518 results about "Fatigue loading" patented technology

Techniques and apparatuses for wind turbine component fatigue load measurement and assessment are disclosed. In one embodiment the component is a tower, fore-aft and side-to-side signals from a two-axis accelerometer attached to a bedplate of a wind turbine are used to measure tower fatigue loads. A yaw axis azimuth position signal can also be used for tower fatigue load measurement and assessment.

The invention relates to a material fatigue-life predicting method based on a support vector machine, and discloses a method for predicting the fatigue service life of a structural material, which comprises the steps of: obtaining material fatigue performance data, selecting a proper input and output parameter to construct a training sample set, establishing a fatigue-life predicting model based on the support vector machine, preprocessing a fatigue load, and calculating the fatigue life. The material fatigue-life predicting method has the advantages of realizing the nonlinear accumulation of fatigue damages by using less material fatigue performance data, and improving the accuracy of predicting the life. The method provided by the invention is suitable for the structural material fatigue life estimation and the life prolonging analysis, and has an important theoretical significance and an actual application value in formulating a reasonable maintenance plan for prolonging the service life of the material.

A turbine disc/blade tenon connection high-temperature combined fatigue loading device comprises a low cycle load stress application mechanism, a force transmission pin, a force transmission main tension plate, a force transmission crown plate, a force transmission round bar, a blade clamp, a rolling bearing, a hold-down bolt, a high cycle transmission plate, a high-frequency heating cycle, and a vibration generator, wherein, the low cycle load stress application mechanism is connected with the force transmission main tension plate through the force transmission pin; the force transmission main tension plate is connected with the force transmission round bar through the rolling bearing; the lower end of the force transmission crown plate is sleeved on the force transmission round bar, and the upper end is connected with the load bearing dummy club of the blade clamp through the rolling bearing; the blade clamp is connected with the blade of a turbine through the hold-down bolt; the turbine disc is connected with the low cycle load stress application mechanism through the force transmission pin; the high cycle transmission plate is connected with the blade clamp through the hold-down bolt; and the vibration generator is positioned on one side above a high cycle load transmission plate. The loading method is characterized in that the force application point of low cycle loads is moved backwards, thereby enabling small high cycle loads to be smoothly transferred to the tenon connection position, ensuring the stress distribution along the tenon tooth is reasonable, and preventing combined loads from interfering with each other.

The invention provides an independent pitch control method for a large wind turbine, which comprises a coordinated pitch control process: detecting the rotation speed omega g of a motor, subtracting the reference rotation speed omega ref with the detected rotation speed omega g to obtain the rotation speed deviation delta omega; by the PI control, obtaining a coordinated pitch angle beta c expected to be output by the coordinated pitch control; the method also comprises a deviation pitch control process: 1) detecting the load (Mz1, Mz2 and Mz3) of the root part of a blade and an impeller azimuth signal psi, and making the Park conversion of the load (Mz1, Mz2 and Mz3) of the root part of the blade to obtain load components of Mtitl and Myaw; 2) obtaining the outputs of beta1 and beta2) by being controlled by the PI controller respectively; 3) by the PARK inverse conversion, obtaining the deviation pitch angles (beta1', beta2' and beta3') expected to be output by the deviation pitch control; and 4) obtaining the three blade expecting output pitch angles in the independent pitch control so as to control the action of the servo motor to realize the pitch control. The method can effectively avoid the appearance of the bigger fatigue loads.

A method for the non-linear ultrasonic online detection of early fatigue damage to a metal material belongs to the field of nondestructive detection. The method comprises the following steps: determining an excitation signal parameter according to the thickness of a tested piece and inputting the parameter to an arbitrary function generator to generate a sound signal; determining a threshold value of an acoustic emission instrument according to the amplitude of a no-load noise signal; performing fatigue loading on the tested piece, continuously detecting an acoustic emission signal in real time with an acoustic emission sensor, amplifying the acoustic emission signal, inputting the acoustic emission signal into the acoustic emission instrument, and judging ring with the acoustic emission instrument when the amplitude of the acoustic emission signal exceeds the preset the threshold value of the acoustic emission instrument; detecting a non-linear ultrasonic signal at equal time interval if the acoustic emission instrument does not display the ring or the times of the continuous ring is not more than an empirical value; and stopping detection if the displayed ring times is more than the empirical value, because fatigue cracks are generated and develop. On the basis of non-linear ultrasonic nondestructive detection, the method of the invention introduces acoustic emission technique, so the method does not make incorrect judgment when detecting the early fatigue damage to the metal material and realizes continuous online detection.

