458 results about "Fatigue cracking" patented technology

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 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 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 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 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 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 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 application discloses a brake interface wear and fatigue crack prediction method based on complete thermal-mechanical coupling, comprising the following steps: S1, establishing a finite element model, and discretizing total analysis time into multiple time periods; S2, starting finite element analysis, and calculating interface node contact pressure and node slip rate; S3, performing transient thermal-mechanical coupling analysis; S4, calculating node wear depth and wear direction, and updating grid information by using ALE technology; S5, judging whether the interface contact state is stable convergence; S6, ending analysis, unloading brake load, and obtaining brake disc residual stress; and S7, presetting a crack at the maximum residual stress, simulating crack propagation behavior, calculating stress intensity factor and brake disc fatigue life. The application can simulate tribological behaviors such as contact stress, temperature and wear, and realizes brake disc fatigue life prediction by taking residual stress after the thermal-mechanical coupling process as load input.

The invention relates to the technical field of glass product manufacturing, in particular to a production parameter optimization method and system for a lightweight glass bottle and a medium. The method comprises the following steps: acquiring a glass bottle structure drawing, and identifying a bottle body structure and a bottle bottom structure; constructing a lightweight glass bottle model according to the bottle body structure and the bottle bottom structure; performing impact load simulation according to the lightweight glass bottle model to obtain impact load data; identifying a structure weak point based on the impact load data; performing fatigue crack evolution according to the structure weak points to generate glass crack data; identifying a crack shape based on the glass crack data to obtain zigzag glass crack data and radial glass crack data; and performing grain interface detection based on the zigzag glass crack data to obtain grain interface data. Based on a glass product manufacturing technology, the strength retention rate and the parameter adjustment precision rate in the glass bottle lightweight production process are improved.

The invention belongs to the technical field of bolt life monitoring, and discloses a device and a method for monitoring a high-strength bolt in a space grid structure based on acoustic emission, and the device is characterized in that an acoustic emission probe is arranged on the surface of a nut of the high-strength bolt; the acoustic emission probe is connected with the charge adapter; the charge adapter is connected with the high-frequency signal acquisition instrument; the high-frequency signal acquisition instrument is connected with the computer; the high-strength bolts generate fatigue cracks under the action of circulating and reciprocating loads; the acoustic emission probe transmits the acoustic emission process before fatigue fracture of the high-strength bolt to the computer, the computer draws a fatigue curve of the high-strength bolt, and online prediction is conducted on the whole life of the bolt, accurate early warning can be conducted before fracture, structural safety accidents are avoided, and the method is suitable for bridges, large-span buildings and other scenes with the high requirement for bolt strength; and long-term safety of infrastructures is guaranteed.

The invention provides a simulation method for a microscopic fatigue cracking behavior of a semi-flexible pavement. The simulation method comprises the following steps: step 1, forming a large-gap matrix asphalt mixture test piece; 2, a cement grouting material is poured; step 3, acquiring an SFP mesoscopic image; step 4, obtaining a binary image of the SFP; 5, constructing a pavement structure model; 6, determining the thickness and the thickness proportion; step 7, constructing a mesoscopic finite element model; 8, constructing a pavement structure finite element model containing the SFP microstructure; step 9, determining CZM model parameters; step 10, inserting a CZM unit; step 11, setting CZM model parameters; 12, simulating a traffic load; and step 13, simulating the fatigue cracking behavior of the SFP in the pavement structure, and quantifying the damage and the change process thereof. According to the method, the normal and tangential CZM parameters and the difference thereof in the CZM model are considered at the same time, the CZM parameters of the two-phase cementing materials with different thicknesses and thickness ratios are determined through the self-designed pull-out test and direct shear test, and the fatigue cracking behavior of the SFP can be simulated and analyzed more accurately.

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

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.

The invention discloses a thermal mechanical fatigue crack growth rate testing method based on rigidity and a crack tip strain field. The method comprises the following steps: firstly, establishing a relation function between normalized crack length and normalized rigidity through finite element calculation; secondly, performing DIC speckle preparation for observing crack propagation and analyzing a strain field; then carrying out a thermal mechanical fatigue test, calculating the crack length based on a rigidity change result of the test, drawing an a-N relation curve in combination with a DIC synchronous observation result, and carrying out comparative analysis; and finally, calculating the crack growth rate through a three-point moving average secant method, and analyzing and determining the size of a crack tip plastic zone according to a DIC strain field, so as to accurately test the crack growth rate. The fatigue crack growth behavior under the thermal-mechanical coupling effect can be effectively tested, the thermal mechanical fatigue crack growth rate is accurately obtained by combining a crack tip strain field measurement method, and test data support is provided for damage tolerance design and structural integrity evaluation of high-temperature pressure-bearing equipment.

