234 results about "Cyclic loading" patented technology

According to the offshore wind turbine single pile rigidity numerical simulation method considering long-term circulation and scouring, the accuracy and the calculation convenience are both considered in model building through the linear elastic steel pipe pile model and the Mohr-Coulomb soil body model. By calculating the horizontal ultimate bearing capacity of the single pile, combining the ultimate analysis method and the p-y curve calculation method, the influence of different scouring depths on the fan is considered, the horizontal load bearing capacity and inherent frequency evolution of the single pile are comprehensively measured, and a basis is provided for design and safety evaluation. A sandy soil rigidity attenuation model is established for secondary development of Abaqus and verified, and the rigidity change of sandy soil under long-term cyclic loading is considered, so that the simulation precision is improved. And the numerical model is tested and verified to ensure the reliability. And the accumulated lateral displacement of the steel pipe pile can be accurately predicted, the influence rule of cyclic load times, soil elasticity modulus and embedding depth factors on displacement development is disclosed, wind power engineering design optimization is assisted, and economical efficiency and safety are improved.

The invention relates to the technical field of material fatigue prediction, in particular to a material fatigue prediction method and system based on a physical guidance neural network, and the method comprises the steps: obtaining mechanical response data and material microstructure feature data in a material cyclic loading process; based on the mechanical response data and the material microstructure feature data, constructing a physical guidance neural network model; the method comprises the following steps: a) acquiring fatigue damage parameters through a physical constraint unit by utilizing a physical guidance neural network model; b) incorporating microstructure characteristics of the material into a fatigue damage evolution equation through an attention layer; c) quantizing the uncertainty of the fatigue damage evolution equation through an uncertainty quantization unit; d) obtaining a prediction result through a feature mapping unit; the prediction result is subjected to uncertainty quantification through the prediction unit, a final material fatigue prediction result is obtained, material mechanics knowledge is introduced into the neural network through the physical constraint unit, and it is ensured that the prediction result conforms to the basic physical law.

Disclosed in the present invention are high-rise pile cap equipment under a horizontal load and a centrifuge test method for foundation bearing characteristics thereof. The equipment comprises a model box, a sand layer, a model pile cap, at least eight model piles, a horizontal loading device, at least two laser displacement sensors, an axial force sensor, and a plurality of strain gauges. The method comprises: S1, performing one-way horizontal loading on high-rise pile cap equipment under a horizontal load to obtain an ultimate foundation bearing capacity situation, a model pile body axial force distribution situation, a pile foundation axial force comparison situation, a model pile body bending moment distribution situation, and a model pile body bending moment comparison situation of the equipment; and S2, performing one-way variable amplitude cyclic loading on the high-rise pile cap equipment under the horizontal load to obtain a foundation displacement situation, an effect of the number of cycles on foundation stiffness, an effect of a cyclic load amplitude on the foundation stiffness, and a foundation inclination situation. In this way, the foundation design of the high-rise pile cap can be optimized, and a basis and a reference for evaluating safety of foundation long-term service are provided.

The invention discloses a quasi-static loading system for plane local loading and a loading method of the quasi-static loading system, and aims to solve the problem that a processing method for accurately simulating a complex stress state of a shear wall under an equipment anchoring effect does not exist at present. A bottom-arranged boundary fixing piece is arranged at the bottom of a counter-force portal, and an out-of-plane local load loading assembly is arranged on the top surface of the bottom-arranged boundary fixing piece; the vertical loading piece and the in-plane horizontal transverse loading assembly are arranged in the counter-force portal frame, a placing part matched with a test piece is formed between the bottom side of the loading beam and the top surface of the bottom boundary fixing piece, the two horizontal actuators are arranged at the two ends of the loading beam respectively, one end of each horizontal actuator is connected with the loading beam, and the other end of each horizontal actuator is connected with the in-plane horizontal transverse loading assembly. The other end of each horizontal actuator is arranged on the inner wall of the side part of the counter-force gantry; the quasi-static force loading method comprises the following steps: performing preset vertical axial force application, prestress tension grading and / or supplementary tension treatment on a test piece according to preset requirements, and then performing horizontal cyclic loading until the bearing capacity of the test piece is reduced to 85% of a peak load, and terminating the loading process.

