17 results about "Extended finite element method" patented technology

A numerical simulation method for the integrity of cement sheath systems in oil and gas wells under alternating temperature and pressure is characterized by the use of extended finite element method (XFEM), concrete damage plasticity model theory, Cohesive element method, and bilinear traction separation criterion, based on elastoplastic theory and plastic damage theory. This method can simulate not only the failure process of the cement sheath-casing interface under alternating temperature and pressure and characterize the mechanical behavior of interface failure, but also the failure process of the cement sheath itself and characterize its mechanical behavior. By comprehensively analyzing the failure behavior of the cement sheath system integrity in oil and gas wells, this method enables a realistic evaluation, prediction, and diagnosis of the integrity of the casing-cement sheath-casing assembly system under alternating temperature and pressure, which helps optimize cement slurry systems, improve cementing quality, and prevent cement sheath integrity failure. This invention is applicable to the field of oil and gas drilling and production engineering technology.

The invention relates to a safety assessment method for pressure-bearing special equipment with crack defects based on health monitoring and digital twinning. Various sensors are installed at key parts of the equipment to collect running state data in real time, a parameterized digital reconstruction technology is adopted to establish high-precision twin bodies of the equipment, and stress distribution and crack propagation trend of the structure are automatically simulated and analyzed by means of cloud computing. A two-stage Bayesian optimization algorithm is innovatively used to realize self-correction of simulation result errors, and adaptive accurate mapping of a digital model to physical equipment is realized. And in a crack defect-containing area, an instability critical dimension prediction model is constructed based on an extended finite element method and a failure evaluation diagram technology, and the crack instability critical dimension is dynamically calculated. According to the invention, real-time, efficient and automatic safety assessment and early warning can be carried out on pressure-bearing special equipment, and scientific data support and decision basis are provided for safe operation and maintenance of the equipment.

The present application belongs to the technical field of wind power generation, and specifically relates to a wind power tower material crack propagation prediction method and system, which is suitable for fatigue life evaluation of large supporting structures in the wind energy industry. The method comprises: deploying a multi-source heterogeneous sensor network to collect strain, acoustic emission and environmental load data; constructing a digital twin high-fidelity finite element submodel to obtain a dynamic stress intensity factor; constructing a deep neural network, embedding the Paris law of fracture mechanics in the form of residual into the loss function to form a physical information neural network, and realizing crack propagation rate prediction; using the extended finite element method combined with the level set function and the maximum circumferential stress criterion to dynamically track the three-dimensional space expansion path of the crack; combining Monte Carlo simulation and recursive Bayesian update to evaluate the remaining life and trigger graded early warning. The present application solves the problems of insufficient fusion of physical mechanisms and data-driven in the prior art, low prediction accuracy under small samples, and lack of crack space path tracking.

The invention discloses a thermal barrier coating surface layer cracking failure probability analysis method and system, and relates to the technical field of data processing, the method comprises the following steps: establishing a three-dimensional finite element model of a thermal barrier coating, using an extended finite element method to simulate thermal stress and crack propagation behaviors under thermal cycle loading for the three-dimensional finite element model under thermal cycle loading conditions, and calculating the thermal barrier coating surface layer cracking failure probability. And obtaining a crack propagation path sequence set, carrying out state transition trend feature analysis, constructing a state transition trend feature set to carry out crack development prediction, and carrying out failure probability judgment through a crack tip critical J integral value to obtain a surface layer crack failure probability analysis result. According to the method, the technical problems that an existing method cannot accurately simulate the crack propagation process and the influence of the crack propagation process on coating failure, and the failure analysis precision is low are solved, and the technical effects that high-precision simulation and failure probability quantification of crack propagation behaviors are achieved through the propagation finite element method, complex working conditions are effectively coped with, and the failure analysis precision is improved are achieved.

The invention relates to a concrete skewback segment crack simulation analysis method, and belongs to the field of concrete construction. According to the technical scheme, the concrete skewback segment crack simulation analysis method comprises the following steps that S1, simulation analysis basic conditions are determined, specifically, concrete damage parameters are set, and finite element software is selected; s2, constructing a concrete skewback segment simulation model by adopting an extended finite element method, defining a level set function to characterize a crack interface through a level set method, and constructing a displacement function by adopting a discontinuous shape function; s3, setting a concrete crack initiation criterion and a concrete crack propagation direction criterion; and S4, anti-cracking simulation analysis is conducted on the construction stage and the operation stage of the skewback section, and the cracking state and stress field distribution of skewback section concrete are obtained. According to the method, the anti-cracking performance under the load effect in the operation stage is evaluated, the whole-stage cracking state and the stress field distribution rule are output, a whole-cycle data support is provided for engineering practice, and the problem that single-stage analysis and evaluation are one-sided in the traditional technology is solved.

