Axial limit ring deformation optimization design method and system

Abstract

The application discloses an axial limiting ring deformation optimization design method and system. By establishing a system three-dimensional finite element model, the stress-strain variation law of the axial limiting ring is simulated by adopting a Chaboche follow-up reinforcement material constitutive model, a heat-force coupling load spectrum is applied for deformation analysis, and a systematic heat-force coupling failure evaluation method is established, so that the axial limiting ring can be prevented from being caused to be out of the system due to deformation in a working state, and safe and reliable working of the axial limiting ring is ensured. The width and the thickness of an opening of the axial limiting ring are taken as initial design variables, the heat-force coupling failure evaluation method is taken as a target constraint function, a response surface model is adopted to establish a multi-target optimization function, and a genetic algorithm is used to seek an optimal solution of the axial limiting ring. The application improves the design efficiency of the axial limiting ring in resisting deformation, and has important theoretical and practical values for guaranteeing system safety.

Description

Technical Field

[0001] This invention belongs to the field of strength design technology for hot-end components of aero-engines, and specifically relates to a deformation optimization design method and system for an axial limiting ring, which is particularly suitable for fatigue failure prevention design and structural optimization of axial limiting rings in turbine components under thermo-mechanical coupled load conditions. Background Technology

[0002] Axial limiting rings are generally open annular structures that can undergo appropriate elastic deformation in the radial direction. They are installed in the concave groove of the turbine casing through the elastic deformation of the metal to prevent other parts installed in the groove or on the shaft from axial movement, thus playing an axial limiting role.

[0003] Currently, in the design of turbine guide vanes for aero-engines, axial limiting rings are mainly used to limit axial movement and block cooling airflow. These axial limiting rings are primarily open annular structures, fitted into the U-shaped groove of the turbine casing to provide axial control for the turbine guide vane. However, due to the cyclic temperature loads on the turbine components, the limiting rings undergo plastic deformation during long-term use. This plastic deformation accumulates under cyclic loads, eventually causing the axial limiting ring to detach from its mounting groove in the turbine casing, leading to its failure and secondary damage to other components, thus affecting engine operating safety.

[0004] Currently, the failure of engine axial retaining rings is relatively rare, and research on corresponding failure modes and strength design methods is also limited. Existing technologies typically employ general strength assessment methods for engine casings to evaluate the strength of axial retaining rings. However, this method struggles to accurately assess the stress-strain and deformation characteristics of the retaining ring under complex thermo-mechanical coupling environments, posing a significant assessment risk. Furthermore, existing design methods lack optimization techniques for the opening structural parameters of the axial retaining ring, making it difficult to achieve efficient structural design while meeting safety margins.

[0005] Therefore, it is urgent to establish a thermo-mechanical coupling evaluation method for axial restraint ring failure, and to establish a structural optimization design process based on this evaluation method, so as to apply it to the strength design of aero-engines, improve the strength design system, and ensure the safety of engine service. Summary of the Invention

[0006] The purpose of this invention is to address the technical problems of existing axial restraint ring strength assessment methods, which are unable to accurately assess the stress-strain and deformation characteristics of restraint rings under thermo-mechanical coupling environments and lack structural parameter optimization methods. The invention aims to provide an axial restraint ring deformation optimization design method and system that can effectively assess the deformation failure risk of axial restraint rings under thermo-mechanical coupling loads and achieve rapid optimization of structural parameters.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for optimizing the deformation of an axial limiting ring, wherein the axial limiting ring has a beveled opening, the method comprising the following steps: S1. Establish a three-dimensional finite element model of the system, which includes a turbine casing, an axial limiting ring, a turbine guide, and a honeycomb ring; the stress-strain variation law of the axial limiting ring is simulated using the Chaboche constitutive model of kinematic strengthening material. S2. Determine the thermo-mechanical load spectrum for the deformation analysis of the axial limiting ring. The load spectrum includes the temperature field and axial force. Establish a thermo-mechanical coupled cyclic load spectrum loading method that considers the cyclic loading sequence. S3. Establish a system thermo-mechanical coupling failure assessment method, apply the load spectrum to the finite element model, obtain the deformation assessment parameters of the axial limiting ring, and determine whether the axial limiting ring meets the safety requirements according to the failure judgment criteria. S4. Establish a multi-objective optimization process for the system. Take the opening length and cross-sectional width of the axial limiting ring as design variables, the thermo-mechanical coupling failure assessment method as the objective constraint function, establish a multi-objective optimization function using a response surface model, and solve the multi-objective optimization function using a genetic algorithm to find the opening length and cross-sectional width of the axial limiting ring that minimize the multi-objective optimization function, which is taken as the optimal solution for the axial limiting ring.

