353 results about "Fatigue loading" patented technology

The invention relates to a multi-machine cooperative yaw control method and device considering a dynamic wind direction and a medium. The multi-machine cooperative yaw control method comprises the steps that S1, the dynamic relation between the wind direction and a wake flow area is established based on a Gaussian-curl hybrid model; s2, constructing a single-machine yaw optimization model based on model predictive control, optimizing single-machine yaw by taking maximum generating capacity of a wind power plant and reduction of fatigue load as optimization objectives, and obtaining a single-machine optimal yaw angle through rolling optimization and feedback correction; and S3, a serial optimization method is adopted to carry out multi-round iterative optimization on one fan by one fan, and an optimal multi-fan cooperative yaw control result is obtained. Compared with the prior art, the method has the advantages that higher total generating capacity and more balanced fatigue load can be realized, so that the whole wind power plant reaches the optimal state of power and load in a large range.

The invention belongs to the technical field of nondestructive testing, and particularly relates to a detection method for quantitatively evaluating fatigue damage in a pipeline through a nonlinear ultrasonic technology. 316 stainless steel and SA335GRP-11 ferrite steel samples are adopted, a welding seam area is formed through V-shaped groove welding, fatigue loading is conducted, and actual pipeline fatigue damage is simulated; for the samples with different fatigue cycles, nonlinear response signals of the samples are obtained; fourier transform is carried out on the obtained signal to obtain an energy spectrum of the signal, and energy changes of the signal on a fundamental frequency band and a second harmonic frequency band are analyzed; and calculating a nonlinear coefficient, and analyzing a change rule of the nonlinear coefficient along with fatigue cycles, so that the evolution process of fatigue damage in the pipeline is evaluated. According to the method, energy is used for replacing the amplitude value, on the basis of the formula principle, integration is used for replacing the amplitude value to improve the intensity of the characterization nonlinear ultrasonic signal, the early stage of damage and the later stage of crack initiation are detected, and reliable guarantee is provided for safe operation of an industrial pipeline system.

An in-situ fretting corrosion fatigue testing machine based on synchrotron radiation diffraction and three-dimensional (3D) imaging includes an axial fatigue loading system, a fretting loading system, and a corrosion environment control system, where the axial fatigue loading system includes a driving device, a load control device, and a load sensing device; the load sensing device is configured to measure an axial force and a normal force in real time; the driving device is configured to drive the load control device, thereby achieving axial displacement of the load control device; the load control device is configured to carry out axial fatigue loading of a specimen; and the fretting loading system includes a fretting wear device. The testing machine achieves real-time 3D imaging characterization of wear spot and crack morphology of a material in a fretting corrosion environment, as well as characterization of a residual stress evolution law.

The invention discloses a fatigue load response analysis method for a non-uniform beam of a ship, and particularly relates to the technical field of fatigue load response analys.The vibration coupling degree between the non-uniform beam and other parts of the ship is judged by obtaining the inherent frequency of the non-uniform beam and the other parts of the ship and calculating the vibration coupling degree coefficient; the method comprises the following steps of: acquiring load time-history data of a non-uniform beam, generating a dynamic load spectrum of the non-uniform beam, effectively capturing real load conditions of a ship under various working conditions, and calculating a fatigue damage coefficient of the non-uniform beam through local stress-strain analysis of the non-uniform beam so as to obtain a dynamic load spectrum of the non-uniform beam. A self-adaptive fatigue damage model is constructed based on the vibration coupling degree coefficient and the fatigue damage coefficient, the fatigue damage value of the non-uniform beam is dynamically corrected, the fatigue damage evolution process of the non-uniform beam under different working conditions is reflected through self-adaptive adjustment, and the dynamic property and accuracy of fatigue damage evaluation are improved.

