82 results about "Crack size" patented technology

The invention discloses a bridge crack detection system based on bridge safety, and relates to the technical field of bridge safety detection, and the system comprises a region division module which divides a bridge structure into a key detection region and a secondary detection region according to bridge historical detection data; the data acquisition module is used for respectively arranging corresponding detection equipment in the key detection area and the secondary detection area and acquiring the number, the size and the specific position of cracks in real time, and the sizes of the cracks comprise large cracks and small cracks. The method is beneficial for determining whether the cracks which seem not to threaten the safety of the bridge can gradually evolve into potential hazards which influence the overall safety of the bridge under the combined action of the cracks and other cracks, so that more accurate and reliable technical support is provided for safety management and maintenance of the bridge.

The invention discloses a PCB circuit microdefect real-time detection algorithm optimization method based on artificial intelligence, and relates to the field of printed circuit board monitoring, and the method comprises the steps: collecting multi-physical field data including a temperature field, a stress field, current density distribution and corrosion medium concentration in real time; generating time-space synchronous multi-modal fusion data; quantifying a thermal-mechanical-electric-chemical field interaction relationship through an inter-field coupling coefficient matrix; generating a four-dimensional synergistic effect matrix through tensor fusion; and based on the four-dimensional synergistic effect matrix, in combination with a spatio-temporal evolution diagram output by the carbonization path prediction model, establishing a three-dimensional mapping relationship among the crack size, the carbonization path and the material residual strength, and predicting a residual life prediction value. The method has the advantages that through real-time synchronous fusion of multi-physical field data and tensor coupling modeling, accurate tracking of a crack propagation path and dynamic evaluation of the residual life are achieved, the detection sensitivity is improved, and the life prediction error is reduced.

The invention relates to the technical field of crack monitoring, in particular to a concrete structure crack full-life-cycle monitoring method and system, and the method comprises the following steps: arranging sound wave points to obtain a stress change to generate an initial signal, extracting an image feature recognition extension path, analyzing a size acceleration to generate an extension identifier, and screening an active cycle at intersection time to generate an evolution fragment. And classifying crack behaviors according to displacement and width trends to generate an annotation set. According to the method, stress evolution is reflected based on interval transit time, a crack expansion trend is extracted in combination with an image feature point track, an active state is identified by superimposing crack size speed increase synchronism, a high-frequency change fragment is positioned through multi-index time intersection, and crack behavior types are divided according to a displacement direction and a width increase trend. Continuous tracking and classified marking of the whole process from crack starting to evolution are achieved, the response capacity to abnormal crack behaviors is enhanced, and the precision and timeliness of structural safety state recognition are improved.

The invention relates to an aero-engine stator part crack critical dimension comprehensive determination method and system, and belongs to the technical field of aviation, the method comprises the following steps: obtaining an aero-engine typical hot end stator part geometric model and material parameters, and carrying out static strength analysis according to fluid-thermal-solid coupling load characteristics in actual working conditions; inserting an initial crack into a first principal stress plane of a dangerous part of the real component, carrying out crack propagation simulation to determine a crack propagation path, and calculating a critical crack size of a dangerous point; analyzing critical crack sizes under different failure modes, such as cooling failure and buckling failure; and integrating analysis results under the multi-failure mode, and determining a comprehensive critical dimension as a final judgment standard. According to the method, through combination of fracture failure and function failure analysis, accurate judgment of the critical dimension of the crack is realized, limitation of a traditional single fracture criterion is broken through, comprehensive function failure analysis is realized, the accuracy of a maintenance decision is remarkably improved, and a scientific basis is provided for condition-based maintenance decision.

The invention discloses a PINN-based power module welding spot failure detection and life prediction method and system, and belongs to the field of power module detection.The method comprises the steps that electric, thermal and mechanical force multi-physical field real-time monitoring is conducted on a welding spot, and a heat conduction equation, an improved Coffin-Manson equation and a Paris law are constructed; constructing a three-constraint PINN network architecture and setting a network training strategy; and inputting real-time monitoring data into the trained PINN network, and synchronously outputting three groups of prediction results of the welding spot residual life percentage, the critical crack size early warning value and the high-temperature dangerous area coordinate. According to the invention, the failure mechanism of the welding spot can be reflected more comprehensively and accurately, and the detection accuracy is improved.

