Blade maximum vibration stress design method and system based on small sample test data

Abstract

The application discloses a kind of blade maximum vibration stress design method and system based on small sample test data, this method adjusts the parameter of each finite element model after constructing finite element model, and the change of model parameter will produce vibration localization of different degrees, then, the finite element model that vibration difference between different blades is maximum is screened out, i.e. the finite element model that vibration localization is most serious is screened out, it is used as each corresponding optimization model of resonance frequency order, and the vibration localization factor of each resonance frequency order is calculated, then, the actual maximum vibration stress of each resonance frequency order in the sense of statistics is calculated based on vibration localization factor, so that the actual maximum vibration stress of blade with high confidence can be obtained based on small sample test data, without needing to carry out multiple dynamic stress measurement test, reduce test cost, improve efficiency.

Description

Technical Field

[0001] This invention relates to the field of high-cycle fatigue assessment technology for engine blades, and in particular, to a method and system for designing maximum vibration stress of blades based on small sample test data, electronic equipment, and computer-readable storage medium. Background Technology

[0002] High-cycle fatigue assessment of aero-gas turbine engine blades is an important part of the "Airworthiness Regulations for Aero-engines". High-cycle fatigue assessment based on vibration-strain test data is one of the conventional methods. Currently, existing methods directly convert the maximum strain corresponding to each order obtained from the test into vibration stress values, and then consider a margin on these converted values ​​as the statistically significant maximum vibration stress value for high-cycle fatigue assessment. Specifically, the process of converting the maximum vibration stress in existing methods includes the following steps: 1) Performing finite element analysis of vibration characteristics to obtain the sensitivity of each test location at each order; 2) Conducting dynamic stress tests to obtain the stress test values ​​at each measuring point at each order; 3) Dividing the stress test value at the location of maximum sensitivity by the maximum sensitivity to directly obtain the maximum vibration stress.

[0003] However, in the dynamic stress testing of aero-gas turbine engine blades, strain gauge survival rate is low and effective data is scarce. If the maximum vibration stress with high confidence is estimated based on small sample test data, a seriously inflated value will be obtained, for example, more than three times the mean. This is obviously a serious deviation from the actual situation, resulting in poor design accuracy of the maximum vibration stress and failure of subsequent high-cycle fatigue assessment, causing unnecessary design iterations. Furthermore, existing technologies do not consider the impact of vibration localization on vibration. Vibration localization is a dynamic phenomenon unique to non-ideal periodic structures (such as blade disks), where the vibration energy of the structure is no longer uniformly distributed along the entire structure, but is "captured" in local areas (such as defect locations, stiffness abrupt changes, and near boundaries), vibrating significantly only in local areas, while the vibration amplitude in other areas is weak or even negligible. If the test location is selected in other areas, the measured value may be a weak vibration amplitude, rather than the ideal maximum value. Therefore, existing technologies usually require multiple adjustments to the test location and multiple dynamic stress measurement experiments to accurately determine the maximum vibration stress with high confidence, resulting in high cost and low efficiency. Therefore, existing technologies cannot design accurate and high-confidence maximum vibration stress for blades with small sample test data. Summary of the Invention

[0004] This invention provides a method and system for designing the maximum vibration stress of a blade based on small sample test data, as well as an electronic device and a computer-readable storage medium. It can obtain the actual maximum vibration stress of the blade with high confidence based on small sample test data, without the need for multiple dynamic stress measurement tests, thereby reducing test costs and improving efficiency.

[0005] According to one aspect of the present invention, a method for designing the maximum vibration stress of a blade based on small sample test data is provided, comprising the following:

[0006] Obtain the dynamic stress measurement test results and get the vibration stress measurement values ​​of all measuring points at each resonance frequency order;

[0007] Construct finite element models corresponding to each resonance frequency order, adjust the parameters of each finite element model, take the finite element model with the largest vibration difference between different blades as the optimization model corresponding to each resonance frequency order, calculate the vibration localization factor of each resonance frequency order, and carry out simulation calculations based on the optimization model to obtain the sensitivity of each patch position under each resonance frequency order.

[0008] Based on the vibration stress measurements at each resonance frequency order at all measuring points and the sensitivity of each patch position, the average value of the converted maximum vibration stress at each resonance frequency order is calculated.

[0009] Based on the vibration localization factor and the average value of the converted maximum vibration stress for each resonance frequency order, the actual maximum vibration stress for each resonance frequency order is calculated.

[0010] Furthermore, the vibration localization factor for each resonant frequency order is calculated based on the following formula:

[0011] ;

[0012] in, Indicates the first i The vibration localization factor of the first resonant frequency. Indicates the first i At the resonant frequency, the maximum vibration stress of the blade with the greatest vibration is... Indicates the first i The maximum vibration stress of the blade with the least vibration at the first resonant frequency.

