Method and system for evaluating narrow-band co-vibration stress response of thin-wall stator part

Abstract

The invention relates to the technical field of aero-engines, and discloses a thin-wall stator piece narrow-band co-vibration stress response evaluation method and system, and the method comprises the steps: carrying out the filtering processing of a frequency spectrum signal, eliminating the influence of a background noise signal on response evaluation, and carrying out the calculation of the response evaluation according to the vibration response. The vibration response is divided into several frequency bands with large vibration response from a frequency domain, the vibration response of each frequency band is analyzed, the response of each frequency band is superposed based on a vibration mode superposition and probability distribution model, and finally the vibration response of the whole frequency band is obtained. According to the method, the strain of the thin-wall stator part can be effectively evaluated when the thin-wall stator part vibrates at the same time under a plurality of narrow bands, and basic support is provided for high-cycle fatigue design of the thin-wall stator part.

Description

Technical Field

[0001] The invention relates to the technical field of aero-engines and discloses a method and a system for evaluating the narrow-band resonant vibration stress response of a thin-walled stator component. Background Art

[0002] Thin-walled stators are extensively used in aircraft engine afterburner and nozzle components. These components, while enduring extremely high temperature loads, are also subject to various vibration excitation loads, including airflow pressure fluctuations, noise, and the engine rotor fundamental frequency. Due to their inherently weak structural rigidity and their large, full-circuit construction, thin-walled stators exhibit a rich variety of modal states, making it difficult to completely avoid these excitation frequencies during design, leading to resonance issues. Unlike the single-frequency vibration response of engine blades, the vibration response of thin-walled stator structures exhibits obvious narrowband resonance characteristics and no obvious main frequency characteristics. Since blade vibration has obvious single-frequency characteristics, the maximum vibration response point is usually used directly for evaluation when performing response evaluation. In view of the narrowband resonance characteristics of thin-walled stator components, if the single-frequency response is used as a reference for blade vibration evaluation, the vibration response at other frequencies will be ignored, resulting in a vibration response that is significantly smaller than the actual result; however, if the total vibration amount is directly used for evaluation, if effective filtering cannot be performed, the calculated vibration response will be far greater than the actual response, which is not conducive to structural design. Summary of the Invention

[0003] The purpose of the present invention is to provide a method and system for evaluating the narrow-band resonant vibration stress response of thin-walled stator components, which can realize effective evaluation of the strain of thin-walled stator components when they vibrate simultaneously in multiple narrow bands, and provide basic support for the high-cycle fatigue design of thin-walled stator components.

[0004] In order to achieve the above technical effects, the technical solution adopted by the present invention is: A method for evaluating the narrow-band resonant vibration stress response of a thin-walled stator component comprises: Performing spectrum analysis on the vibration response data of the thin-walled stator to obtain the maximum strain amplitude in the vibration response data; Eliminating background noise from the vibration response data to construct a noise-reduced three-dimensional waterfall graph; intercepting a frequency spectrum at a time point corresponding to a maximum strain amplitude on the three-dimensional waterfall graph, and extracting a local peak point on the frequency spectrum; Determine a local peak point whose peak value is greater than a preset peak value and whose absolute value of the frequency difference between two adjacent local peak points is greater than a preset frequency difference as the main frequency of the frequency band; Taking each main frequency as the center and extending to both sides on the spectrum diagram, the boundary frequency value when the strain amplitude at n consecutive frequencies is less than the preset amplitude is determined as the frequency band boundary of the corresponding main frequency, forming the effective frequency band of the corresponding main frequency; Performing an inverse Fourier transform on the strain amplitude in each effective frequency band in the three-dimensional waterfall diagram to obtain a total strain amplitude function of a single effective frequency band based on the time domain; The total strain amplitude functions of all valid frequency bands are superimposed to obtain the strain amplitude function in the full frequency domain. The root mean square of the strain amplitude in the full frequency domain per unit time is calculated based on the strain amplitude function in the full frequency domain. The probability density function of the root mean square of the strain amplitude in the full frequency domain per unit time is statistically analyzed to determine the +3σ value of the strain amplitude in the full frequency domain as the multi-narrowband resonant vibration response value.

