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140 results about "Triangular cell" patented technology

A triangular board has been cut into 100 small triangular cells by the lines parallel to its sides. Two cells that share a side are said to be neighbors. In each cell there is a grasshoper.

Method for simulating wide-band electromagnetic scattering property of conductor target

The invention discloses a method for simulating the wide-band electromagnetic scattering property of a conductor target. The method comprises the following steps that the geometric model of the conductor target is built, and mesh generation is conducted on the surface of the conductor target by a curved surface triangle unit; a time domain electric field integral equation of the conductor target is determined; a surface induction current in the time domain electric field integral equation expands through a space CRWG primary function and a time delay primary function; an expanding surface induction current expression is substituted into the time domain electric field integral equation, and then the time domain electric field integral equation in a discrete form is tested in a time and space mode so as to obtain a system impedance matrix equation; singularity integrals are eliminated to obtain a sparse expression of a impedance matrix; the equation of the impedance matrix is solved to determine the distribution of the time domain current of the surface of the conductor target, and wide-band electromagnetic property parameters of the target are obtained according to the distribution of the time domain current so as to finish simulation. The method for simulating the wide-band electromagnetic scattering property of the conductor target has the advantages of being high in simulation precision, little in required time and low in memory consumption, and has wide application prospect.
Owner:NANJING UNIV OF SCI & TECH

Contact judgment method of spherical particles and triangular meshes in discrete element simulation

InactiveCN103235854ASolve the problem of contact judgmentAvoid the problem of separately establishing the contact judgment algorithmSpecial data processing applicationsDiscrete element simulationGraphics
The invention relates to a contact judgment method of spherical particles and triangular meshes in discrete element simulation. The contact judgment method of the spherical particles and the triangular meshes in the discrete element simulation comprises steps of searching neighbor meshes of a target particle to confirm a boundary triangle unit which performs intersecting detection with the target particle; confirming primary contacting information between the target particle and the boundary triangle unit in combination with a symbolic assembly of triangular Voronoi space and center-of-mass coordinates; and judging effectiveness of the primary contacting information, eliminating invalid contacting information and adding the effective contacting information into a contacting linked list to calculate the contact force of particles through a discrete element simulation program. The contact judgment method of the spherical particles and the triangular meshes in the discrete element simulation has the advantages of avoiding respectively building contact judgment algorithms for every kind of basic graphic elements; providing a method for directly positioning an area generating contact to save execution steps of the contact judgment; building judging criteria for eliminating the invalid contact information among multiple contact information; and finally effectively solving the contact judgment problem of the spherical particles and complex geometry boundaries in the discrete element simulation.
Owner:WUHAN UNIV

Conformal cutting layer and path planning method for curved surface 3D printing

The invention discloses a conformal cutting layer and path planning method for curved surface 3D printing. The conformal cutting layer comprises a conformal curved surface cutting layer method and a three-dimensional space path planning method, the conformal curved surface cutting method comprises the following steps that defect inspection and repairing are carried out on a grid model, it is ensured that the outer surface of the model is a two-dimensional flow shape, if the grid surface is not an all-triangular unit, triangular formation is carried out on the grid surface; then regional segmentation is carried out, the printing sequence of each sub-portion and the approximate direction of the sub-layer are determined; the outer surface is converted into point cloud data, and the point cloud is biased inwards; the offset point cloud data is fit to form a triangular mesh surface; and the model is correspondingly divided into a plurality of curved surface layers to obtain a curved surfaceset; and the three-dimensional space path planning method comprises the following steps of checking whether the curved surface in the curved surface set is the two-dimensional flow shape or not, homogenizing the triangular unit, calculating the geodesic distance of each vertex of the grid relative to the designated reference point, extracting equivalent points, fitting to be a contour line, and converting into a G-code to obtain a printing path. According to the conformal cutting layer and path planning method, the special requirements of curved surface printing can be met.
Owner:XI AN JIAOTONG UNIV

Hybrid numerical discretization-based plasticity limit analysis upper-bound method of non-across jointed rock mass

