A dual-alloy turbine disc connection interface integrity evaluation and life prediction method and system

Abstract

The present application relates to the technical field of welded component quality evaluation, and particularly relates to a double-alloy turbine disc connecting interface integrity evaluation and life prediction method and system. The present application obtains interface equivalent material parameters through a welded sample rod test, divides the connecting interface into independent material domains in a finite element model, and gives the interface region temperature-related equivalent material properties. In combination with multi-field coupling calculation of rotating speed, temperature and aerodynamic load, the present application realizes evaluation of meridian plane and cylindrical surface rupture rotating speed, and performs low-cycle fatigue life prediction through a Manson-Coffin model. Test verification shows that the present application can accurately identify interface dangerous points and provide more reliable structure integrity and life prediction. The method provides a scientific basis for design finalization, test verification and engineering application of double-alloy turbine discs, and has high engineering feasibility.

Description

Technical Field

[0001] This invention relates to the field of welded component quality assessment technology, and in particular to a method and system for assessing the integrity of the connection interface and predicting the lifespan of a dual-alloy turbine disk. Background Technology

[0002] The improvement of thermal efficiency and thrust-to-weight ratio in aero-turbine engines has long relied primarily on increasing turbine inlet temperature and turbine rotor load-bearing capacity. As key load-bearing components subjected to the coupled effects of centrifugal, thermal, and aerodynamic loads, the strength, creep, and fatigue life of turbine disks / rotors directly determine the engine's safety margin and service reliability. With continuously rising turbine inlet temperatures and increasingly demanding service conditions for hot-end components, a single material system often struggles to simultaneously meet the requirements for creep resistance in high-temperature regions and low-cycle fatigue resistance in low-temperature regions. Therefore, the use of different materials in different temperature zones, leveraging their respective strengths and complementarity, has become a crucial development direction for turbine disk / bladed disk structures.

[0003] In existing high-temperature alloy systems, equiaxed cast nickel-based superalloys (such as K447A) typically possess good high-temperature creep performance and hot-end adaptability, making them suitable for use in high-temperature blades and local disk sections. Precipitation-hardening wrought nickel-based superalloys (such as GH4169) offer advantages in overall strength, toughness, and low-cycle fatigue performance in the mid-to-low temperature range, while also being more cost-effective and having a more mature supply chain. To balance these performance objectives, an engineering approach proposes using K447A for turbine blades and some disk sections near the high-temperature region, and GH4169 for the majority of the remaining disk sections, forming a dual-alloy turbine disk / dual-alloy turbine rotor structure through a joining process. This structure offers potential advantages in weight reduction, cost reduction, and improved reliability, while also avoiding the complex machining, fretting fatigue at the joint, and strength design difficulties associated with traditional GH4169 disk + K447A blade tenon and mortise connections.

[0004] In the joining process of dual-alloy turbine disks, solid-state joining technologies such as inertial friction welding are considered effective ways to achieve reliable joining of dissimilar high-temperature alloys due to their relatively controllable heat input, high joint quality, and good repeatability. Existing research (reference [Zhang Chuanchen, Zhang Tiancang, Zhao Chunling. Microstructure and high-temperature mechanical properties of K447A+GH4169 inertial friction welded joint [J]. Welding Journal, 2019, 40(10): 137-141. DOI: 10.12073 / j.hjxb.2019400275]) has carried out systematic experiments on inertial friction welded joints of dissimilar materials K447A and GH4169, reporting phenomena such as the formation of a fine recrystallization zone near the joint interface, the precipitated phase and dissolution behavior of the weld / heat-affected zone, and the diffusion transition zone of interfacial elements. The high-temperature mechanical properties of the joint after heat treatment were tested and analyzed, indicating that this type of dissimilar alloy friction welded joint can obtain high tensile strength and certain high-temperature creep performance. Another study (reference [Zhang Chuanchen, Zhao Chunling, Zhang Tiancang, Li Hui. Experimental study on inertial friction welding process of K447A+GH4169[J]. Materials Reports, 2018, 32(16):2783-2786.DOI:10.11896 / j.issn.1005-023X.2018.16.015]) further conducted experimental research on inertial friction welding of K447A+GH4169 from the perspective of process and performance, gave the joint microstructure evolution characteristics and mechanical property results, and reported the conclusions that the tensile strength of the joint can reach the same level as the K447A base material and the creep performance test time exceeds a certain threshold.

[0005] While the aforementioned literature provides important evidence for the engineering application of bialloy turbine disks from the perspectives of connection process feasibility and joint static strength / delay performance / microstructure characteristics, from the perspective of structural design and airworthiness verification, the key challenge for bialloy turbine disks is not only ensuring strong welds, but also assessing the structural integrity and lifespan of the connection interface under multi-field coupled loads. This is because the vicinity of the bialloy connection interface typically exhibits multiple coupled factors, including material composition / microstructure gradients, softening / strengthening in the heat-affected zone, residual stress, and stress concentration sensitivity. This results in the equivalent mechanical response in this region often not being entirely consistent with that of the two base materials. If the traditional assessment approach for single-material turbine disks is still used, it may lead to an overestimation or underestimation of the safety margin of the connection interface, thereby affecting design values ​​and experimental verification strategies.

[0006] From the perspective of existing engineering methods, the assessment of over-rotation fracture and low-cycle fatigue life of rotating disk structures has formed relatively mature and general theoretical and computational routes. Taking fracture speed assessment as an example, one of the classic empirical criteria is to correlate the average circumferential stress of the rotor at fracture with the tensile strength limit of the material (Robinson et al. method), and the average circumferential stress can be calculated through analytical derivation or finite element method, thereby predicting the fracture speed. Relevant technical literature (reference [NAFEMS. Calculation of the Hoop Burst Speed ​​for Rotating Discs (NBC08) [R / OL]) points out that this type of method essentially relies on the empirical correlation between the average circumferential stress and the material's tensile strength limit, and discusses the influence of factors such as finite element modeling, geometry, and yield criterion on the prediction results and conservatism.

[0007] In low-cycle fatigue life assessment, strain-life models (such as Manson-Coffin and its mean stress correction form) are commonly used in engineering to predict the life of critical components. Combined with the stress / strain cyclic response output from the finite element method, the life distribution is obtained, and the minimum value is used as the structural life control index. These methods are widely used in the strength verification and life design of single-material impellers / disks.

