22 results about "Tetrahedral meshes" patented technology

This invention belongs to the field of numerical electromagnetic field solution, specifically a mesh adaptive method based on reconstructive posterior error estimation. The invention first performs finite element modeling of the target microwave component, introducing boundary conditions and excitations to establish a corresponding electromagnetic simulation model. Then, a tetrahedral mesh is used to divide the solution domain, and finite element electromagnetic simulation analysis is performed on the model to calculate the electric field at the centroid of the four faces of the tetrahedral mesh. The least squares principle is then used to refit the electric field on the tetrahedral mesh to reconstruct a first-order linear fitting expression. Next, the reconstructed solution at the nodes is calculated using the reconstructed fitting expression, and posterior error estimation is performed based on the electric field at the nodes. Finally, the mesh is refined according to the error on the tetrahedral mesh, and finite element electromagnetic simulation analysis is performed again until the finite element solution meets the accuracy requirements. This invention has the advantages of simple engineering implementation, low computational cost, and high universality.

This invention discloses a method for generating tetrahedral meshes of defective electromagnetic geometric models based on a background tree. The method includes: discretizing the input electromagnetic geometric model into an initial triangular mesh based on geometric parameters; using this as boundary constraints, constructing an initial tetrahedral mesh covering the computational domain using a fault-tolerant generation method; organizing the sub-meshes generated from each independent entity of the model into a background tree; using this background tree and a counting mechanism to determine the geometric indices of each connected region of the initial mesh; for cases where the indices are not unique, assigning indices based on material priority and updating the boundary surfaces; finally, refining the mesh according to wavelength and port to obtain an initial mesh without geometric errors. This invention can effectively handle significant geometric defects and stably generate high-quality, non-degenerate tetrahedral meshes.

The present application belongs to the technical field of electromagnetic simulation, and specifically provides a residual error estimation non-conformal adaptive encryption volume integral equation electromagnetic simulation method to complete high-precision and high-efficiency electromagnetic simulation of complex multi-scale non-uniform targets. The present application proposes a grid error estimator for volume integral equations, performs error analysis on each tetrahedral grid to obtain error distribution of the grid; then sets an error percentage threshold, selects the grid with the largest error according to the error percentage threshold to mark, and performs non-conformal bisection encryption on the marked grid, thereby completing non-conformal adaptive encryption based on grid error. On the premise of increasing a small amount of calculation unknowns, the grid quality is greatly improved, and the calculation precision and calculation efficiency of electromagnetic simulation are improved. In summary, the present application proposes a residual error estimation non-conformal adaptive encryption volume integral equation electromagnetic simulation method, which is especially suitable for electromagnetic characteristic calculation of complex multi-scale non-uniform targets.

This invention relates to a time-domain electromagnetic simulation method based on Tree-Cotree decomposition and a hybrid DG-FE / SE domain decomposition. The method includes: dividing the computational domain into a tetrahedral finite element subdomain and a hexahedral spectral element subdomain according to geometric dimensions and electromagnetic properties; constructing a minimum spanning tree and cotree based on mesh edges to apply Gaussian divergence constraints; discretizing both the finite element and spectral element regions using scalar and vector basis functions to obtain Galerkin weak solutions; uniformly processing the interface between the finite element and spectral element subdomains using a topology identification-polygon decomposition-Gaussian integration method, and combining this with upwind flux to achieve continuous field transfer; assembling the spatial discretization matrix of the Galerkin weak solutions, and completing time propagation using an explicit fourth-order Runge-Kutta scheme. Compared with existing technologies, this invention systematically eliminates the low-frequency collapse problem, ensures the non-singularity of the system matrix, and guarantees solution accuracy and efficiency.

