446 results about "Finite element approach" patented technology

The invention relates to the technical field of collaborative optimization, in particular to a geometric parameter collaborative optimization method of a taper hole machining cutter, which comprises the following steps: by constructing a high-fidelity digital twin model, integrating multi-physics field coupling and machine tool dynamic characteristics based on a finite element method, generating a geometric parameter-performance data mapping set and training and calculating an agent model; outputting a Pareto solution set through multi-target global optimization; and constructing a constraint range based on the solution set, and calling a digital twin model to carry out local optimization to obtain an optimal geometric parameter combination. The method comprises a self-correction mechanism: correcting a material constitutive relation and a friction coefficient through experimental data; staged adaptive learning, NSGA-II and DBSCAN clustering are adopted, and the efficiency is optimized along with the method; and a Pareto stability index and transfer learning are introduced, so that the result robustness and the cross-task reusability are improved. According to the method, high-precision and high-efficiency geometric parameter collaborative optimization of the taper hole machining tool can be realized.

A solid structure deformation and damage analysis method based on a quasi-bond finite element method comprises: carrying out geometric modeling on a target structure body, and distribution and subdivision to generate a grid of a traditional finite element method; dividing the target structure body into a finite element region and a quasi-bond region, and calculating a finite element region system stiffness matrix and a quasi-bond region system stiffness matrix to obtain an overall stiffness matrix of the target structure body; setting a boundary condition for the target structure body, applying an external load, and calculating a system force matrix under current load and boundary state; and judging a quasi-bond breakage condition according to a node trial displacement, then calculating a node displacement of the structure body and an equivalent damage parameter at each node, and outputting cloud charts of a displacement field and an equivalent damage field.

The invention discloses a bronze ware ornamentation and pattern digital restoration method based on an image enhancement technology, and relates to the technical field of image restoration, and the method comprises the steps: building a space mapping matrix; extracting multi-modal data features by using the surface state of the topological insulator, and registering a joint data volume; forming a super-resolution image through super-resolution reconstruction; obtaining a material degradation coefficient by using a wavelet finite element method and a graph neural network; generating an adversarial network by utilizing physical constraints, and generating an embarrassment repairing result; a material sensing three-dimensional model is constructed by adopting a wavelet packet decomposition and neural radiation field fusion technology, texture mapping is dynamically adjusted based on a graphene Moire effect, and virtual-real fusion is performed through holographic waveguide AR; by combining advanced technologies such as a metamaterial lens, micro-distance laser scanning, a topological insulator film, a graphene heterojunction and a nerve radiation field, high-precision three-dimensional digital restoration and repair of bronze cultural relics are realized, and immersive augmented reality display experience is provided.

The invention discloses an energy storage battery thermal runaway damage diffusion early warning method based on a dynamic thermal model, and relates to the technical field of battery safety monitoring, and the early warning method comprises the specific steps: multi-source parameter collection: arranging a plurality of sensors to collect data, and preprocessing and storing the data; thermal stress modeling is conducted, units are divided through a finite element method to calculate thermal stress, and structural damage is judged in combination with a damage threshold value; multi-physics field cooperative calibration is carried out, and characteristic quantity is acquired and substituted into a formula to correct thermal stress; dynamic thermal model construction: introducing thermal stress influence to construct a model containing a damage diffusion term; thermal runaway early warning judgment is carried out, a multi-dimensional index system is constructed, a risk value is calculated, and early warning is triggered; through a multi-source parameter acquisition technology, in combination with temperature, current, voltage, ultrasonic wave and broadband impedance multi-dimensional sensor data, and assisted by external condition monitoring of environment temperature and humidity, heat dissipation system flow and rotation speed, comprehensive perception of the working state of the battery is realized, and richness and accuracy of data acquisition are improved.

