20 results about "Mesh free" patented technology

The invention discloses a meshless EFGM-based multi-scale topological optimization method for an anisotropic multi-material periodic steady-state heat transfer structure, and the method comprises the steps: (1) inputting the number of material types, a thermal conductivity factor, the number of design subdomains, a material direction angle and other parameters of an anisotropic structure, and employing EFGM nodes to discretize macro and micro design domains; (2) solving a microcosmic equivalent heat conduction matrix by using a homogenization method; (3) solving a macroscopic equivalent heat conduction matrix by using an SIMP multi-material interpolation method; (4) solving a macroscopic temperature field of the anisotropic structure based on meshless EFGM; (5) establishing a multi-scale topological optimization mathematical model of the multi-material periodic steady-state heat transfer structure based on a meshless EFGM and a homogenization method; (6) solving macro-micro volume sensitivity and thermal flexibility sensitivity, and applying macro periodic constraint; (7) solving the mathematical model, and updating macro and micro EFGM node relative density design variables by using an OC method; according to the method, multi-scale topological optimization of the anisotropic multi-material periodic steady-state heat transfer structure is carried out based on the meshless EFGM, and the structure is clear, smooth, practical and efficient.

The application discloses a non-uniform noise background-based sparse array gridless parameter estimation method, and the implementation steps are as follows: a sparse array structure is arranged at a receiving end; a sparse array receiving signal in a non-uniform noise background is modeled; a covariance matrix of the array receiving signal is calculated; receiving data of a virtual differential common array is calculated through vectorization and de-redundancy; a distribution to which a fitting error is subjected is derived, and a parameter estimation optimization model based on atomic norm minimization and avoiding a complex regularization parameter determination process is constructed; a semi-positive definite programming form of a primal problem and a dual problem is derived; and a wave direction estimation result is obtained through a MUSIC algorithm or polynomial root seeking. In addition, on the basis of fully utilizing a virtual differential common array of the sparse array to provide extended degrees of freedom and all information, the application restrains the influence of non-uniform noise by constraining the sparsity of data atoms to be recovered and selecting a regularization parameter from a chi-square distribution table according to a distribution to which a fitting error between the data to be recovered and actual receiving data not affected by noise is subjected, overcomes the grid mismatch problem caused by parameter domain discretization, avoids a complex process of determining the regularization parameter, and can obtain a higher-precision source direction estimation result.

The invention discloses a meshless Galerkin-Newmark method for calculating a transient wave propagation problem. The meshless Galerkin-Newmark method comprises the following steps: dispersing a transient wave propagation problem domain into nodes; selecting an interpolation primary function and a weight function; constructing a node interpolation primary function and a global interpolation format by adopting a moving least square method based on the selected function; based on a global interpolation format, combining a partial differential control equation and a Galerkin weighted residual value method to obtain a transient wave propagation problem system matrix equation; performing time domain discretization through a Newmark time integration method to obtain a discrete time equation; solving the discrete time equation to obtain a numerical calculation result; and analyzing a result and comparing the result with a common method to finish solving and analyzing a transient wave propagation problem. The meshless Galerkin-Newmark method for calculating the transient wave propagation problem has a monotonous consistent convergence characteristic in the numerical calculation of the transient wave propagation problem, and the calculation precision can be continuously improved along with the reduction of the time integral step length.

The application discloses an enhanced mobile least square meshless-Newmark integral method for reducing total dispersion error of transient wave propagation, and belongs to the technical field of numerical analysis and total dispersion error prediction of transient wave propagation, and comprises the following contents: a wave propagation problem domain is discretized into a series of nodes; a standard mobile least square interpolation base function of each node is derived; a local numerical approximation of an enhanced least square algorithm is completed; a global interpolation format of a general scalar field based on the enhanced least square algorithm is constructed; a system matrix equation of the dispersion analysis of the transient wave propagation problem is obtained by adopting a Galerkin weighted residual method and a Newmark time integral method; and based on a given node distribution, the total dispersion error of different calculation methods along different wave propagation directions under different time integral step lengths is calculated. The application adopts the above method, reduces the total dispersion error caused by the coupling of spatial dispersion and time dispersion, and improves the solving precision.