[0013] Furthermore, the actual maximum vibration stress at each resonant frequency order is calculated based on the following formula:

[0014] ;

[0015] ;

[0016] ;

[0017] in, Indicates the first i The actual maximum vibration stress at the first resonant frequency. Indicates the first i The average maximum vibration stress converted from the first resonance frequency. Indicates a confidence level of p unilateral t Distribution range n Indicates the number of valid experimental data. Indicates the first i The standard deviation of vibration stress at the first resonant frequency. Indicates the first i The positive 3rd order of the vibration stress distribution at the resonant frequency value, Indicates the first i The negative 3 of the vibration stress distribution at the first resonant frequency value, Indicates the first i The vibration localization factor of the first resonant frequency.

[0018] Furthermore, after constructing the finite element model corresponding to each resonant frequency order, the following is also included:

[0019] In the finite element model, spring elements are used to simulate the contact between the blade crown and the tenon and mortise. The stiffness of the spring elements is continuously corrected until the deviation between the calculated resonance frequency of the finite element model and the measured resonance frequency of the dynamic stress measurement test is within the allowable error range.

[0020] Furthermore, after calculating the vibration localization factor for each resonant frequency order, the following is also included:

[0021] Based on the vibration localization factor for each resonance frequency order, the test values ​​of different strain gauges at the same patch location are cleaned.

[0022] Furthermore, the process of cleaning the test values ​​of different strain gauges at the same patch location based on the vibration localization factor for each resonant frequency order includes the following:

[0023] For different strain gauge test values ​​at the same patch location, the maximum and minimum values ​​of vibration stress measurement values ​​at each resonant frequency order are selected. If the ratio of the maximum value to the minimum value is greater than or equal to the preset ratio threshold, the maximum or minimum value is removed, and the ratio is recalculated until the ratio of the maximum value to the minimum value is less than the preset ratio threshold. The preset ratio threshold is obtained by multiplying the vibration localization factor of each resonant frequency order by a preset coefficient.

[0024] Furthermore, the following is included before the step of calculating the average value of the converted maximum vibration stress for each resonant frequency order:

[0025] Calculate the deviation between the equivalent maximum vibration stress at the location of the most sensitive patch and the location of the second most sensitive patch on the same blade. If the deviation is within a preset range, the equivalent maximum vibration stress at the location of the most sensitive patch is taken as the equivalent maximum vibration stress of the blade. If the deviation is not within the preset range, the average of the equivalent maximum vibration stress at the locations of the second most sensitive patch and the most sensitive patch is taken as the equivalent maximum vibration stress of the blade.

[0026] In addition, the present invention also provides a blade maximum vibration stress design system based on small sample test data, comprising:

[0027] The dynamic stress measurement result acquisition module is used to acquire the dynamic stress measurement test results and obtain the vibration stress measurement values ​​of all measuring points at each resonance frequency order.

[0028] The finite element simulation calculation module is used to construct the finite element model corresponding to each resonance frequency order, adjust the parameters of each finite element model, take the finite element model with the largest vibration difference between different blades as the optimization model corresponding to each resonance frequency order, calculate the vibration localization factor of each resonance frequency order, and carry out simulation calculation based on the optimization model to obtain the sensitivity of each patch position under each resonance frequency order.

[0029] The conversion maximum vibration stress calculation module is used to calculate the average conversion maximum vibration stress at each resonance frequency order based on the vibration stress measurement values ​​of all measuring points at each resonance frequency order and the sensitivity of each patch position corresponding to each resonance frequency order.

[0030] The actual maximum vibration stress calculation module is used to calculate the actual maximum vibration stress at each resonance frequency order based on the vibration localization factor and the average value of the converted maximum vibration stress at each resonance frequency order.

[0031] In addition, the present invention also provides an electronic device, including a processor and a memory, wherein the memory stores a computer program, and the processor executes the steps of the method described above by calling the computer program stored in the memory.

[0032] In addition, the present invention provides a computer-readable storage medium for storing a computer program for designing the maximum vibration stress of a blade based on small sample test data, wherein the computer program executes the steps of the method described above when running on a computer.

[0033] The present invention has the following beneficial effects:

[0034] The present invention provides a method for designing the maximum vibration stress of blades based on small sample test data. After constructing a finite element model, the parameters of each finite element model are adjusted. Changes in model parameters will produce different degrees of vibration localization. Then, the finite element model with the greatest vibration difference among different blades, i.e., the finite element model with the most severe vibration localization, is selected as the optimization model corresponding to each resonance frequency order. The vibration localization factor for each resonance frequency order is calculated, and the statistically significant actual maximum vibration stress for each resonance frequency order is estimated based on the vibration localization factor. Thus, a high-confidence actual maximum vibration stress of the blade can be obtained based on small sample test data, without the need for multiple dynamic stress measurement tests, reducing test costs and improving efficiency.