The invention belongs to the technical field of material performance testing, and particularly relates to a simplified test method, a prediction method and a prediction system for the crack arrest toughness of a material, and the test method comprises the following steps: obtaining a crack arrest toughness sample containing precracks of a target material and physical parameters of the sample under preset conditions; the method comprises the following steps: under a preset condition, carrying out multiple loading and unloading crack arrest toughness tests on a sample in an incomplete unloading manner to obtain loading and unloading test data in each loading and unloading process, the loading and unloading test data comprising load data, crack opening displacement data, cyclic loading times and crack length data; according to a preset validity verification condition, performing validity verification on the obtained loading and unloading test data, and screening and determining key parameter data for calculating crack arrest toughness; calculating crack arrest toughness data according to preset conditions, the key parameter data and the physical parameters of the sample; the testing method is simple, low in cost and high in efficiency.

The invention discloses an ultra-thin titanium plate electric auxiliary tension and compression cyclic loading device and a test method, the device comprises two outer side samples used in cooperation with an ultra-thin titanium plate sample, the two outer side samples are fixed on the two sides of the ultra-thin titanium plate sample, the two outer side samples and the ultra-thin titanium plate sample form a composite tension and compression sample, the ends of the ultra-thin titanium plate sample extend out of the ends of the outer side samples, and the outer side samples are fixed on the two sides of the ultra-thin titanium plate sample. The two sides of the composite tension and compression sample are fixed through the clamping assemblies and then are applied with lateral force; the two pairs of electric auxiliary clamps are clamped at the two ends of the composite tension and compression sample respectively, each pair of electric auxiliary clamps comprises two oppositely-arranged chucks, the clamping faces of the chucks are provided with conductive structures, the conductive structures are connected with an external power source, and when the composite tension and compression sample is clamped on the chucks, the conductive structures make contact with the composite tension and compression sample. The chuck is connected with the loading end part of the universal testing machine, and the ultrathin titanium plate sample can be prevented from being distorted and deformed in the testing process.

A detection method and device for predicting railway mud swells and mud leaks, comprising: step 1, obtaining a railway subgrade filling coefficient, a cyclic loading coefficient, and a radar detection coefficient; step 2, calculating a railway mud swell and mud leak risk value based on the subgrade filling coefficient, the cyclic loading coefficient, and the radar detection coefficient; and step 3, setting a risk value threshold, comparing the mud swell and mud leak risk value with the risk value threshold, and predicting the occurrence of mud swell and mud leaks when the mud swell and mud leak risk value is greater than or equal to the threshold. The present invention not only improves the accuracy of subgrade geological radar detection but also comprehensively considers subgrade filling and cyclic loading. Compared to existing technologies, the present invention comprehensively considers the three necessary conditions for mud swell and mud leaks, quantitatively and comprehensively predicting railway subgrade mud swell and mud leaks, meeting the requirements of resource conservation and quality and safety engineering construction.

The invention relates to the technical field of connection structure testing, in particular to a bridge deck slab dry joint connection structure testing method which comprises the following steps: preparing a bridge deck slab test piece containing a steel structure embedded dry joint; building a testing device, and arranging strain, displacement and pressure sensors in a dry joint area; carrying out a graded loading test, including static loading to 1.5 times of the designed bearing capacity and dynamic cyclic loading; an environment simulation test is carried out, and repeated loading is carried out in a temperature and humidity circulation box simulation environment; data are evaluated through a multi-source data fusion optimization algorithm model, and indexes such as flexural rigidity and shear rigidity are calculated; in addition, a construction stage simulation test is added, and the alignment deviation and the filling compactness of the components are monitored. According to the method, the structural performance can be comprehensively evaluated, key indexes can be accurately evaluated, durability degradation can be scientifically predicted, construction simulation is innovated, test conditions are guaranteed to be consistent, visualization and verification are achieved, and the problem of limitation of a traditional test method is effectively solved.

