268 results about "Equivalent stress" patented technology

The invention provides a twin power station collision visual simulation method and system based on physical simulation, and relates to the technical field of data processing, and the method comprises the steps: obtaining a three-dimensional geometric model of a twin power station, carrying out space division, extracting geometric parameters, obtaining material data, constructing a material correlation model and a mechanical model, and carrying out fusion to obtain a physical simulation model; acquiring initial collision condition parameters as boundary conditions, performing local grid encryption, constructing a nonlinear kinetic equation of a collision process, performing time domain solution, determining equivalent stress distribution and equivalent plastic strain distribution, and generating a collision result; judging whether plastic deformation or fracture failure occurs, generating full collision process physical field data, generating a collision animation frame sequence, generating a stress distribution cloud picture and a plastic strain cloud picture, constructing a fracture special effect, and comprehensively generating a collision visual scene.

The invention discloses a cable-stayed bridge tension and compression support service life evaluation method and system under random traffic flow load, and belongs to the field of bridge engineering and structure health monitoring, and the method comprises the steps: carrying out the statistical analysis of traffic load data, building a random traffic flow load model, and generating a load spectrum; correcting stay cable force and modal frequency based on bridge monitoring data, and constructing a refined multi-scale finite element model; a unit fatigue vehicle load is applied to the model, a stress influence line is obtained, a rain flow counting method is adopted to calculate stress amplitude, cycle index and average stress, the stress amplitude, the cycle index and the average stress are converted into daily average equivalent stress amplitude and equivalent daily cycle index through a fatigue damage equivalence principle, and the fatigue life of the tension-compression support is evaluated by utilizing a Miner criterion. According to the method, the problem that the influence of three-way alternating stress on bolt fatigue damage cannot be accurately reflected in the prior art is solved, the service life prediction precision of the cable-stayed bridge tension and compression support is improved, the damage of the tension and compression support can be early warned in advance, and data support is provided for safe operation and maintenance of the cable-stayed bridge.

The invention discloses a complex part molded line optimization design method based on multi-field node feature weighted aggregation. Comprising the following steps: firstly, performing finite element batch simulation according to a geometric design variable, a temperature and a contact surface friction coefficient of a to-be-optimized complex part molded line to obtain a training data set; then, constructing a depth map sampling aggregation neural network fusing space and temperature attention, then training the depth map sampling aggregation neural network fusing space and temperature attention by using the training data set, and obtaining a stress prediction model after training is completed; and finally, in combination with the stress prediction model, performing iterative optimization by taking minimization of the maximum equivalent stress of the complex part as an optimization target, and obtaining the optimal geometric parameters of the molded line of the current complex part in the target temperature interval. According to the method, rapid reconstruction of the stress distribution state of the complex part is achieved, the optimization speed is increased, meanwhile, the precision of an optimization result is fully guaranteed, and meanwhile calculation resources are greatly saved.

The invention relates to the field of mechanical fatigue simulation, and discloses a method for simulating and deducing the number of torsion cycles. Comprising the steps that a component three-dimensional parameterized model is constructed, and material fatigue characteristics are defined; applying a periodic torsion load spectrum containing a harmonic component; adopting a stress influence coefficient matrix method to execute quasi-static finite element analysis, and extracting a multi-axis stress state; calculating the maximum alternating shear stress and the average shear stress based on a critical plane recognition technology; converting into a single-axis equivalent stress amplitude through a gradient enhanced multi-axis correction rule; calculating node fatigue damage by combining an S-N curve and a damage accumulation theory; and when the damage reaches a threshold value, outputting a failure cycle number and a position. The innovation points are as follows: the prediction error is controlled within 10% by a critical plane and multi-axis correction technology; a stress matrix method realizes ten thousand times of cycle-level efficient simulation, and the efficiency is improved by 10 times; the risk early warning accuracy rate is improved to 96% by integrating a process correlation defect model; and the research and development period is shortened by 40% through a life cloud picture and an automatic optimization closed loop. The method is suitable for transmission shaft system reliability design.

