685 results about "Fatigue cracking" patented technology

The invention relates to the technical field of bridge engineering, in particular to a system and method for predicting the service life of a steel structure bridge after fatigue crack repair. The method comprises the steps that load data and stress data in the operation process of a bridge structure after fatigue crack repairing are collected; dynamic response characteristic parameters are extracted in combination with stress distribution characteristics of the fatigue crack repair area; performing multi-dimensional data fusion and preprocessing on the dynamic response characteristic parameters, and constructing a data set for training a deep learning algorithm; combining a deep learning algorithm and a fracture mechanics theory to construct a crack propagation rate prediction model and a residual life prediction model; according to the operation state of the bridge and the performance degradation law of the repairing area, the remaining life of the repaired structure is predicted, and multi-stage early warning is conducted. According to the method provided by the invention, bridge structure performance evaluation, life prediction and potential risk early warning can be realized, and the safety and reliability of bridge operation are ensured.

The invention relates to the technical field of machine vision structure health monitoring, and discloses a steel structure weld fatigue cracking real-time monitoring system based on machine vision. The system comprises a space-time registration and fusion module, a multi-scale feature analysis module, a health monitoring module, a crack deduction calculation module and a regulation and control strategy generation module. Performing space-time registration and pixel-level fusion through the visual data of the plurality of image sensors to generate a synchronous multi-source image stream; a multi-level welding seam characteristic spectrum is constructed through multi-scale characteristic analysis, and a welding seam structure knowledge base is dynamically updated; the knowledge base and the real-time characteristic spectrum are used for monitoring the welding seam health state, and abnormity is recognized; deducing a crack initiation position and an evolution path in combination with historical damage data; and real-time load information is fused to pre-estimate the remaining service life, and a structural integrity regulation and control strategy is generated online. According to the invention, high-precision fusion of the multi-source visual data and active prediction of the crack trend are realized, and the monitoring accuracy and the early warning capability are improved.

The invention belongs to the technical field of computer-aided manufacturing, and relates to a method and system for predicting the propagation rate of fatigue cracks across welding zones in electric arc additive remanufacturing, and the method comprises the following steps: S1, manufacturing a sample; s2, performing in-situ SEM fatigue test on the sample; s3, obtaining a corresponding relation between the crack growth rate and the stress intensity factor range of the sample; s4, fitting to obtain a fatigue crack propagation rate model of the sample; s5, establishing a CZH sample fatigue crack growth rate prediction model; and S6, predicting the fatigue crack propagation rate of the sample across the welding zone. The system further comprises an electric hydraulic fatigue test system, a data acquisition module, a database, a fitting module and a prediction module. According to the method, by using the correction coefficient, the fatigue crack growth rate is predicted by using the fatigue crack growth rate parameter of the matrix material area.

The invention belongs to the technical field of metal part surface modification, and relates to a composite strengthening method for a carburized surface of a high-bearing gear of an aero-engine. According to the method, high-hardness and high-density ceramic shots are adopted as media for high-energy mechanical shot peening strengthening, the advantage that the subsurface strain hardening effect of the contact strengthening technology is good and the barb-shaped distribution characteristic of mechanical shot peening residual compressive stress are utilized, extremely high residual compressive stress is introduced to the subsurface position, and the contact fatigue performance of the tooth surface of the gear is improved. High-frequency laser shot peening strengthening is used for secondary treatment, so that the surface layer of the material is subjected to plastic deformation, high-amplitude residual compressive stress is introduced into the surface layer of the material within the depth range of more than 500 microns by utilizing the advantage of large influence depth of laser-induced shock waves, and the residual compressive stress can inhibit fatigue crack initiation, has a certain depth and inhibits fatigue crack propagation; and the bending fatigue resistance of the root of the gear can be effectively improved. And an abrasive flow process is adopted, so that the roughness is reduced to be more than 0.4 mu m.