[0005] Furthermore, the method for eliminating background noise from the vibration response data includes: screening, based on the vibration response data, non-vibration frequencies having a strain amplitude less than a first preset strain threshold during the entire working time; Calculate the average value μ and (μ+3σ) of all non-vibration frequency strain amplitudes; if the average value μ is less than a second preset strain threshold, determine the average value μ as the background noise amplitude; if the average value μ is greater than the second preset strain threshold, determine the (μ+3σ) value as the background noise amplitude; The strain amplitude at each frequency is subtracted from the background noise amplitude to obtain the vibration response signal after the background noise is eliminated.

[0006] Furthermore, the first preset strain threshold is 0.1 times the maximum value of the strain amplitude, and the second preset strain threshold is 0.05 times the maximum value of the strain amplitude.

[0007] Furthermore, the preset peak value is 0.01 to 0.2 times the maximum value of the strain amplitude.

[0008] Furthermore, before calculating the root mean square of the strain amplitude in the full frequency domain per unit time according to the strain amplitude function in the full frequency domain, the ratio of the total strain amplitude in each effective frequency band to the vibration response amplitude in the full frequency domain is pre-calculated, the effective frequency bands whose ratio is less than a preset ratio value are deleted, and then the probability density function of the root mean square of the vibration response in each unit time is calculated.

[0009] To achieve the above technical effects, the present invention further provides a system for evaluating the narrow-band resonant vibration stress response of a thin-walled stator component, which is used to implement the above-mentioned method for evaluating the narrow-band resonant vibration stress response of a thin-walled stator component, comprising: A data acquisition module is used to perform spectrum analysis on the vibration response data of the thin-walled stator component to obtain the maximum strain amplitude in the vibration response data; a preprocessing module for eliminating background noise from the vibration response data and constructing a noise-reduced three-dimensional waterfall graph; intercepting a frequency spectrum at a time point corresponding to a maximum strain amplitude on the three-dimensional waterfall graph, and extracting a local peak point on the frequency spectrum; A main frequency determination module, configured to determine a local peak point whose local peak point is greater than a preset peak value and whose absolute value of the frequency difference between two adjacent local peak points is greater than a preset frequency difference value as the main frequency of the frequency band; An effective frequency band determination module is configured to take each main frequency as the center and extend to both sides of the spectrum diagram to determine the boundary frequency value when the strain amplitude at n consecutive frequencies is less than a preset amplitude as the frequency band boundary of the corresponding main frequency, thereby forming an effective frequency band of the corresponding main frequency; a conversion module, configured to perform an inverse Fourier transform on the strain amplitude within each effective frequency band in the three-dimensional waterfall diagram to obtain a total strain amplitude function of a single effective frequency band based on the time domain; The response analysis module is used to superimpose the total strain amplitude functions of all valid frequency bands to obtain the strain amplitude function in the full frequency domain; calculate the root mean square of the strain amplitude in the full frequency domain per unit time based on the strain amplitude function in the full frequency domain, calculate the probability density function of the root mean square of the strain amplitude in the full frequency domain per unit time, and determine the +3σ value of the strain amplitude in the full frequency domain as the multi-narrowband resonant vibration response value.

[0010] Furthermore, the preprocessing module further includes: A frequency screening unit, configured to screen out non-vibration frequencies having a strain amplitude less than a first preset strain threshold value during the entire working time according to the vibration response data; a strain amplitude analysis unit, configured to calculate an average value μ and a (μ+3σ) value of all non-vibration frequency strain amplitudes; if the average value μ is less than a second preset strain threshold, determining the average value μ as the background noise amplitude; and if the average value μ is greater than the second preset strain threshold, determining the (μ+3σ) value as the background noise amplitude; The denoising unit is used to subtract the background noise amplitude from the strain amplitude at each frequency to obtain the vibration response signal after the background noise is eliminated.