The invention provides an aero-engine blade high-cycle fatigue limit prediction method, which comprises the following steps: firstly, performing parameter measurement based on an impact-corrosion coupling damaged blade, calculating to obtain a fractal dimension and a stress concentration coefficient, and correcting equivalent stress by using the fractal dimension and the stress concentration coefficient to obtain a corrected critical distance model; and utilizing the corrected critical distance model to predict and calculate the fatigue limit of the coupling damaged blade. According to the blade high-cycle fatigue limit prediction method provided by the invention, the three-dimensional fractal dimension, the theoretical stress concentration coefficient and the stress gradient distribution function near the root of the notch are creatively integrated into the same model, and the blade fatigue limit obtained through prediction and calculation is highly consistent with the measured value of the test.

The invention discloses a soil-rock composite formation hob fracture avoidance method based on FEM-DEM coupling, and relates to the technical field of tunnel and underground engineering, and the method comprises the steps: building a hob cutting model based on a finite element-discrete element coupling method; generating a soil rock calibration parameter according with the input of the hob cutting model; calculating a cutting force curve of hob impact under any working condition by using the hob cutting model, and extracting the maximum value of the cutting force curve as a load peak value; extracting a cutter ring stress peak value corresponding to the moment of the load peak value; and calculating the current comprehensive equivalent stress of the hobbing cutter ring based on the limit stress, comparing the comprehensive equivalent stress with the dynamically matched yield strength threshold, and judging the risk level of the hobbing cutter ring. According to the method, refined simulation of the whole rock breaking process of the hobbing cutter in the soil-rock composite stratum is achieved, the transient impact load peak value and the induced cutter ring limit stress distribution are captured, and the fracture risk identification precision is remarkably improved.

The invention discloses a cargo floor structural strength design optimization method and system based on load prediction, and belongs to the technical field of freight vehicle structural design. The maximum equivalent stress of each node in a floor grid area is calculated and normalized by constructing a load prediction model of the dynamic distribution state of cargoes in a cargo tank; forming a stress intensity coefficient matrix; identifying a high-risk area and constructing a reinforced target area set; obtaining an initial parameter of the bottom plate structure, establishing a finite element model, and setting an adjustable structure parameter in the target area; a candidate structure design scheme set is generated, simulation calculation is executed, the total structure mass, the maximum stress value and the first-order inherent frequency of each scheme are extracted, and a performance evaluation vector is formed; selecting an optimal design scheme through a multi-objective optimization algorithm, and outputting structural parameters of the optimal design scheme as a final design result; according to the method, the structural optimization design of the cargo tank bottom plate under the complex load working condition is achieved, and the method has high engineering adaptability and practical value.

The invention discloses a petroleum pipeline service life prediction system based on a 3D technology, and relates to the technical field of pipeline service life detection, and the system comprises a contour reconstruction module S11 which is used for obtaining the surface three-dimensional point cloud image data of a petroleum pipeline housing in an actual operation environment, and carrying out the surface contour reconstruction processing based on the three-dimensional point cloud image data, extracting space geometric structure data containing a local deformation defect area; the force-heat coupling analysis module S12 is used for constructing a finite element analysis grid according to the space geometric structure data and loading operation condition data into corresponding grid nodes to generate a force-heat coupling stress field, and the operation condition data comprises a periodic internal working pressure value, along-line temperature field data and an axial disturbance stress tensor; the feature extraction module S13 is used for calculating an equivalent stress distribution value of a defect area node based on a force-heat coupling stress field; according to the invention, accurate quantification of fatigue damage evolution of the defect area is realized.

The invention discloses an MEMS composite film stress gradient measuring device and method. The measuring device comprises a V-shaped thermal actuator structure, a displacement measuring structure connected with the V-shaped thermal actuator structure and a multi-layer cantilever beam structure. The method comprises the steps that a V-shaped thermal actuator structure is used for pushing a displacement measurement structure to move towards a multi-layer cantilever beam structure, and when a contact electrode of the displacement measurement structure makes contact with a to-be-measured beam of the multi-layer cantilever beam structure, a horizontal displacement value s is obtained through reading of the displacement measurement structure; calculating the equivalent stress gradient of the composite film according to the geometric dimension of the measuring device, the horizontal displacement value s and the Young modulus of each layer of film; the MEMS composite film stress gradient measuring device and method have the advantages of being easy to operate, low in cost and high in measuring speed, and can be used for parameter monitoring of a process line.

