268 results about "Structural fatigue" patented technology

The invention relates to the technical field of structural health monitoring and intelligent diagnosis, in particular to a structural fatigue damage identification method based on acoustic emission and deep learning, and the method comprises the steps: collecting a structural response signal under a fatigue load through an acoustic emission sensor array, inputting the structural response signal to a CNN-BiLSTM-Attention mixed deep learning model, and carrying out the recognition of the structural fatigue damage through the CNN-BiLSTM-Attention mixed deep learning model; the model extracts local time domain features through a dynamic adaptive convolution kernel, captures long time sequence dependence by using a bidirectional long-short-term memory network, focuses key damage features through a bimodal space-time attention mechanism, divides damage stages based on a nonlinear dynamic threshold algorithm of fracture opening amount, constructs a training data set of physical-data fusion, and performs dynamic time domain feature extraction. The learning rate is optimized by adopting a gradient sensitive cosine annealing algorithm, and the robustness of the model is improved in combination with an anti-noise and anti-loss function. The method integrates physical characteristics and an intelligent algorithm, and has the advantages of adaptive noise suppression, strong cross-domain generalization ability, high real-time performance and the like.

The invention discloses a bridge health prediction device based on a Beidou system and a monitoring analysis method, and relates to the field of bridge health monitoring. The method comprises the following steps: S1, deploying monitoring points at key structure nodes of a bridge, and collecting three-dimensional position information and multi-source data by using a Beidou system and a multi-type sensor; s2, constructing a time-varying displacement field and a continuous deformation tensor, fusing stress and strain to construct a structural fatigue factor, and introducing environmental disturbance to realize dynamic correction of the fatigue factor; s3, a health state function is constructed based on the stress response, the displacement gradient and the deformation tensor, a damage mapping function is constructed in combination with accumulated deformation and a historical threshold value, and a damage thermodynamic diagram is generated; and S4, finally fusing fatigue, health and damage indexes to evaluate bridge risks, and performing dynamic early warning. Through fusion of mechanical tensor features and environmental disturbance modeling, a multi-index linkage fatigue and damage assessment mechanism is constructed, and the precision, robustness and global perception ability of bridge health monitoring are improved.

The invention discloses a copper bar connection state detection method and system, particularly relates to the technical field of copper bar state detection, and is used for solving the problem of poor early recognition of copper bar connection deterioration. According to the method, resistance and temperature rise conditions at the joint of the copper bars are measured synchronously in the load change process, signal denoising is realized in combination with finite difference filtering, and characteristic evolution conditions at the joint are captured; the method comprises the steps of determining an analysis window based on a real-time load change event, constructing a thermoelectric track point set and dividing a load rising and falling period, forming a continuous dynamic thermoelectric response curve, dividing a temperature rising track and a temperature falling track through a temperature change trend, extracting a resistance drift amount and a hysteresis loop area, and identifying a connection degradation trend and a structure fatigue characteristic. And connection state information generated by thermal stress action and thermal cycle asymmetry is obtained during load change, and a detection strategy is adjusted according to an analysis result, so that early degradation identification and intelligent risk grading of the copper bar connection state are carried out, and the sensitivity and accuracy of copper bar detection are improved.

The invention relates to the technical field of intelligent operation and maintenance, in particular to a bridge maintenance system based on data analysis, which comprises a multi-source data acquisition module, a fatigue degradation monitoring module, a wave velocity anomaly positioning module, a risk collaborative judgment module and a maintenance task planning module. According to the method, structural fatigue characteristics are subjected to cross validation by integrating two-dimensional data of a strain sequence and a stress wave propagation parameter, and a dynamic window range deviation degree is adopted to replace a static threshold value to establish a datum reference linked with a bridge bearing period; a same-path propagation difference value is extracted by using a high-frequency and low-frequency stress wave frequency band energy separation technology to detect continuous overrun, and a degradation trend weight and a priority list of damage space distribution are generated in combination with multi-index coexistence verification and a hierarchical sorting strategy; resource allocation is optimized by integrating a multi-level response mechanism of emergency repair coordinate positioning, directional detection and regular inspection, accurate crack positioning is achieved, the early degradation trend capturing capacity is enhanced, the misjudgment risk is reduced, and an operation and maintenance response chain is shortened.