The invention discloses an oil and gas pipeline fracture phase field fatigue crack propagation calculation method, system, equipment and medium, and the method comprises the following steps: building a finite element model of a submarine oil and gas pipeline, and setting material parameters and fatigue fracture phase field calculation parameters; based on the finite element model, cyclic loading calculation is carried out by adopting a fatigue fracture phase field method; when detecting that the crack is about to generate catastrophic expansion, starting an arc length control algorithm on the finite element model, and performing combined solution on the displacement field, the load factor and the phase field by controlling arc length parameters; and outputting the fatigue life and the final fracture form of the pipeline according to the calculation results of the displacement field and the phase field. According to the method, the displacement increment, the load factor increment and the phase field increment are solved at the same time through the arc length constraint condition, and stable solving of multi-field cooperation is achieved. The intelligent switching mechanism ensures that calculation can still be steadily converged in a catastrophic propagation stage, and a complete crack propagation path and a final structural failure form are obtained.

The invention relates to the technical field of geotechnical experiment equipment, and discloses a coarse-grained soil lateral confinement dynamic compression instrument and an experiment method thereof. The electric cylinder is longitudinally arranged above the test piece bin, the pressing plate is arranged on a movable rod of the electric cylinder, the pressing plate is located in the test piece bin, and a water injection opening is formed in the pressing plate; the displacement sensor is arranged on a reaction frame of the pressure piece and used for measuring the axial deformation of the test piece, the force sensor is arranged on the test piece and used for measuring the load applied to the test piece, and the multiple pore pressure sensors are all arranged in the test piece and used for measuring the pressure distribution of the inner wall of the test piece; the coarse-grained soil lateral confinement dynamic compression instrument can reveal a deformation mechanism of a soil-rock mixture under the action of lateral confinement compression cyclic loading, and explores plastic cumulative deformation and excess pore water pressure change rules of a sample under different stone contents and loading amplitudes.

The invention relates to an incremental forming preparation device and method for preparing a thin-wall component with a double-gradient structure based on thermal coupling cyclic loading, and the device comprises a clamp supporting tool, a driving device and a rotatable tool head, the clamp supporting tool is used for clamping a to-be-formed plate, exerting back reaction force when the plate is formed in the forward direction and providing a supporting effect when the plate is formed in the reverse direction. The driving control unit adjusts the deformation condition of the local area of the plate through the motion state (pressing amount and rotating speed) and the motion track of the tool head, and the high-performance thin-wall forming part of the double-gradient structure with the grain forward gradient and the dislocation density reverse gradient in the thickness direction is prepared under the thermal-mechanical coupling cyclic loading condition. Compared with the prior art, the novel double-gradient structure is prepared through the thermal coupling incremental forming technology, the thin-wall formed part is prepared at the same time, the toughness performance of the formed part can be remarkably improved, the machining cost is effectively reduced, and the machining efficiency is improved.

This invention discloses a method and system for numerically defining a rebar-concrete interface element under both monotonic and cyclic loading, comprising: first, establishing a finite element model of reinforced concrete component, and generating a solver input file within the finite element software; then, adding a series of user-defined interface elements in the solver input file; then, inputting parameters of characteristic points of the axial bond-slip curve between rebar and concrete, the diameter of rebar, and the characteristic parameters of fibers associated with the user-defined element (UEL) in the solver input file; then, setting the element stiffness matrix, the coordinate transformation matrix and residual in the UEL subroutine; finally, submitting the solver input file in the finite element software, and calling the UEL subroutine for calculation.

