aircraft design, it can provide a reference for the design of aircraft structural vibration fatigue life analysis and facilitate rapid iterative optimization of structural schemes.

[0076] Another aspect provides an electronic device, comprising:

[0077] processor;

[0078] The memory stores a computer program configured to implement the above-described method for frequency domain vibration fatigue analysis of aircraft structures when executed by the processor.

[0079] In some alternative embodiments, the processor may be a central processing unit (CPU) or other form of processing unit with data processing and / or instruction execution capabilities, may be a general-purpose processor or a special-purpose processor, and may control other components in the compensation electronics to perform the desired functions.

[0080] In some alternative embodiments, the memory may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. Volatile memory may be random access memory (RAM) and / or cache memory, while non-volatile memory may be read-only memory (ROM), hard disk, flash memory, etc. Computer programs may be stored on the memory, and the processor runs these programs to implement the functions described in the embodiments of this application and / or other desired functions. Furthermore, various application programs and various data may also be stored on the memory.

[0081] In some alternative embodiments, the processor and memory can be connected via a bus system, which can be a serial or parallel communication bus, etc.

[0082] It should be noted that, for clarity and brevity, not all the components of the electronic device are shown in the above embodiments. In order to realize the necessary functions of the electronic device, those skilled in the art can provide or set other components not shown according to specific needs.

[0083] For the electronic device disclosed in the above embodiments, since its processor can implement the above-described aircraft structure frequency domain vibration fatigue analysis method when executing the computer program stored in its memory, its technical effects can be referred to the technical effects of the above-described aircraft structure frequency domain vibration fatigue analysis method, and will not be repeated here.

[0084] Another aspect provides a computer-readable storage medium storing a computer program that, when executed by a processor, enables the implementation of the aforementioned method for frequency domain vibration fatigue analysis of aircraft structures.

[0085] In some alternative embodiments, the computer-readable storage medium may include a memory card of a smartphone, a storage component of a tablet computer, a hard disk of a personal computer, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), portable compact disc read-only memory (CD-ROM), flash memory, or any combination of the above storage media, or other suitable storage media.

[0086] The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to mutually. In the absence of conflict, the embodiments and technical features in the embodiments of this application can be combined to obtain new embodiments.

[0087] The technical solution of this application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A method for frequency domain vibration fatigue analysis of aircraft structures, characterized in that, include: Step 1: Based on the analysis results of the random vibration response of the aircraft structure, obtain the vibration stress power spectral density function. ; Step 2: Vibration stress power spectral density function based on aircraft structure Calculate the power spectral density of vibration stress Step Moment ; Step 3: Vibration stress power spectral density based on aircraft structure Step Moment Calculate intermediate parameters , , , , : ； ； ； ； ； ； ； in, , For process parameters; Step 4: Calculate the characteristic parameters of the material based on the material fatigue SN curve of the aircraft structure. : ； in, This is the negative reciprocal of the slope of the material fatigue SN curve in a double logarithmic coordinate system; For stress level, For fatigue life; Step 5: Calculate the fatigue damage caused by continuous stress in the aircraft structure. : ； ； in, This represents the upper limit of the integral stress level. For intermediate parameters; Step 6: Calculate the vibration fatigue life of the aircraft structure. : 。 2. The method for frequency domain vibration fatigue analysis of aircraft structures according to claim 1, characterized in that, In step one, a finite element model of the aircraft's structural dynamics is established, and random vibration response analysis is performed.

3. The method for frequency domain vibration fatigue analysis of aircraft structures according to claim 2, characterized in that, Step two is as follows: ； in, The frequency is the vibration frequency.

4. The method for frequency domain vibration fatigue analysis of aircraft structures according to claim 3, characterized in that, In step two, the vibration stress power spectral density is calculated. Step Moment Up to level 4.

5. The method for frequency domain vibration fatigue analysis of aircraft structures according to claim 4, characterized in that, In step four, the material fatigue SN curve is obtained by consulting the material handbook.

6. The method for frequency domain vibration fatigue analysis of aircraft structures according to claim 4, characterized in that, In step four, the material fatigue SN curve is obtained based on the analysis of experimental results.

7. The method for frequency domain vibration fatigue analysis of aircraft structures according to claim 5 or 6, characterized in that, In step five, .

8. An electronic device, characterized in that, include: processor; The memory stores a computer program configured to implement the frequency domain vibration fatigue analysis method for aircraft structures as described in claim 7 when executed by the processor.

9. The electronic device according to claim 8, characterized in that, The processor and memory are connected via a bus system, which can be a serial or parallel communication bus.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, enables the implementation of the frequency domain vibration fatigue analysis method for aircraft structures as described in claim 7.

Images