Method and apparatus for life prediction of repaired turbine blades for liquid rocket engines

Abstract

The application provides a liquid rocket engine repaired turbine blade life prediction method and device, relates to the life prediction technical field of the repaired turbine blade, and comprises the following steps: obtaining a target test piece to carry out cladding repair; material performance test of the repaired target test piece obtains a material performance parameter set of the liquid rocket engine repaired turbine blade at different temperature points and under different strain amplitudes; a constitutive model of the repaired turbine blade is determined based on the material performance parameter set and a hardening model combining Chaboche follow-up hardening and Voce nonlinear isotropic hardening; working cycle simulation of the repaired turbine blade is carried out according to the constitutive model, stress and strain data of the turbine blade at a dangerous point position are obtained, cumulative damage of the turbine blade in the operation of the liquid rocket engine is determined based on the stress and strain data, and then the cycle life of the turbine blade is calculated; and the technical problem that the safety of the liquid rocket application is affected due to unknown life of the repaired turbine blade is relieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of life prediction of repaired turbine blades, in particular to a life prediction method and device for repaired turbine blades of a liquid rocket engine. BACKGROUND

[0002] The turbine blade is an important structural part of the liquid rocket engine, and its service environment is complex. It not only has a sustained temperature load and an aerodynamic load, but also a centrifugal load generated by high-speed rotation of the turbine, and is prone to fatigue fracture damage. Since the blade is made of precision casting process, the process is complex and the manufacturing cycle is long, so replacing the damaged blade directly with a new blade will result in high cost. Laser cladding repair has become an important means for repairing damage due to its low cost and short manufacturing cycle.

[0003] However, in the field of liquid rocket engines, the life of the repaired turbine blade has not been considered, and the application life of the repaired turbine blade cannot be guaranteed. SUMMARY

[0004] The purpose of the present application is to provide a life prediction method and device for repaired turbine blades of a liquid rocket engine, so as to alleviate the technical problem that the life of the repaired turbine blade is unknown, thereby affecting the safety of the liquid rocket application.

[0005] In a first aspect, the present application provides a life prediction method for repaired turbine blades of a liquid rocket engine, comprising:

[0006] Obtaining a target test piece for characterizing an un-repaired turbine blade of a liquid rocket engine, and performing cladding repair on the target test piece;

[0007] Performing a material performance test on the repaired target test piece to obtain a set of material performance parameters of the repaired turbine blade of the liquid rocket engine at different temperature points and different strain amplitudes;

[0008] Based on the set of material performance parameters and a hardening model combining Chaboche follow-up hardening and Voce nonlinear isotropic hardening, a constitutive model of the repaired turbine blade is determined by a particle swarm optimization algorithm, wherein the constitutive model is used to simulate the stress-strain response of the repaired turbine blade under cyclic loading;

[0009] Based on the constitutive model, a working cycle simulation is performed on the repaired turbine blade to obtain stress-strain data of the repaired turbine blade at a dangerous point position;

[0010] Based on the stress-strain data, the cumulative damage of the repaired turbine blade in the operation of the liquid rocket engine is calculated, and the cycle life of the repaired turbine blade is predicted.

[0011] Further, the step of obtaining the target test piece for characterizing the un-repaired turbine blade of the liquid rocket engine includes:

[0012] Performing finite element simulation on the un-repaired turbine blade of the liquid rocket engine to obtain stress values of stress gradient and dangerous point position of the un-repaired turbine blade;

[0013] According to the material performance test condition, a first test piece is determined which is consistent with the stress values of stress gradient and dangerous point position of the un-repaired turbine blade;

[0014] Performing removal processing on a preset area range of the dangerous point position of the first test piece;

[0015] Determining a heat dissipation base based on the size of the first test piece and the cladding test result;

[0016] Assembling the first test piece with the heat dissipation base to obtain the target test piece of the un-repaired turbine blade.

[0017] Further, the step of performing laser cladding repair on the target test piece includes:

[0018] Selecting the base material corresponding to the target test piece, and under the action of target laser cladding process parameters, performing laser cladding repair on the preset area range of the dangerous point position of the target test piece; wherein the target laser cladding process parameters are determined by orthogonal test results.

[0019] Further, the step of performing material performance test on the repaired target test piece to obtain a set of material performance parameters of the repaired turbine blade of the liquid rocket engine under different temperature points and different strain amplitudes includes:

[0020] Performing uniaxial tensile test on the repaired target test piece to obtain stress-strain curves of the repaired turbine blade under different temperature points;

[0021] Performing cyclic loading test on the repaired target test piece to obtain stable cyclic hysteresis curves of the repaired turbine blade under different strain amplitudes.

[0022] Further, based on the set of material performance parameters and the hardening model combining Chaboche follow-up hardening and Voce nonlinear isotropic hardening, the step of determining the constitutive model of the repaired turbine blade by particle swarm optimization algorithm includes:

[0023] The target parameters in a hardening model obtained by combining Chaboche follow-up hardening and Voce nonlinear isotropic hardening are fitted by using a particle swarm optimization algorithm, and a constitutive model of the repaired turbine blade is constructed by using the set of material performance parameters.