[0008] However, when the above-mentioned mature methods are directly applied to dual-alloy turbine disks, there are still obvious shortcomings: (1) Insufficient acquisition and characterization of interface material properties. Existing public research focuses on the microstructure and static / delay performance characterization of welded joints, but the wide-temperature-range elastoplastic parameters, fatigue parameters (SN, ε-N), and equivalent material models corresponding to the interface region required for structural design often lack systematic data support and parameterized expression. (2) The treatment of the interface region in finite element modeling is too idealized. In engineering analysis, the common practice is to assign material properties to K447A and GH4169 respectively, and then connect the meshes on both sides by means of common nodes / bonding / contact, etc., and the connection is assumed to be completely continuous without independent material domains. However, the actual connection interface often contains composite regions such as diffusion transition zone, recrystallization zone and heat-affected zone, and its mechanical properties cannot be simply represented by either side of the parent material or by linear interpolation. (3) The fracture speed and life assessment rules are mainly for homogeneous disks. As mentioned in reference [3], the correlation criteria between mean circumferential stress and strength limit are empirical and sensitive to finite element modeling details and geometry. When the structure exhibits significant material heterogeneity (such as independent response of the dual alloy interface), if the safety margin of the key interface location is directly inferred from the empirical rules of the homogeneous material disk, it is easy to amplify the uncertainty of the evaluation results. (4) Lack of an integrated process for integrity-life-test verification for dual alloy connection interfaces. In airworthiness review and engineering application scenarios, it is usually necessary to link material data, numerical models, evaluation indicators and test verification in a closed loop, and provide reproducible and traceable criteria and processes. However, existing public literature is more about the study of material joint performance or the theory / method of homogeneous disk rupture, and has not yet formed a standardized method for evaluation and life prediction of the connection interface of K447A / GH4169 dual alloy turbine disk.

[0009] In summary, while existing technologies have made progress in the microstructure and mechanical properties of K447A and GH4169 dissimilar material inertial friction welded joints, and have provided classical empirical criteria and finite element calculation focus points for predicting the fracture speed of rotating disks, a complete technical solution is still lacking for the critical weak link of the dual-alloy turbine disk connection interface. This solution can: obtain the equivalent material parameters of the interface over a wide temperature range; model the interface region as an independent material domain in the finite element model; and simultaneously complete the assessment of fracture speed and low-cycle fatigue life under multi-field load coupling conditions, all of which can be verified experimentally. Therefore, it is necessary to propose a systematic method for assessing the structural integrity and predicting the life of the dual-alloy turbine disk connection interface to improve the accuracy and engineering usability of the assessment, and provide a basis for the design finalization, experimental verification, and installation application of dual-alloy turbine disks. Summary of the Invention

[0010] The technical objective of this invention is to address the problems of heterogeneous material properties at the friction-welded interface of dual-alloy turbine disks composed of K447A and GH4169, the difficulty in accurately characterizing the interface mechanical response by assigning values ​​based on the base material in traditional finite element methods, and the lack of mature integrity and life assessment standards. This invention proposes an assessment method and system that obtains equivalent material parameters of the interface based on welded samples, divides the connection interface into independent interface regions in the finite element model and assigns values ​​separately, and completes the verification of the fracture speed and low-cycle fatigue life under coupled conditions of speed-temperature-aerodynamic load, which can be verified experimentally. This enables reliable prediction and engineering assessment of the structural integrity and life of the connection interface of dual-alloy turbine disks.

[0011] Firstly, in order to achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0012] A method for assessing the integrity of the interface and predicting the lifespan of a dual-alloy turbine disk, the method comprising the following steps:

[0013] S1. Establish the region containing turbine blades. Turbine disk area Interface area The finite element model of the turbine rotor, for Assigning material parameters to turbine blades ,right Assigning material parameters to the turbine disk and to The interface unit in the middle is assigned an equivalent material parameter function. ;

[0014] S2. Apply rotational load to the finite element model. Temperature loads or temperature boundaries are used to obtain the temperature field. And the aerodynamic load on the blades, to obtain the stress and strain fields of each part; S3, calculate the meridional fracture speed. Cylindrical surface fracture speed And take the predicted fracture speed ; and will With the qualified threshold The comparison is based on the completeness of the output. This represents the maximum rotational speed. S4. Based on the Manson-Coffin model corrected for mean stress, for... , and Solve the low-cycle fatigue life at the key locations respectively ;

[0015] S5. The output should at least include the connection interface area. The results of stress / strain peak values, fracture speed margin, and low-cycle fatigue life assessment.

[0016] Preferably, the method further includes step S0: preparing turbine blades and turbine disks, and within a temperature range Select multiple temperature points Mechanical and fatigue tests were conducted to obtain the set of equivalent material parameters for the interfaces of the turbine blades and turbine disk. ,in At least including the elastic modulus Poisson's ratio ultimate tensile strength , Specify non-proportional elongation strength and strain-life parameters , , , ,in, For temperature The fatigue strength coefficient below, For temperature The fatigue strength index below For temperature The fatigue ductility coefficient below For temperature The fatigue ductility index below; for the above Perform temperature fitting or interpolation to generate an interface equivalent material parameter function. In the presence of a temperature field At that time, according to the unit temperature Perform unit-by-unit updates;

[0017] And it connects to the interface with a dual alloy turbine disk design. Based on the reference, offset distances are set on both sides along the interface normal. Forming interface area Make the interface area thickness .

[0018] Preferably, the for ;

[0019] And / or, the temperature range in step S0 satisfies , ;

[0020] And / or, the test in step S0 further includes: symmetrical stress ratio High-cycle fatigue limit under certain conditions Experiments, and methods for fitting stress-life - fatigue test of curves, in which For stress amplitude, This represents the number of loop iterations.

[0021] And / or, the test in step S0 further includes a rupture stress-life test to obtain high-temperature rupture life parameters and incorporate them into the test. ;

[0022] Preferably, in step S1, the turbine rotor is modeled by extracting a cyclic symmetric segment and a cyclic symmetric constraint is applied to the cyclic symmetry plane.

[0023] And / or, the interface area in step S1 The grid size is less than or equal to the grid size of the adjacent turbine blade region and turbine disk region. This improves the resolution of stress / strain gradients at the interface.

[0024] Preferably, in step S3, the meridional fracture speed is calculated according to the following formula. Cylindrical surface fracture speed ,

[0025] ;

[0026] in, The strength limit of the part to be evaluated at its temperature. This represents the average circumferential stress at that location. This represents the maximum radial centrifugal stress at this location. Operating speed;

[0027] The qualified threshold mentioned in step S3 Pick ;

[0028] And / or, the fracture speed assessment in step S3 is performed on the turbine disk and the interface region respectively. and the output of the turbine blade section And give the margin respectively.

[0029] Preferably, in step S4, the following formula is used to... , and Solve the low-cycle fatigue life at the key locations respectively The minimum lifespan is taken as the low-cycle fatigue life of the turbine disk:

[0030] ;

[0031] in, For strain amplitude, The median of cyclic stress, The fatigue strength coefficient, The fatigue strength index. The fatigue ductility coefficient, It is the fatigue ductility index;

[0032] And / or, in step S4 , and Select at least one lifetime control point for each, and then take all lifetime control points. As a measure of the low-cycle fatigue life of the turbine disk.

[0033] Preferably, step S5 also includes verification through over-rotation fracture test and low-cycle fatigue test; the test verification includes: over-rotation fracture test of vertical high-speed wheel tester and low-cycle fatigue test of low-cycle fatigue tester, and error assessment of the test fracture speed and test life with the prediction results of steps S3 and S4 respectively.

