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78 results about "Low-cycle fatigue" patented technology

Low cycle fatigue has two fundamental characteristics: plastic deformation in each cycle; and low cycle phenomenon, in which the materials have finite endurance for this type of load. The term cycle refers to repeated applications of stress that lead to eventual fatigue and failure; low-cycle pertains to a long period between applications.

Method for rapidly evaluating service life of turbine cooling blade based on flight parameters

The invention discloses a method for rapidly evaluating the service life of a turbine cooling blade based on flight parameters, and belongs to the technical field of aero-engines. The method comprises the following steps: acquiring a load spectrum, a material, a structure and working state parameters of the turbine blade; establishing a blade finite element model and performing fluid thermosetting coupling analysis to obtain temperature field and stress field distribution; determining a dangerous part of the blade based on the temperature field and stress field distribution; respectively establishing a creep durability model, a low-cycle fatigue model and a fretting fatigue life model for dangerous parts; and finally, updating the model based on load spectrum data monitored in real time, and calculating the residual life of the blade. According to the method, the intrinsic performance of the material is associated with the characteristic structure of the blade, and the efficient life prediction model is constructed based on limited test data, so that the life consumption of the turbine blade is quickly and accurately evaluated according to actual flight parameters.
Owner:NORTHWESTERN POLYTECHNICAL UNIV

Anti-buckling tool for low-cycle fatigue test sheet metal structure

The utility model relates to the technical field of low-cycle fatigue tests, and discloses an anti-buckling tool for a low-cycle fatigue test sheet metal structure, which comprises a fixing assembly and a guide assembly, the fixing assembly comprises an upper fixing piece I, an upper fixing piece II, a lower fixing piece I and a lower fixing piece II, two screws are connected between the first upper fixing piece and the second upper fixing piece, two screws are connected between the first lower fixing piece and the second lower fixing piece, and cushion blocks are arranged on the inner side faces of the first upper fixing piece, the second upper fixing piece, the first lower fixing piece and the second lower fixing piece. Through the fixing assembly, the sample can be conveniently and quickly assembled, the low-cycle fatigue test requirement of the sheet metal structure can be met, and the lateral buckling instability phenomenon between a clamping part of equipment and the buckling-restrained tool can be reduced; through the guide assembly, when the sample bears a tension and compression cyclic load, the lateral buckling instability phenomenon in the thickness direction is prevented, and the stability of the sample is further enhanced.
Owner:GUOHE GENERAL (QINGDAO) TEST & EVALUATION CO LTD

Clamping device for thin-wall whole pipe fatigue test and test method

The invention provides a clamping device for a thin-wall whole pipe fatigue test and a test method, and belongs to the technical field of clamping devices. The device comprises clamping cushion blocks which are fixedly connected to two ends of a thin-wall whole tube sample main body and are used for transmitting test force; the high polymer material film adhesive tape is wound on a transition area of the clamping cushion block and the thin-wall whole pipe sample main body; the chock plugs are used for being plugged into the two ends of the thin-wall whole-tube sample main body, and packing paper is installed between the chock plugs and the inner wall of the thin-wall whole-tube sample main body and used for supporting the inner wall of the sample and evenly transmitting test force. The clamping cushion blocks are fixedly connected to the two ends of the sample and matched with the high polymer material film adhesive tape to reduce friction, the chock plugs are wound around the packing paper to support the inner wall, a stable clamping structure is formed, and it is ensured that fatigue fracture occurs in the working section. The problems of clamping stress concentration and fracture of a non-working section can be effectively avoided, the accuracy of a fatigue life evaluation result of the whole thin-wall pipe is improved, and the method can be widely applied to high-cycle and low-cycle fatigue performance tests under different conditions.
Owner:NCS TESTING TECHNOLOGY CO LTD