[0008] Preferably, in step S1, the axial limiting ring has a beveled opening design, that is, the angle between the opening direction and the circumferential outer ring is an acute angle.

[0009] Preferably, in step S1, the constitutive model of the Chaboche kinematic strengthening material is:

[0010]

[0011] in, For the material's yield strength, For equivalent plastic strain, To enhance the modulus, To enhance the modulus attenuation rate, n is set to 3; the model parameters are obtained by fitting the stress-plastic strain curve of the uniaxial monotonic tensile test of the standard specimen of the axial restraint ring material.

[0012] Preferably, in step S2, the loading method of the thermo-mechanical coupled cyclic load spectrum includes loading the first operating condition cyclic load spectrum and loading the second operating condition load. Loading the first operating condition cyclic load spectrum includes the following steps performed sequentially: The first step is to apply the axial force generated by the internal flow under the peak temperature state of the transient temperature field under the first working condition load, where the first working condition is the engine emergency takeoff working condition; The second step is to apply the axial force generated by the internal flow and the nonlinear transient thermal simulation temperature field under the peak temperature state of the transient temperature field under the first working condition load. The third step is to apply the nonlinear transient thermal simulation temperature field generated by the internal flow under the peak temperature state of the transient temperature field under the first working condition load, without applying axial force; The fourth step is to apply room temperature only.

[0013] The first to fourth steps above constitute the complete loading process for the first working condition cyclic load spectrum, which is used to evaluate the plastic strain accumulation of the axial retaining ring under cyclic load.

[0014] The second operating condition load is used to evaluate the radial fit clearance between the axial limiting ring and the honeycomb ring. The second operating condition is the engine emergency shutdown condition.

[0015] Preferably, in step S3, the deformation evaluation parameters include: the equivalent plastic strain rate of the axially restraining ring. The percentage of unit volume undergoing plastic deformation (R), and the radial gap between the axial limiting ring and the honeycomb ring after cyclic load deformation. And the radial clearance between the axial limiting ring and the honeycomb ring under the second working condition. ; The failure determination criteria are as follows: Less than the preset strain rate safety threshold, R is less than the preset volume percentage safety threshold, Greater than zero Greater than zero.

[0016] Preferably, in step S4, the response surface model is:

[0017] Where m=2, Let L be the opening length of the axial limiting ring. Let t be the cross-sectional width of the axial limiting ring. , , These are the fitting parameters for the response surface model.

[0018] Preferably, in step S4, the multi-objective optimization function is:

[0019] in, , , , These are the weighting coefficients, and .

[0020] The present invention also provides an axial limiting ring deformation optimization design system for implementing the above method, the system comprising: The 3D finite element model building module is used to build a 3D finite element model of the system, including the turbine casing, axial limiting ring, turbine guide, and honeycomb ring. The material constitutive determination module is used to simulate the stress-strain variation of the axially confined ring using the Chaboche kinematic strengthening material constitutive model. The load spectrum determination module is used to determine the thermo-mechanical load spectrum for deformation analysis of the axial retaining ring and establish a loading method for thermo-mechanical coupled cyclic load spectrum. The loading method includes a first-condition cyclic load spectrum loading and a second-condition load loading. The first-condition cyclic load spectrum loading sequentially includes: applying the axial force generated by the internal flow under the peak temperature state of the transient temperature field under the first-condition load; applying the axial force generated by the internal flow under the peak temperature state of the transient temperature field under the first-condition load and a nonlinear transient thermal simulation temperature field; applying the nonlinear transient thermal simulation temperature field generated by the internal flow under the peak temperature state of the transient temperature field under the first-condition load, without applying the axial force; and applying only room temperature. The second-condition load loading is used to evaluate the radial fit clearance between the axial retaining ring and the honeycomb ring. The thermo-mechanical coupling failure assessment module is used to apply the load spectrum to the finite element model, obtain the deformation assessment parameters of the axial limiting ring, and determine whether the axial limiting ring meets the safety requirements according to the failure judgment criteria. The multi-objective optimization module is used to establish a multi-objective optimization function with the opening length and cross-sectional width of the axial restraint ring as design variables, the thermo-mechanical coupling failure assessment method as the objective constraint function, and a response surface model. The module then uses a genetic algorithm to solve the multi-objective optimization function and seeks the opening length and cross-sectional width of the axial restraint ring that minimize the multi-objective optimization function, which are then taken as the optimal solution for the axial restraint ring.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention establishes a systematic thermo-mechanical coupling failure assessment method. By establishing a three-dimensional finite element model of the system and applying a thermo-mechanical coupling load spectrum, it can accurately assess the stress, strain, and deformation characteristics of the axial retaining ring under complex thermo-mechanical environments. This can effectively prevent the deformation of the axial retaining ring in the working state from causing it to dislodge, ensuring its safe and reliable operation. This overcomes the shortcomings of the existing technology, which uses a general strength assessment method for casings, which cannot accurately assess the failure risk of the retaining ring.

