12 results about "Crack size" patented technology

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 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.

This application discloses an in-situ non-destructive method for repairing and reinforcing fatigue cracks in steel structures based on laser technology, relating to the field of steel structure building technology. The method includes the following steps: initial flaw detection of the area to be repaired in the steel structure to obtain the crack size of the fatigue crack; cleaning the area to be laser-repaired and reinforced; scanning and repairing along the crack trajectory using laser remelting technology to allow the fatigue crack to heal naturally; secondary flaw detection of the remelted repair area after laser remelting; if the test is qualified, the repair process is completed; if the test is unqualified, the residual crack depth is obtained, and the following steps are continued; reinforcing auxiliary materials are printed on the surface of the steel structure using laser cladding technology to form a cladding layer covering the remelted repair area; a residual compressive stress layer is introduced onto the surface of the cladding layer. This application eliminates the need for beveling and milling of the original steel structure, enabling direct repair of fatigue cracks, and also allows for the addition of external reinforcing auxiliary materials to effectively integrate with the original steel structure to achieve the reinforcement purpose.

This invention relates to the field of metallurgical lifting equipment testing technology, specifically a method for predicting the fatigue crack propagation life of metal structures in metallurgical cranes. The method includes: collecting structural stress spectrum, strain monitoring time-series data of stress concentration areas, lifting operation spectrum, and temperature and humidity data under service conditions; constructing an initial crack parameter model; calculating the stress intensity factor variation spectrum, including the amplitude of the stress intensity factor at the crack tip corresponding to each load cycle; calculating the crack propagation increment per cycle and accumulating the crack size evolution data; setting a critical crack propagation size threshold based on structural integrity assessment criteria; and predicting the fatigue crack propagation life by comparing the evolution data with the threshold. This method refines the calculation dimensions of the stress intensity factor, restores the dynamic evolution process of crack size, closely matches the actual service load characteristics of metallurgical cranes, and optimizes the accuracy of crack propagation life prediction.

This application discloses a method for repairing concrete foundations of substations, including the following steps: drilling, pile placement, pouring, protection, and curing. The drilling step involves creating a repair hole at the crack in the concrete foundation of the substation, with the hole size larger than the crack size. The pile placement step involves cleaning the inside and surrounding area of ​​the repair hole, inserting a pile into the hole, and positioning the pile to create gaps between the pile and the inner wall of the hole. The pouring step involves injecting filling grout into the repair hole to fully fill the gaps. The protection step involves laying a protective cloth over the repair hole, filling the gaps between the cloth and the concrete foundation, as well as between the cloth and the pile, with filling grout. The curing step involves curing the repaired area. This method for repairing concrete foundations of substations offers fast repair speed, high repair strength, and good corrosion resistance.

The present application belongs to the technical field of service structure safety evaluation, and in particular to a creep life evaluation method for cracks in the heat affected zone of a welded structure, comprising the following steps: step one, determining the material parameters of the welded structure; step two, constructing a finite element model of the heat affected zone of the welded joint containing different lengths of initial cracks; step three, determining the boundary conditions of the welded structure; step four, simulating the creep damage, determining the maximum creep damage position of each crack front and the creep life; and step five, constructing a correlation between crack size and corresponding creep life. The creep life evaluation method for cracks in the heat affected zone of a welded structure simulates the creep damage evolution process of the welded structure under different initial crack lengths, constructs a quantitative functional relationship between crack length and creep life, and uses this relationship to predict the creep life of the welded structure by only obtaining the crack length in the structure, significantly improving the engineering applicability and efficiency of life evaluation.