[0035] In addition, the blade maximum vibration stress design system based on small sample test data of the present invention also has the above-mentioned advantages.

[0036] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0037] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0038] Figure 1 This is a flowchart illustrating the blade maximum vibration stress design method based on small sample test data, according to a preferred embodiment of this application.

[0039] Figure 2 This is a schematic diagram showing the distribution of the maximum vibration stress of each blade at a certain vibration frequency in a preferred embodiment of this application.

[0040] Figure 3 This is another flowchart illustrating the blade maximum vibration stress design method based on small sample test data, according to a preferred embodiment of this application.

[0041] Figure 4 This is a schematic diagram showing the distribution of different sensitivity patch positions in a preferred embodiment of this application;

[0042] Figure 5 This is a schematic diagram of the module structure of a blade maximum vibration stress design system based on small sample test data, according to another embodiment of this application. Detailed Implementation

[0043] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0044] Reference Figure 1 A preferred embodiment of this application provides a method for designing the maximum vibration stress of a blade based on small sample test data, including the following:

[0045] Step S1: Obtain the dynamic stress measurement test results and get the vibration stress measurement values ​​of all measuring points at each resonance frequency order;

[0046] Step S2: Construct the finite element model corresponding to each resonance frequency order, adjust the parameters of each finite element model, take the finite element model with the largest vibration difference between different blades as the optimization model corresponding to each resonance frequency order, calculate the vibration localization factor of each resonance frequency order, and carry out simulation calculation based on the optimization model to obtain the sensitivity of each patch position under each resonance frequency order.

[0047] Step S3: Based on the vibration stress measurements of all measuring points at each resonant frequency order and the sensitivity of each patch position, calculate the average value of the converted maximum vibration stress at each resonant frequency order.

[0048] Step S4: Based on the vibration localization factor and the average value of the converted maximum vibration stress for each resonance frequency order, calculate the actual maximum vibration stress for each resonance frequency order.

[0049] It is understood that the blade maximum vibration stress design method based on small sample test data in this embodiment adjusts the parameters of each finite element model after constructing the finite element model. The change of model parameters will produce different degrees of vibration localization. Then, the finite element model with the greatest vibration difference between different blades is selected, that is, the finite element model with the most severe vibration localization is selected, and it is used as the optimization model corresponding to each resonance frequency order. The vibration localization factor of each resonance frequency order is calculated, and the actual maximum vibration stress of each resonance frequency order in a statistical sense is estimated based on the vibration localization factor. Thus, a high-confidence actual maximum vibration stress of the blade can be obtained based on small sample test data, without the need to conduct multiple dynamic stress measurement tests, reducing test costs and improving efficiency.

[0050] In step S1, according to the relevant specifications for the design of test points for blade vibration stress measurement and the technical requirements for blade dynamic stress measurement, a whole-engine vibration stress measurement test is conducted. Strain gauges are attached to the blade under test, and stress data is obtained by measuring the strain during engine operation, thereby obtaining the vibration stress measurement values ​​of all test points at each resonant frequency order. For example, a blade disk has 20 test points and a total of 12 resonant frequencies, which can obtain 20 × 12 test values. For each frequency order, 20 test results can be obtained. Assuming that the 20 test results correspond to 4 test positions (i.e., test point / strain gauge positions), then each test position has 5 test values.

[0051] In addition, in step S2, the aerodynamic excitation force of the blade is first obtained through simulation analysis of the unsteady flow field of the entire ring. Then, a finite element model of the blade disk is established, and the finite element vibration response calculation is performed on the blade disk. For each resonance frequency order, a corresponding finite element model is constructed. For each finite element model, by randomly adjusting the model parameters such as the elastic modulus, density, and mass, different degrees of vibration localization can be generated. Then, the finite element model with the largest vibration difference between different blades, i.e., the finite element model with the most severe vibration localization, is selected as the optimization model corresponding to each resonance frequency order, and the vibration localization factor for each resonance frequency order is calculated. Specifically, the vibration localization factor for each resonance frequency order is calculated based on the following formula:

[0052] ;

[0053] in, Indicates the first i The vibration localization factor of the first resonant frequency. Indicates the first i At the resonant frequency, the maximum vibration stress of the blade with the greatest vibration is... Indicates the first i At the resonant frequency, the maximum vibration stress of the blade with the least vibration is indicated by the first "max" in the subscript, which indicates that this value is the largest among a certain blade, the second "max" indicates that this value is the largest among all blades, and the second "min" indicates that this value is the smallest among all blades.

