70 results about "Fatigue limit" patented technology

The invention relates to a fatigue limit rapid prediction method based on infrared thermal image energy dissipation characteristics. The method comprises the steps of 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. The method comprises the following steps: monitoring steady-state temperature rise rates under different stresses through a thermal infrared imager, establishing a relation curve between a dissipation rate and a stress amplitude, predicting a fatigue limit based on a least square method, and comparing the fatigue limit with an S-N test result for verification. Compared with a traditional method, the method has the advantages of high prediction precision, high response sensitivity, low loss, short test period and the like, and is particularly suitable for rapid fatigue limit prediction and strengthening effect judgment of the high-temperature alloy material subjected to laser-assisted ultrasonic rolling strengthening.

The invention provides an additive repair blade high-cycle fatigue limit prediction method based on random defect probability distribution, and relates to the field of aero-engine fan and compressor blade maintenance, and the method comprises the steps: obtaining the defect distribution of a real blade; establishing a prediction model based on a critical distance theory; according to the prediction model, critical distances of the multiple real blades are determined, and a first critical distance is generated; performing defect reconstruction based on the defect distribution of the real blade to generate a virtual blade; obtaining the first high-cycle fatigue strength of the virtual blade according to the defect distribution of the virtual blade, the first critical distance and the prediction model; respectively determining a plurality of defect parameters and a Pearson coefficient of the first high-cycle fatigue strength, and screening a first parameter significantly related to the first high-cycle fatigue strength; constructing a fatigue strength evaluation model; and inputting the first parameter into the trained fatigue strength evaluation model, and outputting the predicted high-cycle fatigue strength. According to the scheme, the high-cycle fatigue limit of the blade can be quickly predicted, and the prediction accuracy is improved.

Disclosed are a wire rod and a steel wire for a spring, a spring with improved strength and fatigue limit, and a method for manufacturing the same. The disclosed wire rod for a spring with improved strength and fatigue limit according to an embodiment includes, in percent by weight (wt%): 0.6 to 0.7% of C, 2.0 to 2.5% of Si, 0.2 to 0.7% of Mn, 0.9 to 1.5% of Cr, 0.015% or less of P, 0.01% or less of S, 0.01% or less of Al, 0.01% or less of N, 0.25% or less of Mo, 0.25% or less of W, 0.05% to 0.2% of V, 0.05% or less of Nb, and the balance of Fe and unavoidable impurities, wherein Mn+Cr≤1.8% and 0.05 at%≤Mo+W≤0.15 at% may be satisfied.

The application provides an aero-engine blade high-cycle fatigue limit prediction method, first, parameters of a blade subjected to impact-corrosion coupling damage are measured, a fractal dimension and a stress concentration coefficient are calculated, the equivalent stress is corrected by using the fractal dimension and the stress concentration coefficient, a corrected critical distance model is obtained, and the fatigue limit of the blade subjected to coupling damage is predicted and calculated by using the corrected critical distance model. The blade high-cycle fatigue limit prediction method provided by the application innovatively integrates the three-dimensional fractal dimension, the theoretical stress concentration coefficient and the stress gradient distribution function near the notch root into the same model, and the blade fatigue limit obtained by the prediction calculation is highly consistent with the measured value of the test.

The application provides an aero-engine blade fatigue failure analysis method, first, the foreign object damage morphology data of the real blade is collected to form a real blade database, then the design parameters of the simulation blade are obtained according to the morphology and stress distribution of the real blade, and then the finite element model of the simulation blade is established, the modal calculation is carried out, whether the inherent frequency of each order mode meets the set requirement is verified, if the set requirement is met, the foreign object damage simulation of the finite element model of the simulation blade is carried out, the simulation result is obtained, and the consistency verification is carried out with the real blade database, finally, the real model of the simulation blade is made, the FOD test and the HCF test are continuously carried out on the real model of the simulation blade, and the fatigue limit of the real model of the simulation blade after damage is obtained. The method takes the foreign object damage morphology data of the real blade as the reference, realizes the high-cycle fatigue limit test of the foreign object damage simulation blade which is closer to the real working condition, has low cost, high controllability of parameters, and good interpretability.