The invention relates to the technical field of material mechanical property testing, and discloses a material indentation and scratch testing device and method under a composite energy field, and the device comprises a supporting experiment table, a vertical micro-motion platform, a horizontal micro-motion platform, a high-definition optical microscope, a force sensor, a displacement sensor and an additional energy field generation system. According to the method, a controllable additional energy field is synchronously applied while a mechanical indentation or scratch load is applied to a hard and brittle material sample, and load displacement data is collected in real time. In the data processing stage, the real hardness is calculated by adopting a corrected proportion sample resistance model, the elastic modulus is calculated based on the Oliver-Pharr theory, and the fracture toughness of the material is analyzed and calculated according to the size of the indentation tip crack. The problem that in-situ mechanical property characterization cannot be carried out in a composite energy field in a traditional test is solved, the hardness calculation precision is improved, the fracture toughness measurement function is expanded, and the experimental device and method are provided for research of a hard and brittle material composite machining mechanism.

The invention discloses a damage tolerance evaluation method and system for a friction plug repair welding joint of a carrier rocket storage tank, and the method comprises the steps: detecting an interface of the friction plug repair welding joint of the carrier rocket storage tank, and obtaining defect information, constitutive parameters of a material, and material attributes; establishing a finite element model, and accurately setting corresponding distribution interface defects; quantizing in-plane and out-plane restraint effects of the crack tip by adopting restraint parameters; processing and preparing a unilateral notch tensile sample, and measuring a local J-R curve of the tip of the precrack at the interface of the friction plug repair welding joint; correcting a real J-R curve of the friction plug repair welding joint of the rocket tank based on the influence of the distribution interface defect characteristics; then the tensile strength values of the friction plug repair welding joint in all the positions in the circumferential direction are corrected, and a corrected real J-R curve is obtained; and the limit crack size under the action of the corresponding internal pressure is obtained by utilizing the crack tip extension driving force curve, and then the critical J integral of the crack is calculated, so that the maximum crack size under the specific load or the maximum internal pressure under the crack with the specific size is obtained.

The invention discloses a multi-mode Internet of Things monitoring and early warning system for old building structure cracks, the multi-mode Internet of Things monitoring and early warning system comprises sensor nodes, an edge gateway and a cloud platform, the sensor nodes comprise a temperature sensor, a humidity sensor, a vibration sensor and a displacement sensor, the data acquisition module is used for periodically acquiring crack width change and temperature, humidity and vibration data around a crack; the edge gateway is used for receiving the sensor data and executing local calculation according to the sensor data, the local calculation comprises calculating the pressure-bearing stress of the crack, calculating an environment comprehensive influence coefficient and calculating a crack risk comprehensive index, and the cloud platform is used for receiving the calculation data of the edge gateway and executing risk judgment according to the crack risk comprehensive index. According to the method, the multi-factor monitoring process of the building structure crack is realized by fusing the crack size, the environmental parameters and the structural load data in real time, and the crack risk level can be evaluated more accurately by dynamically correcting the pressure-bearing stress and environmental coupling effect.

The invention belongs to the technical field of nondestructive flaw detection, and particularly relates to a crack quantification method for enhancing an alternating current electromagnetic field based on a bias magnetic field. According to the crack quantification method, the reliability of a crack size quantification result is improved, the signal indication performance of an alternating-current electromagnetic field on the surface crack and the internal crack is enhanced, and the detection rate of the surface crack and the internal crack is increased. The crack quantification method based on the bias magnetic field enhanced alternating current electromagnetic field comprises the following steps: setting a calibration crack; obtaining an alternating current Bx signal of each calibration crack; a reset new Bx signal is obtained; solving the sensitivity of the new Bx signal; calculating a kernel function between the calibrated crack sizes; calculating log edge likelihood; calculating to obtain a mean value of each new size data point and a variance of each new size data point; and obtaining an alternating current signal of the crack to be quantized, obtaining a crack depth value-sensitivity quantization curve and a depth prediction value of the crack to be quantized, and solving to obtain the confidence coefficient and variance of the depth prediction value of the crack to be quantized.

