37 results about "Fatigue limit" patented technology

This invention provides a novel vibration fatigue testing method for gas turbine blades. Addressing the problems of large specimen wear, long testing time, and limited results associated with traditional step-and-step stress loading methods for obtaining blade fatigue limits, this invention excites blade resonance on an electromagnetic vibration table using novel step-and-step stress loading techniques on identical blade specimens. While retaining the step-and-step matching standard, when limited test data cannot meet the matching requirements, a stress "concession" method is rationally applied based on the turbine blade structure and fatigue strength level to eliminate test data with significant stress deviations, thereby obtaining the median fatigue strength of blades from the same batch. This invention makes stress matching faster and more flexible, requiring only 2-3 stress levels to achieve a test fitting result with a confidence level of over 95%, demonstrating high accuracy. This method is applicable to fatigue limit tests of all gas turbine blades.

The application discloses a valve box processing method, comprising the following steps: S1, rough machining of a pressure pump valve box forge blank; S2, normalizing treatment; S3, first tempering treatment; S4, carbonitriding treatment; S5, precooling quenching treatment; S6, second tempering treatment; and S7, packaging. The application simultaneously permeates carbon and nitrogen into the workpiece in the form of carbonitriding to form a carbonitriding layer, on the one hand, carbon atoms enter the metal surface and combine with metal atoms to form carbide, thereby improving the hardness and wear resistance of the workpiece surface, and wear and scratches on the metal surface can be effectively prevented; on the other hand, the permeation of nitrogen forms a dense nitride layer on the workpiece surface, improves the corrosion resistance, and enables the workpiece to be applicable to a harsh environment during oil exploitation; and on the third aspect, the residual compressive stress of the carbonitriding layer can improve the fatigue limit of the workpiece, thereby improving the fatigue strength of the workpiece and reducing brittleness.

The invention provides a gas turbine compressor blade service life evaluation method based on high-cycle fatigue characteristics, and aims to solve the problem that fatigue tests under pure simulation and laboratory conditions cannot be effectively combined to meet the requirement of gas turbine blade type core component service life evaluation. According to the method, the strength condition and the vibration condition of the blade are determined through finite element analysis, then the stable attenuation law of the fatigue strength of the blade is obtained by actually measuring the vibration stress and the fatigue limit values of the blade in different use time periods, and the service life of the gas turbine compressor blade is comprehensively evaluated by taking the high-cycle vibration fatigue reserve as the standard. The method is not limited to a ship gas turbine compressor, is also suitable for effective evaluation of the service life of the moving blades of an industrial gas turbine and an aero-engine compressor, and can provide a fatigue reliability design direction for a new model.

The invention discloses a high-fatigue TC4 titanium alloy fine-grain bar for a blade and a preparation method of the high-fatigue TC4 titanium alloy fine-grain bar, and belongs to the technical field of titanium alloy machining. According to the method, firstly, a qualified TC4 titanium alloy cast ingot is obtained through three times of VAR smelting; secondly, the cast ingot is subjected to upsetting and drawing forging at the upper and lower heating numbers at the phase transformation point to obtain a middle bar blank A; then the intermediate bar blank A is subjected to short-time-space water boiling cold and heat treatment above the phase transformation point, and an intermediate bar blank B is obtained; performing low-temperature rolling on the intermediate bar billet B to obtain an intermediate bar billet C; then carrying out medium-high temperature finish machining on the intermediate bar billet C to obtain a target bar billet D; and finally, surface defects and oxide skin of the target bar blank D are removed, the high-fatigue TC4 titanium alloy fine-grain bar for the blade is obtained, and the bar has high-temperature strength and heat stability while the excellent fatigue performance (the room-temperature smooth high-cycle fatigue cycle number is larger than 1.0 * 10 < 7 > times, and the fatigue limit is larger than or equal to 600 MPa) is guaranteed.