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 present invention provides a method for preparing a high-modulus, high-strength, and high-fatigue-resistant aluminum-based composite sheet. The method comprises subjecting an in-situ ceramic particle-reinforced aluminum-based composite material to a sequential semi-continuous casting, hot rolling, cold rolling, solution treatment, cold rolling, and aging treatment. The method for preparing the aluminum-based composite sheet provided by the present invention features a simple and rational process. The non-uniform distribution of in-situ ceramic particles forms a two-stage heterogeneous structure with a non-uniform grain distribution, achieving a multi-layered reinforcement structure and a microstructure that inhibits fatigue crack propagation. This method simultaneously improves the elastic modulus, tensile strength, fatigue limit strength, and fatigue crack propagation resistance of the aluminum-based composite sheet, and can be industrially produced using existing industrial equipment.

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 present invention enables the magnitude of stress generated at a fixed part of a double member to be equal to or less than a fatigue limit, and does not cause an increase in the size of a component and the difficulty of processing. In the present invention, a second member (6) includes a curved surface portion (6d) having, as a starting point (6d1), one end portion (6a1) in a direction along a center line (1A) of an outer peripheral surface (6a). The first member (1) includes: a pressed surface (1g) formed by pressing a peripheral edge portion (1c2) of an inner peripheral surface (1c1); and a plastic deformation part (1x1) that is plastically deformed further inward in the radial direction than the outer peripheral surface (6a) of the second member (6). When a circle (C1) is drawn, the radius of which is the length (R1) of a line segment (LS1) connecting the starting point (6d1) and the radially outer end point (1g1) of the surface to be pressed (1g), and the center of which is the radially outer end point (1g1) of the surface to be pressed (1g), the circle (C1) intersects the curved surface portion (6d). An angle ([theta] 1) formed between a tangent line (LS2) that is in contact with the curved surface portion (6d) at an intersection (CP) between the circle (C1) and the curved surface portion (6d) and a line (LS3) that is orthogonal to the center line (1A) is greater than 0 DEG.

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.

The embodiment of the invention relates to a structural member fatigue judgment method and device and simulation equipment, and the method comprises the steps: obtaining the information of a structural member, building a finite element model according to the information of the structural member, carrying out the random vibration response analysis of the finite element model, and obtaining the inherent frequency and RMS data; acquiring vibration duration and material parameters of the structural member, and calculating to obtain a fatigue limit value according to the vibration duration, the material parameters and the inherent frequency; obtaining a first judgment result according to the fatigue limit value and the stress result of the RMS data on the structural member, and when the RMS data is greater than the fatigue limit value, performing accumulated damage analysis on the structural member to obtain a second judgment result; and according to the first evaluation result and / or the second evaluation result, determining a joint risk level of the structural member. According to the method, the risk degree of the structural member can be determined, the risk area can be determined, and a direction is provided for optimization and improvement of the risk area.

The present application relates to a kind of high reliability gear fatigue limit fast test method based on reliability conversion coefficient, specific steps include: carrying out gear fatigue strength up-down method test, obtains reliability conversion coefficient based on mathematical statistics method;Develop Locati method fatigue test, obtain fatigue test point;Based on reference fatigue S-N curve processing Locati method test result, obtain the gear fatigue limit under 50% reliability;According to the gear fatigue limit under 50% reliability, the reliability conversion coefficient is applied to evaluate the gear fatigue limit under high reliability.Solve the problem that the required test sample size is large, the cost is high, and the test cycle is long to obtain high reliability gear fatigue limit, while reducing the test amount, can maintain the high-precision evaluation result;It can be easily applied to engineering practice, and provides efficient method support for gear anti-fatigue and high power density design.

The present application relates to the technical field of aero-engine, and discloses a kind of blade vibration fatigue test analysis method and system, by using the way of gradient stress test to the vibration fatigue test analysis of the multiple test blades of the test blade type, obtain the test stress value before the crack of corresponding test blade under each test stress and the cycle number when crack occurs, to this analysis obtains the fatigue strength of each test blade;Finally, mathematical statistics is introduced, according to the fatigue strength of each test blade, the number of test blades and test stress gradient, the test results are analyzed, and the statistical minimum fatigue strength of the test blade type is obtained.The test sample required by the step method is less, generally only 3-6 test blades are used as test samples, and the fatigue limit test results obtained by the pass method are more accurate, which is suitable for the case that the test sample is less and the fatigue limit accuracy is high.