The application belongs to the technical field of three-dimensional electromagnetic radiation numerical solution, and relates to an electromagnetic radiation simulation analysis method based on local grid self-adaptive division. Firstly, the application carries out finite element modeling on a target antenna, introduces PML boundary and wave port excitation to establish a corresponding finite element calculation domain model, and adopts tetrahedral grid division to classify the calculation domain model; then finite element electromagnetic radiation simulation analysis is carried out to obtain finite element solution, and error estimation and encryption strategy are used to give the encryption size of the grid nodes in the non-PML region; finally, the grid is encrypted, finite element electromagnetic radiation simulation analysis is carried out again, and the process is repeated until the overall solution error is less than the set error limit, the final calculation grid is obtained, and finite element electromagnetic radiation simulation analysis is carried out. The application only encrypts the tetrahedral grid in the non-PML calculation domain, ensures the original characteristics of the tetrahedral grid in the PML calculation domain, and realizes the rapid simulation design of the antenna radiation characteristics while ensuring the calculation accuracy.

This invention provides a method and system for optimizing the performance of engine stealth coating components in service, belonging to the field of high-temperature engine technology. The method includes: acquiring measured data from the service environment to construct a coating substrate model and a thermo-mechanical coupling and radiation force control model; generating a non-uniform heat flux load distribution based on the coating substrate model, and combining this with the control model to obtain the high-temperature surface temperature gradient trend to obtain the stealth coating stress distribution; dividing the coating substrate model into a dense interface region and a defect edge region based on this distribution; obtaining a coating substrate mesh model based on a hexahedral mesh of the dense interface region and a tetrahedral mesh of the defect edge region; obtaining predicted stress distribution data based on this mesh model to obtain the interface delamination crack initiation path; and predicting the stealth coating life degradation trend based on this crack initiation path to optimize the performance of the target engine stealth coating components in service. This invention can improve the reliability of performance optimization for engine stealth coating components in service.

The present application relates to the technical field of atmospheric data, and specifically provides a fast interpolation method for scattered data of parameter solution of embedded atmospheric data system. The method first selects a pressure hole layout through computational fluid dynamics simulation, and constructs a parameter solution coefficient related to a Mach number, an attack angle and a sideslip angle, to form three-dimensional scattered data. Further, the scattered data points are subjected to Delaunay triangulation to generate tetrahedral grids that are not connected to each other. In order to accelerate the query, an anisotropic space hash grid is created, and each grid is associated with tetrahedrons in its coverage range. During the solution, the solution coefficient calculated according to the measured pressure value is used to locate the hash grid, irrelevant tetrahedrons are excluded through axial bounding box preliminary screening, and finally the remaining tetrahedrons are traversed and the specific tetrahedron where the measured point is located is accurately positioned through the calculation of the barycentric coordinates. Finally, the atmospheric parameters of the vertices of the tetrahedron and the barycentric coordinates are used for interpolation to obtain the Mach number, the attack angle and the sideslip angle.

The application relates to the technical field of atmospheric data and belongs to the technical field, and provides an embedded atmospheric data system parameter solving method based on triangulation. The method comprises the following steps: performing aerodynamic simulation on an airplane in a full envelope range, and selecting a suitable surface pressure hole layout; constructing a parameter solving coefficient sum for the pressure hole layout; constructing a numerical table of the parameter solving coefficient sum under a series of Mach numbers, attack angles and sideslip angles, forming three-dimensional data with the sum as a coordinate axis; performing spatial division on scattered data points (x, y, z) through a Delaunay triangulation method, forming a tetrahedral mesh in a three-dimensional space; positioning the position of (x, y, z) obtained by the pressure hole measurement value through a DT.pointLocation method in Matlab, determining the tetrahedral mesh where the (x, y, z) is located; and solving corresponding atmospheric data parameters through interpolation. The algorithm performance is reliable, and atmospheric parameters can be accurately solved according to the pressure measurement value of the embedded pressure sensor.

