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434 results about "Crack initiation" patented technology

High-strength concrete construction crack detection system and method

The invention belongs to the technical field of concrete crack detection, and particularly discloses and provides a high-strength concrete construction crack detection system and method.The system comprises a multi-parameter cooperative sensing module, a construction crack recognition module, a crack risk analysis module and a crack early warning processing module. According to the invention, the temperature, humidity, strain and multispectral image data from a plasticity stage to a hardening stage are collected in real time through the multi-parameter cooperative sensing module, and crack characteristics are extracted by combining staged differential signal processing and a deep convolutional neural network, so that the detection precision of micro cracks and internal defects is remarkably improved. Meanwhile, multi-physics field data are fused, a crack evolution risk rate model is innovatively constructed, dynamic probability prediction before crack initiation is achieved, a grading disposal scheme is automatically triggered through risk grade division and a progressive early warning mechanism, drying shrinkage and temperature crack causes are effectively distinguished, the prevention and control efficiency is remarkably improved, and the method is suitable for large-scale popularization and application. And full-life-cycle accurate monitoring of the high-strength concrete is supported.
Owner:CCCC FIRST ENG & CONSTR RES INST CO LTD +1

Coating performance analogue simulation method based on high and low temperature circulation and prestress loading

The invention relates to the technical field of material testing, and discloses a coating performance simulation method based on high and low temperature circulation and prestress loading. The method comprises the following steps: constructing a coating matrix composite geometric model containing a microporous structure by acquiring actually measured working condition data of a pipeline or a part, and quantifying surface roughness and interface curvature characteristics in combination with reverse engineering; a dynamic temperature-pressure coupling equation is generated based on the thermal expansion effect of a high-pressure medium, a micropore optical load is converted into equivalent heat flux density through a ray tracing algorithm, transient boundary conditions of a temperature field and a stress field are associated, a crack initiation path is simulated through an extended finite element method, and a life attenuation curve is predicted in combination with a Paris formula. And material parameters are dynamically corrected based on experimental data, and a multi-parameter collaborative optimization model is generated. According to the method, the problems of interface stress evaluation distortion and life prediction deviation under the combined load are solved, and multi-physics field co-simulation support is provided for coating compression resistance optimization.
Owner:이너 몽골리아 일렉트릭 파워 그룹 컴퍼니 리미티드 이너 몽골리아 일렉트릭 파워 리서치 인스티튜트 브랜치

System and method for dynamically detecting cracks of prefabricated box girder

The invention belongs to the technical field of prefabricated box girder crack detection, and particularly relates to a prefabricated box girder crack dynamic detection system and a prefabricated box girder crack dynamic detection method. The crack initiation position is efficiently identified from a single-source spectral image by utilizing spectral reflectivity difference, so that the crack detection efficiency is remarkably improved, and meanwhile, crack information and stress data are subjected to correlation analysis to determine a critical stress distribution state causing crack initiation, so that effective prediction of potential cracks is realized, and the accuracy of crack detection is improved. And meanwhile, after the crack is initiated, the crack propagation speed and the crack propagation direction are continuously monitored, so that the real-time tracking of the crack dynamic evolution process is realized, and targeted crack propagation response measures are taken by utilizing the risk orientation obtained by performing risk assessment in combination with a crack propagation monitoring result, so that the further propagation of the crack can be effectively prevented.
Owner:CHINA RAILWAY FIFTH GROUP SECOND ENGINEERING CO LTD +1

Detection method for quantitatively evaluating fatigue damage in pipeline through nonlinear ultrasonic technology

