26 results about "Fatigue stress" patented technology

The invention provides a passenger car body fatigue life prediction and early warning method fusing visual and frequency domain data. The method comprises the following steps: synchronously acquiring a car body vibration time domain signal and a road surface image; converting the time domain signal into a power spectral density curve, extracting frequency domain features, and combining image visual features to jointly identify the grade of the road surface; constructing and dynamically calibrating a digital twin simulation model based on the curve; fusing physical, frequency domain, virtual, visual and knowledge data, and predicting the residual fatigue life through a neural network; on the basis of the power spectral density curve, calculating equivalent fatigue stress through a Miller criterion to carry out fatigue evaluation, and calculating maximum quasi-static stress according to a criterion 3 to carry out static strength evaluation; and dynamically triggering and managing monitoring, early warning and emergency three-level closed-loop early warning according to the road grade, the fatigue damage value and the stress intensity ratio. Accurate sensing of working conditions, fatigue-strength collaborative evaluation and multi-stage dynamic early warning are realized, and the accuracy and practicability of passenger car body safety monitoring are improved.

The invention belongs to the field of corrosion fatigue performance, and particularly discloses a milling workpiece corrosion fatigue life prediction model construction method and a process parameter optimization method.The milling workpiece corrosion fatigue life prediction model construction method comprises the steps that a surface quality prediction model is constructed based on process parameters and corresponding workpiece surface states obtained through tests, and the workpiece surface states comprise surface roughness and hardness; introducing a fatigue stress concentration factor and a work hardening ratio into the initial fatigue life model to respectively reflect local stress concentration caused by surface topography and machining surface hardening caused by milling, and performing surface roughness correction and surface hardness correction on the initial fatigue life model; obtaining a fatigue life model related to the surface state of the workpiece and the corresponding corrosion fatigue life; and combining the surface quality prediction model and the fatigue life model to form a corrosion fatigue life prediction model of the milling workpiece. According to the method, corrosion fatigue life prediction and process parameter optimization of the nickel-aluminum bronze milling workpiece can be realized, and important guidance is provided for actual processing.

According to the electromagnetic reversing valve, the structure of the electromagnetic reversing valve is optimally designed, the concave part is additionally arranged on the transition part of the valve body part, and / or the convex part is arranged on the first plate-shaped part of the valve body part, so that stress generated when a high-temperature and high-pressure medium enters the valve body part is dispersed, fatigue stress generated by the valve body in a high-pressure environment is effectively weakened, and the reliability of the electromagnetic reversing valve is improved.

The invention relates to a movable flap (16) for the leading edge of an aircraft wing, the flap being intended to be mounted on a fixed part (8) of the wing and comprising two flap ends (16a, 16b) positioned opposite one another along the span (17) of the flap, the flap defining a leading edge zone from which a lower surface and an upper surface extend, the surfaces being spaced apart from one another over the height (21) of the flap. According to the invention, the flap has a generally upwardly concave shape in its nominal state in order to limit fatigue stresses on the flap during flight.

The application discloses a method and device for testing coating performance of an engine hot-end component, and the method comprises the following steps: obtaining working condition data of an engine, wherein the working condition data comprises task profile data, simulation data and measured data of the engine; establishing a temperature model, a corrosion load model and a fatigue stress model based on the working condition data; determining an environment spectrum of the engine based on the working condition data, the temperature model, the corrosion load model and the fatigue stress model, wherein the environment spectrum comprises a time sequence of multiple working conditions of the engine and corresponding environment test parameters in the multiple working conditions; and testing a coating sample of the engine based on the environment spectrum to obtain a test result of the coating sample. The application establishes a mapping relationship between test environment parameters and actual working conditions, and overcomes the simulation distortion problem caused by using fixed environment parameters for testing in the prior art.

The utility model provides a kind of high mileage all-steel load radial tire tread pattern suitable for full wheel position and tire, the design of the pattern groove of the present application can prevent the pattern groove from clamping stone, and can effectively reduce the damage of groove bottom crack caused by groove bottom fatigue stress;The design of U-shaped groove improves the drainage property while ensuring the self-cleaning performance of the tire;Moreover, the angle of the normal direction of the sidewall of the central pattern groove and the sidewall above the tread is the same, which can also make the stress on both sides of the entire tread pattern more uniform.