The invention discloses a ship shafting reliability evaluation method and system based on multiple working conditions, and the method comprises the steps: collecting multi-source data of a ship propulsion system through integrating multiple sensors; constructing a dynamic load spectrum based on a time-varying Copula function in combination with parameters such as a stress distribution function and a degradation amount distribution function; a reduced basis finite element method is adopted, experimental strain data are collected, and a reduced-order basis matrix is constructed; based on a three-stage Wiener degradation model, in combination with parameters such as a material degradation rate, activation energy and a temperature average value, the residual life of the ship propulsion system is predicted, and model parameters are adjusted in real time through a Bayesian dynamic updating mechanism; building Hamiltonian through physical constraint reinforcement learning, and optimizing operation parameters of the ship propulsion system in combination with a fault probability threshold value and an energy change rate threshold value; a digital twin engine is utilized to provide real-time visual output. According to the invention, the service life is prolonged to the greatest extent while the system meets the performance requirements; and monitoring and decision making by operators are facilitated.

The invention discloses a new energy automobile speed reducer efficiency optimization system based on multi-physics field coupling, and belongs to the technical field of new energy automobiles. The system constructs a structure-heat-fluid multi-physics field intensity coupling simulation model: firstly, the structure-heat model calculates friction heat generated by gear engagement based on a finite element method; then, the heat source is input into a heat-fluid sub-model to calculate a whole machine temperature field and oil stirring loss; the key point is that the temperature field can perform bidirectional feedback to update material attributes, lubricating oil viscosity and thermal deformation in real time, and a high-fidelity coupling solution is obtained through iterative solution. Based on the precise model, the system adopts intelligent optimization methods such as a genetic algorithm to carry out iterative optimization on variables such as gear parameters or lubricating oil viscosity, and outputs a design combination enabling the comprehensive efficiency to be optimal. According to the invention, the strong coupling effect among force-heat-fluid is accurately simulated, the deviation of traditional decoupling analysis is overcome, and the efficiency of the speed reducer and the energy efficiency of the whole vehicle can be systematically improved.

The invention belongs to the field of winding temperature control, and relates to a PCA-FCNN-based converter transformer valve side winding oil flow temperature rise calculation method, which analyzes a thermodynamic conduction process in a valve side winding, determines a characteristic variable having the highest correlation with a temperature field, performs high-correlation characteristic variable parameterization setting by using Latin hypercube sampling, and calculates the oil flow temperature rise of the valve side winding. A valve side winding flow-heat coupling calculation model is established, and finite element calculation software is used for flow-heat coupling calculation; constructing a data set of a calculation model by taking the parameterized characteristic variable as an input characteristic quantity and taking the valve side winding oil flow temperature rise calculated by a finite element as an output characteristic quantity, dividing the data set into a training set and a test set, and generating a valve side winding oil flow temperature rise rapid calculation model with relatively high precision by setting model training parameters; a validation set other than the model data set is set to validate the accuracy of the computational model. According to the method, the required calculation time is shortened by about 300 times compared with the calculation time of a finite element method, and the calculation speed of the oil flow temperature rise of the valve side winding is increased.

The invention discloses a cross-scale multi-physics-field coupling aero-engine warming-up process analysis method. The method comprises the steps that firstly, an engine air system one-dimensional network model, a fuel and lubricating oil system one-dimensional network model, a wheel disc and cartridge receiver two-dimensional axial symmetry model, a blade parameterization model and a main runner quasi-one-dimensional model are established; then calculating an air system boundary and a fuel and lubricating oil system boundary by using a main runner cavity method, then calculating the fuel and lubricating oil system boundary and the air system boundary by using a one-dimensional transient fluid network method to obtain a heat exchange boundary of a wheel disc and a cartridge receiver, and considering a thermal load and a centrifugal load in an unsteady state heat conduction process; calculating the radial displacement of the wheel disc and the casing by using a two-dimensional axisymmetric finite element method, and calculating the temperature and the radial displacement of the blades by using an engineering algorithm; and finally, integrating the radial displacement of the wheel disc, the blades and the casing and the initial blade tip clearance value to obtain the blade tip clearance value of each stage in the transient process, and feeding back the blade tip clearance value to the mainstream model again to realize iterative calculation. The analysis precision of each physical field is improved, and the calculation time consumption is reduced.

