A method for obtaining the required strain gage placement for a gas turbine vane

Abstract

This application discloses a method for obtaining the required strain gauge placement positions for gas turbine blades, comprising: S1, obtaining initial parameters; S2, performing modal analysis based on the initial parameters, and outputting the modal analysis results, the modal analysis results including strain-related terms x for each mode of the blade. j Related terms y with characteristic frequencies j S3, Obtain modal analysis results and construct an initial response surface model; S4, Adjust the initial response surface model to obtain the final response surface model; S5, Calculate the response values ​​at each position of the blade based on the final response surface model; S6, Output the strain gauge placement position and direction according to the response values ​​at each position of the blade. The method for obtaining the required strain gauge placement position of a gas turbine blade proposed in this application comprehensively considers the modal analysis results and establishes an efficient and accurate response surface model. It is applicable to obtaining strain gauge positions in various scenarios, avoiding human randomness, and thus ensuring the accuracy of blade vibration stress monitoring.

Description

Technical Field

[0001] This application relates to the field of blade vibration testing technology, and in particular to a method for obtaining the required strain gauge placement position for gas turbine blades. Background Technology

[0002] Heavy-duty gas turbines are core equipment in the fields of power generation and drive, and strain gauges need to be attached to monitor vibration stress during the operation of heavy-duty gas turbines.

[0003] In existing technologies, the method for determining the location of strain gauges on blades typically involves using finite element analysis to perform blade modal analysis, and then manually calculating the node sensitivity based on the modal analysis results to select the strain gauge location.

[0004] Patent CN109582988A discloses a method for determining the location of strain gauges for vibration stress monitoring of aero-engine blades. Specifically, it includes establishing a finite element model of the blade, setting a set of nodes on the blade surface suitable for attaching strain gauges, performing modal analysis including element results using software to determine the critical modes, selecting the modes to be monitored, selecting nodes within the attachment node set, establishing a blade surface coordinate system, extracting node surface stress, and calculating node sensitivity, rotating the blade surface coordinate system to obtain the sensitivity of different nodes until the maximum sensitivity of the node is obtained, repeatedly performing the previous step to obtain the maximum sensitivity and angle of each node in the attachment node set for this mode, iteratively controlling the process to obtain the maximum sensitivity and angle of all attachable nodes for different modes, and comprehensively considering the maximum sensitivity of each node in the attachment node set for each mode to select the node for attachment. This patent uses finite element modal analysis to determine the attachment location, requiring designers to select based on the maximum sensitivity of each node. The selection results from individual designers are highly random and difficult to reproduce, and using only the maximum sensitivity as the sole selection criterion also has limitations.

[0005] Patent CN113569448A discloses a method for optimizing the structural parameters of a strain gauge sensitive grid based on response surface methodology. The method involves: first, determining the structural parameters and their ranges for the strain gauge sensitive grid, and then encoding and transforming them to obtain an experimental factor level table; determining the optimization index for the strain gauge sensitive grid structural parameters, namely the strain transfer error, and defining the calculation method for this error; designing a response surface experimental scheme using the Box-Behnken experimental design method, and conducting experiments based on the designed scheme; establishing a response surface model, using contour plots and response surface plots to determine the influence of structural parameters, and obtaining a regression equation; performing variance analysis, significance analysis, and error analysis to assess the fitting effect of the regression equation; and finally, finding the method that minimizes the strain transfer error of the strain gauge sensitive grid. This patent uses only the response surface methodology to confirm the relationship between the strain transfer error of the sensitive grid and the structural parameters. Summary of the Invention

[0006] The purpose of this application is to at least partially solve one of the aforementioned technical problems.

[0007] Therefore, the first objective of this invention is to propose a method for obtaining the required strain gauge placement positions for gas turbine blades. This method comprehensively considers the modal strain results and frequency analysis results from modal analysis, establishes a response surface model, and combines numerical simulation analysis results with the operator's past experience to obtain an efficient and accurate response surface model. This model can be applied to various scenarios for determining the required strain gauge positions for blades, avoiding the randomness of human operation and the limitations caused by using maximum sensitivity as the sole selection criterion. Ultimately, it obtains robust strain gauge positions for blades that can be directly applied in practice.