This application provides a method and system for predicting the fatigue performance of composite materials based on infrared thermal imaging, belonging to the field of material mechanical property testing technology. The method includes determining the fatigue performance characterization parameters and corresponding static strength values ​​of the composite material to be predicted; constructing a fatigue performance testing system for the composite material; determining the progressively increasing fatigue loading stress and load; applying progressively increasing stress levels of fatigue cyclic loading to the composite material under a given cycle to obtain a temperature field sequence and extracting temperature characteristic parameters characterizing the material's energy dissipation state; based on the temperature characteristic parameters and a composite material damage infrared characteristic library, obtaining the temperature-damage characteristic-stress relationship of the composite material under each cyclic loading level; based on this relationship, obtaining the critical transformation stress of the composite material to be predicted, determining the fatigue limit, and obtaining the fatigue life-stress relationship for fatigue performance prediction. This scheme improves prediction efficiency and accuracy, and avoids misjudgment based on a single parameter.

The invention discloses a Bayesian probability fatigue strength evaluation method for a structural member with defects, and relates to the technical field of fatigue strength prediction of aerospace metal structural members. The method comprises the following steps: firstly, drawing a fatigue limit curve based on test data of a defective material sample, embedding a physical rule of an El Hadad curve through a synthetic data set, and establishing physical priori knowledge of a defect size and a fatigue strength behavior; training model parameters by using test data of the structural member, constructing a Bernoulli likelihood function, and matching an actual failure tag of the structural member; and finally, fusing the prior distribution and the likelihood function through the Bayesian theorem to obtain probability distribution after parameter updating, and outputting a predicted failure probability expected value and uncertainty. According to the method, material sample data containing defects are fused as physical prior based on the Bayesian theory, and the probability fatigue strength is evaluated through experimental data of a small amount of structural parts.

The invention discloses a rapid optimization design method and device for inherent frequency, buckling pressure, maximum stress and other key indexes of an elastic strip, and belongs to the technical field of rail fasteners. Comprising the following steps: acquiring a plurality of key parameters of the elastic strip, including buckling end contact rigidity, tail end contact rigidity, buckling limb length, buckling end arc radius, tail end arc radius and side limb arch height; adjusting at least one key parameter based on the established quantitative relationship between the parameters and the inherent frequency, buckling pressure and maximum stress of the elastic strip; and calculating the adjusted key indexes, and optimizing the key indexes until a preset target is met. According to the method, the influence rule of key parameters on various performance indexes, namely collaborative optimization design of the missile strip, is defined, so that the inherent frequency of the missile strip can be remarkably improved to avoid a resonance area on the premise of keeping compatibility with an existing fastener system, meanwhile, the working stress is controlled below the fatigue limit, enough fastening force is ensured, and the service life of the missile strip is prolonged. And the resonance fatigue fracture problem of the elastic strip is fundamentally solved.

The present invention provides a wire rod, steel wire, and spring which are excellent in strength and workability, can be easily nitrided even at high temperatures, and have improved nitriding properties and fatigue limit, and a manufacturing method thereof. [Solution] The alloy is composed of, by weight percent, C: 0.6-0.7%, Si: 2.0-2.5%, Mn: 0.2-0.7%, Cr: 0.9-1.5%, P: 0.015% or less, S: 0.01% or less, Al: 0.01% or less, N: 0.01% or less, Mo: 0.25% or less, W: 0.25% or less, V: 0.05%-0.2% or less, Nb: 0.05% or less, with the remainder being Fe and other unavoidable impurities, Mn+Cr≦1.8%, 0.05at%≦Mo+W≦0.15at%, and 1mm in the center of a cross section perpendicular to the length direction 2 The alloy is characterized in that the ratio of the area that satisfies one or more of C>0.85%, Si>3.0%, Mn>0.8%, and Cr>2.0% by weight is 10% or less.