The invention discloses a method and system for analyzing the rolling resistance of a concrete-filled steel tube combined pier column, and the method comprises the steps: applying an axial compression load to the concrete-filled steel tube combined pier column, and dividing the cross section of the concrete-filled steel tube combined pier column into three layers of regions along a radial material change part; according to corresponding total cross-section average axial strain generated by the steel pipe concrete combined pier column when different axial compression loads are applied, equivalent stress corresponding to each layer of area is calculated, total axial force corresponding to each total cross-section average axial strain is calculated, and a total cross-section average axial strain-total axial force curve is formed; searching a first total cross-section average axial strain corresponding to the maximum value of the total axial force in the total cross-section average axial strain-total axial force curve and a second total cross-section average axial strain corresponding to a first obvious inflection point of the total cross-section average axial strain-total axial force curve, and calculating a ductility coefficient, and judging whether the concrete-filled steel tube composite pier column meets the ductility design requirement or not.

The invention discloses a turbine disc baffle structure optimization method and device, equipment, a medium and a product and relates to the field of turbine rotors, and the method comprises the steps that actual structure information of a turbine disc-baffle rotor system is obtained; performing finite element modeling on the actual structure information to obtain a finite element model; transient thermal analysis and transient stress analysis are sequentially carried out according to the finite element model, and the most dangerous time step where the maximum equivalent stress and the maximum contact stress are located is obtained; establishing a response surface model based on a Kriging model according to the most dangerous time step where the maximum equivalent stress and the maximum contact stress are located and actual structure information; according to the response surface model, a multi-target genetic algorithm is used for optimization, and optimized turbine disc baffle structure information is obtained. Stress concentration is effectively reduced, and the fatigue life is prolonged.

The embodiment of the invention provides a rotor fatigue loss online detection method and device based on a full convolutional neural network. The method comprises the following steps: constructing a turbine rotor geometric model; determining a temperature monitoring point in the rotor geometric model through a finite element analysis tool; performing stress prediction according to the temperature parameters of the temperature monitoring points through a pre-constructed rotor stress field reconstruction model, and generating a rotor equivalent stress; the method comprises the following steps: generating rotor fatigue loss according to rotor equivalent stress through a pre-constructed online calculation model of the fatigue loss of the steam turbine rotor, and directly predicting stress distribution of the rotor according to temperature results of a small number of measuring points in a peak shaving process of the rotor through a rotor stress field reconstruction model of a deep full convolutional neural network. According to the method, high-precision and high-efficiency stress prediction can be provided for the steam turbine under different peak regulation working conditions, so that the fatigue loss of the rotor is accurately detected in real time, and safe operation of the steam turbine is guaranteed.

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 gear pair life prediction method based on dynamic stress, belongs to the technical field of reliability design of mechanical transmission systems, and aims to solve the problem of inaccurate life prediction caused by neglecting a dynamic effect and a real surface topography in an existing gear design method. The method comprises the following steps: firstly, acquiring gear pair interface mechanical property parameters considering shafting vibration, dynamic load and surface roughness, wherein the parameters comprise transient oil film pressure, friction coefficient, oil film thickness and shear stress; solving a three-dimensional subsurface stress field by adopting an algorithm and calculating von Mises equivalent stress distribution; stress volume integration is conducted on different rough surfaces, the honed surface is used as the reference, the relative fatigue life of other surfaces is calculated based on the Zaretsky life prediction theory, and accurate prediction and process optimization of the contact fatigue life are achieved; meanwhile, the dynamic bending stress of the tooth root is calculated based on the dynamic normal load, and the bending fatigue safety coefficient is checked.

The present invention relates to the technical field of mechanical property testing of metal materials, and in particular to a testing method for obtaining material fracture properties based on 0.5T-CT specimen reconstitution technology. The testing method for obtaining material fracture properties based on 0.5T-CT specimen reconstitution technology comprises: preparing an original 0.5T-CT specimen of a base material, and carrying out a fracture property test to obtain a residual 0.5T-CT specimen after the test; testing and analyzing the base material to obtain a full-range equivalent stress-strain relation curve of the base material; determining the range of materials that can be used for preparing a reconstituted specimen; welding a reusable material and an auxiliary material for specimen reconstitution to obtain a reconstituted 0.5T-CT specimen; testing and analyzing a weld material to obtain a stress-strain relation curve of the weld material; determining fracture parameters of the reconstituted 0.5T-CT specimen; and on the basis of the fracture parameters, carrying out a fracture toughness test of the reconstituted 0.5T-CT specimen to obtain fracture properties of the base material and / or the weld material. The testing method in the present invention is simple, and the testing result is accurate.