[0008] To achieve the above objectives, the first aspect of this application proposes a method for obtaining the required strain gauge placement position for a gas turbine blade, comprising:

[0009] Step S1: Obtain initial parameters;

[0010] Step S2: Perform modal analysis based on the initial parameters and output the modal analysis results, which include strain-related terms for each mode of the blade. Related terms of characteristic frequencies ;

[0011] Step S3: Obtain the modal analysis results and construct the initial response surface model;

[0012] Step S4: Adjust the initial response surface model to obtain the final response surface model;

[0013] Step S5: Calculate the response values ​​at each position of the blade based on the final response surface model;

[0014] Step S6: Output the strain gauge placement position and direction based on the response values ​​at each position of the blade.

[0015] Optionally, the initial parameters in step S1 include blade vibration frequency limiting parameters, blade size parameters, and strain gauge parameters.

[0016] Optionally, the blade vibration frequency limiting parameters in step S1 include the mode avoidance rate requirements for each order. And the maximum frequency of modal analysis.

[0017] Optionally, the strain gauge parameters in step S1 include strain gauge size parameters and the number of strain gauges.

[0018] Optionally, the blade size parameters in step S1 include the blade's geometric model, the maximum thickness of the blade's cross-section at each position, and the chord length of the blade's cross-section at each position.

[0019] Optionally, step S2 includes step S21, constructing a finite element model, inputting the blade size parameters into the finite element model for modal analysis, and outputting the equivalent strain of each mode at each position of the blade. Maximum equivalent strain of each modal order and the natural frequencies of each mode. .

[0020] Optionally, step S2 includes step S22, which is based on the equivalent strain of each mode at each position of the blade. and the maximum equivalent strain of each modal. Output strain correlation terms for each mode. Modal strain correlation terms Determined by the following formula:

[0021]

[0022] Optionally, step S2 includes step S23, based on the avoidance rate requirements of each modality. Natural frequencies of each mode Output characteristic frequency correlation term Characteristic frequency related terms Determined by the following formula:

[0023]

[0024] in, The input is the natural frequency of each mode. The closest excitation frequency.

[0025] Optionally, step S3 includes step S31, obtaining the initial correlation coefficient of the model. Initial correlation coefficient of the model Determined by the following formula:

[0026] ,

[0027] in, This is the blade surface position coefficient. This refers to the leaf region coefficient. Determined by the location of the blade. These are the modal order coefficients. It is determined by the modal order.

[0028] Optional, blade surface position coefficient It is determined by one or more factors, including the maximum thickness of the cross section at each position of the blade, the chord length of the cross section at each position of the blade, and the type of force on the surface where the blade is located at each position.

[0029] Optionally, step S3 includes step S32, based on the initial correlation coefficient of the model. Strain-related items and characteristic frequency related terms Construct an initial response surface model, which is as follows:

[0030]

[0031] in, is the response value, a is an undetermined coefficient, and n is determined by the maximum frequency of the modal analysis.

[0032] Optionally, step S4 includes step S41, attaching strain gauges, and the strain gauges output strain data at various locations on the blade. The strain gauge placement position is determined based on the initial response surface model.

[0033] Optionally, step S4 may also include step S42, constructing the response surface model determination coefficients R. 2 Response surface model, coefficient of determination R 2 for:

[0034]

[0035] in, For strain data The average value is k, where k is the minimum number of blade position points to adjust the initial response surface model.

[0036] Optionally, step S4 further includes step S43, based on the response surface model determination coefficient R... 2 To assess the reliability of the initial response surface model, if R 2 If the coefficient is greater than 0.9, the initial response surface model meets the requirements; otherwise, the coefficients to be determined (a) and the initial correlation coefficient of the model are compared using the least squares method. Adjustments were made to obtain the final response surface model.