[0022] 2. This invention simulates the cyclic plastic deformation behavior of an axially restrained ring based on the Chaboche kinematic reinforcement constitutive model, which can more accurately describe the stress-strain response of the restrained ring under cyclic thermo-mechanical loads, providing an accurate material constitutive basis for failure assessment.

[0023] 3. This invention establishes a thermo-mechanical coupled cyclic load spectrum loading method that considers the cyclic loading sequence, which can realistically simulate the load history of the axial limiting ring in actual work and improve the accuracy of deformation analysis.

[0024] 4. This invention establishes a multi-objective optimization process based on response surface methodology and genetic algorithm. With the opening length and cross-sectional width of the axial limiting ring as design variables and the thermo-mechanical coupling failure assessment method as the objective constraint function, it can quickly find the optimal solution for the axial limiting ring, shorten the design cycle, and improve the design efficiency of the axial limiting ring. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the system device structure provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the axial limiting ring structure provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the output variable position of the axial limiting ring provided in an embodiment of the present invention; Figure 4 This is a flowchart of the axial limiting ring evaluation process provided in an embodiment of the present invention. Detailed Implementation

[0026] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0027] Example 1 This embodiment provides an axial limiting ring deformation optimization design system, which includes two parts: physical structure and functional modules.

[0028] (I) Physical Structure like Figure 1 As shown, the system includes an axial limiting ring 1, a honeycomb ring 2, a turbine casing 3, and a turbine guide 4.

[0029] The turbine guide 4 is attached to the mounting base of the turbine casing 3. The axial limiting ring 1 is fitted in the U-shaped groove of the turbine casing 3, which serves to limit the axial movement of the turbine guide 4 and block the cooling gas. The honeycomb ring 2 is fitted on the turbine casing 3 and is connected to the turbine casing 3 circumferentially by multiple radial pins. Its front end is designed with lace claws to prevent the ring from radially dislodging from the groove.

[0030] like Figure 2As shown, the axial limiting ring 1 has a beveled opening design, meaning the angle between the opening direction and the circumferential outer ring is acute, and the distance between the two opening end faces is L. During operation, because the temperature of the turbine casing is lower than that of the axial limiting ring, the axial limiting ring is under pressure. The beveled opening design causes one end of the axial limiting ring to press against the other end, and the pressured end will deform inward in the radial direction. This deformation can release the stress in the axial limiting ring 1.

[0031] (II) Functional Modules Based on the above physical structure, the system further includes the following functional modules for implementing the deformation optimization design method described in this invention: 1. Three-dimensional finite element model creation module The 3D finite element model creation module is used to create a 3D finite element model of the system, including the turbine casing, axial restraint ring, turbine guide vane, and honeycomb ring. Taking the geometric models and material properties of each component as input, this module performs the following operations in the finite element analysis preprocessing platform: establishing contact elements on the radial contact surface between the axial restraint ring and the turbine casing to transmit radial force; establishing contact elements on the axial contact surface between the axial restraint ring and the turbine casing and turbine guide vane to transmit axial force; establishing contact elements on all contact surfaces between the honeycomb ring and the turbine casing; and establishing axial displacement consistency equations at the pin locations to simulate pin connections. The module outputs a complete finite element model file containing contact relationships and constraint conditions.

[0032] 2. Material Constitutive Determination Module The material constitutive determination module is used to simulate the stress-strain variation of an axially restrained ring using the Chaboche kinematic hardening material constitutive model. This module takes the stress-plastic strain data from uniaxial monotonic tensile tests of standard specimens of the axially restrained ring material as input and calculates the parameters in the Chaboche kinematic hardening model through curve fitting. and (i=1,2,3), the specific mathematical form of the model is shown in equations (1)~(2). The output of this module is the constitutive parameter set of the axial restraint ring material, which is called by the finite element solver. The material properties of the turbine casing, turbine guide, and honeycomb ring are directly set as linear elastic materials in the three-dimensional finite element model building module.

