34 results about "2D geometric model" patented technology

The invention relates to an automatic grid density generation method applicable to finite element analysis during a forging process. According to the boundary curvature, geometric property, the distribution of field variables (such as stress, strain, strain rate and temperature and the like) and requirement for the number of division units of a geometric model as well as a user-designated density window, the method is capable of automatically generating optimized and reasonable grid density distribution and a gird model, effectively controlling the number of the grid units generated eventually and combing various grid generation methods so as to generate an adaptive finite-element grid model and greatly improve the analysis efficiency and precision of numerical analysis methods such as like a finite element method. The method is applicable to the automatic gird density generation of not only 2D geometric models but also 3D geometric models. In addition, the method is applicable to not only finite-element grid density generation but also cases that initial grid division and grid re-division are needed when finite volume and finite difference are used to analyze other engineering problems.

The invention discloses a method for analyzing influences, caused by beaded-shaped karst, on pile foundation stressed deformation. The method comprises the following steps: A, selecting finite element numerical value simulation software; B, establishing an axisymmetric two-dimensional geometric model according to on-site geological researches; C, carrying out grid division, selecting a constitutive model, and setting boundary conditions and material parameters; D, additionally arranging a contact unit between a pile foundation and a stratum; E, killing a pile foundation material unit, and simulating a stress state and settlement deformation of the stratum under the effect of gravity; F, activating the pile foundation material unit and simulating pile foundation construction; G, applying pile foundation top load and simulating the effect of external load; H, discounting an elastic modulus of fillings in a karst cave, and simulating a secondary consolidation settlement process of the soft fillings in the karst cave after disturbance; and I, obtaining stressed deformation results of the stratum and the pile foundation through a post-processing program. The method disclosed in the invention is feasible, simple and convenient to operate and efficient in calculation, has the effect of satisfying the design and construction of pile foundations in karst areas, and has great importance for the design and construction of building pile foundations in the karst areas.

The invention discloses a flexible PCB structure design method based on wet chemical etching joint simulation. The method comprises the following steps: firstly, presetting a production parameter data set according to actual production data; then, according to the data set, using multi-physics field finite element simulation software to construct a flexible PCB equivalent two-dimensional geometric model, establishing a multi-physics field simulation model, and completing setting of material attributes, boundary conditions, initial conditions and grids to complete establishment of the simulation model; then calling and iteratively simulating the simulation model by using a model interaction algorithm and a GA according to a preset optimization target and a code parameter set, and curing and reserving optimized structure parameters obtained by simulation for production design. According to the invention, simulation calculation of the structure parameters is carried out through simulation, the structure parameters which are more targeted and meet the actual design requirement can be obtained more intelligently in combination with the GA algorithm, and the method is a scientific design method which can greatly reduce the design cost of a test mode and improve the design time efficiency.

The invention discloses a method for simulating a wet chemical etching process of a flexible PCB (Printed Circuit Board). The method mainly introduces a method for simulating the running speed of a linear body, the spraying pressure and the concentration of etching liquid in the etching process by establishing a model. The specific implementation process is as follows: constructing a two-dimensional geometric model of a copper substrate to be processed by using multi-physical field coupling simulation software COMSOL Multiphysics, setting corresponding simulation parameters and boundary conditions, obtaining a simulation result through simulation calculation, and finally, carrying out experiment verification on the feasibility of simulation by using known production data. According to the method, the material and time cost for researching the wet chemical etching process of the flexible PCB in an experimental mode can be greatly reduced, and the problems existing in the actual production process can be analyzed in a targeted mode.

The invention belongs to the technical field of structural design, and particularly relates to a dimensionality reduction design method for a specially-shaped curved surface functional structure. According to the technical scheme, a dimensionality reduction design idea is utilized, a three-dimensional special-shaped curved surface appearance structure is expanded into a two-dimensional equivalentgeometric model, parameterization design of a functional unit is carried out in the two-dimensional geometric model, finally, the two-dimensional model containing a functional unit configuration is mapped back to an original curved surface, and a three-dimensional special-shaped curved surface functional structure is formed. The method has the advantages that the problem of overlarge calculation amount of directly carrying out functional unit configuration design in the three-dimensional special-shaped curved surface structure on the airplane is solved, an efficient design approach is providedfor special-shaped curved surface functional structure configuration design, meanwhile, the design difficulty and calculation requirements are reduced, and the method is suitable for functional structure design of the special-shaped curved surface appearance.