[0034] Secondly, the present invention also provides a system for assessing the integrity and predicting the lifespan of a dual-alloy turbine disk connection interface, the system being used to implement the method, comprising:

[0035] The interface equivalent material parameter acquisition module is used to obtain the welding parameters of the turbine blade and turbine disk sample at a specific temperature point. The following experiments were conducted and the interface equivalent material parameter function was constructed. ;

[0036] The interface area division module is used to connect the interface. Based on the offset distance Build the interface area And determine ;

[0037] The finite element modeling and assignment module is used to create models containing... , and The finite element model, and Assign interface units;

[0038] The load and solver module is used to apply rotational loads. The system calculates temperature and aerodynamic loads and solves for the stress / strain field, outputting the results. , , and ;

[0039] The fracture speed assessment module is used to calculate according to step S3. , and and with threshold Compare;

[0040] The low-cycle fatigue life prediction module is used to solve the problem according to step S4. It also outputs the minimum lifetime value;

[0041] The results output and verification module is used to output interface integrity and life assessment results, and can optionally manage test verification data.

[0042] Thirdly, the present invention also provides a computer-readable storage medium having a computer program or instructions stored thereon, which, when executed by a processor, implement the steps of the method.

[0043] Fourthly, the present invention also provides a computer program product, including a computer program or instructions that, when executed by a processor, implement the steps of the method.

[0044] This invention, by employing the aforementioned technical solution, achieves a quantifiable and traceable assessment of the structural integrity and lifespan of the interface between dual-alloy turbine disks. Its technical advantages are mainly reflected in the following aspects: Firstly, addressing the objective fact that the mechanical properties of the friction-welded interface between K447A and GH4169 differ from both the K447A and GH4169 base materials due to the existence of diffusion transition zones, recrystallization zones, and heat-affected zones, this invention obtains parameters such as elasticity, strength, fatigue, and creep rupture from actual welded samples within a wide temperature range of 20℃ to 1050℃ and fits them as temperature-dependent interface equivalent materials. The model elevates interface material properties from empirical assumptions or simple interpolation to deterministic inputs driven by experimental data, fundamentally reducing the systematic bias of traditional co-node / bonded modeling of interface response. Furthermore, this invention divides the connection interface into interface regions of a certain thickness (e.g., 1 mm each) on both sides and introduces interface elements into the finite element mesh. This enables more realistic capture of stress / strain gradients, peak locations, and critical section migration phenomena near the interface under multi-field load coupling conditions, resulting in more stable extraction of lifetime control parameters such as equivalent stress, strain amplitude, and median cyclic stress at the connection location. This invention ensures reliability, significantly improving the accuracy and engineering consistency of fracture speed assessment and low-cycle fatigue life prediction. Furthermore, within the same computational framework, it performs meridional / cylindrical fracture speed checks on the GH4169 wheel disk region, interface region, and K447A blade disk region, providing a unified safety margin determination (e.g., ratio to maximum speed > 1.22). Based on the Manson-Coffin model with mean stress correction, it performs parallel calculations of the lifespan of the three regions and takes the minimum value as the overall low-cycle fatigue life of the entire disk, avoiding the omission of weak points caused by checking only a single region. This makes the evaluation results more consistent with the design logic of airworthiness and engineering safety. Furthermore, by verifying the predicted results through over-rotation fracture tests and low-cycle fatigue tests, a material-model-criteria-test closed loop can be formed. This not only improves the confidence of the prediction of the strength / life margin of the connection interface in the design stage, but also provides an executable evaluation process and data basis for the finalization, batch production consistency control and installation release of the dual alloy turbine disk. Ultimately, it achieves the comprehensive effect of reducing structural weight and manufacturing costs, reducing the risk of fretting fatigue of tenons and mortises, and improving the engineering application feasibility of dual alloy turbine disks while ensuring reliability. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of a dual-alloy turbine rotor.

[0046] Figure 2 Design of welding joint prototype

[0047] Figure 3 Schematic diagram of the initial geometric model and interface region for finite element analysis

[0048] Figure 4This is a schematic diagram of the dual alloy finite element model and interface elements.

[0049] Figure 5 This is a temperature field diagram.

[0050] Figure 6 This is a stress distribution diagram.

[0051] Figure 7 This is a strain distribution diagram.

[0052] Figure 8 This is a diagram showing the stress distribution at the connection point.

[0053] Figure 9 This is a strain distribution diagram at the connection point.

[0054] Figure 10 This is a flowchart illustrating the analysis process of the present invention. Detailed Implementation

[0055] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the implementation of the present invention is not limited to the following embodiments. Those skilled in the art can make equivalent substitutions or modifications to the methods for obtaining equivalent parameters of material grades, finite element solution software, load application methods, life model selection, etc., without departing from the concept and protection scope of the present invention, and all such substitutions or modifications should fall within the protection scope of the present invention.

[0056] For ease of description, this article will use K447A (equiaxed cast nickel-based superalloy) as the material for the high-temperature end blades and some disk sections, and GH4169 (precipitation hardening wrought nickel-based superalloy) as the main disk material. The evaluation will focus on the interface formed by friction welding (such as inertial friction welding / linear friction welding).

[0057] I. Explanation of Terms and Symbols

[0058] 1. Dual alloy turbine disk / dual alloy turbine rotor: refers to a turbine disk or bladed turbine rotor that is made of at least two different materials (e.g., K447A and GH4169) and formed into an integral load-bearing structure by welding.

[0059] 2. Connection Interface This refers to the geometric or engineering design interface formed between the K447A and GH4169 regions after welding. It should be noted that the actual welded joint often contains composite regions such as a diffusion transition zone, recrystallization zone, and heat-affected zone, and their mechanical properties are not entirely consistent with either base material.

[0060] 3. Interface Area : Connecting interface Centered on the interface, offset to both sides along the interface normal. The resulting finite-thickness region is used as an independent material domain in the finite element model. Its thickness is... .

[0061] 4. K447A area GH4169 area : These refer to the geometric domains belonging to materials K447A and GH4169 in the finite element model, respectively.

[0062] 5. Set of equivalent material parameters for the interface : The welding sample rod at temperature The set of equivalent material parameters for the interface region obtained through testing and fitting / interpolation includes at least: elastic modulus. Poisson's ratio ultimate tensile strength , Specify non-proportional elongation strength Fatigue strength coefficient Fatigue strength index Fatigue ductility coefficient Fatigue ductility index wait.

[0063] 6. Operating speed With the highest speed : This represents the actual operating speed of the turbine disk under the target operating conditions. This represents the highest possible rotational speed specified in the design under the operating conditions to be verified. The unit is usually r / min.

[0064] 7. Circumferential mean stress Maximum radial centrifugal stress These are the control stress indicators used to evaluate the fracture speed. Represents the average circumferential stress along the circumferential direction or a specified cross section; This represents the maximum radial centrifugal stress at a certain radius.

[0065] 8. Strain amplitude , median cyclic stress : Control variables in the low-cycle fatigue life model, where This represents the total strain amplitude. This is the median value of cyclic stress.

[0066] 9. Pass / Fail Threshold : Fracture speed margin threshold, when the ratio of the predicted fracture speed to the maximum speed meets the following condition. It is judged as qualified at that time; the best will be selected. (Can be adjusted according to airworthiness / company specifications).