ActiveCN106557608ASimulate the mechanical properties of discontinuous mediaMethod concept is clearDesign optimisation/simulationSpecial data processing applicationsNODALDiscretization
The invention relates to a plasticity limit analysis upper-bound method of a non-across jointed rock mass, and belongs to the field of bearing capacity analysis of the rock mass in rock mechanics. The method comprises the steps of: on the basis of an upper-bound method theory in plasticity limit analysis, discretizing a non-across jointed rock slope by adopting a hybrid element method, namely constructing a kinematically admissible velocity field which simultaneously meets block and structural surface deformation compatibility conditions, plasticity flowing constraint conditions, internal and external power equivalence conditions, block element and triangular element interface plasticity flowing conditions and velocity boundary conditions by adopting a rigid block element discretization rock, a finite element discretization rock bridge, a block element centroid speed and a triangular element node velocity as unknown quantities; and building a linear mathematical programming model of solving an ultimate load of the non-across jointed rock mass, solving the linear mathematical programming model by adopting an interior point algorithm and obtaining an upper-bound solution of the ultimate load of the non-across jointed rock mass. The plasticity limit analysis upper-bound method has the characteristics of clear concepts, high calculation accuracy and the like.
Owner:KUNMING UNIV OF SCI & TECH

Electromechanical integration design method of 65m-aperture large-size reflector antenna structure

InactiveCN102968532AAccurately calculate the phase error of the aperture surfaceRealize comprehensive electromechanical analysisSpecial data processing applicationsElectricityAntenna design
The invention discloses an electromechanical integration design method of a 65m-aperture large-size reflector antenna, mainly aiming at solving the problem in electromechanical integration in large-size antenna design. The electromechanical integration design method comprises the following steps of: obtaining node displacement information after a reflector is distorted on the basis of finite element analysis of an antenna structure; designing a relation between coordinates and coordinate spatial positions after the reflector is distorted according to a node theory, and calculating theoretical coordinates and displacement of centroid points of triangular units; calculating optical path difference of the centroid points of the triangular units and phase errors on the corresponding aperture; projecting the units onto the aperture and calculating far-zone electric field distribution to obtain electrical performance parameters; building an optimization model by taking the structural parameters of the antenna as design variables and optimization of the electrical performance parameter of the antenna as a target; and solving the optimization model by adopting a sequential quadratic programming method to obtain an optimum mechanical electromagnetic comprehensive design scheme, so as to realize the electromechanical integration design of the reflector antenna. The electromechanical integration design method can be used for guiding the structural design of the large-size reflector antenna, and the analysis and the evaluation of the electromechanical comprehensive performance of the antenna under different working conditions.
Owner:XIDIAN UNIV

Water and sand prediction method and system for strong alluvial river based on data assimilation

ActiveCN108334660ASupport regulationGet water level in real timeClimate change adaptationForecastingFluvialLandform
The invention provide a water and sand prediction method and system for a strong alluvial river based on data assimilation. The method particularly comprises the steps of using terrain elevation scatter data obtained by sampling to generate an irregular triangular terrain grid unit; obtaining water-sand information and initial field information of strong alluvial river inlet and outlet boundaries;taking triangular elements of terrain grids as control bodies, discretizing a two-dimensional water-sand model of the strong alluvial river, selecting a solution method for calculation, and obtainingcalculated values of the control bodes; acquiring riverway water and sand state information of the strong alluvial river in real time, establishing a real-time prediction model based on the data assimilation according to the water and sand state information, and obtaining assimilation state variables and parameter variables; finally, using a two-dimensional water and sand data assimilation modelto conduct water and sand prediction on the strong alluvial river. Through the above treatment, the real-time status of water and sand of the strong alluvial river can be effectively predicted, so that water and sand regulation can be regulated, and a basis is provided for flood control and disaster alleviation, water environmental protection and water resource management.
Owner:CHINA INST OF WATER RESOURCES & HYDROPOWER RES