Wall type Z-shaped metal torsion tube damper anti-seismic system and method

The invention discloses a wall type Z-shaped metal torsion tube damper anti-seismic system and method. The wall type Z-shaped metal torsion tube damper anti-seismic system comprises a frame beam, a frame column, a cantilever wall and a Z-shaped metal torsion tube damper. The frame beams and the frame columns are connected with a building, the cantilever walls are connected with the frame beams, and the Z-shaped metal torsion tube dampers are arranged between the paired cantilever walls and connected with the cantilever walls so as to dissipate energy transmitted by the cantilever walls. According to the damper anti-seismic system, the Z-shaped metal torsion tube damper is arranged to replace a traditional mild steel metal damper and a viscous damper to conduct damping design of a building structure, the problem that the low-cycle fatigue performance of the traditional metal damper is poor is solved, the oil leakage risk of the viscous damper is avoided, and the anti-seismic performance of the building structure is improved. Moreover, due to the structural design in the damper, the influence of the bending and shearing effect on the deformation of the torsion tube under the action of an axial load is eliminated, so that the section of the torsion tube is always kept a stable circular section in the hysteresis energy consumption period of the torsion tube, and the energy consumption efficiency is ensured.
Owner:CHINA CONSTR FIFTH ENG DIV CORP LTD +1

Data-physical hybrid driven hydrogen-induced fatigue life prediction method

The invention discloses a data-physical hybrid driven hydrogen-induced fatigue life prediction method, which comprises the following steps: S1, selecting different hydrogen storage steel lining materials, respectively carrying out a tensile test and a low-cycle fatigue test before and after hydrogen charging, collecting mechanical property parameter data, fatigue parameter data and fatigue life, and calculating the fatigue life of the hydrogen storage steel lining materials according to the mechanical property parameter data, the fatigue parameter data and the fatigue life; carrying out normalization processing on the collected data; s2, constructing a cascade PINN model composed of a BP model and a PINN model; s3, the non-hydrogen-filled mechanical property parameters serve as input, the hydrogen-filled mechanical property parameters serve as output, and a BP model is constructed; the hydrogen charging mechanical property parameters output by the BP model and the fatigue parameters serve as input of a PINN model together, the fatigue life under the hydrogen charging working condition serves as output, and the PINN model is constructed; and taking a prediction result finally output by the PINN model as the fatigue life under the hydrogen charging working condition. According to the method, the fatigue life of the hydrogen storage steel lining material stored for a long time can be rapidly predicted.
Owner:CHINA UNIV OF MINING & TECH

Method for predicting high-low cycle composite fatigue life of turbine box of aviation supercharger

The invention relates to an aviation supercharger turbine case high-low cycle composite fatigue life prediction method, which comprises the following steps: firstly, determining the working state parameters of a supercharger under the start-stop cycle of an aviation piston engine, then calculating the stress strain of dangerous parts of the supercharger turbine case under different working conditions through a simulation model, decomposing the high-low cycle fatigue load spectrum of the supercharger, and calculating the fatigue life of the supercharger; determining parameters of an S-N curve and an epsilon-N curve of a turbine box material, and predicting the high-low cycle composite fatigue life of the turbine box on the basis. The method can scientifically determine the high-low cycle composite fatigue life of the turbocharger turbine box in the design stage or the use process of the turbocharger turbine box, can be used for reliability analysis and life evaluation of the turbocharger turbine box, guides the structure optimization design and reasonable use of the turbocharger turbine box, and has a good application prospect. And therefore, the reliability and the safety of the aviation turbocharger in the working process are ensured.
Owner:CHINA NORTH ENGINE RES INST

A method for establishing a prediction model of low-cycle fatigue life of exhaust heat end

The application discloses a kind of prediction model establishment methods of exhaust heat end low cycle fatigue life, comprising the following steps: according to engine at different power, set different exhaust heat end model thermal boundary condition;According to each boundary condition respectively to exhaust heat end model is carried out stress field analysis, obtains the strain table of the maximum equivalent plastic strain increment of exhaust heat end and the temperature table of the maximum equivalent plastic strain increment corresponding node;According to the maximum equivalent plastic strain increment of exhaust heat end determines exhaust heat end life check component;Based on the temperature value in temperature table respectively to check component carries out high temperature tensile test and cold thermal shock cycle test, obtains the static tensile table of the material of life check component under corresponding temperature and test life table;According to static tensile table, test life table and strain table determine the prediction model of exhaust heat end, to predict the fatigue life of exhaust heat end, it is convenient to set up reasonably for the overhaul and replacement cycle of exhaust heat end.
Owner:DONGFENG MOTOR GRP