[0037] Optionally, step S5 includes calculating the response value at each location of the blade based on the final response surface model, and outputting the blade location and strain gauge attachment direction with the maximum response value in each region.

[0038] Optionally, step S6 includes confirming the strain gauge placement position and strain gauge placement direction based on the strain gauge parameters, from high to low response values.

[0039] This application discloses a method for obtaining the required strain gauge placement position for gas turbine blades. The method involves acquiring initial parameters, performing modal analysis based on these parameters, outputting the modal analysis results, constructing an initial response surface model based on the results, adjusting the initial response surface model to obtain a final response surface model, calculating the response values ​​at various blade positions based on the final response surface model, and finally outputting the strain gauge placement position and direction based on the response values ​​at each blade position. This method comprehensively considers the modal strain and frequency analysis results from the modal analysis, combined with numerical analysis results and the designer's experience. Based on testing and adjustments, it obtains an efficient and accurate response surface model that can directly output the position coordinates and direction for strain gauge placement on various types of blades. This allows for direct practical application based on the results, avoiding the randomness of manually determined positions and errors in manual adjustments. This method enables the determination of the required strain gauge positions for heavy-duty gas turbine blades, thereby ensuring the accuracy of blade vibration stress monitoring.

[0040] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0041] The accompanying drawings, which form part of this specification, 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:

[0042] Figure 1 A flowchart of a method for obtaining the required strain gauge placement position for a gas turbine blade is provided according to one embodiment;

[0043] Figure 2 A flowchart of modal analysis for one embodiment is presented;

[0044] Figure 3 A flowchart for constructing an initial response surface model according to one embodiment is presented;

[0045] Figure 4 A flowchart for obtaining the final response surface model according to one embodiment is presented;

[0046] Figure 5 A flowchart of the response surface model establishment process in a specific embodiment is presented;

[0047] Figure 6 A structural diagram of the blade suction surface and pressure surface of a specific embodiment is provided;

[0048] Figure 7 A blade region distribution diagram of a specific embodiment is shown. Detailed Implementation

[0049] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0050] The present invention will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed by the present invention.

[0051] The following describes a method for obtaining the required strain gauge placement position for a gas turbine blade, according to an embodiment of this application, with reference to the accompanying drawings.

[0052] Figure 1 This is a flowchart illustrating a method for obtaining the required strain gauge placement position for a gas turbine blade according to an embodiment of this application, as shown below. Figure 1 As shown, the method includes the following steps:

[0053] S1, obtain initial parameters.

[0054] Specifically, the initial parameters include blade vibration frequency limiting parameters, blade size parameters, and strain gauge parameters.

[0055] Preferably, based on the operator's experience or historical data, and taking into account the actual operating conditions of the heavy-duty gas turbine, the modal excitation, and the data calculation efficiency, appropriate blade vibration frequency limiting parameters are selected as the frequency requirements. These blade vibration frequency limiting parameters include the mode avoidance rate requirements for each order. And the maximum frequency of modal analysis.

[0056] Specifically, the modal avoidance rate requirements for each order represent the designer's requirement for the minimum frequency difference between the natural frequency and the excitation frequency. Furthermore, the blade dimensions are input as geometric input, including the blade's geometric model, the maximum thickness of the blade's cross-section at each location, and the chord length of the blade's cross-section at each location. Modal analysis of the gas turbine blade is performed by setting the blade's geometric model, and the initial response surface parameters are obtained based on the maximum thickness and chord length of the blade's cross-section at each location.

[0057] In addition, the input strain gauge parameters are the strain gauge requirements, which include strain gauge size parameters and the number of strain gauges.

[0058] In this way, by integrating data from multiple dimensions such as space, quantity, and vibration frequency, the accuracy of the response surface model is improved, and the computational efficiency is also increased.

[0059] S2 performs modal analysis based on initial parameters and outputs the modal analysis results.