The present application proposes a method and device for spraying a composite coating using laser shock thermal imaging based on vision guidance, wherein the method comprises: generating a transient thermal response on the coating surface by laser shock, and using a high-speed infrared thermal imager to collect the temperature field distribution on the coating surface in real time; identifying the crack position according to the temperature field distribution on the coating surface, and obtaining the thermal response characteristics of the crack area on the coating surface, wherein the thermal response characteristics include the real-time temperature and temperature gradient data of the crack area; establishing a nonlinear mapping model between the crack thermal response characteristics and the crack size, and using a deep neural network for training, inputting the thermal response characteristics after data preprocessing into the trained deep neural network, and predicting the size and spatial position of the crack in real time; setting the target spraying parameters based on the predicted crack size information, adjusting the spraying process parameters in real time through a self-feedback PID control system, and using a multi-channel powder feeding system to dynamically adjust the material ratio to achieve the formation of a gradient composite coating.

The invention relates to a fatigue crack propagation simulation and life prediction method considering a crack closing effect. The method comprises the following steps: constructing a finite element model; assembling crack sizes in the finite element model according to user requirements, refining regional grids of the cracks, expanding the cracks in the finite element model, extracting a displacement field of the regional grids at the tips of the cracks, performing nonlinear calculation considering a crack closing effect on the basis of the displacement field, and calculating the crack closing effect. Obtaining an I-type stress intensity factor and an II-type stress intensity factor at the tip of the crack; calculating a crack propagation angle based on the I type stress intensity factor and the II type stress intensity factor and based on a maximum circumferential stress criterion, and calculating a new crack tip coordinate based on the crack tip coordinate, the crack propagation angle and a user-defined crack propagation increment; and updating historical crack tip coordinates based on the new crack tip coordinates to update the cracks, and assembling the finite element model until the I-type stress intensity factor is greater than the fracture toughness, and outputting a result in a table form.

The invention relates to the technical field of mechanical structure strength evaluation and structural design, and provides a safety evaluation and design method for a ship longitudinal welding structure, which comprises the following steps: determining a damaged key part; detecting the size of the minimum detectable crack in the ship longitudinal welding structure by adopting a nondestructive detection method; carrying out regularization and normalization processing on the crack obtained by detection; calculating a stress intensity factor amplitude corresponding to the current crack; judging whether the crack is expanded or not by combining a fatigue crack expansion threshold value predicted by a Zhu-Xuan model; based on a nondestructive testing result and a three-dimensional crack propagation analysis model, establishing a crack propagation digital twinborn body; and according to crack propagation prediction results and residual life evaluation results of the crack propagation digital twin under different structure schemes, safety and reliability of different welding structure forms, size parameters and process schemes are compared, and optimal design of the ship longitudinal welding structure is achieved.

The application discloses a micro-nano circular plate fracture analysis method considering coupling of surface effect and plastic zone, and firstly establishes a three-dimensional curved surface coordinate system suitable for a surface layer, and then further corrects a Dugdale cohesion force model according to a superposition principle after considering surface correlation of the plate, and then simplifies the Dugdale cohesion force model into a hyper-singular integral equation by using Hankel transformation, and finally obtains influences of the surface effect on the plastic zone size and crack surface displacement by numerically solving the hyper-singular integral differential equation.The method can accurately capture the nonlinear coupling relationship between the crack size, the surface shear modulus, the torsional displacement and the stress intensity factor under the micro-nano scale, effectively corrects calculation deviation generated by traditional classical theory when the surface effect is ignored, ensures the accuracy of the fracture analysis under different scales, and realizes more accurate and more comprehensive theoretical description of the elastic-plastic fracture behavior of the micro-scale material.