The invention belongs to the technical field of petroleum geophysical exploration, and relates to an overlapped meshless undulating surface seismic wave field numerical simulation method and system. The method comprises the following steps: establishing an undulating surface seismic wave speed model and an absorption attenuation Q model based on geological parameters of an exploration area; based on the undulating surface seismic wave speed model and the absorption attenuation Q model, adopting an overlapping meshless node subdivision method to obtain a node data set of an overlapping region; taking the node data set as input, expanding a radial basis function based on a Chebyshev polynomial and forming a difference matrix, and solving to obtain a node difference coefficient set; and taking the node data set and the node difference coefficient set as input, performing finite difference discretization on a Kelvin-Voigt model-based viscous-acoustic wave equation based on a radial basis function, implementing forward continuation of the wave field, and completing the seismic wave field numerical simulation of the overlapped meshless undulating surface. According to the method, the constant Q model is accurately described, amplitude-phase decoupling is realized, and the absorption attenuation effect of the medium can be effectively described.

This invention belongs to the field of oil and gas development technology, and relates to a method, system, and readable medium for integrated simulation and crossflow prevention based on the meshless connected element method. The method includes: arranging nodes in the computational domain using an adaptive point placement algorithm based on reservoir geological parameters; constructing a meshless connected element model based on generalized finite difference theory; fitting the meshless connected element model to historical production data from chemical flooding to obtain the pressure potential energy distribution of each node, and constructing a directed pressure potential energy graph for the entire field; starting from the injection well, traversing all potential flow paths connecting injection and production wells in the directed pressure potential energy graph to establish an integrated simulation and crossflow model; classifying the crossflow situation of the flow paths according to the integrated simulation and crossflow model, and generating the optimal prevention scheme based on the classification results. This invention overcomes the problems of mesh orientation effect and low computational efficiency of traditional mesh methods, and achieves visualized prevention of hidden crossflow channels in deep reservoirs.

The application discloses a kind of sparse array amplitude-phase error correction-based meshless parameter estimation method, and its implementation steps are: receiving end is laid out sparse array;The received signal of sparse array with array element gain phase error is modeled;Sample covariance matrix is constructed;The output signal of virtual differential common array is calculated by vectorization;Define the atom norm of introducing amplitude-phase error parameter, and construct the optimization model for target direction estimation;By dual atom norm, the original optimization problem is converted into its dual problem;The semi-positive definite programming form of dual problem is deduced;Dual polynomial is constructed, and the wave direction estimation result is obtained by spectral peak search.In addition, the application fully utilizes the virtual differential common array of sparse array to provide extended degrees of freedom and all information, and suppresses the influence of array element amplitude-phase error by defining new atom norm, solves the mesh mismatch problem caused by parameter domain discretization, and obtains high-precision meshless direction estimation result.

The invention discloses an enhanced meshless Galerkin algorithm for reducing the frequency dispersion error of wave propagation analysis, which comprises the following steps: dispersing a wave propagation problem domain into nodes, selecting an interpolation primary function and a weight function, constructing an approximate interpolation function based on a standard meshless Galerkin algorithm, determining an undetermined coefficient through least square fitting, and determining the frequency dispersion error of the wave propagation analysis. Further establishing a physical field global interpolation format; constructing local reinforcement numerical approximation containing a local reinforcement interpolation primary function and a coefficient at the node; constructing a global interpolation format based on an enhanced meshless Galerkin algorithm on the basis of local enhanced numerical approximation under the condition of meeting unit decomposition characteristics; and an obtained global interpolation format is combined with a wave propagation problem partial differential control equation and a Galerkin weighted residual value method to obtain a system matrix equation which is used for frequency dispersion error analysis of the wave propagation problem. By adopting the enhanced meshless Galerkin algorithm for reducing the frequency dispersion error of wave propagation analysis, the frequency dispersion error can be remarkably reduced, and a more accurate numerical calculation result can be obtained.