[0054] For example, assuming each bladed disk has 15 blades, for a certain resonant frequency, after adjusting the model parameters to achieve vibration localization in each simulation, the 15 blades will have 15 vibration maximum values. By comparing the simulation results after multiple adjustments, when the difference between the largest and smallest of the 15 vibration maximum values ​​is the largest, it means that the vibration difference between different blades is the largest, i.e., the vibration localization is the most severe. The finite element model at this point is the optimized model corresponding to that resonant frequency order. The ratio of the maximum vibration stress of the blade with the largest vibration to the maximum vibration stress of the blade with the smallest vibration, output by the finite element model at this point, is used as the vibration localization factor to characterize the vibration localization phenomenon at each resonant frequency order. A schematic diagram of the distribution of the maximum vibration stress of each blade at a certain vibration frequency is shown below. Figure 2 As shown. Then, based on the optimized model corresponding to each resonance frequency order, finite element vibration response simulation calculations are performed to obtain the sensitivity of each patch position at each resonance frequency order. Among them, the simulation analysis of the unsteady flow field of the whole ring, the construction of the finite element model, and the finite element vibration response simulation calculation are all existing technologies, and the specific processes and principles will not be elaborated here.

[0055] In addition, in step S3, the commonly used conversion formula for calculating the maximum vibration stress at a certain resonance frequency order is: ,in, Indicates the first i The first resonant frequency (i.e., the first resonant frequency) i The converted maximum vibration stress of the first mode) Indicates the first i Sensitivity of a patch location at a given resonant frequency. , Indicates the first i The measured vibration stress at the patch location at the resonant frequency is usually converted from the measured vibration stress at the patch location with the highest sensitivity. However, at the same resonant frequency, different blades will have a corresponding converted maximum vibration stress value, and these converted maximum vibration stress values ​​may differ between different blades. Assuming there are... n If valid data exists for each leaf, then the following can be calculated: n The average value of the converted maximum vibration stress corresponding to each blade is calculated using the following formula: ,in, Indicates the first i The average maximum vibration stress converted from the first resonance frequency. This indicates that the first blade is in the [number]th [position]. i The converted maximum vibration stress value at the first resonant frequency. Indicates the first n The first leaf in the i The converted maximum vibration stress value at the first resonance frequency.

[0056] Furthermore, in step S4, the test results will differ for blades from different engines or different blades from the same engine. Therefore, the calculated maximum vibration stress based on the test data does not represent the actual possible maximum vibration stress. Also, due to vibration localization, vibration stress on the same blade disk may be concentrated on only a few blades. For example, assuming a blade disk has 15 blades, each with 4 patch positions, but only 5 of the 15 blades have test values, it cannot be guaranteed that the maximum value of all 15 blades can be measured. Therefore, statistical methods are needed to estimate the actual maximum vibration stress. Thus, this invention assumes that the blade vibration stress caused by blade vibration localization is dispersed, and that the vibration stress of all blades follows a log-normal distribution. Based on the properties of the log-normal distribution, we can obtain: , Indicates the first i The standard deviation of vibration stress at the first resonant frequency. Indicates the first i The positive 3rd order of the vibration stress distribution at the resonant frequency The value, that is, the maximum actual vibration stress. Indicates the first i The negative 3 of the vibration stress distribution at the first resonant frequency The value is the minimum actual maximum vibration stress. In step S2, this invention calculates the vibration localization factor for each resonance frequency order. The essence of the vibration localization factor is the ratio between the maximum vibration stress of the blade with the maximum vibration and the maximum vibration stress of the blade with the minimum vibration. That is, in the actual sample, positive 3 Value and negative 3 The ratio of the two values ​​has similar physical meanings; therefore, this invention uses calculated values ​​to replace theoretical values, that is... Then, combined n Based on the properties of the log-normal distribution, the following valid experimental data can be obtained: ,in, Indicates the first i The actual maximum vibration stress at the first resonant frequency. Indicates a confidence level of p (generally p Take 50% or 95% of the unilateral samples t The distribution interval can be obtained by looking up a table according to different confidence levels. n Indicates the number of valid experimental data. Indicates the first i The vibration localization factor at the first resonant frequency can be used to calculate the actual maximum vibration stress considering the vibration localization factor based on small sample test data. This value can be used for subsequent high-cycle fatigue analysis.