The application discloses a kind of whole hollow composite multi-point low-speed impact damage behavior prediction methods, belong to the field of impact simulation analysis of composite material structure.The method of the present application comprises: according to CT scanning, the establishment whole hollow composite cell model, based on cell model establishes panel micro model and divides tetrahedron grid, gives material attribute, to meet displacement continuity and stress continuity, obtains panel mechanical parameter, based on the obtained panel mechanical parameter establishes macroscopic micro-coupling finite element model, to model is applied first and second low-speed impact load and carries out finite element calculation, obtains damage behavior.The present application can accurately predict the damage behavior of whole hollow composite under multiple low-speed impact load, and can provide theoretical basis for composite structure design and engineering application.

The application provides a method and device for image labeling, electronic equipment and storage medium, the method comprising: surrounding a deformable object in a non-deformed state and a motion capture tracking device to obtain an initial surround shot image; reconstructing the image to obtain an initial tetrahedral mesh and a first three-dimensional coordinate of a spherical marker point in a reconstructed coordinate system; transforming the initial tetrahedral mesh to a motion capture system coordinate system according to the first three-dimensional coordinate and a second three-dimensional coordinate in the motion capture system coordinate system to obtain a calibrated tetrahedral mesh; and based on the calibrated tetrahedral mesh and a motion trajectory of a preset marker point on the deformable object during a deformation process, generating 4D labeling data by physically optimizing the deformation process when a quasi-static equilibrium condition is met. The application realizes high-precision automatic labeling of soft motion in a real scene, ensures the physical consistency of the labeling data, and provides high-quality data support for embodied intelligent algorithms.

The application discloses a lung tissue deformation simulation method and system based on genetic algorithm optimization flexibility, and the method comprises the steps of: constructing a lung tetrahedral mesh model, adding volume constraints and shear constraints to the lung tetrahedral mesh model; applying a test force simulating the pushing and pulling of a surgical instrument to the lung tetrahedral mesh model; predicting the position of each node in the lung tetrahedral mesh model at the next moment; solving the volume constraints and shear constraints to obtain the volume position deviation and the shear position deviation, correcting the node position at the next moment according to the volume position deviation and the shear position deviation, repeating the correction process of the node position until a set iteration threshold is reached, and then outputting the final lung tetrahedral mesh model at the next moment; and performing graphic rendering and display on the final lung tetrahedral mesh model at the next moment; the application introduces a constraint model more in line with continuum mechanics, so that dynamic simulation with physical realism and real-time performance is realized on a high-resolution lung model.

The application discloses a kind of rock mass seepage mass transfer simulation advantage path identification and extraction method of fusion fissure-matrix influence.First, the three-dimensional geometric characteristic parameters of fissure network are obtained, a random three-dimensional discrete fissure network model, i.e.the original model Full-DFN of fissure rock mass is generated.Second, the fissure network is structured modeling, the intersection of fissure surface and fissure is respectively abstracted as the two vertex sets of two-part graph, the mapping relationship between "fissure surface-line" is established;Further, the weighted calculation of fissure length, opening, permeability multi-parameter constraint, the advantage path in the process of seepage mass transfer is identified and extracted;Then, the simplified fissure rock mass submodel Sub-DFN is constructed.Finally, the fissure surface of Sub-DFN and Full-DFN is triangulated, the rock matrix is tetrahedral meshing, and the grid element is data conversion, the fissure-matrix rock mass submodel Sub-DFM and the fissure-matrix rock mass full model Full-DFM are obtained, and then seepage and mass transfer simulation analysis is carried out.

This invention provides a well-to-surface frequency domain electromagnetic detection method, device, and electronic equipment. It includes constructing a holistic computational domain based on a three-dimensional geological model, setting a perfectly matched layer based on stretched coordinate transformation outside the model, and performing adaptive mesh generation based on posterior error estimation within this domain. This generates a locally refined unstructured tetrahedral mesh in the target area. On this tetrahedral mesh, first- or second-order vector finite element methods are used in H (curl) space to spatially discretize and solve Maxwell's equations in the frequency domain, achieving well-to-surface frequency domain electromagnetic forward modeling. This invention, through the synergy of adaptive meshing and vector finite element methods within a differentiable framework, balances accuracy and efficiency, improves forward modeling stability and imaging resolution, and provides a scientific basis for improving efficiency and saving costs in mineral resource exploration and development.