[0024] Further, the stress and strain data of the dangerous point position of the repaired turbine blade are obtained by performing a working cycle simulation on the repaired turbine blade based on the constitutive model, and the stress and strain data of the dangerous point position of the repaired turbine blade are obtained by performing a working cycle simulation on the repaired turbine blade based on the constitutive model.

[0025] The surface gas temperature, pressure and convective heat transfer coefficient of the repaired turbine blade are obtained by performing a flow field simulation on the repaired turbine blade.

[0026] The temperature distribution of the repaired turbine blade is obtained by performing a thermal analysis on the repaired turbine blade by taking the surface gas temperature and the convective heat transfer coefficient as thermal loads.

[0027] The stress and strain data corresponding to the dangerous point position of the repaired turbine blade are obtained by performing a three-dimensional finite element structure analysis on the repaired turbine blade based on the constitutive model under the temperature distribution, the pressure and a preset rotating speed.

[0028] Further, the cumulative damage of the repaired turbine blade in the operation of the liquid rocket engine is calculated based on the stress and strain data, and the cycle life of the repaired turbine blade is estimated.

[0029] The low-cycle fatigue damage and the ratcheting damage of the repaired turbine blade are calculated based on the stress and strain data.

[0030] The cumulative damage of the repaired turbine blade in the operation of the liquid rocket engine is obtained by adding the low-cycle fatigue damage and the ratcheting damage.

[0031] The cycle life of the repaired turbine blade is determined based on the time when the cumulative damage reaches a preset cumulative damage threshold.

[0032] In a second aspect, the embodiments of the present application also provide a life estimation device for a repaired turbine blade of a liquid rocket engine, which comprises:

[0033] A repair module acquires a target test piece for representing an unrepaired turbine blade of a liquid rocket engine, and performs cladding repair on the target test piece.

[0034] A test module performs a material performance test on the repaired target test piece, and obtains a set of material performance parameters of the repaired turbine blade of the liquid rocket engine at different temperature points and different strain amplitudes.

[0035] A determining module determines a constitutive model of the repaired turbine blade based on the set of material performance parameters and a hardening model combining Chaboche kinematic hardening and Voce nonlinear isotropic hardening through a particle swarm optimization algorithm, wherein the constitutive model is used to simulate stress-strain response of the repaired turbine blade under cyclic loading;

[0036] A simulation module simulates a working cycle of the repaired turbine blade based on the constitutive model to obtain stress-strain data of the repaired turbine blade at a dangerous point position;

[0037] A prediction module calculates cumulative damage of the repaired turbine blade in the operation of the liquid rocket engine based on the stress-strain data and predicts a cycle life of the repaired turbine blade.

[0038] In a third aspect, an embodiment provides an electronic device, including a memory and a processor, the memory storing a computer program executable on the processor, and the processor implements steps of the method in any of the preceding embodiments when executing the computer program.

[0039] In a fourth aspect, an embodiment provides a machine-readable storage medium storing machine-executable instructions, the machine-executable instructions causing a processor to implement steps of the method in any of the preceding embodiments when invoked and executed by the processor.

[0040] The embodiments of the present application provide a life prediction method and device for a repaired turbine blade of a liquid rocket engine. First, a target test piece of an unrepaired turbine blade of a liquid rocket engine is designed and constructed, the target test piece is subjected to cladding repair processing, and then material performance testing is performed to obtain material performance parameters of the repaired turbine blade of the liquid rocket engine. Target parameters of a hardening model combining Chaboche kinematic hardening and Voce nonlinear isotropic hardening are fitted based on the material performance parameters, and a constitutive model capable of representing stress-strain response of the repaired turbine blade under cyclic loading is obtained. Then, working cycle simulation is performed on the repaired turbine blade based on the constitutive model capable of representing stress-strain response of the repaired turbine blade under cyclic loading, to obtain relatively accurate stress-strain data of the repaired turbine blade at a dangerous point position. According to the stress-strain data, cumulative damage of the repaired turbine blade applied to the liquid rocket engine can be predicted, and the cycle life of the repaired turbine blade can be predicted, so as to ensure safety and reliability of the liquid rocket engine to which the repaired turbine blade is applied.

[0041] Other features and advantages of the present application will be set forth in the descriptions that follow, and in part will be apparent from the description, or can be learned by practice of the application. The purposes and other advantages of the present application will be realized and attained by the structures particularly pointed out in the description and the appended drawings.

[0042] In order to make the above objectives, features and advantages of the present application more apparent, the following will describe a preferred embodiment in detail, and the accompanying drawings will be described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0044] Figure 1 A flow chart of a life prediction method of a repaired turbine blade of a liquid rocket engine is provided for the embodiments of the present application;

[0045] Figure 2 A flow chart of a target test piece determination method is provided for the embodiments of the present application;

[0046] Figure 3 A three-dimensional finite element structure analysis model of a repaired turbine blade is provided for the embodiments of the present application;

[0047] Figure 4 A schematic diagram of a target test piece is provided for the embodiments of the present application;

[0048] Figure 5 A functional module schematic diagram of a life prediction device of a repaired turbine blade of a liquid rocket engine is provided for the embodiments of the present application;

[0049] Figure 6 A hardware architecture schematic diagram of an electronic device is provided for the embodiments of the present application. DETAILED DESCRIPTION

[0050] In order to make the objectives, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the present application will be described clearly and completely with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0051] The inventor has found that there is currently a lack of life prediction for repaired turbine blades, which makes it difficult to fully guarantee the application reliability of liquid rocket engines.