The invention relates to the technical field of engineering simulation analysis, and provides an ANSYS APDL language-based perforated aluminum plate simulation method, which comprises the following steps of: configuring material attributes and unit types of perforated aluminum plates; defining and parameterizing structure geometric information; a non-perforated edge width and an effective hole arrangement area are constructed from the starting position of the lower left corner of the perforated aluminum plate, and a hole pattern is automatically copied in combination with Boolean operation and circulation logic; grid division is carried out according to grid quality, boundary constraint conditions are set, and a surface load parameter is called to apply a load; and setting a nonlinear solving environment, extracting von Mises equivalent stress and a total displacement value under the action of a load, and performing post-processing to obtain a stress distribution diagram and a deformation calculation result diagram. A set of highly parameterized modeling method is constructed through an APDL of ANSYS, the method has the technical advantages of being clear in operation process and reasonable in configuration logic, and through structural definition and calling of key geometric parameters such as hole graphs, sizes and intervals, the efficiency and accuracy of perforated aluminum plate modeling are improved.

The invention relates to the technical field of gas pipeline detection, and discloses a buried natural gas pipeline integrity digital intelligent detection method and system. The method comprises the steps that pipeline data are collected through a sensing unit deployed in a pipeline, and the pipeline data comprise pipeline stress, pipeline internal pressure and foundation settlement; taking the pipeline data as input, and utilizing a preset machine learning model to predict an equivalent stress predicted value of the pipeline; when new pipeline data is collected, incremental updating is conducted on the machine learning model, a composite loss function is adopted for training in incremental updating, and the composite loss function comprises a mean square error loss item used for measuring a prediction error and a physical constraint penalty item; the physical constraint penalty term applies penalty when the equivalent stress predicted value exceeds the allowable stress of the pipeline material; and generating a safety assessment result of the pipeline according to a comparison result of the equivalent stress predicted value and a preset allowable stress of the pipeline material.

The invention discloses a fatigue damage assessment method, system and equipment for a dangerous part of a blade and a medium, and relates to the technical field of fatigue life assessment of a blade structure.The method comprises the steps that firstly, a coupling correction coefficient obtained based on equivalent stress amplitude is introduced to improve the nonlinear cumulative damage Miner theory; errors caused by insufficient description of the load sequence effect by a traditional linear means are reduced, so that a nonlinear cumulative damage model capable of representing a nonlinear relation between the load sequence effect and cumulative damage is established; then applying a unit equivalent stress amplitude boundary field to obtain an equivalent stress amplitude field, and simulating scalar damage evolution during circulation in a load mode based on isotropic continuous damage mechanics, so that nonlinear effects of thermal-mechanical coupling, stress gradient change and microstructure evolution of the blade are realized; and the coefficients are corrected through sequence coupling, equivalent reflection is carried out in combination with the equivalent stress amplitude or the equivalent stress amplitude field, and the precision of predicting and evaluating the fatigue damage of the dangerous part of the blade is improved.

The invention discloses a reaction steam turbine through-flow method and system based on variable reaction degree optimization, and belongs to the technical field of steam turbine through-flow design. The method comprises the steps that an initial geometric model of a steam turbine through-flow part and thermal boundary conditions of all stages are obtained; inputting the initial geometric model and the thermal boundary conditions into a flow field solver, and solving a flow control equation to obtain an original flow field solution; constructing a functional taking through-flow efficiency as a target, and deducing an adjoint equation corresponding to the flow control equation; solving the adjoint equation to obtain gradient information of the target functional to each level of reaction degree; inputting the gradient information into a sequential quadratic programming optimizer, and iteratively updating the reactance of each stage by combining the maximum equivalent stress upper limit of the moving blade and the lower limit of the through-flow throat area to generate a variable reactance distribution scheme; and adjusting molded line geometric parameters of each stage of stationary blade and moving blade, and outputting optimized three-dimensional molded line data and a digital model file for numerical control machining. According to the method, the in-stage flow loss is reduced, and the design robustness is enhanced.