The invention belongs to the technical field of nondestructive testing, and particularly relates to a detection method for quantitatively evaluating fatigue damage in a pipeline through a nonlinear ultrasonic technology. 316 stainless steel and SA335GRP-11 ferrite steel samples are adopted, a welding seam area is formed through V-shaped groove welding, fatigue loading is conducted, and actual pipeline fatigue damage is simulated; for the samples with different fatigue cycles, nonlinear response signals of the samples are obtained; fourier transform is carried out on the obtained signal to obtain an energy spectrum of the signal, and energy changes of the signal on a fundamental frequency band and a second harmonic frequency band are analyzed; and calculating a nonlinear coefficient, and analyzing a change rule of the nonlinear coefficient along with fatigue cycles, so that the evolution process of fatigue damage in the pipeline is evaluated. According to the method, energy is used for replacing the amplitude value, on the basis of the formula principle, integration is used for replacing the amplitude value to improve the intensity of the characterization nonlinear ultrasonic signal, the early stage of damage and the later stage of crack initiation are detected, and reliable guarantee is provided for safe operation of an industrial pipeline system.
Owner:RES INST OF NUCLEAR POWER OPERATION +1

Machine vision-based real-time monitoring system for fatigue cracking of welding seam of steel structure

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.
Owner:CHINA RAILWAY FIRST GRP BUILDING & INSTALLATION ENG CO LTD

Anti-cracking hydrogen-doped pipeline system and performance degradation monitoring method thereof

The invention relates to the technical field of new energy pipelines, in particular to an anti-cracking hydrogen-doped pipeline system and a performance degradation monitoring method thereof. The hydrogen-doped pipeline system comprises a pipeline assembly, a supporting assembly, an operation assembly, a power assembly, a storage battery pack, a system control cabinet and a power generation assembly, the phenomena of hydrogen permeation and gas stratification are effectively inhibited through innovative pipeline structure design and material optimization in the system level, the hydrogen embrittlement risk is reduced from the source, and the energy consumption is reduced. According to the method, the hydrogen atom diffusion tracking and crack initiation prediction are combined, and a multi-scale collaborative monitoring system is constructed, so that the whole-process monitoring from hydrogen atom diffusion tracking to crack initiation prediction is realized, and particularly, a quantum dot marking technology is combined with a traditional sensing network, so that the service life of the pipeline can be effectively prolonged, and the reliability and the maintenance efficiency of safety monitoring are improved.
Owner:SHAANXI HUAYOU DINGXIN PIPELINE TECHNOLOGY CO LTD

Rock crack evolution numerical simulation method based on data analysis

The invention discloses a rock crack evolution numerical simulation method based on data analysis, and relates to the technical field of rock mechanics engineering numerical simulation, and the method comprises the following steps: S1, obtaining microstructure data of a target rock, including a CT scanning image, an SEM image and mineral energy spectrum data; and S2, constructing a spatial distribution dynamic mechanical parameter field based on the microstructure data. According to the rock crack evolution numerical simulation method based on data analysis, a dynamic mechanical parameter field driven by a microstructure is constructed, so that the inherent defect that rock is simplified into a homogeneous material in a traditional method is overcome; microscopic characteristics such as mineral hardness gradient, grain boundary strength distribution and pore morphology are effectively quantified into an elastic modulus field, a tensile strength field and a fracture energy field which are spatially distributed, so that the numerical prediction of crack initiation and expansion truly reflects the inherent heterogeneity of the rock for the first time.
Owner:JIANGSU VOCATIONAL & TECHNICAL UNIVERSITY OF ARCHITECTURE

Hydrofracture top-cutting entry retaining method based on crushing agent

The invention belongs to the technical field of safe mining of coal mines, and relates to a hydraulic fracturing roof-cutting entry retaining method based on a crushing agent, which comprises the following steps of: calculating to obtain a target fracturing horizon height h of roof-cutting entry retaining according to a working face height M and a residual crushing coefficient KZ of a roof; calculating the crack initiation pressure P of a target fractured position of the roof-cut entry retaining according to the rock stress P * and the tensile strength R of the rock at the fractured position of the roof-cut entry retaining; drilling is conducted according to the drilling position, the drilling length L and the drilling angle alpha; the prepared BC-efficient soundless cracking agent flowable pasty slurry is injected into a drill hole through a hydraulic fracturing system and is fractured at a target fractured layer, and after the BC-efficient soundless cracking agent flowable pasty slurry is subjected to standing reaction, the drill hole is fractured for multiple times in a single-hole retreating mode. The problems that a large amount of water resources are consumed, the rock permeability is possibly increased due to high-pressure water injection, and mine water disaster hidden dangers are caused are solved.
Owner:KUCHE YONGXIN MINING CO LTD +1