The invention relates to a method for detecting surface cracks of a steel rail, which comprises the following steps of: controlling the environmental temperature difference change of the steel rail to enable thermal response to generate a hysteresis phenomenon, inducing slight asynchronous thermal fluctuation with discontinuous and asymmetric thermal diffusion in a local area of a material surface layer, and exposing a potential crack boundary; non-contact low-intensity laser thermal disturbance multi-angle scanning is used for executing a disturbance penetration test, non-structural thermal anomalies are removed, and a real crack area is determined; carrying out attenuation curve recording on the thermal response after multiple rounds of disturbance excitation, and reversely deducing the integrity degree of the microstructure below the crack according to the disturbance settlement time so as to judge the structural fatigue grade; environmental steady state comparison is carried out on the same detection area, through comparison of temperature and humidity, wind speed and radiation environment parameter changes before and after disturbance, if the crack area still continuously shows thermal response abnormity under a constant environment condition, it is confirmed that the thermal characteristic is caused by a structural crack, and otherwise, misjudgment caused by external accidental interference is eliminated.

The invention provides a multi-axial fatigue damage evaluation method and device for a steel bridge welding seam considering welding residual stress, and relates to the technical field of fatigue strength analysis and service life prediction of a steel bridge structure. The method comprises the following steps: measuring three-dimensional residual stress in a geometric transition area of a steel bridge welding seam by adopting X rays, acquiring heat distribution and surface topography data in combination with infrared thermal imaging and structured light scanning, and realizing multi-source data space alignment based on a unified coordinate system; secondly, random disturbance is applied to the residual stress, stress fluctuation in service is simulated, and a robustness weight risk factor is constructed; the method comprises the following steps: constructing a bimodal deep neural network, adaptively fusing information of an infrared thermal imaging image and a welding seam three-dimensional topography image through an attention mechanism, training a fatigue risk regression model by taking a robustness weight risk factor as a supervision signal, completing prediction of risk factors at all positions, dividing low, medium and high risk levels based on a preset threshold value, and obtaining a fatigue risk prediction result. And accurate grading evaluation of the fatigue damage of the welding seam is realized.

The invention provides a bridge structure risk early warning method based on Bayesian decision and information value. According to the method, Bayesian prior analysis is carried out through structure monitoring data, a cost model comprises structure failure cost, maintenance cost and management and control cost, and a structure state model is obtained through structure fatigue reliability analysis. Bayesian prognosis test analysis is carried out in the next step, short-term future monitoring data distribution is predicted based on current monitoring data, then structural fatigue reliability analysis is carried out on the possibility of each kind of monitoring data, corresponding failure risk indexes are calculated, and information values are calculated based on a cost model. And finally, through maximizing the information value, obtaining an optimal structure early warning threshold value under Bayesian prognosis test analysis so as to determine the optimal early warning time. According to the self-adaptive structure risk early warning method, the early warning cost and the structure performance degradation are comprehensively considered, and rapid early warning decisions with safety guarantee and economic benefits can be achieved.

The invention belongs to the technical field of mechanical structure health monitoring and life prediction, and particularly relates to an engineering machinery bearing structure fatigue life intelligent monitoring method, which comprises the steps of 1, building a high-fidelity geometric model, 2, building a finite element model, 3, building a finite element simulation data set, 4, building a neural network agent model, and 5, building a neural network model. 5, working parameters and loading history are obtained; and 6, a visual operation and maintenance platform is integrated. According to the intelligent monitoring method for the fatigue life of the engineering machinery bearing structure, the evolution process of fatigue damage of the structure can be intelligently deduced based on the working parameters and the loading history of the structure, dynamic calculation of the residual life and real-time early warning of the service risk are achieved, calculation resources are saved, the fatigue life evaluation efficiency is improved, and the engineering machinery bearing structure fatigue life monitoring method is suitable for popularization and application. The problems of dependence on off-line simulation, response lag, discontinuous evaluation and the like in traditional structure life management are solved, the intelligent operation and maintenance level of the engineering machinery is effectively improved, and safe and efficient operation of the engineering machinery is guaranteed.

The invention belongs to the technical field of computer simulation, and particularly discloses a method, a system and equipment for predicting the fatigue life of a composite material patching and repairing structure. The prediction method comprises the following steps: establishing a composite laminated plate fatigue damage analysis method in combination with an improved Hashin criterion, finite element analysis, a strength degradation model, a rigidity degradation model and a Camanho material parameter degradation model; fatigue life prediction analysis is carried out on the non-porous laminated plate and the porous laminated plate by using the method; and comparing a prediction result with a test result, and verifying the effectiveness of the established composite material laminated plate fatigue damage analysis method. On the basis, a composite material fatigue damage analysis method and a cohesion unit are combined, and a repair structure fatigue life prediction model is established. The fatigue life prediction method for the repair structure is provided by taking the composite material patching and repairing structure as a research object, and has certain engineering practical significance and better practical value.