[0067] II. System Structure of the Invention

[0068] This invention can also be implemented as a system for assessing the integrity and predicting the lifespan of the connection interface of a dual-alloy turbine disk, the structure of which can be divided into the following modules according to function:

[0069] Interface equivalent material parameter acquisition module: used to complete welding sample preparation, test plan generation, test data acquisition, data cleaning and parameter fitting, and output. This module can be connected to tensile testing machines, fatigue testing machines, high-temperature furnaces, extensometers, temperature control systems, etc., to achieve different temperature points. Material parameter testing was conducted.

[0070] Interface region segmentation module: used to read the 3D geometry or cross-sectional geometry of the dual-alloy turbine rotor and identify the connection interface. And based on the offset distance Automatically generate interface area .

[0071] Finite element modeling and material assignment module: used to create finite element modeling and material assignment modules. , , Finite element model; for Assigning material parameters to K447A ,right Assigning material parameters to GH4169 ,right Assigning interface equivalent material parameters Supports cyclic symmetric modeling and interface unit encrypted mesh.

[0072] Load and Solver Module: Used to apply rotational loads (centrifugal force), temperature loads, or thermal boundaries (to obtain the temperature field). The system calculates the stress and strain fields for blade aerodynamic loads and outputs the key sections / key points. , , , wait.

[0073] The fracture speed evaluation module is used to determine the fracture speed based on the stress parameters and ultimate tensile strength obtained from the solution. Calculate the fracture speed margin and provide a pass / fail determination.

[0074] Low-cycle fatigue life prediction module: used for Manson–Coffin model corrected based on mean stress. , , The lifespan is predicted for three parts and the minimum value is taken. The lifespan control part and lifespan value are output.

[0075] Results Output and Verification Module: Used to generate evaluation reports, including the peak location of interface stress / strain, fracture speed margin, low-cycle fatigue life, and comparative verification conclusions with experimental results; it can manage over-rotation fracture test and low-cycle fatigue test data to achieve closed-loop verification.

[0076] The above system can be deployed on an engineering workstation or server. Solving can be done using commercial finite element software (such as ANSYS, ABAQUS, etc.) or a self-developed solver; parameter fitting can be achieved using numerical calculation software; and parameter files, mesh files, load case files, and result files are transferred between modules via data interfaces. Those skilled in the art can directly implement this system based on the above module division.

[0077] III. Specific Technical Route for Implementing the Method of the Invention

[0078] like Figure 10 As shown, the overall process of this invention can be summarized as follows: (1) manufacture welding sample bars and determine the equivalent material mechanical properties of the bi-alloy connection interface; (2) divide the interface region (e.g., 1 mm each) from the connection interface as the center to both sides; (3) establish a finite element model containing interface elements and perform mesh generation; (4) apply rotational speed, temperature and aerodynamic load and solve for stress / strain; (5) evaluate the fracture speed of each part; (6) evaluate the low-cycle fatigue life of each part and take the minimum value; (7) verify through over-rotation fracture test and low-cycle fatigue test, and put it into installation and application after passing the test.

[0079] IV. Detailed Implementation of Key Steps

[0080] (a) Step S1: Obtaining the equivalent material parameters of the interface

[0081] 1. Design and fabrication of welding prototypes

[0082] like Figure 2 As shown, to ensure the representativeness of the interface equivalent material parameters, the welding process window of the welded prototype should be as consistent as possible with or equivalent to the actual process of the dual-alloy turbine disk. The welded prototype can be prepared using K447A and GH4169 raw materials from the same batch or with the same composition and specifications as the engineering part. The prototype structure typically includes:

[0083] GH4169 section: serving as one end of the parent material segment;

[0084] K447A section: serving as the other end of the parent material section;

[0085] Welding area: located at the joint between the two sections;

[0086] Clamping position: Used for clamping in friction welding equipment to ensure coaxiality and stable load transfer during the welding process.

[0087] The preparation process may include:

[0088] (a) Raw material blanking and rough machining: K447A bar stock / casting and GH4169 bar stock / forging are machined to the specified diameter and length, and the end face is machined to ensure flatness and perpendicularity;

[0089] (b) Surface cleaning: Degrease, remove oxide scale and clean the weld end face to reduce the risk of inclusions and incomplete welding;

[0090] (c) Friction welding connection: Inertial friction welding or linear friction welding is used to form a solid-phase joint under the set process window of friction pressure, upsetting pressure, friction time / inertia, rotation speed, etc.

[0091] (d) Post-weld heat treatment (optional but recommended): Perform post-weld heat treatment according to the specification heat treatment regime of K447A and GH4169 or the engineering part regime to make the joint structure similar to the engineering part and reduce the interference of residual stress difference on parameter extraction.

[0092] 2. Test temperature points and test item planning

[0093] To achieve a wide temperature range (e.g.) Interface equivalent material parameter function Multiple temperature points can be selected. (Conduct tests at several points, such as room temperature, medium temperature, and high temperature.) At each temperature point, at least the following items should be performed:

[0094] (1) Elastic parameter: elastic modulus Poisson's ratio ;

[0095] (2) Static strength parameter: ultimate tensile strength Specified non-proportional elongation strength ;

[0096] (3) Fatigue parameters:

[0097] High-cycle fatigue (optional): Achieve fatigue limit or - curve( For stress amplitude, (number of loops);

[0098] Low-cycle fatigue (recommended): To achieve strain-life ( - ) data, and fit to obtain , , , ;

[0099] (4) Creep / Persistence Parameters (Optional): Obtain the creep stress-life curve to support long-term service evaluation in the high-temperature range.

[0100] Among them, low-cycle fatigue parameters are the key inputs for life prediction in this invention, and it is recommended to cover the main temperature points in the actual service temperature range.

[0101] 3. Implementation logic for equivalence between sample sampling location and interface

[0102] Traditional material testing typically targets homogeneous base materials, while this invention aims to address the interfacial region. The mechanical properties of the substrate are inconsistent with those of the base materials on both sides, and the parameters of the base materials K447A or GH4169 cannot be simply used as substitutes. Therefore, this invention adopts the following interface equivalence logic:

[0103] Sampling principle: The gauge length (or critical stress section) of all mechanical specimens should cover the area near the interface of the weld joint so that the test response can comprehensively reflect the overall equivalent behavior of the composite areas such as the diffusion transition zone, recrystallization zone and heat-affected zone.

[0104] Equivalent objective: To obtain a set of parameters that can be used in finite element interface elements to equivalently describe the elastic-strength-fatigue response of the interface region at a given temperature. .

[0105] Engineering reproducibility: Through standardized sample bar structure, sampling methods, and fitting techniques, comparable samples can be obtained from different batches. This facilitates batch production consistency assessment.

[0106] In practice, one or a combination of the following methods can be used:

[0107] Method A (Recommended, Direct Equivalent): Arrange the center of the gauge length of the tensile / fatigue specimen near the weld center or interface, so that fracture / fatigue cracks are more likely to occur near the interface influence zone, thus the test data naturally characterize the equivalent properties of the interface.

[0108] Method B (Partition Equivalence): Define the interface region as having a certain thickness (e.g., 1mm offset on each side) centered on the interface. Perform microhardness / structure partitioning on this region and combine tensile and fatigue fracture location statistics to map the test results to the equivalent parameters of this interface region.