The invention discloses a method and device for predicting the fatigue life of a high-temperature alloy vacuum electron beam welding structure, and belongs to the technical field of aero-engines. The method comprises the following steps: acquiring fatigue experiment data of a target high-temperature alloy standard sample; extracting the maximum area of an initial defect, a defect shape factor and crack source position information; obtaining a stress intensity factor range considering defect morphological characteristics and a fatigue crack propagation threshold value of a material structure containing initial defects, and correcting a damage tolerance theoretical formula to obtain simulation data; fatigue test data and simulation data are fused to form an initial data set, a fatigue limit is calculated and expanded to the data set, the expanded data set serves as input, training is conducted through a support vector regression method, hyper-parameters are determined through Bayesian optimization, and a fatigue life prediction result of the high-temperature alloy vacuum electron beam welding structure is output. The method provided by the invention can well consider the influence of different morphology defects on the fatigue performance of the welded joint.

The invention discloses an elevator steel wire rope wear real-time monitoring system and equipment thereof, and relates to the technical field of safety monitoring, the elevator steel wire rope wear real-time monitoring system comprises an acquisition and extraction module which acquires real-time surface image data and vibration signal data of a steel wire rope through a sensor array, extracts surface damage features and vibration spectrum features by adopting an image processing algorithm, and sends the surface damage features and the vibration spectrum features to a server; fusing kernel function selection and hyperplane separation to process the preliminary wear feature set; the crack identification module is used for fusing tensile strength and corrosion resistance data in the material characteristic database according to the initial wear characteristic set, classifying potential fatigue crack types through support vector identification and crack morphological characteristics by adopting a support vector machine algorithm, and determining a fatigue crack distribution diagram; according to the elevator steel wire rope abrasion real-time monitoring system and equipment thereof, accurate abrasion evaluation and dynamic maintenance optimization are achieved, the safety of the steel wire rope is improved, and the service life of the steel wire rope is prolonged.

The invention relates to the technical field of aero-engines, in particular to a weak-rigidity welding casing blade bending deformation control method which mainly comprises the following steps: firstly, setting the steps of performing electron beam welding on a blade, an inner casing and an outer casing: positioned welding, penetration welding and modification welding; then setting the electron beam welding sequence of strip welding seams between the blade and the inner casing as well as between the blade and the outer casing as the third welding seam, the fourth welding seam, the first welding seam and the second welding seam; and finally, the electron beam welding step in the first step is executed on the four welding seams according to the electron beam welding sequence determined in the second step. According to the mechanism of generation of welding buckling deformation, the welding buckling deformation of the blade is compensated by setting the steps of weak-rigidity cartridge receiver blade electron beam welding and setting the welding sequence, the straightness of the cartridge receiver blade is controlled, meanwhile, the influence on stress concentration parts such as a blade body anti-icing groove hole is reduced, the probability of fatigue cracks is reduced, and the service life of the cartridge receiver blade is prolonged. Therefore, the service life of the engine case is prolonged.

The invention discloses an active learning and physical loss-based fatigue crack growth rate prediction method, which comprises the following steps of: splicing and fusing a preprocessed stress intensity factor, a stress ratio, pre-strain and stress amplitude, and taking the fused characteristics as the input of a model; embedding the Jones model into a loss function of the neural network, constructing a physical information time sequence model based on the Jones model, setting a parameter set, selecting a most valuable training sample from a training set by using active learning, retraining the model by using the selected most valuable training sample, selecting an optimal model, and evaluating the optimal model by using a test set; fusing the actually measured stress intensity factor, stress ratio, pre-strain and stress amplitude of the to-be-predicted material, and inputting into the obtained prediction model to obtain a predicted value of the fatigue crack growth rate. By adopting the technical scheme of the invention, the fatigue crack growth rate of the material in the whole life period can be efficiently and accurately predicted at low cost.