The invention provides a DCIM-based method for rapidly calculating a green function of a uniaxial anisotropic layered medium and an electromagnetic simulation system. The method comprises the following steps: modeling a uniaxial anisotropic layered medium to be simulated; determining a uniaxial anisotropic dielectric material of each layer, and assigning transverse parameters and longitudinal parameters; determining longitudinal coordinates of field point and source point distribution required to be solved, fitting a uniaxial anisotropic medium Green function spectral domain expression under the field source distribution by using a DCIM method, and solving an analytical expression in a spatial domain by using Somerfeld identical equation properties; solving the size of the electromagnetic field on the plane according to the fitted analytical expression; compared with a direct numerical integration method or a finite element method numerical solution using the Green function, the method has the advantages that the airspace analytical expression corresponding to the field source distributed on the plane is directly fitted, so that the solution of the airspace Green function is greatly accelerated, and the calculation efficiency and the calculation precision are both good in an actual example.

The present application relates to the field of additive manufacturing, and discloses a simulation method for determining a laser powder bed fusion printing process for single-crystal austenitic stainless steel. The simulation method comprises the following steps: S1, establishing a three-dimensional polycrystalline powder bed microstructure model; S2, establishing a three-dimensional temperature field prediction model on the basis of a finite element method; S3, establishing a three-dimensional polycrystalline microstructure evolution model by using a phase-field method; and, S4, coupling the models from steps S1, S2 and S3, and simulating a multi-layer, multi-pass laser powder bed fusion process by using different process parameters, so as to determine appropriate single-crystal process parameters. The present invention replaces conventional trial-and-error experimental methods with numerical simulation methods to determine single-crystal process parameters, thereby greatly reducing the time and economic costs of process exploration, and assisting experiments in revealing the microstructure evolution mechanism of single crystal preparation via laser powder bed fusion additive manufacturing.

The invention discloses a biconical antenna balun equivalent circuit modeling optimization method based on a multi-conductor transmission line, and belongs to the technical field of electromagnetic simulation. The method comprises the following steps: firstly, establishing a three-dimensional electromagnetic model of a biconical antenna balun based on a finite element method, and setting ports and defining boundary conditions in combination with an actual current transmission path; then, distribution parameters among conductors are extracted through a multi-conductor transmission line theory, and a Balun circuit topological structure is constructed; and finally, taking the antenna coefficient as an optimization target, carrying out iterative optimization on equivalent circuit element parameters by adopting a multi-target genetic algorithm, considering a plurality of optimization targets in a broadband range, and finally obtaining a high-precision equivalent circuit model. Through combination of electromagnetic simulation and an intelligent optimization algorithm, high-efficiency extraction of complex Balun structure distribution parameters and adaptive optimization of circuit parameters are realized, and the simulation precision of the biconical antenna is remarkably improved.

The invention belongs to the technical field of nuclear reactor physical numerical calculation, and particularly relates to a method for improving precision and convergence of solving a diffusion equation based on a PINN, and the method comprises the following steps: S1, building a neural network algorithm model combining a physical information neural network PINN and source iteration; s2, aiming at a multi-region smooth transition neutron diffusion problem with small cross section difference between materials, optimizing the neural network algorithm model by adopting an optimization strategy of a training level; and S3, aiming at the multi-region neutron diffusion problem of large neutron flux gradient at the boundary due to large cross section difference between materials, improving the neural network algorithm model by adopting a domain-divided neural network architecture. According to the method, the problem that the calculation cost is exponentially increased in a high-dimensional or complex geometric scene due to the fact that a traditional finite difference method and a finite element method depend on grid division is avoided.