[0109] Method C (Inversion Assistance, Enhanced Robustness): If the interface region is very thin and the experimental fracture is unstable, a local indentation-finite element inversion method can be introduced to assist in calibrating the interface elastic / yield parameters, making... and To more closely approximate the actual response of the interface micro-area, fatigue parameters are then fitted using overall fatigue testing.

[0110] The above approach does not change the core idea of ​​this invention: the interface equivalent parameters are derived from the experimental data of real welded joints, rather than base material assumptions or simple interpolation.

[0111] 4. Data processing, fitting, and parameter function construction

[0112] (1) Data cleaning and consistency check: For each temperature point Outlier identification was performed on multiple sets of experimental data to check temperature stability, strain measurement effectiveness, and whether the fracture location met the requirements for covering the interface influence zone. If the fracture significantly deviated from the interface region, the data set could be used as a base material reference and not included in the interface equivalence fitting.

[0113] (2) Determination of elasticity and strength parameters: It can be obtained from the slope of the elastic segment of the tensile curve or from dynamic elasticity testing; It can be obtained by transverse / longitudinal strain measurement; The maximum engineering stress is the maximum stress on the tensile curve. according to Determined by offset method.

[0114] (3) Low-cycle fatigue parameter fitting: The life data under different strain amplitudes are fitted to obtain fatigue parameters. , , , The goal of fitting is to make subsequent lifetime prediction models directly usable.

[0115] (4) Temperature correlation function Construction: When temperature points are a discrete set When this is the case, piecewise linear interpolation, spline interpolation, or polynomial fitting can be used to form a continuous function. To ensure engineering reproducibility, piecewise linear interpolation is preferred: in and Arbitrary temperature can be obtained by linear interpolation between them. The parameter value.

[0116] For example, for The interpolation can be expressed as:

[0117] ;

[0118] in, For temperature The equivalent elastic modulus of the interface below; , These are adjacent test temperature points; , The elastic modulus is determined by tests at the corresponding temperature points.

[0119] This completes the interface equivalent material parameter function. The construction of this provides input for the subsequent assignment of values ​​to the finite element interface elements.

[0120] (II) Step S2: Interface area division

[0121] like Figure 3 As shown, the present invention extends the connection interface from a geometrically zero-thickness surface to an interface region with a finite thickness. This addresses the problem that traditional common node / bonding models cannot reflect the true material response in the interface transition zone.

[0122] 1. Interface recognition

[0123] In the 3D model or meridional section model of the dual alloy turbine disk, the connection interface Typically, the design mating surfaces / welding positions corresponding to K447A and GH4169 (see...) Figure 1 (Annotated connection interface). Interface recognition can be achieved in the following ways:

[0124] If the CAD model explicitly specifies split modeling: directly read the assembly contact surface of the two material parts as... ;

[0125] For a single solid object: the welding position can be determined and a split surface generated using geometric features (such as diameter steps, transition fillet center surfaces) or process records. .

[0126] 2. Offset generation interface area

[0127] by Based on the reference, offset distances are set on both sides along the interface normal. Two bias planes are formed and The volume between the two bias planes is the interface region. The thickness of the interface area is: ;in, The thickness of the interface area; This is the one-sided offset distance.

[0128] In a preferred embodiment, Pick That is, the interface is divided to both sides. This is an interface area, but the invention is not limited thereto. The dimensions can be determined based on the width of the weld influence zone, the mesh size, and the structural dimensions. This ensures that the interface units can cover the main organizational transition area without being overly expanded, which would cause distortion of the interface's equivalent parameters.

[0129] 3. Engineering significance of the interface area

[0130] By building This invention makes the material heterogeneity near the interface explicit at the finite element level, thereby enabling:

[0131] 1) Provide sufficient resolution where stress / strain gradients are steep to prevent stress peaks from being flattened by mesh or binding constraints;

[0132] 2) Allows the interface region to use independent temperature-dependent material parameters. It truly reflects the equivalent response of the interface composite structure;

[0133] 3) Supports the subsequent extraction of life control quantities and safety margins for individual interface areas, forming an auditable and traceable assessment conclusion.

[0134] (III) Step S3: Finite element modeling and material assignment

[0135] like Figure 4 As shown, the present invention clearly divides the K447A blade element, GH4169 disk element and interface element in the finite element model, and assigns material properties to each of them.

[0136] 1. Modeling object and cyclic symmetric segmentation

[0137] Turbine rotors typically have a periodic blade distribution. To improve computational efficiency, a cyclically symmetrical segment can be selected for analysis.

[0138] The method is as follows: with the rotor's rotation axis as the center, determine the symmetry angle according to the number of blades or the number of structural cycles. The geometry within this angular range is selected as the solution domain, and cyclic symmetry constraints are applied to the cyclic symmetry planes on both sides (see...). Figure 4 The engineering significance of cyclic symmetry constraints lies in ensuring that the displacement and load transfer of the circumferential segment satisfy periodicity, thereby approximating the overall response with a smaller model. As a cyclically symmetrical angle, it can be derived from Divide by the number of cycles to obtain; the number of cycles is usually equal to the number of blades or the number of repeating sectors.

[0139] 2. Grid generation and interface unit encryption

[0140] Mesh generation follows these principles:

[0141] 1) The regional mesh should be appropriately refined, and the size of the interface unit should preferably not exceed the size of the adjacent parent material regional unit. To capture interface gradients;

[0142] 2) Densify the density in stress concentration areas such as geometric transition fillets, steps, and blade root transitions;

[0143] 3) Use structured / semi-structured meshes to improve the stability of the solution. If necessary, use compatible meshes or transition elements at the interface transition to reduce numerical errors.

[0144] Figure 4 The diagram illustrates three types of element regions: K447A blade elements, GH4169 disk elements, and interface elements. Interface elements maintain continuity with adjacent parent material elements at nodes (sharing nodes), but their material properties differ, thus achieving realistic modeling of geometric continuity and material heterogeneity.

[0145] 3. Material property assignment and temperature-related updates

[0146] right Temperature-dependent material parameters assigned to K447A ;

[0147] right Temperature-dependent material parameters assigned to GH4169 ;

[0148] right Assign the interface equivalent material parameters obtained in step S1. .

[0149] In the presence of a temperature field In the case of (see) Figure 5 The present invention preferably employs a unit-by-unit temperature mapping method: first, thermal analysis or steady-state temperature field solution is performed to obtain the temperature of each unit or node. Then call the corresponding material parameters (e.g., according to the interpolation function) , , This method (e.g., [missing information]) allows for the updating of interface material properties as temperature changes. This results in different stiffness / strength / fatigue parameters at high and low temperatures in the interface region, thus better reflecting real-world working conditions. Among these, For position Temperature; It is a spatial coordinate vector.

[0150] 4. Boundary conditions and contact / connection processing

[0151] Since this invention treats the interface region as a solid material domain, there is typically no need to set up binding or contact at the interface; the interface region and the base material region can be connected using shared nodes or compatible meshes. For integrated blade and disk structures (see...), Figure 1 If the blade and disk segment are integrally cast / welded, they can also be modeled as an integral solid; if it is an assembly structure, then corresponding contact relationships need to be set at the assembly contact points, but this does not affect the interface area modeling concept of this invention.

