20 results about "Spectral element method" patented technology

The invention provides a frequency dispersion curve calculation method based on a decoupling type Legendre-Gauss-Labatto spectral element method, and belongs to the technical field of discrete solution of guided wave propagation in a thin plate, and the method comprises the following steps: S1, constructing a wave equation which comprises a Cartesian space coordinate system based on an orthotropic plate, and combining a constitutive equation, a geometrical relationship under the coordinate system and guided wave displacement to obtain a wave dispersion curve; substituting into a control equation when the volume force is zero to obtain an improved three-dimensional elastic wave equation; s2, a differential matrix is constructed, wherein discretization and decoupling are carried out on a wave equation on the basis of a Lagrange interpolation basis function of a Legendre-Gauss-Labatto node; s3, explicitly embedding the stress free boundary condition into the solving process through matrix line transformation, and solving to obtain a frequency dispersion curve, the derivation process is simplified, the boundary and the interior of the material are decoupled, and the physical significance is clearer. And meanwhile, the high-precision advantage of the spectrum method is maintained, and the calculation rate is remarkably improved.

The invention discloses a seismic simulation method and system fusing an implicit iterative graph network and a spectral element method. The method comprises the following steps: acquiring acceleration data of a small time step node; performing grid sparse division and interpolation mapping processing, and projecting to a low-dimensional manifold to obtain large-time-step node acceleration data and a low-order unit calculation force matrix of the current frame; obtaining a physical relation sparse matrix I, a physical relation sparse matrix II and sparse matrix topological relation information of the physical relation sparse matrix I and the physical relation sparse matrix II through a processing method of Jacobian iteration and projection to a low-dimensional manifold; obtaining a seismic simulated diagram neural network model; and predicting by using the seismic simulation diagram neural network model, and predicting the acceleration by using the large time step of the sparse unit nodes projected back to the target area by using the projection matrix. According to the method provided by the invention, the mapping between the high-order unit small time step and the low-order unit large time step is established through the fitting capability of the neural network, so that the calculation time is greatly shortened, and the earthquake simulation is quickly carried out.

The invention discloses a cross-scale broadband seismic wave field simulation method, and the method comprises the following steps: firstly, carrying out the spatial discretization of a research region based on a spectral element method, generating a three-dimensional cross-scale wave velocity structure grid model, constructing GLL integral points in the grid units of the grid model, and integrating a global seismic wave equation based on the integral points; then, converting a seismic wave equation to be solved into a second-order linear ordinary differential equation on a time domain; performing time domain discretization on the second-order linear ordinary differential equation set by adopting a fourth-order symplectic time integral algorithm; local time step form construction is carried out on the fourth-order symplectic time integral algorithm; and finally, in a discrete grid system formed by the grid model, performing multi-step iterative calculation on the physical quantity of the seismic wave field to obtain a three-component seismic oscillation numerical simulation result of the research area. The method improves the calculation efficiency and the precision of a calculation result.

The invention discloses an SEM-FEM-SPH simulation method and an SEM-FEM-SPH simulation system for a three-dimensional seismic source-landslide. According to the method, a spectral element method, a finite element method and a smoothed particle fluid dynamics method are combined, and simulation of the whole process from seismic source fracture to landslide starting, slippage and accumulation triggered by space seismic oscillation is achieved. The method comprises the following steps: simulating a regional seismic wave field through a spectral element method to generate a local slope spatial non-uniform seismic motion field, proposing a local slope FEM-SPH three-dimensional bridge domain coupling model considering a complex terrain effect, and realizing seamless connection of a regional scale SEM model and the local FEM-SPH coupling model based on an internal input method. According to the method, the limitation of uniformly inputting assumed and preset slip crack surfaces in traditional earthquake landslide simulation is overcome, direct numerical simulation of the whole process from seismic source fracture to earthquake triggered landslide inoculation, migration and accumulation under the high mountain and valley complex site condition can be realized, and a key technical support is provided for earthquake landslide disaster risk assessment.

The invention discloses a broadband seismic oscillation simulation method and system based on probabilistic seismic risk analysis, and relates to the technical field of field seismic oscillation, and the method comprises the steps: carrying out the seismic risk decoupling through employing a Chinese probabilistic seismic risk analysis method, determining a target potential source area corresponding to the maximum contribution degree with probability significance and a potential source magnitude and an epicentral distance of the target potential source area; calculating a fault size parameter of the target potential source area based on the potential source magnitude and a preset scaling rate; calculating fault distribution parameters of the target potential source area based on the fault size parameters and the mixed seismic source model; combining the three-dimensional longitudinal wave velocity model and the shallow structure model to construct a three-dimensional calculation model; and performing deterministic low-frequency simulation and deterministic high-frequency simulation on the three-dimensional calculation model based on a spectral element method and a three-way stochastic finite fault method respectively, and then performing broadband time program sequence synthesis to obtain a broadband seismic oscillation simulation result. The technical problem of low simulation result accuracy in the prior art is relieved.