The invention discloses a method for analyzing longitudinal force and longitudinal displacement of a long and large ramp continuously welded track under train braking, which comprises the following steps of: establishing an analysis / finite element model of the long and large ramp ballast track continuously welded track, taking initial ballast bed longitudinal resistance as an input parameter, and calculating to obtain initial distribution of longitudinal force and longitudinal displacement of a continuously welded track steel rail; meanwhile, the maximum value of longitudinal displacement of the continuously welded rail is obtained; and establishing a discrete element model of the long and large ramp ballast track seamless track, taking the maximum value of the initial distribution of the longitudinal displacement of the seamless track steel rail as an input condition, carrying out cyclic loading of the long and large ramp ballast track under the loading condition through a longitudinal displacement-longitudinal resistance dual-control method, extracting the longitudinal resistance of a track bed under the non-loading condition, and calculating the maximum value of the longitudinal displacement of the long and large ramp ballast track. And importing the data into the established analysis / finite element model to obtain updated distribution of longitudinal force and longitudinal displacement of the continuously welded rail. According to the method, the evolution characteristics of the longitudinal resistance of the long and large ramp ballast track seamless track ballast bed can be reasonably reflected.

The invention relates to the technical field of slope stability prediction, in particular to a slope stability evolution prediction method of a main shock and aftershock sequence cumulative damage mechanism. The method comprises the following steps: determining an initial strength parameter of a slope sliding surface rock-soil body and a dynamic strength attenuation parameter under the action of a main shock and aftershock sequence through an indoor cyclic load test, and establishing a cumulative damage model; three-dimensional side slope geometric features are obtained, and the spatial orientation and the stress direction of a potential sliding surface are determined; calculating a dynamic sliding force in combination with seismic oscillation parameters, and updating an effective strength parameter and a dynamic anti-sliding force of the sliding surface in real time; and carrying out staged calculation and dynamic evolution analysis by adopting a limit equilibrium method or a strength reduction method. According to the method, by introducing a rock-soil body strength accumulated damage and progressive attenuation mechanism under the cyclic action of the main and aftershock sequences, the damage accumulation process and the stability evolution law of the slope stability along with the development of the main and aftershock sequences are described, so that the progressive instability process and the accumulated instability risk driven by the aftershock after the main shock is triggered can be identified.

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.

The invention provides a brittle material cyclic loading and unloading test simulation method based on discrete elements. The method comprises the steps that a cyclic loading and unloading constitutive model used for describing the mechanical state of particles when a brittle material is affected by cyclic loading is constructed; based on a discrete element method and a cyclic loading and unloading constitutive model, inputting parameters and conditions, and if the time step length is not reached, calculating particle stress information; if the time step length is reached, directly outputting a calculation result and drawing a cloud picture; traversing all the particles, calculating the speed and displacement of the particles according to the stress information of the particles, outputting a calculation result, and drawing a cloud picture. According to the invention, reference can be provided for mechanical characteristics of cyclic loading and unloading tests of the fragile material, cyclic loading, fatigue and plastic failure of the fragile material under the cyclic loading condition can be reflected, and production safety in the construction process can be guaranteed; the technical problem that an existing cyclic loading and unloading test simulation method depends on experience judgment of linear regression and cannot meet the scene requirements of a nonlinear relation and plastic failure is solved.

The invention discloses a large-scale visualized direct shear test device and method for geosynthetics. The device comprises a main frame, an upper shear box, a lower shear box, a normal cyclic loading system, a horizontal cyclic shear loading system, a data acquisition system and a visualized monitoring system. The direct shear test device is characterized in that the direct shear test device can perform normal and horizontal cyclic loading at the same time, and normal stress with different frequencies and amplitudes can be applied according to needs to simulate a test of the characteristics of the reinforcement-soil interface under the cyclic loading effect; one side wall of the upper shear box and one side wall of the lower shear box are transparent observation windows, and a high-speed camera and a digital image analysis method are combined, so that the shear band evolution process can be visually observed and quantitatively analyzed; the shear box is large in size, and the size effect is effectively overcome. According to the invention, the interface characteristics under the cyclic load effect in the road engineering can be reflected more truly and comprehensively, the size and the function of the shear box are comprehensive, and the interface mechanical characteristics and the interaction mechanism under various working conditions can be simulated.