The invention relates to a fatigue crack prefabricating method suitable for a TiA1 alloy CT sample, which comprises the following steps of: sequentially generating non-penetrable fatigue cracks with certain lengths on two side surfaces of the CT sample through asymmetric loading under sine cyclic load by utilizing the crack propagation resistance characteristic under plane stress, and then generating a middle crack through symmetric loading, so as to prefabricate the fatigue cracks on the two side surfaces of the CT sample. And connecting the non-penetrable cracks on the two sides to form penetrable fatigue cracks, and expanding the cracks to the required length. Compared with a traditional method for directly prefabricating the penetrable fatigue crack, the method is easy to operate, high in success rate and high in efficiency, the fatigue crack with the needed length can be rapidly and accurately prefabricated, and the defect that when a TiA1 alloy CT sample uses a traditional fatigue crack prefabricating method, due to the fact that force is too large, the TiA1 alloy CT sample is suddenly unstable and fractured is overcome; or cracks cannot be generated for a long time due to too small force.

The invention discloses a metal fatigue crack initiation simulation method for coupling holes and microstructures, which comprises the following steps of: firstly, establishing a microscopic scale model by collecting microstructure characteristic data and hole distribution data in a metal material, obtaining basic parameters by combining a mechanical property test result, and deducing and calculating microscopic orthotropic parameters; the method comprises the following steps of: scanning internal defects of an alloy, establishing a hole defect model with the same characteristic information according to the scanned internal defects of the alloy, extracting key holes through finite element simulation to establish a geometric model, introducing a stress concentration coefficient, and replacing a shear stress amplitude calculation mode in a Tanaka-Mura dislocation theoretical formula with a stress amplitude calculation mode. And micro-scale numerical simulation of fatigue crack initiation of the metal material with the hole defect is completed. According to the method, factors such as the microstructure and the internal holes of the material are considered, and the finite element simulation technology is combined, so that accurate prediction of the microscale metal fatigue crack initiation life can be realized.

The invention belongs to the technical field of aircraft strength experiments, and particularly relates to a hybrid-driven metal multi-fatigue crack propagation fusion prediction method. The method comprises the following steps: establishing a stress intensity factor expression under multiple fatigue cracks; initial distribution of material parameters in the Paris physical model is obtained, and posterior distribution of the material parameters is adjusted; based on the stress intensity factor expression under the multi-fatigue crack and the posterior distribution of the material parameters, obtaining an improved Paris physical model for describing the multi-fatigue crack propagation process; a depth encoder network model is established, and a network bottleneck layer is utilized to extract guided wave deep features with strong correlation with the fatigue crack length; establishing a guided wave data driven multi-fatigue crack length online monitoring model; and building a particle filter fusion framework, and correcting and improving a distribution interval of uncertain material parameters in the Paris physical model according to guided wave monitoring data to realize dynamic tracking and prediction of metal multi-fatigue crack propagation.

The invention relates to the technical field of railway track engineering, in particular to a heavy haul railway steel rail optimization method, device, equipment, medium and product, and the method comprises the following steps: determining a stress concentration area of a heavy haul railway based on a fatigue crack distribution position and dynamic observation data on the surface of a steel rail of the heavy haul railway; curve fitting processing is conducted on the steel rail profile of the stress concentration area, and fitting profile control parameters of the fitted steel rail profile are obtained; inputting the fitting molded surface control parameters and the wheel parameters of the truck into a pre-constructed vehicle-track multi-body dynamic model to obtain multiple pieces of special molded surface data, and obtaining fatigue crack initiation life corresponding to the special molded surface data based on the special molded surface data; and on the basis of the fatigue crack initiation life, screening molded surface data meeting a preset requirement from the special molded surface data to obtain target molded surface data, and determining the steel rail molded surface corresponding to the target molded surface data as a target steel rail molded surface. The determined target steel rail profile can prolong the service life of the steel rail.

The invention discloses a method and device for testing the fatigue crack growth rate of a metal material based on temperature gradient change, and relates to the technical field of metal material detection. Mounting a constant low-temperature component and a constant high-temperature component close to two ends of the sample respectively; pasting a plurality of thermocouples on the middle surface of the sample; a magnetic powder dynamic moving assembly is installed on the surface of the sample, and a constant-temperature state is given to magnetic powder; loading a bidirectional tension-compression fatigue testing machine along the through hole of the sample; a thermal imager is arranged far away from the parallel sample, and a thermal imaging image is shot; according to the data, the fatigue crack growth rate of the sample at the corresponding temperature is obtained; according to the method, the fatigue crack growth rate of the metal material can be rapidly tested, meanwhile, the temperature gradient is formed in the sample, the influence of the temperature on the crack growth rate can be obtained in different temperature areas, the device required by the whole test is simple in structure, low in cost and convenient to load and disassemble, and the whole efficiency of the test is effectively improved.