The invention discloses a method for inhibiting temperature fluctuation of an oriented silicon steel BAF furnace, which comprises the following steps: adding 0.005-0.01 wt% of Nb, and forming a nanoscale Nb (C, N) precipitate; a three-dimensional heat conduction model is established in a mode of linkage of infrared thermal imaging and electromagnetic induction heating in combination with a finite element method, and real-time monitoring and accurate control of a temperature field in the furnace are achieved. On the basis of a fuzzy PID hybrid control strategy, the optimal heating power and scanning path are predicted in combination with a convolutional neural network, and closed-loop control of local temperature compensation is achieved; a random forest model with the temperature gradient delta T, the Als content and the Nb precipitated phase density as input parameters is constructed, technological parameters are iteratively optimized in combination with a genetic algorithm, and dynamic self-adaptive adjustment of an annealing temperature curve is achieved. According to the method, uniform growth of Gaussian grains in the secondary recrystallization process is achieved, and the effects of reducing annealing temperature fluctuation, improving secondary recrystallization uniformity and optimizing grain orientation distribution are achieved.

The invention discloses a carbon dioxide geological sequestration quantity prediction method, system and device and a storage medium, and the method comprises the steps: obtaining a mathematical expression of carbon dioxide sequestration capacity through combining a coupling model of a flow field, a mechanical field and a thermal field with random parameters, and introducing a leakage risk coefficient; taking the weighted sum of the expected value of the storage capacity and the variance as an optimization objective function, and according to the mathematical expression of the carbon dioxide storage capacity, carrying out optimal solution solving on the carbon dioxide storage capacity to obtain an optimal storage strategy; performing spatial discretization on the control equation by adopting a finite element method, discretizing time by adopting a semi-implicit difference method, discretizing random variables by combining a random Galkin method, and solving a coupling model of a flow field, a mechanical field and a thermal field to obtain a prediction result of the carbon dioxide sequestration amount; and according to a prediction result of the carbon dioxide sequestration amount, outputting an expected value and a variance of the sequestration capacity, and generating a sequestration amount distribution diagram, a risk assessment diagram and a sensitivity analysis diagram.

The invention relates to the technical field of water conservancy projects, in particular to an anti-seepage control system for an earth rock cofferdam. The method comprises the following steps: periodically acquiring external hydro meteorological data and internal structure response data of a cofferdam through a sensor group based on a monitoring unit; establishing a multi-field coupling model based on a finite element method through a model building unit, and dynamically coupling a wave load, a tidal water level and an osmotic pressure field; the minimum cofferdam crest elevation is determined by comparing the difference between the minimum safety coefficient and a preset safety coefficient on the basis of a decision-making unit; and based on the analysis unit, inputting the minimum cofferdam crest elevation into the multi-field coupling model to obtain the maximum value of the hydraulic gradient of the escape point of the downstream slope within a third preset time period, determining an anti-seepage state based on the maximum value, and adjusting related parameters based on the anti-seepage state. The seepage risk of the cofferdam is monitored, predicted and actively controlled in real time, so that the seepage rate of the earth rock cofferdam is reduced.

The invention provides a gallium nitride radio frequency device multi-physics field coupling modeling and verification method and system, and relates to the technical field of modeling, and the method comprises the steps: carrying out the dynamic coupling calculation of physical parameters of a device through a temperature variation iterative algorithm, and building an electrothermal coupling field distribution function; constructing a self-adaptive iterative calculation equation to calculate high-frequency working state physical characteristic parameters; performing discretization processing by adopting a finite element method to obtain field distribution parameters; and correcting the coupling prediction equation based on the measured parameters of the low-frequency working state. According to the method, the model precision can be improved, and the calculation complexity of the gallium nitride radio frequency device model is reduced.