The invention discloses an engine hot end component coating performance testing method and device, and the method comprises the steps: obtaining the working condition data of an engine, and the working condition data comprises the mission profile data, simulation data and actual measurement data of the engine; establishing a temperature model, a corrosion load model and a fatigue stress model based on the working condition data; based on the working condition data, the temperature model, the corrosion load model and the fatigue stress model, an environment spectrum of the engine is determined, and the environment spectrum comprises time sequences of multiple working conditions of the engine and environment test parameters corresponding to the multiple working conditions; and testing the coating sample of the engine based on the environment spectrum to obtain a test result of the coating sample. By establishing the mapping relation between the test environment parameters and the actual working conditions, the problem of simulation distortion caused by adopting fixed environment parameters for testing in the prior art is solved.

The invention relates to the technical field of single crystal alloy fatigue life prediction, in particular to a nickel-based single crystal alloy fatigue life prediction method considering second orientation and recrystallization defects. The specific method comprises the following steps: obtaining a plurality of nickel-based single crystal alloys as single crystal alloy samples which have different second orientations and have recrystallization defects partially; establishing a crystal plastic model; acquiring fatigue life and fatigue stress parameters; inputting the fatigue stress parameter into a crystal plastic model to calculate the accumulated plastic shear strain of the dangerous point; 1 / 2 of the product of the cumulative plastic cutting strain and the fatigue load in the crystal plasticity or the cumulative plastic cutting strain is used as a fatigue indication factor; and fitting by taking the fatigue indication factor as a vertical coordinate and the fatigue life as a horizontal coordinate to obtain a fatigue life prediction model. According to the method, the recrystallization defect and the influence of different second orientations are considered, the related fatigue indication factors are introduced to construct the fatigue life prediction model between the fatigue indication factors and the fatigue life, and the accuracy and reliability of the prediction result are improved.

The invention provides a nuclear power plant main loop vibration monitoring method and system based on modal analysis, and the method comprises the steps: extracting main and local modal parameters covering target percentage modal participation quality through modal analysis, dividing a characteristic frequency band according to a dominant modal frequency, corresponding to a vibration parameter limiting value, and obtaining a vibration parameter; meanwhile, in combination with a modal stress and displacement distribution database of the model, a material fatigue life curve and a local stress concentration factor, accurately determining a vibration displacement limit value and a bending moment limit value of each characteristic frequency band, and then segmenting an original vibration signal by adopting a digital signal processing technology; the method comprises the following steps: obtaining an independent analysis frequency band corresponding to a characteristic frequency band, carrying out dynamic threshold filtering statistics, then comparing a frequency-band actually-measured vibration amplitude with a corresponding limit value in real time, triggering a differential early warning strategy, finally calculating a multi-modal actual distribution stress in combination with an actually-measured vibration value and a modal database, and verifying the multi-modal actual distribution stress with a standard fatigue stress. Accurate control of the vibration risk of the main loop piping system and scientific guarantee of structural safety are achieved.

The invention relates to a sling corrosion-multi-axial fatigue life prediction method and device. The prediction method comprises the following steps: S10, acquiring key mechanical parameters of a sling under a predetermined load; s20, establishing a layered slip finite element model of the sling based on a layered slip theory, and solving the fatigue stress amplitude of each layer of steel wire of the sling; s30, the minimum fracture life and the corresponding steel wires are determined, and the accumulated damage degree of the remaining steel wires under the minimum fracture life is evaluated; s40, updating the layered slippage finite element model of the remaining steel wires, and determining the corrosion-multi-axial fatigue life of the sling; and S50, acquiring the corrosion-multi-axial fatigue life of the sling in multiple life cycles, and analyzing the probability distribution characteristics of the corrosion-multi-axial fatigue life of the sling. The performance evolution and failure process of the sling under the coupling action of the corrosion environment and the complex stress state can be simulated, and a reference basis is provided for service state evaluation and maintenance decision making of the sling.

The invention provides a method for predicting the service life of molten parts of a laser shock peening laser powder bed, and relates to the technical field of performance evaluation of additive manufacturing parts. Firstly, based on technological parameters of laser shock peening, residual stress distribution from a material surface layer to a set depth is constructed; based on the strain coordination relation, a relaxation model of residual stress with cyclic loading is established, and equivalent residual stress is calculated through the coupling effect of the external load and the residual stress; then determining a theoretical stress concentration coefficient Kt and a fatigue stress concentration coefficient Kf according to the size, the shape and the position of a defect in the LPBF part; the effective residual stress, the external load, the fatigue stress concentration coefficient and the material fatigue parameter are jointly introduced into a life prediction model, and the fatigue life is calculated; and outputting fatigue life prediction values of the parts under different LSP parameters and load conditions for process selection and structure design.