The invention relates to the technical field of unmanned aerial vehicle evaluation, in particular to an unmanned aerial vehicle structure fatigue prediction method and system, and the method comprises the steps: obtaining a sensor data set of a key structure part of an unmanned aerial vehicle; dynamically evaluating the data quality of the sensor data set, and dynamically adjusting a data cleaning preprocessing strategy according to an evaluation result; constructing a stress field model reflecting global stress distribution of the structure on the basis of the preprocessed sensor data set in combination with real-time flight environment parameters; and according to the stress field model and material fatigue characteristics, calculating a fatigue damage prediction value of each structural part. The objective of the invention is to improve the prediction precision of the fatigue damage of the unmanned aerial vehicle structure.

The invention relates to the technical field of port cranes and mechanical engineering, in particular to a crane structure fatigue life prediction method and system. The invention provides a crane structure fatigue life prediction method. The crane structure fatigue life prediction method comprises the steps that a finite element model of a crane structure is established, and a stress-load mapping relation matrix of crane structure nodes is generated through dimension reduction processing; collecting actual working data of the crane structure; performing data processing on the actual working data, and constructing an actual working load spectrum; based on the stress-load mapping relation matrix and the actual operation load spectrum, generating a stress-time history used for calculating the fatigue life structure node of the crane; and calculating the fatigue damage of the crane structure and predicting the residual fatigue life by combining a stress-life curve and an accumulative damage theory of a crane structure material. According to the method provided by the invention, online, real-time and accurate prediction and visualization of the fatigue life of all structures of the crane are realized, and a basis is provided for formulating an accurate operation and maintenance plan.

The SPAR type offshore wind turbine fairlead structure fatigue analysis method provided by the invention specifically comprises the following steps: calculating an equivalent effect variable amplitude value of a fatigue dangerous point by adopting a critical plane method to obtain a fatigue damage parameter, and calculating the fatigue damage parameter according to a modified Manson-Conffin formula and a Miner linear cumulative damage theory. The fatigue damage of the fairlead of the offshore wind turbine under different working conditions of ice thickness or ice speed under the combined action of wind-wave and wind-ice is accurately evaluated; by establishing a numerical model of the fairlead and considering the geometric structure and stress characteristics of the fairlead, the fatigue life of the fairlead is accurately calculated, and the fatigue life and fatigue reliability of the fairlead are analyzed. According to the method, the fatigue life of the fairlead of the offshore wind turbine under multiple working conditions is analyzed, the service life of equipment is prolonged, the reliability is improved, and the blank of research on the fatigue influence of ice load parameters on the floating mooring fairlead structure is filled.

The invention provides an energy storage container fireproof heat insulation performance evaluation method comprising the following steps: obtaining battery pack layout, temperature, electrolyte state and pressure change in an energy storage container, and carrying out pretreatment to obtain initial trigger characteristics of battery thermal runaway; acquiring material distribution and structural parameters of the bay firewall in the spraying erosion damage area, and simulating the erosion effect of high-temperature electrolyte spraying on the partition wall through a finite element analysis algorithm to obtain a partition wall damage distribution range; acquiring temperature gradient distribution data of the partition wall in the risk area where the fire breaks through isolation, and calculating thermal stress difference caused by temperature gradient to obtain the accumulation degree of structural fatigue; predicting the remaining service life of the partition wall structure according to the accumulation degree of structural fatigue, and adjusting the material thickness and the layered structure of the partition wall according to the design life requirement; and according to the generation probability of the partition wall cracks, dynamically updating the material ratio and the structure parameters of the partition wall, and generating a final firewall design scheme.

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 relates to a full-self-anchoring flexible connection stainless steel composite steel pipe, and belongs to the technical field of full-self-anchoring steel pipes. A self-adaptive dynamic compensation structure is introduced, and when the extrusion stress borne by a rubber ring exceeds a preset threshold value, the structure is in linkage fit with a spring movable part through a sliding part; the axial displacement compensation and the elastic pre-tightening force are cooperated, and the extrusion stress of the rubber ring is dynamically maintained in a reasonable range, so that the sealing effect can be maintained when the rubber ring deforms due to aging or abrasion, the pressure fluctuation caused by heat energy generated by friction between water flow and a pipe wall and environment temperature change can be coped, and the service life of the pipe is prolonged. By means of the design, the situation that the rubber ring bears extrusion stress exceeding a design value due to the fact that internal pressure is increased is avoided, stress concentration and structural fatigue are reduced, the service life of the rubber ring is prolonged, the maintenance cost and the replacement period of a long-distance buried pipeline are reduced, and the vicious circle problem that the service life of an existing structural rubber ring is shortened is effectively solved.