A method for predicting multi-axial low cycle fatigue of cast stainless steel

ActiveCN117725702BFatigue loadingShear stress
The application particularly relates to a cast stainless steel multiaxial low-cycle fatigue prediction method, which comprises the following steps: measuring or calculating the axial strain amplitude and the corresponding axial stress, the shear strain amplitude and the corresponding shear stress, and the phase difference between the axial strain amplitude and the shear strain amplitude of a cast stainless steel concerned part; calculating the equivalent axial strain amplitude and the equivalent shear strain amplitude of the cast stainless steel concerned part after correction and containing the influence of thermal aging; and substituting the equivalent axial strain amplitude and the equivalent shear strain amplitude of the cast stainless steel concerned part after correction and containing the influence of thermal aging and the phase difference therebetween into a cast stainless steel multiaxial low-cycle fatigue prediction model containing the influence of thermal aging to calculate the multiaxial low-cycle fatigue life and the fatigue crack direction of the cast stainless steel after thermal aging. The cast stainless steel multiaxial low-cycle fatigue prediction method can accurately predict the fatigue life of the cast stainless steel under multiaxial low-cycle fatigue loading and the direction of fatigue crack initiation and initial propagation.
Owner:CHINA NUCLEAR POWER OPERATION TECH CORP

A method for rapid prediction of thermal-mechanical fatigue life of metal materials based on hysteretic energy density

The present application relates to the field of material science and engineering application technology, specifically to a kind of metal material thermal mechanical fatigue life fast prediction method based on hysteresis energy density.First, hysteresis curve is used to calculate hysteresis energy density, then the quantitative relationship between shape coefficient, stress variation range and plastic strain range between low cycle fatigue and thermal mechanical fatigue is used, to achieve the purpose of predicting thermal mechanical fatigue hysteresis energy density under the same mechanical strain amplitude by low cycle fatigue, finally, energy accumulation damage model is used to predict thermal mechanical fatigue life.The method carries out two groups of experiments for low cycle fatigue and thermal mechanical fatigue respectively, realizes the prediction of thermal mechanical fatigue life under different mechanical strain amplitudes by low cycle fatigue, establishes the correlation between low cycle fatigue and thermal mechanical fatigue by using the similarity between them in the process of cyclic loading, effectively reduces the experimental amount required for thermal mechanical fatigue life evaluation, and is applied to the thermal mechanical fatigue life prediction of high-temperature alloy and vermicular cast iron and other metal materials.
Owner:INST OF METAL RESEARCH - CHINESE ACAD OF SCI

Transient characteristic-containing maneuvering and pneumatic extreme value load combination probability distribution research method for multi-duct casing system

The invention discloses a transient characteristic-containing maneuvering and pneumatic extreme value load combination probability distribution research method for a multi-duct casing system, and relates to the technical field of aero-engines, and the method comprises the steps: processing an original maneuvering load spectrum through employing a filtering method based on rain flow counting, extracting a typical task segment, and completing distribution fitting; acquiring basic data of a maneuvering load and an aerodynamic load; a turning point sequence of the basic data of the maneuvering load and the aerodynamic load is extracted, time domain reconstruction is carried out, and rain flow counting and low-cycle fatigue damage verification are carried out; carrying out mass sampling on the reconstructed load spectrum, and analyzing maneuvering and pneumatic extreme value load distribution characteristics; and calculating the correlation coefficient of the dynamic load and the aerodynamic load by adopting a rain flow method to obtain the joint probability density of the maneuvering load and the aerodynamic load. According to the method, the transient load analysis precision and efficiency of the multi-duct casing are improved, and theoretical support and data basis are provided for structural design and fatigue life prediction.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Prediction method and system for unified damage low-cycle fatigue life

