Component fatigue weak area simulation test piece design method and device, equipment, medium

Abstract

The application provides a component fatigue weak area simulation test piece design method and device, equipment and medium, and belongs to the technical field of aero-engines and gas turbines. The method comprises the following steps: acquiring a characteristic parameter corresponding to a fatigue weak area of a target turbine component; acquiring a geometric configuration of a simulation test piece and a round hole diameter of the geometric configuration; determining a target parameter of the geometric configuration according to the characteristic parameter, the geometric configuration and the round hole diameter; acquiring a peak stress corresponding to the fatigue weak area of the target turbine component, and determining a required loading load of the geometric configuration according to the peak stress and the target parameter; and generating a design file of the simulation test piece according to the target parameter and the loading load. The component fatigue weak area simulation test piece design method and device, equipment and medium provided by the application can reduce the difference between the fatigue damage mechanism of the simulation test piece and the real component.

Description

Technical Field

[0001] This application belongs to the field of aero-engine and gas turbine technology, and more specifically, it relates to a design method, device, equipment and medium for simulating fatigue weak zone test specimens of components. Background Technology

[0002] Turbine components (such as turbine disks and turbine blades) are subjected to complex cyclic loads under high-temperature and high-speed conditions. Geometric discontinuities such as tenons, cooling holes, and chamfers often become fatigue weak points, affecting the service life and safety of turbine components. In order to evaluate the fatigue performance of materials and predict the service life of real components under laboratory conditions, it is usually necessary to design standard simulated specimens with equivalent mechanical characteristics to the weak points of real components. The fatigue behavior of real components is then extrapolated from the fatigue test results of the simulated specimens.

[0003] Currently, common simulation specimen design methods primarily rely on geometric equivalence based on elastic stress concentration factors. For example, by adjusting the ratio of the diameter to the width of the circular hole in a flat plate specimen, the theoretical stress concentration factor at the hole edge is made consistent with that of the weak zone in a real component. However, the weak zone of an actual turbine component not only possesses a specific stress concentration factor, but the stress gradient distribution along the depth direction and the triaxiality factor of the stress state also play a decisive role in the initiation and propagation of fatigue cracks. Methods based on geometric equivalence using elastic stress concentration factors often only consider the matching of stress concentration factors, neglecting the influence of stress gradient distribution and triaxiality factor, leading to significant differences in the fatigue damage mechanism between the designed simulation specimen and the real component. Summary of the Invention

[0004] This application provides a design method, device, equipment, and medium for simulating fatigue weak zones of components. It solves the technical problem that existing simulation specimen designs cannot simultaneously match multiple key stress field characteristic parameters of fatigue weak zones in real components. It achieves the goal of having an equivalent fatigue damage mechanical environment between the simulation specimen and the real component, and reduces the difference between the simulation specimen and the real component in terms of fatigue damage mechanism.

[0005] According to one aspect of the embodiments of this application, a method for designing a simulated specimen for fatigue weak zones of a component is provided, comprising: Obtain the characteristic parameters corresponding to the fatigue weak areas of the target turbine component. The characteristic parameters include the target elastic stress concentration factor, stress gradient distribution curve, and triaxiality factor. Obtain the geometric configuration of the simulated specimen and the diameter of the circular hole in the geometric configuration; Based on the characteristic parameters, geometric configuration, and diameter of the circular hole, determine the target parameters of the geometric configuration, including the width, chamfer radius, and thickness of the geometric configuration; Obtain the peak stress corresponding to the fatigue weak area of ​​the target turbine component, and determine the loading load required for the geometric configuration based on the peak stress and target parameters; Based on the target parameters and the applied load, design files for the simulated specimen are generated.

[0006] According to one aspect of the embodiments of this application, a device for designing simulated fatigue weak zones of components is provided, comprising: The parameter acquisition module is used to acquire the characteristic parameters corresponding to the fatigue weak areas of the target turbine component. The characteristic parameters include the target elastic stress concentration factor, stress gradient distribution curve, and triaxiality factor. The geometry acquisition module is used to acquire the geometry of the simulated specimen and the diameter of the circular hole in the geometry. The target parameter acquisition module is used to determine the target parameters of the geometric configuration based on the feature parameters, geometric configuration, and diameter of the circular hole. The target parameters include the width, chamfer radius, and thickness of the geometric configuration. The load acquisition module is used to acquire the peak stress corresponding to the fatigue weak area of ​​the target turbine component, and determine the loading load required for the geometric configuration based on the peak stress and target parameters. The design file generation module is used to generate design files for the simulated specimen based on the target parameters and the applied load.

[0007] According to one aspect of the embodiments of this application, an electronic device is provided, the electronic device including a processor and a memory, the memory storing a computer program, the computer program being loaded and executed by the processor to implement the above-described method for designing simulated specimens of fatigue weak zones of components.

[0008] According to one aspect of the embodiments of this application, the computer program product includes a computer program stored in a computer-readable storage medium. A processor of an electronic device reads the computer program from the computer-readable storage medium and executes the computer program, causing the electronic device to perform the aforementioned method for designing simulated fatigue weak zones of components.