Shrinkage-free iron aluminate cement-based ultra-high performance concrete and preparation method thereof

The invention discloses shrinkage-free aluminoferrite cement-based ultra-high performance concrete and a preparation method thereof, and belongs to the technical field of novel wall materials, and the shrinkage-free aluminoferrite cement-based ultra-high performance concrete comprises the following components: an activated cementing material, mineralized aggregate, an additive, reinforced fibers and mixing water. Due to the slow release effect of the methyl cellulose coating on the composite expanding agent, precise compensation of self-constriction is achieved, and contraction deformation in the curing and using process is effectively inhibited. Due to the unique mineral composition of the aluminoferrite cement, the early strength of the concrete is sharply improved, and the production cycle of prefabricated parts is greatly shortened. The steel fibers subjected to sand blasting and pre-wrapping modification can effectively bridge microcracks in the concrete and limit crack propagation; the polycarboxylate superplasticizer disperses the modified carbon nanofibers, crack initiation is inhibited from the microscopic level, and mechanical properties such as fracture resistance and impact resistance of the joint part and the prefabricated part are remarkably improved through cooperation of the polycarboxylate superplasticizer and the modified carbon nanofibers.
Owner:TECH SUPERVISION & RES CENT FOR BUILDING MATERIALS IND

Nickel-based tungsten carbide laser cladding wear-resistant gradient coating as well as preparation method and application thereof

The invention discloses a preparation method of a nickel-based tungsten carbide laser cladding wear-resistant gradient coating, which comprises the following steps: step 1, preparing mixed powder of a transition layer, a functional layer and a repair layer; step 2, pretreating a matrix: removing oxide skin on the surface of the matrix, polishing to be smooth, and preheating the matrix to 350-500 DEG C; step 3, sequentially preparing a first functional layer, a transition layer, a second functional layer and a repair layer by adopting a laser cladding process; and 4, coating post-treatment is conducted, specifically, the surface of the repairing layer is polished to the specified thickness, and the defect-free wear-resistant gradient coating is formed. Through gradient component layered design, the functional layer adopts high tungsten carbide content to maximize wear resistance, and the transition layer relieves thermal expansion difference between the coating and a matrix, reduces interface stress and reduces crack initiation; according to the repairing layer, micro-cracks and air holes generated in the cladding process are filled through low-hardness nickel-based components, and the compactness and surface integrity of the coating are remarkably improved.
Owner:SHANGHAI TIANRUI JIANBO COMPOSITE PIPE CO LTD

Concrete crack early recognition method based on 3D point cloud

The invention relates to a 3D point cloud-based concrete crack early recognition method. The method comprises the following steps of modeling a fine curvature change generated by a concrete surface at the initial stage of a crack into a high-order local nonlinear offset function; curvature derivative tensor fitting is carried out by using the third-order neighborhood of the point so as to distinguish a real crack sign and noise disturbance; a space stress projection field of the candidate area is formed in the crack germination stage, so that early deformation cracks are identified; based on a stress field guided point cloud reconstruction mechanism, enhancing the point density of the potential crack region identified by the perturbation model by adopting a local reversible interpolation algorithm; according to the interpolation, a crack space consistency constraint graph is constructed according to the continuity and curvature gradient of a surrounding normal, and the structural integrity is improved while the original crack form is reserved; and constructing a crack region into a vector flow field form, and fitting a growth path prediction trajectory of the crack region through the minimum principal curvature direction of crack end points in the point cloud.
Owner:ZHEJIANG COLLEGE OF CONSTR