The invention relates to the technical field of high-voltage line mirror bracket safety testing, and discloses a high-voltage line mirror bracket split type safety link structure testing method and system. According to the method, plugging and bending tests are carried out on a high-voltage line mirror bracket split type link structure through a mechanical arm, and interface pressure and structure deformation image data are collected in real time. And analyzing interface wear and structural fatigue damage characteristics by using a pre-trained wear detection model, and outputting a real-time wear degree evaluation result. And after the test period is finished, integrating the multi-modal data and the evaluation result to generate a three-dimensional visual detection report, positioning a wear concentration position, marking an abnormal wear point and quantifying the structural safety level. According to the invention, the problems of incomplete test and inaccurate evaluation in the prior art are solved, and the product safety and reliability are improved.

The invention belongs to the technical field of fatigue life acceleration test equipment, and particularly relates to an acceleration test device and method for the fatigue life of a rubber corrugated pipe limiting structure, the acceleration test device comprises a base and a heat insulation test box, the bottom end of the heat insulation test box is fixedly connected with the upper surface of the base, and two fixing through holes are formed in the outer wall of one side of the heat insulation test box. The device has multiple environment simulation functions, constructs a composite test environment close to the actual working condition, reflects the influence of different environments on the fatigue life of the limiting structure, improves the representativeness of the fatigue life test result of the rubber corrugated pipe limiting structure, realizes automatic failure judgment through resistance real-time monitoring, does not need manual intervention, and improves the test efficiency. The test convenience is improved, the accuracy of the fatigue life test result of the rubber corrugated pipe limiting structure is further improved, the double-sample synchronous test is realized, the time consumption of the multi-sample test is greatly shortened, and the detection efficiency of the fatigue test is remarkably improved.

The invention discloses an anti-distortion and anti-compression cable for an oil platform. The anti-distortion and anti-compression cable is suitable for signal or power transmission in a high-corrosion, high-humidity and high-mechanical-disturbance environment. The cable comprises a plurality of strands of silver-plated copper stranded wire core bodies, a micro-foaming silica gel anti-fatigue buffer layer is arranged outside the silver-plated copper stranded wire core bodies, a movable sleeve layer structure is sleeved outside the silver-plated copper stranded wire core bodies, the movable sleeve layer is composed of a low-friction coating, a sliding main sleeve layer and a rigid shape limiting shell layer, the core wires are allowed to slide freely and be sleeved and positioned when bent and twisted, and structural fatigue and dislocation are prevented. The cable filling body is composed of a high-density supporting framework and a flame-retardant silica gel rope, and an anti-torsion fiber braid layer, a metal shielding layer and a multifunctional sheath layer of a sandwich structure are arranged outside the cable filling body. The cable has the advantages of torsion resistance, compression resistance, self-adaptive structure, self-healing protection and excellent shielding performance, adapts to extreme platform working conditions, improves the system reliability and prolongs the service life.

The invention relates to a steel structure fatigue crack detection system based on digital twinning, and the system comprises a sensing module which is used for collecting fatigue crack monitoring data of a steel structure in real time; the digital twinning back-end data fusion and management module is used for analyzing and standardizing the fatigue crack monitoring data and constructing a digital twinning model of the steel structure so as to map the entity state of the steel structure and the spatial distribution condition of the fatigue crack; the analysis module is used for detecting the fatigue crack of the steel structure according to the fatigue crack monitoring data, updating a detection result to the digital twinborn model for state synchronization, and performing crack risk early warning; and the visualization module is used for displaying the fatigue crack monitoring data and the detection and early warning result output by the analysis module. Compared with the prior art, real-time detection, trend prediction and multi-level early warning of the fatigue crack of the steel structure are realized through cooperative operation of sensing, fusion, analysis and visualization, and the safety and decision scientificity of the operation and maintenance stage are remarkably improved.