The invention provides a unified damage low-cycle fatigue life prediction method and system, and relates to the technical field of material tests.The method comprises the steps that stress and strain information of current and adjacent moment increment steps of a crack expansion area is obtained, damage opening displacement is constructed according to the stress and strain information, and the damage opening displacement is input into a unified cohesive force model; monotonic and cyclic fatigue damage evolution quantities are output; uniformly representing the two damage evolution quantities, determining a total damage accumulation value of cohesion unit nodes, sequentially judging monotonous and cyclic fatigue damage failure, deleting the nodes and recording moments if the monotonous and cyclic fatigue damage failure is failed, and updating cohesion rigidity if the monotonous and cyclic fatigue damage failure is not failed; and updating the boundary conditions of the model, performing iterative execution until a preset time increment step number is reached, extracting crack length change information to construct a life curve, and finally determining a low-cycle fatigue crack propagation life prediction result.
Owner:BEIJING INST OF TECH

An aero-engine compressor blade service damage evaluation method

PendingCN122389424AAviationFatigue loading
This invention relates to a method for evaluating service damage of aero-engine compressor blades, solving the problem that current blade performance testing cannot obtain test values ​​'d' through direct sampling from the blade. The method comprises the following steps: S1: Design the dimensions of the blade simulator; S2: Select a base material consistent with the blade; S3: Calculate the maximum temperature and maximum stress of the blade under different service conditions, based on the blade's design status; S4: Statistically count the number of Category I low-cycle cycles, Category III flight takeoff cycles, and Category IV powered takeoff cycles for at least 10 engines, and calculate the conversion factors for each type of cycle using the temperature and stress calculation values ​​under different service conditions to obtain the equivalent number of cycles for different service times; S5: Apply low-cycle fatigue loading, fixing and clamping the simulator, and performing low-cycle cyclic loading according to the stated temperature, stress, and number of cycles; S6: Take samples from the low-cycle fatigue-treated specimen and perform tensile and high-cycle fatigue mechanical property tests. This invention significantly reduces the need for collecting blade service conditions and parameters, greatly reducing workload.
Owner:STATE-OWNED SICHUAN WEST MASCH FACTORY +1

Friction stir welding method for strengthening low-cycle fatigue performance of high-strength aluminum alloy joint

The invention relates to a friction stir welding method for strengthening the low cycle fatigue performance of a high-strength aluminum alloy joint. The friction stir welding method comprises the steps that a copper base plate with the heat conductivity being 300-500 W / m.K is laid in a tool groove used for friction stir welding; a pair of high-strength aluminum alloy plates to be welded are fixed in a tool groove, butt joint friction stir welding is conducted under the welding conditions that a stirring head rotates anticlockwise, the dip angle ranges from 2 degrees to 3 degrees, the rotating speed ranges from 300 rpm to 400 rpm, and the welding speed ranges from 60 mm / min to 120 mm / min, and the friction stir welding direction is consistent with the rolling direction of the high-strength aluminum alloy plates to be welded; in the friction stir welding process, the bottoms of butt welding seams of a pair of high-strength aluminum alloy plates to be welded are placed on a copper base plate, and the cooling rate during friction stir welding reaches 20-100 DEG C / s; the non-uniformity of the structure of the cross section of the welding seam is greatly reduced, namely, the strength and the low-cycle fatigue performance of the welding seam are improved.
Owner:NORTHWESTERN POLYTECHNICAL UNIV

A fatigue test load debugging method for a main hub central part of an unmanned helicopter

The application provides a fatigue test load debugging method for a main hub central part of an unmanned helicopter, comprising the following steps: establishing a mechanical model according to a preset test loading scheme, and calculating theoretical values of a flapping force and a pitching force required to be applied to reach a target load; performing parameter configuration and parameter debugging on each load channel of a coordinated loading control system; performing static load and dynamic load working condition debugging on the main hub central part, so that the static load and the dynamic load meet test requirements; and on the basis of the static load and the dynamic load debugging of the main hub central part, performing low-cycle fatigue test load and high-cycle fatigue test load debugging on the main hub central part, so as to obtain input loads of a flapping force actuator and a pitching force actuator meeting test requirements. The technical scheme of the application solves the problem that the existing fatigue test mode of the main hub central part cannot guarantee that the loads of the hub center and the butt joint surface of the arm of the main hub central part meet test requirements at the same time.
Owner:CHINA HELICOPTER RES & DEV INST