The invention discloses a spectral element tearing and splicing region decomposition method embedded with a multi-pole perfect matching layer technology, and the efficiency and precision of seismic wave forward modeling simulation are improved through the fusion of the multi-pole perfect matching layer technology and a region decomposition strategy. The time domain convolution of the multi-pole perfect matching layer is eliminated through a recursion auxiliary equation, the boundary truncation calculation complexity is reduced, glancing waves and long-distance propagation waves are efficiently absorbed, and false reflection is restrained. According to the regional decomposition strategy, a global three-dimensional problem is converted into a two-dimensional interface problem through implicit interface constraint and explicit angular point continuity execution, meanwhile, the explicit calculation advantage of a spectral element method on an angular mass matrix is kept, and rapid solution is achieved without matrix inversion. A load balancing mechanism dynamically allocates tasks of a computational domain and a perfect matching layer, and parallel computing efficiency is guaranteed. The system supports high-order interpolation and large-scale grid division of a complex geologic model, appropriately increases memory consumption, improves engineering practicability, and provides an efficient and reliable simulation tool for deep ground resource exploration.

The invention provides a black triangle scattering noise training sample generation method based on a random medium, and belongs to the technical field of geological exploration. Depicting transverse heterogeneity and longitudinal heterogeneity of the theoretical velocity model; according to a spectral element method numerical stability correlation theory, calculating a time step length and a space step length suitable for the constructed velocity model; calculating an inverse quality factor corresponding to the velocity model, and quantifying the attenuation effect of the complex near-surface on seismic waves; observing whether black triangular noise appears in the shot record under different parameter conditions, and calculating an inverse quality factor of each forward modeling result; the corresponding relation between the inverse quality factor and whether the inverse quality factor is a black triangle or not is arranged, and the generated samples are subjected to label division through the inverse quality factor in combination with the attenuation theory of seismic waves in a random medium. The method is more suitable for actual description and higher-precision numerical calculation, so that a'black triangle 'generation mechanism is researched, and a synthetic training set is not provided by deep learning denoising.

This invention relates to a tunnel full-waveform inversion method based on spectral element forward modeling and physical information neural network, comprising: collecting engineering geological data and obtaining physical property parameters; establishing a two-dimensional finite element model and obtaining spatial information; constructing a wavefield model and performing wavefield forward modeling simulation to obtain synthetic full-waveform data; collecting measured waveform data and preprocessing it, performing time registration and normalization processing on the preprocessed measured waveform data and synthetic full-waveform data, and extracting multiple features; constructing a parameter training set; constructing and training a physical information neural network model, constructing a comprehensive loss function during the training process; and using the physical information neural network model to perform full-waveform inversion. This invention deeply integrates finite element forward modeling, full-waveform inversion, and physical information neural network, taking into account both data fitting and physical consistency, significantly improving the quantitative accuracy and reliability of tunnel advanced geological prediction.

This invention discloses an implicit large eddy wall simulation method based on the high-precision spectral element method. This method constructs an implicit large eddy simulation (SVV-iLES) based on the hp-type spectral element method combined with the spectral viscosity elimination method (SVV), and implements wall simulation within this framework. The method includes the following steps: adjusting the boundary layer according to the actual situation of the turbulent boundary layer to ensure that the corresponding points fall within the logarithmic region; interpolating the element velocity and velocity u within the spectral element method code framework to obtain velocity components parallel to the wall velocity, which are then substituted into the algebraic model; analytically obtaining the wall stress through the algebraic model; and finally, modifying the boundary conditions in real time using the logarithmic rate model to complete the simulation. This significantly reduces the enormous computational burden caused by fine boundary layer meshes in flow problems. This invention also proposes an application of this simulation method to high Reynolds number wall flow scenarios, providing an efficient foundation for accurate flow calculations.

The invention discloses a CFRP structure ultrasonic guided wave propagation time domain spectral element simulation parallel computing method, relates to the technical field of nondestructive testing, and aims to solve the problem of low ultrasonic guided wave propagation calculation efficiency of a large-area composite material plate-shaped structure at present. A multi-node spectrum unit is adopted to carry out grid division on a large-area composite material plate, a grid numbering algorithm is designed to divide a grid into sub-blocks (domain decomposition), subsets of disjoint nodes are created, and a high-order time domain spectrum element method is combined with a compute unified device architecture (CUDA) to realize parallel computing. A step-by-step time integration algorithm based on a central difference scheme is adopted to realize unit-level parallel calculation on a GPU (Graphics Processing Unit) to solve a wave equation, a high-order time domain spectral element method (SEM) is combined with a CUDA (Compute Unified Device Architecture), the calculation efficiency is improved, the propagation calculation of ultrasonic guided waves in a large-area composite material plate-shaped structure can be accelerated, and the calculation efficiency is improved. The composite material plate-shaped structure health monitoring method has a wide application prospect.