The embodiment of the invention provides an oil cooling electric drive system thermal management method and a product. According to the method, oil flow field analysis is conducted on the oil cooling electric drive system through a particle method, convection heat exchange coefficient distribution of an oil flow field is obtained, thermal analysis is conducted on the oil cooling electric drive system according to meshless simulation software and convection heat exchange system distribution, temperature field distribution is obtained, and the oil cooling electric drive system is managed according to the temperature field distribution. The particle method is adopted for oil flow field analysis, the particle method can be used for simulating the characteristics of complex free surfaces, splashing and stirring oil flow in oil cooling and electric drive in a high-precision mode, the obtaining precision of convective heat coefficient distribution is improved, and therefore the accuracy of boundary conditions is guaranteed from the source. The thermal analysis is carried out by adopting meshless simulation software, so that a tedious and time-consuming grid division process with high requirements on experiences of engineers can be avoided, the pretreatment time is greatly shortened, and the management precision and the management efficiency are improved.

The invention discloses a meshless EFGM-based topological optimization method for a multi-material periodic steady-state heat transfer structure. The method comprises the following steps: (1) inputting material attributes such as a heat conductivity factor, a material direction angle, a volume fraction ratio and a heat conductivity coefficient of the multi-material periodic structure; (2) discretizing a design domain by using a meshless method, and carrying out EFGM multi-material steady-state heat transfer analysis; (3) setting iteration parameters and an initial multi-material EFGM node relative density matrix; (4) solving an EFGM discrete control equation after punishment of the SIMP multi-material interpolation model; (5) establishing a topological optimization mathematical model of the multi-material periodic steady-state heat transfer structure based on EFGM; (6) performing periodic averaging processing, and solving volume sensitivity and thermal flexibility sensitivity; (7) optimizing and updating a multi-material EFGM node relative density matrix through two-phase competition; (8) inputting a termination condition, and judging whether loop iteration is continued or not; and (9) outputting a multi-material distribution cloud picture. According to the method, topological optimization of the anisotropic multi-material periodic steady-state heat transfer structure is carried out based on the meshless EFGM, and the structure is clear, simple and practical.

The invention discloses a double-stator motor topological optimization method based on meshless node density optimization and a motor topological structure, and belongs to the technical field of motor design and topological optimization. The method comprises the following steps: firstly, constructing a shape function containing a dynamic influence domain radius, an adaptive weight function and a three-dimensional quartic kernel base difference structure through an MLS; a PINN and PPO dual-module AI architecture is utilized to output node density, a physical field sensitivity coefficient and an adjustment parameter, and accurate correction of the node density is realized through a sensitivity threshold; then, a continuous density field is constructed based on a Shepard function, and collaborative optimization of light weight, high rigidity and strong heat dissipation is achieved in combination with an improved topological objective function and regionalization constraints; and finally verifying the effectiveness of the topological structure through finite element method high-fidelity simulation. The double-stator motor is divided into a high-sensitivity area, a medium-sensitivity area and a low-sensitivity area according to physical field sensitivity, differential constraints are applied, and the contradiction between calculation precision and efficiency under a complex boundary is effectively solved.

The application discloses a three-dimensional meshless numerical simulation method for water dynamic characteristics of a net. The method comprises the following steps: obtaining a net to be numerically simulated; constructing a fluid motion control equation according to a continuity equation and a momentum equation, and performing discrete processing on the fluid motion control equation based on a smoothed particle hydrodynamics method, and combining a wave making function to construct a meshless numerical water tank; performing Lagrange type particle discrete processing on the net according to the shape of the net, and combining a screen model to construct a Lagrange type net particle model; reading the Lagrange type net particle model into the meshless numerical water tank, and performing meshless coupling calculation on the net and the fluid in each time step to obtain fluid resistance received by the net. The application realizes numerical simulation of water dynamic characteristics of the net under complex marine environment by adopting the smoothed particle hydrodynamics method to disperse the fluid control equation, and can be widely applied to the field of marine engineering technology.