A double-sided friction stir welding joint and a welding method and application thereof

The application belongs to the technical field of magnesium alloy solid-phase connection, and discloses a double-sided friction stir welding joint and a welding method and application thereof, which comprises the following steps: first friction stir welding is performed on pretreated magnesium alloy plates; the magnesium alloy plates after the first friction stir welding are turned over by 180 DEG, coaxially centered, and then second friction stir welding is performed symmetrically to obtain the double-sided friction stir welding joint. The application realizes the improvement of the low-cycle fatigue performance of the magnesium alloy joint, the improvement of the deformation coordination and the weakening of the basal texture induced by multidirectional plastic flow, the synergistic effect of the uniform and refined structure, the defect elimination and the texture weakening, the direct change of the macro-mechanical response of the joint under the low-cycle fatigue load, and the systematic and substantial improvement of the low-cycle fatigue life of the magnesium alloy double-sided friction stir welding joint.
Owner:XI'AN UNIVERSITY OF ARCHITECTURE AND TECHNOLOGY

Method for predicting service life of coiled tubing under cooperation of plasticity and damage

The method for predicting the service life of the coiled tubing under the cooperation of plasticity and damage is characterized in that the fatigue service life and the strain amplitude under the specific curvature radius are obtained through a full-size bending fatigue test, and the fatigue service life and the strain amplitude are substituted into a Manson-Coffin model to invert an unknown coefficient; the method comprises the following steps: determining mechanical parameters of a material in combination with a uniaxial tensile test, constructing a finite element mechanical model, carrying out finite element simulation on bending working conditions of a damaged coiled tubing on a roller and a guider, extracting strain amplitudes, and further establishing strain amplitude calculation models under different working conditions by adopting a Levenberg-Marquardt algorithm; coupling the model with a Manson-Coffin equation, and respectively constructing fatigue life prediction models of the roller and the guider; and on the basis of the Miner theory, three times of bending cycles with different curvatures in one trip are regarded as complete load cycles, an accumulated damage value is calculated, a correction coefficient is determined through low-cycle fatigue finite element simulation, a calculation model of the number of remaining trip times is established, and quantitative prediction of the remaining life is achieved. The method is suitable for the technical field of petroleum and natural gas drilling engineering.
Owner:SOUTHWEST PETROLEUM UNIV

Method and system for predicting service life of heat-resistant steel based on low-cycle fatigue crack evolution and fracture

The invention belongs to the technical field of heat-resistant steel life prediction, and discloses a heat-resistant steel life prediction method and system based on low-cycle fatigue crack evolution and fracture, and the method comprises the steps: collecting the original structure morphology of austenitic heat-resistant steel, and obtaining the average grain size and grain orientation characteristics; and calculating the maximum Schmidt factor and the minimum Schmidt factor of each crystal grain by traversing a crystal grain slippage system. Meanwhile, a dislocation slippage theory is taken as a core, a low-cycle fatigue test is combined, shear stress, friction stress, Poisson's ratio and a plastic strain range are introduced, a low-cycle fatigue slippage zone length c and a crack tip fatigue slippage length increment delta CTSD are calculated, elastic and plastic strain tensors and a fatigue hysteretic curve are fused, and a crack tip fatigue slippage zone length delta CTSD is calculated. The crack growth rate and the crack length change rule under different circulation cycles can be accurately obtained, and the prediction error of a general model is reduced. The prediction accuracy of the fracture life of the austenitic heat-resistant steel can be greatly improved, potential safety hazards and resource waste are reduced, and stable operation of equipment under the high-temperature working condition is guaranteed.
Owner:TIANJIN UNIV

A method for predicting the probabilistic low-cycle fatigue life of a turbine blade