The invention discloses an additive manufacturing metal material fatigue life and fatigue limit prediction method and device. The method comprises the steps that microscopic structure parameters of a metal material subjected to first temperature set heat treatment are obtained; the metal material is obtained through additive manufacturing; the first temperature set comprises a plurality of temperature values; obtaining an S-N curve of the metal material subjected to heat treatment; the S-N curve is obtained through a fatigue performance test; establishing a fatigue life prediction model based on the microscopic structure; fitting the fatigue life prediction model by using the microscopic structure parameters and the S-N curve of the metal material, and solving a fitting coefficient; and utilizing the solved fatigue life prediction model to predict the fatigue life and the fatigue limit of the metal material at the second temperature under different stresses. According to the method, the relation model of the microscopic structure parameters and the fatigue performance is successfully established, and the prediction effect is excellent. Parameters required by prediction are easy to obtain, and compared with a prediction model established based on fracture analysis, the model is higher in anti-interference capability.

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 invention relates to a turbine blade stress concentration part high-cycle fatigue limit prediction method, and relates to the technical field of turbine blade fatigue life analysis, and the method comprises the steps: determining the root radius of a target stress concentration part according to the geometric parameters of the target stress concentration part in a simulation part; determining a target stress distribution function according to the root radius of the target stress concentration part, and determining a first maximum stress value of the target stress concentration part according to the target stress distribution function; determining a reference stress value of the target stress concentration part, and determining a stress concentration coefficient of the target stress concentration part according to the reference stress value and the first maximum stress value; and determining a second maximum stress value of the target stress concentration part according to the stress concentration coefficient, and predicting the fatigue limit of the stress concentration part simulation part according to the second maximum stress value. The accuracy of the fatigue limit value is improved.

The application provides a high-performance, fatigue-resistant nano-particle reinforced magnesium alloy and a preparation method thereof, and comprises the following steps: uniformly mixing Ti powder and B4C powder to obtain mixed powder 1; uniformly mixing the mixed powder 1 with Al powder according to three different molar ratios to obtain mixed powders 2, 3 and 4; sequentially placing the three kinds of powders in a pure aluminum thin cylinder according to a certain mass ratio, and sealing the opening by using a packaging machine and laser welding to finally obtain an aluminum-coated mixed powder material; adding the aluminum-coated mixed powder material in a magnesium alloy melting process, and performing mechanical stirring and ultrasonic stirring under a protective atmosphere; and finally obtaining the high-performance, fatigue-resistant nano-particle reinforced magnesium alloy after slagging, pouring, cooling, solid solution and aging heat treatment, wherein the tensile strength of the magnesium alloy is greater than or equal to 332 MPa, the elongation rate is greater than or equal to 8.5%, the cycle number is greater than or equal to 3117614 times when the fatigue load is 90 MPa, and the fatigue limit is greater than or equal to 86 MPa, which is much higher than that of the existing commercial magnesium alloy, and is suitable for industrial production.

The present disclosure provides a method for evaluating the original fatigue quality of a notched member, and relates to the technical field of reliability design. The method comprises the following steps: obtaining a long crack propagation threshold value of the notched member, a long crack propagation threshold value, a fatigue limit and an elliptical geometric parameter of a fatigue source area of a smooth member based on test data obtained by conducting crack propagation tests and high-cycle fatigue tests on the notched member and the smooth member; determining an equivalent initial crack size of the smooth member; determining an equivalent circle parameter of the fatigue source area; determining a fatigue notch factor of the notched member according to the equivalent circle parameter of the fatigue source area, the elliptical geometric parameter of the fatigue source area and the equivalent initial crack size of the smooth member; and determining an equivalent initial crack size of the notched member according to the long crack propagation threshold value of the notched member, a geometric shape factor, the fatigue notch factor and the equivalent initial crack size of the smooth member. The present disclosure can accurately evaluate the original fatigue quality of the notched member based on different hole forming processes.

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.