111 results about "Fatigue loading" patented technology

The invention discloses a wind generating set transmission chain fatigue load prediction method and system considering sandstorm characteristics, and belongs to the technical field of wind power generation and structure fatigue prediction. According to the method, a wind speed time sequence capable of representing sandstorm evolution characteristics is obtained and serves as external physical excitation to be input into a wind-machine-electricity coupling state space model, and a dynamic torque time sequence of a transmission chain low-speed shaft is obtained through calculation; on the basis, a load spectrum is generated by adopting a rain flow counting method, and the accumulated fatigue damage degree corresponding to the sandstorm event is calculated in combination with the Miner linear accumulated damage criterion and the S-N curve of the low-speed shaft material; and further comparing the damage degree with a preset threshold value, and when the damage degree exceeds the threshold value, automatically generating a preventive active load reduction control strategy aiming at the sandstorm, thereby realizing a closed loop of prediction and control. According to the method, the influence of extreme non-stable wind conditions such as sandstorm and the like on the fatigue damage of the transmission chain can be quantitatively evaluated, and technical support is provided for safe operation and predictive maintenance of a wind turbine generator in extreme weather.

The invention belongs to the field of airplane strength fatigue life prediction, and particularly relates to an equivalent stress-based airplane typical structure multi-axial fatigue life prediction method. The method comprises the steps of determining a typical aircraft high-lock connection structure test piece; determining a fatigue load spectrum; constructing a finite element model of the typical high-lock connection structure of the aircraft; determining a dangerous part of the airplane typical high-lock connection structure test piece in finite element analysis; determining the maximum principal stress at the dangerous part of the typical airplane high-lock connection structure test piece in finite element analysis; determining the fatigue life of the test piece; fitting S-N curve data under different stress ratios according to the fatigue life of the test piece and the load spectrum stress ratio, and determining a corrected S-N curve; determining an equivalent stress-life equation of the typical high-lock connection structure of the aircraft, and substituting the maximum principal stress and fitting parameters of the corrected S-N curve into the equivalent stress-life equation to calculate and obtain a fatigue prediction life; and correcting the fatigue prediction life according to a test result.

The invention discloses a wind turbine generator adaptive load shedding optimization control method and related equipment. The method comprises the steps of generating three-dimensional turbulent wind field data based on structure parameters and standard wind regime parameters of a wind turbine generator; carrying out aeroelastic coupling simulation based on the three-dimensional turbulent wind field data to obtain a load time sequence of each part under different working conditions, and determining a key part and a dominant load characteristic of the key part; taking the load time sequence of the key part and the reverse slope of the material as input, and calculating an equivalent fatigue load of the key part by using a rain flow counting method; according to the equivalent fatigue load, sensitivity of the key part to wind speed and turbulence intensity is analyzed, a sensitivity result of the key part is obtained, a sensitivity weight in a target function is set according to the sensitivity result, and a sparrow search algorithm is adopted to carry out parameter optimization on a PID controller; and the optimized PID controller is utilized to realize self-adaptive load shedding of the wind turbine generator under the complex working condition. According to the invention, load reduction optimization can be effectively realized.

The invention discloses a surrounding rock damage data analysis system and method based on multiple factors, and relates to the technical field of surrounding rock damage data simulation. A to-be-tested rock material is selected to prefabricate a closed crack group to form a stable roadway; setting different fatigue load intensities and cycle times, analyzing data changes of a stress field, a displacement field and acoustic emission under the action of the fatigue load based on an acoustic emission monitoring system, and determining a bearing performance change model; and real working conditions are simulated based on the bearing performance change model, a difference value between simulated data and real data is formed, an output target of fatigue load strength is intelligently corrected, and data compensation is realized for the bearing performance change model. According to the method, original defects such as joints and cracks in the rock mass and damage evolution under cyclic loads are included into an analysis framework, a reliable basis is provided for long-term safety and stability judgment of a roadway under cyclic load working conditions such as compressed air energy storage, and safe and efficient production of a coal mine is effectively supported.