Method for evaluating crack resistance of hole body concrete

The invention provides a method for evaluating the crack resistance of tunnel body concrete, and belongs to the technical field of wind tunnels, and the method comprises the steps: uniformly arranging multiple types of sensors on the surface of a tunnel body concrete structure to form a high-density monitoring network, employing a concrete circular ring constraint test piece to establish an anti-crack reference database, and constructing a multi-working-condition temperature stress database; acquiring multi-dimensional data such as strain, temperature and acoustic emission in real time, inputting the monitoring data into a liquid adaptive neural network model to predict crack initiation probability and expansion risk, establishing a crack risk assessment function, formulating a corresponding processing strategy according to a risk coefficient range, and starting an intelligent spray maintenance system; a closed-loop control system from monitoring perception to risk early warning to active protection is formed, and the technical problem that crack initiation and expansion risks of a hole body concrete structure cannot be accurately predicted under complex working conditions is solved.
Owner:CHINA CONSTR EIGHT ENG DIV CORP LTD

Concrete anti-cracking method and system based on fiber reinforcement

The invention discloses a concrete anti-cracking method and system based on fiber reinforcement, and belongs to the technical field of concrete anti-cracking. The method comprises the following steps: acquiring real-time strain data in concrete through a distributed optical fiber sensor; analyzing the data to obtain a three-dimensional crack propagation path containing a crack initiation position, a propagation angle and a tip position; identifying the dominant development direction of the crack and a fan-shaped potential expansion interval which extends at an expansion angle by taking the tip as a vertex based on the path data; in the potential expansion interval of the to-be-poured area, a fiber distribution layer arranged in the dominant development direction is formed through directional arrangement equipment; and the fiber-reinforced anti-cracking structure is formed through vibrating and compacting treatment. According to the invention, directional blocking of fibers to crack expansion is realized, the problem of disordered expansion of cracks is effectively solved, and the anti-cracking efficiency of concrete is improved.
Owner:中煤西安设计工程有限责任公司 +1

Machine vision-based real-time monitoring system for fatigue cracking of welding seam of steel structure

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.
Owner:ZHEJIANG LIDE ENGINEERING CONSULTING CO LTD

Rock porosity adaptive modeling and blasting crack expansion calculation method based on key-type near-field dynamics

The invention provides a rock porosity adaptive modeling and blasting crack expansion calculation method based on key-type near-field dynamics, and the method comprises the steps: constructing a unified near-field dynamics model containing pore adaptive generation and blasting dynamic response; dynamic simulation of the rock blasting process is realized through pore distribution control, blasting load time history application and crack evolution judgment, and crack initiation, expansion and penetration rules can be accurately reproduced while the calculation stability is ensured. By introducing a pore adaptive discrete algorithm, the construction of rock models under different porosity conditions is automatically realized, and the initiation, expansion and penetration processes of cracks in the rock mass are accurately predicted in combination with near-field dynamics mechanical calculation under the action of an explosion load. According to the method, the heterogeneous characteristic of the rock and the discontinuous effect of the blasting load can be considered at the same time under a unified dynamic framework.
Owner:CHINA THREE GORGES UNIV

Thimble anti-fatigue strengthening method based on multi-section variable temperature treatment

The invention discloses an ejector pin anti-fatigue strengthening method based on multi-section variable-temperature treatment, and relates to the technical field of ejector pin anti-fatigue strengthening, and the ejector pin anti-fatigue strengthening method comprises the following steps: austenitizing high-temperature quenching: heating an ejector pin to an austenitizing temperature, and then carrying out zoned cooling on the ejector pin; medium-temperature tempering and thermal-state mechanical strengthening are conducted, specifically, the ejector pin is tempered at the medium-temperature tempering temperature, and thermal-state shot blasting or laser shock is conducted on the ejector pin in the heat preservation period or after heat preservation is completed; intermediate low-temperature plasma nitriding: carrying out plasma nitriding in a nitrogen-hydrogen gas environment; subzero treatment: placing the ejector pin in liquid nitrogen; and finally, low-temperature tempering and cold-state mechanical strengthening are conducted. Through multi-section temperature gradient treatment, phase change distribution control over different temperature sections is achieved, too high internal stress and brittleness generated by one-time quenching are avoided, sudden size change and hot cracks induced by phase change are prevented, a controllable surface-core hardness and toughness gradient is formed, the surface crack initiation tendency is reduced, and the surface quality is improved. And the consistency and controllability of anti-fatigue basic conditions are improved.
Owner:ZHEJIANG QITIANHUA MOLD TECHNOLOGY CO LTD

