26 results about "Isogeometric analysis" patented technology

The invention belongs to the field of material structure optimization, and particularly relates to an isogeometric topological optimization method based on dynamic response driving, which comprises the following steps of: (1) establishing a thin shell mid-plane geometric representation model based on a T spline and Bessel extraction technology; (2) establishing a frequency response-oriented isogeometric shell unit based on the Kirchhoff theory; (3) solving the aerodynamic response of the surface of the structure based on a high-order panel method of a T spline; (4) constructing a topology description model of the thin shell based on a Bessel unit; (5) establishing a structure dynamic flexibility minimum topological optimization model oriented to the dynamic response of the pneumatic thin shell; (6) dynamic flexibility minimization sensitivity analysis and derivation; and (7) updating optimization model design variables based on an optimal criterion method. According to the method provided by the invention, a pneumatic coupling thin shell dynamic isogeometric analysis framework is constructed, and the problems of poor geometric adaptability, difficulty in complex thin shell dynamic design, lack of pneumatic environment related to optimization and the like in an existing method are effectively solved.

The application discloses a structure nonlinear deformation reconstruction method and system based on isogeometric and reduced basis, and the method comprises the following steps: measuring initial strain data of a ship plate structure surface, constructing a plurality of four-node inverse shell elements of the ship plate based on the initial strain data; assembling the plurality of four-node inverse shell elements to obtain a whole stiffness matrix; reconstructing the whole stiffness matrix based on the measured strain data of the ship plate to obtain a linear reconstruction result of the ship plate; correcting the linear reconstruction result based on the reduced basis, and fusing the correction increment to the linear reconstruction result for nonlinear iteration to complete nonlinear deformation reconstruction. On the basis of the principle of isogeometric analysis, the application combines the inverse finite element method to establish a four-node inverse shell element, realizes high-precision ship structure displacement reconstruction through a small number of strain measuring points, and helps designers to intuitively understand and deeply understand the mechanical properties of the structure and to monitor the safety of the structure in real time.

The invention belongs to the technical field related to robot machining, and discloses an optimal design method and equipment for a three-dimensional complete continuous functional gradient lattice extension rod, and the method comprises the steps: constructing a mapping relation between geometric and physical properties of a lattice structure; by combining the continuous, smooth and locally controllable characteristics of the NURBS body, the completely continuous characterization and regulation of the property distribution of the functionally gradient lattice structure are carried out, the completely continuous smooth transition of the lattice structure in a three-dimensional space is realized, and compared with an incomplete continuous functionally gradient lattice structure, the preparation method has the advantages that the preparation cost is reduced; the completely continuous functional gradient lattice structure has higher structural strength and optimization potential; a high-order shear beam theory and an isogeometric analysis method are combined to construct a dynamic model of a three-dimensional complete continuous functional gradient lattice structure, and a theoretical basis is provided for subsequent robot system dynamic modeling of an additional lattice extension rod; on the basis of the method, distribution characterization-regulation and control design-performance analysis of the three-dimensional completely continuous functional gradient lattice structure can be realized.

The invention is suitable for the technical field of heat conduction analysis, and relates to an underground granary heat insulation performance simulation method based on axisymmetric geometric analysis, which utilizes a non-uniform rational B-spline (NURBS) primary function to accurately represent a geometric shape and approximate a physical field, realizes the unification of modeling and analysis data, and improves the heat insulation performance of an underground granary. The axisymmetric characteristics and boundary conditions of the granary are fully utilized, geometric analysis system equations and solving formats such as the axisymmetric heat conduction problem are deduced in a cylindrical coordinate system from an axisymmetric steady-state heat conduction problem control equation on the basis of the variational principle, and a general three-dimensional problem is reduced into a two-dimensional problem; efficient utilization of the degree of freedom of calculation is achieved, then temperature field and heat flux density distribution characteristics of a granary body-soil body system are analyzed, the influence rule of different conditions on underground granary heat conduction is revealed through parameterization research, and a high-order continuous interpolation basis function is introduced to obtain a high-order continuous interpolation basis function; the calculation precision and calculation efficiency of underground granary temperature field analysis are effectively improved.