The invention relates to precipitation-hardening stainless steel and a preparation method and application thereof. The stainless steel comprises the following chemical components: 0.05%-0.25% of C, 0-0.15% of Si, 0.2%-0.5% of Mn, 9%-18% of Cr, 0.2%-5% of Ni, 0.5%-5% of Mo, 0-0.5% of V, 5%-13% of Co and the balance of Fe and inevitable impurities. During preparation, alloy raw materials are forged or rolled after being smelted and cast, or prepared into spherical alloy powder through an atomization method / rotating electrode method and then subjected to 3D printing, a formed component is prepared, and then the product is obtained through aftertreatment. By controlling the proportion of alloy elements and cooperating with an optimized post-treatment process, the dispersion degree and strengthening effect of second-phase precipitation are improved, impact toughness is improved, 3D printing cracking is avoided, excellent comprehensive mechanical properties, especially high-temperature strength, are obtained, the fatigue cracking risk is reduced, the service life is prolonged, and the production cost is reduced. And the corrosion resistance of polishing, machining and complex environments is improved, and the mold can be used in the field of molds.

The invention discloses a fatigue crack automatic segmentation and quantification method and device in a structural strength test, and the method comprises the steps: obtaining a material fatigue crack image, and constructing a material fatigue crack image data set; a fatigue crack segmentation and quantification network CrackDAM-Net is constructed; comprising the following steps: constructing a local feature encoder, a global information encoder, a multi-scale feature fusion module, a decoder module and a crack length automatic quantization module, and training a fatigue crack automatic segmentation and quantization network; and inputting a crack image to be detected into the fatigue crack segmentation and quantization network CrackDAM-Net, and carrying out crack segmentation and length quantization to obtain the fatigue crack length. According to the method, the calculation complexity of the model is reduced by constructing the fatigue crack segmentation and quantification network-CrackDAM-Net; the effective fusion of fine-grained details and coarse-grained information is realized, and the extraction effect of crack global information, the accuracy of crack segmentation and the precision of crack length measurement are improved.

The invention relates to the field of test methods, in particular to a method for estimating the fatigue crack growth rate of a corrosion-resistant metal composite material, which comprises the following specific steps: S1, preparing a sample, and measuring and recording the thickness B, the width W and the machining notch length am of the sample; s2, prefabricating fatigue cracks; s3, selecting test parameters; s4, carrying out a fatigue crack growth rate test; s5, calculating the opening displacement variation (delta delta) of the crack tip; s6, forming a data group, analyzing a distribution rule and establishing a mathematical model; and S7, carrying out damage tolerance design and fatigue life check. According to the method, the crack tip opening displacement variation delta delta is used as a driving parameter to describe the fatigue crack propagation rule of the corrosion-resistant low-strength high-plasticity metal material and the composite material of the high-strength low-plasticity metal material; the method can solve the crack propagation problem that K is only suitable for elastic or small-range yield and r cannot be fully covered under the condition of plastic yield.

The invention relates to the technical field of intelligent scheduling, in particular to a steel structure weld fatigue cracking real-time monitoring system based on machine vision, which is characterized in that an image acquisition module acquires a high-stability image sequence in a strong vibration environment; the displacement field reconstruction module adopts a frequency domain-space domain combined decomposition technology to isolate environmental noise and material non-uniformity interference in a breakthrough manner, and an anti-noise deformation field and a stress distribution diagram are synchronously output through dual-channel parallel processing; a damage response module accurately locks sub-pixel-level crack initiation coordinates based on strain energy accumulation rate mutation, and dynamically predicts a yield risk area in combination with a displacement gradient diffusion model; the early warning module intelligently triggers graded response according to the crack position and the space coupling state of the risk area, performs positioning maintenance in a low risk area and automatic strengthening in a high risk area, and outputs heat treatment scheme coordinates when no crack exists; the system solves the problems of false detection caused by vibration noise and lagging response of single-parameter monitoring, and active protection from damage initiation to failure blocking is realized.