[0009] The technical solutions provided in this application embodiment may have the following beneficial effects: This application's embodiments overcome the shortcomings of only matching the elastic stress concentration factor while ignoring the stress gradient and triaxiality factor by simultaneously acquiring three characteristic parameters: the elastic stress concentration factor, the stress gradient distribution curve, and the triaxiality factor, in the fatigue weak zone of the target turbine component. Based on these parameters, the width, chamfer radius, thickness, and loading load of the simulated specimen are determined. Specifically, in this application's embodiments, matching the elastic stress concentration factor ensures consistent peak stress amplification effects at the hole edge; matching the stress gradient distribution ensures the same stress attenuation law along the depth direction, guaranteeing the equivalence of the driving force field for fatigue crack initiation and early propagation; and matching the triaxiality factor reproduces the multiaxial stress constraint state, avoiding plane stress / plane strain distortion caused by improper thickness. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 A flowchart illustrating the design method for simulating fatigue weak zones of components provided in this application embodiment; Figure 2 A schematic diagram of a rectangular plate with a circular hole in the center, used as a simulated specimen, is provided for an embodiment of this application. Figure 3 A schematic diagram comparing the radial stress gradient at the edge of the hole in the simulated specimen provided in the embodiments of this application; Figure 4 A schematic diagram of the mapping curve between triaxiality factor and thickness-to-diameter ratio provided for embodiments of this application; Figure 5 A structural block diagram of the component fatigue weak zone simulation specimen design device provided in the embodiments of this application; Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0013] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0014] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0015] Figure 1 This is a flowchart of a method for designing simulated fatigue weak zones of components according to an embodiment of this application. The method is executed by an electronic device and may include: S101: Obtain the characteristic parameters corresponding to the fatigue weak areas of the target turbine component.

[0016] In this embodiment, the characteristic parameters include the target elastic stress concentration factor, the stress gradient distribution curve, and the triaxiality factor.

[0017] In this embodiment, the target elastic stress concentration factor refers to the ratio of the maximum principal stress in the fatigue weak region of the component to the nominal stress far away from that region. This target elastic stress concentration factor reflects the degree of stress amplification due to geometric discontinuities and typically ranges from 1.5 to 5.0. The stress gradient distribution curve refers to the variation of stress with distance from the fatigue weak point (e.g., the maximum stress point at the edge of a hole) along the direction of the maximum principal stress (usually radial or perpendicular to the direction of geometric discontinuities). This stress gradient distribution curve is used to characterize the degree of localization of the stress field, and typically the stress drops sharply within the range of 0 to 2 mm. The triaxiality factor refers to the ratio of hydrostatic stress to equivalent stress. This triaxiality factor can quantitatively characterize the multiaxial stress constraint state of a material point.

[0018] In this embodiment, the target turbine component to be analyzed (e.g., the flange bolt hole area of ​​a high-pressure turbine disk) is selected. A three-dimensional solid finite element model of the component is established using finite element software (e.g., ANSYS), and realistic boundary conditions (e.g., rotational speed, temperature field, and assembly preload) are applied to obtain accurate stress distribution results. This model can accurately reflect the geometry of the component, including detailed features such as hole chamfers and transition fillets.

[0019] This embodiment applies corresponding loads and boundary conditions based on the typical operating conditions of the component in actual service (e.g., maximum takeoff state, maximum cruise state, etc.). For example, taking a turbine disk, centrifugal loads, thermal loads, or mechanical loads are typically applied. For centrifugal loads, an angular velocity field corresponding to the maximum rotational speed is applied, and material density is assigned to calculate the centrifugal force. For thermal loads, a temperature field distribution obtained from thermal analysis is applied as a predefined field. For mechanical loads, if assembly loads such as bolt preload exist, pressure or preload is applied to the corresponding surfaces.

[0020] From the analysis results of the finite element model, the core parameters corresponding to the fatigue weak areas of the target turbine component under analysis are extracted, including nominal stress, target elastic stress concentration factor, stress gradient distribution curve, triaxiality factor, and local peak stress. The nominal stress is calculated by selecting several nodes in a region far from the bore edge with uniform stress distribution (e.g., a non-perforated section of the disk rim) and using this average stress as the nominal stress. The target elastic stress concentration factor can be obtained as follows: ,in, Indicates the target elastic stress concentration factor. This indicates the maximum stress in the fatigue-weak region. This represents the nominal stress. The stress gradient distribution curve can be obtained as follows: starting from the fatigue weak point (the node with the maximum stress at the hole edge), select a series of nodes along the direction of maximum stress (e.g., from the hole radially towards the center of the disk), extract the stress value of each node, generate multiple discrete data points, and then obtain a continuous distribution curve (stress decay curve σ=f(x)) by curve fitting of these discrete data points. The triaxiality factor can be obtained as follows: ,in, Indicates the triaxiality factor. This represents hydrostatic stress, which can be extracted from fatigue weak points. It represents the equivalent stress.

[0021] S102: Obtain the geometric configuration of the simulated specimen and the diameter of the circular hole in the geometric configuration.

[0022] In this embodiment, the geometric configuration of the simulated specimen refers to the shape and structural form of the specimen used to reproduce the local mechanical state of the component. The geometric configuration selected in this embodiment is a rectangular flat plate with a central hole (i.e., a "central hole plate"), such as... Figure 2As shown, the plate width W can be 20.46 mm, the diameter d of the circular hole (center hole diameter) can be 8 mm, the thickness B can be 4 mm, the chamfer radius r can be 3 mm, and the hole edge distance (distance from the edge of the center hole to the side of the plate) can be 6.23 mm. This rectangular plate generates a stable stress concentration zone at the hole edge under uniaxial loading, facilitating the study of fatigue crack initiation. Furthermore, it is simple to manufacture, requiring only conventional processes such as cutting, drilling, and chamfering, making it suitable for plate fixtures in general-purpose electro-hydraulic servo fatigue testing machines.

[0023] The diameter of the circular hole refers to the size of the central circular hole in the plate. This diameter can be determined based on the clamping capacity of the testing machine and the size of the standard cutting tool. The range of the circular hole diameter is usually 3mm-10mm.

[0024] In this embodiment, a rectangular plate with a central hole is selected as the geometric configuration of the simulated specimen. The aspect ratio of this geometric configuration (the ratio of the length parallel to the loading direction to the width of the plate) must ensure that there is sufficient force transmission distance between the clamping end of the specimen and the dangerous section at the edge of the hole during loading. Typically, the total length of the specimen is designed to be 3 to 5 times the width of the plate to avoid the end effect affecting the stress distribution at the edge of the hole.

[0025] In this embodiment, the diameter of the circular hole can be obtained in the following way: If the geometric dimensions (e.g., bolt hole diameter) of the fatigue-weak region of the target turbine component are known, then that diameter can be used as the initial circular hole diameter.