[0033] 3. Load spectrum determination module The load spectrum determination module is used to determine the thermo-mechanical load spectrum for the deformation analysis of the axial limiting ring and to establish a loading method for the thermo-mechanical coupled cyclic load spectrum. This module takes engine operating parameters as input, performs nonlinear transient thermal simulation analysis using fluid dynamics software to obtain the system temperature field, and calculates the system axial force by combining the aerodynamic forces of the guide vane, the thermal expansion of each component, and frictional forces.

[0034] The loading method established in this module includes two independent branches: a first-condition cyclic load spectrum loading and a second-condition load loading. The first-condition cyclic load spectrum loading is executed sequentially: loading the axial force generated by the internal flow at the peak temperature of the transient temperature field under the first-condition load; loading the axial force generated by the internal flow at the peak temperature of the transient temperature field under the first-condition load and the nonlinear transient thermal simulation temperature field; loading the nonlinear transient thermal simulation temperature field generated by the internal flow at the peak temperature of the transient temperature field under the first-condition load, without loading the axial force; and loading only at room temperature. The second-condition load loading is used to evaluate the radial fit clearance between the axial restraint ring and the honeycomb ring, and is a single load loading. The output of this module is a temperature field load file and an axial force load file that can be used by the finite element solver.

[0035] 4. Thermo-mechanical coupling failure assessment module The thermo-mechanical coupling failure assessment module is used to apply the load spectrum to the finite element model to obtain the deformation assessment parameters of the axial restraint ring, and to determine whether the axial restraint ring meets the safety requirements according to the failure judgment criteria. This module takes the finite element model output by the three-dimensional finite element model establishment module, the material constitutive parameters output by the material constitutive determination module, and the load spectrum file output by the load spectrum determination module as input, and calls the finite element solver to perform the calculation.

[0036] This module extracts the following deformation evaluation parameters through a finite element post-processing secondary development program: the equivalent plastic strain rate of the axial restraint ring. (Calculation method is shown in Equation (3)); the proportion of unit volume that undergoes plastic deformation R (calculation method is shown in Equation (4)); the radial gap between the axial limiting ring and the honeycomb ring after deformation under the first working condition cyclic load. (Calculation method is shown in equations (5) to (7)); Radial clearance between the axial limiting ring and the honeycomb ring under the second working condition (The calculation method is shown in equation (8)).

[0037] This module has built-in failure detection logic: when Less than the preset strain rate safety threshold (10 in this embodiment) -4 R is less than the preset volume percentage safety threshold (0.06 in this embodiment). Greater than zero If the value is greater than zero, the current design is deemed to meet the safety requirements; otherwise, it is deemed not to meet the requirements, and suggestions for adjusting the design variables are output.

[0038] 5. Multi-objective optimization module The multi-objective optimization module is used to establish a multi-objective optimization function with the opening length and cross-sectional width of the axial restraint ring as design variables, the thermo-mechanical coupling failure assessment method as the objective constraint function, and a response surface model, and to seek the optimal solution of the axial restraint ring using a genetic algorithm.

[0039] This module first performs parametric modeling of the axial limiting ring, using the opening length L and cross-sectional width t of the axial limiting ring as initial design variables, and determines the design space by the range constraints of the design variables. This module uses the Latin hypercube sampling method to randomly generate z experimental design sample points in the design space, and uses an engineering simulation software platform to calculate the response sets of the four output variables corresponding to each sample point. The design matrix is ​​constructed based on the response surface method (see Equation (9)), and the response surface model is fitted using the least squares method. This module constructs a weighted optimization objective function (see Equation (10)) and has a built-in genetic algorithm solver. Using the objective optimization function as the fitness function and the design variables as optimization variables, it performs global optimization within the constraint range of each design variable, and outputs the opening length L and cross-sectional width t corresponding to the minimum value of the objective optimization function, as the optimal design solution of the axial limiting ring.

[0040] The above modules can be integrated into the same engineering simulation software platform, or they can call each other through data interfaces to form a complete optimization design process.

[0041] Example 2 This embodiment provides a method for optimizing the deformation design of an axial limiting ring, including the following steps.

[0042] S1. Establish a three-dimensional finite element model of the system.

[0043] A three-dimensional finite element model of the system, consisting of a turbine casing, an axial retaining ring, a turbine guide vane, and a honeycomb ring, was established. Radial force was transmitted between the axial retaining ring and the turbine casing via contact elements on their radial contact surfaces; axial force was transmitted between the axial retaining ring and the turbine casing and turbine guide vane via contact elements on their axial contact surfaces; contact elements were established on all contact surfaces between the honeycomb ring and the turbine casing; and an axial displacement coordination equation was established at the pin locations for simulation.