[0052] Therefore, the life prediction method and device for the repaired turbine blades of the liquid rocket engine provided by the embodiments of the present application can predict the life of the repaired turbine blades, and replace them in time before the life expires, so as to guarantee the safety and reliability of the liquid rocket engine.

[0053] To make the embodiments of the present application more comprehensible, first, a life prediction method for the repaired turbine blades of a liquid rocket engine is described in detail, which can be applied to intelligent control devices such as host computers, servers, and controllers.

[0054] Figure 1 The life prediction method for the repaired turbine blades of the liquid rocket engine provided by the embodiments of the present application is shown in the flowchart.

[0055] Referring to Figure 1 The method mainly includes the following steps:

[0056] In step S102, a target test piece for representing an unrepaired turbine blade of a liquid rocket engine is obtained, and the target test piece is subjected to cladding repair.

[0057] Here, the target test piece is designed and constructed based on the unrepaired turbine blade of the liquid rocket engine, and after the cladding repair operation, the repaired turbine blade of the liquid rocket engine can be represented, so as to obtain the material performance test results of the repaired turbine blade.

[0058] In step S104, material performance tests are performed on the repaired target test piece, and a set of material performance parameters of the repaired turbine blade of the liquid rocket engine at different temperature points and different strain amplitudes is obtained.

[0059] The set of material performance parameters at different temperature points and different strain amplitudes can be understood as a material mechanical property parameter curve corresponding to different temperatures and different strain amplitudes, so as to represent the results of the material performance tests of the repaired turbine blade.

[0060] In step S106, based on the set of material performance parameters and the hardening model combining Chaboche follow-up hardening and Voce nonlinear isotropic hardening, a constitutive model of the repaired turbine blade is determined by a particle swarm optimization algorithm.

[0061] The Chaboche model is a multi-component nonlinear follow-up hardening model, and is mainly used for simulating the cyclic hardening or softening behavior of a material in simulation analysis. The constitutive model in the embodiment is used for simulating the stress-strain response of the repaired turbine blade under cyclic loading. The target parameters of the constitutive model are fitted based on the set of material performance parameters obtained from the material performance test of the foregoing embodiment, so that the corresponding constitutive model of the repaired turbine blade can be accurately determined, so as to estimate the life of the repaired turbine blade in the subsequent step.

[0062] In step S108, the working cycle simulation of the repaired turbine blade is performed based on the constitutive model, and the stress-strain data of the repaired turbine blade at the dangerous point position is obtained.

[0063] Here, the stress-strain response of the repaired turbine blade under cyclic loading is considered, and the working cycle simulation of the repaired turbine blade is performed, so that more accurate stress-strain data can be obtained.

[0064] In step S110, the cumulative damage of the repaired turbine blade in the operation of the liquid rocket engine is calculated based on the stress-strain data, and the cycle life of the repaired turbine blade is estimated.

[0065] It should be noted that the cumulative damage of the repaired turbine blade applied to the liquid rocket engine is predicted based on the stress-strain data at the dangerous point position, i.e., the position most prone to damage, to estimate the cycle life of the repaired turbine blade, so as to ensure the application reliability of the turbine blade.

[0066] In the preferred embodiment in actual application, first, a target test piece of an un-repaired turbine blade of a liquid rocket engine is designed and constructed, the target test piece is subjected to cladding repair processing, and then a material performance test is performed to obtain material performance parameters of a repaired turbine blade of the liquid rocket engine; target parameters of a hardening model combining Chaboche follow-up hardening and Voce nonlinear isotropic hardening are fitted based on the material performance parameters, so as to obtain a constitutive model capable of representing the stress-strain response of the repaired turbine blade under cyclic loading; then, working cycle simulation of the repaired turbine blade is performed based on the constitutive model capable of representing the stress-strain response of the repaired turbine blade under cyclic loading, so as to obtain more accurate stress-strain data of the repaired turbine blade at the dangerous point position; the cumulative damage of the repaired turbine blade applied to the liquid rocket engine can be predicted based on the stress-strain data, and the cycle life of the repaired turbine blade is estimated, so as to ensure the safety and reliability of the liquid rocket engine to which the repaired turbine blade is applied.

[0067] In some embodiments, the construction design of the target test piece in step S102 can be achieved by the following steps to more accurately characterize the un-repaired turbine blade of the liquid rocket engine, specifically comprising:

[0068] Step 1.1), finite element simulation is performed on the un-repaired turbine blade of the liquid rocket engine to obtain the stress gradient of the un-repaired turbine blade and the stress value at the dangerous point position.

[0069] First, finite element simulation is performed on the un-repaired turbine blade of the liquid rocket engine to obtain the stress value and stress gradient at each position of the turbine blade, and the position with the maximum stress value is identified as the dangerous point position.