The invention discloses a finite element calculation method for continuous casting solidification heat transfer of a fillet square billet, and relates to the technical field of steel continuous casting. The method comprises the following steps: establishing a two-dimensional geometric model of the rounded square billet according to the section size of the rounded square billet; performing grid division on the two-dimensional geometric model of the rounded square billet, and establishing a two-dimensional finite element model of the rounded square billet; establishing a two-dimensional finite element solidification heat transfer model of the rounded-corner square billet aiming at the problem of continuous casting solidification heat transfer of the rounded-corner square billet; and calculating the temperature field change in the continuous casting process by using the two-dimensional finite element solidification heat transfer model of the rounded square billet. According to the method, the special situation that square billets usually have fillets in actual production is fully considered, triangular units are adopted, when grids are dense enough, any curve of the boundary of a region can be simulated and calculated through segmented straight lines on the boundary, and the calculation precision is guaranteed to a certain degree; a finite element method is adopted for calculation, and the calculation precision is improved; proper boundary conditions are selected according to different cold areas, and the full-process solidification heat transfer of the continuous casting production of the rounded square billets is simulated more accurately.

A hot reflux process analysis method comprises the following steps of 1, establishing an overall three-dimensional geometric model, the overall geometric model being a cuboid, the surface of the overall geometric model being a calculation boundary, and the interior of the overall geometric model being a calculation domain; 2, taking one part of the overall geometric model as a local research object, taking one section of the local three-dimensional geometric model, and establishing a two-dimensional geometric model; 3, performing mesh generation on the two-dimensional geometric model by usingpreprocessing software, and setting preliminary boundary conditions and fluid regions; 4, importing the grid into FLUENT software, defining a calculation model for simulating and calculating a hot reflux process, and determining a control equation for solving and calculating the process; 5, setting boundary conditions of the simulation model and solving a numerical calculation method of a controlequation; and 6, carrying out iterative computation on the control equation. Based on the method, the hot reflux forming process can be analyzed and evaluated, and corresponding parameters of actual production can be better controlled to achieve more accurate manufacturing.

The invention discloses a finite element calculation method for continuous casting solidification heat transfer of a beam blank, and relates to the technical field of steel continuous casting. The method comprises the following steps: establishing a 1 / 2 beam blank two-dimensional geometric model according to the section size of a beam blank; performing grid division on the two-dimensional geometric model of the 1 / 2 special-shaped blank, and establishing a two-dimensional finite element model of the 1 / 2 special-shaped blank; a 1 / 2 beam blank two-dimensional finite element solidification heat transfer model is established for the beam blank continuous casting solidification heat transfer problem; and calculating the temperature field change in the continuous casting process by using the two-dimensional finite element solidification heat transfer model of the 1 / 2 special-shaped blank. According to the method, the complex section shape of the special-shaped blank is fully considered, the triangular units and the general quadrilateral units are adopted, and the actual cross section of the special-shaped blank can be better simulated; appropriate boundary conditions are selected according to different cold areas, the full-process solidification heat transfer of the beam blank continuous casting production is more accurately simulated, and the temperature field change in the beam blank continuous casting process is described.

The invention provides a simulation method and system for a zinc oxide arrester. The method comprises the following steps: acquiring parameter data of the zinc oxide arrester; constructing a two-dimensional geometric model of the zinc oxide arrester according to the obtained parameter data; assigning the material characteristic parameters of each part of the two-dimensional geometric model; obtaining a two-dimensional electromagnetic simulation model according to the assigned two-dimensional geometric model, and performing analogue simulation on the zinc oxide arrester according to the two-dimensional electromagnetic simulation model; according to the method, the electromagnetic characteristics in the time domain range of the lightning arrester can be simulated and solved, the problem that an existing modeling method cannot analyze and calculate the instantaneous electromagnetic characteristics of the lightning arrester is solved, and the simulation effect of the zinc oxide lightning arrester is improved.

The invention provides an optimum structural design method for a parabolic-arc seal head. The method comprises the following steps: 1, setting characteristic parameters and initial design parameters of the parabolic-arc seal head; 2, establishing a two-dimensional geometric model according to the characteristic parameters and the initial design parameters; 3, determining a corresponding function at a minimal stress of the two-dimensional geometric model as an objective function; 4, setting a variable range of the initial design parameters; 5, performing optimized analysis on the initial designparameters by setting constraints and loads so as to obtain stress intensity values corresponding to the initial design parameters by using finite element analysis software; 6, substituting the stress intensity values into the objective function, judging whether the objective function is convergent and meets constraint conditions, if not, modifying the initial design parameters and returning to the step 5; and 7, obtaining the optimized design parameters when the objective function is convergent and meets the constraint conditions.

