284 results about "Tetrahedron" patented technology

The invention discloses a three-dimensional unstructured grid adaptive refinement method and system based on machine learning, and belongs to the field of machine learning, partial differential equation solving and computational fluid mechanics simulation. Residual errors of a fluid control equation are used as a novel error indicator and a refinement criterion, imprecise flow field data and the fluid control equation are obtained by fusing coarse grids of simulation flow through a physical information neural network, and the total residual errors of the equations are conveniently calculated by using automatic differentiation after training is completed. Therefore, the coarse grid units with relatively high residual errors can be adaptively marked and refined. By matching an h-refinement scheme, Delaunay tetrahedron subdivision is executed after vertexes are strategically inserted to maintain the quality of the refined grid. According to the method, any numerical solver can be flexibly matched to carry out grid adaptive refinement, so that various typical flow problems can be solved with high precision. The method achieves better balance between calculation precision and the number of grids, and has the advantages of being simple, convenient, high in compatibility and universality and the like.

The invention provides a tunnel surrounding rock dynamic grading and blasting parameter optimization method and system, and relates to the technical field of data processing.The method comprises the steps that geological parameters of a current tunnel face are collected in real time through a multi-source sensing system deployed on the tunnel face; based on the acquired geological parameters, identifying a plurality of characteristic sampling points with geological representativeness in a tunnel face spatial domain; four non-coplanar feature sampling points are selected to construct an initial tetrahedron, the point, farthest from the surface of the current convex hull, in the remaining points is included in sequence through an iterative extension method, the surface of the convex hull is recalculated till all the feature sampling points are enveloped, and a convex polyhedron evaluation area boundary is formed. According to the invention, data full-process connection and function collaboration can be realized.

The invention relates to the technical field of geophysical exploration, and particularly provides a three-dimensional finite element transient electromagnetic forward modeling calculation method based on an iterative solution method.The method comprises the steps that tetrahedron space discretization is carried out based on a vector finite element method, and an electric field is given to six edges of a space tetrahedron; constructing a back-pushing Euler finite element equation set, and assembling a linear system formed by a large sparse matrix based on the equation set; performing iterative solution on the linear system based on an FGMRES algorithm to obtain an electric field value corresponding to a spatial tetrahedron unit edge; optimizing a spatial tetrahedral mesh based on a quadratic nesting method, and optimizing a time step length based on a third-order backward Euler difference format; a grid pre-encryption method is adopted, the calculation error of iterative solution is reduced, a region decomposition method is used for achieving parallel calculation, and the calculation efficiency is greatly improved. According to the method, the requirements of high precision and high efficiency in three-dimensional transient electromagnetic forward modeling calculation can be met, and an advanced calculation tool is provided for resource exploration in a complex geological environment.

The invention provides a grid quality optimization method, computer equipment, a program product and a storage medium. The method comprises the steps that an initial grid is acquired, the initial grid is converted into a built-in data structure, and a grid object is acquired, wherein the grid object comprises a node set, a tetrahedron set and topological adjacency information; traversing each grid node of the grid object, and adding a constraint condition for each grid node; regarding the discretized three-dimensional grid as a hyperelastic body, and calculating the energy of the current grid for each tetrahedron unit in the grid object through a hyperelastic model; performing iterative calculation on the energy minimum value of the current grid according to the constraint condition, and applying random disturbance after each N iterations until a convergence threshold value or the maximum number of iterations is reached; and the grid corresponding to the minimum energy value is output as the optimal grid. According to the scheme, the overall quality of the grid can be effectively improved, and the boundary retention capability and the restoration capability of the degraded unit are enhanced, so that the simulation quality is improved.

The invention provides a finite element analysis method for a competition-level site cross-country motorcycle frame, and belongs to the technical field of crossing of computer-aided engineering and vehicle structure design. The method comprises the following steps: performing parametric modeling on a frame main bearing structure based on CATIA software, and simplifying non-functional characteristics; importing the model into ANSYS Workbench, generating a high-precision finite element model by adopting a grid division strategy of mixing tetrahedron and hexahedron units, and considering the calculation efficiency and precision; defining material characteristics; a limit load working condition is simulated through statics analysis, a displacement cloud picture and a stress cloud picture are combined to be compared with the yield strength of a material, and topological optimization is conducted on a weak area; meanwhile, the inherent frequency of the frame is extracted through modal analysis, and the resonance risk is avoided. According to the method, statics analysis and modal analysis are carried out on the frame through cross-platform co-simulation, the structural reliability is evaluated, and the method is suitable for efficient development and performance optimization of competition-level cross-country motorcycle frames.