[0011] Furthermore, in the frequency screening unit, the first preset strain threshold is 0.1 times the maximum strain amplitude; and in the strain amplitude analysis unit, the second preset strain threshold is 0.05 times the maximum strain amplitude.

[0012] Furthermore, in the main frequency determination module, the preset peak value is 0.01 to 0.2 times the maximum value of the strain amplitude.

[0013] Furthermore, before calculating the root mean square of the strain amplitude in the full frequency domain per unit time according to the strain amplitude function in the full frequency domain, the response analysis module pre-calculates the ratio of the total strain amplitude in each effective frequency band to the vibration response amplitude in the full frequency domain, deletes the effective frequency bands whose ratio is less than a preset ratio value, and then calculates the probability density function of the root mean square of the vibration response in each unit time.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention filters the spectral signal to eliminate the influence of the background noise signal on the response evaluation, and then divides the vibration response into several frequency bands with larger vibration responses in the frequency domain according to the size of the vibration response. The vibration response of each frequency band is analyzed separately, and the responses of each frequency band are superimposed based on the mode superposition and probability distribution model, so as to finally obtain the vibration response of the entire frequency band; the effective evaluation of the strain of thin-walled stators when vibrating simultaneously in multiple narrow bands is realized, which provides basic support for the high-cycle fatigue design of thin-walled stators. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Flowchart of the method for evaluating the narrow-band resonant vibration stress response of a thin-walled stator component in Example 1 or 2; Figure 2 This is a structural block diagram of the narrow-band resonant vibration stress response evaluation system for thin-walled stator components in Example 1; Figure 3 This is a spectrum diagram of the vibration response of the thin-walled stator before background noise elimination in Example 2; Figure 4 This is a spectrum diagram of the vibration response of the thin-walled stator after background noise is eliminated in Example 2; Figure 5 : is a local peak function diagram of the spectrum diagram of the thin-walled stator in Example 2; Figure 6 This is the effective vibration frequency band diagram determined by analysis in Example 2; Figure 7 This is the probability density distribution diagram of the vibration response in Example 2.

[0016] Among them, 1. Data acquisition module; 2. Preprocessing module; 3. Main frequency determination module; 4. Effective frequency band determination module; 5. Conversion module; 6. Response analysis module; 201. Frequency screening unit; 202. Strain amplitude analysis unit; 203. De-noising unit. DETAILED DESCRIPTION

[0017] The present invention will be described in further detail below with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the present invention to the following embodiments, as all technologies implemented based on the present invention fall within the scope of the present invention.

[0018] Example 1 See also Figure 1 and Figure 2 , a method for evaluating the narrow-band resonant vibration stress response of thin-walled stator components, comprising: Performing spectrum analysis on the vibration response data of the thin-walled stator to obtain the maximum strain amplitude in the vibration response data; Eliminating background noise from the vibration response data to construct a noise-reduced three-dimensional waterfall graph; intercepting a frequency spectrum at a time point corresponding to a maximum strain amplitude on the three-dimensional waterfall graph, and extracting a local peak point on the frequency spectrum; Determine a local peak point whose peak value is greater than a preset peak value and whose absolute value of the frequency difference between two adjacent local peak points is greater than a preset frequency difference as the main frequency of the frequency band; Taking each main frequency as the center and extending to both sides on the spectrum diagram, the boundary frequency value when the strain amplitude at n consecutive frequencies is less than the preset amplitude is determined as the frequency band boundary of the corresponding main frequency, forming the effective frequency band of the corresponding main frequency; Performing an inverse Fourier transform on the strain amplitude in each effective frequency band in the three-dimensional waterfall diagram to obtain a total strain amplitude function of a single effective frequency band based on the time domain; The total strain amplitude functions of all valid frequency bands are superimposed to obtain the strain amplitude function in the full frequency domain. The root mean square of the strain amplitude in the full frequency domain per unit time is calculated based on the strain amplitude function in the full frequency domain. The probability density function of the root mean square of the strain amplitude in the full frequency domain per unit time is statistically analyzed to determine the +3σ value of the strain amplitude in the full frequency domain as the multi-narrowband resonant vibration response value.