The invention discloses a method for improving the rotating bending fatigue strength of an AlCoCrFeNi 2.1 eutectic high-entropy alloy, and belongs to the technical field of alloys. According to the method, the AlCoCrFeNi 2.1 eutectic high-entropy alloy is treated by utilizing an ultrasonic surface rolling process (USRP), so that the density of surface defects and holes of the AlCoCrFeNi 2.1 eutectic high-entropy alloy is effectively reduced, and the rotating bending fatigue strength of the AlCoCrFeNi 2.1 eutectic high-entropy alloy is improved. And meanwhile, the surface roughness is reduced, the surface structure morphology is changed, the crack propagation path is prolonged, and finally the purpose of improving the fatigue performance of the AlCoCrFeNi 2.1 eutectic high-entropy alloy is achieved. According to the method, the surface structure of the AlCoCrFeNi 2.1 eutectic high-entropy alloy can generate residual compressive stress under the action of high-frequency vibration and static-load rolling of the USRP, so that the initiation time of fatigue cracks is effectively prolonged, and the fatigue performance of the AlCoCrFeNi 2.1 eutectic high-entropy alloy is enhanced.

The invention relates to the technical field of image segmentation, provides an image segmentation method and system for a cantilever system of a high-speed rail overhead line system supporting device, and solves the problems that defects in a metal part cannot be detected, and the defect recognition precision is low under high-frequency vibration noise interference. The method comprises the following steps: scanning a metal part of the cantilever system to generate a three-dimensional image, and collecting a stress wave signal of the surface of the metal part under the action of a dynamic load; based on the cyclic load parameter of the metal part, extracting the spectrum characteristic of the stress wave signal, and determining the energy distribution characteristic of the bolt joint by combining the geometric structure parameter of the bolt joint of the metal part; and fusing the three-dimensional image, the energy distribution characteristics, the temperature rise abnormal region and the electric field intensity distribution to generate a multi-source data set, and generating respective segmentation results of the fatigue crack and the insulation aging defect of the metal part in combination with the cyclic load parameters. According to the invention, high-precision collaborative segmentation of metal fatigue cracks and insulation aging defects of the cantilever system is realized.

The invention relates to a large-span bridge steel box girder fatigue damage local and overall collaborative evaluation method and system. Acquiring strain responses of a reference section and a test section of the steel box girder before and during traffic service based on a dynamic load test, defining and calculating a strain ratio and a rigidity ratio of each monitoring point, and diagnosing local crack positions of the steel box girder by utilizing statistical characteristics of the strain ratios; establishing a mapping relation between the rigidity ratio and local damage such as crack length, expansion rate and tip position, and proposing a fatigue crack safety coefficient to realize collaborative quantitative characterization of local damage and overall safety; and constructing a genetic algorithm to optimize a support vector machine model, and developing a real-time evaluation system which takes the real bridge strain response as input and takes the local crack damage type and the overall safety level of the steel box girder as output. The defect that local damage diagnosis and overall performance evaluation of the steel box girder are mutually separated in a traditional method is overcome, and real-time diagnosis and safety evaluation of fatigue damage of the large-span bridge can be synchronously achieved.

The invention discloses a railway vehicle welding structure fatigue detection system, which comprises a welding structure fatigue simulation subsystem for acquiring data of a welding structure, fitting an S-N curve and performing fatigue life simulation calculation of the welding structure; the visual fault detection subsystem is used for carrying out image acquisition on the welding structure and carrying out fatigue crack identification on the acquired image data; the disassembly detection subsystem is used for recording image data and analysis data of the welding structure, and comparing and analyzing the image data with the image data of the visual fault detection subsystem to form a crack change detection result; the cooperative working platform is used for transmitting the detection data of the three subsystems, integrating the detection data of the three subsystems, predicting the fatigue state of the welding structure and outputting the remaining life; simulation calculation in the design stage is combined with actual detection data of the visual fault detection subsystem and the disassembly detection subsystem, and the accuracy of the welding structure fatigue crack simulation subsystem can be continuously improved along with accumulation of the detection data.