The invention discloses a method for generating a quadrilateral curved surface grid, the quadrilateral curved surface grid can cover the curved surface of a three-dimensional object so as to analyze the three-dimensional object, and the method comprises the following steps: obtaining a curved surface digital geometric model of the three-dimensional object; constraint on grid singular point configuration on the curved surface is received, the singular point configuration comprises at least one designated position and a target price number of the designated position, and the price number represents the number of edges connected with grid vertexes; on the basis of the Riemannian-Rooch theory, a finite-dimensional quadrilateral grid generation space is constructed within the range meeting singular point configuration constraints, and construction comprises calculation of a primary function of a sub-pure function linear space L (D) corresponding to singular point configuration; selecting a specific grid generation parameter combination from the quadrilateral grid generation space; a quadrilateral curved surface grid is generated and output according to the grid generation parameter combination, and singular point distribution of the grid conforms to the received constraint; and the quadrilateral curved surface grid is provided for a finite element analysis or isogeometric analysis solver and is used for carrying out simulation analysis of mechanics, thermotics or fluid dynamics on a three-dimensional object.

The invention provides an isogeometric analysis control grid-oriented graph neural network Poisson equation solving method. The method comprises the following steps of S1, matching data set acquisition and input formats; s2, carrying out proportion division on the data set; s3, constructing a graph neural network model; s4, performing model training and parameter initialization; training a model by using a training set, and monitoring a training effect through a verification set by taking Poisson solution error minimization and operation speed maximization as targets; step S5, Poisson solution and performance verification: executing Poisson solution by using the test set, calculating a solution error and a running speed which need to be superior to a file specified standard, and returning to adjust model parameters and retraining if the standard is not reached; and S6, outputting a result. Step S7, Main file integration and interface implementation: writing Main file integration functions from the step S1 to the step S7; according to the method, the problem that the compatibility of a data set and input of an existing method is limited remarkably in the engineering simulation and scientific calculation process can be solved.

This invention discloses a structural thermo-mechanical coupling method and apparatus considering isogeometric analysis, belonging to the field of thermodynamics. The method includes: S1. Establishing an isogeometric NURBS model: providing the basis for expressing geometric and physical fields for thermo-mechanical coupling analysis, achieving seamless integration of CAD and CAE; S2. Calculating the transient temperature field based on the central difference method: obtaining the temperature distribution of the structure at different times, providing temperature input for subsequent thermo-mechanical coupling; S3. Transforming the temperature field into equivalent temperature loads: converting the thermal effects caused by temperature changes into equivalent loads identifiable by structural mechanics analysis; S4. Solving the stiffness equation of the structure under the combined action of external forces and temperature: obtaining the displacement matrix of the structural control points; S5. Solving the structural coupling field based on the displacement matrix: obtaining all key physical quantities in the thermo-mechanical coupling field, completing the coupling analysis. This invention can verify the feasibility of applying isogeometric analysis in coupled fields.

The application relates to the field of artificial intelligence, and particularly discloses an industrial design parameterized design system with multidimensional simulation feedback, which comprises a parameterized modeling module, a multidimensional simulation module, a simulation agent model construction module, a multidimensional feedback fusion and optimization module, an iterative convergence discrimination module and an interactive visual feedback module; the parameterized modeling module is used for generating an integrated parameterized three-dimensional model containing geometric features, material distribution and topological structure according to input design parameters. The application constructs an integrated parameterized three-dimensional model fusing geometric features, material distribution and topological structure, realizes millisecond-level real-time updating of the model through an incremental constraint solver, adopts an isogeometric analysis method based on NURBS, unifies the discretization process of modeling and simulation, avoids model conversion errors and realizes seamless connection of parameterized modeling and multi-physical field simulation.