The invention discloses a method and a system for calculating a two-dimensional steady-state seepage field of a foundation pit under the support of a suspended retaining wall, a half section of the foundation pit is calculated and analyzed according to symmetry, and the seepage field around the foundation pit is divided into four regular areas by taking the retaining wall direction of the foundation pit as a z axis and the horizontal line direction of the wall bottom as an x axis; establishing a two-dimensional geometric model of the foundation pit in the isotropic single-layer soil layer under the support of the suspension type impermeable retaining wall; assuming that the soil texture of the upper soil layer of the impervious layer is uniform and the seepage of the soil body is isotropic and accords with the Darcy law, solving a simplified expression of a water head of each region by utilizing a separation variable method in combination with boundary conditions of each region of the seepage field of the foundation pit; and constructing a non-homogeneous equation set by utilizing continuous conditions among the regions, solving to obtain a constant term, and substituting the constant term into a simplified expression of a regional water head, so as to obtain a simplified solution of water heads inside and outside the foundation pit. According to the method, the water pressure borne by the retaining wall can be accurately calculated, and the method has remarkable engineering significance for guaranteeing safe construction of a foundation pit.

The invention discloses a method for automatically decomposing two-dimensional regions oriented to the generation of structured quadrilateral grids. Currently, the generation of structured meshes for complex geometric shapes mainly relies on manually decomposing complex regions into regular subregions, which increases the possibility of errors. Steps of the present invention: establish a two-dimensional geometric model for analyzing the entity object, and discretize it into a triangular mesh model; establish a control partial differential equation of the smooth vector field in the inner region of the two-dimensional geometric model according to the geometric boundary constraints, and use the boundary element numerical method to solve the problem ; Establish the smooth frame field corresponding to the smooth vector field, and realize the automatic decomposition of the two-dimensional geometric model by analyzing the singular structure of the smooth frame field. The invention can automatically and quickly obtain the high-quality partition results of arbitrary complex two-dimensional geometric models, and provides input for subsequent generation of multi-block structured quadrilateral grids.

The invention discloses a method for an imaging geometric model based on a Pluecker straight line, and belongs to the field of surveying and mapping. The method comprises the following steps that a homonymous straight line is extracted from image space and object space; the image space is linearly and spirally moved to be linearly coplanar with the object space, and a coplanar condition equation is obtained; a Pluecker straight line imaging geometric model of a strong geometric condition can be built through the coplanar condition equation; an outer orientation element is calculated through the least square adjustment theory. The spiral movement of a space vector can be visually and clearly represented through the Pluecker straight line, the model is simple, and the geometric meaning is clear. Compared with a traditional method, the imaging geometric model based on the Pluecker straight line is higher in geometric locating precision and more stable in result.

The invention provides a national flag detection method based on a single image. The method comprises the following steps: constructing a pentagram geometric model; extracting an edge point of each five-pointed star from the shot image; extracting five vertexes of the five-pointed star from the edge points of the large five-pointed star; calculating object space coordinates of five vertexes of thelarge star, and correcting the posture and distortion of the camera; coordinate transformation is conducted on the vertex of each five-pointed star, and the center and the angle of each five-pointedstar are calculated; and comparing the calculated center and angle of the five-pointed star with the national flag specification to judge whether the national flag meets the specification or not. Theinvention provides a national flag detection method based on a single image. A pentagram geometric model is constructed on the basis of a pentagon geometric model, pentagram extraction is carried outon a single image shot by a common digital camera, the proportion of a real object is restored, and whether the national flag contains pentagrams which do not conform to specifications or not is accurately judged by utilizing the constructed pentagram-shaped two-dimensional geometric model.

The invention discloses a method for extracting finite element node coordinates based on image processing. Under CAD software, grids are manually divided for a two-dimensional geometric model, a picture with the model of the well divided grids is cut out, segment intersection points are determined by processing number and positions of pixel points around each pixel point, relative positions of each node are determined, and real coordinates of the nodes are obtained through coordinate transformation. According to the method, the intersection points can be extracted conveniently, and finite element pre-processing efficiency is greatly improved.