[0152] (iv) Step S4: Applying multi-field loads and solving stress / strain

[0153] After modeling, apply typical operating loads to the turbine rotor and solve for the loads. The loads include at least:

[0154] Speed ​​load (centrifugal force): The operating speed Convert to angular velocity This force is applied to the model to generate centrifugal force. The relationship between angular velocity and rotational speed is:

[0155] ;

[0156] in, Angular velocity (unit: rad / s); Rotational speed (in r / min); Pi is the mathematical constant of a circle.

[0157] Temperature load: The temperature field can be obtained using steady-state thermal analysis (see...). Figure 5 Then, in the structural analysis, the temperature field is used as the load input, and the thermal strain and temperature-dependent material properties are considered. The temperature boundary can be given by the heat transfer conditions of the engine's hot end airflow, cooling conditions, or experimental temperature measurement data.

[0158] Aerodynamic load: The aerodynamic pressure distribution load on the blade surface can be given by aerodynamic calculations, experimental data, or empirical distribution, and is equivalent to the blade surface pressure / concentrated force. This load, together with the rotational speed and temperature, determines the stress level at the blade root and near the interface.

[0159] The solution output includes: equivalent stress contour map and equivalent strain contour map, with a focus on extracting the interface region. The location and values ​​of nearby stress / strain peaks are used for subsequent rupture and life assessment.

[0160] (V) Step S5: Rupture speed assessment

[0161] This invention, within the same model framework, evaluates the fracture speed of the GH4169 wheel disk, the interface region, and the K447A blade disk, and outputs a unified margin judgment. Fracture modes can include two categories: meridional fracture and cylindrical fracture.

[0162] 1. Meridional fracture speed When the circumferential average stress of the disk reaches the uniaxial tensile strength limit of the material, the disk may fracture along the meridional section. The corresponding fracture speed is calculated as follows:

[0163] ;

[0164] in, This refers to the fracture speed at the meridional plane. Operating speed; The strength limit of this part at the corresponding temperature (e.g.) , , ); This represents the average circumferential stress at that location.

[0165] 2. Cylindrical surface fracture speed

[0166] When the radial average stress at any radius of the disk reaches the material's uniaxial tensile strength limit, the disk may fracture along the cylindrical surface. The corresponding fracture speed is calculated as follows:

[0167] ;

[0168] in, The fracture speed of the cylindrical surface; This represents the maximum radial centrifugal stress.

[0169] 3. Predicted fracture speed and qualification criteria

[0170] The smaller of the two fracture speeds is taken as the predicted fracture speed:

[0171] ;

[0172] in, To predict the fracture speed.

[0173] The qualification criteria are:

[0174] ;

[0175] in, This is the maximum speed; The preferred threshold is the one that meets the qualification requirements. .

[0176] In the above calculations and The extraction can be achieved according to engineering specifications, such as averaging stress along the thickness or radius direction on the meridional section; for The radial stress peak value can be searched at each radius and the maximum value is taken. This invention does not limit the specific numerical algorithm, but emphasizes that the same extraction rule should be used consistently in all three parts to ensure comparability between the parts.

[0177] (vi) Step S6: Low-cycle fatigue life analysis

[0178] This invention employs the Manson-Coffin method with mean stress correction for low-cycle fatigue life prediction. Its basic equation is:

[0179] ;

[0180] in: This represents the total strain amplitude; This is the fatigue strength coefficient; This is the median value of cyclic stress; It is the elastic modulus; Fatigue life (number of cycles); The fatigue strength index; It is the fatigue ductility coefficient; This is the fatigue ductility index. Of the parameters mentioned above, , , , , All are temperature-related parameters, taken from... , , Or obtained from its interpolation; and Extracted from finite element calculation results.

[0181] During implementation, it is possible , , Each selects at least one life control point (preferably the peak point of the equivalent strain amplitude or the stress concentration point) and solves for the life respectively. The minimum value among the three is taken as the low-cycle fatigue life of the turbine disk.

[0182] ;

[0183] in, , , The low-cycle fatigue life of the GH4169 rotor disk, interface, and K447A blade disk are respectively. To control the lifespan of the entire system.

[0184] like Figures 6 to 9 As shown, the stress / strain distribution characteristics of the entire disk and the connection points can be observed. In engineering, a high gradient region often exists near the interface. Therefore, this invention uses interface elements and equivalent interface parameters to make the lifetime prediction of this region more reliable, avoiding mistaking the interface for the base material and causing lifetime deviations.

[0185] (vii) Step S7: Experimental verification

[0186] To establish a closed-loop verification process encompassing materials, models, criteria, and experiments, this invention proposes the following experiments:

[0187] Overspeed fracture test: A physical bi-alloy turbine disk is manufactured and subjected to an acceleration test on a vertical high-speed turbine disk tester until the specified overspeed or fracture conditions are reached, and the measured fracture speed is obtained. Compare it with the predicted value. In comparison, the assessment error is consistent with the margin.

[0188] Low-cycle fatigue testing: Low-cycle fatigue tests are performed on blade disks or key structural sections on a low-cycle fatigue testing machine to obtain the measured life. and with predicted lifespan Comparative verification.

[0189] Acceptance criteria and installation release: When the fracture speed margin meets the criteria and the life prediction and test consistency meet the engineering specifications, the acceptance and evaluation process is effective and can be used for design finalization and batch production consistency control in actual installation applications.

[0190] V. Application Examples:

[0191] (a) Welding sample bar test library construction to obtain equivalent material parameters of the joint interface and use them for simulation input.

[0192] (1) Setting the consistency between the sample and the process

[0193] like Figure 2 As shown, a sample bar for the welded joint is fabricated using GH4169 and K447A bars. One end is GH4169, the other end is K447A, and the middle is the welding area. Clamping positions are provided at the ends to meet the clamping and coaxial loading requirements of the friction welding equipment. The welding process (friction pressure, upsetting pressure, friction time / inertia, rotational speed, etc.) is set according to the process window of the bimetallic turbine disk engineering component. Post-weld heat treatment is performed according to the engineering specifications (optional, but preferred) to ensure that the joint microstructure and residual stress state are representative.

[0194] (2) Wide temperature range mechanical property test plan

[0195] Within temperature range Select several temperature points inside The following experiments were conducted, and the experimental data were incorporated into the interface equivalent material database:

[0196] Elastic parameter: elastic modulus Poisson's ratio ;

[0197] Static strength: ultimate tensile strength , Specify non-proportional elongation strength ;

[0198] Fatigue performance: - Curve (high-cycle fatigue) and - Curve (low-cycle fatigue), and fit fatigue parameters , , , ;

[0199] - (Optional) Duration / Creep: Duration stress-life curve for extended high-temperature durability life assessment.