The invention provides a double-space fatigue electron microscope test system, which is applied to the technical field of material analysis, and comprises an electron microscope module, a fatigue loading module and a vacuum isolation damping module, the vacuum isolation damping module controls two spaces of the electron microscope module and the fatigue loading module to be communicated or independent; the fatigue loading module comprises a hydraulic loading actuator, an electromechanical loading actuator, a loading rod and a fixing clamp, the fixing clamp is used for clamping a to-be-tested sample, and the loading rod is used for stretching or extruding the to-be-tested sample; and the fatigue loading module is driven by the moving mechanism to reciprocate along the X axis to adjust the position of the to-be-tested sample or rotate along the X axis to realize switching of different stations. According to the double-space fatigue electron microscope test system, combined use or independent use of the electron microscope module and the fatigue loading module is realized, and adverse factors such as vibration and pulse generated by the fatigue loading module during electron microscope observation are improved; in-situ compensation is achieved by means of cooperation of loading force and displacement of the fatigue loading module, and the observation effect of the electron microscope is improved.

The invention provides a variable pitch control method and system of a wind generating set and the wind generating set. The variable pitch control method comprises the steps that wind speed data at the wind coming side of an impeller of the wind generating set and at the position away from the impeller by a preset distance in the current control period are determined; determining an estimated pitch angle of the current control period based on the wind speed data of the current control period; comparing the estimated pitch angle of the current control period with the reference pitch angle of the previous control period, and taking the comparison result as the reference pitch angle of the current control period; and on the basis of the reference pitch angle of the current control period, blade pitch variation of the wind generating set is controlled. According to the variable pitch control method of the wind generating set and the wind generating set, the problem that the reduction effect of the fatigue load of the whole machine is poor due to control hysteresis is solved, blade variable pitch can be controlled in advance, and the limit load and the fatigue load of the whole machine are better reduced.

The invention relates to the technical field of wind fields, and discloses a fan decoupling control method for coordinating active power tracking and fatigue load optimization so as to achieve the maximum power control requirement, meet a wind field dispatching instruction, achieve power tracking and restrain fatigue loads. According to the method, on the basis of a model prediction control framework, through decoupling control over the rotating speed and the pitch angle of a wind driven generator rotor, multi-target optimization of wind field reference power tracking and fatigue load suppression of components such as fan blades, a gearbox and a low-speed shaft is achieved.

The invention relates to the technical field of load spectrum analysis, and discloses a gear random fatigue load processing method and system based on a GCM counting method.The method comprises the steps that actual operation load data and actual operation environment data of a gear transmission system are collected, and torque is converted into instantaneous contact stress; dividing into a plurality of discrete cells based on discretization processing; carrying out clustering analysis on all discrete cells; constructing a two-dimensional gear counting matrix; the asymmetric cyclic stress is converted into equivalent symmetric cyclic stress, and the total service life of the gear is determined; comparing the equivalent symmetric cyclic stress with cyclic stress under a raindrop counting method to determine an adjustment coefficient, and determining an early warning threshold value according to the total service life of the gear and the adjustment coefficient; and comparing the total fatigue damage value with an early warning threshold value to determine an early warning grade. According to the method, joint statistics of the stress amplitude, the average stress and the environmental characteristics is achieved, and the defects of a raindrop counting method in the aspects of processing meshing discontinuous loads and lacking environmental adaptability are overcome.

The present invention belongs to the technical field of wind farm active power control and discloses a wind farm frequency modulation power distribution method that takes into account the historical fatigue load of the unit. The method comprises the following steps: collecting the frequency data of the wind farm grid connection point; when the frequency change exceeds the frequency modulation dead zone, calculating the wind farm active power change reference value ΔP farm ; Match the station active power change reference value ΔP in the formed scenario strategy set farm The corresponding optimized active power distribution results of the units. This distribution method is compared with the traditional proportional distribution scheme. While meeting the system frequency response requirements, the present invention improves the problems of sudden increase in fatigue load in wind farms and large differences in fatigue accumulation between units, and verifies the effectiveness of the proposed method.