The present application relates to a kind of fatigue limit fast prediction method based on infrared thermal image energy dissipation characteristics, containing sample preparation and pretreatment, fatigue loading stress level upper limit determination, infrared fatigue test and temperature rise data acquisition, thermal image data processing and temperature rise feature extraction, energy dissipation model construction, fatigue limit value prediction, error analysis and method verification.Steady temperature rise rate under different stresses is monitored by infrared thermal imager, the relationship curve of dissipation rate and stress amplitude is established, the fatigue limit is predicted based on least square method, and compared with S N Test results are compared and verified.Compared with traditional method, the method has the advantages of high prediction accuracy, high response sensitivity, low loss, short test cycle, etc., and is especially suitable for fatigue limit fast prediction and strengthening effect determination of high-temperature alloy material after laser-assisted ultrasonic roll strengthening.​

The application provides a turbine blade root extension vibration fatigue test piece and a construction method thereof. The method comprises the following steps: obtaining a real turbine blade, wherein the real turbine blade comprises a blade body, a root extension and a tenon; cutting the blade body of the real turbine blade to form a partial blade body, and cutting the tenon of the real turbine blade to form a complete root extension and a partial tenon; the cutting positions of the blade body and the tenon of the real turbine blade are such that the bending section modulus of the root extension position is the lowest, and the first-order natural frequency of the turbine blade after cutting is the same as or similar to that of the real turbine blade; machining a fixed clamping end head; and fixing the fixed clamping end head to the tenon position after cutting, thereby forming the turbine blade root extension vibration fatigue test piece. The method provided by the application can accurately obtain the fatigue limit data of the root extension position of the turbine blade.

The invention belongs to the technical field of aeronautical materials, and particularly relates to an aeronautical high-conductivity ultrahigh-strength aluminum alloy material and a preparation method thereof. Through the Zr-Er-Y multi-element microalloying synergistic effect, a coherent Al3 (Zr, Er and Y) nano dispersed phase is formed, grains are remarkably refined, recrystallization is inhibited, meanwhile, the Y element optimizes the grain boundary precipitated phase form, the grain boundary binding force is improved, and a structure foundation is laid for high toughness of the alloy. A cooperative treatment strategy of isothermal forging and pressing, water quenching and two-stage aging is adopted in the process, and high-density dislocation and water quenching freezing dislocation configuration is introduced in forging and pressing so as to retain deformation stored energy. Two-stage aging promotes uniform dispersion of a precipitated phase, efficient superposition of deformation strengthening and precipitation strengthening is achieved, and the strength and fatigue resistance are remarkably improved. And finally, the strength, the electric conductivity and the fatigue limit of the alloy are synchronously improved while the high plasticity is kept, the bottleneck of mutual restriction of the strength and the corrosion resistance is effectively broken through, and the harsh requirements of aerospace on high-strength, high-electric-conductivity and high-fatigue materials are met.

The application relates to a kind of underwater wellhead-conduit reliability evaluation method and system, define the fatigue limit state of wellhead and conduit;According to the value range of the parameter that influences the fatigue life of underwater wellhead and conduit, random sampling is carried out in the value range of all the parameters, forming several groups of discrete data of random variables, and each group of discrete data of the random variables is composed of the single discrete point of all parameters after sampling;The stress range of underwater wellhead and conduit under the action of each group of discrete points is obtained, and then the function function of fatigue limit state represented by random variable is obtained;Solve the function function, obtain the fatigue life reliability index value of underwater wellhead and conduit, and then carry out reliability evaluation.Compared with the prior art, the reliability index value after solving can reflect the wellhead fatigue reliability under the multi-source randomness, and the accuracy of evaluation is better.