[0019] In this embodiment, after filtering the spectral signal to eliminate the influence of the background noise signal on the response evaluation, the vibration response is divided into several frequency bands with larger vibration responses in the frequency domain according to the size of the vibration response. The vibration response of each frequency band is analyzed separately, and the responses of each frequency band are superimposed based on the mode superposition and probability distribution model, and finally the vibration response of the entire frequency band is obtained; the effective evaluation of the strain of thin-walled stators when vibrating simultaneously in multiple narrow bands is realized, which provides basic support for the high-cycle fatigue design of thin-walled stators.

[0020] Based on the same inventive concept, this embodiment further provides a system for evaluating the narrow-band resonant vibration stress response of a thin-walled stator component, which is used to implement the aforementioned method for evaluating the narrow-band resonant vibration stress response of a thin-walled stator component, comprising: Data acquisition module 1, used to perform spectrum analysis on the vibration response data of the thin-walled stator component to obtain the maximum strain amplitude in the vibration response data; Preprocessing module 2 is used to eliminate background noise from the vibration response data and construct a noise-reduced three-dimensional waterfall chart; intercept the frequency spectrum of the time point corresponding to the maximum strain amplitude on the three-dimensional waterfall chart, and extract local peak points on the frequency spectrum; A main frequency determination module 3 is configured to determine a local peak point whose local peak point is greater than a preset peak value and whose absolute value of the frequency difference between two adjacent local peak points is greater than a preset frequency difference as the main frequency of the frequency band; The effective frequency band determination module 4 is configured to extend toward both sides of the spectrum graph with each main frequency as the center, and determine the boundary frequency value when the strain amplitude at n consecutive frequencies is less than a preset amplitude as the frequency band boundary of the corresponding main frequency, thereby forming an effective frequency band of the corresponding main frequency; A conversion module 5 is configured to perform an inverse Fourier transform on the strain amplitude in each effective frequency band in the three-dimensional waterfall diagram to obtain a total strain amplitude function of a single effective frequency band based on the time domain; Response analysis module 6 is used to superimpose the total strain amplitude functions of all valid frequency bands to obtain the strain amplitude function in the full frequency domain; calculate the root mean square of the strain amplitude in the full frequency domain per unit time based on the strain amplitude function in the full frequency domain, calculate the probability density function of the root mean square of the strain amplitude in the full frequency domain per unit time, and determine the +3σ value of the strain amplitude in the full frequency domain as the multi-narrowband resonant vibration response value.

[0021] In this embodiment, the pre-processing module 2 further includes: A frequency screening unit 201 is configured to screen out non-vibration frequencies having a strain amplitude less than a first preset strain threshold value during the entire working time according to the vibration response data; The strain amplitude analysis unit 202 is configured to calculate an average value μ and a value (μ+3σ) of all non-vibration frequency strain amplitudes. If the average value μ is less than a second preset strain threshold, the average value μ is determined to be the background noise amplitude. If the average value μ is greater than the second preset strain threshold, the value (μ+3σ) is determined to be the background noise amplitude. The denoising unit 203 is configured to subtract the background noise amplitude from the strain amplitude at each frequency to obtain a vibration response signal after the background noise is eliminated.

[0022] Example 2 See also Figure 1 、 Figures 3 to 7 , a method for evaluating the narrow-band resonant vibration stress response of thin-walled stator components, comprising: Step 1: Performing spectrum analysis on the vibration response data of the thin-walled stator to obtain the maximum strain amplitude in the vibration response data; In this embodiment, the original vibration signal of the thin-walled stator (such as Figure 3) to perform spectrum analysis to determine the maximum value of the vibration stress response (i.e. strain) of the thin-walled stator in the full frequency range under the working environment , providing a benchmark for subsequent vibration signal noise reduction and determination of effective frequency bandwidth.