The invention relates to a nuclear power plant main pipeline damage tolerance establishment method. The method comprises the following steps: S1, determining the critical crack size of the main pipeline of the nuclear power plant at the end of the life; and S2, performing finite element calculation based on the established finite element model of the crack-free structure of the main pipeline so as to obtain stress distribution of the crack-free structure under each load working condition. S3, according to the initial crack size and the finite element calculation result, stress intensity factor calculation, transient pairing, elastic-plastic correction and fatigue crack propagation calculation are conducted in sequence, and the life end crack size of the main pipeline is obtained. And S4, when it is judged that the life end crack size of the main pipeline is smaller than the critical crack size, the step S3 is executed again to conduct iterative calculation on the initial crack size. And when the final crack size of the service life of the main pipeline is judged to be greater than the critical crack size, taking the initial crack size updated by the last iteration as the structural damage tolerance. The nuclear power pipeline defect evaluation period can be shortened, and the evaluation efficiency is improved.

The invention discloses a crack tolerance analysis method for a saddle-shaped welding seam of an integral reinforcing connecting pipe of nuclear pressure-bearing equipment, and belongs to the technical field of reliability. The method comprises the following steps: firstly, establishing a three-dimensional model containing a crack structure and defining crack parameters; carrying out finite element analysis after applying a load; and the critical crack size is determined by iteratively adjusting the crack depth in the failure evaluation diagram. Carrying out sampling analysis by taking the load and the material parameters as random variables to obtain a critical crack size set; and finally, the failure probability reaches a target allowable value by adjusting a crack detection threshold value of nondestructive testing. According to the method, finite element simulation is carried out, the critical crack size of the saddle-shaped welding seam of the integral reinforcing connecting pipe of the pressure-bearing equipment under the complex load is checked based on a failure evaluation icon, the relation between the critical crack size and the allowable crack size is established by assuming that the crack size detected by nondestructive testing obeys normal distribution, and the test efficiency is improved while the number of experiments is reduced. And the reliability of a calculation result is ensured.

The invention belongs to the field of wheel-rail tribology, and particularly discloses a wheel-rail fatigue crack intelligent quantitative characterization method based on microscopic analysis images, which comprises the following steps: carrying out image enhancement and noise reduction preprocessing on scanning electron microscope and optical microscope images of wheel-rail rolling contact fatigue cracks; inputting the image into a YOLOv8-CSSTAM model for target detection, and outputting an image crack prediction frame and a proportional scale prediction frame; on the basis of an automatic calibration algorithm of an image scale, calculating the widest connected region of the image in the scale prediction frame, and performing OCR character recognition to obtain the image scale; performing median filtering, threshold segmentation, edge smoothing and small area filling processing on the crack image in the crack prediction frame; carrying out Harris corner detection on the processed image to obtain candidate corners; and screening the angular points to obtain crack feature angular points, and then calculating crack size features. The method can quickly and accurately obtain crack information in the wheeltrack rolling contact fatigue crack image, wherein the crack information comprises the crack depth, the crack width and the crack propagation angle.

The invention relates to the technical field of tunnel apparent disease detection, in particular to a tunnel apparent disease detection method and system based on depth vision, and the method comprises the steps: carrying out the tunnel crack pre-recognition of a tunnel image through employing an improved Deeplabv3 + model, generating a pre-recognition result image, and carrying out the recognition of a tunnel crack; wherein in the improved Deeplabv3 + model, an ASPP structure is replaced by a multi-feature ASPP structure, and the expansion rate of a feature layer is increased; an improved seepage model is adopted for recognizing tunnel cracks in the pre-recognition result graph, a recognition result graph is generated, and the improved seepage model conducts crack recognition by extracting a crack skeleton to select seed points and introducing crack features; and according to the identification result graph, carrying out conversion and crack size measurement by adopting a chessboard calibration and orthogonal skeleton line method, and generating a crack size measurement result. According to the scheme, the omission ratio can be reduced, the precision, accuracy and detection efficiency are improved, and tunnel driving safety is guaranteed.