The invention belongs to the field of material mechanical property testing and strain measurement, and particularly relates to a local strain measurement method and system based on a four-point bending and digital image correlation (DIC) technology, and the method specifically comprises the following steps: cutting to prepare a sample, carrying out surface electrolytic polishing, preparing speckles on the surface of the sample to be tested, and carrying out a four-point bending experiment; speckle images of the lower surface of the sample are collected, displacement correction is conducted in combination with bending deflection calculation, the bending load and the strain of the upper surface of the sample are obtained in real time, the stress-strain relation and local strain distribution of the lower surface of the sample are obtained through calculation, and finally deformation and failure mechanism analysis is conducted in combination with surface deformation and crack morphology. The method provided by the invention combines four-point bending and DIC plane strain measurement technologies, can realize stretching, compression and dynamic fatigue loading on the surface of the sample, is suitable for performance test and failure analysis of tension, compression and fatigue deformation of brittle metal materials such as intermetallic compounds and amorphous materials, and has the characteristics of convenience, rapidness and low cost.

The invention provides a chain ring fatigue damage calculation method and system considering wear conditions, under the conditions of multiple working conditions and multiple wear losses, fatigue load calculation and accumulated damage analysis are carried out on a suspension chain ring, and through time domain simulation, finite element calculation, rain flow counting and S-N curve combination, the fatigue damage of the chain ring is calculated. And a working condition-abrasion loss-fatigue damage database is established. According to the method and the system, accurate evaluation and early warning can be provided for safe service management of the anchor chain or the suspension chain in ship and ocean engineering, and the reliability and the economical efficiency of system operation are greatly improved. All the parts of the device can be independently implemented and can also be modularly combined.

The invention provides a fatigue test method, system and equipment based on texture change of carbon fibers and a medium, and belongs to the technical field of material tests.The method comprises the steps that a carbon fiber composite material is selected as a test sample; applying a fatigue load to the test sample according to a designed test condition, and collecting a surface image of the test sample; the method comprises the following steps of: preprocessing an acquired image, clustering according to the gray level and texture similarity of pixels to obtain a plurality of clustering subareas, and marking different clustering areas by using different colors to complete color mapping; extracting texture feature parameters from the image after color mapping, and performing PCA dimension reduction to obtain key texture feature parameters; and comparing the key texture feature parameters of the image under different test conditions, identifying texture feature changes, and completing fatigue performance evaluation. According to the method, image processing and texture feature analysis are combined, so that non-destructive testing of the CFRP fatigue performance is realized, and the testing accuracy and efficiency are improved.

The invention relates to the technical field of metal fatigue life prediction, in particular to an additive manufacturing metal multi-axis high-cycle fatigue life prediction method based on defect characteristics. The method comprises the following steps: performing defect detection on a metal sample to obtain size parameters and position parameters of defects in the metal sample; determining the type of the defect in the metal sample and setting a first correction factor and a second correction factor; calculating the equivalent stress strength factor amplitude of the metal sample under multi-axial loading; acquiring a long crack propagation threshold value of the metal sample; normalizing the position parameters to obtain normalized position parameters; and establishing a fatigue life prediction model of the metal sample according to the normalized position parameters, the equivalent stress strength factor amplitude of the metal sample under multi-axial loading and the long crack propagation threshold value of the metal sample, and calculating the multi-axial high-cycle fatigue life of the metal sample. According to the method, the fatigue life of the metal material containing the additive manufacturing defects under multi-axis high-cycle fatigue loading can be accurately predicted.

The invention belongs to the technical field of impact fatigue performance detection, and particularly relates to a Hopkinson rod three-point bending sample-based constant-amplitude impact fatigue device, which comprises a dynamic indentation system, an energy absorption system, a strain measurement system and a pressure data acquisition system, and is characterized in that the dynamic indentation system comprises kinetic energy application equipment, an impact rod, an incident rod and a three-point bending test bed; the strain measurement system comprises a strain gauge and a dynamic strain acquisition instrument which are electrically connected, the pressure data acquisition system comprises a force transducer and a data acquisition instrument which are electrically connected, and the energy absorption system comprises a flange, a sleeve and a mass block. The device depends on the Hopkinson rod technology, the momentum well design is ingeniously fused, the problem of secondary loading is effectively avoided, constant-amplitude impact fatigue loading is achieved, key parameters such as the yield point, the elastic limit and the breaking strength of the material are accurately measured, and the reliability and safety of the material are comprehensively evaluated.