The invention discloses a concrete panel tensile crack damage calculation method and a concrete panel tensile crack damage calculation system, which combine extended finite element calculation with a concrete tensile crack damage calculation model, accurately simulate crack behaviors in concrete, and are particularly suitable for numerical simulation requirements under the conditions of complex crack networks and large-scale damage. According to the method, the expansion finite element method is introduced, subtle changes of crack starting, expansion paths and final forms are captured on the premise that the calculation cost is not increased, the common problem of grid dependence in a traditional finite element method is avoided, fine division or frequent updating of grids is not needed, and the calculation efficiency is improved. The method reduces the preprocessing time and iteration times, reduces the consumption of overall computing resources, can accurately describe the expansion path of the crack and the nonlinear mechanical behavior of the concrete, and is suitable for the simulation of a complex crack network.

The invention discloses a low-frequency sound propagation loss forecasting method suitable for a polar region sea area, and the method comprises the steps: building a two-dimensional ice layer model of a forecast sea area according to remote sensing data based on the setting that sea ice of the polar region sea area is a uniform elastic medium; calculating hydrological conditions of the ocean sound channel of the polar sea area; establishing a forecast sea area two-dimensional seabed model according to the seabed topography sediment database; an under-ice sound field model is constructed based on a three-dimensional cylindrical coordinate system, sound pressure from unit intensity sound sources with different sizes and depths to a receiving point in a forecast sea area is calculated through a frequency domain finite element method in combination with a PML technology, and sound propagation loss of a needed position is obtained through calculation. According to the method, the application limitation of traditional ray and normal wave theories under complex boundary conditions is broken through through a finite element method, a synergistic effect mechanism of actual ice layer parameter space change, submarine topography fluctuation and sound velocity profile gradient characteristics is systematically analyzed, and sound field modeling is more accurately carried out on different ice layers and submarine topographies in the Chukong sea region all year round; the influence of sound wave propagation is simulated.

The invention relates to the technical field of vibration active control and artificial intelligence, and discloses an aero-engine fan rotor keyless phase virtual dynamic balance method and system based on a finite element method, and the system comprises a modeling and simulation module which is configured to obtain the first-order critical speed and vibration mode of an initial rotor dynamics simulation model; the model calibration module is configured to calibrate the initial rotor dynamics simulation model according to the first actual amplitude to obtain a calibrated rotor dynamics simulation model; the model updating module is configured to update the calibration rotor dynamics simulation model to obtain an updated rotor dynamics simulation model; and the trial weight and counterweight module is configured to substitute the second actual amplitude into particle swarm optimization, calculate the actual total unbalance amount of the rotor system and the trial weight angle difference, and finally add a counterweight and select a direction until the vibration is reduced to realize dynamic balance. According to the invention, the position of the unbalance can be accurately determined only through amplitude analysis.

The invention provides a glue joint insulation joint fatigue damage evaluation method and system considering random parameters, and relates to the technical field of rail vehicle wheel-rail contact analysis, and the method comprises the steps: obtaining first information; establishing a dynamic contact model of the wheel and the cementing insulation joint according to the first information, and performing simulation to obtain a dynamic response parameter in the contact process of the wheel and the track; performing fatigue damage analysis according to the dynamic response parameters to obtain fatigue damage parameters; performing fatigue life prediction according to the fatigue damage parameter to obtain a fatigue life prediction result; performing sensitivity analysis according to the fatigue life prediction result to obtain a sensitivity analysis result; and calculating the failure probability of the glue joint insulation joint according to the sensitivity analysis result, and evaluating the reliability of the glue joint insulation joint. According to the method, the dynamic contact model of the wheel and the cementing insulation joint is established by using the finite element method and simulation is carried out, so that high-precision wheel-rail contact dynamic response parameters are directly obtained.

The invention discloses a foundation pit seepage-deformation space-time coupling early warning method and system based on a large geological model, and belongs to the technical field of geotechnical engineering intelligent monitoring, and the method comprises the steps: processing a regional geological survey report through the large geological model based on a Transform architecture, and generating a high-precision three-dimensional stratum parameter field; further, an improved particle finite element method is adopted to carry out dynamic coupling solution of a seepage field and a stress field, a displacement rate vector is obtained, a hybrid network space-time prediction model fused with LSTM-Transform is constructed, a composite early warning index is calculated in combination with the real-time displacement rate vector, and through multi-source data fusion and space-time coupling analysis, an early warning result is obtained. Accurate evaluation and advanced early warning of the seepage stability and the deformation state of the deep foundation pit project are achieved, the accuracy and reliability of early warning signals are remarkably improved, and the method is suitable for foundation pit safety control under complex geological conditions.