The invention relates to a construction parameter optimization method and device for roof water jet slotting fracturing. The method comprises the following steps: acquiring a geometric model and a fluid-solid coupling model of drilling, slotting and fracturing; generating a plurality of groups of construction parameters for roof water jet slotting fracturing by utilizing an orthogonal design method; for each group of construction parameters, updating a geometric model based on the construction parameters, inputting the construction parameters into a fluid-solid coupling model, and carrying out numerical solution on the fluid-solid coupling model by adopting an extended finite element method based on the updated geometric model, so as to obtain extended path parameters and geometric parameters of cracks generated under the action of prefabricated slotting hydraulic fracturing; calculating fracturing pressure relief effect evaluation index values corresponding to each group of construction parameters based on the extension path parameters and the geometric parameters; and determining a target construction parameter based on the fracturing pressure relief effect evaluation index value corresponding to each group of construction parameters. According to the scheme, the water jet slotting fracturing top-cutting pressure relief effect is improved.

This invention relates to the field of materials testing technology and discloses a simulation method for coating performance based on high and low temperature cycling and prestress loading. By acquiring measured operating data of pipes or components, a composite geometric model of the coating substrate containing microporous structures is constructed. Surface roughness and interface curvature characteristics are quantified using reverse engineering. A dynamic temperature-pressure coupling equation is generated based on the thermal expansion effect of high-pressure media. The microporous optical load is converted into an equivalent heat flux density using a ray tracing algorithm. The transient boundary conditions of the temperature and stress fields are correlated. The crack initiation path is simulated using the extended finite element method. The lifetime decay curve is predicted using the Paris formula. Material parameters are dynamically corrected based on experimental data to generate a multi-parameter collaborative optimization model. This invention solves the problems of distorted interface stress assessment and lifetime prediction bias under composite loading, providing multi-physics collaborative simulation support for optimizing the compressive strength performance of coatings.

The invention provides an offshore wind turbine fatigue crack initiation position and orientation prediction method, system and device. The method comprises the following steps: establishing a corresponding finite element model according to geometric features of a to-be-analyzed structure; obtaining sea condition parameters of the to-be-analyzed structure, and performing implicit stress analysis on the finite element model based on the sea condition parameters to obtain stress and strain values at the centroid of each unit in the finite element model; embedding the cohesion model into an extended finite element method framework, and calculating stress and strain values at the centroid of each unit based on a fatigue crack initiation criterion of the cohesion model so as to output a dimensionless damage index of each unit; and predicting a fatigue crack initiation position and orientation based on the dimensionless damage index. According to the method, the fatigue crack initiation position and orientation of the engineering material can be quantitatively predicted, and the limitation that a cyclic cohesion model can only accurately predict the fatigue crack propagation stage is overcome.

The invention relates to an anti-cracking analysis method for a mass concrete structure, and belongs to the field of concrete construction. According to the technical scheme, the mass concrete structure crack resistance analysis method comprises the following steps that S1, a mass concrete structure simulation analysis model is established with a concrete formula, the size, the construction technology and the use environment as constraint conditions, and the mass concrete structure simulation analysis model comprises a bearing platform and a main beam; s2, constructing a bearing platform heat exchange model, and calculating a temperature field; s3, constructing a stress calculation model according to the bearing platform heat exchange model and the temperature field, and calculating a stress field; and S4, according to the stress field, analyzing the early cracking possibility and crack distribution of the mass concrete structure simulation analysis model through principal tensile stress discrimination and an extended finite element method. According to the scheme, the technical problem that multi-factor coupling is insufficient in a traditional simulation method is solved, the defect that crack distribution cannot be analyzed due to the fact that the prior art only depends on a single index is overcome, and a comprehensive basis is provided for formulating targeted anti-crack measures.

The invention discloses a second-order backward difference stable generalized finite element method for a parabolic interface problem, and relates to the technical field of engineering application of stable generalized finite element methods, a stable generalized finite element method (SGFEM) is used for discretizing space variables, a second-order backward difference formula (BDF) is used for time discretization, and a stable generalized finite element method is used for discretizing space variables. A numerical value test verifies that the algorithm has the optimal convergence rate under an infinite norm and an L2 norm, a numerical value result shows that the algorithm shows unconditional convergence under a large time step, and a new solving strategy is provided for the parabolic equation interface problem.

The invention belongs to the field of multi-physical field numerical calculation of power equipment, and discloses an electric field-fluid field coupling calculation method and device for oil-immersed power equipment, and the method comprises the steps: carrying out the unit subdivision of a geometric solution model, and reading the node information of a subdivision unit; obtaining the position of a gas-liquid interface in the subdivision unit at the current moment by utilizing a VOSET gas-liquid interface tracking method; based on the gas-liquid interface position in the subdivision unit at the current moment, determining the unit type of the subdivision unit at the current moment; in combination with an extended finite element method or a finite element method, the electric field force borne by the surface of the suspension bubble at the current moment is solved; the electric field force borne by the surface of the suspension bubble at the current moment is coupled into the fluid field control equation, a finite volume method is used for solving, and a fluid field index under the action of the electric field at the current moment is obtained; according to the method, numerical calculation is accurately and quickly performed on the coupled electric field-fluid field containing the dynamic characteristics of the suspended bubbles, and the calculation cost is effectively reduced.