The invention belongs to the technical field of impact fatigue tests of metal materials, and relates to an impact fatigue test system for simulating a working condition environment of a gun firing pin, which can perform high-frequency cyclic loading of 200MPa-500MPa, microsecond (mu s) level impact pulse and more than kilohertz (kHz), and synchronously simulate the working condition environment. High-energy, high-frequency and short-pulse impact loading under the gun and gun firing pin working condition is carried out through the high-frequency impact generation subsystem, and the dynamic mechanical environment in actual service is effectively simulated; the environment simulation subsystem is used for accurately controlling the temperature, the concentration and the pH value of media such as salt mist and seawater, and is synchronously coupled with mechanical shock, so that mechanical-electrochemical synergistic damage conditions are truly represented; dynamic stress, strain, electrochemical parameters and surface topography in the impact process are synchronously monitored through a multi-parameter synchronous acquisition subsystem, and complete data support is provided for researching the damage evolution law of a material under a complex load; the repeatability and the safety of the test are ensured through the modularized sample clamp subsystem and the dynamic sealing design.

The invention relates to the technical field of geotechnical engineering anchoring, in particular to a method for testing the degradation characteristic of the bearing performance of a recyclable anchor rod under cyclic loading. The method comprises the following steps: preparing a unit body sample anchor-rock interface unit body sample, simulating weathered soft rock according to a specific ratio, pouring a self-compacting concrete anchoring body, and curing and forming; setting a combined parameter of a reference load ratio and a load cycle index, applying a triangular wave cyclic load to simulate a traffic condition, and executing a pull-out test to collect load-displacement data; constructing a two-parameter coupled shear strength degradation model based on test data, and proposing a shear stress-displacement curve model; an anchor rod load transfer control equation is established in combination with the Poisson effect, and shear stress distribution of the anchoring section is iteratively solved by adopting a discrete recursion method; the model is verified through a foundation pit engineering case, the ultimate bearing capacity degradation law of the anchor rod under long-term cyclic loading is predicted, and it is proved that the model can guide engineering safety design. According to the method, the coupling characterization of the cyclic load parameter and the interface degradation mechanism is realized.

The invention relates to the technical field of risk analysis, in particular to a water conservancy project risk assessment method based on big data, which comprises the following steps: acquiring deformation and water level signals and converting the signals into a sequence, generating an original monitoring sequence based on a timestamp, identifying a whole process span and intercepting and generating a periodic data set, generating a complete monitoring sequence by using interpolation filling, constructing a water level displacement closed curve, calculating a vector product difference value to obtain a geometric area, calculating an arithmetic mean value to generate a centroid coordinate, obtaining a dissipated energy increase coefficient and a structure permanent deformation cumulant, and generating an evaluation result based on threshold comparison. According to the method, the two-dimensional phase space model is established, the structure response is converted into the closed trajectory curve, the hysteresis loop area and centroid offset are calculated, energy dissipation and deformation accumulation of the structure under cyclic loading are quantitatively represented, abnormal plastic damage is effectively stripped, and early recognition of the potential irreversible damage risk of the structure is achieved.

The invention discloses a four-element model for modulus and creep of concrete under the action of long-period cyclic loading and a parameter determination method of the four-element model. The model simulates behaviors of concrete under the action of long-period cyclic load through four mechanical elements connected in series, and the four mechanical elements comprise an instantaneous elastic deformation element with rigidity increasing along with time, a recoverable creep viscoelastic element, an unrecoverable compression creep element and an unrecoverable tension creep element. According to the method, in order to overcome the difficulty that the available sample size of an application object is small, a step-by-step progressive mode is adopted, and classification and staged parameter calibration is carried out on the concrete modulus and a creep model of the application object.