The invention provides a partial differential equation rapid solving method and solver based on a grade radial basis function, and relates to the technical field of computers and numerical calculation, and the method comprises the steps: obtaining a to-be-solved partial differential equation and a calculation region; the calculation area is jointly defined by a central point set, a configuration point set and an evaluation point set; applying a nested relationship constraint to the central point set to construct a nested sequence, so that a low-level point set covers a global domain, and a high-level point set realizes coarse-scale global representation and fine-scale local focusing through local encryption; assembling a radial basis function with a self-adaptive support radius for each scale level on the basis of applying a nested relationship constraint to the central point set to obtain a variable support set kernel function; establishing a grade radial basis function test space by adopting a grade construction method; and based on the level radial basis function heuristic space, solving the to-be-solved partial differential equation through a level radial basis function assembly point method. According to the scheme, the partial differential equation can be rapidly solved in a meshless mode.

The application discloses a three-dimensional integrated microsystem electric-thermal cooperative calculation method based on a meshless Galerkin method, and comprises the following steps: establishing a background integral grid based on a three-dimensional integrated microsystem model, and establishing integral points by using grid and boundary information; finding integral points in a solution domain, and determining field nodes of a support domain where the integral points are located; calculating a shape function and a derivative thereof at each integral point; obtaining a temperature stiffness matrix and a node thermal load matrix at a boundary, and a basic temperature stiffness matrix and a basic node thermal load matrix based on the shape function and the derivative thereof; adding electric-thermal coupling terms in the basic temperature stiffness matrix and the basic node thermal load matrix to obtain a temperature stiffness matrix and a node thermal load matrix in a discrete domain; and obtaining a temperature field of the three-dimensional integrated microsystem model according to the temperature stiffness matrix and the node thermal load matrix at the boundary, and the temperature stiffness matrix and the node thermal load matrix in the discrete domain. The application eliminates the influence of grid shape on a solution result, and ensures precision.

An improved SBFEM method based on a consistent one-point integral theory belongs to the field of computational mechanics, and comprises the following steps: firstly, carrying out weighted average on a compatible strain field in a unit domain by adopting a linear strain smoothing technology to obtain a smooth strain field; secondly, representing a linear smooth function in a nodal function derivative form, and establishing a correction equation based on a discrete form of a divergence theorem; thirdly, adopting one-point integration at the geometric center of a sub-triangular domain, introducing a high-order derivative, and correcting the nodal function; fourthly, the corrected first-order partial derivative and the corrected second-order partial derivative of the shape function are substituted into a divergence theorem equation, and a corrected shape function derivative is solved; and finally, substituting the derivative of the nodal function into the stiffness matrix, determining a corrected stiffness matrix of the unit, and expanding the corrected stiffness matrix in a Taylor expansion form to obtain an efficient and stable corrected stiffness matrix. According to the method, the advantages of the consistent integral thought in the meshless method and the boundary discrete characteristic of the SBFEM are synergistically exerted, and elastic and elastic-plastic analysis is supported.

The invention provides an enhanced meshless Galerkin numerical method for calculating a steady-state wave propagation problem, and belongs to the field of numerical simulation calculation and numerical forecasting of the steady-state wave propagation problem, and the method comprises the steps: dispersing a steady-state wave propagation problem computational domain into a node set, constructing a physical field variable initial interpolation format based on a meshless Galerkin method, and carrying out the numerical simulation calculation of the steady-state wave propagation problem. Deriving a node interpolation function; selecting a combination of a first-order Lagrange polynomial and a trigonometric function as a local strengthening primary function, and introducing a new node degree of freedom to construct a local strengthening interpolation; the unit decomposition characteristics are maintained, a global interpolation format is constructed, a numerical model is established in combination with a partial differential equation and a Galerkin method, and a physical field variable of any point is solved after conditions are applied. According to the enhanced meshless Galerkin numerical value method for calculating the steady-state wave propagation problem, the problem of insufficient precision of a traditional meshless Galerkin numerical value method in wave propagation problem numerical calculation is solved.