[0060] The modal analysis results may include strain-related terms for each mode of the blade. Related terms of characteristic frequencies , and The calculation method will be described in detail through the following specific steps.

[0061] Preferably, in this application, modal analysis results and frequency analysis results are obtained through finite element analysis. Alternatively, modal analysis can also be performed based on structural testing. The finite element analysis method will be further explained below:

[0062] S21: Construct a finite element model, input the blade size parameters into the finite element model for modal analysis, and output the equivalent strain of each modality at each position of the blade. Maximum equivalent strain of each modal order and the natural frequencies of each mode. .

[0063] S22: Equivalent effect strain based on modal variations at different positions of the blade and the maximum equivalent strain of each modal. Output strain correlation terms for each mode. Modal strain correlation terms Determined by the following formula:

[0064]

[0065] S23: Based on the avoidance rate requirements of each modal order Natural frequencies of each mode Output characteristic frequency correlation term Characteristic frequency related terms Determined by the following formula:

[0066]

[0067] in, The input is the natural frequency of each mode. The closest excitation frequency.

[0068] Through the above modal analysis process, based on the initial parameters, the modal strain results and frequency analysis results within the natural frequency range were obtained, laying the foundation for establishing a response surface model.

[0069] S3, obtain the modal analysis results and construct the initial response surface model.

[0070] Preferably, in this embodiment, the response surface model is constructed using a polynomial response surface as an example, such as... Figure 3 As shown, constructing the initial response surface model may further include the following steps:

[0071] S31: Obtain the initial correlation coefficient of the model Initial correlation coefficient of the model Determined by the following formula:

[0072] ,

[0073] in, This is the blade surface position coefficient. This refers to the leaf region coefficient. Determined by the location of the blade. These are the modal order coefficients. It is determined by the modal order.

[0074] Furthermore, the blade surface position coefficient The blade surface position coefficient is determined by one or more factors, including the maximum thickness of the blade cross-section at each location, the chord length of the blade cross-section at each location, and the type of force acting on the surface of the blade at each location. Preferably, in this application, the blade surface position coefficient... The initial response surface model is determined by three factors: the maximum thickness of the cross section at each position of the blade, the chord length of the cross section at each position of the blade, and the type of force on the surface at each position of the blade. This comprehensive consideration of the differences in structure and force at different positions of the blade allows the initial response surface model to incorporate design experience.

[0075] The blade surface was segmented at different locations, and the blade region coefficient at different locations was determined based on the strain gauge size and the actual operating conditions of the gas turbine blades. Furthermore, the initial response surface model incorporates design experience.

[0076] S32: Based on the initial correlation coefficient of the model Strain-related items and characteristic frequency related terms Construct an initial response surface model, which is as follows:

[0077]

[0078] in, The response value represents the reliability of the strain gauges at various points on the blade, and n is determined by the maximum frequency of the modal analysis.

[0079] Through the above process, an initial response surface model was established, taking into account the modal strain results and frequency analysis results of modal analysis. Based on the numerical simulation analysis results, an initial response surface model was obtained, which avoids the randomness of manually selecting the maximum sensitivity of each node and the possibility of errors in the calculation process. At the same time, it avoids the limitation of using the maximum sensitivity as the only selection, so that the calculation results are reproducible and robust, which can facilitate the confirmation of the appropriate position of the strain gauge required for heavy-duty gas turbine blades.

[0080] S4, adjust the initial response surface model to obtain the final response surface model.

[0081] like Figure 4 As shown, obtaining the final response surface model may further include the following steps:

[0082] S41: Install strain gauges; the strain gauges output strain data at various locations on the blade. The strain gauge placement position is determined based on the initial response surface model.

[0083] S42: Constructing the response surface model and determining the coefficients R. 2 Response surface model, coefficient of determination R 2 for:

[0084]

[0085] in, For strain data The average value is k, where k is the minimum number of blade position points to adjust the initial response surface model.