The invention relates to the technical field of fatigue load reduction, in particular to a wind power plant torque and variable pitch cooperative control method with fatigue load reduction as the target. The method comprises the following steps: acquiring real-time and historical operation data of each fan in a wind power plant, and preprocessing the operation data; based on the preprocessed operation data, load characteristic indexes reflecting structural fatigue are extracted, and a load state vector reflecting the current fatigue accumulation trend of the draught fan is constructed; and based on the load state vector, establishing a coupling model of the influence of the generator torque and the variable pitch angle on the rotating speed response and the fatigue load, wherein the coupling model is used for reflecting the influence mechanism of torque adjustment on the low-frequency load and the inhibition effect of variable pitch adjustment on the high-frequency load. According to the method, the load state vector fusing the low-frequency mechanical load and the high-frequency pneumatic excitation is constructed, and the rain flow counting and equivalent damage theory is combined, so that the load component which has the greatest influence on the fatigue life of key parts such as a main shaft, a transmission chain, a tower and a blade root is accurately identified.

The invention discloses a method for predicting fatigue life of a high-temperature alloy electron beam welding joint by considering residual stress, which comprises the following steps of: on the basis of a traditional S-N curve of the welding joint, superposing the residual stress, and considering that the residual stress is released along with a fatigue load cycle number so as to correct the S-N curve. Firstly, a change curve of the residual stress attenuation rate Sr along with the cycle index in the fatigue loading process of the high-temperature alloy electron beam welding head is established, and a residual stress reduction coefficient K is obtained through calculation based on the Sr curve. The initial residual stress is corrected by introducing a reduction coefficient K, and the initial residual stress and external load stress are linearly superposed to establish a damage parameter, so that a welded joint fatigue life prediction model considering residual stress release is established. The model has relatively high life prediction precision, and compared with the mode that residual stress is not considered, the life prediction dispersion zone is improved from + / -3 times to + / -1.25 times.

The invention discloses a quantitative test method and system for a peak locked-rotor torque of a robot joint module, and relates to the technical field of robot joint performance evaluation, and the method comprises the steps: extracting a torque time-calendar curve of the joint module, defining the peak locked-rotor torque as a controlled low-frequency fatigue loading process, and building a mapping model of a torque amplitude and a failure cycle index; constructing a test system, and performing torque-current static calibration; embedding a specific excitation function in a current loop of the servo driver; the bus voltage and rotating speed change rate is monitored in real time, and the voltage and current impact at the unloading moment is inhibited by adopting a back electromotive force compensation algorithm and combining an energy consumption discharge loop; and repeatedly loading until the structure is damaged, recording the number of cycles, and drawing a peak torque-life curve as a basis for predicting the life of the whole machine. According to the method, quantitative association of the peak locked-rotor torque and the fatigue life is realized, quantitative evaluation from a static index to a dynamic life is realized, a basis is provided for life prediction of the whole robot, and the test precision is improved.

The present application belongs to the technical field of aircraft structure fatigue strength, and particularly relates to a method for converting a buffeting frequency spectrum of an aircraft structure into a fatigue load spectrum, comprising the following steps: Step 1: processing buffeting response load data of the aircraft structure to obtain a first-order bending modal characteristic frequency f1; Step 2: performing narrowband filtering on the buffeting response load data, and calculating a root mean square value σ of the filtered narrowband buffeting response load data; Step 3: performing rainflow counting on the filtered narrowband buffeting response load data to count the amplitude distribution of the narrowband buffeting response load data; fitting the amplitude distribution of the narrowband buffeting response load data with a Rayleigh distribution; and equivalently distributing the amplitude distribution fitted with the Rayleigh distribution to three typical load amplitudes; and Step 4: establishing a periodic step load spectrum according to the frequency of the three equivalent typical load amplitudes.

The application discloses a tower fatigue load accumulation method and system based on wind direction frequency distribution, and the method comprises the following steps: S1, acquiring the wind frequency distribution of each sector of a specific site location, the Weibull distribution parameters of each sector and the effective turbulence intensity of each sector; S2, obtaining the equivalent fatigue load corresponding to the tower circumference weld hot spot through load calculation; S3, sorting the wind frequency distribution of each sector and the equivalent fatigue load corresponding to the tower circumference weld hot spot; according to the fatigue curve index m of the material and the sorted parameters, equivalent conversion is performed on the equivalent fatigue load of all sectors to obtain the equivalent maximum value of the tower circumference; and S4, according to the equivalent fatigue load-stress relationship, the equivalent maximum fatigue damage of the tower circumference life cycle is calculated. The application has the advantages of effectively reducing the equivalent fatigue load of the tower weld, reducing the weight of the tower, saving the amount of steel material, reducing the investment cost of the wind power and the like.