This invention discloses a heat treatment process for structural steel used in wind turbine towers, comprising the following steps: heating the steel plate as a whole to 880~920℃, austenitizing and holding at that temperature for 1.0~2.0 min / mm plate thickness; dividing the steel plate into three virtual regions—a surface region, a transition region, and a core region—symmetrically on both sides along the thickness direction, and cooling each region independently; heating the steel plate to 450~550℃, holding for 1~3 hours, and then slowly cooling it in the furnace to below 300℃ before air cooling. This invention employs gradient zone cooling of the steel plate, achieving "one steel for three uses" under the conventional Q345 / Q355 composition system simply by differentiating heat treatment parameters. This avoids the complexity of procuring different grades of steel for different tower sections. Furthermore, the gradient transition region eliminates the interface of abrupt performance changes, and the residual compressive stress field introduced by the rapid cooling of the surface layer significantly improves the hardness, fatigue limit, and elongation after fracture of the steel plate.

The application discloses a high-cycle fatigue full-life-cycle PSN curve evaluation method based on small sample data, and specifically relates to the following steps: in the limited life zone, the relationship between the fatigue life standard deviation and stress under each stress level is utilized, and the maximum likelihood method is fused to obtain a relatively accurate life standard deviation, and the PSN curve of the limited life zone is fitted; in the infinite life zone, the fatigue sample pairing number is determined by using the ascending and descending method, the relationship between the fatigue limit and the cycle number is combined, the maximum likelihood method is utilized to obtain the probability distribution of the fatigue limit; the PSN curve of the high-cycle fatigue full-life-cycle is obtained by combining the PSN curve of the limited life zone and the fatigue limit under the corresponding survival rate. Meanwhile, the VBA development software is used to realize the automatic calculation, the PSN curve fitting, and the visual display of the calculation and fitting results. The application can simultaneously cover the dispersion in the limited life zone and the infinite life zone, and the calculation method is simple and clear, and is suitable for engineering application.

The application discloses a high-load roller bearing structure and material fatigue strength optimization and performance evaluation method, and relates to the technical field of bearing design and manufacturing. The method comprises the following steps: obtaining structure geometric parameters, heat treatment process parameters and chemical composition data of the bearing; calculating the hardening layer depth, surface hardness and residual stress distribution based on physical metallurgical rules; converting the microstructure features into the contact fatigue limit and stress correction factor; establishing a slice method contact mechanics model to solve the contact load distribution; taking the structure geometric parameters and heat treatment process parameters as double design variables, and taking the maximum fatigue life and the minimum heat treatment process cost as double objectives to construct a multi-objective optimization function; solving the Pareto optimal solution set by using a non-dominated sorting genetic algorithm; and evaluating the candidate schemes and generating an optimization report. The application solves the technical problem that the structure design and the heat treatment process are mutually separated and cannot be optimized in a cooperative manner in the prior art.

The application discloses an aero-engine coating treatment blade fatigue limit prediction method and belongs to the technical field of aero-engines. The method comprises the following steps: obtaining the stress-strain curve of a stainless steel blade substrate through a single-axis tensile test, determining the constitutive model of the coating through a nano-indentation inversion analysis method; carrying out a coating blade fatigue test on a vibration table; establishing a coating blade finite element model in Abaqus; simulating the fatigue test of the coating blade on the vibration table by using a finite element method; establishing a blade fatigue limit prediction model considering coating treatment; extracting the circumferential effective stress parameters of the dangerous point position of the coating blade; substituting the effective stress parameters into the established prediction model to obtain fatigue limit prediction results; and verifying the prediction results with the test results. The aero-engine coating treatment blade fatigue limit prediction method has the advantages that the influence of coating treatment on the fatigue performance of the blade is considered, the fatigue limit of the coating treatment blade can be predicted, and the prediction result has high precision.