Crack resistance evaluation method and system based on concrete shrinkage rate

The invention provides an anti-cracking performance evaluation method and system based on a concrete shrinkage rate. The method comprises the following steps: firstly, collecting shrinkage rate real-time sequence data and an acoustic emission signal flow of a concrete sample in a curing process, separating a high-frequency elastic wave energy attenuation characteristic value from the acoustic emission signal flow, and carrying out space-time coupling on the high-frequency elastic wave energy attenuation characteristic value and a shrinkage rate jump point in the shrinkage rate real-time sequence data to generate a crack initiation tendency index; then obtaining a calibrated crack initiation tendency index based on an ambient temperature hysteresis effect and a temperature drift error of the calibrated crack initiation tendency index, and then outputting an anti-crack performance grade according to a grading deviation degree between a pre-designed grading parameter and a fluctuation range of the calibrated crack initiation tendency index; according to the technical scheme provided by the invention, the essential defect that a traditional method cannot correlate material characteristics with environmental response is overcome, direct quantitative mapping of material structure performance and damage evolution is also realized, and a traceable material-level basis is provided for engineering anti-crack design.
Owner:SICHUAN JIAOTOU CONSTR ENG CO LTD +2

Underground structure damage evolution evaluation method under sudden explosion load effect

The invention discloses a method for evaluating damage evolution of an underground structure under the action of a sudden explosion load, and relates to the technical field of civil engineering and engineering disaster prevention, and the method is characterized by comprising the following steps: S1, simulating the underground structure based on an explosion load, a geometric boundary and material parameters, and constructing a unified constitutive model; and S2, introducing a pressure-related strength criterion of a Dwark-Prasugrel criterion into the unified constitutive model so as to describe the influence of confining pressure on the shear strength. The technical problem to be solved by the invention is to provide the method for evaluating the damage evolution of the underground structure under the action of the burst explosion load, so that the key pain points such as pressure correlation, high strain rate effect, material random discreteness, damage softening energy consistency and the like are difficult to consider at the same time in the existing analysis method. A set of damage evolution evaluation method and implementation system which can be implemented from the material level to the structure level is established, and quantitative prediction and engineering grading judgment of the whole process of crack initiation, expansion to instability failure of the underground structure are supported.
Owner:CHINA UNIV OF MINING & TECH

Super soft austenitic stainless steel and method of making

The application discloses a super-soft austenitic stainless steel and a preparation method thereof. The super-soft austenitic stainless steel is composed of carbon C, nitrogen N, silicon Si, manganese Mn, chromium Cr, nickel Ni, copper Cu and iron Fe. The mass percentage of each component in the super-soft austenitic stainless steel is as follows: C: 0.005%-0.02%, N: 0.05%-0.2%, Si: 0.01%-0.1%, Mn: 1.5%-6.5%, Cr: 15.5%-19.6%, Ni: 7.5%-13.5%, Cu: 1.8%-5.3%, and the balance is iron. The super-soft austenitic stainless steel has the characteristics of low tensile strength and hardness, low strain-induced martensite in the bending process, low crack initiation rate and low failure fracture.
Owner:ZHEJIANG JUCHUANG STAINLESS STEEL PROD TECH CO LTD +1

Slurry valve erosion-resistant multi-layer coating with gradient function design and preparation method of slurry valve erosion-resistant multi-layer coating

The invention relates to the technical field of material science, and discloses a slurry valve erosion-resistant multi-layer coating with gradient function design and a preparation method thereof.The coating comprises a bonding layer, a gradient function layer and an erosion-resistant surface layer which are sequentially arranged from inside to outside, the bonding layer is composed of nickel-based alloy or cobalt-based alloy, the thickness of the bonding layer is 50-100 micrometers, and the thickness of the gradient function layer is 50-100 micrometers. The gradient functional layer is made of composite powder of metal and ceramic, the metal is nickel or cobalt, the ceramic is tungsten carbide or chromium carbide, and the components of the gradient functional layer are from the bonding layer side to the erosion-resistant surface layer side; the bonding layer is arranged and forms firm metallurgical bonding with the matrix, the interface stress is reduced, the basic reliability of bonding of the coating and the matrix is guaranteed, meanwhile, the gradient functional layer with the metal and ceramic volume fraction gradually changing continuously is adopted, the problem that the thermal expansion coefficients of the coating and the matrix are not matched is solved, and the service life of the coating is prolonged. And the crack initiation and expansion risk caused by internal stress concentration is reduced, so that the long-term stability of the coating structure is ensured.
Owner:YANGQUAN VALVE CO LTD