The present application relates to a kind of fatigue crack propagation life extension finite element analysis method, comprising the following steps: establishing three-dimensional solid model, simplifying three-dimensional solid model, obtaining fatigue crack tip stress distribution, obtaining fatigue crack propagation life.The process of obtaining fatigue crack propagation life includes measuring the length of metal structure fatigue crack, calculating the critical equivalent strain energy release rate of metal structure fatigue crack tip, calculating fatigue crack propagation life.The method of the present application applies virtual crack closure technique to the extended finite element method, achieves the purpose of simulating crack propagation without pre-specifying crack propagation path, thereby generating fine mesh at crack tip, saving the time required for modeling, reducing workload, and improving the accuracy of crack propagation life calculation.

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 invention relates to the field of computational mechanics, finite element analysis post-processing and surface metrology, and particularly provides a crack surface grid data processing method and software for XFEM (Extended Finite Element Method) simulation output. The method combines grid topology connectivity analysis, a feature clustering algorithm, reference plane fitting and surface quality evaluation to realize automatic identification and visualization of the crack surface component. The method is suitable for post-processing and quality evaluation of complete crack surface data in the fields of aerospace structures (such as turbine blades), chip production (such as wafer breakage) and the like. A crack surface formed by an XFEM method is generated from the inside of a grid, but abaqus software only provides grid node coordinates near the crack surface and displays the crack surface, so that the specific morphology of the crack surface is difficult to accurately describe, and the surface index of the crack surface cannot be directly calculated. According to the method, visualization and morphology index calculation can be carried out on the crack surface based on the simulation result obj file, whether the simulation result is qualified or not is judged, and the limitation of software is supplemented.

A two-stage full life prediction method for titanium alloy fatigue crack based on finite element analysis, a damage mechanics model is established for the titanium alloy structure to be tested, and the fatigue crack initiation stage simulation is carried out, the fatigue crack initiation life and the initial crack position are obtained; the fatigue crack propagation rate model is established based on fracture mechanics, and the propagation stage simulation is carried out at the initial crack position through the extended finite element method, and the fatigue crack propagation life is obtained; the fatigue crack full life of the titanium alloy structure to be tested is obtained by fusing the simulation results of the two stages. The present application is based on damage mechanics and fracture mechanics, by considering the propagation characteristics of short fatigue cracks in the early failure stage, a bridge between the fatigue crack initiation finite element simulation and the macro crack propagation finite element simulation is built, the effective evaluation of the full life of the titanium alloy complex structure under complex load is realized, and the whole process of the fatigue crack from initiation to continuous expansion is intuitively shown.

The present invention provides a method for establishing an asphalt pavement life prediction model based on environment and load coupling analysis, comprising: using Abaqus software to establish a three-dimensional finite element model of the asphalt pavement, simulating the dynamic response of the pavement structure under the action of moving load and temperature, and obtaining the maximum tensile strain value at the bottom of each layer of the asphalt surface layer; combining the temperature correction coefficient, the humidity correction coefficient and the thickness correction coefficient to correct the model to improve the prediction accuracy; using the extended finite element method to simulate the expansion process of reflected cracks under the action of load, and calculating the composite stress intensity factor and its influence on crack expansion; referring to the Paris formula, introducing the equivalent crack damage rate, and constructing a life prediction model that considers the damage of crack expansion to the pavement structure; comprehensively considering the influence of temperature, humidity, load, the overall strain accumulation of the asphalt layer, the thickness of the pavement structure layer and reflective cracks, and establishing an asphalt pavement life prediction model based on finite elements for accurately predicting the service life of the asphalt pavement.

The invention provides a multi-scale extended finite element method calculation acceleration method based on a neural operator. The method comprises the steps that a complex structure is divided into a plurality of local substructures according to a division rule, and node coordinates and modulus distribution of the local substructures are extracted; inputting the local substructure into a trained neural operator model, and assembling a local stiffness matrix in the local substructure based on the neural operator model to obtain a substructure coacervation stiffness matrix; summarizing the cohesion stiffness matrixes of all the local substructures to form an overall stiffness matrix, and solving to obtain a coarse grid displacement solution of the complex structure; and mapping the displacement field of the complex structure from the coarse grid to the fine grid according to the coarse grid displacement solution and based on a neural operator model, and obtaining a global displacement solution of the complex structure. According to the method, fusion of the multi-scale extended finite element local structure is accelerated through neural operator calculation, efficient calculation is achieved while the physical mechanism of the complex structure is reserved, and rapid simulation and optimization of the designed complex structural part are facilitated.