A method for simulating cross-seasonal heat storage of a buried pipe well group in a geothermal reservoir is characterized in that hot water and cold water are respectively injected in different seasons by arranging different injection ports in a countercurrent cross injection mode, so that a relatively balanced temperature distribution pattern of a'hot area 'and a'cold area' is formed in a stratum, and the volume structure of a buried pipe is simplified into a line unit model; discretizing the pipeline area by adopting a finite element method; on the basis, initial temperature field distribution of soil and initial parameters of fluid in a buried pipeline unit are set, a proper numerical solution method is selected to solve the pipeline unit model, and the stability of the calculation process and the accuracy of the result are ensured through real-time monitoring; in order to further analyze the influence of underground water seepage on the system performance, an underground water seepage module is introduced, and the difference between summer refrigeration and winter heat supply effects under the seepage condition or not is compared and researched; the invention further comprises a system, equipment and a storage medium for implementing the method.

The invention discloses a deep sea ultra-shallow gas layer drilling shaft multiphase flow obstacle risk prediction method, and relates to the technical field of petroleum and natural gas engineering, and the method comprises the following steps: building a shaft-sedimentary layer heat-force-solid-chemical multi-physics field coupling model and a 3D model, setting initial boundary conditions, and dividing grids; model parameters are input, a finite element method is used for solving a multi-physics field coupling numerical value, and the gas invasion amount and the hydrate blocking rate are calculated; analyzing a gas invasion-migration-pressure evolution mode; researching the secondary generation and deposition characteristics of the hydrate; establishing a risk assessment system based on the parameters to divide risk levels; a historical data verification model is selected, and when the deviation rate exceeds 15%, parameters are optimized and solution is carried out again. According to the method, the defects of traditional single-field analysis are overcome, the multi-phase flow obstacle risk prediction accuracy is improved, intervention guidance is provided, model verification guarantees stability, safe and efficient mining of the deep sea ultra-shallow gas layer is assisted, and related development technology progress is promoted.

The invention discloses a soil-pile foundation collaborative response seismic liquefaction discrimination device and method based on seismic oscillation time-frequency characteristics, and the method comprises the steps: building a multi-field coupling evolution model comprising a soil body domain, a fluid domain and a structural body, constructing a variable-scale grid architecture through a finite element method, balancing the high sensitivity and calculating the load, and carrying out the calculation of the load. Meanwhile, the fluid domain is directly coupled with the soil body unit through the shared node, and the Poisson's ratio is dynamically calibrated according to the void ratio. The multi-field coupling modeling mode can accurately simulate a soil-water-structure collaborative response mechanism, the problem of time-frequency characteristic mismatch caused by a scale effect in the prior art is avoided, and the strength degradation law and the aging characteristic of the in-situ soil body are accurately reflected. Compared with a traditional physical model which cannot reproduce nonlinear dynamic response under complex geological conditions, the method has the advantages that accurate description of high void ratio and low permeability of the soft sand is realized through numerical modeling, and the reliability of seismic liquefaction judgment results is further improved.

The invention relates to the technical field of acoustic functional devices, and discloses an acoustic black hole lens based on a three-dimensional radial gradient refractive index phonon crystal structure and a design method, a three-dimensional radial gradient refractive index distribution function n (r) with a center convergence characteristic is constructed, and incident sound waves are continuously guided and efficiently focused to the center of the lens in the propagation process; combining the feasibility constraint of an additive manufacturing process, designing a few-negative micro-lattice structure unit for realizing the gradient refractive index distribution, and determining key geometric parameters of the few-negative micro-lattice structure unit; according to the refractive index distribution function n (r), radially arranging the micro-lattice units in a three-dimensional space, and constructing an initial lens model; the sound field distribution, focusing performance and energy convergence efficiency of the model are verified and iteratively optimized in a mode of combining analytical modeling and finite element method simulation, and a three-dimensional radial gradient refractive index photonic crystal acoustic black hole lens design model with wide-angle incidence compatibility and broadband response capability is obtained.