[0057] Understandably, in existing technologies, obtaining a high-probability, high-confidence maximum vibration stress requires either a large amount of test data (typically 50-100 samples), which is obviously uneconomical given the high cost of dynamic stress testing; or estimating the high-probability, high-confidence maximum vibration stress based on a small sample of test data, resulting in a significantly overestimated value, such as more than three times the mean. This deviates significantly from reality and can lead to failure in subsequent high-cycle fatigue assessments, causing unnecessary design iterations. Currently, engineering practice involves directly taking the converted maximum vibration stress from the test data and then considering a margin. However, the converted maximum vibration stress clearly does not fully represent the high-probability, high-confidence maximum vibration stress. This invention defines a vibration localization factor to characterize the vibration localization phenomenon and uses statistical formulas based on this factor to calculate the actual maximum vibration stress of the blade with a high probability and high confidence, even with a small sample of test data. This is more in line with engineering practice, eliminates the need for multiple dynamic stress measurement tests, reduces testing costs, and improves efficiency.

[0058] Furthermore, existing technologies typically design the blade crown and tenon connection as a fixed connection (i.e., the contact tightness remains constant) when performing finite element modeling. However, the contact tightness between the blade crown and the tenon groove varies under different operating conditions, resulting in poor modeling accuracy of the finite element model. This leads to a significant deviation between the calculated resonance frequency of the finite element model and the resonance frequency test results from dynamic stress measurement experiments, thus causing poor accuracy in subsequent model simulation calculations. Optionally, step S2, after constructing the finite element model corresponding to each resonance frequency order, also includes the following:

[0059] In the finite element model, spring elements are used to simulate the contact between the blade crown and the tenon and mortise. The stiffness of the spring elements is continuously corrected until the deviation between the calculated resonance frequency of the finite element model and the measured resonance frequency of the dynamic stress measurement test is within the allowable error range.

[0060] It is understandable that, assuming there are 12 resonant frequencies, changing the stiffness value of a spring element once will cause all 12 resonant frequencies to change. It is difficult to ensure that the deviation between the calculated resonant frequencies of the finite element model and the measured resonant frequencies of the dynamic stress measurement experiment is within the allowable error range by adjusting the stiffness value of the spring element once. Therefore, this invention uses different stiffness values ​​for the spring element for the finite element model corresponding to different resonant frequency orders. For each resonant frequency order, the stiffness of the spring element is adjusted manually iteratively until the deviation between the calculated resonant frequencies of the finite element model and the measured resonant frequencies of the dynamic stress measurement experiment is within the allowable error range. For example, for the 12th resonant frequency... iThe finite element model of the first resonant frequency must satisfy... , , , and ,in, Indicates the first i Calculated value of the first resonance frequency. Indicates the first i The measured value of the first resonant frequency. and They represent the first i +1st order resonance frequency and the first order resonance frequency i The calculated value of the -1st order resonance frequency. and They represent the first i +1st order resonance frequency and the first order resonance frequency i The measured value of the -1st order resonance frequency. and They represent the first i + k The first resonant frequency and the second resonant frequency i - k Calculated value of the first resonance frequency. and They represent the first i + k The first resonant frequency and the second resonant frequency i - k The measured value of the first resonant frequency. k It is an integer, and k >1. Only when the first i The finite element model of the first resonant frequency satisfies the first i When the first-order frequency error is less than 3%, the adjacent-order frequency error is less than 5%, and the frequency errors of other orders are less than 10%, subsequent model parameter adjustments are made. This improves the modeling accuracy of the finite element model for each resonant frequency order, thereby improving the accuracy of subsequent finite element simulation results. Furthermore, in other embodiments of the present invention, the settings of each error threshold (3%, 5%, and 10%) can be adjusted according to actual needs, as long as the first-order frequency error is less than 3%, the adjacent-order frequency error is less than 5%, and the frequency errors of other orders are less than 10%. i The frequency error threshold of the first order must be greater than the frequency error threshold of the adjacent order, and the frequency error threshold of the adjacent order must be greater than the frequency error threshold of the other orders.

[0061] Optional, such as Figure 3 As shown, the blade maximum vibration stress design method based on small sample test data, after calculating the vibration localization factor for each resonance frequency order, also includes the following:

[0062] Step S23: Based on the vibration localization factor of each resonance frequency order, clean the test values ​​of different strain gauges at the same patch location.