[0023] Step 2: Eliminate background noise from the vibration response data to construct a noise-reduced three-dimensional waterfall chart; intercept a frequency spectrum at a time point corresponding to the maximum strain amplitude on the three-dimensional waterfall chart, and extract a local peak point on the frequency spectrum; In this embodiment, the frequency spectrum change curve during the entire working time is first analyzed to screen out the frequencies whose strains are basically unchanged during the entire working time. These frequency strains are all caused by background noise and other signal interference. Calculate the non-vibration frequency; The frequency is The maximum amplitude when The frequency is The minimum amplitude when ; is the non-vibration frequency threshold coefficient, The value of is positively correlated with the calculation result of the threshold. Take 0.1, if the frequency The strain change under the condition is less than the first preset strain threshold , then the frequency Recorded as non-vibration frequency.

[0024] Background noise is a relatively uniform response signal in a wide frequency domain. For the non-vibration frequencies screened out, the average value μ and (μ+3σ) of the amplitude of all non-vibration frequencies are calculated. If the average value μ is less than the second preset strain threshold, the average value μ is selected as the background noise magnitude. If the average value μ is greater than the second preset strain threshold, the (μ+3σ) value is selected as the background noise amplitude. In this embodiment, the second preset strain threshold is 0.05. .

[0025] After determining the background noise level, the true vibration response is separated from the background noise across the entire frequency domain. This is done by subtracting the background noise amplitude from the vibration response amplitude at each frequency to obtain the vibration response signal after background noise removal. If the strain amplitude becomes negative during the calculation, it is set to zero. Figure 4 The vibration response spectrum of the thin-walled stator is given after eliminating the background noise.

[0026] Step 3: Determine as the main frequency of the frequency band a local peak point whose peak point is greater than a preset peak value and whose absolute value of the frequency difference between two adjacent local peak points is greater than a preset frequency difference; In this embodiment, the moment corresponding to the maximum strain amplitude is taken as the analysis object, and the amplitude at a certain frequency is selected to satisfy the formula The data point is taken as the local peak point; The frequency is The strain amplitude at is the frequency accuracy of spectrum analysis, and The frequencies are and The strain amplitude at . Figure 5 The peak function diagram of the spectrum diagram of the thin-walled stator in this embodiment is given. The analysis object is Figure 4 Spectrum diagram in .

[0027] The selected local peak points are further screened. When the amplitude of the local peak point is less than the preset peak value, this data point is deleted. At the same time, if the frequency difference between two consecutive peak points is less than the preset frequency difference, the point with the smaller value between the two peak points is deleted. The remaining points are the main frequencies of each frequency band.

[0028] In this embodiment, the preset peak value is 0.01 to 0.2 times the maximum value of the strain amplitude; the preset frequency difference is determined according to needs.

[0029] Step 4: Taking each main frequency as the center, extending to both sides on the spectrum graph, the boundary frequency value when the strain amplitude at n consecutive frequencies is less than the preset amplitude is determined as the frequency band boundary of the corresponding main frequency, thereby forming the effective frequency band of the corresponding main frequency; In this embodiment, the search is performed outward in the spectrum graph. When the amplitude at n consecutive frequencies is less than the preset amplitude, the judgment is terminated. The frequency value at this time is the left or right boundary of the frequency band. During the analysis process, it is possible that the frequency bands of different main frequencies are connected. In this case, these frequency bands need to be merged and connected to form a valid frequency band corresponding to the main frequency. Figure 6 The diagram of the effective vibration frequency band determined analytically is given.

[0030] Step 5: Perform inverse Fourier transform on the strain amplitude in each effective frequency band in the three-dimensional waterfall diagram to obtain a total strain amplitude function of a single effective frequency band based on the time domain; In this embodiment, the response within each effective frequency band is calculated according to Perform inverse Fourier transform to obtain the total vibration response of a single frequency band ;in is the left boundary frequency of the corresponding effective frequency band, is the right boundary frequency of the corresponding effective frequency band, The frequency is The strain amplitude at The frequency is The vibration phase angle at .

[0031] Step 6: Superimpose the total strain amplitude functions of all effective frequency bands to obtain the strain amplitude function in the full frequency domain; In this step, the calculation method of the strain amplitude function in the full frequency domain is the same as that in step 5, except that the calculation range is extended from a single frequency band to the entire frequency domain, and the filtered signal is analyzed.