The embodiment of the application provides a kind of entity unit isogonic analysis method, device, equipment and storage medium for variable-thickness composite material, the method comprises: based on entity geometry model, construct the entity grid model of NURBS, and extract the parameterization information of NURBS;Local coordinate system is established in each gauss point inside geometry entity using parameterization information, determine the first conversion relationship of local coordinate system and global physical coordinate system;Based on entity grid model, construct nonlinear function in parameter space, use L-M algorithm to iteratively solve the intersection of each ply offset surface and thickness direction parameter curve of variable-thickness composite material, determine the integral interval inside each entity unit;Based on geometric volume integral term and the ply trigonometric function of variable-thickness composite material, determine global stiffness matrix;Based on global stiffness matrix, execute isogeometric analysis to determine the laminated structure strain energy, vibration frequency and buckling factor of composite material by loading and defining boundary conditions.

The invention relates to a multi-piece multi-dimensional functionally graded material optimization method, device, equipment and medium, and belongs to the technical field of functionally graded materials.According to the multi-piece multi-dimensional functionally graded material optimization method, a multi-piece three-dimensional functionally graded material porous structure is constructed based on a B spline or NURBS; the constructed PHT-AIGA is adopted to carry out self-adaptive solution and iterative refinement on the geometric configuration of the porous structure of the multiple pieces of three-dimensional functionally graded materials, a numerical analysis template grid meeting an error threshold value is obtained, and the PHT-AIGA comprises geometric analysis such as a PHT spline base, a super-convergence recovery base error estimation algorithm and a Doffler marking strategy; according to the method, a multi-objective optimization function is constructed with the minimum mass and the maximum free vibration fundamental frequency as optimization objectives, iterative solution is conducted on the multi-objective optimization function, optimized design variables are obtained, and the precision and efficiency of multi-objective optimization of the multiple pieces of three-dimensional functionally graded materials are improved.

This application discloses an isogeometric transient temperature field analysis method integrating birth and death element technology, relating to the field of computational mechanics. The method includes establishing an isogeometric NURBS model, calculating the element heat transfer matrix, element thermal melting matrix, and element load array; determining whether the current calculation element is in the computation time domain; if not, setting the element heat transfer matrix and element load array to 0; if so, restoring the loads corresponding to the element heat transfer matrix and element load array, and removing the loads shared by the element and other elements in the computation time domain at their boundary; assembling the element heat transfer matrix, element thermal melting matrix, and element load array into a global matrix, and constructing the heat transfer equation based on the global matrix; calculating the temperature of the control points based on the heat transfer equation, and determining the temperature field of the final solution domain. This application considers the realization of an isogeometric transient temperature field analysis method under complex temperature load conditions including time-series problems, promoting the application of isogeometric analysis in engineering.

The invention discloses a multi-patch structure adaptive isogeometric topology optimization method and system based on a truncation level B spline, and relates to the technical field of CAD / CAE integrated design. According to the method, multi-patch model data is analyzed, and a truncation level B spline space and a multi-patch level isogeometric analysis grid are initialized; constructing a self-adaptive multi-patch isogeometric analysis grid based on a residual posterior error estimator to solve a structural displacement field; meanwhile, a uniform and fine multi-patch isogeometric design grid is constructed, a multi-patch tensor integral solution implicit filter and control point index transformation are utilized to achieve efficient obtaining of sensitivity of an objective function and a volume constraint function on multi-patch control point variables, and an OC optimization criterion is adopted to iteratively update control point optimization variables; in the iteration process, a density change indicator and a posterior error indicator are combined for self-adaptive subdivision and reinitialization, and efficient and high-precision optimization solution under the decoupling condition of the analysis grid and the design grid is achieved.

The application discloses an equal geometry-based multi-scale topological optimization method for anisotropic periodic structure material, and comprises the following steps: (1) modeling according to an equal geometry analysis method to obtain discrete point information of a macro periodic structure and various microstructure design domains, and dividing a design subdomain for the macro periodic structure design domain; (2) constructing a coordinate conversion relationship between a natural coordinate system and a material coordinate system in an anisotropic material; (3) performing periodic material distribution optimization to determine the position of various microstructures in the macro periodic structure and the volume fraction of various microstructures by normalizing the relative density; and (4) performing periodic structure / material multi-scale parallel topological optimization to determine the macro periodic structure, various microstructures and equivalent elastic matrices thereof. The application performs multi-scale topological optimization for an anisotropic periodic structure / material based on equal geometry analysis, and is accurate, stable and efficient in convergence, and can improve the structure performance from the macro and micro scales and the structure and material angles.