The invention relates to a damage calculation method for low-cycle fatigue and high-strength impact coupling based on a local stress strain method. The damage calculation method comprises the following steps of: (1) analyzing a fatigue load spectrum, calculating nominal stress strain of each stage of multiple stages of amplitude-variable fatigue load spectra, and converting the nominal stress strain into local stress strain; (2) calculating fatigue life and damage corresponding to each stage of fatigue load local strain when a product is impacted; (3) calculating the fatigue life and the damage corresponding to each stage of the fatigue load local strain when the product is impacted and the impact is in an influence range, and considering the damage probability in a fatigue circulation unit when the product is impacted; (4) calculating impact performance influenced by fatigue accumulated damage; and (5) calculating comprehensive degree of reliability. Compared with a conventional fatigue damage calculation method, the damage calculation method has the advantages that the influence of high-strength impact on the fatigue damage, the influence of fracture failure caused by direct impact to the life of the product and the influence of the fatigue accumulated damage to the shock resistance of the product are considered, and the fatigue-impact life and the degree of reliability of the product can be well evaluated under a complex environment.

The invention establishes a prediction method for the multi-axial high-cycle fatigue life of a plastic metal material based on a critical plane approach. According to the invention, a fatigue failure mode of the plastic metal material under the condition of combined loading of tension and torsion is taken into consideration, influence of a stress amplitude ratio and phase difference on the multi-axial high-cycle fatigue life under the condition of multi-axial loading is also considered, a fatigue life prediction model for prediction of the multi-axial high-cycle fatigue life is established by using linear combination of a maximum principal stress peak value and a maximum shear stress range on the basis of critical plane criteria of multi-axial fatigue and used for predicating the life of the plastic metal material bearing multi-axial high-cycle fatigue load, and the prediction method for the multi-axial high-cycle fatigue life of the plastic metal material based on the critical plane approach is eventually brought forward. The model established in the invention is based on the critical plane criteria capable of revealing damage of a physical mechanism multi-axial fatigue and takes influence of the stress amplitude ratio and phase difference on multi-axial high-cycle fatigue failure under the condition of multi-axial loading into consideration, and small dispersity and high accuracy of prediction results of the model are realized.

The invention discloses a time-dependent fatigue reliability analysis method based on bilinear cumulative damage. The method includes the steps that 1, the probability distribution type and statistical characteristic parameter of fatigue life data are determined; 2, the appropriate reference life is selected, and a bilinear cumulative damage physical model is built; 3, according to the bilinear cumulative damage physical model, a probability cumulative damage model is built; 4, according to the stress-strength interference theory, a time-dependent fatigue reliability model is built; 5, a reliability curve is drawn and compared with an experimental result; the characteristics of a crack initiation stage and a crack propagation stage in the fatigue failure process and the randomness in the damage accumulation process are comprehensively considered, the bilinear damage theory serves as a modeling base, the probability cumulative damage model is built, through the combination with the stress-strength interference theory, the time-dependent fatigue reliability model based on cumulative damage and critical damage is built, the time-varying characteristics of fatigue loading and the dynamic behavior of the damage accumulation process are reflected, and the reliability prediction in the whole fatigue life cycle is achieved.

The invention belongs to nondestructive testing technology, and relates to a method for manufacturing a surface crack sample for a nondestructive testing sensitivity test. The method adopts a fatigue loading mode to manufacture a crack defect, and the operation is simple; the manufactured fatigue crack defect has small dimensions and belongs to typical crack defect. Therefore, the manufactured fatigue crack defect has excellent representativeness for natural crack defects. The method can successfully acquire crack samples with dimensions of natural cracks; and dimensions and shapes of the samples and directions and positions of the crack defects can meet most test requirements. The manufacturing process is easily controlled, which is particularly applicable to adjustment and experimental verification for circumferential magnetization detection sensitivity in magnetic particle testing, and the method can be applied to testing research of detecting sensitivity of the surface cracks in three nondestructive testing specialities, namely ultrasound, vortex and penetration.