[0063] It is understandable that, for the same patch location, due to the influence of vibration localization, the strain gauge test values ​​of different blades at the same patch location will differ. However, the test deviation between the maximum and minimum values ​​should not exceed the vibration localization factor by too much. If it exceeds this factor by too much, it is considered a test error, and test data cleaning is required. Specifically, for different strain gauge test values ​​at the same patch location, the maximum and minimum values ​​of the vibration stress measurement at each resonant frequency order are selected. If the ratio of the maximum to the minimum value is greater than or equal to a preset ratio threshold, the maximum or minimum value is removed, and the ratio is recalculated until the ratio of the maximum to the minimum value is less than the preset ratio threshold. The preset ratio threshold is obtained by multiplying the vibration localization factor at each resonant frequency order by a preset coefficient. Specifically, the calculation is based on the following formula... i The first resonant frequency j Test deviation at each patch location (i.e., the ratio of the maximum to the minimum value): , Indicates the first i The first resonant frequency j The maximum vibration stress test value at each patch location Indicates the first i The first resonant frequency j The minimum vibration stress test value at each patch location, if If so, then data cleaning is not required. Greater than or equal to Then, remove the test value that is furthest from the mean (i.e., the maximum or minimum value). This removed test value is one that is still clearly unreasonable even after considering vibration localization, until the condition is met. After cleaning the test data, proceed to step S3. Additionally, the preset coefficient can be 1.1, 1.3, 1.4, etc., and does not necessarily have to be 1.2; it can be adjusted according to actual needs.

[0064] It is understood that this invention takes into account the influence of test errors. Based on the vibration localization factor of each resonance frequency order, it cleans up the data with excessive test deviations at the same patch position, thereby improving the accuracy of the test data and further improving the calculation accuracy.

[0065] Optionally, step S3 may include the following before calculating the average value of the converted maximum vibration stress for each resonance frequency order:

[0066] Calculate the deviation between the equivalent maximum vibration stress at the location of the most sensitive patch and the location of the second most sensitive patch on the same blade. If the deviation is within a preset range, the equivalent maximum vibration stress at the location of the most sensitive patch is taken as the equivalent maximum vibration stress of the blade. If the deviation is not within the preset range, the average of the equivalent maximum vibration stress at the locations of the second most sensitive patch and the most sensitive patch is taken as the equivalent maximum vibration stress of the blade.

[0067] It is understandable that, for a certain resonant frequency, the equivalent maximum vibration stress is generally calculated from the stress measurement value at the location of the most sensitive patch. Theoretically, the equivalent maximum vibration stress values ​​obtained for different sensitive patch locations should be exactly the same. A schematic diagram of different sensitive patch locations is shown below. Figure 4 As shown, the sensitivity of each patch position is calculated from the mode shape at a certain resonant frequency. However, mode shape calculations have errors, and actual vibration stress measurements also involve testing errors, leading to potentially different converted maximum vibration stress values ​​for patch positions with different sensitivity. Therefore, this invention, considering both mode shape calculation errors and actual testing errors, uses the converted maximum vibration stress value of the second most sensitive patch position to verify the converted maximum vibration stress value for each resonant frequency order.

[0068] Specifically, for the first i First resonant frequency, based on the conversion formula: Calculate the equivalent maximum vibration stress value at the location of the most sensitive patch on the same blade. And the calculated maximum vibration stress value at the location of the second most sensitive patch. ,like If the converted maximum vibration stresses from the two test values ​​are basically consistent, then the converted maximum vibration stress at the location of the maximum sensitivity patch will be determined. The equivalent maximum vibration stress of this blade ,like or If the converted maximum vibration stresses from the two test values ​​are inconsistent, then the converted maximum vibration stress of the blade is calculated based on the following formula: .

[0069] It is understood that this invention considers the influence of model mode shape calculation errors and actual measurement errors. It uses the converted maximum vibration stress value at the second-largest sensitivity patch location for verification. If the deviation between the converted maximum vibration stress value at the second-largest sensitivity patch location and the converted maximum vibration stress value at the largest sensitivity patch location is within 20%, then the influence of model mode shape calculation errors and actual measurement errors is considered small, and the converted maximum vibration stress at the largest sensitivity patch location is directly taken as the converted maximum vibration stress of the blade. If the deviation exceeds 20%, then the influence of model mode shape calculation errors and actual measurement errors is considered large, and the two conversion results are weighted and summed to obtain the converted maximum vibration stress of the blade. This allows for accurate determination of the converted maximum vibration stress value of each blade at each vibration frequency, further improving calculation accuracy. Furthermore, in other embodiments of this invention, the deviation range does not necessarily have to be set to 20%; it can also be set to 10%, 15%, 25%, etc., adjusted according to actual accuracy requirements.

[0070] In addition, such as Figure 5 As shown, another embodiment of the present invention also provides a blade maximum vibration stress design system based on small sample test data, preferably employing the blade maximum vibration stress design method based on small sample test data as described above, including:

[0071] The dynamic stress measurement result acquisition module is used to acquire the dynamic stress measurement test results and obtain the vibration stress measurement values ​​of all measuring points at each resonance frequency order.