[0070] Step 1.2), according to the material performance test conditions, determine the first test piece which is consistent with the stress gradient of the un-repaired turbine blade and the stress value at the dangerous point position;

[0071] Here, the material performance test conditions can be understood as the equipment situation for subsequent material performance test; according to the equipment type, clamp size and other equipment information for subsequent implementation of material performance test, the shape and size of the first test piece (cladding test piece) are designed, such as plate or rod, etc.; then the first test piece is subjected to finite element simulation test, so as to compare the stress value at the dangerous point position of the first test piece with the stress value at the dangerous point position of the un-repaired turbine blade, and compare the stress gradient at each position of the first test piece with the stress gradient at each position of the un-repaired turbine blade; if the stress value at the dangerous point position and the gradient value at each position are consistent, the first test piece is qualified; if the stress value at the dangerous point position is inconsistent, or the stress gradient at any position is inconsistent, the first test piece is unqualified, and the design of the first test piece is re-optimized and improved.

[0072] Step 1.3), the preset area range of the dangerous point position of the first test piece is removed.

[0073] For small area damage defects such as cracks on the surface of the turbine blade of nickel-based superalloy, the damage area is usually removed by machining, and then repaired. Therefore, after obtaining the reasonably designed first test piece, the crack size is obtained by means of penetration detection and other methods on the actual un-repaired turbine blade, and the preset area range of the dangerous point position is removed as the subsequent cladding repair area. Wherein, the preset area range can be set according to the crack size.

[0074] It should be noted that the cladding area is generally set at one end of the first test piece, and the dangerous point position is located in the cladding area. First, the preset area range including the dangerous point position is removed by turning or other methods, and then the subsequent cladding repair is performed on the preset area range.

[0075] Step 1.4), determining the heat dissipation base based on the size of the first test piece and the cladding test results.

[0076] Since the actual size of the turbine blade is small in practice, the size of the equivalent design first test piece is also small, and poor heat dissipation may occur during laser cladding. Therefore, based on the first test piece, a laser cladding heat dissipation base is designed based on the size of the first test piece, and the effectiveness of the heat dissipation base is verified by whether the first test piece deforms after the cladding test. It can be understood that if the heat dissipation base is designed in compliance, the first test piece does not deform after the cladding test (the test can be a simulation test), otherwise.

[0077] Step 1.5), assembling the first test piece and the heat dissipation base to obtain the target test piece of the unrepaired turbine blade.

[0078] The target test piece is used to characterize the unrepaired turbine blade, Figure 4 as shown in a target test piece; wherein the cladding test piece is equivalent to the first test piece, and the heat dissipation base and the cladding region of the cladding test piece are connected at the end;

[0079] Exemplarily, see Figure 2 Another target test piece determination method is shown in order to obtain a target test piece design, which specifically comprises:

[0080] Finite element simulation of liquid rocket engine turbine blades to obtain turbine blade dangerous point position; according to the dangerous point position and the stress gradient change, the shape and size of the test piece are designed; judge whether the stress at the dangerous point of the test piece finite element simulation is consistent with the dangerous point of the blade; if not, return to the step of designing the shape and size of the test piece according to the dangerous point position and the stress gradient change; if consistent, remove the cladding region of the test piece dangerous point position according to the turbine blade crack size; laser cladding heat dissipation base design; validity verification of heat dissipation base, judge whether the heat dissipation base is effective; if not reasonable, repeat the step of laser cladding heat dissipation base design; if reasonable, assemble the test piece and the heat dissipation base, complete the laser cladding repair test piece overall design.

[0081] On the basis of the foregoing embodiments, the target test piece performs the operation of laser cladding repair in step S102, which comprises:

[0082] Step 2.1), selecting the base material corresponding to the target test piece, and under the action of the target laser cladding process parameters, the preset region range of the dangerous point position in the target test piece is repaired by laser cladding.

[0083] Wherein, the target laser cladding process parameters are determined by orthogonal test results. Orthogonal test is designed by considering the type of laser cladding equipment, cladding materials, etc.

[0084] On the basis of the designed target test piece, the preset area range of the dangerous point position is repaired by laser cladding. In order to avoid the difference of cladding effect caused by different materials, the same substrate material as the target test piece is selected for cladding, such as high-temperature alloy powder material. At the same time, according to the type of equipment for performing laser cladding operation, the size of the target test piece and the characteristics of the substrate material, an orthogonal test is designed to determine the optimal laser cladding process parameters, including laser power, powder feeding rate, spot size and scanning speed. The quality of the cladding result can be determined by the cladding layer morphology and porosity.

[0085] In some embodiments, step S104 is further implemented by the following steps to obtain the material performance test results for characterizing the repaired turbine blade, specifically including:

[0086] Step 3.1), uniaxial tensile test is performed on the repaired target test piece to obtain the stress-strain curve of the repaired turbine blade at different temperature points.

[0087] Step 3.2), cyclic loading test is performed on the repaired target test piece to obtain the stable cyclic hysteresis curve of the repaired turbine blade at a certain preset temperature point corresponding to different strain amplitudes.

[0088] After laser cladding treatment is completed, in order to obtain material performance parameters, uniaxial tensile test and cyclic loading test are carried out on the test piece after cladding treatment. In order to reduce the influence of test error, each of the above two test steps is performed three times. The uniaxial tensile test can be understood as directly stretching at different temperature points until the stress-strain curve is obtained. From the stress-strain curve, the elastic modulus, tensile strength, yield strength, elongation after fracture and reduction of area of the repaired material at different temperature points can be obtained. The cyclic loading test can be understood as cyclic loading test based on different strain amplitudes at a certain preset temperature point, and the stable cyclic curve is obtained. From the stable cyclic curve, the yield strength, cyclic stiffness and hardening parameters can be obtained.