The invention discloses a vortex-induced fatigue analysis method and device for a deep-sea steel catenary riser, electronic equipment and a storage medium, and belongs to the technical field of ocean facilities. The method comprises the following steps: acquiring motion data of an offshore platform; determining an equivalent oscillatory flow of the offshore platform based on the motion data; according to the equivalent oscillatory flow, vortex-induced vibration response of the deep-sea steel catenary riser is determined based on fluid-structure interaction effect analysis; according to the vortex-induced vibration response, the equivalent stress time history of the deep-sea steel catenary riser is obtained through calculation, and therefore a vortex-induced fatigue analysis result is determined. According to the invention, the platform motion can induce the riser to generate vortex-induced vibration, the equivalent mode is established to convert the platform motion into the oscillatory flow, and the fluid-solid coupling effect between the riser and the flow field is considered, so that the calculation is easy to realize and the precision is high; the perfection degree and reliability of the vortex-induced fatigue analysis result of the deep-sea steel catenary riser can be improved, and the fatigue damage degree of the deep-sea steel catenary riser can be accurately mastered.

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 discloses a non-Gaussian fatigue analysis method considering average stress correction, and relates to the technical field of fatigue damage assessment, and the method comprises the following steps: S1, calculating an equivalent stress amplitude based on an average stress correction model; s2, introducing the equivalent stress amplitude into a non-Gaussian TB method, and establishing a non-Gaussian fatigue damage assessment method considering average stress correction; and S3, carrying out comprehensive evaluation through numerical value verification and applicability analysis. According to the non-Gaussian fatigue analysis method considering the average stress correction, a non-Gaussian spectrum method considering the average stress correction is constructed based on a non-Gaussian TB method and a typical average stress correction model, and the applicability of the method under various conditions is verified; therefore, the problem that the average stress effect cannot be considered when non-Gaussian fatigue damage estimation is carried out in the frequency domain is solved, and efficient and reliable technical support is provided for complex non-Gaussian fatigue damage estimation and life prediction.

The invention discloses a damage evolution prediction method and device based on dynamic order reduction, equipment, a medium and a product, and relates to the field of aero-engine health management and monitoring. The method comprises the following steps: performing a finite element fatigue / creep-fatigue simulation test on a similar structural member covering stress states under various operating conditions, and extracting a time-physical field matrix of finite element fatigue simulation results under the various operating conditions; performing dynamic order reduction processing on the time-physical field matrix to reduce the dimension of the matrix to obtain an order-reduced matrix; constructing a reduced order model; performing equivalent stress field distribution reduction according to the reduced-order model to obtain a reduced-order reduced physical field; and performing damage distribution evolution and fatigue life prediction under fatigue or creep-fatigue load based on the reduced-order reduction physical field, and performing correction based on a fatigue life prediction model. According to the invention, the efficiency and universality of life prediction can be improved.

The invention discloses an additive manufacturing part residual stress optimization method, and relates to the technical field of stress optimization, and the method comprises the steps: checking the exposure energy fraction and volume expansion coefficient of a material as input parameters of a stress BP genetic optimization algorithm; the influence degree of different process parameters on stress is analyzed through analogue simulation, and equivalent stress is output; and designing a stress BP genetic optimization algorithm, establishing an anonymous function constraint prediction range of the analog input parameter and the output parameter, and outputting a corresponding process parameter combination. According to the method, the problem that a process adjustment method depends on experience in traditional stress optimization is solved, automatic optimization of process parameters is achieved, and the efficiency and precision of the optimization process are greatly improved.

The invention relates to a multi-axial fatigue life prediction method and electronic equipment, and the method comprises the steps: obtaining multi-axial fatigue experiment data of a to-be-predicted material, including material performance data and a load spectrum; decomposing the load spectrum to obtain a plurality of half cycles of reaction material loading conditions; calculating normal stress and shear stress on each slope based on the load spectrum data, and calculating fatigue life and damage corresponding to each semi-cycle based on an equivalent stress model; on the basis of an equivalent damage theory, carrying out weighting processing on an inclined plane included angle corresponding to a maximum shear stress surface, calculating a critical plane where fatigue damage occurs, calculating equivalent stress of each semi-cycle, and carrying out fatigue life prediction on the critical plane based on the equivalent stress. Compared with the prior art, the method has the advantages that the accuracy of calculating the critical surface and predicting the fatigue life is improved, the operation is simple, and the implementation cost is low.