The invention provides a thermal simulation processing method, device and equipment for a printed circuit board and a storage medium, and relates to the technical field of simulation processing, and the method comprises the steps: building an electronic equipment geometric model, dividing the electronic equipment geometric model into a plurality of tetrahedron units, setting material parameters, and generating an electronic equipment grid model; rasterizing a pre-established geometric model of the printed circuit board to obtain a plurality of grid subunits, and calculating equivalent material parameters of each grid subunit according to actual circuit data of the printed circuit board; screening out a plurality of first tetrahedron units in the electronic equipment grid model; mapping the first tetrahedron units to corresponding positions in the rasterized model to obtain equivalent material parameters of each first tetrahedron unit; updating material parameters of a printed circuit board area in the electronic equipment grid model; and performing thermal simulation processing, and drawing a temperature distribution diagram of the printed circuit board. According to the invention, high-precision temperature distribution of the printed circuit board can be obtained.

The invention belongs to the technical field of quantum precision sensing, and particularly relates to an NV color center magnetic detection or temperature measurement method based on a zero field splitting coefficient, which is characterized in that a hypothetical magnetic field vector is calculated according to lattice structure characteristics of a diamond regular tetrahedron, and the zero field splitting coefficient is calculated according to the amplitude of the vector. Frequency deviation introduced by the transverse magnetic field is fully considered, and the accuracy is improved on the basis of the steps. Compared with an existing method, the calculated zero field splitting coefficient is more accurate, an error analysis method is provided, and magnetic field measurement or temperature measurement can be achieved through a more accurate D value by means of the method.

A method for identifying and calculating the volume of over- and under-excavation in tunnels based on laser point clouds belongs to the field of intelligent tunnel construction and blasting quality assessment technology. Technical solution: The scanned point cloud data is denoised; a design contour point cloud is generated and aligned with the centerline of the actual excavated tunnel; the actual collected tunnel excavation point cloud and the design contour point cloud are Delaunay tetrahedralized; the actual tunnel point cloud is traversed, and the vector dot product formed between the point cloud and the triangular sides of the convex hull is calculated; over- and under-excavation areas are identified; a polyhedron is constructed from the design contour point cloud and the actual excavated area point cloud constituting the area; the polyhedron is divided into quadrilaterals, and the volume of each quadrilateral is calculated, thereby calculating the volume of each over- and under-excavation area. Beneficial effects: This invention can quickly measure over- and under-excavation areas and quantities that are difficult to calculate in tunnel blasting quality assessment, and can replace cumbersome and time-consuming total station and manual measurement methods; this method has the advantages of high precision, high efficiency, and high flexibility.

The invention relates to an extraterrestrial celestial body boundary-free scene three-dimensional reconstruction method based on a Gaussian radiation field, and the method comprises the steps: extracting visual features of an input image, and obtaining internal parameters, external parameters and scene sparse point cloud of a camera through feature matching and cluster adjustment; an expanded dense point cloud is calculated according to a light plane intersection mode, a series of three-dimensional Gaussian distributions are constructed, and pixel colors in a given visual angle direction are rendered in a rasterization mode; aiming at a rendering result, guiding a Gaussian position to be accurately close to a scene surface by utilizing pre-estimated depth prior in an optimization process; a scene surface is accurately captured in combination with an explicit and implicit model joint representation mode; and rebuilding a fine and complete three-dimensional mesh model on the surface of the extraterrestrial celestial body by using a marching tetrahedron algorithm according to an optimization result. According to the method, fine three-dimensional reconstruction of the surface of the extraterrestrial celestial body in a boundary-free scene can be realized, the modeling capability of a Gaussian radiation field in the boundary-free scene is enhanced, and the precision and integrity of three-dimensional reconstruction of the surface of the extraterrestrial celestial body are improved.