Disclosed herein are methods for graphing convolutional neural networks in tetrahedral meshes. In some embodiments, the methods include computing a volumetric Laplace Beltrami Operator. In some embodiments, the methods include feeding the LBO into a neural network. In some embodiments, the methods include down-sampling a tetrahedral mesh.

The application relates to a stable node integral calculation method for explicitly analyzing metal volume forming, which comprises the following steps: dividing a problem domain into a triangular or tetrahedral grid, and dividing a grid integral domain into a plurality of non-overlapping node integral domains based on nodes in the triangular or tetrahedral grid; performing node domain smoothing on the node integral domain based on triangular / tetrahedral strain components of the nodes, to obtain a smoothed domain; constructing an hourglass control between the nodes and adjacent nodes in the smoothed domain, and calculating hourglass forces between the nodes and the adjacent nodes; performing node integration on the nodes based on stress and deformation gradients of the nodes calculated by attributes of the nodes, to obtain original internal forces of the nodes; superimposing the hourglass forces borne by the nodes and the original internal forces of the nodes, to obtain internal forces of the stable node integral method; and solving discrete motion equations in explicit dynamics based on the internal forces of the stable node integral method, to obtain a dynamic response.

The embodiment of the application belongs to the technical field of flexible body mechanics analysis, and relates to a method, device and equipment for solving surface force based on a flexible body. The method for solving surface force based on the flexible body comprises the following steps: obtaining a stiffness matrix corresponding to the flexible body; the stiffness matrix is constructed based on an extended spring-mass model and a tetrahedral mesh corresponding to the flexible body; the extended spring-mass model is a spring-mass model for describing the relationship between force and displacement by using the partial derivative of the element strain energy density; obtaining current displacement information of a measurement node in the tetrahedral mesh corresponding to the flexible body; and solving the surface force of the flexible body based on the stiffness matrix and the displacement information of the measurement node, and combining a static force balance discrete iterative equation of the flexible body. The technical scheme adopted by the application can improve the efficiency of solving the surface force based on the flexible body.

A grid generation method and apparatus for an oil reservoir model, and a device, a storage medium and a program product, which relate to the technical field of oil exploration. The method comprises: acquiring an initial oil reservoir grid model, wherein the initial oil reservoir grid model is obtained by performing tetrahedral meshing on an initial oil reservoir model (S201); using a preset layer extraction strategy to extract sub-layers from the initial oil reservoir grid model, so as to generate an initial sub-layer model, wherein the initial sub-layer model is composed of a plurality of sub-layers, and each sub-layer comprises a plurality of triangular mesh elements (S202); using a preset mesh processing strategy to convert the triangular mesh elements in the plurality of sub-layers into rectangular mesh elements, so as to generate a target sub-layer model (S203); and on the basis of a mesh coordinate system and the target sub-layer model, generating a target oil reservoir grid model, wherein grids in the target oil reservoir grid model are all hexahedral grids (S204). The method of the present application improves the grid quality of the oil reservoir model, ensures the accuracy and reliability of subsequent analysis and research based on the oil reservoir grid model, and is applicable to oil reservoir models with non-transmissive faults and overthrust nappe structures, etc.

The application discloses a robust low-approximation-error Cage generation method, relates to the technical field of shape design and generation, and effectively guarantees the robustness of Cage generation and saves a large amount of time overhead through a shape-preserving tetrahedralization algorithm, a tetrahedral mesh subdivision algorithm, a constrained optimization algorithm, an accurate algorithm, a floating-point filtering technology and a space hierarchical structure, a hash structure and the like, and improves the performance of Cage in several important indexes. The algorithm of the application is suitable for general mesh models, for a triangular mesh meeting the requirements, the method can automatically generate a Cage meeting two hard constraint requirements, and the quality of the generated result is better than that of the result generated by the previous method in the indexes of complexity and approximation error.