The application discloses a component fatigue micro-damage early identification method based on a nonlinear static component, and particularly relates to the technical field of material nondestructive testing and structural health monitoring, which comprises the following steps: arranging an excitation probe and a receiving probe on the surface of a component to be measured; selecting an excitation frequency based on a frequency dispersion curve and generating a Hanning window modulated wave; collecting a propagation response signal; extracting a static component amplitude A and a fundamental wave amplitude A through time-frequency processing; calculating a nonlinear static parameter beta=A / A²; further calculating a first derivative S(N) and a second derivative ΔS(N) of beta with respect to a fatigue loading cycle N; and identifying a dislocation dominant stage, a dislocation saturation or rearrangement stage, a micro-crack initiation stage and a macro-crack formation stage according to the first derivative S(N) and the second derivative ΔS(N). The application can be used for early stage identification of the evolution process of component fatigue micro-damage.

An offshore wind power plant designed to reduce a fatigue load of a wind turbine includes an offshore structure, a plurality of wind turbines which is installed above the offshore structure to be spaced apart from each other with a predetermined distance and is supplied with a power through wind to produce electrical energy; and a turbine controller which controls at least one of a pitch movement and a yaw movement for the plurality of wind turbines.

The utility model provides a fatigue testing device for a rubber-tyred loader, which relates to the field of vehicle testing, and comprises a fixed base, a test bed, a clamping sleeve upper cover, a distribution beam and an actuator, the fixed base is fixed on the test bed, the clamping sleeve upper cover is detachably and fixedly connected with the fixed base, and the distribution beam is fixed on the fixed base. The clamping sleeve and the fixing base define an installation space capable of containing a hub, the hub is arranged in the installation space, and when the clamping sleeve upper cover and the fixing base are fixed in place, the clamping sleeve upper cover and the fixing base can clamp and fix the hub. The actuator is fixed on the test bed, the distribution beam is fixed at the output end of the actuator and detachably fixed on the bucket, and the actuator is used for carrying out fatigue test loading according to a set load spectrum; the clamping sleeve upper cover and the fixing base clamp and fix the hub, circumferential fixation of the hub is achieved, abnormal deformation and displacement of a tire in fatigue loading are replaced, force and displacement of parts such as a frame and a large arm are prevented from being absorbed by the tire, and mechanical analysis and testing of the loading machine are facilitated.

This application discloses a method, apparatus, equipment, medium, and product for predicting damage evolution based on dynamic order reduction, relating to the field of aero-engine health management and monitoring. The method includes: conducting finite element fatigue / creep-fatigue simulation tests on structural components covering stress states under various operating conditions, and extracting the time-physics field matrix from the finite element fatigue simulation results under each operating condition; dynamically reducing the order of the time-physics field matrix to reduce its dimension, obtaining a reduced-order matrix; constructing a reduced-order model; restoring the equivalent stress field distribution based on the reduced-order model to obtain the reduced-order physical field; predicting the damage distribution evolution and fatigue life under fatigue or creep-fatigue loading based on the reduced-order physical field, and making corrections based on the fatigue life prediction model. This application can improve the efficiency and universality of life prediction.

The invention relates to the technical field of structure testing, in particular to an overhead rigid suspension expansion joint fatigue test device and method, and the device comprises a fatigue host module which provides reciprocating vertical vibration power for an expansion joint; the comprehensive platform module is used for providing reciprocating horizontal vibration power for the fatigue host module; the control system module comprises a strain data processing unit which is used for constructing a three-dimensional strain field model and calculating stress distribution based on the strain data; the phase compensation generation unit dynamically generates lag compensation time of the horizontal vibration relative to the vertical vibration; and the driving control unit is used for adjusting the phase of the horizontal vibration in real time based on the lag compensation time, so that the horizontal vibration reaches the maximum displacement value at the vertical vibration peak moment. According to the invention, the authenticity, accuracy and reliability of the fatigue test of the expansion joint can be effectively improved, the phase and displacement synchronization of horizontal vibration and vertical vibration can be dynamically adjusted through a linkage control mechanism, and the spatial multidirectional composite fatigue load in actual operation can be reproduced.