Straining beam cable rod dome structure and construction method thereof

The invention discloses a straining beam cable rod dome structure and a construction method of the straining beam cable rod dome structure. The straining beam cable rod dome structure comprises radial straining beams, circumferential straining beams, stay cables, pressing rods, annular cables, outer pressing rings and staining beam hinges, wherein different shapes and different sizes of triangular units are formed by the radial straining beams and the circumferential straining beams; the triangular units are connected to each other and share one edge to form a straining beam grid; connecting positions of the triangular units stretch downwards to form the pressing rods; each stay cable is connected with the lower ends of the pressing rods arranged at the inner sides of every two adjacent rings and the upper end of the pressing rod arranged at the outer side nearest to the stay cable, or is connected with the lower end of the pressing rod arranged at the outmost ring and the outer pressing rings; the annular cables are connected with the lower ends of the pressing rods in the same ring; the straining beam hinges are arranged at the end parts or the middle parts of the radial straining beams and the circumferential straining beams in the straining beam grid; the straining beam grid, the outer pressing rings, the pressing rods and the stay cables are mutually hinged. The invention also provides the construction method for low-altitude assembly and high-altitude tension forming. The invention provides a space tension structure for paving rigid roof materials, and construction is carried out by adopting an integrated pulling and lifting mechanism expansion method.
Owner:SOUTHEAST UNIV

Multi-claw space-extensible structure

The invention relates to a multi-claw space-extensible structure. The multi-claw space-extensible structure comprises a disc joint, six shear type assembly members, sliding groove guide rails, a rigid connection ring and enclosure rods. The disc joint is located in the center. The six shear type assembly members are symmetrically arranged around the disc joint. Each shear type assembly member is formed by hinging shear type units. Each shear type unit is composed of triangular units. Each triangular unit is formed by connecting three rods end to end. Every two triangular units are hinged mutually at the obtuse angle apex to form the corresponding shear type unit. Every three shear type units are connected vertically to form the corresponding shear type assembly member. A wheel is installed at one end of each shear type assembly member. A hexagon structure is formed by the enclosure rods in an enclosure mode. The rigid connection ring is arranged in the center of the hexagon structure composed of the enclosure rods. The sliding groove guide rails are arranged between the rigid connection ring and six corners of the enclosure rods. The wheels can move back and forth in the sliding groove guide rails. The multi-claw space-extensible structure can be quickly installed anywhere to build a large and stable usage space. The multi-claw space-extensible structure is folded into a small size after being used, and can be detached into rods to be transported and reused. The constituent basic rods are the same, so that mass production is convenient.
Owner:TONGJI UNIV

Simulation method for rapidly extracting transient scattered signals of electric large-size metal cavity target

The invention discloses a simulation method for rapidly extracting transient scattered signals of an electric large-size metal cavity target. The simulation method includes creating a geometric model of the metal cavity target, and performing mesh dissection on the surface of the metal cavity target by a curved-surface triangular unit; determining a time domain integral equation of the metal cavity target; unfolding a surface induced current in the time domain integral equation by a high-order lamination divergence conformal basis function in terms of space and a time and space-time hybrid basis function in terms of time; substituting a surface induced current expression into the time domain integral equation, and testing a time domain electric field integral equation in a discrete form in terms of time and space respectively to acquire a system impedance matrix equation; solving the impedance matrix equation by a time stepping method, determining time domain current distribution on the surface of the conductor target, and acquiring broadband electromagnetic characteristic parameters of the target according to time domain current distribution to complete simulation. The method has the advantages of high simulation accuracy, less time used and low memory consumption, thereby having a broad application prospect.
Owner:NANJING UNIV OF SCI & TECH

