53 results about "Cauchy boundary condition" patented technology

Method for fabrication of vector vortex waveplates of improved quality due to reduced singularity size and widened spectral band, the method comprising creating a boundary condition for vortex orientation pattern of a liquid crystal polymer on a substrate using materials with reversible photoalignment, equalizing exposure energy over the area of the waveplate by redistributing the energy of radiation used for photoalignment from the center of the beam to its peripheries, and using vector vortex waveplate as a linear-to-axial polarization converter. Fabrication of spectrally broadband vector vortex waveplates further comprises two or more liquid crystal polymer layers with opposite sign of twist.

The invention discloses a structural dynamical model modification-based prestress recognition method, and relates to the prestress recognition of pre-tensioning structures. The method comprises the following steps: establishing a finite element model of a structure; converting the boundary condition such as clamped support or simple support into spring support in three or two directions, and applying an axial prestress at the same time; calculating a fixed frequency and a fixed vibration mode of the structure through commercial finite element software; carrying out test and recognition by utilizing a test modal analysis technology, so as to obtain the fixed frequency and the fixed vibration mode of the structure; and recognizing the spring support rigidity and prestress of the boundary at the same time on the basis of a model modification technology. The method is simple, high in recognition precision and convenient to operate; and through considering the influences of the boundary condition, the reliability is high. By taking MAC as a target function, the completeness of the test data is supplemented; the optimization through a genetic algorithm is more beneficial for obtaining the globally optimal solution; and the whole modification model can be automatically driven to carry out solving.

The invention belongs to the technical field of grid computation, and specifically relates to a grid boundary condition processing method of unstructured grid CFD computation. The method comprises the following steps: establishing grid information; defining a boundary type; extracting grid outer boundary information; realizing the matching of a first node through a method of exhaustion; matching the remaining nodes in a wave front form; matching a boundary surface unit; and assigning a boundary condition. According to the method, a method for rapidly matching between unstructured boundary surfaces and grid surfaces is utilized, so that the grid boundary conditions of unstructured grids in Tecplot form can be rapidly mapped to corresponding boundary surfaces of infield body grids, the rapid processing of boundary condition information of the unstructured grids can be realized and the computer time can be effectively decreased.

The invention discloses a new submodel finite element analysis method based on cutting boundary deformation constraint. The content of the method comprises: building a complete machine simplified model, analyzing; carrying out postprocessing to cutting boundary nodes of the complete machine model; building a finite element model-a submodel of a partial structure; adding a deformation coupling constraint equation to the cutting boundary of the submodel, adding a displacement interpolation boundary condition and a force boundary condition; analyzing the submodel; and checking that the distance from a cutting boundary to a stress gathered region is far enough. The method of the invention is advantaged by that when applying the boundary conditions to the cutting boundary of the submodel, the displacement interpolation boundary condition is added to one part of the cutting boundary, the constraint equation and the force boundary condition are added to the other part; the accuracy of the boundary conditions of the submodel is ensured; compared with the traditional submodel finite element analysis method, in adoption of the new submodel finite element analysis method, the demand of the complete machine model is reduced; the complete machine model is greatly simplified; and the complete machine analysis efficiency and the calculation precision of the submodel are improved.

An aspect of the present invention provides a method of carrying out a simulation with simulation data, including, determining whether or not the simulation data includes boundary conditions set for a boundary of a calculation area set for the simulation, computing the influence of the boundary conditions on the inside of the calculation area if the simulation data includes the boundary conditions, displaying the influence of the boundary conditions on the inside of the calculation area, prompting to enter an instruction whether or not the boundary conditions are changed, and if an instruction to make no change in the boundary conditions is entered, carrying out the simulation with the simulation data.