The invention discloses a tunnel back break identification and volume calculation method based on laser point cloud, and belongs to the technical field of tunnel intelligent construction and blasting quality evaluation. According to the technical scheme, point cloud data obtained through scanning are denoised; generating a design contour point cloud and aligning the design contour point cloud with an actual excavation tunnel center line; performing Delaunay tetrahedron on the actually acquired tunnel excavation point cloud and the designed contour point cloud; traversing the actual point cloud of the tunnel, and calculating a vector dot product formed between the point cloud and the triangular edge of the convex hull patch; judging an over-excavation and under-excavation area; and constructing a polyhedron by using the design contour point cloud and the actual excavation area point cloud which form the area, dividing the polyhedron into quadrangles, and calculating the volume of each quadrangle, thereby calculating the volume of each over-excavation and under-excavation area. The method has the beneficial effects that the over-excavation and under-excavation areas and the over-excavation and under-excavation amount which are difficult to calculate in tunnel blasting quality evaluation can be rapidly measured, and a tedious and time-consuming total station and a manual measurement method can be replaced; the method has the advantages of high precision, high efficiency, high flexibility and the like.

The invention relates to an MVP formula-based edge element magnetostatic high-precision calculation method for smooth edges, and the method comprises the steps: dividing grid data into a plurality of polyhedral smooth regions with corresponding edges as centers according to the edges in the grid data; the polyhedral smooth domain is formed by surrounding corresponding edges by nodes, body centers and face centers of tetrahedron units in the grid data; calculating the vector shape function gradient of the corresponding edge based on the vector shape function of each tetrahedron unit in the polyhedral smooth domain corresponding to the edge; constructing a static magnetic field equation based on an MVP formula and coulomb specifications, and rewriting the static magnetic field equation according to the vector shape function gradient of each edge and a Galerkin method to obtain a system equation of a static magnetic field; further rewriting the system equation of the static magnetic field into a Newton iteration linear equation; and iteratively solving the Newton iteration linear equation by adopting a Newton iteration method until convergence to obtain the magnetic vector position in the static magnetic field. According to the method, the requirements of high calculation precision and stability of the engineering static magnetic field problem are met.

The invention discloses a soft tissue cutting simulation method which comprises the steps that a soft tissue model and a scalpel model are obtained, and the soft tissue model comprises a plurality of vertexes and a tetrahedron defined by the vertexes; determining a collision point according to the collision detection result and determining the stage of the cutting process of the tetrahedron in the current frame, wherein the stage comprises a cutting stage and a cutting completion stage; determining a first constraint function of the collision point according to the collision point; or, in the cutting completion stage, performing fine segmentation on the collision tetrahedron to obtain a plurality of sub-tetrahedrons, and determining a second constraint function of the vertexes in the plurality of sub-tetrahedrons according to the vertexes of the plurality of sub-tetrahedrons; based on the first constraint function or the second constraint function, using position dynamics to calculate and obtain model parameters of the soft tissue in the current frame; and displaying the soft tissue according to the model parameters of the soft tissue in the current frame.

The invention relates to the technical field of electromagnetic simulation, in particular to a W-band antenna pointing angle simulation analysis method, which comprises the following steps: acquiring the size of a W-band antenna and the form of a radiation unit, extracting main lobe curvature and feed matching characteristics, identifying a main lobe edge interference path, and adjusting a reflection phase to form a dynamic reflectivity boundary. Dividing tetrahedron and hexahedron grids to evaluate polarization consistency, optimizing a field intensity relationship between a main lobe and a side lobe, screening an angle interval, and obtaining a directional angle correction parameter. According to the invention, the specific size and form of the antenna are acquired, the curvature distribution of the main lobe coverage area and the matching relation with the feed structure are deeply analyzed, and the reflection intensity difference between the main lobe path and the side lobe path is monitored, so that the pointing precision and the coverage efficiency of the antenna are effectively improved; according to the antenna design, the performance is ensured, the specific area can be optimized, and the predictability and the stability of the antenna performance are remarkably improved.