This invention discloses a method and apparatus for fabricating complex hollow structures using pulsed DC and induction eddy current cyclic loading assisted diffusion bonding, relating to a method for assisted heating diffusion bonding. It achieves efficient and uniform heating of metallic materials. Step 1: Prepare a predetermined complex hollow metal structure to be diffuse bonded, polish and clean the surface of the complex hollow metal structure; Step 2: Place the complex hollow metal structure in a tooling mold for molding, and place the mold into a vacuum furnace; Step 3: Set up a dual-source control system; Step 4: Perform diffusion bonding under specified parameters, depressurize after the diffusion time is completed, and cool in the furnace until it reaches room temperature before removing the part. This invention combines pulsed DC heating and induction eddy current heating for diffusion bonding, improving diffusion efficiency while ensuring temperature uniformity, increasing the welding rate, and improving the quality of the diffusion joint.

The utility model discloses an integrated clamp for testing the tension and compression performance of a composite laminate after impact. The integrated clamp comprises a bottom plate, two side supporting plates, four side clamps, two middle anti-instability baffles, two bottom clamps, a top cover plate and two top clamps, in the tensile property test stage, a plurality of fifth screw holes are formed in the two ends of the test piece in the X-axis direction, and a plurality of first bolts penetrate through the third screw holes in the top clamp and the bottom clamp to be screwed into the fifth screw holes. According to the invention, through reasonable and exquisite cooperation and connection of the subsystems, the support can be simply, practically and effectively provided for the composite material laminate containing initial impact damage, so that the support is provided for stretching, compression and tension-compression cyclic loading performance tests after the composite material laminate is impacted.

The invention discloses a comprehensive simulation method for splitting failure of a Brazilian disk under dynamic and static actions. The method comprises the following steps: establishing a Brazilian disk finite element model and defining material parameters; performing dispersion crack treatment on the model through a phase field variable and a crack density function; selecting a branch path according to a load type (static / dynamic); the static branch constructs an energy functional and a displacement-phase field control equation based on an F-M variation principle, and the dynamic branch deduces a dynamic control equation through a Lagrange energy functional and a Hamiltonian principle; a displacement field and a phase field are updated through finite element discretization and Newton-Raphson iteration solution; cyclic loading is judged through convergence until the load is applied, and finally the crack propagation process and the mechanical response are visually output. According to the method, integrated simulation of dynamic and static loads is realized through a unified phase field dispersion framework, the problem of model incompatibility in a traditional method is solved, and the crack propagation prediction precision is remarkably improved.

The invention discloses a turbine disc alloy fatigue life prediction method considering residual stress relaxation evolution, which comprises the following steps: determining the size of a notch-containing simulation part of a turbine disc, and carrying out size optimization based on a dangerous point and a stress gradient; establishing a three-point bending finite element model, simulating a residual stress field and a work hardening field introduced by laser shock peening (LSP), and obtaining stress-strain states after a first period and a stable period through cyclic loading; compared with the prior art, the fatigue life prediction method has the advantages that by introducing the stress-strain state after the residual stress field is stabilized and combining a Walker index correction model, the problem of prediction deviation caused by neglecting subsequent relaxation in a traditional method is solved, the fatigue life margin is accurately evaluated, and the fatigue life prediction accuracy is improved. And an optimization basis is provided for the design of the turbine disc, so that the service cycle is prolonged within a safety threshold.

The invention discloses a super-precision spring performance monitoring method and system, and relates to the technical field of precision manufacturing, and the method comprises the steps: determining the static friction state of a contact surface between a super-precision spring and a supporting clamp after a compression force is applied to the super-precision spring; if the static friction state is that the contact surface of the clamp is lubricated abnormally, interface friction dissipation and spring body energy dissipation are calculated after axial circulation loading is executed on the super-precision spring; after the axial cyclic loading is paused and the compression force is applied again, a static friction coefficient is obtained; according to the interface friction dissipation, the spring body energy dissipation and the static friction coefficient, performance detection is conducted, and a performance detection result is obtained. According to the invention, the performance monitoring of the super-precision spring is realized, and the accuracy is improved.