The invention relates to a formwork support system derivative design method. 1. Determine the boundary conditions and calculation steps of the formwork support system; 2, establish a parametric modelaccording to that boundary condition; 3, load and internal force calculation; 4. Checking the stress and displacement of the structure, outputting the calculation result to check whether it meets thedesign requirements; 5, count that engineering quantity of the design scheme; 6, upload that publishing program to the cloud; 7, compute various combinations according with that boundary conditions byusing the cloud computing capability, and obtaining thousands of design scheme; 8, arrange that statistical data of the project quantity according to the calculation result, and comparing and selecting the most design scheme. This method adopts the derivative design principle, according to the set boundary condition scope and the step distance request, compiles the program to construct the model,outputs the stress, the displacement and the project quantity statistical result, utilizes the cloud computing ability, has greatly improved the design efficiency, and reduced the engineering material, saves the cost.

The invention relates to an implementation method for a mixed absorbing boundary condition applied to a variable density acoustic wave equation. The implementation method comprises the steps of dividing a whole simulation region into an internal region and a boundary region, calculating the wave field value of a sound wave of each absorbing boundary layer by using the variable density acoustic wave equation and a variable density AWWE (Arbitrary Wide-angle wave equation) respectively, and performing linear weighting on the two calculation results to obtain the wave field value of the sound wave of each absorbing boundary layer. On the basis of realizing a single variable density AWWE absorbing boundary layer and in 2D (2 dimensional) and 3D (3 dimensional) space coordinate systems, the wave field value of the sound wave of each absorbing boundary layer is calculated by respectively adopting a combination mode of processing edges of the variable density AWWE and processing angles of a modified 15-degree one-way wave equation, and a combination mode of processing faces of the variable density AWWE, the processing edges of the modified 15-degree one-way wave equation and the processing angles of a 5-degree one-way wave equation, and the mixed absorbing boundary condition of the variable density AWWE is realized. The implementation method can be widely applied to the numerical simulation of constant density and variable density acoustic wave equations.

The invention discloses a reverse time migration method of a carbonatite reservoir. By aiming at a phenomenon that a fracture-cavity pore construction of carbonatite is always companied with fracture and big-angle form distortion formed due to construction movement, the reverse time migration method is used for precisely depicting the carbonatite. A finite difference method is used for solving a wave equation to simulate a seismic wave field; a processing method for the wave field to transmit to a boundary adopts a PML (Perfectly Matched Layer) absorbing boundary condition; a seismic origin wave field recovery part adopts a reverse PML wave field recovery technology; and a calculation part adopts a GPU (Graphics Processing Unit) parallel acceleration technology. The PML absorbing boundary condition is adopted, so that the invention can more effectively eliminate boundary reflection interference than a random boundary condition; since the reverse PML wave field recovery technology is adopted, compared with a traditional wave field storage strategy, the invention can greatly reduce requirements on a storage amount on the premise that a calculated amount is not increased, a wave field recovery effect is good, amplitude fading is avoided, and operation efficiency is improved by adopting the GPU parallel acceleration technology.

The invention relates to a night video enhancement method based on gradient integration. Day background frames can be extracted by utilization of spatial constraint conditions and a Gaussian mixture model, and gradient information of day video background frames is integrated into night video gradient images, so the detailed information lost in the night video images can be compensated. Restored images can be obtained by use of a poisson equation and the boundary conditions of the day background frames. The video image brightness is enhanced, and moreover, a color fidelity effect is achieved.

The invention discloses an in-plane thermoelectric device structure design method based on COMSOL software, and the method comprises the following steps: selecting a three-dimensional space dimensionand a thermoelectric effect physical field in a COMSOL software model guide, and carrying out the steady-state research; Establishing a geometric physical model of the thermoelectric device needing tobe solved; Defining related global parameters and endowing model material attributes; Setting an initial value and boundary conditions of the model; Dividing grids and calculating; And changing boundary current conditions, calculating and comparing the boundary current conditions through COMSOL software to obtain the working state of the thermoelectric device under the optimal current, and carrying out post-processing on the obtained result. Numerical simulation of temperature fields of thermoelectric devices of different structures during working is achieved, the temperature field distribution rule of the thermoelectric devices is explored, the experiment cost and time are reduced, and theoretical guidance and technical support are provided for structure optimization of the thermoelectric devices.