[0026] If the geometric dimensions of the fatigue-weak region of the target turbine component are unknown and there is no clear reference, then a commonly used value, such as 5 mm, is selected from the range of the above-mentioned hole diameters.

[0027] As can be seen from the above, this embodiment reduces the complexity of components to a standardized two-dimensional plate-like structure, avoiding the blindness and high cost of full-size component testing. The selection of the circular hole diameter in this embodiment fully considers standard tool sizes and common machining capabilities, enabling the designed simulated specimens to be mass-produced using conventional processes, reducing specimen costs and making them suitable for engineering application.

[0028] S103: Determine the target parameters of the geometric configuration based on the characteristic parameters, geometric configuration, and diameter of the circular hole.

[0029] In this embodiment, the target parameters include the width, chamfer radius, and thickness of the geometric configuration.

[0030] In one embodiment of this application, the method for determining the width of the geometric configuration includes: Obtain the theoretical elastic stress concentration factor for the geometric configuration; Based on the theoretical elastic stress concentration factor and the diameter of the circular hole, and using the formula for the theoretical stress concentration factor of the central hole plate, the width of the geometric configuration is determined. The formula for the theoretical stress concentration factor of the central hole plate is as follows: ,in, This represents the theoretical elastic stress concentration factor. The diameter of the circular hole representing the geometric configuration. Indicates the width of the geometric configuration.

[0031] In this embodiment, the theoretical elastic stress concentration factor refers to the ratio of the maximum stress at the hole edge to the nominal stress away from the hole edge, calculated based on linear elasticity theory under a certain geometric configuration. The linear elasticity theory used in this embodiment is a classical theory in solid mechanics, assuming that the stress-strain relationship of the material obeys Hooke's law and that the deformation is reversible. It is widely used in the analytical calculation of stress concentration factors, and those skilled in the art can calculate the theoretical elastic stress concentration factor for a given geometric configuration based on this theory.

[0032] In order to further align the stress amplification effect of the hole edge of the geometric configuration with the stress amplification effect of the fatigue weak zone of the real turbine component, this embodiment uses the target elastic stress concentration factor as the theoretical elastic stress concentration factor of the geometric configuration.

[0033] In this embodiment, the theoretical elastic stress concentration factor formula for the central hole plate is a function of the plate width. This theoretical stress concentration factor formula for the central hole plate can be: ,in, This represents the theoretical elastic stress concentration factor. The diameter of the circular hole representing the geometric configuration. This indicates the width of the geometric configuration, in mm.

[0034] In this embodiment, the target elastic stress concentration factor is substituted into the theoretical stress concentration factor formula for the central orifice plate to obtain the following result. The value of is used to obtain the plate width of the geometric configuration.

[0035] To further improve the accuracy of plate width calculation, this embodiment substitutes the plate width obtained above into the theoretical elastic stress concentration factor term in the verification formula to calculate the first relative error between the theoretical elastic stress concentration factor and the target elastic stress concentration factor. The calculation method for this first relative error can be as follows: If the relative error is less than a preset error threshold (e.g., 5%), the value of the board width is determined to be valid. If the first relative error is not less than the preset error threshold, the board width of the geometric configuration is finely adjusted according to the preset step size, and a new first relative error is recalculated. If the new first relative error is still not less than the preset error threshold, the board width is adjusted until the first relative error is less than the preset error threshold.

[0036] In one embodiment of this application, the method for determining the chamfer radius of the geometric configuration includes: Set the initial chamfer radius; Adjust the initial chamfer radius according to the preset step size, calculate the error between the actual stress concentration factor and the target elastic stress concentration factor of the geometric configuration after each adjustment, and the radial stress gradient distribution curve of the geometric configuration. The chamfer radius of the geometric configuration is the adjusted chamfer radius where the error is within the preset error range and the relative error between the radial stress gradient distribution curve and the stress gradient distribution curve is less than or equal to the preset curve error.

[0037] In this embodiment, a two-dimensional plane stress model is established based on the determined basic geometric configuration of the simulated specimen (a rectangular plate with a central circular hole), the diameter of the circular hole, and the width of the plate. (This model takes a unit thickness in the thickness direction and sets plane stress elements.) This two-dimensional plane stress model can ignore the constraint changes in the thickness direction and can accurately reflect the in-plane stress concentration and radial stress gradient at the edge of the hole.

[0038] In this embodiment, the initial chamfer radius is set according to the diameter of the circular hole. For example, setting The actual stress concentration factor of the simulated specimen is determined based on the initial chamfer radius and the maximum principal stress at the hole edge.

[0039] In this embodiment, stress values ​​at a series of points radially outward from the hole edge are extracted, and a radial stress gradient distribution curve is plotted. The second relative error is determined based on the actual stress concentration factor and the target elastic stress concentration factor. .

[0040] In this embodiment, if the second relative error is not within the preset error range, or if the relative error between the radial stress gradient distribution curve and the stress gradient distribution curve is greater than the preset curve error, the initial chamfer radius is gradually increased or decreased by a preset step size (e.g., 0.05 mm). Generally, increasing the initial chamfer radius decreases the actual stress concentration factor; decreasing the initial chamfer radius increases the actual stress concentration factor. In this embodiment, after each adjustment, a new finite element analysis is performed to calculate the new actual stress concentration factor and the radial stress gradient curve. The second relative error after each adjustment and the relative error between the radial stress gradient curve and the target curve are recorded (e.g., the average value of the relative errors of stress values ​​at corresponding points within a radial distance range of 0–2 mm).

[0041] If the second relative error of the adjusted chamfer radius is within the preset error range, and the relative error between the radial stress gradient distribution curve and the stress gradient distribution curve is less than or equal to the preset curve error, then the iteration stops, and the current chamfer radius is used as the chamfer radius of the finally selected geometry. Figure 3 The diagram shown is a comparison of the radial stress gradient at the edge of the hole in the simulated specimen provided in the embodiment of this application.