[0086] S43: Based on the coefficient of determination R in the response surface model 2 To assess the reliability of the initial response surface model, if R 2 If the coefficient is greater than 0.9, the initial response surface model meets the requirements; otherwise, the coefficients to be determined (a) and the initial correlation coefficient of the model are compared using the least squares method. Adjustments were made to obtain the final response surface model.

[0087] Through the above-mentioned final response surface model confirmation process, the initial response surface model is further adjusted based on the test to obtain a more appropriate model formula, thereby obtaining a definite response surface model. This makes the strain gauge positions required for heavy-duty gas turbine blades derived from the final response surface model more robust and enables more accurate monitoring of vibration stress in heavy-duty gas turbine blades.

[0088] S5, calculate the response values ​​at each position of the blade based on the final response surface model.

[0089] Specifically, based on the final response surface model, the response values ​​at each location of the blade are calculated, and the location of the blade with the maximum response value in each region and the strain gauge attachment direction are output.

[0090] Through the above calculation process, taking into account the modal strain analysis results and frequency analysis results, the response surface model is used to combine the numerical simulation analysis results with the operator's past experience. Based on the response surface model finally determined after S4 adjustment, multiple calculations are performed to obtain the required strain gauge positions for blades with stable response surface reliability. This can be used to solve the strain gauge problem for all types of blades without the need to manually adjust the strain gauges according to the blade form and type. This avoids the randomness and uncertainty of manually selecting the maximum sensitivity calculation, ensures the accuracy of the blade strain gauge installation position, and guarantees the stability of the vibration stress monitoring work of heavy-duty gas turbine blades.

[0091] S6 outputs the strain gauge placement position and direction based on the response values ​​at each position of the blade.

[0092] Specifically, based on the strain gauge parameters, the strain gauge placement position and orientation are determined from high to low response values. Since the response surface model is determined once the model is established, the three-dimensional coordinates of the selected strain gauge position and the strain gauge orientation can be obtained using any initial parameters. Therefore, the strain gauge placement is directly guided by the calculation results, eliminating the need for manual analysis and calculation, thus saving manpower.

[0093] This application discloses a method for obtaining the required strain gauge placement position for gas turbine blades. The method involves acquiring initial parameters, performing modal analysis based on these parameters, outputting the modal analysis results, constructing an initial response surface model based on the results, adjusting the initial response surface model to obtain a final response surface model, calculating the response values ​​at various blade positions based on the final response surface model, and finally outputting the strain gauge placement position and direction based on the response values ​​at each blade position. This method comprehensively considers the modal strain and frequency analysis results from the modal analysis, combined with numerical analysis results and the designer's experience. Based on testing and adjustments, it obtains an efficient and accurate response surface model that can directly output the position coordinates and direction for strain gauge placement on various types of blades. This allows for direct practical application based on the results, avoiding the randomness of manually determined positions and errors in manual adjustments. This method enables the determination of the required strain gauge positions for heavy-duty gas turbine blades, thereby ensuring the accuracy of blade vibration stress monitoring.

[0094] The following is a detailed description of the establishment of a response surface model using a specific embodiment. This embodiment uses a polynomial response surface as an example, which is only for illustration. The response surface model is as follows:

[0095]

[0096] in, The response values ​​of the response surface model represent the reliability of the strain gauges at various points on the blade. , For design parameter values, For modal strain related terms, The characteristic frequency correlation term; the undetermined coefficient 'a' and the initial correlation coefficient of the model. The undetermined coefficients of the response surface model are jointly determined and can be solved using the least squares method; l and m are the design parameter values. and The index; Modal order n is the design parameter and The number of modal frequencies is determined by the maximum value of the modal analysis frequency.

[0097] In addition, before establishing the response surface model, the design parameter values ​​need to be obtained through modal analysis. and The parameter value.

[0098] In addition, the response surface model will be tested after it is established, and applied to practice after the test results confirm its effectiveness.

[0099] like Figure 5 As shown, the establishment of a response surface model includes the following steps:

[0100] S501, Determine the input parameters for the response surface model.