The invention provides a thermal analysis modeling method for data extraction, which comprises the following steps of: firstly, establishing a model in finite element software, and dividing grids; secondly, calculating coefficients changing with time changes on the basis of information of the finite element software; thirdly, extracting a constant coefficient matrix without changing with the timechanges on the basis of the finite element software; fourthly, configuring a solving environment; fifthly, setting initial conditions and boundary conditions; and sixthly, resolving the model. When the modeling method is adopted, the powerful modeling and grid-dividing functions of the finite element software can be utilized; the problem of difficulty in establishing a complex model and dividing the grids is solved; the workload of the finite element modeling can be reduced; and complex boundary conditions can be loaded conveniently and quickly.

Computational fluid dynamics modeling of a bounded domain is provided which includes solving iteratively a computational fluid dynamics model of the bounded domain using mass flow boundary conditions that are specified. The solving includes automatically adjusting the specified mass flow boundary conditions for at least one iteration of the solving. The automatically adjusting includes mass balancing flows at a boundary of the bounded domain to provide corrected mass flow boundary conditions for the solving. The mass balancing includes applying different corrections to mass in-flow across the domain boundary, compared with mass out-flow across the boundary. The mass balancing may include multiplying mass in-flows across the boundary by (1−CF), and mass out-flows across the boundary by (1+CF), where CF is a determined correction factor, and net mass flow is positive for mass out-flow exiting the domain, and negative for mass in-flow entering the domain.

This invention relates to, in order to numerically analyze contaminant transport in groundwater, a method of analyzing contaminant transport under Cauchy boundary conditions using an improved Lagrangian-Eulerian method, wherein problems of a conventional Lagrangian-Eulerian method able to analyze only high Peclet numbers are solved, and which is configured to analyze a new numerical matrix constructed in such a manner that a Eulerian method is applied to an element adjacent to Cauchy boundary conditions and a conventional Lagrangian-Eulerian method is applied to an internal element, thereby enabling accurate numerical analysis of contaminant transport at various Peclet numbers including not only high Peclet numbers but also particularly low Peclet numbers under Cauchy boundary conditions.

The invention discloses a simulation acquisition method for friction coefficient of friction plate, comprising the steps ofstep 1) the surface of the new friction plate is subjected to image processing to obtain the micro-topographic features of the friction plate; step 2) set the lattice density of sampling, output the lattice data that describes the characteristic of the surface of the friction layer and perform the interpolation processing to obtain the fitting surface;step 3) three - dimensional model reconstruction is performed on the fitting surface basis; step 4) the imported entities are meshed to obtain the finite element analysis model; step 5) the initial speed, the stop speed, the braking time and the pressure of the friction plate in the actual work is obtained;step 6) the boundary condition of the actual working condition is applied and the friction simulation analysis is carried out and step 7) compare with the actual measured values, constantly correct the simulation boundary conditions. The method can effectively and accurately obtain the friction coefficient of the friction plate, which is simple and has long-term development prospect compared with the physical mapping.

The invention discloses a combined absorbing boundary condition applied to sound wave finite difference numerical simulation, and belongs to the field of seismic exploration numerical simulation. The combined absorbing boundary condition applied to the sound wave finite difference numerical simulation specifically comprises the following steps of: when sound wave equation numerical simulation is performed based on a 2N-order (N>0) accuracy staggered-mesh finite difference scheme, at first, setting L (L>N) perfectly matched layers (PML) at an artificial truncated boundary, and absorbing boundary reflected waves from a central wave field by using a PML boundary condition; and then, for N layers of boundaries outside the PML, by using an Higdon three-order absorbing boundary condition, absorbing outer boundary reflexes of the PML. According to the method provided by the present invention, by fully utilizing the advantages of both the PML boundary condition and the Higdon three-order absorbing boundary condition are fully utilized, the boundary reflexes of inner layers and outer layers of artificial boundaries can be effectively absorbed, thereby achieving high-accuracy finite difference numerical simulation.