[0042] If the above conditions cannot be met simultaneously, the chamfer radius can be fine-tuned to optimize the matching degree of the gradient curve, provided that the second relative error condition is met.

[0043] It should be noted that determining the chamfer radius mainly focuses on the in-plane stress gradient, and a two-dimensional plane stress model is sufficient to meet the accuracy requirements; however, the subsequent thickness determination involves the constraint effect in the thickness direction, requiring a three-dimensional solid model (three-dimensional flat plate finite element model). This embodiment adopts a step-by-step modeling strategy to balance computational efficiency and accuracy.

[0044] As can be seen from the above, this embodiment, by introducing an initial chamfer radius, a preset step size, a preset error range, and a preset curve error, achieves precise matching between the simulated specimen's local hole edge and the fatigue weak area of ​​the real component in terms of two key mechanical characteristics: the elastic stress concentration factor and the radial stress gradient distribution. This improves the stress field fidelity of the simulated specimen. This embodiment also introduces a stress gradient curve matching criterion, ensuring that the driving force field during the fatigue crack initiation and early propagation stages is consistent with that of the real component. This avoids complex multivariate simultaneous optimization, reduces design difficulty and computational cost, and has the advantages of simple operation, reliable convergence, and strong engineering applicability.

[0045] In one embodiment of this application, the method for determining the thickness of the geometric configuration includes: Based on the triaxiality factor and the diameter of the circular hole, and through parametric finite element analysis, the mapping relationship between the thickness of the geometric configuration and the triaxiality factor is determined. The target thickness-to-diameter ratio is determined based on the mapping relationship and the triaxiality factor; The thickness of the geometric configuration is determined based on the target thickness-to-diameter ratio and the diameter of the circular hole. The thickness-to-diameter ratio is the ratio of the thickness of the geometric configuration to the diameter of the circular hole.

[0046] In this embodiment, to determine the thickness B of the simulated specimen so that its triaxiality factor at the center of the hole edge is consistent with the triaxiality factor of the fatigue-weak region of the target component, this embodiment employs a parametric finite element analysis method, specifically including the following steps: Step 1: Obtain the initial chamfer radius, and construct a three-dimensional finite element model of a flat plate with a central circular hole based on the diameter of the circular hole, the width of the plate, and the initial chamfer radius. The chamfer feature is retained in the three-dimensional finite element model of the flat plate, and the elastic constitutive parameters of the material (such as Young's modulus and Poisson's ratio) are set. The diameter of the circular hole is set to 6 mm, the width of the plate is set to 24 mm, and the initial chamfer radius is set to 0.8 mm.

[0047] Step 2: Keep the diameter of the circular hole, the width of the plate, and the initial chamfer radius unchanged in the 3D plate finite element model, only changing the thickness B of the plate. In this embodiment, to study the influence of thickness on the constraint state, multiple different thickness-to-diameter ratios B / d are selected for modeling and analysis, using the diameter of the circular hole as a reference, such as B / d = 0.5, 0.8, 1.0, 1.2, 1.5, 2.0, etc. A unit axial tensile load (or other reference load) is applied to the model under each thickness parameter, and linear elastic or elastoplastic finite element calculations are performed to obtain the stress distribution and the triaxiality factor calculation results. After the calculation is completed, the hydrostatic stress and equivalent stress at the location of the maximum principal stress are extracted to determine the corresponding triaxiality factor value. The linear elastic finite element calculation in this embodiment is suitable for small deformation problems where the material has not yet reached yield, and has high computational efficiency; the elastoplastic finite element calculation further considers the yielding and hardening behavior of the material, and is suitable for scenarios that require accurate capture of local plastic deformation. Whether to use linear elastic finite element calculation or elastoplastic finite element calculation in this embodiment can be selected according to the actual scenario and specific requirements.

[0048] Step 3: Organize the triaxiality factor values ​​calculated under different B / d values, and plot the mapping curve of the triaxiality factor value as a function of B / d, such as... Figure 4 As shown in the mapping curve, when B / d is less than a preset thickness-to-diameter ratio threshold (e.g., 1.0), the triaxiality factor value is low and increases significantly with increasing thickness; when B / d is not less than the preset thickness-to-diameter ratio threshold, the growth rate of the triaxiality factor value slows down and gradually approaches saturation, indicating that the material point has entered a highly constrained plane strain state. Based on the target triaxiality factor extracted from the real component, the corresponding target thickness-to-diameter ratio is found on the mapping curve. If the value of the triaxiality factor is located in the plateau region of the mapping curve, any stable target thickness-to-diameter ratio within that plateau region is selected; if the value of the triaxiality factor is located in the rising segment of the mapping curve, the target thickness-to-diameter ratio can be determined by interpolation.

[0049] Step 4: Based on the determined diameter of the circular hole and the target thickness-to-diameter ratio, calculate the thickness B of the simulated specimen using the following formula: ,in, Indicates the target thickness-to-diameter ratio. This indicates the diameter of the circular hole.

[0050] As can be seen from the above, this embodiment establishes a quantitative mapping relationship between the thickness of the simulated specimen and the triaxiality factor through parametric finite element analysis, achieving accurate reproduction of the multiaxial constraint state of the fatigue weak zone of the component. Compared with the traditional method of only matching the elastic stress concentration factor, this embodiment overcomes the technical defect that the specimen is in a plane stress state due to insufficient thickness, leading to distortion of the fatigue damage mechanism. By reasonably setting the thickness-to-diameter ratio and optimizing its value range, it ensures both sufficient saturation and mechanical equivalence of the constraint state, while avoiding material waste and experimental loading difficulties caused by excessive specimen thickness, thus improving the physical realism and engineering practicality of the simulated specimen design.