This invention discloses a method and apparatus for displaying object deformation based on force feedback interaction. When CT data of the object to be interacted with is received, a polygonal bounding volume is constructed using the CT data. The polygonal bounding volume is then tetrahedralized to generate a tetrahedral mesh model. Based on the vertex relationships between tetrahedral units and the unit volume of each tetrahedral unit, the equivalent mass of the mesh particles in each tetrahedral unit is allocated to obtain a soft mesh model. External forces are applied to the soft mesh model in response to control commands. Based on the equivalent mass of the mesh particles and the force corresponding to the applied external force, the particle positions of each tetrahedral unit are iteratively updated to obtain the updated particle positions. The image is rendered based on the updated particle positions, outputting the deformation image corresponding to the object to be interacted with. By combining tetrahedral modeling and iterative updates of particle positions, the accuracy and consistency of force feedback control for interaction between external forces and soft objects are effectively improved.

A high-quality tetrahedral mesh adaptive generation method based on symbolic distance field is disclosed, relating to the fields of computer-aided engineering (CAE) and numerical computation preprocessing. This method calculates the adaptive mesh size based on the gradient of the symbolic distance field, densely samples constraint points near the implicit interface, and generates an initial Delaunay tetrahedral mesh. For this initial mesh, the geometric boundary is restored through edge swapping and point insertion, and the tetrahedral mass ratio is ensured to meet specified values ​​through topology optimization methods of edge swapping and geometric optimization methods of point smoothing. Finally, material properties are assigned based on the symbolic distance field value of the tetrahedral mass center. The method of this invention can improve the geometric accuracy of the tetrahedral mesh, ensure the quality of tetrahedral elements, automatically identify areas near the interface that require refinement, minimize redundant elements while maintaining accuracy, and ensure computational stability.

This application discloses a method, apparatus, device, and medium for generating hexahedral dominant meshes for simulating mechanical structural components of aircraft. It relates to the field of mesh generation technology, including: subdividing a quadrilateral dominant mesh to obtain a triangular mesh; adding the vertices of the surface triangular pieces of the tetrahedral mesh generated from the triangular mesh to a preset queue, and generating target points by traversing the frame of the first vertex in the queue in each direction; querying other position points within the target range, and determining hexahedral edge pairs based on the distance relationship between the target point and other position points; generating a lattice-like tetrahedral mesh based on the triangular mesh and the position field, and determining hexahedral element edges based on the hexahedral edge pairs and the lattice-like tetrahedral mesh; determining right-angled triangular faces based on the selected hexahedral element edges, determining tetrahedral combinations through the right-angled triangular faces, and merging the tetrahedral combinations to generate a hexahedral dominant mesh for simulating mechanical structural components of aircraft. This method rapidly generates high-percentage hexahedral meshes.

The present application is suitable for the field of geophysical exploration technology, and provides a non-structured grid joint inversion method for gravity and magnetic based on equivalent surface source and wave number domain, comprising the following steps: using surface source equivalence to optimize the calculation of gravity and magnetic kernel function matrix; the wave number domain method calculates the kernel function matrix of gravity and magnetic by combining the characteristics of the equivalent surface of non-structured tetrahedral subdivision. In practical application, the present application can more quickly calculate the gravity and magnetic kernel function matrix under non-structured tetrahedral grid subdivision, thereby improving the calculation efficiency of the joint inversion of gravity and magnetic under non-structured tetrahedral grid subdivision, making the joint inversion of gravity and magnetic under non-structured tetrahedral grid subdivision with higher inversion resolution and field source description capability have better development in the fields of large-area mineral resource exploration and fine structure exploration. Through simulation experiment verification, the efficiency improvement of kernel function calculation in the joint inversion of gravity and magnetic under non-structured tetrahedral grid subdivision can reach more than 90%.