The invention discloses a semiconductor electrothermal characteristic simulation method and system based on a spectral element method. The method comprises the following steps: firstly, deducing a mathematical physical model of a semiconductor electrothermal multi-physical field to obtain a control equation set; then, the complete geometric device model is divided into a plurality of grid units with the same size, and each grid unit is constructed into a high-order spectral element method grid unit based on a Gauss-Labatto-Legendre node set; calculating a space vector value in the grid by utilizing an edge value and a spectral element method vector base interpolation, and constructing a unit matrix equation by adopting a windward format spectral element method and time domain backward difference; and finally, traversing all grid units in the solving domain to construct a system matrix equation. According to the method, the edge value is interpolated by adopting the spectral element method high-order vector primary function, the problem of poor edge calculation precision in multi-dimensional problem solving is solved, the convergence is better, and the problem of three-dimensional MOSFET electrothermal coupling can be effectively solved.

The application discloses a seismic simulation method and system fusing an implicit iterative graph network and a spectral element method, obtains small time step node acceleration data; performs grid sparse division and interpolation mapping processing and projects to a low-dimensional manifold to obtain large time step node acceleration data and a low-order unit calculation moment matrix of a current frame; obtains physical relation sparse matrix one, physical relation sparse matrix two and sparse matrix topological relation information of the physical relation sparse matrix one and the physical relation sparse matrix two through Jacobian iteration and projection to a low-dimensional manifold processing method; obtains a seismic simulation graph neural network model; adopts the seismic simulation graph neural network model to perform prediction, and uses a projection matrix to project back to large time step predicted acceleration of a sparse unit node of a target region. The method greatly shortens the calculation time by mapping the high-order unit small time step and the low-order unit large time step through the neural network fitting capability, and realizes fast seismic simulation.

This invention relates to the field of geophysical exploration technology, specifically to a high-precision three-dimensional forward modeling method for airborne electromagnetic spectral elements considering induced polarization effects. Based on the Cole-Cole model, a complex conductivity expression considering induced polarization effects is established, and the frequency domain Helmholtz equation is introduced to construct the corresponding governing equations. A regular hexahedral mesh is generated, and reference domain vector basis functions are constructed using the Gauss-Lobatto-Legendre orthogonal polynomial method according to the spectral element method. The mapping relationship between these functions and physical mesh elements is established. The Galerkin weighted residual method is applied to discretize the governing equations into element system matrices, which are then assembled to form the overall system matrix and the corresponding linear equation set. A direct solver is used to obtain the frequency domain three-dimensional electromagnetic response, and the time domain three-dimensional forward modeling result of the computational region is obtained through Hankel transformation. This invention achieves rapid and high-precision three-dimensional forward modeling simulation of complex geological models containing induced polarization effects.

The invention belongs to the technical field of seismic engineering, and relates to a seismic magnitude calibration method based on a seismic source dynamics mechanism, which comprises the following steps: determining seismic source parameters in a target area, and establishing a dynamic seismic source model according to seismic fault information in the target area; obtaining a digital elevation model (DEM) of a target area, processing DEM data, establishing a three-dimensional site model of the target area, and obtaining geological parameters; and determining a friction constitutive relationship, carrying out high-precision seismic oscillation simulation by adopting a spectral element method on the premise of not changing geometric factors of the model, obtaining seismic oscillation characteristics, determining a proportional coefficient value corresponding to a current fault, and then carrying out magnitude calibration work. Compared with the prior art, the method has the beneficial effects that the calculation efficiency is high, the modeling method is simple, the effectiveness of the calculation result can be improved, and the earthquake magnitude calibration precision can be improved, so that a more reliable scientific basis is provided for disaster prevention and reduction design of regional infrastructures.

The application discloses a neuron action potential conduction simulation method based on a spectral element method, and belongs to the technical field of bio-electromagnetics. The method comprises the following steps: 1) neuron model input; 2) conduction equation construction: a partial differential equation for action potential propagation in a single nerve fiber is established; 3) conduction equation solving: the specific form of the conduction equation established in the step 2) is changed by using the neuron model input in the step 1), and the resting potential is solved by using the spectral element method; 4) the voltage change of each point of the neuron with time is obtained according to time iteration. The spectral element method can simulate the action potential propagation of various forms of neurons, and only the basic parameters of the neuron model need to be imported and the external input is set, so that the propagation process of the action potential in the nerve fiber can be calculated, that is, the voltage change and distribution in and outside the cell membrane in the action potential propagation process. The method has the advantages of fast calculation speed, accurate result, simple operation and the like.