Intelligent tensile testing machine for tight-lock coupler and testing method of intelligent tensile testing machine

The invention discloses a tight-lock coupler intelligent tensile testing machine and a testing method thereof, and belongs to the technical field of tight-lock coupler test.The tight-lock coupler intelligent tensile testing machine comprises a mounting bottom plate and an electric control cabinet, and a support for supporting a tight-lock coupler to be detected is mounted on the surface of the mounting bottom plate; a tensile connecting frame for connecting the tight-lock coupler is mounted on the surface of the bottom plate on one side of the support, an integrated design of'tensile force detection and visual detection 'is innovatively adopted, mechanical parameter acquisition and visual deformation observation are combined, traditional mechanical data such as tensile force and displacement are obtained, and visual characteristics such as fine deformation and crack initiation are captured; precise synchronization of pulling force application, displacement collection and camera shooting is achieved through the synchronous controller, the real-time corresponding relation of pulling force-displacement-visual deformation is established, the problems that an existing device is single in detection dimension and poor in data relevance are solved, and the potential quality hazard checking capacity and the persuasion of a detection result are improved.
Owner:URUMQI RAILWAY BUREAU

High-reliability equal-strength design method and system for intelligent cubic press

The invention relates to the technical field of equal-strength design, and provides a high-reliability equal-strength design method and system for an intelligent cubic press, which considers structural characteristics of the cubic press, performs physical field analysis, modeling and simulation, determines deformation, temperature, stress distribution and stress concentration areas of key components, predicts structural crack initiation of the key components, and provides a high-reliability equal-strength design method and system for an intelligent cubic press. Crack propagation simulation is carried out; establishing a fatigue strength life prediction model based on deep learning and a simulation data set; constructing a fatigue strength reliability model, and establishing a mathematical association relationship among fatigue life, fatigue damage and reliability; a reliability calculation index is introduced into multi-objective optimization of the structure, a high-precision numerical solution of reliability robustness optimization design based on structure simulation is developed, and equal-strength design of the cubic press is achieved. According to the method, the optimal combination of design parameters can be obtained, the equal-strength design of parts and the whole machine structure is formed, and development of intelligent, high-precision and large-scale cubic press equipment is promoted.
Owner:ZHENGZHOU UNIVERSITY OF LIGHT INDUSTRY +3

Construction method of multi-span hole assembly type cover plate small bridge and culvert structure

The invention belongs to the technical field of highway bridge and culvert engineering, and discloses a multi-span hole assembly type cover plate small bridge and culvert structure construction method which is characterized in that side walls, middle walls and cover plates are transported to a construction site to be assembled after being prefabricated, so that site formwork erecting work is effectively reduced, the construction process is simplified, and the construction efficiency is improved; the connection strength and the structural stability are improved through a grouting method, and then the problem of insufficient grouting of a bedding method is further solved through a secondary grouting method; the pre-embedded steel bar groups of the adjacent cover plates are welded and connected, and by utilizing an equivalent load preloading pre-deformation method in advance, cast-in-place connection areas can bear more uniform stress distribution after being fixedly connected, the stress state in the service stage tends to be more balanced, the crack initiation risk is reduced, and the overall stability and durability of the structure are improved; rigid connection is formed between the adjacent cover plates and the middle wall, the risks of cover plate damage, slab staggering and reflection cracks caused by displacement or looseness of the abutted seam are reduced, and the structural safety and the service life of the bridge and culvert are guaranteed.
Owner:ZHEJIANG INST OF COMM CO LTD