The application belongs to the technical field of isogeometric analysis, and discloses an isogeometric stiffness matrix CPU / GPU heterogeneous parallel computing method.The method comprises the following steps: S1, obtaining an isogeometric body grid model of an object to be processed, dividing the isogeometric body grid model to obtain a plurality of body units, control points and Gauss points, and numbering the body units, control points and Gauss points respectively; S2, obtaining corresponding information vector groups of all interactive control point pairs in all body units; S3, obtaining a shape function partial derivative matrix at each Gauss point; S4, calculating a global stiffness matrix of the interactive control point pairs, thereby obtaining global stiffness matrices of all interactive control point pairs, and assembling the global stiffness matrices of all interactive control point pairs, so as to realize heterogeneous parallel assembly of the stiffness matrix.Through the application, the problems of low calculation efficiency, large memory consumption and incapability of isogeometric analysis on large-scale high-resolution models in the existing isogeometric analysis method are solved.

The application belongs to the field of structure optimization design, and discloses a product structure intelligent integrated design method based on neural network reparameterization, constructs a feedforward neural network fusing multi-scale Fourier features, reparameterizes Gaussian point density into weights and biases related to the neural network, takes product structure flexibility as an optimization target, takes neural network model parameters as design variables, and establishes an intelligent integrated design model; solves structure displacement and element flexibility through isogeometric analysis, processes constraints by using the augmented Lagrange method, calculates neural network loss based on linear weighting of the objective function under each volume fraction, dynamically balances weight coefficients based on learning speed and loss value, and realizes solving of the optimization model through an embedded optimizer; calculates a global density function under an expected volume fraction by using trained network parameters, so that an optimal product structure is obtained. The application can efficiently and intelligently obtain a product structure meeting design requirements.

The application discloses a product structure isoparametric topology optimization method and system based on a neural network, and belongs to the field of structure optimization. First, a product structure isoparametric topology optimization model is constructed. An isoparametric topology optimization algorithm is adopted, the spatial coordinates and relative density of fine-grid control points and the displacement and sensitivity of coarse-grid control points are taken as inputs, the sensitivity of fine-grid control points is taken as output, and a training data set is generated. Subsequently, a graph convolutional neural network model with multi-resolution information extraction capability is trained by using the data set. The model comprises a graph convolution module for extracting global stiffness information and a full-connection module for local information fusion. Finally, the trained neural network model is integrated into an isoparametric topology optimization solving process, the sensitivity of fine-grid control points is directly predicted by the neural network, thereby avoiding isoparametric analysis with high calculation cost at the fine-grid level, and the calculation efficiency of product structure isoparametric topology optimization is significantly improved.

The invention discloses a B-spline finite element analysis topological optimization method based on a neural network, which fuses a non-uniform rational B-spline (NURBS) and a physical information neural network (PINNs), and comprises the following steps of: performing geometric region and structural density representation by using the NURBS, inputting a control point of a geometric region into an isogeometric neural network based on the PINN, and outputting a density control point; then, isogeometric analysis is used for displacement calculation, and a structural performance index is calculated as loss. And finally, performing sensitivity analysis by using a built-in back propagation mechanism so as to optimize density field distribution. The optimized density field is obtained through continuous forward propagation, performance index (such as flexibility) calculation, back propagation and weight updating until a preset convergence condition or the maximum number of iterations is reached. According to the method, the modeling capability of the neural network and the accuracy of finite element analysis based on the B-spline can be effectively combined, and efficient and accurate topological optimization is realized.