The utility model relates to a reinforcing rib welding seam reinforcing structure of an orthotropic steel bridge deck slab, belongs to the technical field of bridge engineering, fully utilizes the characteristics of high strength, corrosion resistance, light weight and the like of an FRP (Fiber Reinforced Plastic) material, and has the characteristics of simple structural form and light weight. The FRP profiles are adhered to the two sides of the weld joints of the stiffening ribs of the orthotropic steel bridge deck, and the stiffening ribs of the weld joints which may generate fatigue cracks and the steel bridge deck are connected into a whole through the FRP profiles, so that the overall bearing capacity and the anti-fatigue performance of structural members are enhanced, and the repair reliability is guaranteed. And meanwhile, the method has the characteristics of easiness in construction and short construction period, and the influence of repairing and reinforcing operation on road traffic operation is reduced.

The invention relates to the technical field of metal material surface engineering and equipment remanufacturing, in particular to an early acoustic emission diagnosis and laser cladding repair method for thermal fatigue cracks in a mold service process, which comprises the following steps: S1, synchronously acquiring and preprocessing multi-source heterogeneous data; stress wave signals are collected in real time through a broadband acoustic emission sensor array permanently integrated on the surface of a mold cavity, the frequency response range of the sensor is 100 kHz to 1 MHz, and the sensitivity is not lower than 95 dB. According to the method, accurate identification and positioning can be realized at the initial stage of crack initiation through multi-modal sensing fusion and a deep learning algorithm, the diagnosis accuracy is remarkably higher than that of a traditional offline detection method, and precious time is won for subsequent repair.

The invention relates to a method, a device, equipment and a medium for predicting the fatigue crack life of an offshore well drilling rack, and is applied to the technical field of engineering equipment life prediction. Analyzing the monitoring data and the video data to determine a crack condition; acquiring historical life information, current task information and current environment data; and analyzing the crack condition, the historical life information, the current task information and the current environment data to obtain a life prediction condition. The method has the effect of improving the accuracy of predicting the crack propagation life of the offshore well drilling rack.

This utility model relates to the field of rail transit technology, and in particular to a spring plate for an obstacle detection device, comprising a horizontal plate, wherein one end of the horizontal plate is bent downward to form a bogie support connection part, and the other end is bent downward to form a crossbeam toothed plate connection part, and the bending areas at both ends of the horizontal plate are arc-shaped; the thickness of the crossbeam toothed plate connection part is less than the thickness of the horizontal plate, and the thickness of the arc-shaped bending area between the two gradually decreases along a first preset direction. While satisfying the original performance, this utility model adopts a gradually changing wall thickness structural design, which enhances the stability of the spring plate under high-frequency, high-amplitude random vibration environments, reduces stress concentration in the bolt hole area, and delays the generation and propagation of fatigue cracks, thereby solving the problem of early fracture of spring plates due to stress accumulation in the prior art.

The application discloses a high-performance motor rotor core, comprising rotor laminations, wherein a plurality of magnetic steel slot groups are arranged on the rotor laminations in a circumferential direction; the application has simple structure and reasonable design; stress reduction structures with central symmetry characteristics are arranged to effectively guide and release main radial stress in the magnetic bridge area, optimize stress distribution, avoid fatigue cracks caused by local stress concentration, improve fatigue life and structural safety margin of the magnetic bridge, and improve NVH performance, reduce electromagnetic harmonics, and improve stability and quietness of motor operation; in addition, the overall magnetic steel slot layout is optimized to realize reasonable reduction of material use and lightweight design of the rotor core, and improve power density and dynamic response capability under the premise of guaranteeing electromagnetic performance.

The utility model discloses a kind of CNG pipe bundle type container shockproof fixed connection structure, it is related to pipe bundle type container technical field, including pipe bundle type container body, the lower surface inside the pipe bundle type container body is fixedly connected with two first fixed seat, the top of two the first fixed seat is evenly provided with second fixed seat, the top of two the second fixed seat is fixedly connected with third fixed seat, the upper surface of two the first fixed seat, the upper and lower two surfaces of two the second fixed seat and the lower surface of two third fixed seat are all set with sliding slot, the inside of each sliding slot is slidably provided with arc clamping block. The utility model passes through the sliding of piston plate in sealing cavity, utilizes the viscous damping force generated by the flow of hydraulic oil through fine hole, cooperates with the elastic reset of spring, can effectively absorb the impact force such as jolt, sudden braking in vehicle driving, to significantly reduce the fatigue crack and sealing element failure risk of CNG gas collecting bottle.