Meshless method for analyzing excavation and support of tunnel

The invention relates to the technical field of tunnels, in particular to a meshless method for analyzing excavation and support of a tunnel. The method comprises the following steps of (1) starting CAE of ABQUS, and establishing a two-dimensional model of a chamber; (2) dividing a triangular cell model; (3) outputting a model file, Job-1. Inp; (4) starting MATLAB, opening a main program file, Main_Program. M, of MFVM; (5) reading the model file, Job-1. inp; (6) generating node information; (7) using the MFVM to calculate the initial ground stress of surrounding rocks; (8) calculating a stress field and a displacement field in the first step of the excavation. The method has the advantages that since an approximation function of the meshless method has no dependence on meshes, the difficulty caused by grid distortion is reduced, interface connection with CAD software can be achieved more easily, and the method is suitable for solving large-scale scientific and engineering problems; besides, since the adaptability of the meshless method is very strong, node position information rather than mesh information is needed in the pretreatment of the meshless method, and a complex three-dimensional structure can be analyzed easily; moreover, an obtained graph of meshless calculation is smooth and continuous, so no stress smoothing is needed.
Owner:SICHUAN UNIV

2.5-dimensional viscoelastic wave numerical simulation method and apparatus in frequency domain

Embodiments of the present invention provide a 2.5-dimensional viscoelastic wave numerical simulation method and apparatus in the frequency domain. The method comprises: establishing a 2.5-dimensionalviscoelastic wave equation in the frequency domain; determining an equivalent integral weak form of the 2.5-dimensional viscoelastic wave equation in the frequency domain; obtaining a finite elementcontrol equation by using the discrete of bilinear triangular elements; loading 3D point sources in the frequency domain; loading the stiffness to weaken the absorption boundary condition; determininga wavenumber sampling strategy, wherein the finite element control equation is large sparse linear equations, and a direct solution method is used to solve the equations to obtain a frequency-wavenumber domain wave field; and using a complex Simpson numerical integration method to approximate the spatial inverse Fourier transform to obtain a three-dimensional viscoelastic wave field in the frequency domain. The present invention provides an accurate forward modeling method for 2.5-dimensional viscoelastic wave multi-scale full waveform inversion, and the method can adapt to any undulating surface complex medium, has a good absorption effect of the absorption boundary condition, and has high calculation efficiency.
Owner:赵建国 +2

Method for rapidly converting spherical triangle discretization grid codes into geographic longitude and latitude coordinates

The invention discloses a method for rapidly converting spherical triangle discretization grid codes into geographic longitude and latitude coordinates. The method comprises the following steps of inputting grid codes, and converting the grid codes into rank numbers; according to dissection layers of the codes, determining a control dissection layer; in a stage lower than the control dissection layer, adopting a recursive approaching method for determining a control triangular unit corresponding to the grid codes on the control dissection layer and the rank number of the target code cell inside the control triangle; when the control dissection layer is converted, adopting a direct mapping method for directly dividing the control triangle into grids in a halving mode, and then finding a target triangular cell according to the rank number inside the control triangle; calculating coordinates of the central point of the target triangular cell, converting the rectangular coordinates into longitude and latitude coordinates, and outputting the coordinates to complete conversion. The efficiency of converting spherical triangle discretization grid codes into geographic longitude and latitude coordinates can be obviously improved, and the algorithm time complexity is increased along with the dissection layers and increased linearly.
Owner:NANJING NORMAL UNIVERSITY

Maritime structure for laying the foundations of buildings, installations and wind turbines by means of gravity in a marine environment

The invention relates to a maritime structure for laying the foundations of buildings, installations or wind turbines by means of gravity in a marine environment, which has significant advantages for constructing, transporting, positioning and operating same, owing to the novel features introduced into the design thereof in comparison with existing types. The structure comprises a base in the shape of a chamfered equilateral triangle, having a sufficient height to optimise navigability, the base being formed by a frame of vertical walls that form hexagonal or triangular cells closed at the ends by a lower slab and an upper slab, and three closed towers having a regular hexagonal or circular cross section which are located in the corners of the base. The structure can be towed, completely installed, with a wind turbine or superstructure that same supports, and has low initial draft, high naval stability and low resistance to movement. The anchoring process is performed by using gravity to ballast the cells with seawater, without needing any additional means, auxiliary large-capacity vessels or floating elements external to the structure itself. The structure can be positioned as a gravity foundation at a depth of 20 to 50 meters and can be re-floated to be transferred whole again to a port for dismantling.
Owner:BERIDI MARITIME SL
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