This invention discloses a method for the dynamic evolution of a digital twin model of a rotor system. First, finite element models of each component of the rotor system are established and modified to obtain a modified rotor system simulation model. Second, based on residual stiffness theory, the dynamic evolution curves of the rotor system state with varying operating conditions and service time are analyzed from three aspects: bearing wear, bolt loosening, and structural fatigue. Then, simulation and experimental data generated by the modified rotor system simulation model and the rotor system test bench under different evolution states under varying operating conditions are collected. The correlation of multivariate evolution is analyzed based on a multi-objective optimization algorithm to obtain accurate dynamic evolution curves of the rotor system state. Finally, the obtained accurate dynamic evolution curves of the rotor system state are input into the modified rotor system simulation model to obtain a dynamic evolution digital twin model of the rotor system.

The invention discloses a meteorological risk analysis early warning system based on meteorological data, and relates to the technical field of meteorological perception early warning, the meteorological data and structure operation data of an area where a power transmission tower is located are collected, wind direction abrupt change feature recognition is carried out to obtain a wind direction abrupt change rate V theta, a sand and dust invasion change index Esant is constructed, and the wind direction abrupt change rate V theta is obtained; the method comprises the following steps: performing sand-dust invasion state evaluation on a sand-dust invasion judgment threshold Ethresh, performing sand-dust impact response analysis when the sand-dust invasion judgment threshold Ethresh is evaluated as a sand-dust impact period, constructing an instantaneous shear wind pressure stress sigma sh, further obtaining a foundation erosion response coefficient Rfd in combination with a sand-dust invasion change index Esant, and performing coupling modeling on the instantaneous shear wind pressure stress sigma sh and the foundation erosion response coefficient Rfd to obtain a foundation erosion response coefficient Rfd. And the structural fatigue rate PLfat is obtained to evaluate the structural safety state of the power transmission tower, so that the response sensitivity of the early warning system to high-frequency sand and dust disturbance is improved, and safe and stable operation of power transmission facilities under extreme weather conditions is ensured.

The invention discloses an anti-swing predictive control method for an offshore crane, and belongs to the technical field of ocean engineering equipment control. The problem that in the prior art, due to control lag and an inaccurate model, the load swing restraining effect of an offshore crane is poor is solved. According to the scheme, the method is characterized in that the state of a crane and prediction information of future waves are obtained in real time through a state sensor set and a multi-source environment sensing system; mixing the prediction model to predict a crane system state sequence under different control instructions in a future time domain in a rolling manner; based on the prediction sequence, solving a reference control track aiming at suppressing swing and reducing structural fatigue in upper-layer optimization, and solving and outputting an instant control instruction meeting the constraint of an execution mechanism in lower-layer rapid optimization; meanwhile, system health management is independently executed, and a control mode is dynamically adjusted according to evaluation. The method is mainly used for precise anti-swing control of the offshore crane under the complex sea condition, load swing can be effectively inhibited in advance, and operation precision and equipment safety are improved.

The invention relates to the technical field of steel pipe concrete structure detection, in particular to a method for detecting fatigue damage of a steel pipe concrete correction structure for waste incineration power generation. The ultrasonic detection signals under different primary frequencies are subjected to comparative analysis of signal intervals with different amplitude changes, and the ultrasonic detection signals under different frequencies are subjected to targeted filtering optimization processing based on analysis results, so that the accuracy of damage information judgment under different frequencies is comprehensively evaluated. Accurately screening ultrasonic detection signals in the detection process of the correction structure according to an evaluation result, and obtaining a fatigue damage detection result of the correction structure based on a screening result; the accuracy of fatigue damage information judgment of the correction structure is improved, and the detection performance of the concrete filled steel tube correction structure at different positions is improved.

The invention discloses a derrick rotation supporting mechanism overturning monitoring system with a remote monitoring function, and relates to the technical field of remote monitoring, and the derrick rotation supporting mechanism overturning monitoring system comprises the following steps: acquiring vibration acceleration and bolt pre-tightening force data, and performing spectrum analysis to obtain a resonance coefficient so as to judge a resonance state; and an overturning coefficient is calculated according to the bolt pre-tightening force time sequence change, so that overturning risk prediction and early warning are realized, and safe operation of a mechanism is guaranteed. Resonance risks are monitored in real time through vibration spectrum analysis, bolt pre-tightening force attenuation and structural fatigue are effectively prevented, the active protection capacity of a system is improved, overturning risks are dynamically evaluated based on bolt pre-tightening force time sequence changes, the chain loosening effect is accurately recognized, overturning advanced early warning is achieved, and the safety and reliability of a mechanism under the complex working condition are enhanced.