The invention relates to the technical field of fatigue pressure monitoring, and discloses a non-inductive fatigue pressure dynamic tracking system based on optical fiber sensing, which comprises a flexible optical fiber sensing array, a signal demodulation module, a data processing unit and an output unit, the flexible optical fiber sensing array is used for collecting a dynamic pressure signal of a monitored object under the action of a load and converting the dynamic pressure signal into an optical signal; and the signal demodulation module. Non-inductive monitoring is achieved through the flexible optical fiber sensing array, the flexible substrate adopts a polyimide film and is attached to the surface of a monitored object without obvious protrusions, constraint of a traditional rigid sensor on deformation of the monitored object is avoided, and temperature interference is separated in combination with a temperature compensation optical fiber; and a dynamic correction module adjusts a fatigue damage calculation weight based on a local stress concentration coefficient, so that the problems of hindering of signal transmission and large local fatigue damage evaluation deviation in traditional monitoring are solved, and the requirements of long-term dynamic tracking on a monitoring mode and evaluation precision are met.

The present application belongs to the field of mechanical performance testing, and relates to an intelligent test method for fatigue performance of a wet brake, which collects real-time operation data of the wet brake under a load applied by a loading device during a test process through deployment of a multi-source monitoring array, generates a fatigue stress distribution map representing a stress state of a preset test region of the wet brake based on working condition fusion analysis, and correspondingly identifies a failure warning signal representing a current fatigue damage stage to dynamically adjust parameters of the loading device, analyzes fatigue performance response effects of the wet brake under a current loading strategy during a loading intermittent period of a single test cycle, determines a correction direction of a loading strategy of a secondary test cycle, iteratively optimizes to achieve test convergence, improves consistency of test results and real fatigue damage rules, and improves test efficiency and evaluation accuracy through a closed-loop control and self-adaptive iteration framework to provide a reliable basis for fatigue performance evaluation of the wet brake.

The invention discloses a method, a device, equipment and a medium for evaluating durability of a welding node of an offshore converter station, and the method comprises the steps: synchronously collecting multi-source environment dynamic data of the offshore converter station and vibration data of the welding node, and carrying out the correlation analysis, and obtaining an environment-vibration correlation data set; according to the environment-vibration associated data set and the local plastic deformation data, welding node environment coupling analysis is carried out, and a fatigue stress feature vector is obtained; according to the fatigue stress feature vector, predicting a crack expansion trend to obtain a crack expansion feature vector, and based on the crack expansion feature vector, calculating a comprehensive damage evaluation parameter so as to identify a stress concentration area of the welding node; and according to the crack expansion rate and the stress force data of the stress concentration area, generating a durability evaluation result of each welding node of the offshore converter station. According to the method, the accuracy of durability evaluation of the welding node of the offshore converter station can be improved by dynamically coupling the influence of the marine environment load and fatigue damage evolution on the welding node.

The invention relates to a fatigue stress and service life evaluation method for a long-time service corrosion tubular column, and belongs to the technical field of in-service tubular column structure evaluation.The fatigue stress and service life evaluation method for the long-time service corrosion tubular column comprises the following steps that geometric corrosion morphology data, material performance data and environmental load monitoring data of the service tubular column are collected; according to the method, global stress analysis and local fine stress analysis are performed on a tubular column, the local effective stress amplitude at the corrosion defect is calculated, a dynamically updated S-N curve and a crack propagation model considering the environmental effect are adopted, so that life prediction can be dynamically updated along with corrosion development and load change, the prediction precision is improved, and the prediction efficiency is improved. A probability method is introduced to assess the reliability of the life, a more scientific basis is provided for risk assessment and decision making, finally, a clear safety state level and maintenance suggestion are output, and the method can directly serve integrity management and operation and maintenance decision making of the tubular column.

The utility model discloses an automobile stabilizer bar fatigue testing device, and relates to the field of stabilizer bar fatigue testing. The automobile stabilizer bar fatigue testing device comprises a base, and a plurality of pushing units and a plurality of transmission units are arranged on the base. According to the automobile stabilizer bar fatigue test device, force is applied to the sliding bar through the spring connected with the extrusion seat, fatigue pressure tests under different strengths are carried out by adjusting the deformation degree of the spring and changing the applied force to the sliding bar, upward thrust is applied to one side of the stabilizer bar, and downward tension is applied to the other side of the stabilizer bar; forces in different directions are simulated to be applied to the two sides of the stabilizer bar, fatigue testing is conducted, meanwhile, under the application force of the spring, it is effectively avoided that rigid extrusion is conducted on the stabilizer bar, the stabilizer bar deforms and influences follow-up measurement results, and the situation that the stabilizer bar breaks due to the rigid extrusion is effectively avoided.