The application discloses a kind of probability low-cycle fatigue life prediction methods of turbine blade, it is related to blade life prediction technical field.Acquire the multiple groups of sample working condition data of turbine blade to be predicted, and the low-cycle fatigue life of turbine blade to be predicted under each group of sample working condition data is calculated respectively by fatigue life prediction model based on critical plane method;Through multiple groups of sample working condition data and corresponding low-cycle fatigue life, neural network is trained, and low-cycle fatigue life prediction model is obtained;Through Monte Carlo method, the multiple groups of candidate working condition data of turbine blade to be predicted are generated, and the life prediction result corresponding to each group of candidate working condition data is predicted by low-cycle fatigue life prediction model;According to multiple life prediction results, the probability low-cycle fatigue life prediction result of turbine blade to be predicted is determined.The method can improve the accuracy of probability low-cycle fatigue life prediction while improving the efficiency of blade probability low-cycle fatigue life prediction.
Owner:XI AN JIAOTONG UNIV

High-strength steel plate for hydrogen transport steel pipe and its manufacturing method, and high-strength steel pipe for hydrogen transport and its manufacturing method

Provided is a high-strength steel plate for hydrogen transport steel pipes that has excellent fatigue crack propagation resistance, little deterioration in strength and elongation, excellent low-cycle fatigue properties, and excellent resistance to ground movement in a high-pressure hydrogen environment. The present invention provides a steel sheet having a predetermined component composition and a tensile strength (TS) in air. A ) and tensile strength in hydrogen gas environment (TS H ) is 535 MPa or more, and the tensile strength in air (TS A ) and tensile strength in hydrogen gas environment, elongation in air (EL A ) and elongation in hydrogen gas environment (EL H ), the yield ratio (YR), which is the ratio of the yield strength to the tensile strength of the steel plate in air and hydrogen gas environments, the minimum grain size of the top 20% of the largest grains at the center of the plate thickness, the number of repeated fractures in a low-cycle fatigue test with a strain amplitude of 3%, and the stress intensity factor range ΔK are all within specified ranges.
Owner:JFE STEEL CORP

Sub-model-based complex component creep-low cycle fatigue life rapid prediction method

The invention discloses a submodel-based complex component creep-low cycle fatigue life rapid prediction method, which comprises the following steps of: firstly, establishing a global simplified model of a complex component to carry out macroscopic response analysis; then, based on the stable cycle response characteristic shown by the specific high-temperature alloy under the creep-low cycle fatigue combined load, the boundary condition of the dangerous point sub-model is accurately defined; finally, through efficient and high-resolution sub-model analysis, rapid and accurate evaluation of the service life of the complex component under the creep-low cycle fatigue coupling effect is realized.
Owner:INST OF AEROSPACE TECH CHINA AERODYNAMIC RES & DEV CENT

Blade high-low cycle fatigue test equipment and method thereof

This invention discloses a blade high- and low-cycle fatigue test device and method that can accurately collect high- and low-cycle fatigue test data and reduce the difficulty of the test. To solve the above-mentioned technical problems, this invention provides the following technical solution, including an experimental chamber with an upward opening, a sealing cover at the upper end of the experimental chamber, a drive motor fixedly connected to the upper end of the sealing cover, a vertically arranged drive motor shaft extending downward into the experimental chamber, a blade disk detachably connected to the lower end of the drive motor shaft, test blades connected to the outer edge of the blade disk, a plurality of liquid nozzles arranged perpendicular to the upper surface of the blade disk and cooperating with the test blades on the sealing cover, an upward-opening oil collection hood on the outer side of the blade disk, the oil collection hood having a funnel-shaped structure, a vacuum oil tank connected to the lower end of the oil collection hood, a vacuum oil pump connected to the vacuum oil tank and a delivery pipe delivering vacuum oil to the upper end of the liquid nozzles.
Owner:AVIC TOUCHSTONE TESTING TECHNOLOGY (DACHANG) CO LTD

Method for predicting thermal fatigue life of BGA (Ball Grid Array) packaged solder ball

The invention provides a BGA packaging solder ball thermal fatigue life prediction method comprising the following steps: constructing a geometric model of a BGA packaging structure according to obtained geometric information of the BGA packaging structure to be predicted, and carrying out grid division; a low-speed tensile test and a low-cycle fatigue test are respectively performed on a low-speed tensile sample and a low-cycle fatigue sample, so that related experimental data are obtained; determining parameters related to the genetic algorithm, and fitting the true stress strain result of the low-speed tensile test and the test result of the low-cycle fatigue according to the parameters related to the genetic algorithm to obtain Anand constitutive model parameters and Darveaux life model parameters; according to the Anand constitutive model parameters and the Darveaux life model parameters, determining the thermal fatigue life of a solder ball in the BGA packaging structure to be predicted; the method has the beneficial effects that a set of complete experiment-fitting-simulation-prediction process is established, so that the method can adapt to simulation prediction of different materials and different structures.
Owner:SHANGHAI JIAOTONG UNIV