The utility model relates to the technical field of slitting machines, in particular to a slitting machine with an edge wire breakage alarm function, which comprises a slitting machine body, a mounting support is arranged on the side portion of the slitting machine body, and an annular proximity switch high-speed sensor is arranged at the top end of the mounting support. A protective sleeve is arranged on the inner ring of the annular proximity switch high-speed sensor, a bag body to be cut penetrates through the protective sleeve, a control box is further arranged on the slitting machine body, a control processor is arranged in the control box, an alarm is further arranged on the slitting machine body, and the annular proximity switch high-speed sensor and the alarm are connected with the control processor. According to the utility model, the thin strip edge wire penetrates through the annular proximity switch high-speed sensor, the inductor gives an alarm when the edge wire is broken, and a quality inspector can stop a unit to confirm and judge the size of a crack for repair treatment, so that the product quality is ensured, and customer complaints caused by the crack problem are prevented.

The present application relates to the technical field of computer vision and road engineering, and particularly relates to a pavement crack lightweight segmentation and quantification method based on enhanced feature fusion. The method comprises the following steps: decoding and reading pavement images and performing verification, then performing grid division and cutting, and performing pixel normalization processing on the effective sub-images after cutting; a lightweight crack segmentation network is constructed; the preprocessed standard images are input into the lightweight crack segmentation network, and feature extraction, feature fusion, target detection and pixel segmentation are sequentially completed, and a crack detection frame and a binary segmentation mask are output; the lightweight crack segmentation network is trained, the optimal model is saved according to the iteration optimization of the verification set index; the segmentation mask output by the model is denoised, the crack geometric size is calculated, and the final detection quantification result is output. The method has the advantages that the small-scale crack recognition capability is improved, the crack length and width can be automatically and accurately measured, the crack size measurement error is small, and the method is suitable for large-scale pavement inspection operation.

The invention discloses a part interlayer fracture toughness test method, device and equipment and a storage medium, and the method comprises the steps: applying different loading forces to a standard test part based on a mechanical test system, and obtaining test data of each test point at different test moments through a digital image correlation technology DIC; performing top-hat transformation processing on the test image of each test point to obtain a processed test image, and obtaining the size of the precrack according to the processed test image; and calculating according to the precrack size and the loading force of each test point at different test moments to obtain the interlayer fracture toughness of the standard test part. The method comprises the following steps: on the basis of acquiring crack opening displacement and angle of a fiber reinforced composite material I-type interlayer fracture toughness test piece through DIC, synchronizing the dynamic change process of the length of a prefabricated crack extending along with loading of a load at different moments with a real-time load, and meanwhile, optimizing an acquired test image by combining a Top-hat technology, so as to obtain a test result of the I-type interlayer fracture toughness of the fiber reinforced composite material I-type interlayer fracture toughness of the fiber reinforced composite material I-type interlayer fracture toughness test piece. And the measurement precision of the interlayer fracture toughness is improved.

The present invention relates to a processing device and method for fracture toughness specimens of aviation non-metallic materials, comprising a special slotting tool, a special Y-shaped saw 1, and a clamping and positioning fixture. The clamping and positioning fixture includes a reference positioning U-shaped block 6, each vertical side of which is machined with a Y-shaped groove 9 having the same structure as the special Y-shaped saw blade 4. The Y-shaped groove 9 includes an upper rectangular groove, a middle V-shaped groove, and vertically distributed cracks. A specimen 10 is sandwiched between the two vertical sides of the reference positioning U-shaped block 6. The specimen rests on the horizontal side of the reference positioning U-shaped block 6. The special Y-shaped saw passes through the Y-shaped groove 9 and machines prefabricated cracks 12 on the specimen 10 along the vertically distributed cracks. The present invention is very suitable for batch processing of prefabricated cracks. The processed cracks have high dimensional consistency and stable quality, which is of great significance for accurately characterizing the test results of the mechanical properties of the specimens.

