Helicopter multi-frequency vibration intensity comprehensive analysis method and device

Abstract

The present application relates to the field of helicopter structure strength design, and relates to a comprehensive analysis method and device for helicopter multi-frequency vibration strength. The method comprises: obtaining vibration data of key measuring points of a certain configuration at different speeds; performing frequency spectrum analysis according to the vibration data of the key measuring points to obtain amplitude values corresponding to different frequencies; and obtaining a comprehensive vibration level of the configuration according to the amplitude values corresponding to the different frequencies.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of helicopter structure strength design, and relates to a helicopter multi-frequency vibration strength comprehensive analysis method and device. BACKGROUND

[0002] The helicopter structure change will cause the change of the excitation frequency of a key measuring point. At present, the evaluation method of the vibration level change of the key measuring point before and after the structure change is to compare the vibration level of a single frequency by the traditional mode, and it is difficult to obtain reliable results. Therefore, it is necessary to propose a method for giving the comprehensive vibration level of multiple frequencies of a key measuring point. SUMMARY

[0003] The application proposes a method for evaluating the comprehensive vibration level of a key measuring point under the action of multiple frequencies for the first time, and applies it to practice. The application takes the actual vibration problem of a certain type of machine and the solution to the vibration problem as the background, obtains an engineering design method of the helicopter multi-frequency vibration strength comprehensive analysis method, and verifies the correctness and feasibility of the multi-frequency vibration strength comprehensive analysis method through engineering flight verification. The method can be used for evaluating the engineering design of the key measuring point under the multi-frequency vibration strength, and has high engineering value in vibration problem troubleshooting and vibration control plan.

[0004] TECHNICAL SCHEME

[0005] In a first aspect, a helicopter multi-frequency vibration strength comprehensive analysis method is provided, comprising:

[0006] Obtaining vibration data of a key measuring point of a certain configuration at different speeds;

[0007] Performing spectrum analysis on the vibration data of the key measuring point to obtain amplitude values corresponding to different frequencies;

[0008] Obtaining the comprehensive vibration level of the configuration according to the amplitude values corresponding to different frequencies.

[0009] Further, the comprehensive vibration level of the configuration is composed of A' at different speeds, and A' is the amplitude value of the equivalent comprehensive vibration acceleration after superposition of all vibration frequencies with the reference frequency f0 as the reference;

[0010] The calculation formula of A' is:

[0011] ;

[0012] f1, f2, …, f n are different frequencies analyzed by spectrum analysis; A1, A2, …, A n are corresponding acceleration amplitudes. n f1, f2, …, f

[0013] Further, the method further comprises:

[0014] acquiring the comprehensive vibration level of different configurations;

[0015] comparing the comprehensive vibration level of different configurations to analyze the performance of the key measuring point.

[0016] Further, the method further comprises:

[0017] plotting the comprehensive vibration level diagram of the configuration, wherein the speed is the horizontal coordinate and the amplitude of the equivalent comprehensive vibration acceleration is the vertical coordinate.

[0018] In a second aspect, a comprehensive analysis device for helicopter multi-frequency vibration intensity is provided, comprising:

[0019] a first acquisition module for acquiring vibration data of a key measuring point of a certain configuration at different speeds;

[0020] an analysis module for performing frequency spectrum analysis on the vibration data of the key measuring point to obtain amplitudes corresponding to different frequencies;

[0021] a second acquisition module for acquiring the comprehensive vibration level of the configuration according to the amplitudes corresponding to different frequencies.

[0022] Further, the comprehensive vibration level of the configuration is composed of A' at different speeds, and A' is the amplitude of the equivalent comprehensive vibration acceleration after superposition of all vibration frequencies with the reference frequency f0 as the reference;

[0023] The calculation formula of A' is:

[0024] ;

[0025] f1, f2, …, f n are different frequencies analyzed by frequency spectrum analysis; A1, A2, …, A n are the amplitudes of the corresponding accelerations of f1, f2, …, f n .

[0026] Further, the device further comprises:

[0027] a third acquisition module for acquiring the comprehensive vibration level of different configurations;

[0028] a comparison module for comparing the comprehensive vibration level of different configurations to analyze the performance of the key measuring point.

[0029] Further, the device further comprises:

[0030] a plotting module for plotting the comprehensive vibration level diagram of the configuration, wherein the speed is the horizontal coordinate and the amplitude of the equivalent comprehensive vibration acceleration is the vertical coordinate.