A design optimization method for a turbine blisk coupling structure based on confidence reliability

The application discloses a design optimization method of a turbine disc coupling structure based on confirmed reliability, and belongs to the technical field of structural part design optimization.The design optimization method of the application identifies key positions, performance parameters and failure mechanisms through qualitative analysis; constructs a subject cross equation, establishes mapping of internal cause variables and external cause variables to stress and strain; constructs a performance degradation model based on low-cycle fatigue, creep and coupling effects, and obtains total damage of a single task; further constructs a performance margin degradation model, quantifies internal and external cause uncertainties and establishes a confirmed reliability function.On this basis, parameter sensitivity analysis is carried out, sensitive design parameters are identified, and optimization design is carried out with reliability as the center.From the perspective of reliability, the application comprehensively considers performance margin degradation and multi-source uncertainty, can quickly and accurately identify key design parameters, realizes forward optimization design of the structure, and effectively improves the reliability and life of the turbine disc coupling structure under complex working conditions.
Owner:BEIHANG UNIV +1

Preparation and application of steel wire ceramic film layer based on ultrasonic-assisted micro-arc oxidation technology

The invention relates to preparation and application of a steel wire ceramic film layer based on an ultrasonic-assisted micro-arc oxidation technology, and belongs to the field of material surface treatment. According to the method, a high-concentration meta-aluminate solution is used as a micro-arc oxidation electrolyte, a steel wire is used as a micro-arc oxidation anode, an annular inert electrode is used as a micro-arc oxidation cathode, micro-arc oxidation with low current density, low temperature and long-time treatment is carried out, and multi-probe uniform weak ultrasonic treatment is carried out on the micro-arc oxidation electrolyte while micro-arc oxidation is carried out; and finally, a uniform micro-arc oxidation ceramic film layer with high bonding strength and high density is generated on the surface of the anode in situ. The prepared ceramic film layer can improve the marine corrosion resistance on the premise that the low-cycle fatigue characteristic of the ceramic film layer is not affected, and the method can be used as a surface treatment method for the steel wire and the rigging thereof for ocean engineering.
Owner:HUAZHONG UNIV OF SCI & TECH

Method for measuring crack growth rate and threshold value at extremely high temperature

PendingCN121977950AExcellent online measurement resolutionThe test repeatability dispersion coefficient is smallPreparing sample for investigationMaterial strength using repeated/pulsating forcesPotential measurementLow-cycle fatigue
The invention discloses a method for measuring a crack growth rate and a threshold value at an extremely high temperature. Firstly, a test sample and a clamp are manufactured; then a high-temperature furnace is installed, a test sample and a thermocouple are installed, the test sample, a reference sample and a potential measurement system are connected through a high-temperature-resistant wire, and the reference sample is arranged outside the high-temperature furnace; the temperature of the high-temperature furnace is raised to 1000-1200 DEG C, heat preservation is conducted, and meanwhile water cooling is conducted to the cooling connecting rod; the low-cycle fatigue testing machine starts to load and test the crack of the sample through a potential measurement system; a K-drop method is adopted for testing, a potential measurement system monitors crack propagation in real time through a direct-current potential method, the test is ended when the crack propagation rate reaches 1 * 10 <-mm > / cycle, and a fatigue crack propagation threshold value is obtained through data processing. According to the invention, the problems of current conduction stability, load transmission accuracy and crack length measurement accuracy in the environment of 1000-1200 DEG C are solved.
Owner:GUOBIAO BEIJING TESTING & CERTIFICATION CO LTD

Double-performance disc transition area cross-scale design method taking fatigue life as constraint