The application discloses a high-fatigue TC4 titanium alloy fine-grain rod for blades and a preparation method thereof, and belongs to the technical field of titanium alloy processing. The application firstly obtains qualified TC4 titanium alloy ingots through three times of VAR melting; secondly, the ingots are upset-forged for multiple times above and below the phase transition point to obtain intermediate rod blanks A; then, the intermediate rod blanks A are subjected to short-time air-cooling heat treatment above the phase transition point to obtain intermediate rod blanks B; then, the intermediate rod blanks B are subjected low-temperature rolled to obtain intermediate rod blanks C; then, the intermediate rod blanks C are subjected to high-temperature finishing to obtain target rod blanks D; finally, the target rod blanks D are subjected to surface defect and oxide skin removal to obtain the high-fatigue TC4 titanium alloy fine-grain rod for blades. The rod guarantees excellent fatigue performance (room-temperature smooth high-cycle fatigue cycle times > 1.0 x 10 7 MPa) while taking into account high-temperature strength and thermal stability.

The application discloses a kind of weld point material SN curve acquisition method and device, it is related to material data analysis field, including the following steps: setting load test condition, the fatigue limit load of test material is determined, the relationship between the weld point force-test cycle number of test material is obtained;The strain gauge patch position near weld point is calculated, to calculate the strain at weld point;According to the fatigue limit load obtained by measurement, load consistent with the direction of unit force in simulation model, the strain at strain patch is calculated;The weld point simulation model is corrected and loaded with the unit force consistent with the direction of load test, output weld point unit force, further obtain weld point unit stress;Based on weld point unit force and weld point unit stress, the unit force-stress relationship of weld point is obtained, and the SN curve of weld point material is obtained by combining weld point force-test cycle number relationship.The application improves the accuracy of weld point durability analysis, is suitable for conventional metal, with universality.

The invention discloses a laser shock peening method for improving the fatigue limit of a DH36 high-strength steel welding seam. The method comprises the following steps: carrying out horizontal butt welding on two DH36 high-strength steel plates by using a flux-cored wire arc welding process; the tension-compression sample is cut off from the welding plate, a welding seam is located in the middle of the tension-compression sample, upper and lower surplus heights are ground away, the tension-compression sample is polished through abrasive paper, and the tension-compression sample is cleaned; clamping the processed and cleaned tension-compression sample on a clamp of a robot, and fixing the left side and the right side of the tension-compression sample; and setting process parameters, emitting laser from the laser port, penetrating through the restraint layer and the absorption layer and acting on the surface of the tension and compression sample, so that the tension and compression sample continuously moves along a set strengthening path, and the surface of the welding seam is strengthened. According to the method, the surface of the sample can be subjected to plastic deformation, surface layer grain refinement is caused, a hardened layer and residual compressive stress are introduced, the surface hardness and the residual compressive stress are remarkably improved, crack initiation and propagation are delayed, and therefore the high-cycle fatigue limit of the sample is effectively improved.

The invention discloses an additive part durability evaluation method, device and equipment, a medium and a program. The method comprises the steps that a target part is printed into a durability limit evaluation sample, and a basic sample is obtained through heat treatment and linear cutting; dividing the basic sample into a reference group and at least two experimental groups to obtain a reference sample and a contrast sample group; performing a rotary bending fatigue test on each reference sample and each contrast sample to obtain fatigue limit data under different processes; calculating a surface durability limit reduction coefficient of the experimental group by taking the fatigue limit of the reference group as a reference; and substituting the surface durability limit reduction coefficient as a fatigue limit correction factor into a safety margin calculation formula, and evaluating whether the fatigue durability meets the design requirements or not according to the safety margin. According to the embodiment of the invention, the influence of different surface processes on the fatigue performance is quantified through contrast tests, and the actual working condition is associated with the safety margin, so that a reliable basis is provided for additive part surface process screening, and the part failure risk is reduced.