The invention discloses a two-dimensional high-order grid generation method based on partial differential equation solving. At present, generation of high-quality and high-precision high-order grids is still an open problem. The method comprises the following steps: firstly, generating a linear grid covering the two-dimensional geometrical model of the aircraft wing shape, and establishing a mapping relationship between the boundary of the linear grid and the boundary of the two-dimensional geometrical model of the aircraft wing shape; then, ascending the order of the linear grid, establishinga partial differential equation for controlling an internal grid point offset vector field by taking an ascending order linear grid boundary offset vector as a constraint, and solving the partial differential equation by adopting a high-order boundary element numerical method; and finally, shifting all grid points of the ascending order linear grid along respective corresponding shifting vectors,and representing each shifted line unit in a high-order geometrical form to obtain a high-order grid. The method effectively improves the precision and speed of obtaining the offset vector field, andachieves the quick generation of high-quality high-order grid units as few as possible based on the airplane wing shape model.

The invention relates to a thermal barrier coating interface cracking prediction method. The method comprises the following steps: S1, constructing a two-dimensional geometric model of the thermal barrier coating; s2, dividing grids, and inserting cohesion units in TGO / TC and TGO / BC interfaces; s3, setting parameters of the TC layer, the TGO layer, the BC layer and the SUB layer respectively, and adding damage parameters to TGO / TC and TGO / BC interface cohesion units; s4, assembling the two-dimensional geometric model of the thermal barrier coating, and setting the thermal cycle load time of the viscosity analysis step as T; s5, applying a symmetric boundary condition to the left side of the thermal barrier coating two-dimensional geometric model, applying a periodic boundary condition MPC multi-point coupling constraint condition to the right side of the thermal barrier coating two-dimensional geometric model, and constraining the y-direction freedom degree at the bottom; s6, applying a thermal cycle load of the analysis step through a self-defined amplitude curve; and S7, circulating the step S6 to complete a preset number of thermal load cycles to obtain a cracking prediction result of the two-dimensional geometric model of the thermal barrier coating. The method can effectively predict the nucleation position and the expansion condition of the interface crack of the thermal barrier coating.

The invention discloses a finite element calculation method for round billet continuous casting solidification heat transfer, and relates to the technical field of steel continuous casting. The method comprises the steps that a round billet two-dimensional geometric model is established according to the round billet section size; grid division is conducted on the round billet two-dimensional geometric model, and a round billet two-dimensional finite element model is constructed; establishing a round billet two-dimensional finite element solidification heat transfer model aiming at the round billet continuous casting solidification heat transfer problem; and the temperature field change in the continuous casting process is calculated through the round billet two-dimensional finite element solidification heat transfer model. According to the method, the arc-shaped boundary of the round billet is fully considered, a general quadrilateral unit is adopted, when grids are dense enough, any curve of the boundary of a region can be simulated and calculated through segmented straight lines on the boundary, and meanwhile the situation that the boundary is zigzag due to the adoption of a rectangular unit is avoided; compared with a finite difference method, the finite element method is adopted for calculation, so that the calculation precision is improved; proper boundary conditions are selected according to different cooling conditions of the crystallizer and each secondary cooling area, and the heat transfer phenomenon in the actual continuous casting production process of the round billet is simulated more accurately.

The invention relates to an atomized liquid drop coalescence simulation method in a whole shaft, and belongs to the technical field of shaft multiphase flow simulation, and the method comprises the following steps: S1, obtaining atomized acid flow initial parameters in the shaft based on an atomization generator experiment; S2, based on an Euler model and a group balance model, establishing a flow coalescence model of atomized acid in a shaft; S3, dividing the shaft into n sections, wherein the length of each section is b meters, and the width of each section is a meters, establishing a two-dimensional geometric model, encrypting grids near the shaft wall, inputting the initial parameters into the front b-meter shaft for calculation; S4, using a user-defined function to fit and compile the parameters of the outlet end of the first b meters, inputting the parameters into the b-2b well section, and extracting the parameters of the outlet end after calculation is completed; and S5, repeating the step S4 until the whole wellbore is calculated. The simulation of atomized acid flow coalescence in the whole shaft is completed through the steps S1 to S5, and the result is post-processed. The segmented continuous calculation method can simulate the particle size change and distribution state of liquid drops in a shaft of thousands of meters.