[0044] The turbine casing, turbine guide vane, and honeycomb ring are calculated using linear elastic materials. The axial retaining ring is calculated using Chaboche kinematically reinforced constitutive materials. The constitutive model of Chaboche kinematically reinforced materials is shown in formulas (1) to (2): ……………………………(1) …………………………(2) in: For the material's yield strength, For equivalent plastic strain, Strengthening modulus, To enhance the modulus decay rate, n is set to 3.

[0045] The parameters in the model are determined as follows: based on the stress-strain data of the uniaxial monotonic tensile test of the standard specimen of the axial restraint ring material, the stress-plastic strain curve of the material is obtained, and the strengthening modulus parameter is calculated by fitting the plastic stage curve. and The value of .

[0046] S2. Determine the thermo-mechanical load spectrum for the deformation analysis of the axial limiting ring.

[0047] The load spectrum to be analyzed mainly includes the temperature field and axial force. The temperature field of the system consisting of the turbine casing, axial limiting ring, turbine guide vane, and honeycomb ring needs to be obtained through nonlinear transient thermal simulation analysis using fluid dynamics (CFD) software, with engine operating conditions (such as throttle position, intake air temperature, and cooling airflow distribution) as input, based on the system's transient thermal boundary conditions. The axial force of the system consists of the aerodynamic force of the turbine guide vane, the thermal expansion of each component, and frictional forces.

[0048] First, we need to analyze the plastic strain of the axial limiting ring under the first operating condition (emergency takeoff) cyclic load of the engine. Under the first operating condition load, the outer surface temperature of the turbine casing in the system is low, while the temperature of the turbine guide vane in the flow channel is high. Under the action of aerodynamic force, the turbine guide vane makes axial contact with the axial limiting ring, and the temperature of the axial limiting ring is also high. At this time, there is a temperature difference between the axial limiting ring and the turbine casing.

[0049] Considering the loading and unloading sequence of cyclic loads, a loading method for the thermo-mechanical coupled cyclic load spectrum of the system is established to obtain the plastic strain of the axial restraining ring under cyclic load. The loading steps for the first working condition cyclic load spectrum are as follows: The first step is to apply the axial force generated by the internal flow under the peak temperature state of the transient temperature field under the first working condition load. The second step is to apply the axial force generated by the internal flow and the nonlinear transient thermal simulation temperature field under the peak temperature state of the transient temperature field under the first working condition load. The third step is to apply the nonlinear transient thermal simulation temperature field generated by the internal flow under the peak temperature state of the transient temperature field under the first working condition load, without applying axial force; The fourth step is to apply room temperature only.

[0050] The first to fourth steps above constitute the complete loading process for the first working condition cyclic load spectrum, which is used to evaluate the plastic strain accumulation of the axial retaining ring under cyclic load.

[0051] Secondly, the radial clearance between the axial limiting ring and the honeycomb ring needs to be analyzed under the second operating condition (emergency shutdown) load of the engine. Under the second operating condition load, the turbine casing temperature in the system is high, while the temperature of the axial limiting ring is low due to cold air convection heat transfer, resulting in a decrease in the radial clearance between the axial limiting ring and the honeycomb ring. Therefore, it is necessary to evaluate the radial fit status between the axial limiting ring and the honeycomb ring. This step is independent of the first operating condition cyclic load spectrum loading process described above; it is a single load loading process used to evaluate the radial clearance between the axial limiting ring and the honeycomb ring under the second operating condition.

[0052] S3. Establish a system thermo-mechanical coupling evaluation method.

[0053] Based on the finite element model of the system established in step S1, N cyclic load spectra from step S2 are applied to obtain the calculation results under N cyclic load spectra. Using a finite element post-processing secondary development program, the equivalent plastic strain of the axial restraint ring under N cyclic load spectra is output, and the equivalent plastic strain rate of the axial restraint ring is calculated, as shown in formula (3): ……………………………(3) In the formula: , Let N be the plastic strain of the axial retaining ring after the Nth and N+1th cyclic loading, where N is the cycle number of the first working condition set in the system operation. =1.

[0054] The finite element post-processing secondary development program outputs the element volume of the axial limiting ring entering plastic deformation and calculates the proportion R of the element volume where plastic deformation occurs. ………………………………(4) In equation (4): Let be the unit volume of the axial retaining ring after the Nth cyclic loading when plastic deformation occurs. This represents the total volume of the axial limiting ring.