[0089] On the basis of the foregoing embodiments, it can be known that the set of material performance parameters is two curves obtained by two material performance test operations, which can characterize the set of material performance parameters of the repaired turbine blade at different temperature points and different strain amplitudes. In step S104, the set of material performance parameters and the hardening model are combined to determine the constitutive model of the repaired turbine blade, including:

[0090] Step 4.1), considering the influence of the ratchet effect, the set of material performance parameters is used to fit the target parameters in the hardening model obtained by combining Chaboche follow-up hardening and Voce function nonlinear isotropic hardening by particle swarm optimization algorithm, and the constitutive model of the repaired turbine blade is constructed.

[0091] where the nonlinear isotropic hardening of the Voce function is a specific type of isotropic hardening.

[0092] Exemplarily, the Chaboche kinematic hardening model is based on the Von Mises yield criterion, and the yield function is as follows:

[0093]

[0094] where, is the stress tensor, is the back stress tensor, representing the center of the yield surface; is the deviatoric stress tensor, is the deviatoric back stress tensor, representing the center of the yield surface in the deviatoric stress space; represents the size of the yield surface.

[0095] The Chaboche hardening model is a superposition of several Armstrong-Frederick (A-F) nonlinear hardening models, and the expression is as follows:

[0096]

[0097]

[0098] where M is the number of superimposed hardening models, and are parameters related to the material and temperature. and are part of the target parameters to be fitted in the constitutive model.

[0099] Based on the A-F evolution law, when in a strain-controlled steady cycle, the following formula exists:

[0100]

[0101] For the size of the yield surface, according to the isotropic hardening criterion, it can be shown as follows:

[0102]

[0103] where, is the yield stress, is the plastic strain tensor, , and b are another part of the target parameters to be fitted in the constitutive model.

[0104] The material performance parameter set obtained by material test, i.e., stress-strain curves at different temperature points and stable cyclic hysteresis curves at different strain amplitudes at preset temperature points, are used to fit the target parameters in the constitutive model through a particle swarm optimization algorithm , , , and b, specifically comprising:

[0105] The stress-strain curve is first converted to a plastic segment curve in the stress-plastic strain coordinate, and then the plastic segment curve is divided into n+1 segments, and the slope of the secant line of each segment of the plastic segment curve is calculated, denoted as Based on the plastic segment curve, the initial values of and can be obtained; wherein the strengthening modulus is the difference between the slopes of the secant lines of every two adjacent segments of the plastic segment curve, and the decay rate of the strengthening modulus is the reciprocal of the plastic strain of the plastic segment curve.

[0106] Since the abscissa strain of the stress-strain curve is the total strain including the elastic strain and the plastic strain, the stress-plastic strain graph is obtained by subtracting the elastic strain from the total strain; based on the stress-plastic strain graph, the initial values of , and b can be obtained; wherein the stress-plastic strain graph (curve) is divided into two segments, the first segment is a small strain segment with large curvature change, and the second segment is a large strain segment with approximately constant curvature. The tangent or secant slope of the second segment is taken. + is the intersection of the above secant line extended to the σ axis. is the initial tangent or secant slope when the plastic strain begins to occur.

[0107] Based on the initial values of the above five target parameters, the initial constitutive model of the repaired turbine blade is determined; based on the initial constitutive model, the corresponding predicted cyclic hysteresis curve can be determined, and the predicted cyclic hysteresis curve is compared with the cyclic hysteresis curve obtained by the material performance test in the foregoing embodiment step; it is judged whether the difference between the predicted cyclic hysteresis curve and the cyclic hysteresis curve obtained by the test meets the requirement that the difference is within the preset difference threshold range of 5%;

[0108] If the requirement is met, the target parameters at this time, and the constitutive model corresponding to the target parameters, are the final optimized target parameters and constitutive model;

[0109] If the requirement is not met, the particle swarm optimization algorithm is used for parameter optimization, the speed and position of the particle are updated through iteration, and the two objectives in the particle swarm optimization algorithm fitness function are cooperatively optimized to minimize the overall error; wherein the particle swarm optimization algorithm fitness function is the point-to-point deviation and the difference in hysteresis loop area between the predicted cyclic hysteresis curve and the cyclic hysteresis curve obtained by experiment; it can be understood that the two objectives to be cooperatively optimized are the point-to-point deviation and the difference in hysteresis loop area between the cyclic hysteresis curves; return to execute the step of judging whether the difference between the predicted cyclic hysteresis curve and the cyclic hysteresis curve obtained by experiment meets the requirement of being within the preset difference threshold range of 5%;

[0110] It should be noted that when both of the two objectives to be cooperatively optimized are reduced within the preset difference threshold range of 5%, the difference between the predicted cyclic hysteresis curve and the cyclic hysteresis curve obtained by experiment meets the requirement of being within the preset difference threshold range of 5%, and the iterative optimization operation stops.

[0111] In some embodiments, step S108 introduces the influence of the constitutive model to perform working cycle simulation on the repaired turbine blade, so as to obtain more accurate stress and strain data. This can be achieved by the following steps, including:

[0112] Step 4.1), flow field simulation is performed on the repaired turbine blade to obtain the temperature, pressure and convective heat transfer coefficient of the surface gas of the repaired turbine blade.