This invention discloses a method and system for real-time stress monitoring during laser additive repair of fatigue long cracks in turbine casings. The method includes: preparing a high-temperature resistant speckle pattern in the pre-treated repair area; simultaneously acquiring a sequence of speckle images and a sequence of temperature field images during the laser repair process; calculating the strain field based on digital image correlation and calculating the real-time stress evolution using thermo-elastic-plastic stress-strain increment theory. The real-time stress value is compared with a dynamic threshold set based on the material's yield strength, and the laser power or scanning speed is controlled based on the feedback of the result to achieve closed-loop control of the repair stress. This invention achieves high-precision real-time online monitoring of stress under extreme repair environments, providing a basis for optimizing and intelligently controlling repair process parameters, effectively suppressing residual stress and the risk of secondary cracks, and significantly improving the repair quality and reliability of turbine casings.

The application discloses a kind of based on mould casting parting surface with intelligent polishing device and its operating method, it is related to mould polishing technical field, including polishing main body, the inner wall of polishing main body is provided with roller conveyor, and the top of roller conveyor is placed with mould, and one end of polishing main body top is fixedly connected with support plate, one side of support plate outer wall is fixedly connected with electric telescopic table, and the output end of electric telescopic table is threadedly connected with support table.The application is provided with a plurality of grooves in the bottom of grinding ring, so that the air below guide block is discharged through the fitting surface of grinding ring and mould under the traction of groove, further solve the problem that the heat generated by traditional mould casting parting surface with intelligent polishing device cannot be quickly dispersed during use, resulting in surface mould expansion due to heat, inner layer mould constraint expansion, thereby generating tensile stress, and heat fatigue crack can be caused by reciprocating, thereby exacerbating mould deformation.

The invention discloses a welding process of a high-strength onboard load training device, which adopts a structural combination of a plurality of layers of steel plates and a high-ductility alloy connecting piece, and utilizes a composite welding device consisting of a welding head, a gas generating ring, a tempering heating ring and a slow cooling gas curtain ring which are coaxially arranged. The synergistic effect of an electric arc heat source and a laser heat source can be achieved in the welding process, a deep penetration weld joint is formed, and sufficient metallurgical bonding of the multi-layer steel plate and an alloy connecting piece is ensured. And in cooperation with annular protective gas, local tempering and slow cooling control, the welding seam structure can be effectively improved, the residual stress can be reduced, cold cracks and fatigue cracks are prevented, and therefore the strength and stability of a welding joint are remarkably improved.

The application belongs to the technical field of cement soil preparation, and particularly relates to a composite cement soil prepared from seawater, nano-silicon dioxide and polyvinyl alcohol fiber and a preparation method thereof, which comprises 63-70% of dry soil powder, 9-10% of Portland cement, 1.8-2.2% of nano-silicon dioxide, 0.6-1.2% of polyvinyl alcohol fiber, 0.2% of dispersant and 16.4-25.4% of seawater. The composite cement soil can not only significantly reduce the dependence on fresh water resources, but also effectively solve the problems of seawater corrosion and deterioration caused by fatigue cracks due to long-term cyclic loading, thereby significantly improving the mechanical strength of the cement soil foundation and prolonging the service life of the cement soil foundation in the coastal environment, and the composite cement soil also has high economic benefits. The synergistic effect of the nano-silicon dioxide and the polyvinyl alcohol fiber significantly enhances the mechanical properties, crack resistance and seawater corrosion resistance of the cement soil, and effectively inhibits the brittle failure of the cement soil, so that the cement soil can be stably applied in the coastal soft soil foundation reinforcement engineering for a long time.

The coil spring with the reinforcing pieces comprises a coil spring body, the coil spring body comprises elastic reeds extending in the spiral direction, an elastic inner side end and an elastic outer side end, and an included angle is formed between the elastic inner side end and the elastic reed corresponding to the elastic inner side end to form a bent section; the reinforcing sheet structure comprises a reinforcing sheet body extending in the spiral direction, a reinforcing inner side end and a reinforcing outer side end, and an included angle is formed between the reinforcing inner side end and the reinforcing sheet body corresponding to the reinforcing inner side end to form a first limiting space; the reinforcing piece body is wound by at least one circle, the reinforcing outer side end passes through the reinforcing inner side end, and a second limiting space is formed by a gap between every two adjacent circles of reinforcing piece bodies. According to the coil spring with the reinforcing piece, the reinforcing piece structure is arranged on the inner coil section of the coil spring, stress generated in the winding and releasing process of the elastic reed is dispersed to the reinforcing piece body of the outer ring, fatigue cracks are prevented from being generated, and the service life of the coil spring is prolonged.