[0032] Step 7: Calculate the ratio of the total strain amplitude of each effective frequency band to the vibration response amplitude in the entire frequency domain, and delete the effective frequency bands whose ratio is less than a preset ratio value; In this embodiment, in addition to calculating the total amount, it is also necessary to compare the proportion of vibration responses in different frequency bands. For frequency bands with a smaller proportion, they need to be trimmed in subsequent analysis to improve analysis efficiency.

[0033] Step 8: Calculate the root mean square of the strain amplitude in the full frequency domain per unit time based on the strain amplitude function in the full frequency domain, calculate the probability density function of the root mean square of the strain amplitude in the full frequency domain per unit time, and determine the +3σ value of the strain amplitude in the full frequency domain (i.e., the average value plus 3 times the standard deviation) as the multi-narrowband resonant vibration response value.

[0034] In this embodiment, after obtaining the time domain result of the vibration, the unit time Δt is used as the period to calculate RMS , calculate the probability density function of the root mean square of the vibration response in each unit time, and determine the +3σ value of the vibration response . This is the calculated narrow-band resonant vibration stress response value. Figure 7 The probability density distribution diagram of the vibration response is given.

[0035] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for evaluating the narrow-band resonant vibration stress response of a thin-walled stator component, characterized in that: include: Performing spectrum analysis on the vibration response data of the thin-walled stator to obtain the maximum strain amplitude in the vibration response data; Eliminating background noise from the vibration response data to construct a noise-reduced three-dimensional waterfall graph; intercepting a frequency spectrum at a time point corresponding to a maximum strain amplitude on the three-dimensional waterfall graph, and extracting a local peak point on the frequency spectrum; Determine a local peak point whose peak value is greater than a preset peak value and whose absolute value of the frequency difference between two adjacent local peak points is greater than a preset frequency difference as the main frequency of the frequency band; Taking each main frequency as the center and extending to both sides on the spectrum diagram, the boundary frequency value when the strain amplitude at n consecutive frequencies is less than the preset amplitude is determined as the frequency band boundary of the corresponding main frequency, forming the effective frequency band of the corresponding main frequency; Performing an inverse Fourier transform on the strain amplitude in each effective frequency band in the three-dimensional waterfall diagram to obtain a total strain amplitude function of a single effective frequency band based on the time domain; The total strain amplitude functions of all valid frequency bands are superimposed to obtain the strain amplitude function in the full frequency domain. The root mean square of the strain amplitude in the full frequency domain per unit time is calculated based on the strain amplitude function in the full frequency domain. The probability density function of the root mean square of the strain amplitude in the full frequency domain per unit time is statistically analyzed to determine the +3σ value of the strain amplitude in the full frequency domain as the multi-narrowband resonant vibration response value.

2. The method for evaluating the narrow-band resonant vibration stress response of a thin-walled stator according to claim 1, characterized in that: The method for eliminating background noise from the vibration response data includes: screening, based on the vibration response data, non-vibration frequencies having a strain amplitude less than a first preset strain threshold during the entire working time; Calculate the average value μ and (μ+3σ) of all non-vibration frequency strain amplitudes; if the average value μ is less than a second preset strain threshold, determine the average value μ as the background noise amplitude; if the average value μ is greater than the second preset strain threshold, determine the (μ+3σ) value as the background noise amplitude; The strain amplitude at each frequency is subtracted from the background noise amplitude to obtain the vibration response signal after the background noise is eliminated.

3. The method for evaluating the narrow-band resonant vibration stress response of a thin-walled stator according to claim 2, characterized in that: The first preset strain threshold is 0.1 times the maximum strain amplitude, and the second preset strain threshold is 0.05 times the maximum strain amplitude.

4. The method for evaluating the narrow-band resonant vibration stress response of a thin-walled stator according to claim 1, characterized in that: The preset peak value is 0.01 to 0.2 times the maximum value of the strain amplitude.