The invention provides a fatigue analysis method and a fatigue analysis device of a structural member in a wind generating set. The method comprises the following steps: establishing a finite element model for a to-be-measured structural member involving bearing connection and related structural members thereof; applying load to the finite element model according to various preset load working conditions respectively; acquiring each node stress result of the to-be-measured structural member under each load working condition through finite element analysis; scaling down the acquired stress results by taking a fatigue load sequence which is pretreated through regularization as a coefficient; synthesizing the stress results under the different load components after scaling down to obtain a stress spectrum of each node of the finite element model of the to-be-measured structural member; calculating a fatigue damage value of the to-be-measured structural member according to the stress spectrum of each node and the stress-life curve of the to-be-measured structural member. By applying the method and the device, the fatigue analysis result of the structural member in the wind generating set is more accurate.

The invention discloses a prediction method of metal material multiaxial high cycle fatigue failure including mean stress effect; the prediction method of metal material multiaxial high cycle fatigue failure including mean stress effect comprises the following steps: using the uniaxial fatigue and the pure torsional fatigue as the boundary conditions for calculating the biggest damage surface born by the material during the fatigue loading process and taking the biggest damage surface as the boundary surface, selecting the positive stress and the shearing stress on the boundary surface as the damage parameter, using the mean stress effect parameter obtained by the uniaxial fatigue for correnting the stress on the boundary surface, and establishing the metal material multiaxial high cycle fatigue failure prediction model including axial direction mean stress and shearing stress influence; the prediction method of metal material multiaxial high cycle fatigue failure including mean stress effect is also applied to the situation without axial mean stress and shearing mean stress. The fatigue service life, the fatigue crack initiation and the initial extension direction of the material under multiaxial high cycle fatigue loading situation can be precisely forecasted while the axial mean stress and shearing mean stress are present.

The invention relates to a method for reducing fatigue loads in the components of a wind turbine subjected to asymmetrical loading of its rotor, comprising the steps of: repeatedly collecting and storing load data of the rotor, determining a load distribution function for the rotor from said stored data, deriving a plurality of periodic functions from said load distribution function, determining actions for the wind turbine control means for reducing the fatigue load of the wind turbine components from said derived plurality of periodic functions, and implementing of said determined actions on the wind turbine control means. The invention also relates to a control system as well as a wind turbine and wind park.

The invention discloses a method for analyzing the fatigue life of a steering knuckle, comprising the following steps: 1) obtaining the fatigue load of the steering knuckle; 2) carrying out uniaxial tensile material test on the use material; 3) if the fatigue load is under the static load condition, the elastic-plastic finite element analysis method is adopted to solve the problem; or, if it is the actual pavement load spectrum, the elastic-plastic finite element analysis is carried out on the points exceeding the yield strength by elastic finite element method and linear superposition method,and the modified stress-strain results are obtained. 4) analyzing the biaxiality of the obtained stress response in time domain to determine the load state of the steering knuckle; 5) calculating thedamage accumulation and life of steering knuckle. The present invention solves the problem of time-consuming finite element solution under the input of actual pavement load spectrum, at the same time, the stress and strain of the material entering the plastic phase are considered, so that the result is more accurate, and fatigue analysis is carried out by combining the static load condition or the single channel static load condition, and more references are provided in the design phase.

The invention belongs to the field of material testing, specifically to a corrosion fatigue test apparatus with high temperature and high pressure circulating water. With the present invention, the problems of the complex structure and the cumbersome use and maintenance in the prior art are solved. The apparatus is provided with a high temperature and high pressure circulating water system, an autoclave and a fatigue machine. The high temperature and high pressure circulating water system is communicated with the autoclave. A test sample is placed in the autoclave, and is connected with a loading part of the fatigue machine. The high temperature and high pressure circulating water system comprises a water storage tank, a circulation pump, a high pressure pump, a buffer tank, a heat exchanger, a preheater, a condenser, a back pressure valve and an ion exchange resin. An inlet of the autoclave is connected with the heat exchanger through a pipeline. The pipeline is provided with the preheater. An outlet of the autoclave is connected with the heat exchanger through the pipeline. The high temperature and high pressure circulating water system is provided for providing high temperatureand high pressure water required by the test. The fatigue machine is provided for performing fatigue loading for the test sample in the autoclave. A control system controls the high temperature and high pressure circulating water system and the fatigue machine.