[0051] In one embodiment of this application, after determining the target parameters of the geometric configuration, the method further includes: Based on the width, diameter of the circular hole, and thickness of the geometric configuration, the net cross-sectional area of ​​the geometric configuration is calculated using the net cross-sectional area calculation formula. The net cross-sectional area calculation formula is as follows: ,in, Represents the net cross-sectional area of ​​the geometric configuration. Indicates the diameter of the circular hole. The width of the plate representing the geometric configuration. Indicates the thickness of the geometric configuration.

[0052] In this embodiment, the net cross-sectional area refers to the effective load-bearing area remaining on the critical section after deducting the area occupied by the circular hole. The critical section refers to the cross section in the simulated specimen that bears the maximum nominal stress.

[0053] In this embodiment, the net cross-sectional area of ​​the geometric configuration is determined according to the formula for net cross-sectional area: ,in, Represents the net cross-sectional area of ​​the geometric configuration. Indicates the diameter of the circular hole. The width of the plate representing the geometric configuration. Indicates the thickness of the geometric configuration. This indicates the width of the net cross-section.

[0054] S104: Obtain the peak stress corresponding to the fatigue weak area of ​​the target turbine component, and determine the loading load required for the geometric configuration based on the peak stress and target parameters.

[0055] In this embodiment, the peak stress corresponding to the fatigue weak area of ​​the target turbine component is the local peak stress obtained above.

[0056] In one embodiment of this application, determining the required loading load for the geometry includes: Obtain the actual stress concentration factor corresponding to the chamfer radius; Determine the stress corresponding to the net cross-sectional area based on the peak stress and the actual stress concentration factor; The product of stress and net cross-sectional area of ​​the geometry is used as the load required for the geometry.

[0057] In this embodiment, the actual stress concentration factor corresponding to the chamfer radius is obtained. If multiple adjusted chamfer radii satisfy the condition that the second relative error is within a preset error range, and the relative error between the radial stress gradient distribution curve and the stress gradient distribution curve is less than or equal to the preset curve error, then the actual stress concentration factor corresponding to the chamfer radius that is closest to the target elastic stress concentration factor and has the smallest relative error between the radial stress gradient distribution curve and the stress gradient distribution curve is selected. In this embodiment, the relative error can be calculated as follows: at least 20 sampling points are uniformly taken within a radial distance of 0~2mm, the relative error of the stress value at each point is calculated, and the arithmetic mean is taken as the curve relative error.

[0058] This embodiment is based on the local peak stress and the actual stress concentration factor, and uses the formula for calculating the nominal stress of the net section. Calculate the nominal stress of the net cross section, where, This represents the nominal stress of the net cross-section (the stress corresponding to the net cross-sectional area). This nominal stress of the net cross-section characterizes the average stress that the critical section of the simulated specimen must withstand in order to produce the same local peak stress at the edge of the hole as the target component.

[0059] The product of the nominal stress and the net cross-sectional area is used as the required loading load for this geometry. In this embodiment, the magnitude of the loading load is compared with the rated load capacity of the selected fatigue testing machine. Typically, the required loading load is required to be no more than 90% of the maximum capacity of the testing machine and no less than 10 times its minimum resolvable load to ensure control accuracy. If the required loading load exceeds the range, the process returns to step S102 to readjust the diameter of the circular hole or to step S103 to readjust the thickness.

[0060] After determining the required loading load, this embodiment generates a complete cyclic loading command based on the loading load and the expected test frequency (e.g., 20Hz) for use by the fatigue testing machine.

[0061] In one embodiment of this application, after determining the required load for the geometry, at least one of the following is further performed: The geometry is subjected to stress annealing. Fatigue tests are conducted on the geometry based on the applied load to obtain the fatigue test results of the geometry, and the residual stress field on the edge surface of the circular hole of the geometry is obtained. The fatigue test results are then corrected based on the residual stress field to obtain the corrected fatigue test results.

[0062] In this embodiment, the machined simulated specimen undergoes stress-relief annealing. Specifically, the annealing temperature is selected based on the material of the simulated specimen (e.g., a high-temperature alloy) (typically 0.3 to 0.5 times the absolute melting point of the material, or a value recommended in a material handbook). The specimen is heated to this temperature in a vacuum or inert gas protected furnace and held for a sufficient time (determined based on the specimen thickness, generally several hours), and then slowly cooled to room temperature in the furnace. This annealing treatment eliminates residual stress introduced by machining processes such as drilling and chamfering, making the initial stress state of the specimen close to the designed stress-free state.

[0063] In this embodiment, fatigue testing is conducted on the geometric configuration based on the applied load, specifically including: Non-destructive testing methods such as X-ray diffraction were used to measure residual stress at multiple key locations (e.g., maximum stress points, along the hole perimeter, and radially) on the surface of the simulated specimen. Fatigue tests were then conducted on the simulated specimen based on the applied load (and stress ratio) to obtain the initial fatigue life. The residual stress was used as the average stress, and the stress field generated by the applied load was superimposed or corrected based on material fatigue theory (e.g., Goodman correction) or finite element analysis. The equivalent fatigue driving force was recalculated, resulting in corrected fatigue test results. This correction process eliminated the interference of machining residual stress, allowing the test data to more accurately reflect the fatigue performance under the designed mechanical state.

[0064] S105: Generate the design file for the simulated specimen based on the target parameters and the applied load.

[0065] In this embodiment, engineering drawings and enlarged views are drawn based on the acquired target parameters, and a three-dimensional solid model of the simulated specimen is established based on the target parameters, and an IGES format file is exported; the loading load, stress ratio, frequency, etc. are compiled into an instruction table; the above engineering drawings, three-dimensional solid model and instruction table are packaged into a design file for the simulated specimen.

[0066] For example, a simulated specimen design is used to simulate the fatigue weak zone of the turbine disk bolt holes.

[0067] This embodiment uses ABAQUS finite element software to establish a three-dimensional elastoplastic model of the turbine disk. The mechanical properties of FGH96 alloy at 650°C are input as material properties. The applied load condition is the engine's maximum takeoff (MTO) state: the engine speed is set to 15200 rpm, a corresponding centrifugal force is applied at the wheel center, and a pressure load simulating bolt preload is applied at the wheel rim bolt holes. Considering the temperature field, the disk's temperature field distribution is applied as a predefined field.