The invention discloses a double-performance disc transition area cross-scale design method taking fatigue life as constraint. According to the method, the low-cycle fatigue life prediction method considering the microstructures is established and combined with the macroscopic turbine disc model, cross-scale analysis from stress-strain distribution of the macroscopic turbine disc structure model to energy distribution of the microcosmic grain structures is achieved, and the low-cycle fatigue life of the microstructures at different positions is determined in combination with the microcosmic energy criterion. And finally, designing the transition area position of the dual-performance disc based on the principle of maximum utilization of fatigue life reserve, so as to obtain a final scheme for partitioning different organizations of the dual-performance disc. According to the method, the microstructure characteristics (such as strengthening phase, twin boundary and coarse and fine crystal mixing) of the material can be considered, and the macroscopic material level can be analyzed; in addition, according to the method, the fatigue performance difference caused by different microstructures of the dual-performance disc can be fully considered, and the fatigue life of the final design result is greatly prolonged compared with that of an existing scheme.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Determination method of low-cycle fatigue life prediction model based on strain rate sensitivity, prediction method and related device

PendingCN121766030ALow cycle fatigue lifeAccurate prediction of weekly fatigue lifeDesign optimisation/simulationStrain energyLow-cycle fatigue
The invention discloses a method for determining a low-cycle fatigue life prediction model based on strain rate sensitivity, a prediction method and a related device, and relates to the field of fatigue life prediction of high-temperature structural materials.The method comprises the steps that firstly, a reference strain rate is selected, and a uniaxial tensile test is conducted on a sample component; obtaining net tensile hysteresis energy and low-cycle fatigue life of different strain amplitudes at the reference strain rate; and based on the data, utilizing a classic energy life model to obtain a material constant parameter. And performing a uniaxial tensile test on the sample component to obtain the tensile plastic strain energy density of each strain rate in the strain rate range. And obtaining a change factor of each strain rate based on the tensile plastic strain energy density of each strain rate. And based on each strain rate change factor, the material constant parameter and the classical energy life model, obtaining a corrected energy model of each strain rate. According to the method, the low-cycle fatigue life of the material in a wide strain rate range can be accurately predicted.
Owner:EAST CHINA UNIV OF SCI & TECH

Turbine damping blade life prediction method, system and equipment and storage medium

The invention discloses a turbine damping blade life prediction method, system and device and a storage medium, and the method comprises the steps: determining uncertainty parameters affecting the fatigue failure of a turbine damping blade of a gas turbine, and building a multi-source uncertainty parameter sample library; establishing a turbine damping blade fluid-solid coupling analysis model, obtaining a thermal-mechanical stress-strain field calculation result of the turbine blade, extracting a stress-strain value of the dangerous assessment part, and calculating to obtain a low-cycle cycle number; establishing a thermal-mechanical stress-strain reconstruction network based on the convolutional neural network, and obtaining stress-strain field global reconstruction results of the suction surface, the pressure surface and the tenon teeth of the blade body; a fatigue life evaluation network fused with the physical law is established, and a blade base material low-cycle fatigue life prediction result is obtained; and inputting the dual-module deep neural network into a multi-source uncertainty parameter sample library, carrying out global sensitivity analysis on uncertainty parameters, and obtaining probability distribution characteristics of the low-cycle fatigue life of the turbine blade of the gas turbine.
Owner:XIAN THERMAL POWER RES INST CO LTD

Low-cycle fatigue life prediction method and system suitable for directionally solidified turbine blade

PendingCN121389370AMachine part testingGeometric CADTurbine bladeEffective strain
The invention discloses a low-cycle fatigue life prediction method and system suitable for a directional solidification turbine blade, and relates to the technical field of gas turbine key component life determination, and the method comprises the steps: obtaining to-be-measured data of the directional solidification turbine blade; the data to be measured comprises elastic modulus and low-cycle fatigue performance data; calculating an orientation factor based on the elastic modulus; determining effective strain energy density based on the low-cycle fatigue performance data; and calculating the predicted low-cycle fatigue life of the directionally solidified turbine blade based on the orientation factor and the effective strain energy density. The method can improve the prediction precision of the low-cycle fatigue life of the directional solidification turbine blade.
Owner:EAST CHINA UNIV OF SCI & TECH +1