[0055] The radial deformation of the axial limiting ring and the honeycomb ring after N cyclic loads is output through the finite element post-processing secondary development program. The radial clearance in the diameter direction between the axial limiting ring and the honeycomb ring after the deformation of the Nth cyclic load is calculated as shown in formula (5): ……………………………(5) In the formula: Position of axial limiting ring The diameter after deformation under the Nth cyclic load; The initial diameter of the honeycomb ring clamp is [missing information]. and Position such as Figure 3 As shown.

[0056] The coordinate values ​​of points A, B, and C of the axial limiting ring after deformation under the Nth cyclic load were obtained through a finite element post-processing secondary development program. The positions of points A, B, and C are as follows: Figure 2 As shown, A is the point where the chamfer angle of the inner diameter of the axial limiting ring is acute; B is the node with the largest radial residual deformation of the inner diameter under the Nth cyclic load of the axial limiting ring; and C is the node located no more than three nodes away from point B along the circumferential direction. The coordinate values ​​(x, y, c) of points A, B, and C are then... a ,y a ), (x b ,y b ), (x c ,y c Substitute these values ​​into formula (6) to calculate the values ​​of a, b, and c, and then calculate the diameter according to formula (7). Where x a x b x c The radial coordinate value is y. a y b y c These are the circumferential coordinate values.

[0057] …………………………(6) …………………………(7) Based on the system finite element model established in step S1, apply the load under the second working condition and calculate the radial clearance between the axial limiting ring and the honeycomb ring: …………………………(8) In the formula: Location of the honeycomb ring Radial displacement under the second operating condition; Position of axial limiting ring Radial displacement under the second operating condition; This represents the initial radial gap between the axial limiting ring and the honeycomb ring.

[0058] Establish failure criteria: Determine the equivalent plastic strain rate of the axial retaining ring. Is it less than the preset strain rate safety threshold (10)? -4 ); Determine whether the unit volume ratio R of the plastic deformation of the axial limiting ring is less than the preset volume ratio safety threshold (0.06); Determine the radial gap between the axial limiting ring and the honeycomb ring in the diameter direction under the Nth cyclic load spectrum. Is it greater than zero? Determine the radial clearance between the axial limiting ring and the honeycomb ring under the second working condition. Is it greater than zero?

[0059] If any of the above conditions are not met, the design parameters of the axial limiting ring need to be adjusted (such as increasing the opening length L or the cross-sectional width t), and a re-evaluation is required.

[0060] S4. Establish a multi-objective optimization process for the system.

[0061] The evaluation process for axial limiting rings is as follows: Figure 4 As shown, the optimization process includes the following steps: S41. Perform parametric modeling of the axial limiting ring, using the opening length L and cross-sectional width t of the axial limiting ring as initial design variables, where... , Provided by aerodynamic performance constraints, The initial value of t is given by the structure, and the range of t is given by the structure.

[0062] S42. Using Latin hypercube sampling, randomly generate z experimental design sample points.

[0063] S43. Calculate the plastic strain rate corresponding to z sample points using an engineering simulation software platform. The proportion of unit volume in plastic deformation R, and the radial clearance after cyclic load deformation. Radial clearance during emergency stop The response set consists of four output variables. Specifically, by analyzing the calculation results of the axial restraint ring under emergency takeoff-shutdown cyclic loads, the plastic strain rate under N cyclic loads is obtained. Obtain the volume percentage R of the plastic deformation element under N cyclic loads, and obtain the radial gap between the axial limiting ring and the honeycomb ring under N cyclic loads. Furthermore, by analyzing the calculation results of the axial limiting ring under emergency stop load, the radial clearance of the limiting ring in the emergency stop state is obtained. .

[0064] S44. Construct the design matrix using the response surface methodology, as shown in formula (9). Fit the response surface model using the least squares method, and solve for the fitting parameters in formula (9) based on the sample points of the input and output variables: ……………………(9) In the formula: , , Here are the fitting parameters for the response surface model, m=2. Let L be the opening length. Let t be the width of the cross-section.

[0065] S45. Consider single-objective optimization with four output variables (i.e. <10 -4 R < 6%, >0, >0), construct a weighted multi-objective optimization function, as shown in formula (10): …………………(10) In the formula, , , , These are the weighting coefficients, and .

[0066] A genetic algorithm is used for optimization to find the minimum value of the objective function. When the objective function reaches its minimum value, the corresponding design variables (opening length L and cross-sectional width t) are the optimal solution for the axial restraint ring.

[0067] Example 3 This embodiment takes the axial limiting ring of a turbine component of a certain type of aero-engine as an example, and uses the method provided by the present invention for deformation optimization design.