The invention discloses an intelligent piezoelectric film hollow grouting anchor rod dynamic strain monitoring device and application thereof in underground engineering, and relates to the technical field of geotechnical engineering anchor rod monitoring. The main anchor rod system comprises a hollow inner steel pipe, a hollow anchor rod body arranged on the hollow inner steel pipe in a sleeving mode, a cavity formed between the hollow inner steel pipe and the hollow anchor rod body, a rubber ring and an external steel ring, and the rubber ring and the external steel ring are located at the two ends of the hollow anchor rod body and located in the cavity. According to the intelligent piezoelectric film hollow grouting anchor rod strain monitoring device provided by the invention, the distributed piezoelectric film is pasted in the hollow anchor rod body along the axial direction of the anchor rod, and the hollow steel pipe is arranged in the hollow anchor rod body, so that the basic performance of the hollow grouting anchor rod is reserved; and comprehensive real-time monitoring of dynamic strain generated by the anchor rod under high and low frequency vibration, instantaneous impact and cyclic loading is realized.

The present application relates to the technical field of high-temperature structural component fatigue strength design and life assessment, and particularly relates to a low-cycle multi-axial fatigue life prediction method based on powder high-temperature alloy damage mechanism. The method comprises: for the dangerous point of the component under non-isothermal multi-axial cyclic loading, calculating pure fatigue damage, pure creep damage and fatigue-creep interaction damage caused by a single load cycle; accumulating the pure fatigue damage, the pure creep damage and the fatigue-creep interaction damage to obtain the total damage of the single load cycle; taking the inverse of the total damage to predict the total failure life of the component under non-isothermal multi-axial cyclic loading. The method of the present application realizes effective prediction of the low-cycle multi-axial fatigue life of the powder high-temperature alloy component by accurately decomposing the damage of the dangerous point under non-isothermal multi-axial cyclic loading, can more truly reflect the comprehensive prediction model of the failure physics of the powder high-temperature alloy under multi-axial thermal mechanical loading, and improves the accuracy and reliability of the life assessment.

The present invention discloses a method for identifying the initiation, expansion, and fracture failure of asphalt fatigue cracks. The present invention uses a dynamic shear rheometer to perform a scanning test on an asphalt sample, collects torque T and deflection angle #imgabs0# data, and sequentially obtains the asphalt fatigue crack length a and the energy release rate G during the asphalt fatigue crack growth process. Finally, based on the evolution relationship between the asphalt fatigue crack length a and the number of cyclic loading cycles N, the dividing point between the fatigue crack initiation process and the expansion process is calculated, and the peak point of the energy release rate G is used as the critical point of asphalt fatigue failure. The present invention systematically solves the current problems of dividing asphalt into different fatigue stages under dynamic shear fatigue loads and determining the critical point of fatigue failure, and can finely analyze the fatigue process and behavioral characteristics of asphalt materials.

This invention discloses a method and system for predicting the creep fatigue behavior of martensitic heat-resistant steel, relating to the field of high-temperature creep fatigue performance evaluation technology. The method includes: acquiring the microstructure evolution of copper-containing martensitic heat-resistant steel during the test process, obtaining the cyclic strength change rate based on the microstructure evolution, and calculating the creep rate of the copper-containing martensitic heat-resistant steel in the dislocation climb hard phase, as well as the dislocation density under cyclic loading conditions; based on the cyclic strength change rate, creep rate, and dislocation density, obtaining the elastic strain tensor, plastic strain tensor, and creep strain tensor of the copper-containing martensitic heat-resistant steel, and predicting the stress-strain evolution of the copper-containing martensitic heat-resistant steel under cyclic loading conditions based on the elastic modulus tensor; this invention overcomes the limitations of macroscopic creep fatigue behavior prediction methods and provides a new approach to revealing the influence of microstructure on creep fatigue performance.