[0072] The finite element simulation calculation module is used to construct the finite element model corresponding to each resonance frequency order, adjust the parameters of each finite element model, take the finite element model with the largest vibration difference between different blades as the optimization model corresponding to each resonance frequency order, calculate the vibration localization factor of each resonance frequency order, and carry out simulation calculation based on the optimization model to obtain the sensitivity of each patch position under each resonance frequency order.

[0073] The conversion maximum vibration stress calculation module is used to calculate the average conversion maximum vibration stress at each resonance frequency order based on the vibration stress measurement values ​​of all measuring points at each resonance frequency order and the sensitivity of each patch position corresponding to each resonance frequency order.

[0074] The actual maximum vibration stress calculation module is used to calculate the actual maximum vibration stress at each resonance frequency order based on the vibration localization factor and the average value of the converted maximum vibration stress at each resonance frequency order.

[0075] It is understood that the blade maximum vibration stress design method based on small sample test data in this embodiment adjusts the parameters of each finite element model after constructing the finite element model. The change of model parameters will produce different degrees of vibration localization. Then, the finite element model with the greatest vibration difference between different blades is selected, that is, the finite element model with the most severe vibration localization is selected, and it is used as the optimization model corresponding to each resonance frequency order. The vibration localization factor of each resonance frequency order is calculated, and the actual maximum vibration stress of each resonance frequency order in a statistical sense is estimated based on the vibration localization factor. Thus, a high-confidence actual maximum vibration stress of the blade can be obtained based on small sample test data, without the need to conduct multiple dynamic stress measurement tests, reducing test costs and improving efficiency.

[0076] In addition, the blade maximum vibration stress design system based on small sample test data also includes:

[0077] The test data cleaning module is used to clean the test values ​​of different strain gauges at the same patch location based on the vibration localization factor for each resonance frequency order.

[0078] It is understood that each module of this system embodiment corresponds to each step of the above method embodiment. Therefore, the specific working process and principle of each module will not be repeated here, and can be referred to the above method embodiment.

[0079] In addition, another embodiment of the present invention provides an electronic device including a processor and a memory, wherein the memory stores a computer program, and the processor executes the steps of the method described above by calling the computer program stored in the memory.

[0080] In addition, another embodiment of the present invention provides a computer-readable storage medium for storing a computer program for designing the maximum vibration stress of a blade based on small sample test data, wherein the computer program executes the steps of the method described above when running on a computer.

[0081] Common computer-readable storage media include: floppy disks, flexible disks, hard disks, magnetic tapes, any other magnetic media, CD-ROMs, any other optical media, punch cards, paper tape, any other physical media with perforated patterns, random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), flash erasable programmable read-only memory (FLASH-EPROM), any other memory chips or cartridges, or any other media readable by a computer. Instructions may further be transmitted or received by a transmission medium. The term transmission medium can include any tangible or intangible medium used to store, encode, or carry instructions for execution by a machine, and includes digital or analog carrier communication signals or intangible media that facilitate communication of such instructions. Transmission media include coaxial cables, copper wires, and optical fibers, which contain conductors for transmitting a bus of computer data signals.

[0082] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0083] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0084] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0085] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0086] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0087] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

[0088] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for designing the maximum vibration stress of a blade based on small sample test data, characterized in that, Includes the following: Obtain the dynamic stress measurement test results and get the vibration stress measurement values ​​of all measuring points at each resonance frequency order; Construct finite element models corresponding to each resonance frequency order, adjust the parameters of each finite element model, take the finite element model with the largest vibration difference between different blades as the optimization model corresponding to each resonance frequency order, calculate the vibration localization factor of each resonance frequency order, and carry out simulation calculations based on the optimization model to obtain the sensitivity of each patch position under each resonance frequency order. Based on the vibration stress measurements at each resonance frequency order at all measuring points and the sensitivity of each patch position, the average value of the converted maximum vibration stress at each resonance frequency order is calculated. Based on the vibration localization factor and the average value of the converted maximum vibration stress for each resonance frequency order, the actual maximum vibration stress for each resonance frequency order is calculated. The vibration localization factor for each resonant frequency order is calculated based on the following formula: ； in, Indicates the first The vibration localization factor of the first resonant frequency. Indicates the first At the resonant frequency, the maximum vibration stress of the blade with the greatest vibration is... Indicates the first The maximum vibration stress of the blade with the least vibration at the first resonant frequency; The actual maximum vibration stress at each resonant frequency order is calculated based on the following formula: ； ； ； in, Indicates the first The actual maximum vibration stress at the first resonant frequency. Indicates the first The average maximum vibration stress converted from the first resonance frequency. Indicates a confidence level of p unilateral t Distribution range n Indicates the number of valid experimental data. Indicates the first The standard deviation of vibration stress at the first resonant frequency. Indicates the first The positive distribution of vibration stress at the first resonant frequency value, Indicates the first The negative of the vibration stress distribution at the first resonance frequency value, Indicates the first The vibration localization factor of the first resonant frequency.