The invention discloses a spherical tank structure damage identification method based on optical fiber sensing network information. In the service process of a spherical tank, damage such as local cracks, corrosion and fatigue cracking may occur, and a traditional detection method has the problems of low efficiency, limited range, low sensitivity to tiny damage and the like. According to the method, the load and damage characteristics of the spherical tank structure are analyzed, quasi-distributed optical fiber sensing devices and layout are designed, an effective multi-scale optical fiber sensing information network is established, and the damage of the spherical tank structure is identified by sensing strain and temperature information, a structure theory and a data analysis method. A spherical tank structure damage source mode recognition method is developed based on continuously monitored mass data information and a BP neural network algorithm, damage types, positions and degrees are determined, and corresponding damage sensitivity indexes and early warning thresholds are established. According to the invention, the problem of difficulty in positioning and identifying the damage of the spherical tank structure is solved, the accuracy and efficiency of online monitoring are improved, and reliable technical guarantee is provided for safe operation of the spherical tank.

The invention discloses a new energy automobile motor shaft damage detection method, and relates to the technical field of mechanical part tests.The new energy automobile motor shaft damage detection system comprises an eddy current detection module, an ultrasonic detection module and a track setting module, and the eddy current detection module sweeps a motor shaft through an eddy current detection method; the estimation module is used for estimating approximate distribution of distortion cracks and fatigue cracks, the ultrasonic detection module is used for scanning axial areas of the distortion cracks and the fatigue cracks by adopting a spiral scanning method and a circumferential stepping scanning method, and the track setting module is used for setting a scanning track according to the axial distribution of the fatigue cracks and the distortion cracks. The eddy current detection module comprises an eddy current sensor, a signal processing unit and a data acquisition module, the signal processing unit is electrically connected with the eddy current sensor, and the data acquisition module is electrically connected with the signal processing unit.

The invention discloses a method for estimating the fatigue crack propagation rate of a laminated structure, and belongs to the technical field of laminated structure fatigue crack prediction. The invention aims to solve the problem that the prediction of the existing fatigue crack growth rate cannot be separated from experimental data support. Comprising the following steps: dividing a laminated structure into an upper sub-beam and a lower sub-beam, calculating tangential displacement and normal displacement of a crack interface, and calculating tangential traction force and normal traction force of the layered crack interface by combining the interface fracture toughness of the laminated structure; calculating the total strain energy of the laminated structure by combining the internal stress resultant force, the bending moment and the shear stress resultant force of the upper sub-beam and the lower sub-beam; establishing a laminated structure balance equation and obtaining a control equation set; and solving the control equation set to obtain the theoretically calculated crack length, cycle index, upper sub-beam applied load theoretical value and upper sub-beam displacement theoretical value of the laminated structure under the fatigue load of the laminated structure, calculating to obtain the cycle energy release rate, and further calculating to obtain the crack growth rate. The method is used for estimating the fatigue crack growth rate.

The invention relates to the technical field of highway engineering monitoring, in particular to an acoustic emission diagnosis method and system for fatigue cracks of a heavy-duty highway, and the method comprises the steps: collecting acoustic emission signals by a multi-depth piezoelectric ceramic sensor array pre-buried in a pavement structure; carrying out time-frequency domain topological feature extraction on the collected signals, wherein the time-frequency domain topological feature extraction comprises wavelet packet entropy value mapping and phase-space reconstruction, and extracting topological invariants such as correlation dimensions and Lyapunov indexes; inputting the time-frequency feature vector into a transfer learning model to realize multi-scale feature fusion, and innovatively adopting a gradual change domain to realize smooth transition from a source domain to a target domain; a fractal stress field model is constructed based on the fusion features, and stress diffusion depth estimation and crack evolution prediction are achieved; a crack propagation area is automatically marked through correlation coefficient analysis, a crack temperature diagram is generated, and a maintenance decision suggestion is output, so that early-stage microcrack detection of the heavy-load highway is realized, the detection sensitivity is improved by about 35%, and the depth positioning precision reaches + / -1.5 cm.