The utility model relates to a hydraulic ring geological crack measuring device, which belongs to the technical field of crack measurement and comprises two supporting columns, lifting frames are arranged on the sides, close to each other, of the two supporting columns, sliding plates are slidably mounted on the outer sides of the lifting frames, and measuring rods are fixedly connected to the bottom ends of the sliding plates. Servo motors are fixedly mounted at the bottom ends of the inner walls of the sliding plates, and gears are fixedly connected to output shafts of the servo motors. The beneficial effects of the utility model lie in that the rotation of the output shaft of the servo motor can drive the gear to rotate, so that the gear can roll on the rack, the sliding plate can be driven to move, the position of the measuring rod can be moved to the geological fracture measuring position, and the measuring rod can be moved to the geological fracture measuring position in the measuring process. A worker can measure the size of the crack without approaching the edge of the crack, so that the use safety of the device can be improved, and the life safety of the worker is ensured.

The invention discloses an unmanned aerial vehicle for high-altitude crack measurement and a measurement method thereof. The unmanned aerial vehicle for high-altitude crack measurement comprises an unmanned aerial vehicle body, a laser range finder, a camera module and an upper computer, the laser range finder comprises an emitter and is used for measuring the distance between the laser range finder and a detected wall surface and forming a light spot on the detected wall surface; the shooting direction of the camera module is consistent with the light emitting direction of the emitter, and the camera module is used for shooting the light spot and the detected crack to the same picture; the upper computer is used for judging whether the light emitting direction is perpendicular to the detected wall surface or not according to the shot picture and calculating the size of the crack; the laser range finder and the camera module are arranged on the unmanned aerial vehicle body. The method has the advantages that the perpendicularity with the wall where the crack is located during shooting is detected, and the accuracy of crack size calculation is improved.

The present application relates to the technical field of sealing material testing, and specifically discloses a system and method for testing the air tightness and deformation performance of sealing materials under crack lapping, which comprises a gas pressure adjusting module, a sealing box module, a temperature environment control cabin and a monitoring module. The monitoring module is used to collect data such as the temperature, pressure, volume and deformation of the sample of each component. The collected data can be used to calculate the intrinsic permeability coefficient of the sealing material sample, the displacement deformation when the crack is lapped, the puncture failure pressure and the permeability coefficient when the crack is lapped. The sample pad component in the system is an important part of the sealing box module. It can simulate the size and shape of the crack lapped with the sealing material according to the need. In combination with the gas pressure adjusting module and the monitoring module, the system can realize the testing of the permeability, deformation and puncture failure resistance performance of the sealing material under various working conditions.

The invention discloses a high-speed railway RCF crack size characterization method based on an ACFM technology By signal. The method comprises the steps that a finite element model of a high-speed railway steel rail is established; adopting a control variable method, taking one of the crack length, the crack pocket depth and the crack inclination angle as a variable and taking the other two of the crack length, the crack pocket depth and the crack inclination angle as a fixed quantity, carrying out ACFM detection simulation, detecting the crack to obtain a By signal, and extracting characteristic parameters of the By signal; obtaining a quantitative relationship between the By signal characteristic parameter and the crack geometric parameter; based on the quantitative relationship, establishing a By signal-crack size mapping model through a polynomial regression algorithm or a support vector regression algorithm; inputting a to-be-measured By signal into the By signal-crack size mapping model, and outputting three quantitative results of the crack length, the crack pocket depth and the crack inclination angle. The method not only provides a theoretical basis for developing a more comprehensive ACFM quantization algorithm, but also lays a technical foundation for online intelligent monitoring and maintenance of the high-speed railway steel rail.