2. The blade maximum vibration stress design method based on small sample test data as described in claim 1, characterized in that, After constructing the finite element model corresponding to each resonant frequency order, the following content is also included: In the finite element model, spring elements are used to simulate the contact between the blade crown and the tenon and mortise. The stiffness of the spring elements is continuously corrected until the deviation between the calculated resonance frequency of the finite element model and the measured resonance frequency of the dynamic stress measurement test is within the allowable error range.

3. The blade maximum vibration stress design method based on small sample test data as described in claim 1, characterized in that, After calculating the vibration localization factor for each resonant frequency order, the following is also included: Based on the vibration localization factor for each resonance frequency order, the test values ​​of different strain gauges at the same patch location are cleaned.

4. The blade maximum vibration stress design method based on small sample test data as described in claim 3, characterized in that, The process of cleaning the test values ​​of different strain gauges at the same patch location based on the vibration localization factor for each resonance frequency order includes the following: For different strain gauge test values ​​at the same patch location, the maximum and minimum values ​​of vibration stress measurement values ​​at each resonant frequency order are selected. If the ratio of the maximum value to the minimum value is greater than or equal to the preset ratio threshold, the maximum or minimum value is removed, and the ratio is recalculated until the ratio of the maximum value to the minimum value is less than the preset ratio threshold. The preset ratio threshold is obtained by multiplying the vibration localization factor of each resonant frequency order by a preset coefficient.

5. The blade maximum vibration stress design method based on small sample test data as described in claim 1, characterized in that, The following steps are included before calculating the average value of the converted maximum vibration stress at each resonant frequency order: Calculate the deviation between the equivalent maximum vibration stress at the location of the most sensitive patch and the location of the second most sensitive patch on the same blade. If the deviation is within a preset range, the equivalent maximum vibration stress at the location of the most sensitive patch is taken as the equivalent maximum vibration stress of the blade. If the deviation is not within the preset range, the average of the equivalent maximum vibration stress at the locations of the second most sensitive patch and the most sensitive patch is taken as the equivalent maximum vibration stress of the blade.

6. A blade maximum vibration stress design system based on small sample test data, characterized in that, include: The dynamic stress measurement result acquisition module is used to acquire the dynamic stress measurement test results and obtain the vibration stress measurement values ​​of all measuring points at each resonance frequency order. The finite element simulation calculation module is used to construct the finite element model corresponding to each resonance frequency order, adjust the parameters of each finite element model, take the finite element model with the largest vibration difference between different blades as the optimization model corresponding to each resonance frequency order, calculate the vibration localization factor of each resonance frequency order, and carry out simulation calculation based on the optimization model to obtain the sensitivity of each patch position under each resonance frequency order. The conversion maximum vibration stress calculation module is used to calculate the average conversion maximum vibration stress at each resonance frequency order based on the vibration stress measurement values ​​of all measuring points at each resonance frequency order and the sensitivity of each patch position corresponding to each resonance frequency order. The actual maximum vibration stress calculation module is used to calculate the actual maximum vibration stress at each resonance frequency order based on the vibration localization factor and the average value of the converted maximum vibration stress at each resonance frequency order. The vibration localization factor for each resonant frequency order is calculated based on the following formula: ； in, Indicates the first The vibration localization factor of the first resonant frequency. Indicates the first At the resonant frequency, the maximum vibration stress of the blade with the greatest vibration is... Indicates the first The maximum vibration stress of the blade with the least vibration at the first resonant frequency; The actual maximum vibration stress at each resonant frequency order is calculated based on the following formula: ； ； ； in, Indicates the first The actual maximum vibration stress at the first resonant frequency. Indicates the first The average maximum vibration stress converted from the first resonance frequency. Indicates a confidence level of p unilateral t Distribution range n Indicates the number of valid experimental data. Indicates the first The standard deviation of vibration stress at the first resonant frequency. Indicates the first The positive distribution of vibration stress at the first resonant frequency value, Indicates the first The negative of the vibration stress distribution at the first resonance frequency value, Indicates the first The vibration localization factor of the first resonant frequency.

7. An electronic device, characterized in that, The method includes a processor and a memory, wherein the memory stores a computer program, and the processor executes the steps of the method as described in any one of claims 1 to 5 by calling the computer program stored in the memory.

8. A computer-readable storage medium for storing a computer program for designing the maximum vibration stress of a blade based on small sample test data, characterized in that, The computer program, when run on a computer, performs the steps of the method as described in any one of claims 1 to 5.

Images