The invention relates to a material micro-mechanical property biaxial tension-fatigue test system and a test method thereof, and belongs to the field of precise scientific instruments. The test method is characterized in that orthogonal tensile load is applied to a test piece to make two mutually vertical tensions exist in one plane, and fatigue load can also be applied to the test piece on the basis of the tensile load in order to research the micro-mechanical properties of a material under different load forms and load sizes. The system is composed of a precise loading-transmitting unit, a fatigue unit, a mechanics and deformation signal detection unit, and a test piece clamping unit. The test system has the advantages of novel and compact structure, respective realization of uniaxial tension test, biaxial tension test, uniaxial tension-fatigue test and biaxial tension-fatigue test, good compatibility with an optical microscope, and dynamic research of the relationship between the microstructure of the material and the deformation damage mechanism under tension-fatigue load conditions.

The invention discloses a maglev bogie fatigue test loading device, which comprises a testing platform base, a support base, an air spring support, a loading power part used for loading a bogie according to a requirement, and a load transfer device arranged between the loading power part and the bogie, wherein the testing platform base is fixed on the ground; the support base is fixed on the testing platform base; the lower end of the air spring support is pivoted with the support base through a pin roll; the extension direction of the axis of the pin roll is parallel to the front-back direction of the bogie; the upper end of the air spring support is connected with an air spring connecting seat of the bogie; and a horizontal pull rod connecting seat is arranged on the side of the supportbase, and is connected with a side-rolling resistant beam of the bogie through a horizontal pull rod. The maglev bogie fatigue test loading device can well simulate the fatigue load on the bogie, andaccurately test the fatigue property of the bogie.

The invention provides a fatigue analysis method based on magnesium alloy test piece surface temperature characteristics, and belongs to the technical field of magnesium alloy material mechanics properties. The method is characterized in that in terms of uneven stress distribution in a test piece under the fatigue load action of magnesium alloy, surface temperature of the test piece changes due to the elasticoplastic deformation effect, and a relation curve between the surface temperature of the test piece and local stress is obtained; curve shape features are analyzed, so that the stress condition of the test piece under fatigue is determined and the fatigue limit of the magnesium alloy is solved. According to the method, the test piece does not need to be loaded until fatigue failure occurs or loaded by specific cyclic times, the relation between internal stress of the test piece under fatigue and the fatigue limit of the magnesium alloy can be quickly determined through fatigue loading only for 3 minutes, and the method has the advantages of being convenient, fast, accurate and the like.

The invention relates to a test system and a test method for the dynamic bending fatigue property of a small-scale thin film material. The test system comprises an electromagnetic driving part, a sample holding part and a measuring and observing part, and the system provides functions and a test method for dynamic bending fatigue property test for the thin film materials used for various micro/nanoelectronic mechanical systems and supported with matrix or without matrix, the metalized interlinking body foil material used for an integrated circuit and various two-dimensional thin plate type materials and can record in-situ real-time monitoring and analysis to the appearance of the tested sample. The free end of the cantilever beam sample is driven under the electromagnetic force of the electrified coil in the stationary magnetic field to reciprocate relatively to the equilibrium position thereof, thus various types of cyclic fatigue loads can be applied to various material samples, and the precision of the applied fatigue loads can reach the millinewton magnitude. The invention can be used to evaluate the fatigue property and the fatigue crack growth behaviors of various thin film materials.