The invention discloses a full-life power design method for a steel-concrete composite beam bridge under the action of an automobile load, and relates to the technical field of bridge life evaluation. The method comprises the following steps: establishing a bridge finite element model according to a design drawing, simulating a random traffic flow, performing nonlinear time-history analysis by taking a contact position of a midspan section web and a lower flange plate as a stress attention part, selecting equivalent stress amplitude and a stress cycle index as random vectors, determining a probability density distribution function, selecting an initial point set, and reforming the point set. And determining a bridge fatigue damage performance function, solving to obtain a time-varying probability density function considering uncertainty, calculating reliability, and obtaining a bridge reliability curve graph under the automobile load according to the reliability under continuous time. By establishing a bridge finite element model, bridge nonlinear dynamic time history analysis under the consideration of vehicle action uncertainty is carried out, the structural reliability of a bridge along with the change of the service life under the action of an automobile load can be quickly and accurately calculated, and the service life prediction of the bridge is realized.

The invention discloses a high-frequency fatigue resistant high-speed railway fastener elastic strip design method and system, and the method comprises the steps: building a parameterized model of an elastic strip according to the basic linear parameters of the fastener elastic strip and the parameterized equation of each central axis segment; taking the spatial geometric linear parameters of the elastic strip as design variables, establishing geometric constraint conditions and physical constraint conditions, and constructing an optimized objective function fusing the fundamental frequency and the static equivalent stress of the elastic strip; and according to the established constraint condition and the optimization objective function, performing multi-objective multi-parameter collaborative optimization high-frequency fatigue resistant elastic strip optimization design by using a particle swarm optimization algorithm with the constraint condition to obtain an optimal design variable result. According to the method, the contradiction between high self-frequency and low stress is solved by optimizing the spatial geometric linear parameters of the elastic strip, and scientific reference is provided for prolonging the service life of a high-speed railway fastener system.

The invention provides a carburized ethylene cracking furnace tube residual life prediction method based on small punched hole outer surface sampling. The method comprises the following steps: sampling the outer surface of an in-service ethylene cracking furnace tube by using a small punched hole sampling machine; performing a small-punching high-temperature creep test on the sample; carrying out equivalent stress conversion based on a creep test result; establishing an outer surface residual life prediction equation; calculating furnace tube stress and substituting the furnace tube stress into the prediction equation to obtain outer surface residual life; performing carburization-creep finite element simulation on the furnace tube of the ethylene cracking furnace; obtaining a furnace tube damage distribution condition of a finite element test result; and the overall residual life prediction is completed through the outer surface residual life and the damage distribution relationship. According to the method, furnace tube interruption or production halt is avoided, time and cost are saved, residual life prediction is carried out based on actual sampling and finite element data analysis, and the method has high reliability and accuracy and is used for early warning and maintenance decision making in advance, prolonging the service life of equipment and avoiding resource waste and accidents.

The invention discloses a wind turbine blade root bolt group loosening degree online monitoring and fatigue life prediction method, which belongs to the field of wind power, and comprises the following steps: determining the blade shimmy direction of a monitoring unit; arranging strain gauges; acquiring strain data; setting early warning and alarm rules; establishing a monitoring bolt group K value curve; detecting the most unfavorable bolt axial force; calculating the average axial force of the most unfavorable bolt; calculating the tension increment in the screw under the action of the most unfavorable fatigue load on the bolt; the equivalent stress amplitude and the average stress of the most unfavorable bolt are calculated; and determining the residual fatigue life of the most unfavorable bolt. According to the method, the bolt loosening area and the most unfavorable bolt fatigue life prediction in the area are combined, the accuracy of blade root bolt life prediction is improved, and the blade root bolt loosening problem can be found and treated early and the possibility of fatigue fracture can be eradicated through accurate identification of the local bolt group loosening degree.

The invention provides a high-temperature fatigue life prediction method based on EIFS, and relates to the technical field of reliability design. The method comprises the following steps: acquiring first test data for performing a crack propagation test and a high-cycle fatigue test on a smooth component, and second test data for performing a test on a notched component; according to the first test data and the second test data, the equivalent initial defect size of the smooth component and the equivalent initial defect size of the notched component are determined; according to the second test data, the equivalent stress strength factor difference value and the fatigue crack propagation rate of the notched component under the high-temperature condition are obtained; fitting a function relationship among the fatigue crack propagation rate, the equivalent stress strength factor difference value and the crack size to obtain a crack propagation function; and based on the crack propagation function and the equivalent initial defect size and the limit crack size of the notched component, the predicted fatigue life of the notched component under the high-temperature condition is determined. According to the invention, accurate high-temperature fatigue life prediction can be realized.