The invention provides a settlement calculation method of a multilayer foundation under any load effect. The method includes the steps that 1, a consolidation equation is subjected to Laplace transformation, and an initial boundary value condition and an interlayer continuity condition between multiple layers of the foundation are subjected to Laplace transformation; 2, according to a formula obtained after transformation in the first step, a stress solution coefficient matrix of a specific layer is deduced; 3, a waveform function of any load is subjected to Laplace transformation to serve asa boundary condition in a transformation domain; 4, according to the stress solution coefficient matrix and the boundary condition, a matrix transfer method is adopted, and stress and deformation solutions of all the layers in the Laplace transformation domain are obtained; and 5, the stress and the total settlement of any point can be obtained through a Laplace inverse transformation method. Quantitative calculation and predictive analysis of the settlement rule of the layered foundation under any load effect are achieved, and a scientific and effective basis is provided for design and construction of the foundation under the variable-load effect in engineering.

The invention discloses an airworthiness compliance verification method for a combustion chamber casing. The method comprises the steps of (1) determining a load boundary condition of the combustion chamber casing according to clauses and requirements of CCAR 33.64, and determining a displacement boundary condition according to a constraint situation under an actual working condition; (2) conducting an eigenvalue buckling analysis on the combustion chamber casing, and obtaining eigenvalues and eigenvalue buckling modes under different orders; (3) selecting a first-order buckling instability portion of the casing as analysis focus, and performing a geometrical and material double nonlinear buckling analysis under a condition (1); (4) calculating a stability safety factor as the condition for determining the stability of the casing; (5) using a nonlinear buckling critical load obtained in (3) through analysis as an internal and external gas pressure difference, loading the boundary condition in (1) for a static strength analysis, and determining the compliance of the combustion chamber casing with the airworthiness clauses. The method simultaneously considers the stability and staticstrength of the combustion chamber casing, proposes a targeted verification analysis method, and indicates the airworthiness compliance of the combustion chamber casing.

The invention discloses an automatic partitioning and encryption method for a structural grid. The method comprises the following steps: step 1, grouping grid blocks of an original structural grid according to boundary conditions of the original structural grid; step 2, according to the encryption coefficient, on the premise that the space topology of the original structure grid is not changed, performing encryption reconstruction on the grid block of each group; step 3, reassembling the encrypted and reconstructed groups, and updating boundary conditions among different groups to obtain an encrypted and reconstructed grid; and step 4, checking each item of the encrypted reconstructed grid, and outputting the encrypted reconstructed grid and boundary conditions thereof. According to the boundary conditions of the original structural grid, grouping is automatically carried out, encryption reconstruction is automatically carried out, and the encryption reconstruction grid and the boundary conditions of the encryption reconstruction grid are automatically output, so that automatic block encryption of the structural grid is realized, manual intervention is completely not needed, high efficiency and stability are realized, and errors possibly caused by manual operation are completely eradicated.

The invention discloses a boundary condition classification based multiple fault calculation method, and relates to the technical field of power system fault analysis and calculation. The calculation method comprises the following steps: transforming and recombining original network equations; classifying boundary condition expressions to generalize five transformation rules; adopting the dynamic of the transformation rules to transform the network equations again in order to realize the united solution of complex faults under the condition of fault combination in different multiple numbers and different types. The calculation method is based on the idea of boundary condition classification, carries out classification on boundary conditions of multiple faults in arbitrary multiple numbers, summarizes the transformation rule of each classification of boundary conditions, carries out united transformation on various fault port network equations, solves the combination of various fault boundary conditions and the network equations, realizes unification of the solution process of the complex faults under the condition of fault combination in different multiple numbers and different types, and is easy for computer realization.