The utility model discloses a fan blade swing fatigue testing device, and belongs to the technical field of fan blade fatigue testing. Comprising a blade clamping module and a fatigue loading excitation module. The fatigue loading excitation module comprises a plurality of groups of random wooden saddles used for clamping blades in an up-down matching manner, the random wooden saddles comprise upper random wooden saddles and lower random wooden saddles, upper steel plates are arranged at the tops of the upper random wooden saddles, lower steel plates are arranged at the bottoms of the lower random wooden saddles, and the upper steel plates and the lower steel plates are connected through studs; an excitation motor is arranged on the upper steel plate, and the output end of the excitation motor is connected with the eccentric mass block through a rotating arm. The blade fatigue testing device has the advantages of reducing testing energy consumption, improving blade testing efficiency, being suitable for fatigue testing of blades of different sizes, and being low in testing noise.

The utility model discloses a gear fatigue test fixture, which comprises a gear clamping part, a gear tooth loading part and a position adjusting part, and is characterized in that the gear clamping part comprises a gear left supporting plate, a gear right supporting plate, a clamping nut, a clamping bolt and a gear supporting plate fastening bolt; the gear tooth loading part comprises an upper pressure head, a lower pressure head, a lower pressure head height adjusting nut, a lower pressure head sleeve and a lower pressure head sleeve fastening bolt; the position adjusting part comprises a sliding platform, an adjusting lead screw, an adjusting hand wheel, a lead screw cover plate, a sliding platform fastening bolt and a fixed platform. The utility model also discloses a gear fatigue loading machine. According to the utility model, fatigue test requirements of gears with different diameters and different widths can be met.

The utility model discloses a biaxial fatigue test mold which comprises two clamping and loading assemblies, each clamping and loading assembly comprises a threaded sleeve, a sleeve, a deformation block and a clamping sleeve, and the deformation block is placed between the threaded sleeve and the sleeve; a clamping hole channel is formed in the deformation block; the threaded sleeve moves relative to the sleeve by rotating and screwing, and the generated displacement acts on the deformation block, so that the clamping hole channel of the deformation block annularly holds the pipe. One end of the clamping sleeve is connected with the sleeve, the other end of the clamping sleeve is connected with the fatigue machine, an oil injection pipe is arranged on the side face of the clamping sleeve, one end of the oil injection pipe is communicated with a cavity channel of the clamping sleeve, and the other end of the oil injection pipe is connected with an external oil source. And the external and internal parts of the pipe are simultaneously clamped and loaded, so that local high stress concentration generated on the surface of the pipe by a traditional mechanical clamp is reduced, and the accuracy of an experimental result is improved.

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.

The invention provides a discrete ballastless track tension-compression fatigue damage rapid calculation method, which comprises the following steps of: uniformly measuring a complex stress state and a simple stress state through a damage energy release rate, and decomposing tension-compression effective stress by utilizing a fourth-order projection tensor, so that the tension-compression effective stress value is equivalent to a uniaxial tension-compression stress value under a uniaxial loading condition; constructing a hyperbolic function with a natural constant as a base and a damage variable as an index on the basis of the damage energy release rate and in combination with three-stage damage characteristics of high-cycle fatigue of the material; carrying out integration on fatigue loading times through tension and compression damage, and deducing to obtain a discrete transcendental differential function of the damage related to the loading times; function variables are defined, an initial value is set, an iteration format is established, the discrete transcendental differential function is solved through a numerical integration method, and a calculation result graph is drawn. The model is simplified, and the calculation efficiency is improved; a high-order tensor stress updating algorithm does not need to be constructed, redundant calculation is reduced, and the data processing efficiency and the calculation speed during parameter analysis are greatly improved.

This application discloses a wind turbine operation control method, device, equipment, and storage medium, relating to the field of wind turbine generator control technology. The method includes: preprocessing initial pitch angle setpoints to obtain a target pitch angle setpoint time series; determining the inflection point positions of the target pitch angle setpoint time series and the change amplitude of adjacent inflection points to form a change amplitude set; determining the target change amplitude corresponding to a preset time period in the change amplitude set; and determining the number of target amplitudes from the target change amplitudes based on a preset amplitude threshold; determining whether the number of target amplitudes is greater than a preset number threshold; if greater, then controlling the target wind turbine to operate based on a preset low-fatigue operation mode. In this way, characteristic variables such as the pitch angle setpoint are used to equivalently describe the wind speed changes on the turbine rotor surface, thereby reducing fatigue load and improving the safety and stability of turbine operation.