The invention discloses a 42CrMo fatigue crack propagation rate prediction method based on machine learning, and the method comprises the steps: obtaining a corresponding relation among a stress intensity factor, a stress ratio and a fatigue crack propagation rate of a 42CrMo material through a fatigue crack propagation test, and taking the corresponding relation as an original data set; dividing the preprocessed original data set into a training set and a test set, constructing a fatigue crack growth rate prediction model, training the model by adopting the training set, and evaluating the trained model by adopting the test set; and inputting the actually measured stress intensity factor and stress ratio of the 42CrMo material to be predicted into the prediction model obtained in the step 3, and outputting through the prediction model to obtain a predicted value of the fatigue crack growth rate of the 42CrMo material to be predicted. According to the method, the fatigue crack growth rate of the 42CrMo material can be efficiently and accurately predicted at low cost, so that the service life of the wind power bearing is prolonged, and potential safety hazards are reduced.

The invention discloses a rubber composition for tire crown components, specifically related to the field of rubber, including the following raw materials by weight: 100 parts of diene rubber, 0.3-3 parts of hydrazide compounds, 40-160 parts of reinforcing fillers, 0-1.5 parts of low rolling resistance modifiers, 2-18 parts of silane coupling agents, vulcanization accelerators, vulcanizing agents, antioxidants, vulcanization activators, processing aids, resins and plasticizers. Hydrazide compounds can improve the compatibility between rubbers, and after complexing with zinc oxide, stabilize sulfur cross-linking bonds, thereby improving fatigue crack resistance, delaying crack initiation, reducing crack propagation rate, and improving physical property retention after aging. Low rolling resistance modifiers can react with the double bonds of synthetic diene rubbers in a trans-Diels-Alder reaction, which has the effect of reducing rolling resistance. Hydrazide compounds and low rolling resistance modifiers are used together, and the rubber composition has the performance of anti-fatigue, anti-crack growth, anti-collapse and block falling, low hysteresis loss, low heat generation, and low rolling resistance.

The utility model discloses a shockproof bearing, which belongs to the technical field of bearings and comprises a bearing body and a damping pad, the damping pad is arranged on the outer diameter of the bearing body, lock sleeves are arranged at two ends of the bearing body, exhaust holes are arranged on the outer diameters of the bearing body and the damping pad, and the exhaust holes are communicated with the lock sleeves. The outer diameter of the bearing body and the outer diameter of the damping pad are each provided with an oil injection hole, meanwhile, the outer diameter of the bearing body and the outer diameter of the damping pad are each provided with an oil outlet hole, four first fixing columns are fixedly installed on the outer diameter of the damping pad, and meanwhile the other ends of the first fixing columns are connected with second fixing columns in a sliding mode. In the actual use process, the stress borne by the bearing in the operation process can be dispersed, and when vibration or impact occurs, the stress can be absorbed and dispersed to a larger area by the buffering part instead of being concentrated on a certain part, so that the fatigue damage risk of the bearing part is reduced, and the service life of the bearing part is prolonged. And the bearing is not easy to generate fatigue cracks and other failure forms in the long-time use process.

The invention relates to a visual method for measuring the expansion rate of an ultrahigh-cycle fatigue internal crack, and belongs to the technical field of measurement of the expansion rate of the fatigue internal crack. A high-speed infrared camera is used for recording a temperature field generated by energy dissipation so as to visualize the crack propagation process, precise positioning of a fatigue crack initiation point of a metal material and in-situ monitoring of the crack propagation process are realized, and the crack propagation rate is obtained by introducing propagation time and load cycle frequency for calculation.