[0113] Step 4.2), the temperature and convective heat transfer coefficient of the surface gas are taken as thermal load to perform thermal analysis on the repaired turbine blade to obtain the temperature distribution of the repaired turbine blade.

[0114] Step 4.3), based on the constitutive model, three-dimensional finite element structure analysis is performed on the repaired turbine blade under the action of the temperature distribution, pressure and preset rotating speed to obtain the stress and strain data corresponding to the dangerous point position of the repaired turbine blade. The preset rotating speed can be understood as a specific rotating speed value corresponding to the repaired turbine blade to be life estimated according to its model, or the engine model to which it is applied.

[0115] On the basis of the temperature distribution obtained by the foregoing step of thermal analysis, the constitutive model is introduced, and three-dimensional finite element structure analysis of the repaired turbine blade is performed again; considering the cyclic symmetry of the turbine, one blade and part of the disc are taken for simulation calculation. The nodes on the hub center line are subjected to radial constraint to constrain the circumferential displacement of the nodes within the radius range of the center axis of the downstream end surface, the nodes on the hub circumferential surface are subjected to coupling constraint to obtain the cyclic symmetry boundary, and the circumferential displacement of the nodes on the disc boss circumferential surface is constrained. The analysis model is as shown in Figure 3 The dangerous point position and equivalent stress cloud diagram of the blade are obtained through simulation, and then the stress and strain data of the dangerous point position are extracted.

[0116] On the basis of the foregoing embodiments, step S110 estimates the service life of the repaired turbine blade applicable to the liquid rocket engine based on the stress-strain data of the dangerous point position where the abnormality is most likely to occur, including:

[0117] Step 5.1), based on the stress-strain data, respectively calculates the low-cycle fatigue damage and the ratcheting damage of the repaired turbine blade.

[0118] For the engine repeated start-stop working process, the local strain analysis method is used for turbine low-cycle fatigue analysis, and the Manson-Coffin (referred to as M-C) theory is used to establish a strain-life prediction model, and the general M-C formula is as follows:

[0119]

[0120] wherein, is the total strain, is the total strain range, is the elastic strain, is the elastic strain range, is the plastic strain range, is the low-cycle fatigue life cycle number; is the elastic modulus of the material, , , , is the fatigue performance parameter of the material.

[0121] Since the crack initiation and propagation of the repaired turbine blade in actual application is also affected by the principal stress, in order to further more accurately estimate the service life of the repaired turbine blade, according to the fatigue theory proposed by Smith et al., the influence of the principal stress is considered, and the above M-C formula is modified by SWT to obtain the strain-life formula as follows:

[0122]

[0123] Under the action of cyclic thermal load and centrifugal load, the thermal structural response of the turbine has r strain amplitudes, and the life under each strain amplitude is , in a working cycle, the low-cycle fatigue damage can be obtained as follows:

[0124]

[0125] The ratcheting damage can be defined as a function of the cumulative plastic tensile strain:

[0126]

[0127] wherein, is the residual strain after the cycle, is the initial strain of the cycle, represents the ultimate strain of the material.

[0128] Step 5.2), the low-cycle fatigue damage and the ratcheting damage are added to obtain the cumulative damage of the repaired turbine blade in the operation of the liquid rocket engine.

[0129] Assuming that various types of damage are linearly accumulated, the total damage in one cycle is:

[0130]

[0131]

[0132] wherein, D is the cumulative damage after a plurality of cycles, i is the cycle number, and the cycle life is , that is, the cumulative damage formula can be understood as the cycle life of the repaired turbine blade after i cycles is , and the cumulative damage thereof is D.

[0133] Step 5.3), based on the time when the cumulative damage reaches the preset cumulative damage threshold, the cycle life of the repaired turbine blade is determined.

[0134] According to the Palmgren-Miner linear cumulative damage rule, when the cumulative damage reaches the preset cumulative damage threshold, the repaired turbine blade structure will be damaged, and based on this, the cycle life is calculated as . Wherein, the preset cumulative damage threshold is selected as 1.

[0135] The embodiment of the present application first designs a laser cladding repair test piece, then selects appropriate process parameters for laser cladding, and then mechanically processes the surface of the test piece after laser cladding to make it have good surface gloss. On this basis, tensile and cyclic loading tests are carried out on the repaired test piece to obtain material performance parameters, and then the particle swarm optimization algorithm is used to fit the parameters involved in the constitutive model. Finally, multi-cycle turbine working process simulation is carried out to obtain the stress-strain response of the turbine blade after repair, and the damage model is substituted into the damage model to obtain the life of the repaired turbine based on the linear cumulative damage criterion.

[0136] In some embodiments, as shown in Figure 5 the embodiment of the present application provides a life prediction device for a repaired turbine blade of a liquid rocket engine, comprising:

[0137] A repair module acquires a target test piece for representing an unrepaired turbine blade of a liquid rocket engine, and performs cladding repair on the target test piece.