The application relates to the technical field of testing devices, in particular to a high-cycle fatigue limit testing device, which comprises a testing table, a mounting plate arranged on the testing table, a driving extrusion plate one slidably arranged on the mounting plate and used for extruding testing springs, a driving element arranged on the testing table and connected with the driving extrusion plate one, which is used for driving the driving extrusion plate one to reciprocally move so as to perform n-cycle fatigue tests on a group of testing springs with a compression amount of 2x% each time, and a driving extrusion plate two slidably connected with the mounting plate. The driving extrusion plate one of the device is moved by the force alternately released by the springs on both sides, the load of the driving element is effectively reduced, and the service life of the driving element and the whole device is prolonged. Meanwhile, the driving extrusion plate one and the driving extrusion plate two can respectively perform fatigue tests on different spring groups with different cycle times and compression amounts, and the testing functionality and practicability are improved.

This invention relates to a method for predicting the flexural fatigue life of LSAM-50 considering the temperature-load coupling effect and fatigue limit constraints. Through a systematic innovation across the entire process from material forming, experimental design, data processing to model construction, it is the first to systematically introduce temperature variables and fatigue limit parameters into the flexural fatigue model. This enables an accurate description and quantitative prediction of the fatigue behavior of LSAM-50 under temperature-load coupling, effectively solving three major problems of existing models: failure to consider coupling effects, lack of fatigue limit characterization, and absence of a dedicated model for this ultra-large particle size material. This achievement can provide direct theoretical basis and key design parameters for the fatigue resistance design, life prediction, and integrated optimization of LSAM-50 and its pavement structures, thereby significantly improving the scientific rigor, reliability, and economy of long-life asphalt pavement design.

The present invention aims to provide a high-strength steel sheet having a tensile strength of 980 MPa or more, press formability, and fatigue resistance, and a method for manufacturing the same. The high-strength steel sheet has a composition defined by a certain formula with an MSC of 2.7 to 3.8 mass%, a microstructure containing a certain structure in a surface layer region from the surface of the steel sheet to a depth of 100 μm and in an internal region other than the surface layer region, a maximum height of surface roughness of the steel sheet of 30 μm or less, a tensile strength of 980 MPa or more, an uniform elongation of 6% or more, and a ratio of the 10 7 second plane complete fatigue strength to the tensile strength (fatigue limit ratio) of 0.45 or more.

The present invention discloses a method and apparatus for predicting the fatigue limit of an impact-corrosion coupled damaged structure based on the critical distance method. The method calculates a three-dimensional fractal dimension based on a planar image of the impact-corrosion coupled damaged structure, calculates a theoretical stress concentration factor based on the damage situation of the damaged structure, establishes a stress gradient correction function for the root of the damaged notch based on the three-dimensional fractal dimension and the theoretical stress concentration factor, searches a pre-generated material-critical distance table to obtain the critical distance corresponding to the current material of the damaged structure to be predicted, and establishes a three-dimensional model of the damaged structure to be predicted. When the error between the corrected stress corresponding to the critical point and the fatigue limit of the smooth specimen is within a predetermined threshold, the external load on the three-dimensional model becomes the fatigue limit of the damaged component to be predicted. The prediction process of the present invention is relatively simple, requires only linear elasticity analysis, and has relatively high prediction accuracy.

This application discloses a method, system, medium, and terminal for evaluating the fatigue limit strength of metallic materials, relating to the field of industrial manufacturing technology. Its main purpose is to improve upon existing methods for evaluating the fatigue limit strength of metallic materials that reduce the fatigue limit strength of smooth specimens by establishing a roughness correction factor. However, existing methods suffer from inconsistent accuracy in fitting the roughness correction factor, resulting in the corrected fatigue limit strength evaluation still failing to meet accuracy requirements. The method includes: obtaining the surface roughness parameters of the target component; retrieving a fatigue limit strength evaluation model matching the manufacturing material as the target fatigue limit strength evaluation model; calculating the fatigue limit strength of the target component based on the surface roughness parameters using the target fatigue limit strength evaluation model; and performing a structural safety margin assessment of the target component based on the fatigue limit strength to obtain the structural safety margin assessment result.