[0068] After solving the model, the data of the node with the maximum stress at the edge of the critical bolt hole of the wheel flange (i.e. the fatigue weak point) were extracted, including: the local peak stress (maximum principal stress) is 950 MPa, the target elastic stress concentration factor Kt=950 / 380 =2.5, the stress gradient is within 0.5 mm, the stress rapidly decreases from 950 MPa to about 600 MPa, and the triaxiality factor is 0.78, which indicates that the point is in a high-constraint state close to plane strain.

[0069] In this embodiment, a rectangular plate specimen with a central circular hole is selected as the simulated specimen. Taking into account the width of the commonly used testing machine chuck (usually ≥30mm) and the standard drill bit size, the initial diameter of the circular hole is preset to 6mm.

[0070] In this embodiment, the plate width is determined as follows: the target elastic stress concentration factor is substituted into the formula for the theoretical stress concentration factor of the central hole plate, and the plate width is solved by numerical iteration. When the plate width is 24mm, the first relative error between the theoretical elastic stress concentration factor and the target elastic stress concentration factor is 0.4%, which meets the requirement for the first relative error. Therefore, the plate width is determined to be 24mm.

[0071] In this embodiment, the chamfer radius is determined as follows: An initial chamfer radius of 0.8 mm is set (typically 0.1d to 0.15d). A three-dimensional finite element model of the specimen containing this chamfer is established. Elastic analysis is performed by applying a unit tensile stress, extracting the maximum stress at the hole edge, and calculating the actual elastic stress concentration factor to be 2.52, with an error of 0.8% compared to the target elastic stress concentration factor of 2.5. The radial stress gradient curve at the hole edge of the specimen is extracted and compared with the curve extracted from the turbine disk model. By fine-tuning the chamfer radius value (e.g., between 0.7 and 0.9 mm), the two curves are made to overlap as much as possible within the range of 0-1.5 mm. The chamfer radius with the optimal overlap (minimum relative error) is taken as the chamfer radius of the geometric configuration.

[0072] In this embodiment, the thickness is determined as follows: The target triaxiality factor is 0.78. For a specimen model with a circular hole diameter of 6mm, a width of 24mm, and a chamfer radius of 0.8mm, other parameters are fixed, and only the thickness is adjusted. A series of parametric finite element analyses are performed to calculate the values ​​of the center layer nodes around the hole, thus obtaining the thickness. Figure 4 The diagram shows the mapping curves between the triaxiality factor and the thickness-to-diameter ratio. When the thickness is 6 mm (B / d=1.0), the triaxiality factor is 0.70; when the thickness is 7.2 mm (B / d=1.2), the triaxiality factor is 0.77; and when the thickness is 9 mm (B / d=1.5), the triaxiality factor is 0.79 and tends to stabilize.

[0073] In this embodiment, to ensure that the triaxiality factor value of the simulated specimen matches the target triaxiality factor and is within the constraint saturation region, a thickness of 7.5 mm is selected. At this time, B / d=1.25, and the corresponding triaxiality factor value is approximately 0.78, which meets the equivalence requirements.

[0074] In this embodiment, the nominal stress of the net cross-section is obtained based on the acquired local peak stress and the actual stress concentration factor, and is calculated using the formula for calculating the nominal stress of the net cross-section. The net cross-sectional area of ​​the simulated specimen is determined based on the plate width, thickness, and diameter of the circular hole of the geometric configuration, and is calculated using the formula for calculating the net cross-sectional area. The loading load required to be applied to the geometric configuration is determined based on the product of the nominal stress of the net cross-section and the net cross-sectional area.

[0075] In this embodiment, the designed specimen drawings (W=24mm, d=6mm, B=7.5mm, r=0.8mm) are processed. After processing, all specimens are placed in a vacuum furnace and subjected to stress-relief annealing at 650℃ for 2 hours, followed by furnace cooling. For the annealed specimens, the surface residual stress in three directions (0°, 45°, and 90°) at the hole edge can be measured by sampling using an X-ray diffractometer, and the average value is recorded (usually it should be at a low level, such as within ±50MPa) to ensure that the initial state of the specimens is consistent and does not affect the dispersion and comparability of the fatigue test results.

[0076] The simulated specimens fabricated using the design parameters in this embodiment were tested on an electro-hydraulic servo fatigue testing machine. Metallographic analysis showed that fatigue cracks all initiated at the maximum stress point at the hole edge, consistent with the finite element prediction and the actual failure location of the turbine disk. The obtained SN curves (stress-life curves) showed significant differences in the long-life region (high-cycle fatigue) compared to traditional notched specimens using the same material and similar target elastic stress concentration factors, but without considering stress gradients and constraint equivalence. Furthermore, they showed a higher degree of agreement with the local fatigue life of the component predicted by the finite element method. This fully demonstrates the effectiveness and superiority of this embodiment in reproducing the actual local fatigue behavior of components.

[0077] Corresponding to the component fatigue weak zone simulation specimen design method in the above embodiment, Figure 5 This is a structural block diagram of a component fatigue weak zone simulation specimen design device provided in one embodiment of this application. For ease of explanation, only the parts relevant to the embodiment of this application are shown. References Figure 5 The component fatigue weak zone simulation specimen design device 20 includes: parameter acquisition module 21, geometric configuration acquisition module 22, target parameter acquisition module 23, load acquisition module 24, and design document generation module 25.

[0078] Among them, the parameter acquisition module 21 is used to acquire the characteristic parameters corresponding to the fatigue weak area of ​​the target turbine component. The characteristic parameters include the target elastic stress concentration factor, stress gradient distribution curve and triaxiality factor. The geometry acquisition module 22 is used to acquire the geometry of the simulated specimen and the diameter of the circular hole in the geometry. The target parameter acquisition module 23 is used to determine the target parameters of the geometric configuration based on the feature parameters, geometric configuration and the diameter of the circular hole. The target parameters include the width, chamfer radius and thickness of the geometric configuration. The load acquisition module 24 is used to acquire the peak stress corresponding to the fatigue weak area of ​​the target turbine component, and determine the loading load required for the geometric configuration based on the peak stress and target parameters. The design document generation module 25 is used to generate design documents for the simulation specimen based on the target parameters and the applied load.