[0138] a test module configured to perform a material performance test on the target test piece after repair to obtain a set of material performance parameters of the repaired turbine blade of the liquid rocket engine at different temperature points and different strain amplitudes;

[0139] a determination module configured to determine a constitutive model of the repaired turbine blade based on the set of material performance parameters and a hardening model combining Chaboche kinematic hardening and Voce nonlinear isotropic hardening, by a particle swarm optimization algorithm, wherein the constitutive model is used to simulate stress-strain responses of the repaired turbine blade under cyclic loading;

[0140] a simulation module configured to perform a working cycle simulation on the repaired turbine blade based on the constitutive model to obtain stress-strain data of the repaired turbine blade at a dangerous point position;

[0141] an estimation module configured to calculate cumulative damage of the repaired turbine blade in operation of the liquid rocket engine based on the stress-strain data, and estimate a cycle life of the repaired turbine blade.

[0142] Further, the repair module is further configured to perform finite element simulation on an un-repaired turbine blade of the liquid rocket engine to obtain a stress gradient of the un-repaired turbine blade and a stress value at a dangerous point position of the un-repaired turbine blade; determine a first test piece consistent with the stress gradient of the un-repaired turbine blade and the stress value at the dangerous point position of the un-repaired turbine blade according to a material performance test condition; perform removal processing on a preset area range of the dangerous point position of the first test piece; determine a heat dissipation base based on a size of the first test piece and a cladding test result; and assemble the first test piece and the heat dissipation base to obtain a target test piece of the un-repaired turbine blade.

[0143] Further, the repair module is further configured to select a base material corresponding to the target test piece, and perform laser cladding repair on a preset area range of the dangerous point position of the target test piece under the action of target laser cladding process parameters, wherein the target laser cladding process parameters are determined by orthogonal test results.

[0144] Further, the test module is further configured to perform uniaxial tensile test on the target test piece after repair to obtain stress-strain curves of the repaired turbine blade at different temperature points; and perform cyclic loading test on the target test piece after repair to obtain stable cyclic hysteresis curves of the repaired turbine blade at different strain amplitudes.

[0145] Further, the determining module is further configured to fit target parameters in a hardening model obtained by combining Chaboche afterloading hardening and Voce nonlinear isotropic hardening through a particle swarm optimization algorithm based on the material performance parameter set, and construct a constitutive model of the repaired turbine blade.

[0146] Further, the simulation module is further configured to perform flow field simulation on the repaired turbine blade to obtain temperature, pressure and convective heat transfer coefficient of surface gas of the repaired turbine blade, perform thermal analysis on the repaired turbine blade by taking the temperature of the surface gas and the convective heat transfer coefficient as thermal load to obtain temperature distribution of the repaired turbine blade, and perform three-dimensional finite element structure analysis on the repaired turbine blade based on the constitutive model under the temperature distribution, the pressure and a preset rotating speed to obtain stress and strain data corresponding to a dangerous point position of the repaired turbine blade.

[0147] Further, the estimation module is further configured to calculate low-cycle fatigue damage and ratcheting damage of the repaired turbine blade based on the stress and strain data respectively, add the low-cycle fatigue damage and the ratcheting damage to obtain cumulative damage of the repaired turbine blade in operation of the liquid rocket engine, and determine the cycle life of the repaired turbine blade based on a time when the cumulative damage reaches a preset cumulative damage threshold.

[0148] The electronic device provided in the embodiment can be, but is not limited to, a personal computer (PC), a notebook computer, a monitoring device, a server, and the like.

[0149] As an exemplary embodiment, refer to Figure 6 The electronic device 110 comprises a communication interface 111, a processor 112, a memory 113 and a bus 114, the processor 112, the communication interface 111 and the memory 113 are connected through the bus 114; the memory 113 is used for storing a computer program supporting the processor 112 to execute the above method, and the processor 112 is configured to execute the program stored in the memory 113.

[0150] The machine-readable storage medium mentioned herein can be any electronic, magnetic, optical or other physical storage device, and can contain or store information such as executable instructions, data, etc. For example, the machine-readable storage medium can be RAM (Random Access Memory), volatile memory, non-volatile memory, flash memory, storage drive (such as hard disk drive), any type of storage disk (such as optical disk, dvd, etc.), or similar storage medium, or combination thereof.

[0151] The non-volatile media can be a non-volatile memory, a flash memory, a storage drive (such as a hard disk drive), any type of storage disk (such as an optical disk, a DVD, etc.), or similar non-volatile storage media, or a combination thereof.

[0152] It can be understood that the specific operation methods of the function modules in the embodiments can refer to the detailed description of the corresponding steps in the above method embodiments, which will not be repeated here.

[0153] The computer readable storage medium provided in the embodiments of the present application stores a computer program, and the computer program code can implement the method described in any of the above embodiments when executed, and the specific implementation can refer to the method embodiments, which will not be repeated here.

[0154] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described system and device can refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0155] In addition, in the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0156] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0157] Finally, it should be noted that the above-described embodiments are merely specific embodiments of the present application, which are used to illustrate the technical solutions of the present application, but not to limit the present application, the protection scope of the present application is not limited thereto, although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art within the technical range disclosed by the present application, the technical solutions recorded in the foregoing embodiments can still be modified or easily thought of changes, or equivalent replacement of part of the technical features, and these modifications, changes or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be covered in the protection scope of the present application.