The invention discloses a full-scale functional gradient porous hierarchical structure transient dynamics topological optimization method and system, and belongs to the field of topological optimization design of functional gradient structures. The problem to be solved is how to construct a transient isogeometric analysis method compatible with a traditional finite element method and integrate the transient isogeometric analysis method into a full-scale functional gradient porous hierarchical structure topological optimization problem, and the engineering expandability of an optimization algorithm is improved. According to the method, a self-adaptive growth strategy of projection parameters is constructed, and continuous regulation and control of structure topology in the optimization process are realized. According to the technical key points, a structure isogeometric transient dynamics finite element model is constructed; constructing a functional gradient porous hierarchical constraint and a material interpolation model based on a sharpness parameter adaptive increase strategy, and proposing a transient dynamic topological optimization model of a full-scale functional gradient porous hierarchical structure; constructing a time domain adjoint equation of the topological optimization model; and the optimal anti-vibration design of the functional gradient porous hierarchical structure is obtained. The designed porous structure has good structural performance and functional characteristics, and can meet the requirements of complex engineering environments in the fields of aerospace, deep sea and the like.

The invention belongs to the field of composite material simulation, and provides a method for calculating the anisotropic stress of a composite material laminated plate based on isogeometric analysis, which comprises the following steps of: establishing a mapping relation between a physical model and a spline surface based on the size of the composite material laminated plate, establishing a displacement strain relation of the composite material laminated plate through a high-order shear deformation function, and calculating the stress of the composite material laminated plate. The stress-strain relation of the composite laminated plate is established through a constitutive equation, the displacement of control points on the composite laminated plate is solved and obtained by applying boundary conditions and adopting an isogeometric analysis method, a virtual work principle and a discrete equilibrium equation, and the stress-strain relation, the constitutive equation and a high-order shear deformation function are used for calculating the displacement of the control points on the composite laminated plate. Stress distribution of the composite material laminated plate in the plate thickness direction is obtained, and stress calculation of the composite material laminated plate is completed. According to the method, the solving efficiency is high, the obtained stress value is accurate, the simulation calculation amount is small, and the method has important significance for evaluating the structural strength of the composite material.

This invention discloses a method for establishing a geometric analysis model for NURBS surfaces using adaptive Loop subdivision, comprising the following steps: (1) setting curvature threshold parameters and a maximum number of samplings; (2) performing initial uniform sampling on the NURBS parameter domain; (3) calculating the curvature threshold and the average curvature of the point set based on the average curvature of the surface, identifying feature regions, and performing Delaunay triangulation on the current point set; (4) marking parameter points based on the curvature threshold, and inserting the marked parameter points into new parameter points based on the Delaunay triangulation relationship, with the new parameter points included in the point set; (5) repeating steps (3)-(4) until the maximum number of samplings is set, thereby capturing geometric details; (6) constructing a Delaunay triangulation on the latest point set; (7) applying Loop subdivision rules to generate a surface representation suitable for isogeometric analysis. The method of this invention is applicable to arbitrary topological structures, requires no multi-patch splicing, and provides a new solution for the accurate mechanical analysis of complex plate and shell structures.

The invention belongs to the field of structure optimization design, and discloses a product structure intelligent integrated design method based on neural network re-parameterization, and the method comprises the steps: constructing a feedforward neural network fusing multi-scale Fourier features, and carrying out the re-parameterization of the Gaussian point density into the weight and bias related to the neural network; taking the product structure flexibility as an optimization target, taking neural network model parameters as design variables, and establishing an intelligent integrated design model; solving structure displacement and unit flexibility through isogeometric analysis, processing constraints by adopting an augmented Lagrangian method, calculating loss of a neural network based on linear weighting of a target function under each volume fraction, and solving an optimization model through a built-in optimizer based on a learning speed and a loss numerical value dynamic balance weight coefficient; and calculating a global density function under an expected volume fraction by adopting the trained network parameters so as to obtain an optimal product structure. According to the invention, the product structure meeting the design requirements can be efficiently and intelligently obtained.