The invention discloses a pressure pipeline inner surface crack risk assessment method based on extended finite elements and stress triaxality, and aims to solve the problems that an existing method is insufficient in precision and ignores a coupling effect, and comparison files are limited to extreme working conditions. The method comprises the following steps: establishing and verifying an XFEM basic model, constructing a pipeline XFEM model containing inner surface cracks, revealing a crack size-angle coupling rule and identifying a critical angle of 8-12 degrees, predicting crack propagation based on stress triaxial degree, and carrying out risk grading and detection priority ranking in combination with the coupling rule. According to the method, the size-angle coupling effect is innovatively quantified, the stress three-axis degree is upgraded into an independent extension prediction tool, a complete engineering closed loop is formed, the evaluation error is smaller than or equal to 10%, the method is suitable for conventional operation and maintenance of 09MnNiDR low-temperature steel pipelines and the like, an RBI plan can be directly optimized, and the practicability and the universality are remarkably superior to those of a simulation technology optimization guiding scheme of a comparison file.

The application discloses a kind of soft material multi-mechanical parameter measuring device and method, belong to material parameter test technical field.The device includes the loading platform of placing material, for being punctured to soft material puncture component, for detecting the camera of soft material and puncture component contact surface topography, controller and include the data processor of processing soft material puncture force-displacement data, force-displacement data and the crack size of camera shooting are introduced into data processor, data processor extracts the characteristic value of each stage in force-displacement curve, after curve feature and crack size value are input into the multi-fidelity neural network in data processor pre-trained by experimental data and finite element data, obtain the multiple mechanical parameters of the soft material to be measured.The whole test device structure is simple, experimental cost is low, experimental processing is simple, and it is easy to promote, and has the advantage that only through single puncture experimental data obtains the multiple mechanical parameters of the soft material to be measured.

The present application relates to a kind of road surface evaluation indexes, more particularly to a kind of road asphalt surface crack evaluation method based on nondestructive testing technology.The steps include determining the size of detection section, establishing various crack sizes by detection: the upper surface crack condition index, middle surface crack condition index, lower surface crack condition index and asphalt surface overall crack condition index are obtained by calculation in the detection section, and the indexes are evaluated according to the road asphalt surface crack classification evaluation table.The present application is based on the nondestructive testing technology of pavement, which makes up for the problem that the existing evaluation index only evaluates the surface morphology of open crack, comprehensively considers the influence of all types of cracks on the service performance of pavement, calculates the crack condition index of upper surface, middle surface and lower surface respectively, and calculates the overall crack condition index, which is more representative and improves the pertinence and scientificity of maintenance and repair measures.

The present application relates to the technical field of metallurgical crane detection, in particular to a metallurgical crane metal structure fatigue crack propagation life prediction method, comprising: collecting structure stress spectrum, stress concentration area strain monitoring time series data, hoisting operation spectrum and temperature and humidity data under service environment, constructing initial crack parameter model, calculating stress intensity factor change spectrum containing crack tip stress intensity factor amplitude corresponding to each load cycle, calculating single cycle crack propagation increment and accumulating to obtain crack size evolution data, setting crack propagation critical size threshold value combined with structure integrity evaluation criterion, and predicting fatigue crack propagation life by comparing evolution data with threshold value. The method refines the stress intensity factor calculation dimension, restores the crack size dynamic evolution process, fits the actual service load characteristics of the metallurgical crane, and optimizes the accuracy of the crack propagation life prediction.

The application relates to the technical field of water conservancy and environmental geology, and particularly discloses a measuring device for cracks in water conservancy and environmental geology, which comprises a support, a plurality of sliding blocks connected to the support in a sliding mode, an extender arranged on the sliding blocks, an installation plate fixedly connected to the extensible end of the extender, and a flexible plug rod assembly arranged on the lower side of the installation plate and capable of being inserted into cracks in the water conservancy and environmental geology layer. The measuring device for cracks in water conservancy and environmental geology provided by the application injects silica gel solution into the cracks, forms crack filling models after the silica gel solution is solidified, takes out the crack filling models from the cracks, measures the sizes of the crack filling models, and thus realizes the measurement of the cracks, so that the crack size measurement is more intuitive and accurate.