The present invention relates to the technical field of the intersection of computational mechanics and deep learning, and specifically to a deep learning method that combines a physical information neural network with a finite element method; specifically, partial differential equations are embedded into a neural network, comprising the following steps: S1, meshing the solution domain, and calculating the stiffness matrix and the node load array; S2, collecting observation data and boundary conditions; S3, using the energy represented by the stiffness matrix and the fitting error of the observation data as a loss function to train the neural network; S4, executing an optimization algorithm to optimize the neural network; S5, and repeating the training and optimization steps until convergence; the deep finite element method proposed in the present invention combines a physical information neural network with a finite element method, and exhibits significant advantages and beneficial effects in terms of the fusion of physical knowledge and observation data, modeling process and loss function design, model training stability and simplicity, computational efficiency and accuracy, pre- and post-processing technology and transfer learning capability, and applicability.

The invention relates to a flexible direct-current power transmission system stress analysis method based on multi-physics field coupling, and the method comprises the following steps: constructing a three-dimensional model of equipment based on the equipment operation data of a flexible direct-current power transmission system; coupling the three-dimensional model of the equipment with an electric field, a temperature field and a mechanical field to obtain a multi-physical field coupling model of the equipment; performing simulation based on the multi-physics field coupling model of the equipment, and solving the multi-physics field coupling model of the equipment through a finite element method in the simulation process to obtain a stress analysis result of the equipment; according to the method, the interaction of various physical factors in the flexible direct current system can be comprehensively captured, the problem of insufficient precision caused by the fact that only steady state or single field influence is analyzed in a traditional method is solved, and the authenticity and accuracy of stress prediction are remarkably improved.

The invention provides a robot full-flexible rigid-flexible coupling parametric modeling method and system, and belongs to the technical field of robot modeling. According to the method, firstly, based on MDH flexible expansion parameters, a floating coordinate method, a finite element method and a Rayleigh beam model are combined, and a full-flexible kinematics model containing flexible deformation of a base, joints and connecting rods is established; secondly, the speed and acceleration of key nodes of the model and any point of the flexible connecting rod are calculated in a recursive mode; constructing a local kinetic equation of each concentrated mass component and each distributed mass component based on a virtual power principle, and converting the local kinetic equations into a generalized coordinate space through a generalized Jacobian matrix; and finally, assembling to form a unified robot rigid-flexible coupling kinetic equation. According to the method, high efficiency and automation of the modeling process are realized, the accuracy of the model for describing the dynamic characteristics of the robot is improved, and an accurate basic model is provided for high-precision dynamic analysis and control of the robot.

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 provides a near-wellbore hydraulic fracture deformation and expansion heat-fluid-solid coupling simulation method and system, and the method comprises the steps: generalizing a reservoir rock mass into a matrix and a fracture, building a heat-fluid-solid coupling mathematical model, and describing the mechanical processes of fluid flow, heat conduction and convection, rock mass deformation and fracture expansion; a three-dimensional displacement discontinuous method DDM and a virtual stress method FSM are adopted to calculate the induced stress of the fracture and the induced stress of the shaft respectively, and fluid flow, temperature change, matrix deformation and mass heat exchange of a matrix and the fracture are calculated through a finite volume method and a finite element method; on the basis of linear elastic fracture mechanics, the crack propagation direction and speed are calculated in combination with the maximum circumferential stress criterion and the Paris scale law; and a dynamic grid fracture front edge tracking technology is adopted to update the fracture form, a three-dimensional non-planar fracture expansion model is formed, and near-wellbore hydraulic fracture full-process simulation is realized.