[0031] Beneficial effects: provide a comprehensive analysis method and device for helicopter multi-frequency vibration intensity, which can obtain true and meet the safety monitoring requirements of key measuring points before and after structural changes, and provide accurate and reliable vibration level evaluation method for strength design. The application ensures the safety monitoring requirements of key points of structural changes in flight test, and provides accurate and reliable vibration level evaluation method for helicopter strength design, which can more accurately carry out strength design, has high universality and engineering application value. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a flowchart of a comprehensive analysis method for helicopter multi-frequency vibration intensity provided by the application;

[0033] Figure 2 is a schematic diagram of frequency spectrum analysis of measured vibration data at the tail reduction of configuration I involved in the application;

[0034] Figure 3 is a schematic diagram of frequency spectrum analysis of measured vibration data at the tail reduction of configuration II involved in the application;

[0035] Figure 4 is a schematic diagram of comprehensive vibration level comparison of measured data of configurations I and II involved in the application. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the application clearer, the technical scheme in the application will be described in more detail below in combination with the drawings in the application. In the drawings, the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The described embodiments are part of the embodiments of the application, not all embodiments. The embodiments described below by reference to the drawings are exemplary and are intended to explain the application, and cannot be understood as limiting the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application. The embodiments of the application will be described in detail below in combination with the drawings.

[0037] In the description of the application, it should be understood that the terms "center", "axial", "vertical", "upper", "lower", "upper end", "bottom end", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the scope of protection of the application.

[0038] The application is based on vibration data of a certain type of flight test phase, and the evaluation method of comprehensive vibration level of key measuring points under the action of multiple frequencies. The basic formula involved in the application is as follows:

[0039] The sinusoidal vibration displacement is represented as

[0040] (1)

[0041] The acceleration of sinusoidal vibration is represented as:

[0042] (2)

[0043] Then (3)

[0044] Wherein, A represents the amplitude of vibration acceleration;

[0045] f represents frequency;

[0046] S represents displacement;

[0047] The acceleration of vibration is represented as;

[0048] A s represents the amplitude of displacement;

[0049] t represents time;

[0050] For the vibration of two different frequencies of the key measuring point, it is assumed that and The acceleration amplitudes are both A, and the ratio of the influence of the two on the structure converted to displacement is:

[0051] (4)

[0052] The equivalent acceleration after superposition of two frequencies is considered as:

[0053] (5)

[0054] The general form is derived: for multiple frequency vibration accelerations f1, f2, …, f n The acceleration amplitudes are all A1, A2, …, A n , the reference frequency is selected as f0, and the equivalent comprehensive vibration acceleration amplitude A' after superposition of all vibration frequencies is:

[0055] (6)

[0056] As shown in Figure 1 , the specific steps are as follows:

[0057] [1] In the process of scientific research flight of a certain type of aircraft, the vibration data of key measuring points in the effective time period of configuration I flight test data are subjected to spectral analysis; the rotational frequency f1 of the key measuring points occupies an absolute dominant position in the vibration level, and the rotational frequency f2 occupies an absolute secondary position in the vibration level;

[0058] [2] In the process of scientific research flight of a certain type of aircraft, the vibration data of key measuring points in the effective time period of configuration II flight test data are subjected to spectral analysis; the rotational frequency f2 of the key measuring points occupies an absolute dominant position in the vibration level, and the rotational frequency f1 occupies an absolute secondary position in the vibration level;

[0059] [3] For configuration I, the load amplitude corresponding to the rotational frequency f1 and the rotational frequency f2 of each flight state of the key measuring points is listed;

[0060] [4] The comprehensive vibration level of the two series of data is obtained by using the formula (1) to formula (6) of the present application;

[0061] [5] For configuration II, the load amplitude corresponding to the rotational frequency f1 and the rotational frequency f2 of the key measuring points in approximately the same flight state is listed;

[0062] [6] The comprehensive vibration level of the two series of data is obtained by using the formula (1) to formula (6) of the present application;

[0063] [7] Two series of data, i.e. the comprehensive vibration level of the measured vibration level of the rotational frequency f1 and f2 of the key points, are formed for configurations I and II, and a scatter plot of the two series of data is drawn.

[0064] The specific process is as follows by analyzing and comparing the measured data of a certain type of aircraft:

[0065] S1, in the process of scientific research flight of a certain type of aircraft, the vibration data of the tail reduction of configuration I flight test data in the effective time period are subjected to spectral analysis; the rotational frequency 2Ω t occupies an absolute dominant position in the vibration level, and the rotational frequency 4Ω t occupies an absolute secondary position in the vibration level; the configuration I tail reduction measured vibration data spectral analysis diagram is shown in Figure 2 ;