The invention discloses a three-dimensional model generation method and system based on fractional distillation sampling, and the method comprises the steps: obtaining an original image, and enabling the original image to be aligned with a preset tetrahedral ball grid, and obtaining a first model; according to a fractional distillation sampling algorithm and the noise residual error, a gradient updating direction is generated through iterative calculation, the second model is adjusted according to the gradient updating direction to obtain a third model until the number of iterations is reached, and the current third model is output as a final model; updating the first model to the current third model after the third model is obtained each time; wherein the noise residual error is obtained by performing noise prediction and calculation on the first rendering image injected with the random noise according to a frozen two-dimensional image generation model; the first rendering graph is obtained by rendering the first model according to a micro rendering algorithm; the second model is obtained by adjusting the current first model according to the rendering loss between the first rendering graph and the original image. According to the method, the problems that local distortion easily occurs and deformation is uncontrollable when the three-dimensional model is generated are solved.

In various examples, a deep three-dimensional (3D) conditional generative model is implemented that can synthesize high resolution 3D shapes using simple guides—such as coarse voxels, point clouds, etc.—by marrying implicit and explicit 3D representations into a hybrid 3D representation. The present approach may directly optimize for the reconstructed surface, allowing for the synthesis of finer geometric details with fewer artifacts. The systems and methods described herein may use a deformable tetrahedral grid that encodes a discretized signed distance function (SDF) and a differentiable marching tetrahedral layer that converts the implicit SDF representation to an explicit surface mesh representation. This combination allows joint optimization of the surface geometry and topology as well as generation of the hierarchy of subdivisions using reconstruction and adversarial losses defined explicitly on the surface mesh.

Golf balls having a low surface coverage dimple pattern arranged in a tetrahedral layout are disclosed. The dimple pattern has four substantially identical dimple sections. The dimples in each of the four dimple sections have at least three different dimple diameters, including a minimum dimple diameter, a maximum dimple diameter, and an additional (third) dimple diameter, where the additional dimple diameter substantially contributes to the overall surface coverage of the dimple pattern. The resulting dimple pattern has a low dimple surface coverage and high diameter disparities among the dimples, which helps to reduce the flight of the golf ball while providing improved aerodynamic consistency.

This invention discloses a finite element design and analysis method for a novel structural piezoelectric composite material. The method includes the following steps: extracting the zero level set surface based on the spatial structural equation to create the geometric shapes of a 3D TPMS shell structure, including Schwarz P, Gyroid, Neovius, and Diamond structures; using Matlab to define the frame volume fraction of the geometric shapes and control the unit node information in the 3D TPMS shell structure model; generating the 3D TPMS shell structure model as an inp file, importing the inp file into Abaqus to generate hexahedral elements; using Rhino to smooth the surface of the hexahedral elements, exporting the STL file, and performing remeshing in Hypermesh to convert the hexahedral elements into tetrahedral elements; adding periodic boundary conditions to the tetrahedral element mesh and performing numerical simulation to obtain the TPMS shell structure composite material model. The novel TPMS shell structure piezoelectric composite material designed by this method significantly improves piezoelectric performance compared to existing piezoelectric composite materials.

The invention relates to the technical field of data processing, and discloses a multi-source data difference attribution system and method based on tensor decomposition, and the method comprises the steps: obtaining an original engineering quantity list file, and then carrying out decoupling to generate a standardized list item text sequence and an initial value set, constructing unit prices to form a tetrahedral geometric model set, mapping the tetrahedral geometric model set to a holographic feature vector space, and generating a multi-dimensional list feature vector set; constructing a standard cost reference vector field, identifying a difference vector set and generating a visual cost difference topological data model; a natural language query instruction is responded, a target difference attribution tensor is locked, a logic verification chain is constructed, and an intelligent diagnosis report is output; according to the method, a computable logic distance is established in multi-source heterogeneous data by reversely reconstructing a high-dimensional price-rate feature space, so that the problem of attribution blocking caused by dimension collapse in traditional cost auditing is effectively solved, and accurate traceability and compliance automatic diagnosis of cost differences are realized.

Golf balls having a dimple pattern arranged in a tetrahedral layout are disclosed. The dimple pattern has four substantially identical dimple sections, where each dimple section is defined by a spherical triangle. The dimples in each of the four dimple sections have at least two different dimple diameters including a minimum dimple diameter and a maximum dimple diameter. The resulting dimple pattern has a low dimple surface coverage and high dimple diameter disparity which helps to reduce the flight of the golf ball while providing improved aerodynamic consistency.