5. The method for evaluating the narrow-band resonant vibration stress response of a thin-walled stator according to claim 1, characterized in that: Before calculating the root mean square of the strain amplitude in the full frequency domain per unit time according to the strain amplitude function in the full frequency domain, the ratio of the total strain amplitude in each valid frequency band to the vibration response amplitude in the full frequency domain is pre-calculated, the valid frequency bands with a ratio less than a preset ratio value are deleted, and then the probability density function of the root mean square of the vibration response in each unit time is calculated.

6. A system for evaluating the narrow-band resonant vibration stress response of a thin-walled stator component, for implementing the method for evaluating the narrow-band resonant vibration stress response of a thin-walled stator component according to claim 1, characterized in that: include: A data acquisition module is used to perform spectrum analysis on the vibration response data of the thin-walled stator component to obtain the maximum strain amplitude in the vibration response data; A preprocessing module, configured to eliminate background noise from the vibration response data and construct a three-dimensional waterfall chart after noise reduction; intercepting a frequency spectrum at a time point corresponding to a maximum strain amplitude value on the three-dimensional waterfall graph, and extracting a local peak point on the frequency spectrum; A main frequency determination module, configured to determine a local peak point whose local peak point is greater than a preset peak value and whose absolute value of the frequency difference between two adjacent local peak points is greater than a preset frequency difference as the main frequency of the frequency band; An effective frequency band determination module is configured to take each main frequency as the center and extend to both sides of the spectrum diagram to determine the boundary frequency value when the strain amplitude at n consecutive frequencies is less than a preset amplitude as the frequency band boundary of the corresponding main frequency, thereby forming an effective frequency band of the corresponding main frequency; a conversion module, configured to perform an inverse Fourier transform on the strain amplitude within each effective frequency band in the three-dimensional waterfall diagram to obtain a total strain amplitude function of a single effective frequency band based on the time domain; The response analysis module is used to superimpose the total strain amplitude functions of all valid frequency bands to obtain the strain amplitude function in the full frequency domain; calculate the root mean square of the strain amplitude in the full frequency domain per unit time based on the strain amplitude function in the full frequency domain, calculate the probability density function of the root mean square of the strain amplitude in the full frequency domain per unit time, and determine the +3σ value of the strain amplitude in the full frequency domain as the multi-narrowband resonant vibration response value.

7. The thin-walled stator component narrow-band resonant vibration stress response evaluation system according to claim 6, characterized in that: The pre-processing module also includes: A frequency screening unit, configured to screen out non-vibration frequencies having a strain amplitude less than a first preset strain threshold value during the entire working time according to the vibration response data; a strain amplitude analysis unit, configured to calculate an average value μ and a (μ+3σ) value of all non-vibration frequency strain amplitudes; if the average value μ is less than a second preset strain threshold, determining the average value μ as the background noise amplitude; and if the average value μ is greater than the second preset strain threshold, determining the (μ+3σ) value as the background noise amplitude; The denoising unit is used to subtract the background noise amplitude from the strain amplitude at each frequency to obtain the vibration response signal after the background noise is eliminated.

8. The thin-walled stator component narrow-band resonant vibration stress response evaluation system according to claim 7, characterized in that: In the frequency screening unit, the first preset strain threshold is 0.1 times the maximum strain amplitude; in the strain amplitude analysis unit, the second preset strain threshold is 0.05 times the maximum strain amplitude.

9. The system for evaluating the narrow-band resonance stress response of thin-walled stator components according to claim 6, characterized in that: In the main frequency determination module, the preset peak value is 0.01 to 0.2 times the maximum value of the strain amplitude.

10. The system for evaluating the narrow-band resonance stress response of thin-walled stator components according to claim 6, characterized in that: Before calculating the root mean square of the strain amplitude in the full frequency domain per unit time according to the strain amplitude function in the full frequency domain, the response analysis module pre-calculates the ratio of the total strain amplitude in each valid frequency band to the vibration response amplitude in the full frequency domain, deletes the valid frequency bands whose ratio is less than a preset ratio value, and then calculates the probability density function of the root mean square of the vibration response in each unit time.

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