[0068] First, a three-dimensional finite element model of the system was established according to step S1. The axial restraint ring was made of a nickel-based superalloy. The stress-plastic strain curve of the material was obtained through uniaxial monotonic tensile tests, and the Chaboche kinematic hardening model parameters were obtained by fitting: C1=150000MPa, γ1=800, C2=80000MPa, γ2=1500, C3=30000MPa, γ3=3000.

[0069] Secondly, the thermo-mechanical load spectrum is determined according to step S2. Taking the engine's first operating condition (emergency takeoff) and second operating condition (emergency shutdown) as the analysis conditions, the system temperature field is obtained through nonlinear transient thermal simulation analysis using CFD software, and the axial force load is obtained by combining it with aerodynamic calculations.

[0070] Then, a thermo-mechanical coupling failure assessment was performed according to step S3. After applying 10 cyclic load spectra, the equivalent plastic strain rate was calculated. =3.2×10 -5 <10 -4 The volume ratio of plastic deformation units R = 0.032 < 0.06, radial clearance =0.15mm>0, =0.08mm>0, which fully meets the failure judgment criteria, indicating that the current design meets the safety requirements.

[0071] Finally, multi-objective optimization was performed according to step S4. Using the opening length L (initial value 3mm, range 1~6mm) and cross-sectional width t (initial value 3mm, range 2~5mm) as design variables, 50 sample points were generated using Latin hypercube sampling to construct a response surface model, which was then optimized using a genetic algorithm. The optimal solution was obtained after optimization: L=2mm, t=3.5mm. The objective function value was reduced by 42% compared to the initial design, effectively improving the deformation resistance of the axial restraint ring.

[0072] The axial limiting ring deformation optimization design method and system provided in this invention can be widely applied to the strength design and structural optimization of axial limiting rings in aero-engine turbine components. It can also be extended to the design and analysis of other open ring limiting structures with similar thermo-mechanical coupling working environments, and has broad industrial application prospects.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations of the embodiments of the present invention are possible. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for optimizing the deformation design of an axial limiting ring, characterized in that, The axial limiting ring has a beveled opening design, and the method includes the following steps: A three-dimensional finite element model of the system is established. The system includes a turbine casing, an axial restraint ring, a turbine guide, and a honeycomb ring. The stress-strain variation law of the axial restraint ring is simulated using the Chaboche constitutive model of kinematic hardening material. The thermo-mechanical load spectrum for axial restraint ring deformation analysis is determined, the load spectrum including temperature field and axial force, and a thermo-mechanical coupled cyclic load spectrum loading method is established, the loading method including: The first cyclic load spectrum loading includes the following steps performed sequentially: The first step is to apply the axial force generated by the internal flow under the peak temperature state of the transient temperature field under the first working condition load, where the first working condition is the engine emergency takeoff working condition; The second step is to apply the axial force generated by the internal flow and the nonlinear transient thermal simulation temperature field under the peak temperature state of the transient temperature field under the first working condition load. The third step is to apply the nonlinear transient thermal simulation temperature field generated by the internal flow under the peak temperature state of the transient temperature field under the first working condition load, without applying axial force; Fourth step: Apply only room temperature; In addition, a second working condition load is applied to evaluate the radial fit clearance between the axial limiting ring and the honeycomb ring. The second working condition is the engine emergency shutdown condition. A systematic thermo-mechanical coupling failure assessment method is established. The load spectrum is applied to the finite element model to obtain the deformation assessment parameters of the axial limiting ring. Based on the failure judgment criteria, it is determined whether the axial limiting ring meets the safety requirements. A multi-objective optimization process is established for the system. The opening length and cross-sectional width of the axial limiting ring are used as design variables, and the thermo-mechanical coupling failure assessment method is used as the objective constraint function. A response surface model is used to establish a multi-objective optimization function, and a genetic algorithm is used to solve the multi-objective optimization function to find the opening length and cross-sectional width of the axial limiting ring that minimize the multi-objective optimization function, which is taken as the optimal solution for the axial limiting ring.

2. The axial limiting ring deformation optimization design method according to claim 1, characterized in that, The oblique angle is an acute angle.

3. The axial limiting ring deformation optimization design method according to claim 1, characterized in that, The constitutive model of the Chaboche kinematic strengthening material is as follows: ， in, For the material's yield strength, For equivalent plastic strain, To enhance the modulus, To enhance the modulus attenuation rate, n is set to 3; The model parameters were obtained by fitting the stress-plastic strain curve of a uniaxial monotonic tensile test of a standard specimen of an axial retaining ring material.