The invention relates to a non-probabilistic fatigue reliability analysis method for a controllable-pitch propeller hub mechanism under data driving, which comprises the following steps of: considering multiple uncertain sources such as elastic modulus and friction coefficient, modeling each part of the controllable-pitch propeller hub mechanism through parameterization to obtain a finite element model under different uncertain variable values; drawing a fatigue load spectrum by using a finite element simulation load result, and performing fatigue simulation by combining an S-N curve to obtain the fatigue life of each part; and obtaining a non-probability interval model of the fatigue life of each part by using a data-driven agent model and a Monte Carlo method under a limited fatigue life sample condition, and calculating the fatigue reliability of each part by using a non-probability area method. A data driving method is adopted, so that the problems of high cost and time consumption of obtaining enough data in actual engineering are avoided; fatigue reliability analysis is carried out by adopting a non-probabilistic method, so that uncertainty in engineering can be better dealt with, and the fatigue reliability of the controllable-pitch propeller hub mechanism can be more comprehensively evaluated.

The invention provides a test device and a test method for loading a three-dimensional conical fatigue load. The device comprises a bearing beam frame assembly, a sliding rod supporting assembly, a displacement coordination loading system, an axial force loading system, a stay cable simulation test piece and a stay cable simulation fixing tool, by analyzing the working states of flexible connecting structural members such as inhaul cables and mooring ropes, the invention provides a new fatigue loading form, and the loaded axial force is always in the axial direction of the structural members and can rotate in the space; the loading form can truly reflect the'pull-pull 'fatigue life of the structural member in a specific working environment, and is used for guiding maintenance and repair of key equipment.

The invention relates to the technical field of corrosion tests, and particularly provides a corrosion fatigue coupling test device and a corrosion fatigue coupling test method for a buried pipeline. Corrosion and fatigue coupling effects suffered by the buried pipeline are simulated through the circulating pressurizing system, the fatigue loading system and the corrosion environment adjusting system, and related data of the pipeline and soil in the corrosion process are recorded through the data collecting and monitoring system. According to the invention, the test process is closer to the real service environment of the buried water supply pipeline, the temperature, humidity, pH and other parameters in the test box can be kept relatively stable, and the influence of dead load of buildings, vehicles, vibration and other live loads in the pipeline operation process is fully considered, so that the test result is more reliable and accurate, and the test efficiency is improved. Meanwhile, all the systems are controlled in a centralized mode through the controller, so that the experiment period is relatively short, the automation degree is high, operation is easy and convenient, functions are comprehensive, and the application prospect is wide.

The invention discloses a neural network-based turbine blade high-low cycle composite fatigue reliability analysis method, which comprises the following steps of: obtaining a small amount of data samples of a turbine blade through finite element analysis, extracting the characteristics of the data samples by using a convolutional neural network, and inputting the extracted characteristics into a BP neural network optimized by an improved seagull optimization algorithm to obtain the high-low cycle composite fatigue reliability of the turbine blade. The method comprises the following steps: establishing a CNN-MSOA-BP neural network model of a turbine blade under a high-low cycle composite fatigue load, taking multi-source uncertainty such as a load parameter and a material parameter into consideration, sampling a large number of input samples through Monte Carlo, and obtaining a corresponding output response through the established CNN-MSOA-BP neural network model, thereby performing reliability analysis of the turbine blade. According to the method provided by the invention, the reliability of the turbine structure under complex loads such as high-low cycle compound fatigue can be analyzed, the method has relatively high precision and operation efficiency, and theoretical support is provided for reliability analysis and optimization of turbine blades.