This application discloses a wind turbine blade structure and a generator set. The wind turbine blade structure includes: a blade root section; a first connecting plate assembly, the first end of which is connected to the mating end face of the blade root section, and the second end extending along the blade axis in a direction away from the blade root section; a second connecting plate assembly, the first end of which extends along the blade axis toward the mating end face of the blade root section and is inserted into the first connecting plate assembly; and a blade tip section, which is connected to the second end of the second connecting plate assembly. In this application, the first connecting plate assembly and the second connecting plate assembly are pre-fixed at the mating end faces of the blade root section and the blade tip section, respectively, without damaging the main blade structure and without adding extra weight. Due to the absence of stress concentration caused by openings, the mechanical properties of the blade connection points are not reduced, and the blade can withstand fatigue loads and ultimate loads equivalent to those of a complete blade, thereby improving the mechanical properties of the blade.

This invention discloses a low-pressure casting and heat treatment process for high-strength and high-toughness aluminum alloy used in contact wire ratchet, belonging to the field of rail transit component manufacturing technology. The process uses AlSi7Mg0.3 alloy, obtaining high-purity aluminum liquid through two refining and modification treatments. In the low-pressure casting stage, a three-stage pressure control is adopted: the first stage is the liquid-raising stage, the second stage is the mold-filling stage, the third stage is the pressure-increasing and shrinkage-compensating stage, and finally, pressure holding and cooling are performed; followed by T6 heat treatment. This invention solves the casting problems of easy air entrapment in ratchet teeth and easy shrinkage porosity in the hub. The casting has a tensile strength ≥275MPa and a breaking load ≥94.5kN, meeting the requirements for a 2×10 contact wire ratchet. 5 Secondary fatigue load requirements.

The invention discloses a fatigue test crack detection method based on thermal imaging. In the periodic fatigue loading process, the surface temperature change of a sample is detected in real time through infrared thermal imaging, and an amplitude diagram and a phase diagram of weak temperature fluctuation are obtained through calculation; segmenting the sample through local phase consistency, prefabricating a gap and a background, and only performing subsequent analysis on a sample area so as to eliminate background interference; after the amplitude diagram is binarized, the boundary displacement influence is eliminated through a simple boundary displacement review strategy and by means of the boundary displacement direction and stress concentration point position relation, complex feature point matching and displacement estimation between images do not need to be conducted through the algorithm, the calculated amount is small, and reliability is high; the crack length is calculated according to the detected movement track of the crack tip feature point, the method does not depend on static crack features, the basic assumption that sample changes inevitably come from damage generation and development is utilized, and crack length evaluation is not affected even if wrong feature points are extracted through single-frame heat map analysis.

The application belongs to the field of crack image recognition in fatigue test, and particularly relates to a method for acquiring images at the moment of load peak value in fatigue test. The method comprises the following steps: collecting crack images, selecting reference frame images and target frame images; determining crack near-field regions of the reference frame images and the target frame images; extracting feature points of the crack near-field regions of the reference frame images and the target frame images, and performing feature point screening; calculating the reference feature point centroid and the target feature point centroid; calculating the offset of the target feature point centroid relative to the reference feature point centroid in the fatigue load loading direction; and selecting the target frame image corresponding to the maximum offset as the crack image corresponding to the moment of fatigue load peak value. The method for acquiring images at the moment of load peak value in fatigue test can independently and effectively recognize the image of the maximum crack opening state at the moment of fatigue load peak value.

The present invention provides a method for preparing a weld specimen with a crack, which relates to the technical field of weld specimen preparation. The method comprises the following steps: S1: Process the bevels at the welding ends of two base metals. The main weld is located between the two bevels, and the two base metals are welded at the main weld; S2: Process a first groove on the outer side wall of the base metal, and the first groove penetrates through the main weld; S3: Weld in the first groove to form an induced layer; S4: Process a second groove on the surface of the induced layer, and perform welding in the second groove by means of fusion welding. After welding, perform a cooling treatment to generate cracks; S5: Complete the welding of the cover layer of the main weld, and cover the crack inside the welding material during welding. By adopting the present invention, the crack morphology is realistic, and the position and depth of the crack are easy to control during the preparation process. It can be detected and verified in ultrasonic testing to ensure the reliability of the simulation test results. Compared with the fatigue loading method, this method effectively saves the production cost and time of cracks.