The application discloses a kind of based on heat dissipation's ultra-high cycle fatigue stress life curve evaluation method.This method is loaded by stepwise increment fatigue stress amplitude to single sample, until the sample breaks;Real-time monitoring test sample surface temperature rise under different stress amplitude and corresponding cycle loading cycle;By analyzing the heat dissipation of single sample under different stress amplitude, the fatigue life limit under each stress amplitude is calculated, and the complete stress life curve is constructed.The number of fatigue test samples is greatly reduced, the ultra-high cycle fatigue stress life curve of the material is quickly obtained, the experimental cost is effectively reduced, and reliable data support is provided for material design and service safety evaluation.

The invention provides a compilation method for a low-cycle fatigue load spectrum of a volute composite structure of a pumped storage power station, and the method comprises the steps: building a finite element mesh model of a steel volute-concrete composite structure according to engineering design data, and enabling the model to reflect the interaction between a steel volute and concrete; simulating a water filling and pressure maintaining construction process by adopting a hinge unit, and obtaining the stress of the steel volute at each node under a static loading condition; determining a steel volute prototype load history based on the operation mode and the water level real-time monitoring data; editing a load process by adopting a rain flow counting method; compiling a low-cycle fatigue stress spectrum according to the stress and load history of the steel volute; establishing a stress mixing model, and obtaining a temperature influence proportion; and correcting the low-cycle fatigue stress spectrum according to the mixed model. The method fills the blank of load input in the anti-fatigue design of the steel volute, improves the accuracy of stress calculation, and provides a reliable basis for predicting the fatigue life of the volute.

The invention discloses a pipeline creep monitoring method and device, a storage medium and electronic equipment, and the method comprises the steps: collecting parameters, images and temperature data of a to-be-monitored component, enabling the images of the to-be-monitored component to comprise an original image and a creep image, and marking a timestamp for the images of the to-be-monitored component; calculating total strain according to the original image and the creep image, calculating elastic stress according to part of parameters of the to-be-monitored component, calculating fatigue stress according to the temperature and part of the parameters of the to-be-monitored component, and calculating fatigue strain and elastic strain respectively according to the fatigue stress, the elastic stress and the elastic modulus; calculating creep strain according to the total strain, the fatigue strain and the elastic strain; a creep limit value database is set according to equipment operation requirements, the set creep limit value database comprises temperature, operation time and a creep limit value, the creep strain calculated in real time is compared with the corresponding creep limit value, if the creep strain is smaller than the creep limit value, no risk exists, and if the creep strain is larger than the creep limit value, a maintenance alarm is sent.

This invention discloses a fatigue verification method for crane structures. It constructs triggering terms under four stress conditions, merging four allowable fatigue stress formulas into a single combined formula. The original four independent formulas become four sub-terms of the combined formula, and the constructed triggering terms trigger each of these four sub-terms. This allows the combined formula to automatically select the correct formula for verification based on the stress condition of each unit, ensuring the completeness and accuracy of the verification while avoiding unnecessary conservatism. This invention significantly reduces the areas where the structure requires reinforcement or upgrades to the weld construction level, not only reducing structural weight but also saving manufacturing costs and enhancing product competitiveness.

The invention relates to the technical field of fabricated cement concrete pavements, and discloses a lightweight fabricated concrete hollow slab design method and hoisting method.The design method comprises the steps that firstly, structural parameters and input load parameters of a fabricated cement concrete pavement are determined; boundary conditions are determined, pavement structure grids are divided, and a finite element model is established; 2, determining the size of the thinnest reference solid plate through the parameters calculated by the finite element model in combination with a load fatigue stress and temperature fatigue stress calculation formula and a limit state check formula; step 3, taking the thinnest reference solid plate as a precast concrete surface layer, and building a finite element model by using the parameters in the step 1; 4, the hollow rate, the radius of a hollow plate round hole and the height of the center of the round hole serve as variables, and the hollow plate size meeting the limit state requirement and with the maximum hollow rate is screened out. By means of the design method, the problem that in existing hollow slab design, the lightweight effect is insufficient or the bearing performance is poor can be solved.