The present application relates to electronic communication signal positioning identification technical field, especially to a kind of hybrid field source signal positioning method and system based on meshless, for the target area in hybrid field source, construct four-order cumulant matrix that has eliminated distance parameter: generate four-order cumulant matrix equivalent to uniform array by interpolation operation on four-order cumulant matrix;Based on four-order cumulant matrix equivalent to uniform array and using atomic norm theory to construct hybrid field source direction of arrival estimation optimization problem;Hybrid field source direction of arrival estimation optimization problem is solved using the MUSIC matrix characteristic space decomposition method, and direction of arrival estimation value and distance estimation value of hybrid field source are obtained according to solving structure.The present application can realize high-precision hybrid field positioning, and positioning success rate is high, with good robustness, with good application prospect.

The invention discloses an earth and rockfill dam heaping scheme optimization method and system based on deformation inclination and dam slope stability dual control, and belongs to the technical field of earth and rockfill dam construction. A three-dimensional entity model is established by obtaining dam body partition, geology and water level conditions; performing grid discretization according to the minimum construction layering size, and densifying a core wall and a dam slope or a weak interlayer area; setting candidate schemes of different vertical layering heights and filling sequences of the core wall and the rockfill or the main rockfill and the secondary rockfill, and obtaining a displacement field and a stress field by adopting finite element or meshless analysis; calculating the deformation inclination of the dam in the axial direction and the river-following direction, and performing dam slope stability analysis to determine a safety coefficient; and a settlement extreme value, a deformation inclination extreme value and a safety coefficient are extracted, schemes are screened according to constraints that the settlement is not higher than 1% of the dam height, the deformation inclination is not higher than a preset limit value, and the safety coefficient of a dam slope is not lower than 1.3, and a stacking scheme with the highest construction efficiency is preferably selected from the schemes meeting safety. According to the method, the anti-seepage structure deformation risk and dam slope stability can be considered, and the construction efficiency is improved.

The invention relates to a meshless impact collision simulation method based on point-to-surface contact. The meshless impact collision simulation method comprises the following steps: (1) initializing meshless nodes and material points by utilizing a finite element grid; (2) determining master and slave contact nodes, reconstructing the nodes of the master contact surface, and obtaining an external normal vector of each node of the master contact surface; (3) establishing a contact pair and setting contact parameters; (4) judging whether the slave contact node enters a contact effective area or not, and obtaining a corresponding node contact acting force; (5) assembling node contact acting force, and obtaining physical information and dynamic data of the material points and the nodes in a time period from t0 to tn; and outputting a simulation result. According to the method, the main contact surface can be stably constructed without structural topology, the external normal direction is accurately obtained, the contact force is distributed, the numerical stability and the explicit time integral compatibility are kept, and the method is suitable for contact behavior simulation under the working conditions of large deformation of processing materials, impact collision, multi-body collision and the like.

The invention relates to a high-speed body impact simulation method based on a meshless smoothed particle Galerkin algorithm. The high-speed body impact simulation method comprises the following steps: establishing a geometric model of a high-speed body and a target plate body; setting a target plate body as a flexible body, and performing particle dispersion on an area within N times of the diameter of a high-speed body from an impact point by adopting SPG to form a high-strain area; a finite element method is adopted to divide grids in areas outside N times of the diameter of a high-speed body starting from the impact point to form low-strain areas; the SPG particles are connected with the finite element mesh through a common node constraint; setting a high-speed body as a flexible body, and carrying out particle dispersion by adopting SPG; a flexible body-flexible body SPG particle contact model is adopted between the high-speed body and the target plate body; sPG particles are adopted in the high-strain area, and a point-surface contact mode with a finite element mesh as a surface is adopted; and calculating the aerosol generation rate in the impact process according to the total mass of the highway and the kinetic energy change curve. And the whole process behavior of flexible body impact deformation-material fracture crushing-aerosol conversion in high-speed impact is accurately described.