[0200] (3) Methods for obtaining interface equivalent parameters

[0201] Unlike traditional methods that directly take parameters from the K447A or GH4169 base material, this example involves sampling and arranging the specimen along the gauge length / critical section to cover the weld-affected zone (including the diffusion transition zone, recrystallization zone, and heat-affected zone) to ensure accurate measurements. , , - Parameters and other information reflect the connection interface area. The equivalent response is thus formed, thereby creating a set of equivalent material parameters for the interface. This set is directly called by subsequent finite element interface elements to achieve data-driven assignment of interface materials.

[0202] (4) Demonstration of technical effects

[0203] Through experimentation and data processing, the variation with temperature can be stably obtained. Furthermore, it was observed that the elastic / strength / fatigue parameters of the interface region typically exhibit characteristics different from those of the parent material on either side (e.g., the modulus, yield, and fatigue parameters in some temperature ranges are not equivalent to those of the GH4169 or K447A parent material). This study fundamentally solves the key problem of accurately selecting interface material properties in existing analyses, providing a reliable input basis for subsequent structural integrity assessments.

[0204] (II) Integrity assessment and life prediction of the connection interface of the dual alloy turbine disk

[0205] This example uses Figure 1 Using the dual-alloy turbine rotor shown as the object, the interface region modeling, multi-field coupling calculation, fracture speed evaluation and low-cycle fatigue life prediction are completed according to the process of this invention, and finite element output and interface hazard quantity extraction results that can directly reflect the technical effect are given.

[0206] (1) Interface area division and modeling

[0207] Identify connection interfaces in CAD geometry or meridional section models. ( Figure 1 (Location of the connection interface on the right). For example... Figure 3 As shown, with Divide into two sides from the center. Forming an interface area Its thickness is

[0208] ;

[0209] in, The thickness of the interface area. The offset distance of the interface to one side.

[0210] This process transforms the interface from a zero-thickness bonded surface into a solid region that can be assigned independent material parameters, facilitating the capture of stress / strain gradients and the migration of critical points.

[0211] (2) Finite element mesh and material assignment

[0212] like Figure 4 As shown, a cyclically symmetric segment is selected for finite element modeling, and cyclic symmetry constraints are applied to the cyclic symmetry plane; K447A blade and high-temperature disk area. Assigning temperature-dependent material parameters to K447A GH4169 Roulette Area Assigning material parameters to GH4169 Interface area Assigning the equivalent parameters of the interface obtained from application example 1 Local encryption of interface units is implemented to improve the accuracy of interface hazard extraction.

[0213] (3) Application of multiple loads and temperature field input

[0214] Rotational speed load (centrifugal force), temperature load, and blade aerodynamic load are applied to the model. The temperature field is input using steady-state thermal analysis results. Figure 5 Its temperature scale is clearly given: the highest temperature is approximately The lowest temperature is approximately This indicates a significant temperature gradient between the blade tip / high-temperature section and the disk's low-temperature section. This temperature field serves two purposes:

[0215] 1) It generates thermal strain and thermal stress;

[0216] 2) Driver , , Temperature-related updates enable interface units to call corresponding material parameters based on local temperature at different locations.

[0217] (4) Stress / strain distribution and extraction of interface hazard quantities

[0218] After completing the solution, the stress distribution of the entire disk is obtained. Figure 6 ) and local stress distribution at the connection location ( Figure 8 ), and the corresponding strain distribution ( Figure 7 , Figure 9 Representative results can be directly read from the ruler in the attached chart:

[0219] Whole-board equivalent stress distribution ( Figure 6 The maximum equivalent stress is approximately (The maximum value of the scale shown in the figure) indicates that there is a significant stress concentration area in the structure;

[0220] Equivalent stress distribution at connection location ( Figure 8 The maximum local equivalent stress at the interface is approximately (The maximum value of the scale is shown in the figure), and a local danger point is formed at the Max mark in the figure;

[0221] Equivalent variation distribution of connection location ( Figure 9 The local maximum equivalent strain of the interface is approximately The minimum is approximately (Read from the scale in the figure) This indicates that there is a considerable strain level and gradient in the interface region under service load.

[0222] The above results directly prove that: by setting the interface area and assigning... The calculation results can explicitly present the dangerous response (stress / strain peak and gradient) of the interface, providing extractable and traceable control quantities for subsequent fracture speed and low-cycle fatigue life assessment.

[0223] Key technical effects: If not established Furthermore, by using only common nodes / bonding and directly applying the properties of the parent material, the stress / strain gradient in the interface region is often averaged / weakened, which can easily lead to an underestimation of the critical quantity at the interface or a shift in the location of the critical point; while the model of this invention can... Figure 8 , Figure 9 The system clearly identifies dangerous points on the interface (at the Max point), thereby improving the relevance and reliability of the assessment.

[0224] (5) Rupture speed evaluation

[0225] After obtaining the stress field, respectively... (GH4169 Roulette) (Interface area) and The fracture speed of the K447A blade disk section was checked using two criteria: meridional fracture and cylindrical fracture (consistent with the technical specifications). The smaller of the two criteria was used as the predicted fracture speed. And then with the highest speed Determine if the ratio is acceptable:

[0226] ;

[0227] in, The fracture speed at the meridional plane. The fracture speed of the cylindrical surface. Maximum rotational speed. Strength limit. Temperature-related (in) Preferred selection This avoids the margin deviation caused by mistaking the interface material for GH4169 or K447A.

[0228] (6) Low-cycle fatigue life prediction

[0229] In the lifetime assessment of the interface, the Manson–Coffin equation with mean stress correction is used:

[0230] ;

[0231] in, This represents the total strain amplitude. The fatigue strength coefficient, The median of cyclic stress, The fatigue strength index. The fatigue ductility coefficient, The fatigue ductility index, For elastic modulus, Fatigue life (number of cycles).

[0232] In this example, the extraction of the interface lifetime control quantity is directly based on... Figure 9 The strain level at the connection location shown (e.g., the maximum equivalent strain is approximately) ), and combined At the corresponding temperature , , , , Wait, to obtain the interface lifetime. Similarly, we can obtain and The minimum value among the three is taken as the overall low-cycle fatigue life control value:

[0233] ;

[0234] This invention not only calculates the lifespan, but also outputs the interface as an independent evaluation object. Furthermore, within a unified framework of three parts, the control life and control location are given, thus addressing the practical gap that the interface life of dual alloy turbine disks cannot be assessed independently.

[0235] (III) Experimental verification of closed loop – verification and evaluation conclusions of over-rotation fracture test and low-cycle fatigue test

[0236] To demonstrate the engineering applicability of the evaluation process of this invention, this example conducts experimental verification of the evaluation results obtained in (II) and compares and verifies the correctness of the identification of interface hazard points and the judgment of life control parts.

[0237] (1) Over-rotation fracture test (vertical high-speed wheel disc tester)

[0238] Manufacturing and Figure 1 Consistent dual-alloy turbine disk / rotor prototypes were subjected to over-revving tests on a vertical high-speed disk tester according to the specified acceleration curve:

[0239] Test monitoring: Rotational speed Vibration, strain (optional patch / telemetry), temperature (optional), and acoustic emission (optional);

[0240] Judgment method: when reached Maintain the speed at each stage and check for any abnormalities; if the speed continues to increase until rupture, record the rupture speed and rupture location.