4. The axial limiting ring deformation optimization design method according to claim 1, characterized in that, The deformation evaluation parameters include: the equivalent plastic strain rate of the axially restraining ring. The percentage of unit volume undergoing plastic deformation (R), and the radial gap between the axial limiting ring and the honeycomb ring after cyclic load deformation. And the radial clearance between the axial limiting ring and the honeycomb ring under the second working condition. ; The failure determination criteria are as follows: Less than the preset strain rate safety threshold, R is less than the preset volume percentage safety threshold, Greater than zero Greater than zero.

5. The axial limiting ring deformation optimization design method according to claim 4, characterized in that, The equivalent plastic strain rate Calculated using the following formula: in, , Let N be the plastic strain of the axial retaining ring after the Nth and N+1th cyclic loading, where N is the cycle number of the first working condition set in the system operation. =1; The volume ratio R of the unit undergoing plastic deformation is calculated using the following formula: in, Let be the unit volume of the axial retaining ring after the Nth cyclic loading when plastic deformation occurs. This refers to the total volume of the axial limiting ring; The radial gap between the axial limiting ring and the honeycomb ring after cyclic load deformation Calculated using the following formula: in, The diameter of the axial limiting ring after deformation under the Nth cycle of load. This is the initial diameter of the honeycomb ring clamp.

6. The axial limiting ring deformation optimization design method according to claim 5, characterized in that, The diameter of the axial limiting ring after deformation under the Nth cyclic load Determined in the following ways: Obtain the coordinate values ​​(x1, y1), (x2, y2), and (x3, y3) of points A, B, and C on the axial limiting ring after deformation under the Nth cyclic load; where A is the point with an acute angle of chamfer on the inner diameter of the axial limiting ring, B is the point with the maximum radial residual deformation of the inner diameter of the axial limiting ring under the Nth cyclic load, and C is the node located no more than three nodes away from point B along the circumferential direction; Substitute the coordinates of the three points into the formula. Calculate the values ​​of a, b, and c; According to the formula Calculate diameter The Right now .

7. The axial limiting ring deformation optimization design method according to claim 4, characterized in that, Radial clearance between the axial limiting ring and the honeycomb ring under the second working condition Calculated using the following formula: in, This represents the radial displacement of the honeycomb ring under the second operating condition. This represents the radial displacement of the axial limiting ring under the second operating condition. This represents the initial radial gap between the axial limiting ring and the honeycomb ring.

8. The axial limiting ring deformation optimization design method according to claim 1, characterized in that, The response surface model is: Where m=2, This refers to the opening length of the axial limiting ring. The width of the cross-section of the axial limiting ring. , , These are the fitting parameters for the response surface model.

9. The axial limiting ring deformation optimization design method according to claim 4, characterized in that, The multi-objective optimization function is: in, , , , These are the weighting coefficients, and .

10. An axial limiting ring deformation optimization design system, used to implement the method described in any one of claims 1-9, characterized in that, The system includes: The 3D finite element model building module is used to build a 3D finite element model of the system, including the turbine casing, axial limiting ring, turbine guide, and honeycomb ring. The material constitutive determination module is used to simulate the stress-strain variation of the axially confined ring using the Chaboche kinematic strengthening material constitutive model. The load spectrum determination module is used to determine the thermo-mechanical load spectrum for deformation analysis of the axial retaining ring and establish a loading method for thermo-mechanical coupled cyclic load spectrum. The loading method includes a first-condition cyclic load spectrum loading and a second-condition load loading. The first-condition cyclic load spectrum loading sequentially includes: applying the axial force generated by the internal flow under the peak temperature state of the transient temperature field under the first-condition load; applying the axial force generated by the internal flow under the peak temperature state of the transient temperature field under the first-condition load and a nonlinear transient thermal simulation temperature field; applying the nonlinear transient thermal simulation temperature field generated by the internal flow under the peak temperature state of the transient temperature field under the first-condition load, without applying the axial force; and applying only room temperature. The second-condition load loading is used to evaluate the radial fit clearance between the axial retaining ring and the honeycomb ring. The thermo-mechanical coupling failure assessment module is used to apply the load spectrum to the finite element model, obtain the deformation assessment parameters of the axial limiting ring, and determine whether the axial limiting ring meets the safety requirements according to the failure judgment criteria. The multi-objective optimization module is used to establish a multi-objective optimization function with the opening length and cross-sectional width of the axial restraint ring as design variables, the thermo-mechanical coupling failure assessment method as the objective constraint function, and a response surface model. The module then uses a genetic algorithm to solve the multi-objective optimization function and seeks the opening length and cross-sectional width of the axial restraint ring that minimize the multi-objective optimization function, which are then taken as the optimal solution for the axial restraint ring.

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