The invention discloses a bionic fish hydrodynamic prediction method based on CFD and MLP. The bionic fish hydrodynamic prediction method comprises the following steps: establishing an improved self-propelled motion model; constructing a bionic fish two-dimensional swimming geometric model by using a specific airfoil profile; carrying out grid division on the two-dimensional geometric model by adopting an overlapping grid method, and carrying out grid independence verification; determining input and output parameters, fusing the two-dimensional geometric model and the self-propelled motion model based on UDF, and taking a two-dimensional incompressible unsteady Navier-Stokes equation as a control equation; determining variables, setting boundary conditions, carrying out numerical simulation on the hydrodynamic force of the self-propelled model, and studying the influence of parameters on the motion performance of the bionic fish; according to a numerical simulation result, establishing a hydrodynamic prediction model based on MLP; optimizing parameters through a multi-target genetic algorithm, carrying out hydrodynamic prediction on the optimized parameters through CFD, MLP and RSM methods. The accuracy of an MLP prediction model is verified, and the effects that starting can be fast, and the quasi-steady-state swimming speed and movement efficiency can be improved are achieved.

The invention discloses a wet chemical etching simulation-based flexible PCB etching process online regulation and control method, which comprises the following steps: constructing a flexible PCB equivalent two-dimensional geometric model by utilizing multi-physics field finite element simulation software, establishing a multi-physics field simulation model, finishing setting material attributes, boundary conditions and initial conditions, and performing simulation. By taking process parameter data possibly appearing in various production lines as simulation boundary conditions, various process parameter data possibly permutated and combined as simulation parameter data are input into a simulation system and subjected to simulation calculation, and a database in which the simulation parameter data and simulation results are in one-to-one correspondence is obtained. Then the production line data collected in real time is matched with the simulation parameter data in the database, a corresponding simulation result is called, and if the simulation result exceeds a product index, production is stopped, and process data is regulated and controlled, so that early production line process problems are monitored, and online adjustment of process parameters is completed.

The invention discloses a parameterization design method of a pressure self-tightening sealing structure, which comprises the following steps: firstly, creating a two-dimensional geometric model of the pressure self-tightening sealing structure by using CAD software, and determining a geometric relationship among a valve body 1, a stuffing box 2, a four-opening ring 3, a gasket 4 and a sealing ring 5 in the pressure self-tightening sealing structure; secondly, obtaining geometric parameters of the pressure self-tightening sealing structure, and determining basic parameters and driving parameters of parameterized design; finally, adding basic parameters and driving parameters into an EXCEL software interface, writing a function relation between the basic parameters and the driving parameters, and forming a parameterized design program of the pressure self-tightening sealing structure. According to the invention, rapid design of the pressure self-tightening sealing structure is achieved, the design efficiency is improved, the design accuracy is improved, and the superiority of the method is embodied.

The invention discloses a planar region parameterization construction method based on a frame field. Most of existing parameterization adopts artificial decomposition of sub-regions, and the quality cannot meet the requirements. The method comprises the following steps: firstly, generating a triangular background grid in a two-dimensional geometric CAD model, and calculating a frame and a vector of the two-dimensional geometric CAD model at points on a boundary; secondly, establishing a Laplace equation, and solving the Laplace equation by utilizing discretization of a Laplace-Beltellom operator to obtain vectors and frames of all points in the two-dimensional geometric CAD model; secondly, establishing and simplifying an internal streamline of the two-dimensional geometric CAD model to realize regional decomposition; and finally, constructing a Coons surface for each sub-region in the two-dimensional geometric CAD model, and smoothing all the Coons surfaces to obtain a planar region parameterized structure. According to the invention, errors caused by artificial decomposition of the sub-regions are avoided, and the parameterization generation efficiency is improved.

The invention discloses a method and system for analyzing the pore pressure of soil around a single-layer soil foundation pit under water level fluctuation, and the method comprises the steps: taking a half section of the foundation pit according to symmetry, carrying out the calculation and analysis, and building a two-dimensional geometric model of the foundation pit in a single-layer soil layer supported by a suspension type impermeable retaining wall under the condition of underground water level fluctuation; a foundation pit retaining wall and a wall bottom horizontal line are used as boundary lines, a seepage field around a foundation pit is divided into three regular areas, and control balance equations in the areas are established on the basis of the seepage theory; the established foundation pit two-dimensional geometric model in the single-layer soil layer is combined with foundation pit two-dimensional seepage basic assumption, boundary conditions of all subdomains of a foundation pit seepage field are obtained, and the pore pressure of all the areas is expressed in a series sum mode through a variable separation method; and establishing a matrix equation set by utilizing continuous conditions among the regions, solving to obtain a constant term and a series term in the pore pressure analytical expression, and substituting the constant term and the series term into the pore pressure expression to obtain a pore pressure complete analytical solution of the soil body around the foundation pit. Certain engineering reference is provided for foundation pit design.