This invention provides a testing device for fatigue damage and life assessment of rubber liners, relating to the field of rubber component testing technology. It includes: a device housing; a central partition plate is fixedly installed in the upper middle part of the housing; two sets of frame plates are fixedly installed on the rear side of the central partition plate; four sets of fixed roller frames are fixedly installed on the front side of the central partition plate inside the housing; three sets of movable roller frames are slidably installed at the intervals between the four sets of fixed roller frames; and two sets of test rollers are rotatably installed inside each of the fixed and movable roller frames. This invention, through a clamping and positioning structure composed of a triangular guide groove and a positioning electric cylinder, combined with the staggered arrangement of the four sets of fixed roller frames, three sets of movable roller frames, and the built-in test rollers, can apply continuous alternating torsional and bending loads to the rubber liner, simulating the fatigue stress state of the rubber liner during actual service. This solves the deficiency of existing testing devices lacking a realistic damage simulation structure, facilitating subsequent damage detection and life assessment.

This invention relates to the field of engine rotor elastic support technology, and discloses a method, device, equipment, and medium for calculating the radial performance of an integrated elastic support. For the special structure of an integrated elastic support with measurable axial force, this invention establishes a three-segment mechanical model including elastic bar one, elastic ring, and elastic bar two. By calculating the moment of inertia of each section about its own centroidal principal axis, the total deflection of the free end under radial load is obtained using the superposition method, and the radial stiffness is then determined. Simultaneously, based on the bending moment distribution, the fatigue stress at each connection end on elastic bar one and elastic bar two is calculated. This provides a dedicated analytical calculation method for radial stiffness and fatigue stress for this novel elastic support structure, filling the gap in existing technology which is only applicable to single-segment elastic bars, enabling designers to quickly and efficiently obtain the radial stiffness and stress level of the elastic support.

The invention provides a method and system for evaluating air hole defects in a ship welding structure, and the method comprises the steps: obtaining the feature information of the air hole defects in an actual ship welding structure; according to an actual ship welding structure, constructing a three-dimensional welding structure model comprising pore defects; calculating a fatigue stress range of the pore defect; according to the fatigue stress range and the material performance parameters of the ship welding structure, the crack propagation behavior of the pore defect is calculated through a crack propagation model; generating a failure evaluation curve according to the material performance parameters; based on the crack propagation behavior, calculating evaluation parameters under different cycle times; and comparing the evaluation parameters under different cycle times with the failure evaluation curve, and judging the influence of the pore defect on the structural safety in combination with the designed life.

The application discloses a kind of characterization methods of asphalt mixture modulus decay law under three-dimensional stress state, comprising the following steps: preparation asphalt mixture direct tensile, indirect tensile and uniaxial compression test specimen;Asphalt mixture direct tensile, indirect tensile and uniaxial compression strength and fatigue test are carried out;Power function relationship equation of asphalt mixture strength and loading rate is established;Respectively establish the modulus decay equation of asphalt mixture under direct tensile, indirect tensile and uniaxial compression mode;According to the initial equivalent stress of fatigue and the equivalent stress when fatigue failure, fatigue stress intensity ratio is calculated;Establish the characterization model of asphalt mixture modulus decay law under three-dimensional stress state;The application realizes the unified characterization of modulus decay law of asphalt mixture under different loading modes, provides theoretical, method and technical basis for realizing the scientific conversion from material fatigue damage to structure fatigue damage.

The application provides a passenger car body fatigue life prediction and multi-level early warning method combining visual and frequency domain data, which comprises the following steps: synchronously collecting time domain signals of car body vibration and road surface images; converting the time domain signals into power spectral density curves and extracting frequency domain features, and combining the image visual features to jointly identify the road surface grade; constructing and dynamically calibrating a digital twin simulation model based on the curves; combining physical, frequency domain, virtual, visual and knowledge data, and predicting the remaining fatigue life through a neural network; based on the power spectral density curves, calculating the equivalent fatigue stress through the Miller criterion to perform fatigue evaluation, and calculating the maximum quasi-static stress according to the three criterion to perform static strength evaluation; and according to the road surface grade, fatigue damage value and stress intensity ratio, dynamically triggering and managing the monitoring, early warning and emergency three-level closed-loop early warning. The method realizes accurate working condition perception, fatigue-strength collaborative evaluation and multi-level dynamic early warning, and improves the accuracy and practicality of passenger car body safety monitoring.