[0079] In one embodiment of this application, the target parameter acquisition module 23, when determining the width of the geometric configuration, is specifically used for: Obtain the theoretical elastic stress concentration factor for the geometric configuration; Based on the theoretical elastic stress concentration factor and the diameter of the circular hole, and using the formula for the theoretical stress concentration factor of the central hole plate, the width of the geometric configuration is determined. The formula for the theoretical stress concentration factor of the central hole plate is as follows: ,in, This represents the theoretical elastic stress concentration factor. The diameter of the circular hole representing the geometric configuration. Indicates the width of the geometric configuration.

[0080] In one embodiment of this application, the target parameter acquisition module 23, when determining the thickness of the geometric configuration, is specifically used for: Based on the triaxiality factor and the diameter of the circular hole, and through parametric finite element analysis, the mapping relationship between the thickness of the geometric configuration and the triaxiality factor is determined. The target thickness-to-diameter ratio is determined based on the mapping relationship and the triaxiality factor; The thickness of the geometric configuration is determined based on the target thickness-to-diameter ratio and the diameter of the circular hole. The thickness-to-diameter ratio is the ratio of the thickness of the geometric configuration to the diameter of the circular hole.

[0081] In one embodiment of this application, the target parameter acquisition module 23, when determining the chamfer radius of the geometric configuration, is specifically used for: Set the initial chamfer radius; Adjust the initial chamfer radius according to the preset step size, calculate the error between the actual stress concentration factor and the target elastic stress concentration factor of the geometric configuration after each adjustment, and the radial stress gradient distribution curve of the geometric configuration. The chamfer radius of the geometric configuration is the adjusted chamfer radius where the error is within the preset error range and the relative error between the radial stress gradient distribution curve and the stress gradient distribution curve is less than or equal to the preset curve error.

[0082] In one embodiment of this application, the target parameter acquisition module 23, after determining the target parameters of the geometric configuration, is specifically used for: Based on the width, diameter of the circular hole, and thickness of the geometric configuration, the net cross-sectional area of ​​the geometric configuration is calculated using the net cross-sectional area calculation formula. The net cross-sectional area calculation formula is as follows: ,in, Represents the net cross-sectional area of ​​the geometric configuration. Indicates the diameter of the circular hole. The width of the plate representing the geometric configuration. Indicates the thickness of the geometric configuration.

[0083] In one embodiment of this application, the load acquisition module 24, when determining the loading load required for the geometric configuration, is specifically used for: Obtain the actual stress concentration factor corresponding to the chamfer radius; Determine the stress corresponding to the net cross-sectional area based on the peak stress and the actual stress concentration factor; The product of stress and net cross-sectional area of ​​the geometry is used as the load required for the geometry.

[0084] In one embodiment of this application, the target parameter acquisition module 23, after determining the loading load required for the geometric configuration, is further configured to: Stress annealing is applied to the geometry; and / or Fatigue tests are conducted on the geometry based on the applied load to obtain the fatigue test results of the geometry, and the residual stress field on the edge surface of the circular hole of the geometry is obtained. The fatigue test results are then corrected based on the residual stress field to obtain the corrected fatigue test results.

[0085] It should be noted that the specific limitations of the above-described component fatigue weak zone simulation specimen design device 20 can be found in the limitations of the component fatigue weak zone simulation specimen design method described above, and will not be repeated here. Each module of the above device can be implemented entirely or partially through software, hardware, or a combination thereof. Each module can be embedded in the processor of the electronic device in hardware form or independent of the processor, or it can be stored in the memory of the electronic device in software form, so that the processor can call and execute the corresponding operations of each module.

[0086] This application provides an electronic device, including a memory, a processor, and a computer program stored in the memory. The processor executes the computer program to implement the steps of the method provided in any optional embodiment of this application.

[0087] In one alternative embodiment, an electronic device is provided, such as Figure 6 As shown, Figure 6 The illustrated electronic device 300 includes a processor 301 and a memory 303. The processor 301 and the memory 303 are connected, for example, via a bus 302. Optionally, the electronic device 300 may further include a transceiver 304, which can be used for data interaction between the electronic device and other electronic devices, such as sending and / or receiving data. It should be noted that in practical applications, the transceiver 304 is not limited to one type, and the structure of this electronic device 300 does not constitute a limitation on the embodiments of this application.

[0088] Processor 301 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. Processor 301 may also be a combination that implements computational functions, such as including one or more microprocessor combinations, a combination of a DSP and a microprocessor, etc.

[0089] Bus 302 may include a pathway for transmitting information between the aforementioned components. Bus 302 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. Bus 302 can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 6 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0090] The memory 303 may be ROM (Read Only Memory) or other types of static storage devices capable of storing static information and instructions, RAM (Random Access Memory) or other types of dynamic storage devices capable of storing information and instructions, or EEPROM (Electrically Erasable Programmable Read Only Memory), CD-ROM (Compact Disc Read Only Memory) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media, other magnetic storage devices, or any other medium capable of carrying or storing computer programs and capable of being read by a computer, without limitation herein.

[0091] The memory 303 is used to store computer programs that execute the embodiments of this application, and the execution is controlled by the processor 301. The processor 301 is used to execute the computer programs stored in the memory 303 to implement the steps shown in the foregoing method embodiments.

[0092] In an exemplary embodiment, a computer-readable storage medium is also provided, which stores at least one computer program, which is loaded and executed by a processor of a computer device to enable the computer to implement any of the above-described methods for designing simulated specimens of fatigue weak zones in components.