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 discloses a wind power plant active yaw optimization method and system considering a fatigue load of a wind turbine, and relates to the technical field of wind turbine power generation, and the method comprises the steps: obtaining a wake flow model for calculating the equivalent inflow wind speed of a wind wheel surface of the wind turbine; determining a wind wheel surface equivalent inflow wind speed-yaw angle-thrust coefficient two-dimensional lookup table and a wind wheel surface equivalent inflow wind speed-yaw angle-power two-dimensional lookup table of each wind turbine in the wind power plant; constructing an equivalent fatigue load proxy model of the wind turbine based on a blade aerodynamic load and blade gravity coupling effect; and constructing an optimized objective function by taking power maximization and equivalent fatigue load minimization as objectives, solving the optimized objective function through an optimization algorithm according to the actually measured wind turbine-wind measurement data, the wake flow model, each two-dimensional query table and the equivalent fatigue load proxy model, and determining a target yaw angle combination. On the basis of the scheme, the fatigue load caused by the wake effect is reduced while the power improvement is guaranteed, and the active yaw optimization reliability is improved on the whole.

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 provides a wind power blade girder layering damage failure analysis method based on body-shell coupling. The method comprises the steps that a full-size blade geometric model and a full-size blade shell finite element analysis model are established; selecting a full-size blade from a blade root pitch circle to a 1 / 3 blade length section as a shell analysis model; embedding the prefabricated layered defect into the full-size blade girder area by adopting a body-shell coupling method to obtain a body-shell coupling model for blade girder damage failure analysis; blade root fixing constraint is adopted, equivalent fatigue load is applied to the end of the shell analysis model through a multi-point constraint method, out-of-plane displacement of the center point of the upper surface of a sub-plate and the center point of the lower surface of the sub-plate is extracted, and a layered expansion failure process along with load action time is extracted; and carrying out layering failure research on the layering damage of the full-size blade. The method can solve the problem that there is no effective analysis method for the main beam layering failure mode and the expansion path of the wind power blade.

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

The invention discloses an offshore foundation platform for relieving tendon fatigue load of a tension leg and an adjusting method. An offshore foundation platform for relieving tendon fatigue loads of tension legs comprises a platform body, a tension leg system and a driver. The platform body is provided with a cavity and floats on the sea surface; the tension leg system comprises a plurality of tension legs and a suction barrel, one end of each tension leg is connected with the platform body, and the suction barrel is arranged on the seabed and connected with the other end of each tension leg; the driver is provided with a water inlet and a water outlet, the driver is a water pump, the water inlet of the water pump is immersed below the liquid level of the seawater, the water outlet of the water pump is communicated with the cavity, and the driver is used for pumping the seawater into the cavity or pumping the seawater out of the cavity. The stability and safety of the platform can be improved, the fatigue load of the tendons of the tension legs can be relieved, and the service life of the tendons of the tension legs can be prolonged under the excitation of a complex marine environment.

The invention discloses a vibration and conventional fatigue load coupled nonlinear damage accumulation prediction method. The method comprises the following steps: analyzing and determining a peak stress at a dangerous point under the loading of a conventional fatigue load according to a finite element model of an engineering component; determining a stress amplitude probability density function at the dangerous point under random vibration loading according to structural dynamics analysis; searching a pre-generated material fatigue life curve; determining equivalent stress at the dangerous point under random vibration loading according to the fatigue life curve; calculating the ratio of the peak stress loaded by the conventional fatigue load at the dangerous point to the random vibration equivalent stress, and establishing a coupling damage parameter according to the vibration and conventional fatigue load coupling series; and establishing a nonlinear damage accumulation model of vibration and conventional fatigue load coupling. According to the nonlinear damage accumulation model provided by the invention, the influence of vibration, a conventional load sequence and a coupling series is considered, the parameter determination is simple, and high-precision prediction of structural damage evolution under complex load coupling can be realized.

The invention relates to the technical field of gearbox fatigue analysis, in particular to a gearbox fatigue analysis method and system. The method comprises the following steps: monitoring vibration data of a gearbox of a wind driven generator through a vibration sensor, firstly extracting an abnormal vibration state and carrying out frequency domain structure analysis to obtain abnormal vibration frequency domain structure data; then, based on the frequency domain data, fractional frequency multiplication sudden change intensity analysis is carried out, side frequency band sudden change intensity data are obtained, and the fatigue load of the gearbox is simulated and quantified through the data; then, feature learning is carried out by utilizing fatigue load data, and a gearbox fatigue analysis model is constructed based on a decision tree algorithm; and finally, sending the model to a terminal so as to execute the fatigue analysis method. According to the method, the gearbox fatigue analysis technology is optimized, so that the gearbox fatigue analysis technology is more perfect.