[0101] Specifically, the coordinates are defined as Input parameters at the blade point :

[0102]

[0103] in, Modal strain related terms, where j is the modal order; For the blade point Equivalent strain of the j-th order characteristic frequency The maximum equivalent strain value of the j-th order characteristic frequency is obtained through modal analysis.

[0104] Define coordinates as Input parameters at the blade point :

[0105]

[0106] in, Modal strain related terms, where j is the modal order. Here, j represents the modal avoidance rate requirement for each mode, and j is the modal order. The j-th natural frequency is obtained through modal analysis; To be related to the j-th order natural frequency The closest excitation frequency.

[0107] S502, determine the undetermined coefficients of the response surface model.

[0108] Specifically, the response surface model consists of undetermined coefficients α and initial correlation coefficients. To be determined jointly.

[0109] The initial correlation coefficient for the model needs to be determined using both the input parameters and the initial test data.

[0110] ,

[0111] in, Determined by the geometric determinant of the leaf shape, such as Figure 6 As shown, the blade consists of a suction surface PS and a pressure surface SS. The position coefficients of different points on the blade surface are determined by the maximum blade thickness T and the chord length C, as shown in the following formula:

[0112] ,

[0113] The limiting values ​​are determined by the operator's past design experience. It is determined by the operator's past design experience, but in the absence of design experience, it can also be determined through the results of the first test.

[0114] Determined by the position of the blade point, such as Figure 7 As shown, the blade is divided into multiple regions according to the size of the strain gauge. The number of regions in the figure is only an example. The blade point position coefficients are different in each region, and these values ​​need to be determined through the results of the first test.

[0115] The values ​​are determined by the modal order; different vibration modes have different values. These values ​​are determined by the operator's past design experience, but in the absence of design experience, they can also be determined through the results of the first test.

[0116] S503, the index that determines the design parameters.

[0117] Specifically, design parameter values and The index is determined by the operator's past design experience, but in the absence of design experience, it can also be determined through the results of the first test.

[0118] S504, Evaluate the effectiveness of the response surface model.

[0119] Specifically, the coefficient of determination of the response surface model needs to be calculated to evaluate its effectiveness. At least one vibration test is performed based on the response surface model with determined parameter values. Strain gauges are then placed according to the locations determined by the initial response surface model. The test results of the strain gauges are processed to evaluate the effectiveness of the response surface model.

[0120] The coefficient of determination refers to the similarity between the calculated response surface methodology results and the test results. The formula is as follows:

[0121]

[0122] in, Let be the coefficient of determination for the response surface model, and k be the minimum number of leaf points used to determine the response surface model. Furthermore, if the obtained coefficient of determination is not less than 0.9, then the response surface model satisfies the validity of the evaluation.

[0123] S505, calculate the response value at each blade point.

[0124] Specifically, the input parameters are input into a response surface model that satisfies the S504 evaluation validity, the response value of each blade point is calculated, and considering the strain gauge size, only the location of the maximum response value of each partition and the strain gauge orientation at that point are output.

[0125] S506 outputs the strain gauge position and strain gauge placement direction.

[0126] Specifically, based on the input requirement for the number of strain gauge points, the strain gauge positions and corresponding strain gauge directions are selected from high to low.

[0127] This invention provides a reliable and effective method for determining strain gauge positions in the vibration and stress monitoring of heavy-duty gas turbines. It offers a complete response surface model establishment process, enabling accurate parameter setting and execution of testing and application operations. Furthermore, the output results of the response surface model can be directly applied to various types of blade patching practices without the need for human intervention in adjusting the actual application position of the blade patch. This avoids human error and the instability and randomness of the results' accuracy, providing an efficient and accurate model and method for determining the required strain gauge positions for blades.