The present application belongs to the field of fatigue life calculation, and particularly relates to a method for calculating the crack propagation life of a wheel considering a restricted load condition. The method comprises: obtaining the stress or strain distribution of the wheel under the action of a Class I cyclic peak load condition; prefabricating an initial crack at a characteristic portion of the wheel to obtain a stress intensity factor distribution curve of the initial crack front; performing crack propagation under the action of the Class I cyclic peak load condition according to the first crack propagation plan to obtain crack propagation morphologies of different crack propagation sizes; obtaining the stress or strain distribution of the wheel under the restricted load condition; calculating the maximum stress intensity factor of the crack front corresponding to each of the crack propagation morphologies; fitting the relationship curve between the crack propagation size and the maximum stress intensity factor to predict the critical crack size; and calculating the crack propagation life. The crack propagation life given in the present application is more conservative and safer.

This invention proposes a device for detecting micron-level cracks in in-pile materials under high temperature and high pressure, comprising a sealing head, a gas pipeline, a top cover, an outer sleeve, a double-layer corrugated pipe, a bottom cover, a CT sample block, a pressure sensor placement device, and a force-bearing rod. The double-layer corrugated pipe is connected to the gas pipeline, and a sealing head is installed on the gas pipeline. A top cover is installed between the first corrugated pipe and the gas pipeline. One end of the second corrugated pipe is connected to the force-bearing rod, and a bottom cover is installed between the second corrugated pipe and the force-bearing rod. The force-bearing rod is provided with a detection end fixing hole and a space. The CT sample block is located in the space, and the pressure sensor placement device is installed on the CT sample block. This application can simulate the load under actual application conditions and directly detect the size of the sample crack by reducing the DC potential, with an accuracy of micron-level. All parameter signals are transmitted to the host computer for display via serial communication, and parameters such as crack size changes, device temperature, device pressure, and excitation signal magnitude are monitored in real time.

The invention relates to a device and method for evaluating the crack healing capacity of a memory alloy fiber cement-based material, and belongs to the field of concrete crack healing, the device comprises a partition manufacturing mold and a crack prefabricating device, the partition manufacturing mold is used for manufacturing a low-melting-point alloy partition, and the partition size is consistent with the crack size of the cement-based material; the crack simulator is used for simulating cracks of cement-based materials; the crack prefabricating device comprises a test mold, a steel support and a steel clamp. A plurality of cement-based material pouring areas are arranged on the test mold; the multiple steel clamps are arranged on the steel support, located over the cement-based material pouring area and used for fixing the partition, and a plurality of memory alloy fibers are prefabricated on the partition. The crack healing capability is comprehensively evaluated by taking the crack closing rate as a main part and taking the shrinkage deformation utilization rate as an auxiliary part. According to the method, accurate control over the crack size, the fiber distribution direction at the crack and the length of the fiber unbonded area can be achieved, and reasonable evaluation on the crack healing capacity can be achieved.

The disclosure provides a high-temperature fatigue life prediction method based on EIFS, and relates to the technical field of reliability design. The method comprises the following steps: acquiring first test data of crack propagation test and high-cycle fatigue test on a smooth member, and second test data of test on a notched member; determining equivalent initial defect sizes of the smooth member and the notched member according to the first test data and the second test data; obtaining an equivalent stress intensity factor difference and a fatigue crack propagation rate of the notched member under a high-temperature condition according to the second test data; fitting a function relationship among the fatigue crack propagation rate, the equivalent stress intensity factor difference and a crack size to obtain a crack propagation function; and determining a predicted fatigue life of the notched member under the high-temperature condition based on the crack propagation function, the equivalent initial defect size of the notched member and a limit crack size. The disclosure can realize accurate high-temperature fatigue life prediction.

The invention discloses a pearlitic steel rail and a welding method of a joint thereof, the pearlitic steel rail is added with a specific amount of Ce element, and a specific joint welding method is adopted, so that the rail bottom pushing convex crack size of the obtained steel rail joint is reduced from more than 156 [mu] m to less than 25 [mu] m, and the average size of the pushing convex crack is reduced by more than 80%; the other structure properties of the joint meet TB / T 1632, meanwhile, the properties are remarkably improved, the average impact property is larger than 12.6 J, and the average hardness of the section hardness of the welded joint reaches 94%-98% of the average hardness of base metal.