The invention provides a self-adaptive double-entropy-multi-scale Transform unsupervised cross-domain composite material damage prediction method, which comprises the following steps: preprocessing an acoustic emission signal and extracting a double-entropy feature matrix based on the acoustic emission signal acquired by a composite material test piece under a tensile-tensile fatigue load; constructing a data set based on the double-entropy feature matrix and training a damage evolution model; and inputting the double-entropy feature matrix corresponding to an acoustic emission signal into the trained damage evolution model based on the acoustic emission signal acquired by the composite material test piece under the shear fatigue load, so as to realize real-time prediction of the shear fatigue damage. According to the method, the cross-load high-reliability prediction is realized, the feature dimension redundancy is improved, the physical interpretability is improved, the supervision marking cost is reduced, and a brand new solution is provided for engineering application.

The invention discloses a method for evaluating a fatigue weak area of a welded joint based on crystal plasticity, which aims at the problem of fatigue failure of the welded joint caused by complex microstructures such as grain orientation difference and uneven grain size distribution, establishes a quantitative correlation model of grain orientation and size evolution through CPFEM, and combines a macro-micro cross-scale analysis method to evaluate the fatigue weak area of the welded joint. And precise prediction of local stress concentration and crack initiation behaviors of the welding joint under a real fatigue load working condition is realized, so that scientific evaluation of a fatigue weak region is completed. According to the method, an innovative framework of fatigue weak area evaluation is constructed through load working condition reduction and grain characteristic multi-scale coupling, so that excessive simplification of a traditional method on real load conditions is made up, the limitation that a traditional model is difficult to couple a microstructure and a real load is overcome, and the fatigue weakening quantization precision is remarkably improved; and a high-precision analysis technology is provided for anti-fatigue design, process optimization and service life evaluation of the engineering welding structure.

The invention discloses a method for constructing an accelerated life test load spectrum of an integral dropper, which comprises the following steps of: respectively constructing a vibration fatigue load spectrum and a pulse alternating current load spectrum according to simulated fatigue load and current data of the integral dropper, and constructing an accelerated life test load spectrum of the integral dropper after the vibration fatigue load spectrum and the pulse alternating current load spectrum are completed. Performing superposition loading by combining the two, deducing a test loading spectrum of the integral dropper according to a Miner damage principle and an electroplastic effect mechanism, and constructing a fatigue-alternating current impact superposition test loading spectrum; according to the construction method, the action mechanisms of current and mechanical stress are effectively combined on the basis of real working conditions, the working state of the dropper can be reflected more accurately, the actual failure mode of the dropper is better met, the constructed fatigue-alternating current impact superimposed loading spectrum can reflect the stress superimposed effect of the dropper in a complex environment, and the application range of the dropper is widened. By more comprehensively simulating the multi-working-condition environment of the dropper, the reliability of the test result is further improved.

The invention discloses a rapid identification method and a monitoring system for a fatigue damage stage of an asphalt mixture. The identification method comprises the following steps: acquiring an acoustic emission signal generated by a test piece in a fatigue loading process and DIC image data of surface deformation of the asphalt mixture test piece; drawing a curve chart of acoustic emission accumulated impact number and energy changing along with loading times; performing graying processing on the DIC image data, and preliminarily judging spatio-temporal information of the crack; fitting an acoustic emission parameter curve; based on the impact number in the window and the change of acoustic emission energy, the asphalt mixture fatigue damage stage is divided; and aligning the time of the acoustic emission signal with the time of the crack space-time information, and determining the fatigue instability precursor information of the asphalt mixture and the instability failure initial position of the corresponding test piece according to the acoustic emission parameter characteristics before the instability failure of the test piece. According to the method, the acoustic emission signal impact number, energy and DIC image data are combined, and the instability damage of the asphalt mixture is predicted according to the acoustic emission parameter characteristics before fatigue instability of the asphalt mixture.