The invention provides a grid encryption method, computer equipment, a storage medium and a program product. The grid encryption method comprises the following steps: acquiring an input initial grid, an input frequency, an input maximum iteration frequency and a preset S parameter change threshold value; reading an initial grid and carrying out grid boundary identification; a finite element matrix is constructed and solved, and an S parameter matrix and a current S parameter variable quantity during current iteration are obtained; when the current S parameter variation is greater than a preset S parameter variation threshold, constructing a mapping relationship between four surfaces of each tetrahedron and the adjacent tetrahedron; calculating the body charge, the body current density, the surface charge and the surface current density of each tetrahedron; and calculating the total error of each tetrahedron, and calibrating and encrypting the tetrahedrons needing to be encrypted. According to the scheme, by introducing the body unit error index and the surface unit error index, the grid region which has the greatest influence on the S parameter can be identified, and local encryption is carried out on the grid region, so that the computing resource consumption is reduced, and the solving precision is improved.

The invention discloses a virtual operation simulation method based on grid adaptive cutting and subdivision, and the method comprises the steps: firstly, carrying out the tetrahedron of an input cut object, and recording the position of a scalpel to form a cutting surface; secondly, constructing a bounding box and a bsp tree A, marking a splicing surface and a simulated surface, and generating a common cutting line by utilizing triangulation to obtain a simulated cutting surface; then marking movable vertexes and immovable vertexes, solving the positions of new vertexes according to Hooke's law, moving the vertexes to simulate the cut shape, performing re-tetrahedron and bsp subdivision on a local area, and generating a bsp tree B and A combination; and finally, traversing all bsp nodes, carrying out tetrahedron on non-tetrahedron nodes by utilizing the gravity center of the non-tetrahedron, completing simulated cutting, and carrying out optimization. According to the method, the cut object is precisely cut, the precision of the cutting plane is improved, and the stability and accuracy of cutting simulation are guaranteed.

The invention discloses a compact quaternary hydrophone array and a sound source localization method, the compact quaternary hydrophone array comprises a regular tetrahedron framework and a support device, and the regular tetrahedron framework is arranged on the support device; the regular tetrahedron framework comprises a regular tetrahedron composed of a plurality of square rigid supports, hydrophone supports arranged at the four vertexes of the regular tetrahedron, and hydrophones arranged on the hydrophone supports. The compact quaternary hydrophone array provided by the invention is simple in structure and convenient to assemble, and can also reduce the influence of sound wave scattering on a space sound field and improve the sound source positioning precision.

The invention provides an intelligent operation and maintenance method and system based on an intelligent cabinet, and relates to the technical field of intelligent operation and maintenance, a three-dimensional finite element model of the intelligent cabinet is obtained by performing finite element analysis on operation parameters and axis state information of the intelligent cabinet, and a node information matrix is determined based on a discretization structure of a tetrahedron unit of the intelligent cabinet; performing hierarchical clustering on the node information matrix to obtain a clustering center set, and performing similarity response on the three-dimensional finite element model through the clustering center set to obtain a response value of each clustering center; the historical response data and all the response values of the intelligent cabinet construct a mechanical response field of the intelligent cabinet, and a digital twinborn model of the intelligent cabinet is constructed based on a deep neural network; the operation and maintenance instruction of the intelligent cabinet is determined according to the mechanical response field and the digital twinborn model, and then the operation and maintenance instruction controls the intelligent cabinet to perform remote operation and maintenance, so that precise twinborn prediction can be performed on the operation state of the intelligent cabinet to realize intelligent operation and maintenance of the server cabinet.

The invention provides a variable wing-shaped composite wing vertical take-off and landing unmanned aerial vehicle which is characterized in that a fuselage structure is a spatial tetrahedral structure, and the tetrahedral structure comprises a triangular bottom surface structure and a spatial triangular pyramid structure located above the triangular bottom surface structure; three bottom edges of the spatial triangular pyramid structure are three edges of the triangular bottom surface structure; the lift structure is arranged at the top of the straight line where the gravity center of the fuselage structure is located; the thrust structure provides thrust for flight of the unmanned aerial vehicle; the folding and unfolding horizontal wings can be folded and unfolded. Therefore, gravity center stability and structural strength are guaranteed through the space tetrahedron fuselage structure, the lift force structure provides lift force during vertical take-off and landing, the horizontal wings are folded to reduce interference, and the lift force structure is inclined to cooperate with the unfolded horizontal wings to improve aerodynamic efficiency during horizontal flight. The folding and unfolding horizontal wing capable of being dynamically adjusted can prevent attitude instability by actively adjusting pneumatic layout in low-altitude turbulent flow.