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

The invention relates to the technical field of equipment performance detection, in particular to a construction equipment performance intelligent detection method based on an AI algorithm. The method comprises the following steps: acquiring operation data of each monitoring point of the tower crane, further respectively acquiring characteristics of each monitoring point in a time period, and forming a sample by the characteristics of each monitoring point in the time period; forming a sample set of a first node of an isolated tree of the isolated forest by a preset number of samples containing the samples at the current moment; obtaining the sparse degree and the unstable degree of one feature of one sample; obtaining the abnormal distinguishing degree of one feature, further obtaining the segmentation possibility of one feature of each sample, then segmenting the sample set to obtain two sub-sample sets, and so on, segmenting the sub-sample sets until the depth of the isolated tree reaches a preset depth; and obtaining the abnormal degree of the structural fatigue at the current moment according to each constructed isolated tree. The performance of the tower crane can be effectively monitored.

The invention relates to the technical field of structure fatigue evaluation, in particular to a pipe truss structure fatigue analysis parameter optimization method and system based on deep learning, and the method comprises the following steps: constructing a deep learning proxy model fusing a multi-scale structure diagram encoder, a working condition parameter encoder and a damage dimension curve decoder; training the model by using a high-fidelity training data set; for the target truss structure and the load working condition, predicting a damage dimension relation curve through the model; determining the optimal dimension of a rain flow counting matrix by analyzing the convergence characteristic of the curve; and predicting a multi-working-condition damage value through a model, and screening out a dominant working condition based on a damage contribution percentage. According to the method, the deep learning agent model is used for replacing traditional iterative simulation, rapid optimization of key parameters in fatigue analysis is achieved, the efficiency and accuracy of fatigue evaluation of the large truss structure are remarkably improved, and the generalization ability of the model is improved by fusing the physical effect of a multi-scale structure chart encoder to capture key hotspots.

The invention provides a fatigue crack propagation life prediction method and system for a mechanical structure, and relates to the technical field of structural fatigue reliability, and the method comprises the steps: solving a stress intensity factor of a crack-containing structure; measuring associated data of the stress intensity factor amplitude delta K and the crack growth rate da / dN under different stress ratios; solving first equivalent crack surface traction force distribution corresponding to the external load and second equivalent crack surface traction force distribution corresponding to the residual stress field; calculating crack propagation effective driving force under variable amplitude load based on a strip yield model; the crack length and the cycle number are updated until the crack expands to the termination length af; calibrating parameters of a fatigue crack growth rate model based on delta KCPD; and superposing the variable-amplitude load spectrum and the equivalent crack surface traction force distribution to the two-dimensional substitute crack body, and generating a fatigue crack propagation life curve of the mechanical structure by a strip yield model. According to the method, quantitative prediction of the fatigue crack propagation life of the mechanical structure is realized, and the method has relatively high solving precision and applicability.

The application provides a ship structure fatigue strength analysis method and system, which calculates the main engine vibration load and the wave load received by the ship structure based on the ship data, the characteristic data of the ship structure and the global sea state data, then calculates the stress response process under the combined action of the wave load and the main engine vibration load, the spectral density function of the stress response process, each order spectral moment of the stress response process and the zero-crossing rate of the stress response process, then calculates the stress response and the stress response peak of the ship structure under the action of the sinusoidal vibration load, calculates the stress cycle number of the ship structure based on the stress response and in combination with the fatigue life S-N curve, further calculates the fatigue damage under the action of the main engine vibration load, and finally calculates the total coupling fatigue damage under the long-term sea state, and further calculates the fatigue damage of the ship structure under the combined action of the high and low frequency loads, which effectively improves the accuracy and reliability of the ship structure fatigue strength calculation.

The invention discloses a cable-beam combined structure 1 / 2 subharmonic resonance vibration reduction method. The method comprises the following steps that S1, the optimal damping force needed by a cable in the current motion state is obtained according to a time-lag vibration reduction rule; s2, calculating a target current required by the MR damper according to the obtained optimal damping force; s3, mapping the target current to a current interval which can be actually applied by the MR damper by using a mapping algorithm to obtain a mapping current; s4, adjusting individual overlarge mapping current to obtain applied current; and S5, current is applied to the MR damper so as to control the cable-beam combined structure. According to the method, the optimal damping force and the target current are accurately calculated, and the time-delay selection rule is combined, so that 1 / 2 subharmonic resonance can be accurately inhibited, the vibration amplitude of the cable-beam composite structure under the specific frequency is effectively reduced, the fatigue damage risk of the structure is reduced, and the service life of the bridge is prolonged.