The invention relates to the technical field of electromagnetic full-wave inversion, in particular to a two-dimensional cross-layered efficient electromagnetic full-wave inversion method based on a spectral element boundary integral method.During forward modeling calculation, a scatterer crossing multiple horizontal layers is surrounded by a one-dimensional smooth boundary, and two-dimensional electromagnetic field distribution is solved by adopting a spectral element method in a region; accurately truncating an SEM solving domain on the boundary by using a boundary integral equation; for a transverse electric mode and a transverse magnetic mode, equivalent current / magnetic current is solved by using BIE, and a receiver scattering field is calculated in combination with a layered two-dimensional vector Green function; in the full-wave inversion, in order to reconstruct TE mode isotropic scatterer model parameters and TM mode anisotropic scatterer model parameters respectively, first-order derivatives of a mass matrix and a stiffness matrix relative to the corresponding parameters are calculated respectively, a sensitivity matrix is constructed, and an LM optimization algorithm is adopted to iteratively call an SEBI forward solver to complete inversion; multiple groups of numerical experiments verify the accuracy and high efficiency of the SEBI-LM algorithm in forward modeling and FWI.

The application discloses a kind of ocean sound field parallel simulation methods based on DR-SETD, belong to the technical field of simulation calculation.This application includes: three-dimensional fluid-structure interaction model is simplified to axisymmetric model to reduce the scale of calculation;Adopt high-order spectral element method based on orthogonal polynomial to carry out spatial dispersion, and numerical singularity is handled for axisymmetric property;The weak form of time-domain wave equation of fluid domain and solid domain is respectively constructed, and is solved by interface coupling condition;Efficient parallelization of solving process is realized using explicit time integration format and shared memory parallel computing architecture.This application realizes the high-precision, high-efficiency full-wave simulation of fluid-structure interaction sound field containing complex terrain.

The invention discloses a seismic oscillation simulation method based on a broadband three-component mixing method, and belongs to the technical field of seismic oscillation simulation. According to the method, through a neural network fitting method, a low and medium frequency three-component Fourier amplitude ratio and a relationship between seismic source information and a high frequency seismic oscillation three-component Fourier amplitude ratio are established. The method comprises the following steps of: simulating low and medium frequency three-component seismic oscillation by adopting a spectral element method to predict a high-frequency three-component amplitude ratio, simulating high-frequency three-component seismic oscillation with different amplitudes by adopting an improved random finite fault method, and finally superposing the high-frequency seismic oscillation and the low and medium frequency seismic oscillation by adopting a matched filtering method to predict the amplitude ratio of the high-frequency three-component seismic oscillation. And broadband three-component seismic oscillation capable of reflecting a seismic fracture process, a three-dimensional non-uniform medium and a local site topographic condition is further obtained.

This invention discloses a parallel computation method for time-domain spectral element simulation of ultrasonic guided wave propagation in CFRP structures, relating to the field of nondestructive testing technology. The purpose of this invention is to address the low computational efficiency of current methods for ultrasonic guided wave propagation in large-area composite plate structures. It employs multi-node spectral elements to mesh the large-area composite plate, designs a mesh numbering algorithm to divide the mesh into sub-blocks (domain decomposition), creates subsets of disjoint nodes, and combines the high-order time-domain spectral element method with a Computational Unified Device Architecture (CUDA) to achieve parallel computation. A stepwise time integration algorithm based on a central difference scheme is used to implement unit-level parallel computation to solve the wave equation on a GPU. This method combines the high-order time-domain spectral element method (SEM) with CUDA, improving computational efficiency and accelerating the computation of ultrasonic guided wave propagation in large-area composite plate structures. It has broad application prospects in health monitoring methods for composite plate structures.

The invention discloses a basin-hill coupling site broadband seismic oscillation simulation method and system based on a mixing method, and relates to the technical field of site seismic oscillation simulation, and the method comprises the steps: building a kinematics mixed seismic source model of a to-be-simulated near-fault basin-hill coupling site based on a concave-convex body seismic source model and a random seismic source model; performing low-frequency seismic oscillation simulation on the kinematic mixed seismic source model based on a spectral element method to obtain a low-frequency simulation result; performing high-frequency seismic oscillation simulation on the kinematics mixed seismic source model based on a three-dimensional random finite fault method to obtain a high-frequency simulation result; and combining the low-frequency simulation result and the high-frequency simulation result to obtain a broadband seismic oscillation simulation result of the near-fault basin-hill coupling site to be simulated. According to the invention, the technical problems of high calculation cost and unreliable high-frequency part result in the broadband seismic oscillation simulation process for the near-fault basin-hill coupling site in the prior art are solved.