The invention relates to a tension-compression and fatigue loading testing machine based on a laser confocal microscope, and in particular provides a loading testing machine applicable to a laser confocal microscope platform. The testing machine comprises a fixed base plate, a tension-compression loading device driven by a motor, a fatigue loading device driven by a piezoelectric ceramic, a force sensor, a holding device, a phase-shifting device and the like. The testing machine can perform tension-compression and fatigue loading tests on a typical sample and a film of a metal or non-metal material under macroscopic scale uniaxial stress, and designs the phase-shifting device for an optical testing method for improving the test accuracy and the automation degree. The testing machine has a compact structure, and a test piece is abutted on the lower bottom surface of the testing machine so that the loading under the laser confocal microscope platform can be achieved; besides, the testing machine uses the microscope to collect loading images, and process the images by an optical method to obtain mechanical parameters of a test piece material. The testing machine has the advantages of high system measurement sensitivity, reliable result and wide application range.

The invention provides a wind turbine generator control method, a controller and a control system of wind turbine generator. The method comprises the steps of acquiring the air velocity in front a hub by a distance two to three times the diameter of an impeller, the pitch angle of the impeller at the current moment as well as the rotation angular speed of the generator, calculating the pneumatic torque of the impeller, and calculating corresponding electromagnetic torque; acquiring the current torque given value and a pitch angle given value; and correcting the given value outputted by a torque controller or a variable-pitch controller. The controller comprises a pneumatic torque calculation module, a torque controller, a variable-pitch controller and a controller given value correcting module. The control system comprises a laser radar wind speed measurement instrument, a wind turbine generator, and the above controller. The wind turbine generator control system provided by the invention can respond to the wind speed change in advance to correct the variable-pitch and torque control effect so as to improve the wind energy utilization rate of the wind turbine generator, thereby obviating integral fatigue loads and power generation loss caused by impeller inertia and delay of the pitch-variable system.

The invention relates to a multilevel static-dynamic coupling mechanical loading device for a high-frequency fatigue test, and belongs to the fields of scientific instruments and mechanical property tests of materials. The device comprises a high-frequency fatigue loading unit, a low-frequency fatigue loading unit, a tensile loading and detection unit and a synchronous rotating unit. The device realizes tensile fatigue loading through a servo motor, a piezoelectric stack and an ultrasonic vibrator assembly, and simultaneously realizes detection of load and displacement through a mechanical sensor and an optical fiber displacement sensor. The motor drives a rotating mechanism by a motor to realize real-time dynamic crystal diffraction characterization performed on a sample by a synchronous radiation light source. Moreover, a dual-V gap feature defect sample can realize a composite load test mode of tensile-sheering or tensile-bending and the like close to the actual stress form of a material. The multilevel static-dynamic coupling mechanical loading device provided by the invention is compact in structure, and can integrate multiple test methods, thereby providing an effective test tool for the high-frequency fatigue test of the material.

The invention discloses a high temperature and high pressure corrosion hydrogen permeation kinetic test device and a test method of the device. When the device is used for carrying out fatigue limit measurement, step type fatigue load is applied to material from small to large under the given corrosion condition after hydrogen permeability current is stable; when the hydrogen permeability current is increased along with the increment of the load, the load is proved to cause dislocation movement in the material, so that the load is the fatigue limit of the material in the environment. After the device and the method are adopted, the quantitative relation between a fatigue load state and hydrogen permeation quantity can be measured in situ in an online way in the high pressure hydrogen sulfide corrosion environment, the internal relation between stress and segregation diffusion of hydrogen can be visually expressed, and the characteristics of the mutual relation of multiple data can be established.

The invention discloses a big data combined complex terrain wind electric field design platform and method. The big data combined complex terrain wind electric field design platform comprises a simulation platform, a big data workstation and an optimization layout platform; the simulation platform comprises a meso-scale numerical simulation module, a down-scale wind resource model module, a terrain considered wind field flowing model module and a wake stream model module which are connected successively; the data workstation comprises a wind electric field big data platform and a data analysis model module; and the optimization layout platform comprises a wind electric field generating capacity calculation model module, and a wind electric field optimization layout calculation model module. According to the big data combined complex terrain wind electric field design platform and method disclosed by the invention, a generating capacity model is corrected based on the big data workstation; operation modes and geographical factors which affect fan equipment are embodied in generating capacity calculation to reduce a fatigue loading rate of a fan; and thus, the maintenance cost is reduced, and the fan arrangement is optimized reasonably.