This invention discloses a 50t axle load freight car axle designed for use in cold environments at 1200MPa, comprising the following chemical components: C, Si, Mn, Cr, Ni, Mo, Nb, V, Cu, Ca, La, [N], and Al. It exhibits good fatigue resistance and excellent low-temperature toughness; the fatigue limit R of a smooth-surfaced specimen is [not specified]. fL Fatigue limit R of specimens with notched surfaces ≥450MPa fE With an impact strength of ≥380MPa and a longitudinal impact energy of KV2≥130J at -40℃, a lateral impact energy of KV2≥110J at -40℃, a longitudinal impact energy of KV2≥110J at -60℃, a lateral impact energy of KV2≥90J at -60℃, a longitudinal impact energy of KV2≥80J at -80℃, and a lateral impact energy of KV2≥60J at -80℃, it can be applied to 50t axle load freight vehicles operating in low-temperature environments above -60℃.

The present application relates to a kind of methods for determining temperature-load coupling effect under LSAM-50 mixture splitting fatigue equation, this method is through the test design of system, Weibull distribution test and temperature-stress bivariate equation construction, first realize the accurate description and quantitative prediction of the fatigue characteristics of LSAM-50 flexible base material under complex service environment, solve the problem that existing fatigue equation does not consider temperature-load coupling effect, does not contain material fatigue limit, and lack of suitable model for super large particle size LSAM-50 material, provide direct theoretical basis and key design parameters for LSAM-50 mixture fatigue resistance design, life prediction and material and structure optimization, improve the scientificity and reliability of long-life asphalt pavement design.

The invention discloses a method for determining the high-cycle fatigue reliability of a blade. The method comprises the following steps: manufacturing a zoom blade, a first test piece and a second test piece, constructing a first SN curve based on the first test piece, constructing a second SN curve based on the second test piece, and obtaining the fatigue limit of the first test piece and the fatigue limit of the second test piece according to the first SN curve and the second SN curve; obtaining a variable coefficient according to the fatigue limit of the first SN curve, constructing a blade SN curve based on the scaled blade, obtaining the fatigue limit of the scaled blade according to the blade SN curve, and determining a correction coefficient according to the fatigue limit of the second test piece and the fatigue limit of the scaled blade, obtaining the fatigue limit and the standard deviation of the real blade according to the fatigue limit, the correction coefficient and the variable coefficient of the first test piece; constructing a Goodman curvilinear equation to obtain an allowable vibration stress set, collecting to obtain an actual vibration stress set, carrying out statistical comparison to obtain a logarithmic difference value, and obtaining the high-cycle fatigue reliability based on the logarithmic difference value.

The application provides a kind of blade high-cycle fatigue limit prediction method considering corrosion damage, simulation modeling is carried out according to real blade, simulated blade is obtained by processing, real blade and simulated blade are placed in constant temperature corrosion solution, to simulate the corrosion condition of blade under real working condition, after obtaining blade of different corrosion time, stress-strain curve measurement and fatigue limit test are carried out on blade, and the prediction curve of corrosion time and fatigue limit is fitted according to fatigue limit data;The application provides a kind of method for simulating blade corrosion condition and predicting blade fatigue limit under laboratory conditions, compared with the fatigue limit prediction of traditional theoretical calculation and empirical formula, the blade fatigue limit closer to real working condition can be obtained.

This application discloses a method for predicting the low-cycle fatigue life of coated turbine blades based on equivalent stress. The method includes: introducing an equivalent stress model based on the stress-life relationship in the fatigue limit formula to obtain a fatigue life prediction model; and predicting the low-cycle fatigue life of the coated turbine blades based on this model. By innovatively attributing fatigue life degradation to the increase in equivalent stress caused by microstructural changes, and drawing on the stress-fatigue life relationship in the Basquin model, a fatigue life prediction model based on equivalent stress is finally established. This establishes a direct link between fatigue life and the morphological parameters of the interface microstructure and material properties, giving the model stronger physical meaning and universality, and achieving high-precision life prediction.