Method for researching crack evolution law of fractured rock under thermal-mechanical coupling

The invention discloses a research method for a crack evolution law of fractured rock under thermal-mechanical coupling, and belongs to the technical field of rock mechanics. Aiming at the problem that most indoor tests and numerical simulation at present still lack systematic research on crack initiation, polymerization and failure behaviors of cracks in a multi-crack rock mass under the action of high temperature-stress coupling, the method comprises the following steps: defining an interaction coefficient and a thermal damage influence coefficient between the cracks on the basis of a tangential stress distribution theory around the cracks; establishing a tangential stress model sum of the inner and outer surfaces of the crack comprehensively considering the coupling effect of the two to predict a potential crack initiation position; based on a crack mode displacement decomposition method, defining a displacement ratio coefficient gamma, and quantifying a displacement field of rock material cracks; on the basis, the rock sample is subjected to mechanical test and PCF numerical simulation, and the crack evolution law of the rock sample containing the prefabricated crack under thermal-mechanical coupling is researched. Theoretical support and experimental basis can be provided for stability evaluation and safety control of deep high-temperature rock mass engineering.
Owner:JINAN UNIVERSITY

Intelligent prediction method and system for fatigue life of rusted steel plate

The invention relates to the technical field of fatigue life prediction, in particular to an intelligent prediction method and system for the fatigue life of a rusted steel plate, and the method comprises the steps: measuring the three-dimensional shape of the rusted steel plate to be measured to obtain the surface data of the rusted steel plate, and then inputting the data into a trained crack fatigue initiation life prediction model, the model comprises a crack initiation life prediction module and a stress concentration coefficient prediction module, so that the fatigue initiation life of the crack is obtained. Then corrosion detail information generated by cracks is analyzed to obtain corrosion defect characteristics, and then defects are input into the fatigue crack propagation life prediction model to obtain corresponding life. And finally, calculating the total service life of the rusted steel plate according to the fatigue initiation service life and the fatigue crack propagation service life of the crack, thereby further improving the crack prediction precision.
Owner:XI'AN UNIVERSITY OF ARCHITECTURE AND TECHNOLOGY

Welded joint fatigue weak area evaluation method based on crystal plasticity

The invention discloses a method for evaluating a fatigue weak area of a welded joint based on crystal plasticity, which aims at the problem of fatigue failure of the welded joint caused by complex microstructures such as grain orientation difference and uneven grain size distribution, establishes a quantitative correlation model of grain orientation and size evolution through CPFEM, and combines a macro-micro cross-scale analysis method to evaluate the fatigue weak area of the welded joint. And precise prediction of local stress concentration and crack initiation behaviors of the welding joint under a real fatigue load working condition is realized, so that scientific evaluation of a fatigue weak region is completed. According to the method, an innovative framework of fatigue weak area evaluation is constructed through load working condition reduction and grain characteristic multi-scale coupling, so that excessive simplification of a traditional method on real load conditions is made up, the limitation that a traditional model is difficult to couple a microstructure and a real load is overcome, and the fatigue weakening quantization precision is remarkably improved; and a high-precision analysis technology is provided for anti-fatigue design, process optimization and service life evaluation of the engineering welding structure.
Owner:EAST CHINA UNIV OF SCI & TECH

High-wear-resistance hard alloy CVD (Chemical Vapor Deposition) coated cutting tool and preparation method thereof

The invention discloses a high-wear-resistance hard alloy CVD (Chemical Vapor Deposition) coated cutting tool and a preparation method thereof, WC-Co (4-8) Ti (1-5) Ta (1-5) Nb (0.2-2) Cr (0.2-2) Fe (0.2-2) Al (0.2-2) is used as a blade substrate, TiN, TiCN, Al2O3 and a surface TiN coating are deposited firstly, and then the coated blade is subjected to subzero treatment and tempering treatment. According to the method, through subzero treatment between the base body and the coating, the compressive stress is introduced into the coating or an interface by utilizing the difference of the extremely low temperature shrinkage rates of the coating and the base body, the tensile stress caused by the compressive stress neutralization deposition is utilized, and the uniform distribution of nanoscale carbide precipitates is promoted by utilizing a proper tempering process; and the cold brittleness phenomenon caused by subzero treatment and the generated high residual compressive stress are avoided, and the abrasion resistance and the anti-stripping capacity of the base body are further improved. According to the method, the driving effect of residual tensile stress in the CVD coating on crack initiation is reduced, the crack density is greatly reduced, the mechanical property of a hard alloy matrix and the stress state of the coating are synergistically improved, and the mechanical property of the cutter is enhanced.
Owner:OKE PRECISION CUTTING TOOLS CO LTD