The invention provides a method and system for evaluating fatigue crack life of a welding structure under a random load, and relates to the technical field of rail transit, and the method comprises the steps: recognizing a load peak value and a load valley value through a point-by-point extreme value extraction method, and generating an equivalent variable-amplitude load data set; initial crack propagation rate parameters C and m and stress intensity factor distribution are calculated, and then a deterministic crack propagation increment result is output; a hierarchical Bayesian framework is combined with an MCMC sampling method, and global parameter distribution considering material heterogeneity and observation noise is generated through a posterior distribution formula; predicting crack depth evolution curves under different confidence coefficients, and outputting fatigue life probability distribution and confidence intervals; and finally generating a fatigue life reliability evaluation report of the welding structure under the random load. The method has the beneficial effects that the problem of fatigue crack propagation of the railway vehicle welding structure under the action of the complex random load can be better solved, and more accurate and reasonable technical support is provided for reliability evaluation of the welding structure.

The invention relates to the technical field of nondestructive testing of engine blades, and discloses an in-service in-situ electromagnetic acoustic detection system and method for aero-engine blades, which adopt an integrated design of an array eddy current sensor and an array surface wave sensor, ensure that dangerous cracks exposed out of a blade tenon can be reliably detected by an eddy current method, and meanwhile, improve the detection accuracy of the blade tenon. The internal fatigue damage can also be detected by an ultrasonic method, so that the engineering application problem that the embedded fatigue crack of the blade tenon of the aero-engine cannot be effectively detected in situ is solved.

The invention relates to a phosphorus-dilute anisotropic fatigue life regulation and control method. The method comprises the following steps: (1) establishing a molecular dynamics fatigue model consisting of a phosphorene sheet with a semicircular prefabricated defect; (2) executing a simulation process and processing data: (1) when fatigue crack initiation in the Armchair direction of phosphorene is explored, rotating the model by 90 degrees and then cutting; (2) when the movement direction is the Zigzag direction, the excitation frequency is 0.027 THz-0. 05 THz; when the motion direction is an Armchair direction, the excitation frequency is 0.0315 THz to 0.05 THz; under the condition that the excitation amplitudes are respectively 2, 3 and 4, calculating the fatigue life of the phosphorene in different motion states so as to analyze the influence of the change of the excitation frequency and the excitation amplitude in different directions on the fatigue life of the phosphorene. The internal mechanism of the fatigue failure mechanism and the fatigue life difference is disclosed from the angles of stress distribution, energy dissipation rate and phonon characteristics.

The utility model provides a T-shaped component structure used for repairing cracks at a welding seam of a steel bridge deck cover plate and a U-shaped rib, which comprises a steel bridge deck, the steel bridge deck comprises the cover plate, the U-shaped rib is welded below the cover plate, a part of the cover plate at a fatigue crack position on the steel bridge deck and a part of U-shaped rib side web plate connected with the part of the cover plate are cut off to form a mounting hole, and the U-shaped rib is welded below the mounting hole. A T-shaped component is mounted on the mounting hole, the T-shaped component comprises a flange plate welded with the edge of the cover plate on the mounting hole, and an inclined web plate welded with the edge of the U-shaped rib side web plate on the mounting hole is arranged on the plate surface of one side of the flange plate. The structure is reasonable, construction is convenient and fast, the problem of crack fatigue at the position of the orthotropic steel bridge deck slab cover plate and the U rib is effectively solved, the service life of the steel box bridge deck slab is prolonged, and the fatigue problem of the steel box bridge deck slab is reduced.

The utility model relates to the technical field of traction motor bearing manufacturing, in particular to a deep groove ball bearing which comprises an outer ring, an inner ring, a plurality of rolling bodies and a retainer, the outer surface of the inner ring and the inner surface of the outer ring are respectively provided with a roller path for the rolling body to roll; the rolling body is located between the outer ring and the inner ring, and the retainer is located between the outer ring and the inner ring; the guide mode of the deep groove ball bearing is rolling body guide; the groove curvature coefficient of the outer ring is 0.520 Dw, and the groove curvature coefficient of the inner ring is 0.510 Dw. The curvature coefficient of the inner and outer ring channels is reduced by 0.005 Dw compared with a conventional bearing, and the contact area of the raceway and a rolling body is increased under the condition, so that the load borne by the unit area is reduced, the stress concentration and fatigue crack possibility is reduced, the operation temperature rise and vibration of the bearing under the high-speed working condition are reduced, and the fatigue life of the bearing is prolonged.