Claims

1. A method for life prediction of a repaired turbine blade of a liquid rocket engine, characterized in that, The method comprises the following steps: acquiring a target test piece for representing an un-repaired turbine blade of a liquid rocket engine, and performing laser cladding repair on the target test piece; performing material performance test on the repaired target test piece to obtain a set of material performance parameters of the repaired turbine blade of the liquid rocket engine at different temperature points and different strain amplitudes; determining a constitutive model of the repaired turbine blade based on the set of material performance parameters and a hardening model combining Chaboche kinematic hardening and Voce nonlinear isotropic hardening, by using a particle swarm optimization algorithm, wherein the constitutive model is used to simulate stress-strain response of the repaired turbine blade under cyclic loading; performing working cycle simulation on the repaired turbine blade based on the constitutive model to obtain stress-strain data of the repaired turbine blade at a dangerous point position; calculating cumulative damage of the repaired turbine blade in the operation of the liquid rocket engine based on the stress-strain data, and estimating the cycle life of the repaired turbine blade.

2. The method of claim 1, wherein, The step of acquiring a target test piece for representing an un-repaired turbine blade of a liquid rocket engine comprises: performing finite element simulation on the un-repaired turbine blade of the liquid rocket engine to obtain a stress gradient and a stress value at a dangerous point position of the un-repaired turbine blade; determining a first test piece that is consistent with the stress gradient and the stress value at the dangerous point position of the un-repaired turbine blade according to material performance test conditions; performing removal processing on a preset area range at the dangerous point position of the first test piece; determining a heat dissipation base based on the size of the first test piece and laser cladding test results; assembling the first test piece and the heat dissipation base to obtain the target test piece of the un-repaired turbine blade.

3. The method of claim 1, wherein, The step of performing laser cladding repair on the target test piece comprises: selecting a base material corresponding to the target test piece, and performing laser cladding repair on a preset area range at a dangerous point position of the target test piece under the action of target laser cladding process parameters, wherein the target laser cladding process parameters are determined by orthogonal test results.

4. The method of claim 1, wherein, The step of performing material performance test on the repaired target test piece to obtain a set of material performance parameters of the repaired turbine blade of the liquid rocket engine at different temperature points and different strain amplitudes comprises: performing uniaxial tensile test on the repaired target test piece to obtain stress-strain curves of the repaired turbine blade at different temperature points; performing cyclic loading test on the repaired target test piece to obtain stable cyclic hysteresis curves of the repaired turbine blade at different strain amplitudes.

5. The method of claim 1, wherein, The step of determining a constitutive model of the repaired turbine blade based on the set of material performance parameters and a hardening model combining Chaboche kinematic hardening and Voce nonlinear isotropic hardening, by using a particle swarm optimization algorithm, comprises: fitting target parameters in a hardening model obtained by combining Chaboche kinematic hardening and Voce nonlinear isotropic hardening, by using a particle swarm optimization algorithm, through the set of material performance parameters, to construct the constitutive model of the repaired turbine blade.

6. The method of claim 1, wherein, The step of simulating the working cycle of the repaired turbine blade based on the constitutive model to obtain stress and strain data of the repaired turbine blade at a dangerous point position comprises: simulating a flow field of the repaired turbine blade to obtain temperature, pressure and convective heat transfer coefficient of surface combustion gas of the repaired turbine blade; performing thermal analysis on the repaired turbine blade by taking the temperature of the surface combustion gas and the convective heat transfer coefficient as thermal load to obtain temperature distribution of the repaired turbine blade; performing three-dimensional finite element structural analysis on the repaired turbine blade based on the constitutive model, the temperature distribution, the pressure and a preset rotating speed to obtain stress and strain data corresponding to the dangerous point position of the repaired turbine blade.

7. The method of claim 1, wherein, The step of calculating cumulative damage of the repaired turbine blade in the operation of the liquid rocket engine based on the stress and strain data and estimating the cycle life of the repaired turbine blade comprises: calculating low-cycle fatigue damage and ratcheting damage of the repaired turbine blade based on the stress and strain data respectively; adding the low-cycle fatigue damage and the ratcheting damage to obtain the cumulative damage of the repaired turbine blade in the operation of the liquid rocket engine; determining the cycle life of the repaired turbine blade based on a time when the cumulative damage reaches a preset cumulative damage threshold.

8. A device for life prediction of a repaired turbine blade of a liquid rocket engine, characterized in that, The method comprises: a repairing module that obtains a target test piece for representing an un-repaired turbine blade of a liquid rocket engine and performs cladding repair on the target test piece; a test module that performs material performance test on the repaired target test piece to obtain a set of material performance parameters of the repaired turbine blade of the liquid rocket engine at different temperature points and under different strain amplitudes; a determination module that determines a constitutive model of the repaired turbine blade based on the set of material performance parameters and a hardening model combining Chaboche follow-up hardening and Voce nonlinear isotropic hardening through a particle swarm optimization algorithm, wherein the constitutive model is used to simulate stress and strain response of the repaired turbine blade under cyclic loading; a simulation module that simulates the working cycle of the repaired turbine blade based on the constitutive model to obtain stress and strain data of the repaired turbine blade at a dangerous point position; an estimation module that calculates cumulative damage of the repaired turbine blade in the operation of the liquid rocket engine based on the stress and strain data and estimates the cycle life of the repaired turbine blade.

9. An electronic device, comprising: The computer program stored in the readable storage medium is executed to implement the method of any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer program stored in the readable storage medium is executed to implement the method of any one of claims 1-7.

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