[0241] Validation results are expressed as follows:

[0242] 1) Tests show that the sample meets the integrity requirements during the specified over-spin margin stage (corresponding to this invention). (Engineering verification of the criterion)

[0243] 2) Macroscopic observation and metallographic / fracture analysis of the fracture / initiation location show a high-response area near the interface between the danger zone and the finite element prediction. Figure 8 Near Max Figure 9 The high-strain region exhibits consistency, thus demonstrating the invention's ability to identify interface hazards.

[0244] (2) Low-cycle fatigue test (low-cycle fatigue testing machine)

[0245] Low-cycle fatigue tests can be conducted on key components of the blade disk using both temperature and strain control methods.

[0246] Loading method: strain amplitude control, cycle ratio and frequency are set according to specifications;

[0247] Monitoring content: Cyclic stress response, hysteresis loop evolution, crack initiation / propagation (can be checked using DIC / acoustic emission / shutdown inspection);

[0248] Termination condition: Failure criteria are met (crack size, stiffness reduction, or fracture).

[0249] Validation results are expressed as follows:

[0250] 1) The lifetime level obtained from the experiment and the control lifetime output by the model of this invention Consistent within the allowable deviation range of the project;

[0251] 2) Lifespan control components preferentially appear at or near the connection interface, consistent with the present invention. Independently assessed This aligns with the conclusion that the value is minimized, thus proving that treating the interface region as an independent material domain and assigning values... This can significantly improve the relevance and reliability of lifespan prediction.

[0252] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

[0253] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0254] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0255] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0256] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0257] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0258] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, like read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0259] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

Claims

1. A method for assessing the integrity of the connection interface and predicting the lifespan of a dual-alloy turbine disk, characterized in that, The method includes the following steps: S1. Establish the region containing turbine blades. Turbine disk area Interface area The finite element model of the turbine rotor, for Assigning material parameters to turbine blades ,right Assigning material parameters to the turbine disk and to The interface unit in the middle is assigned an equivalent material parameter function. ; S2. Apply rotational load to the finite element model. Temperature loads or temperature boundaries are used to obtain the temperature field. And the aerodynamic load on the blades, and the stress field and strain field of each part are obtained by solving; S3, Calculate the meridional fracture speed Cylindrical surface fracture speed And take the predicted fracture speed ; and will With the qualified threshold The comparison is based on the completeness of the output. This is the maximum speed; S4. Based on the Manson-Coffin model with mean stress correction, for , and Solve the low-cycle fatigue life at the key locations respectively ; S5. The output should at least include the connection interface area. The results of stress / strain peak values, fracture speed margin, and low-cycle fatigue life assessment; The method also includes step S0: fabricating turbine blades and turbine disks, and within a temperature range Select multiple temperature points Mechanical and fatigue tests were conducted to obtain the set of equivalent material parameters for the interfaces of the turbine blades and turbine disk. Regarding the above Perform temperature fitting or interpolation to generate an interface equivalent material parameter function. .

2. The method according to claim 1, characterized in that, In step S0 At least including the elastic modulus Poisson's ratio ultimate tensile strength , Specify non-proportional elongation strength and strain-life parameters , , , ,in, For temperature The fatigue strength coefficient below, For temperature The fatigue strength index below For temperature The fatigue ductility coefficient below For temperature Fatigue ductility index under the following conditions; in the presence of a temperature field At that time, according to the unit temperature Perform unit-by-unit updates; And it connects to the interface with a dual alloy turbine disk design. Based on the reference, offset distances are set on both sides along the interface normal. Forming interface area Make the interface area thickness .

3. The method according to claim 2, characterized in that, The for ; And / or, the temperature range in step S0 satisfies , ; And / or, the test in step S0 further includes: symmetrical stress ratio High-cycle fatigue limit under certain conditions Experiments, and methods for fitting stress-life - fatigue test of curves, in which For stress amplitude, This represents the number of loop iterations. And / or, the test in step S0 further includes a rupture stress-life test to obtain high-temperature rupture life parameters and incorporate them into the test. .

4. The method according to claim 1, characterized in that, In step S1, the cyclic symmetric segment of the turbine rotor is modeled, and cyclic symmetric constraints are applied to the cyclic symmetry plane. And / or, the interface area in step S1 The grid size is less than or equal to the grid size of the adjacent turbine blade region and turbine disk region. This improves the resolution of stress / strain gradients at the interface.

5. The method according to claim 1, characterized in that, In step S3, the meridional fracture speed is calculated according to the following formula. Cylindrical surface fracture speed , ； in, The strength limit of the part to be evaluated at its temperature. This represents the average circumferential stress at that location. This represents the maximum radial centrifugal stress at this location. Operating speed; The qualified threshold mentioned in step S3 Pick ; And / or, the fracture speed assessment in step S3 is performed on the turbine disk and the interface region respectively. and the output of the turbine blade section And give the margin respectively.

6. The method according to claim 1, characterized in that, In step S4, the following formula is used to... , and Solve the low-cycle fatigue life at the key locations respectively The minimum lifespan is taken as the low-cycle fatigue life of the turbine disk: ； in, For strain amplitude, The median of cyclic stress, The fatigue strength coefficient, The fatigue strength index, The fatigue ductility coefficient, It is the fatigue ductility index; And / or, in step S4 , and Select at least one lifetime control point for each, and then take all lifetime control points. As a measure of the low-cycle fatigue life of the turbine disk.

7. The method according to claim 1, characterized in that, Step S5 also includes verification through over-rotation fracture test and low-cycle fatigue test; the test verification includes: over-rotation fracture test of vertical high-speed wheel tester and low-cycle fatigue test of low-cycle fatigue tester, and error assessment of the test fracture speed and test life with the prediction results of steps S3 and S4 respectively.

8. A system for assessing the integrity of the connection interface and predicting the lifespan of a dual-alloy turbine disk, characterized in that, The system is used to implement the method according to any one of claims 1-7, comprising: The interface equivalent material parameter acquisition module is used to obtain the welding parameters of the turbine blade and turbine disk sample at a specific temperature point. The following experiments were conducted and the interface equivalent material parameter function was constructed. ; The interface area division module is used to connect the interface. Based on the offset distance Build the interface area And determine ; The finite element modeling and assignment module is used to create models containing... , and The finite element model, and Assign interface units; The load and solver module is used to apply rotational loads. The system calculates temperature and aerodynamic loads and solves for the stress / strain field, outputting the results. , , and ; The fracture speed assessment module is used to calculate according to step S3. , and and with threshold Compare; The low-cycle fatigue life prediction module is used to solve the problem according to step S4. It also outputs the minimum lifetime value; The results output and verification module is used to output interface integrity and life assessment results, and can optionally manage test verification data.

9. A computer-readable storage medium having a computer program or instructions stored thereon, characterized in that, When the computer program or instructions are executed by a processor, they implement the steps of the method according to any one of claims 1-6.

10. A computer program product, comprising a computer program or instructions, characterized in that, When the computer program or instructions are executed by a processor, they implement the steps of the method according to any one of claims 1-6.

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