[0128] The above is only one specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0129] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0130] It should be noted that, in the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

Claims

1. A method for obtaining the required strain gauge placement position for gas turbine blades, characterized in that, include: Step S1: Obtain initial parameters; The initial parameters in step S1 include blade vibration frequency limiting parameters, blade size parameters, and strain gauge parameters; the blade vibration frequency limiting parameters in step S1 include the mode avoidance rate requirements for each order. And the maximum modal analysis frequency; the strain gauge parameters mentioned in step S1 include strain gauge size parameters and the number of strain gauges; Step S2: Perform modal analysis based on the initial parameters and output the modal analysis results, which include strain correlation terms for each mode of the blade. Related terms of characteristic frequencies ; Step S2 includes step S21, constructing a finite element model, inputting the blade size parameters into the finite element model for modal analysis, and outputting the equivalent strain of each modality at each position of the blade. Maximum equivalent strain of each modal and the natural frequencies of each mode. Step S2 includes step S22, which involves assessing the equivalent strain of each mode at each position of the blade. and the maximum equivalent strain of each modal. Output strain correlation terms for each mode. The modal strain correlation terms of each order Determined by the following formula: Step S2 includes step S23, based on the avoidance rate requirements of each mode. The natural frequencies of each modal are described. Output the characteristic frequency correlation term The characteristic frequency correlation term Determined by the following formula: in, The input is related to the natural frequencies of each mode. The closest excitation frequency; Step S3: Obtain the modal analysis results and construct an initial response surface model; Step S3 includes Step S31: Obtain the initial correlation coefficient of the model. The initial correlation coefficient of the model Determined by the following formula: ， in, This is the blade surface position coefficient. This refers to the blade region coefficient. Determined by the location of the blade, These are the modal order coefficients, the modal order coefficients Determined by modal order; Step S3 includes step S32, based on the initial correlation coefficient of the model. The strain-related terms and the characteristic frequency related terms Construct the initial response surface model, which is as follows: Among them, the The response value is 'a', where 'a' is an undetermined coefficient, and 'n' is determined by the maximum value of the modal analysis frequency. Step S4: Adjust the initial response surface model to obtain the final response surface model; Step S4 includes step S41: attach the strain gauges, and the strain gauges output strain data at various positions of the blade. The strain gauge placement position is determined based on the initial response surface model; step S4 further includes step S42, constructing the response surface model determination coefficients R. 2 The response surface model's coefficient of determination R 2 for: Among them, the For the strain data The average value, where k is the minimum number of blade position points to adjust the initial response surface model; Step S4 further includes step S43, based on the determination coefficient R of the response surface model. 2 Evaluate the reliability of the initial response surface model. If R 2 If the initial response surface model is greater than 0.9, it meets the requirements; otherwise, the undetermined coefficient 'a' and the initial correlation coefficient of the model are evaluated using the least squares method. Adjustments were made to obtain the final response surface model; Step S5: Calculate the response values ​​at each position of the blade based on the final response surface model; Step S6: Output the strain gauge placement position and placement direction based on the response values ​​at each position of the blade.

2. The method for obtaining the required strain gauge placement position for gas turbine blades according to claim 1, characterized in that, The blade size parameters mentioned in step S1 include the geometric model of the blade, the maximum thickness of the cross section at each position of the blade, and the chord length of the cross section at each position of the blade.

3. The method for obtaining the required strain gauge placement position for gas turbine blades according to claim 1, characterized in that, The blade surface position coefficient It is determined by one or more of the following factors: the maximum thickness of the cross section at each position of the blade, the chord length of the cross section at each position of the blade, and the type of force on the surface where the blade is located at each position.

4. The method for obtaining the required strain gauge placement position for a gas turbine blade according to any one of claims 1-3, characterized in that, Step S5 includes calculating the response value at each position of the blade based on the final response surface model, and outputting the position of the blade with the maximum response value in each region and the strain gauge attachment direction.

5. The method for obtaining the required strain gauge placement position for a gas turbine blade according to any one of claims 1-3, characterized in that, Step S6 includes confirming the strain gauge placement position and strain gauge placement direction based on the strain gauge parameters, from high to low response values.

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