The invention discloses an electric pulse crack propagation inhibition method for fatigue cracks of an aluminum alloy plate. Preparing an electric pulse applying device (2) and a thermal infrared imager (3); performing electric pulse treatment on the fatigue cracks on the aluminum alloy plate component (1) by adopting an electric pulse applying device; performing real-time temperature monitoring on fatigue cracks on the aluminum alloy plate component by adopting an infrared thermal imager; and the temperature data, monitored in real time, of the fatigue crack is used as feedback data, and parameters for performing electric pulse treatment on the fatigue crack are controlled and adjusted according to the feedback data, so that the peak temperature of the crack tip of the fatigue crack is far lower than the solidus temperature of the aluminum alloy plate component. According to the method for inhibiting crack propagation through the electric pulse, the stress state of the crack tip of the fatigue crack on the aluminum alloy plate component is changed through non-high-temperature electric energy input, and the microstructure passivation of the crack tip is induced, so that the macroscopic propagation rate of the crack in the subsequent fatigue load is effectively reduced, and the purpose of prolonging the service life of the aluminum alloy plate component is achieved.

The application discloses a kind of wind turbine blade life intelligent monitoring method and system, method includes steps: extracting blade low-frequency damage model feature, constructs blade fatigue damage database;High-frequency load analysis model is established, and then based on high-frequency load analysis model, blade load is calculated, and blade fatigue load is obtained;Based on blade fatigue damage database and blade fatigue load, blade fatigue life is obtained, and blade fatigue life is evaluated.The application avoids using complex nonlinear fatigue damage model, while ensuring simulation accuracy, simplifies the order of magnitude of calculation;SCADA data and wind resource data are read online, and the blade load is evaluated in real time by high-frequency load analysis model, which improves the accuracy and timeliness of online monitoring of blade cross-section fatigue load.

The application discloses a kind of concrete asymmetric fatigue test systems based on ultrasonic vibration loading, including universal testing machine, ultrasonic frequency generator, ultrasonic transducer, upper displacement amplifier and lower displacement amplifier and for reducing system loading eccentric moment ball hinge mechanism, the ball hinge mechanism is connected with lower displacement amplifier bottom by clamping connecting disc.This application also provides a kind of concrete asymmetric fatigue test method based on ultrasonic vibration loading, fix the concrete test piece of equal cross section cylinder between upper displacement amplifier and lower displacement amplifier, then open universal testing machine, ultrasonic frequency generator and ultrasonic transducer, realize the ultrasonic vibration asymmetric compression-compression fatigue cycle loading of concrete test piece.The application can realize the asymmetric compression-compression fatigue loading of concrete test piece by ultrasonic fatigue test technology, solve the problem of high time cost in the super-long life fatigue test of traditional concrete fatigue test system.

This invention discloses a system fatigue reliability prediction method for large aerospace planetary mechanisms. The steps are as follows: The fatigue load history of gear teeth under the coupled action of the system's global elastic behavior is calculated using the hierarchical finite element method to obtain load information; the probabilistic fatigue strength curve of the gear teeth is fitted based on gear low-cycle fatigue testing and the minimum order statistic conversion method; the load information and the probabilistic fatigue strength of the gear teeth are input into a reliability prediction model to obtain a system fatigue reliability prediction model that can consider the influence of system structural elements, establishing a mapping path from key structural elements of large aerospace planetary mechanisms to system reliability indicators. This invention leverages the stiffness potential of core structural elements to balance the contradiction between reliability and lightweight requirements in large aerospace planetary equipment; detailed tooth root stress calculations are not required in the system-level model; and a gear tooth probabilistic fatigue strength conversion method is proposed, thereby saving significant simulation and testing costs.

This invention provides a method and apparatus for determining the failure probability of an energy pipeline with axial cracks under fatigue loading. The method includes: determining the rupture failure pressure of the energy pipeline based on current monitoring data; determining the total growth rate of the axial crack based on a first growth rate caused by environmental factors and a second growth rate caused by cyclic fatigue loading; constructing a limit state model for pipeline rupture or leakage based on the rupture failure pressure and the total growth rate of the axial crack; and solving the limit state model using a predefined algorithm to determine the failure probability of the energy pipeline. This method, based on current monitoring data of the energy pipeline and considering the influence of both environmental factors and fatigue loads within the pipeline on crack growth, enables the assessment of the pipeline's failure probability over a future operating period, saving time and economic costs and ensuring the safety of the energy pipeline.