The invention provides a finite element modeling method and device for a strut type undercarriage structure, and the method comprises the steps: 1, building finite element models of a wheel fork, an inner cylinder, an outer cylinder and an anti-torsion arm of an undercarriage in a preset coordinate system through employing a tetrahedron entity unit TET10; and 2, connecting finite element models of a wheel fork, an inner cylinder, an outer cylinder and an anti-torsion arm by adopting a finite rigid body element, and setting the degree of freedom of a steel body element to obtain a finite element model of the undercarriage structure. More accurate component stress and connection load can be obtained, weak points of all components can be obtained, and weight reduction optimization work can be better carried out; compared with an engineering algorithm, the calculation accuracy is improved, and the time is saved; the key points and the method for finite element modeling of the undercarriage structure are provided, and the method is suitable for strength analysis of various strut type undercarriages.

The utility model discloses a kind of splicing ornaments, belong to ornament technical field, including multiple splicing modules, the splicing module is triangle or square, its edge is equipped with zip structure, and splicing module can be connected by the zip structure between it. Through different combination mode, the splicing module can be assembled to form the ornament of tetrahedron structure, hexahedron structure or four pyramid structure. The splicing module is equipped with hole, for wearing external chain to realize the function of suspension. The utility model connects between splicing module by zip structure, with the characteristics of convenient splicing, combination form is various.

This item is an ornament with a strap attached, and can be placed on a table or attached to the owner's personal belongings. The outer surface of the main body, which resembles a tetrahedron with edges indicated by solid lines in each figure, is basically a tetrahedron and is formed entirely from a transparent thin film or thin plate-like material. The inside of the outer surface of the main body is hollow, and a main decorative part imitating various characters is disposed within this hollow. The main decorative part is suspended via a chain member from a ring member that is engaged with a pair of holes opening at the top of the outer surface of the main body, and a strap metal fitting equipped with a flat tag is attached to the ring member.

A logic cube with changeable tiles is presented. The tiles which can be fit on the logic cube, have indicia in well-defined positions and orientations such that the resulting solid is an exact but larger replica of the initial logic cube. The tiles are such that they can be easily fit or removed, and do not fall off with the movement of the logic cube. They also do not obstruct the functionality of the logic cube. Other geometric shapes such as tetrahedron and dodecahedron and sizes other than 3×3×3 may be used.

Methods and apparatus for acquiring and encoding omnidirectional surround sound are described herein. An exemplary omnidirectional surround microphone may include a first microphone capsule oriented substantially toward a first vertex of a conceptual tetrahedron, a second microphone capsule oriented substantially toward a second vertex of the conceptual tetrahedron, a third microphone capsule oriented substantially toward a third vertex of the conceptual tetrahedron and a fourth microphone capsule oriented substantially toward a fourth vertex of the conceptual tetrahedron.

The invention discloses a welding robot hand-eye calibration method based on a tetrahedron model, which comprises the following steps: S1, preparing the tetrahedron model, carrying out laser scanning on a tetrahedron on a welding robot, and obtaining point cloud data of the tetrahedron through a nine-point method; s2, performing coarse registration according to the standard tetrahedron model point cloud data, and calculating to obtain T1; s3, according to a coarse registration result, performing fine registration calculation to obtain T2; and S4, performing combined calculation on the coarse registration result and the fine registration result to obtain a final pose matrix T3. According to the method, through the artificially customized tetrahedron with a specific shape and the optimization step of combining the coarse registration method and the fine registration method, the initial value is given by using the coarse registration method, then the initial value is used as input, the calculation of the rotation matrix is completed by using the fine registration method, complex plane extraction is not needed, the artificial participation is less, and the calculation efficiency is high. And the applicability is high, errors caused by a plane extraction step are avoided, high measurement precision is ensured, and a calibration result is more reliable.