The invention discloses a product structure isogeometric topology optimization method and system based on a neural network, and belongs to the field of structure optimizing.The method comprises the steps that firstly, a product structure isogeometric topology optimization model is constructed; an isogeometric topology optimization algorithm is adopted, the space coordinates and the relative density of the fine grid control points and the displacement and the sensitivity of the coarse grid control points serve as input, the sensitivity of the fine grid control points serves as output, and a training data set is generated; then, the data set is utilized to train a graph convolution neural network model with multi-resolution information extraction capability, and the model comprises a graph convolution module for extracting global rigidity information and a full connection module for local information fusion; and finally, integrating the trained neural network model into an isogeometric topology optimization solution process, and directly predicting the sensitivity of a fine grid control point through the neural network, thereby avoiding isogeometric analysis with high calculation cost on a fine grid level, and remarkably improving the calculation efficiency of isogeometric topology optimization of a product structure.

In order to solve the problems of increasing production time and cost caused by the method of stopping to detect the machining deformation error, and the machining deformation error cannot be found in time, and the accuracy of the machining deformation error obtained by offline prediction is low, the application provides a kind of milling machining deformation error online prediction method. First of all, the CAGD model of the workpiece and the tool is dispersed based on the method of isogeometric analysis, and the stiffness matrix of the discrete unit is solved according to the material constitutive relation, and then the global stiffness field of the discrete model of the workpiece and the tool is established. Then the cutting force signal is collected in real time during the milling process, and the cutting force signal is mapped to the spatial domain through the interaction with the machine tool, and the actual cutting force distribution related to the position in the milling process is obtained. Finally, the actual cutting force at each position is applied to the global stiffness field of the tool and the workpiece respectively, and the deformation prediction value of the tool and the workpiece is obtained, and the machining deformation error prediction result is obtained by adding.

The present application relates to a kind of humanoid robot flexible interaction metamaterial topology optimization system and method, specifically relates to the field of humanoid robot, the weight of the leg structure of humanoid robot is significantly reduced by the topology optimization of mechanical metamaterial, while enhancing its energy absorption and impact resistance, using isogeometric analysis and customized microstructure design, provide lightweight filling structure with negative poisson ratio characteristics for foot and ankle, significantly improve flexibility under the premise of guaranteeing structural strength, this method effectively solves the contradiction between the strength deficiency of traditional flexible material and the excessive weight of rigid element, makes humanoid robot show more safe buffer characteristics and more stable dynamic control performance when interacting with environment, significantly improves the overall interaction safety and complex environment adaptability of robot.

The invention discloses an AI-driven rapid CAD-CAE (computer aided design-computer aided engineering) industrial design simulation software system, and relates to the technical field of computer aided design modeling and computer aided engineering simulation of industrial equipment. A natural language or sketch intention of a user is intelligently converted into an assembly scheme composed of standard parts and parameterized parts, and CAD software is driven to automatically complete modeling. After modeling, an isogeometric analysis framework is adopted, physical field analysis is directly carried out based on NURBS geometry of CAD, and geometric errors of traditional grid division are avoided. A non-matched assembly interface is processed by using a Mortar method and an extended thermal-mechanical coupling model, locking of a thin-wall structure is eliminated by combining a generalized local B-bar method, and parameter-free stable coupling is realized by using an oblique symmetry Nitsche method. Finally, a design-simulation-optimization efficient closed loop is formed, and the automation degree and precision of industrial design simulation are improved.

This invention belongs to the field of road traffic noise reduction technology, and relates to a sound barrier shape optimization method based on the singular boundary method of isogeometric geometry. This method combines isogeometric analysis with the singular boundary method to optimize the sound barrier shape more simply and accurately, improving optimization efficiency. Specifically, it includes the following steps: establishing a geometric model of the sound barrier based on its geometric parameters; extracting information from the established geometric model and importing it into the program to obtain the interpolation points of the geometric model boundary, which are then used as the boundary points of the singular boundary method; establishing a sound barrier shape optimization model using known acoustic control equations; calculating the set objective function and constraints using the optimization model, and iterating the results using the moving asymptote method to obtain the optimal value; and outputting the final optimized shape of the sound barrier. This method avoids repetitive modeling processes during optimization, eliminates the need for mesh generation and numerical integration, and boasts high overall speed, high efficiency, and reliable principles.