[0093] In one possible implementation, the aforementioned computer-readable storage medium can be a read-only memory (ROM), a random access memory (RAM), a solid-state drive (SSD), a compact disc read-only memory (CD-ROM), magnetic tape, a floppy disk, and an optical data storage device, etc. The random access memory can include resistive random access memory (ReRAM) and dynamic random access memory (DRAM).

[0094] It should be further noted that the terms "first," "second," etc., used in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. The implementation methods described in the above exemplary embodiments do not represent all implementation methods consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application.

[0095] It should be understood that "multiple" as used in this article refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0096] Furthermore, the step numbers described herein are merely illustrative of one possible execution order between steps. In some other embodiments, the steps may not be executed in the order of their numbers, such as two steps with different numbers being executed simultaneously, or two steps with different numbers being executed in the reverse order of the illustration. This application does not limit this.

[0097] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. Optionally, the program is stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0098] The above description is merely an exemplary embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this application should be included within the protection scope of this application.

Claims

1. A method for designing simulated fatigue weak zones of components, characterized in that, include: Obtain the characteristic parameters corresponding to the fatigue weak areas of the target turbine component, including the target elastic stress concentration factor, stress gradient distribution curve, and triaxiality factor; Obtain the geometric configuration of the simulated specimen, and obtain the diameter of the circular hole in the geometric configuration; Based on the characteristic parameters, the geometric configuration, and the diameter of the circular hole, the target parameters of the geometric configuration are determined, including the width, chamfer radius, and thickness of the geometric configuration. Obtain the peak stress corresponding to the fatigue weak area of ​​the target turbine component, and determine the loading load required for the geometric configuration based on the peak stress and the target parameters; Based on the target parameters and the applied load, a design file for the simulated specimen is generated.

2. The method as described in claim 1, characterized in that, The method for determining the width of the geometric configuration includes: Obtain the theoretical elastic stress concentration factor for the given geometric configuration; Based on the theoretical elastic stress concentration factor and the diameter of the circular hole, and using the formula for the theoretical stress concentration factor of the central hole plate, the width of the geometric configuration is determined. The formula for the theoretical stress concentration factor of the central hole plate is as follows: ,in, This represents the theoretical elastic stress concentration factor. The diameter of the circular hole representing the geometric configuration. Indicates the width of the geometric configuration.

3. The method as described in claim 1, characterized in that, The method for determining the thickness of the geometric configuration includes: Based on the triaxiality factor and the diameter of the circular hole, and through parametric finite element analysis, the mapping relationship between the thickness of the geometric configuration and the triaxiality factor is determined; The target thickness-to-diameter ratio is determined based on the mapping relationship and the triaxiality factor. The thickness of the geometric configuration is determined based on the target thickness-to-diameter ratio and the diameter of the circular hole, wherein the thickness-to-diameter ratio is the ratio of the thickness of the geometric configuration to the diameter of the circular hole.

4. The method as described in claim 2, characterized in that, The method for determining the chamfer radius of the geometric configuration includes: Set the initial chamfer radius; The initial chamfer radius is adjusted according to a preset step size, and the error between the actual stress concentration factor and the target elastic stress concentration factor of the geometric configuration after each adjustment is calculated, as well as the radial stress gradient distribution curve of the geometric configuration. The chamfer radius of the geometric configuration is the adjusted chamfer radius where the error is within a preset error range and the relative error between the radial stress gradient distribution curve and the stress gradient distribution curve is less than or equal to the preset curve error.

5. The method as described in claim 4, characterized in that, After determining the target parameters of the geometric configuration, the method further includes: Based on the width of the geometric configuration, the diameter of the circular hole, and the thickness of the geometric configuration, the net cross-sectional area of ​​the geometric configuration is calculated using the net cross-sectional area calculation formula; wherein, the net cross-sectional area calculation formula is as follows: ,in, Represents the net cross-sectional area of ​​the geometric configuration. Indicates the diameter of the circular hole. The width of the plate representing the geometric configuration. Indicates the thickness of the geometric configuration.

6. The method as described in claim 5, characterized in that, The loading load required to determine the geometry includes: Obtain the actual stress concentration factor corresponding to the chamfer radius; The stress corresponding to the net cross-sectional area is determined based on the peak stress and the actual stress concentration factor. The product of the stress and the net cross-sectional area of ​​the geometry is taken as the required loading load for the geometry.

7. The method as described in claim 1, characterized in that, After determining the required loading load for the geometry, the method further includes: The geometry is subjected to stress annealing; and / or A fatigue test is performed on the geometric configuration according to the applied load to obtain the fatigue test results of the geometric configuration, and the residual stress field of the circular hole edge surface of the geometric configuration is obtained. The fatigue test results are then corrected based on the residual stress field to obtain the corrected fatigue test results.

8. A device for designing simulated fatigue weak zones of components, characterized in that, include: The parameter acquisition module is used to acquire the characteristic parameters corresponding to the fatigue weak areas of the target turbine component. The characteristic parameters include the target elastic stress concentration factor, stress gradient distribution curve, and triaxiality factor. A geometry configuration acquisition module is used to acquire the geometry configuration of the simulated specimen and the diameter of the circular hole in the geometry configuration; The target parameter acquisition module is used to determine the target parameters of the geometric configuration based on the feature parameters, the geometric configuration, and the diameter of the circular hole. The target parameters include the width, chamfer radius, and thickness of the geometric configuration. The load acquisition module is used to acquire the peak stress corresponding to the fatigue weak area of ​​the target turbine component, and determine the loading load required for the geometric configuration based on the peak stress and the target parameters. The design document generation module is used to generate the design document of the simulation specimen based on the target parameters and the applied load.

9. An electronic device, characterized in that, The electronic device includes a processor and a memory, the memory storing a computer program, which is loaded and executed by the processor to implement the component fatigue weak zone simulation specimen design method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which is loaded and executed by a processor to implement the component fatigue weak zone simulation specimen design method as described in any one of claims 1 to 7.

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