[0066] S2, in the process of scientific research flight of a certain type of aircraft, the vibration data of the key measuring points in the effective time period of configuration II flight test data are subjected to spectral analysis; the rotational frequency 4Ω t occupies an absolute dominant position in the vibration level, and the rotational frequency 2Ω t occupies an absolute secondary position in the vibration level; the configuration II tail reduction measured vibration data spectral analysis diagram is shown in Figure 3 ;

[0067] S3, for configuration I, list the key measurement points each flight state rotating speed frequency 2Ω t and rotating speed frequency 4Ω t corresponding load amplitude;

[0068] S4, using the formula (1)~formula (6) of the application, obtain the comprehensive vibration level of two series of data; configuration I comprehensive vibration level see table 1;

[0069] Table 1 two configuration tail rotor comprehensive vibration data comparison

[0070]

[0071] S5, for configuration II, list the key measurement points approximately same flight state rotating speed frequency 2Ω t and rotating speed frequency 4Ω t corresponding load amplitude;

[0072] S6, using the formula (1)~formula (6) of the application, obtain the comprehensive vibration level of two series of data; configuration II comprehensive vibration level see table 1;

[0073] S7, for configuration I and II form two data series, namely the key point rotating speed frequency 2Ω t and 4Ω t the measured data of the comprehensive vibration level, draw two series of data scatter plot see Figure 4 .

[0074] Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This application is intended to cover any variations, uses or adaptive changes of this disclosure that follow, in general, the principles of the disclosure and include known equivalents or technical possibilities within the scope of the disclosure but not disclosed by the disclosure. The specification and examples are only regarded as exemplary, and the true scope and spirit of the disclosure are indicated by the following claims.

[0075] It should be understood that the present disclosure is not limited to the precise structures described above and shown in the drawings and that various modifications and changes can be made without departing from its scope. The scope of the present disclosure is only limited by the appended claims.

Claims

1. A method of comprehensive analysis of the multi-frequency vibration strength of a helicopter, characterized in that, The method comprises: obtaining vibration data of a key measuring point of a certain configuration at different speeds; performing spectrum analysis on the vibration data of the key measuring point to obtain amplitude values corresponding to different frequencies; obtaining a comprehensive vibration level of the configuration according to the amplitude values corresponding to different frequencies; For two different frequencies of vibration of a key point, the ratio of the effects on the structure, converted to displacement, is and with both having an acceleration amplitude of A. ； an equivalent acceleration amplitude after superposition of two frequencies is: ； deduce to a general form: the comprehensive vibration level of the configuration is composed of A' at different speeds, A' being an equivalent comprehensive vibration acceleration amplitude after superposition of all vibration frequencies with a reference frequency f0 as a reference; a calculation formula of A' is: ； f1, f2,..., f n are different frequencies analyzed for the spectrum; A1, A2,..., A n are f1, f2,..., f n corresponding acceleration amplitudes.

2. The method of claim 1, wherein, The method further comprises: obtaining comprehensive vibration levels of different configurations; comparing the comprehensive vibration levels of different configurations to analyze the performance of the key measuring point.

3. The method of claim 2, wherein, The method further comprises: drawing a comprehensive vibration level diagram of the configuration, wherein the speed is the horizontal coordinate and the equivalent comprehensive vibration acceleration amplitude is the vertical coordinate.

4. A comprehensive analysis device for multi-frequency vibration strength of a helicopter, characterized by comprising: The method comprises: a first obtaining module for obtaining vibration data of a key measuring point of a certain configuration at different speeds; an analysis module for performing spectrum analysis on the vibration data of the key measuring point to obtain amplitude values corresponding to different frequencies; a second obtaining module for obtaining a comprehensive vibration level of the configuration according to the amplitude values corresponding to different frequencies; For two different frequencies of vibration of a key point, the ratio of the effect on the structure, converted to displacement, is and with both having an acceleration amplitude of A, is ； an equivalent acceleration amplitude after superposition of two frequencies is: ； deduce to a general form: the comprehensive vibration level of the configuration is composed of A' at different speeds, A' being an equivalent comprehensive vibration acceleration amplitude after superposition of all vibration frequencies with a reference frequency f0 as a reference; a calculation formula of A' is: ； f1, f2,..., f n are different frequencies analyzed for the spectrum; A1, A2,..., A n are f1, f2,..., f n corresponding acceleration amplitudes.

5. The apparatus of claim 4, wherein, The device further comprises: a third obtaining module for obtaining comprehensive vibration levels of different configurations; a comparison module for comparing the comprehensive vibration levels of different configurations to analyze the performance of the key measuring point.

6. The apparatus of claim 5, wherein, The device further comprises: a drawing module for drawing a comprehensive vibration level diagram of the configuration, wherein the speed is the horizontal coordinate and the equivalent comprehensive vibration acceleration amplitude is the vertical coordinate.

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