Consequence simulation method based on water electrolysis hydrogen production

The invention discloses a consequence simulation method based on water electrolysis hydrogen production, which comprises the following steps: constructing a multi-physical field coupling simulation model comprising an electric field, a thermal field, a flow field and a stress field, and setting and calibrating a geometric structure, physical property parameters, boundary conditions and a numerical strategy to obtain base field distribution of an electrode system. A bubble dynamics whole-process model is introduced, nucleation, diffusion growth and separation of bubbles are simulated, gas-liquid two-phase dynamic feedback is achieved through a volume fraction method, bubble interface force and a thermal expansion effect are coupled, and micro-crack formation of the electrode is judged by utilizing a stress criterion and a crack initiation threshold. And carrying out curing treatment on crack evolution by adopting a virtual crack unit or a phase field method. A crack propagation process is simulated in combination with a Miner criterion and a Paris law, an acoustic source item is introduced, an acoustic wave equation is solved, and the effects of full-link prediction, early warning, reliability evaluation and life optimization of electrode damage and hydrogen production performance are achieved in the operation process of the water electrolysis hydrogen production system.
Owner:SHANGHAI GELUE SOFTWARE TECH CO LTD

Device for testing peel strength of composite film

The invention relates to the technical field of composite film strength detection, and discloses a composite film peel strength testing device which comprises a testing platform, two pulling sliding plates slidably mounted in the two extending parts respectively and capable of being synchronously and mutually close to or away from each other for adjustment, and the two pulling sliding plates are arranged on the testing platform. The opposite ends of the two pulling sliding plates are each provided with a clamp used for clamping a single-layer film of a composite film separation section. The clamping assembly is arranged in the test platform and is used for clamping and limiting the fitting section of the composite membrane and enabling the separation section and the fitting section of the composite membrane to form a Y-shaped state; and two groups of test assemblies. Through the Y-shaped constant-angle stripping design, the stripping surface of the composite film is uniquely locked, the stripping angle is kept unchanged in the whole testing process, and the effects that stripping cracks are stably limited to a specified unique interface, crack initiation is controllable and deviation is avoided are achieved.
Owner:YANCHENG YOUBOTE NEW MATERIAL CO LTD

Blade root fatigue load prediction and inversion system of offshore wind turbine

The invention relates to a blade root fatigue load prediction and inversion system for an offshore wind turbine, and the system comprises a data collection assembly which obtains a circumferential strain gradient, and synchronously collects wave spectrum energy distribution, leading edge erosion degree and three-dimensional wind field data to establish a joint input spectrum; the hybrid calculation component is used for generating an adversarial network, reconstructing strain distribution of a bolt hole in a non-degraded state, and comparing a circumferential strain gradient to obtain an abnormal blade root dangerous point; and the control output assembly is used for superposing the damage accumulation cloud picture of the blade root dangerous point, displaying the fatigue life consumption rate and calling an equivalent load spectrum duration curve, and generating an independent variable pitch angle instruction according to the combination of asymmetric load distribution and the combined input spectrum. According to the method, quantitative identification and positioning of early-stage micro-damage can be realized, the hysteresis limitation of traditional threshold alarm is broken through, complex fatigue analysis is converted into engineering interpretable indexes, and a fault backtracking technical support is provided; load active compensation control is achieved through an independent variable pitch instruction, and fatigue crack initiation and expansion are effectively restrained.
Owner:CGN WIND POWER CO LTD +1