8 results about "Finite element equation" patented technology

The invention relates to the technical field of computer-aided engineering, in particular to a nonlinear efficient iterative solving method for thermal strain load, which is used for solving an obtained finite element equation by using a modified Newton-Raphson method and comprises the following steps of: firstly, establishing a geometric model to be analyzed and performing grid division; the method comprises the following steps: firstly, setting a model to be analyzed, then setting boundary conditions and temperature field change conditions of the model to be analyzed, finally, inputting the conditions into an algorithm solver, solving a nonlinear equation set, iteratively inputting a load continuously according to a modified Newton-Raphson method in the solving process, calculating node displacement until convergence, and solving stress-strain conditions in the welding process according to a material constitutive relation. In the solving process, by judging the size of the two norms of the displacement increment obtained in the adjacent increment step heuristic stage, the convergence of nonlinear solving of the structure is enhanced through the calculation mode, and the solving speed of the nonlinear problem in the thermal elastic-plastic constitutive structure is increased.

The present application belongs to the technical field of numerical simulation of laser directed energy deposition, and relates to a numerical simulation method for the influence of process parameters on the temperature field of laser directed energy deposition of Inconel 718. When calculating the transient temperature field distribution in the process of laser directed energy deposition, the present application needs to complete the definition of material properties, the establishment of a geometric model and mesh division, the establishment of a transient temperature field control equation, the application of a heat source, the application of initial conditions and boundary conditions, the discrete processing of a transient temperature field finite element equation set, latent heat processing, and iterative solving of several parts of work. The numerical simulation method of the present application studies the temperature distribution law in the process of laser directed energy deposition of Inconel 718 material, analyzes the influence of process parameters on the temperature field, establishes and perfects the theoretical basis of laser directed energy deposition of Inconel 718 material, and guides the formulation of process parameters, which has important scientific research significance and engineering application value.

This invention belongs to the field of computer vision and non-rigid point cloud registration technology, and specifically to a scale-adaptive non-rigid point cloud registration method based on gradient decoupling. It includes the following steps: S1: Solving for the stiffness matrix and node multimodal eigenvectors; S2: Solving for the optimal matching point index and robust weights; S3: Solving for the scale gradient and deformation gradient; S4: Solving for the updated scaling coefficients. This invention achieves parameterized separation of scale mismatch and local physical deformation by explicitly introducing a continuously differentiable scale factor into the physical finite element equations and combining it with a spatial orthogonal gradient decoupling strategy. This not only solves the problem of numerical convergence instability caused by misjudging "volume expansion" in traditional methods when scale mismatch occurs, but also ensures that the algorithm maintains stable registration accuracy under scale disturbances.

The application relates to a kind of transient load under the function gradient porous structure of multiphase filling dynamics topology optimization method and system, belong to the topology optimization design field of function gradient porous structure.The technical problems to be solved by the application are: how to fully exploit design space, construct the efficient function gradient porous structure of multiphase filling dynamics topology optimization method, realize the optimal anti-vibration design of porous filling structure with high-quality transient dynamic performance.Technical points: based on characteristic orthogonal decomposition method, the reduced transient dynamic finite element equation of function gradient porous multiphase filling structure is constructed;the material interpolation model and volume constraint model of function gradient porous multiphase filling structure are constructed, and the transient dynamic multiphase filling topology optimization reduced model with the minimum dynamic compliance as the optimization objective is proposed;the reduced sensitivity time-domain accompanying equation is constructed, and the sensitivity of dynamic compliance and volume constraint is efficiently calculated;based on ADMM-MMA hybrid optimization algorithm, the optimal topology design of function gradient porous multiphase filling structure is efficiently solved and obtained.The application can maximize the optimal anti-vibration performance of function gradient porous filling structure, and is especially suitable for the structure lightweight anti-vibration design of large engineering equipment.

The present application belongs to the field of structural deformation reconstruction, and specifically discloses a structural deformation reconstruction method and system based on a four-node inverse plate shell element containing a drilling degree of freedom, comprising: discretizing the structure into a plurality of four-node inverse plate shell elements, and constructing a shear strain matrix by using a discrete shear gap method; kinematically constraining the drilling degree of freedom by using a continuum mechanics rotation field, solving the continuum medium rotation by deriving the global coordinate system from the natural coordinate system shape function, and supplementing the sixth degree of freedom of the element around the normal line; deriving a coordinate transformation matrix based on the assigned sixth degree of freedom, introducing a node coordinate system, transforming the element stiffness matrix to the node coordinate system, and then transforming it to the global coordinate system; and finally, incorporating the above construction method into the least squares functional framework, assembling the global inverse finite element equation by minimizing the error between the theoretical strain and the measured strain, and reconstructing the full-field displacement of the structure. The present application can realize high-precision deformation reconstruction of complex stiffened plate shells and large-curvature structures.

The application discloses a ground penetrating radar time domain finite element fast simulation method, system and equipment. The method comprises the following steps: setting geometric parameters and electrical parameters of a two-dimensional complex geoelectric model; constructing a weak form of a two-dimensional electromagnetic wave equation; forming a time domain finite element equation; establishing a linear equation group after central difference time discretization; giving a time step, judging whether the time step meets a CFL stability condition, if yes, directly solving the linear equation group, if not, performing LU decomposition on a coefficient matrix of the linear equation group, and disturbing unstable eigenvalues in the coefficient matrix until absolute values of all eigenvalues of the decomposed coefficient matrix are less than or equal to 1, and generating a reconstruction coefficient matrix; and solving the reconstructed linear equation group, so that the time step breaks through the CFL stability condition. The application can improve the simulation precision of the ground penetrating radar.

The invention belongs to the technical field of structural finite element data processing, and particularly relates to an iterative solution method and device for a finite element equation set of a whole machine structure. The method comprises the steps of obtaining a complete machine structure sparse positive definite stiffness matrix and a load vector applied to a complete machine structure, and constructing a complete machine structure finite element equation set used for representing the relation among the complete machine structure sparse positive definite stiffness matrix, the load vector and a displacement vector; performing degree-of-freedom elimination on the sparse positive definite stiffness matrix of the whole machine structure to obtain an independent degree-of-freedom matrix; performing bandwidth optimization sorting on the independent degree-of-freedom matrix to obtain a sorted stiffness matrix; processing the sorted stiffness matrix based on an algebraic multi-grid preprocessor to obtain a preprocessed sub-matrix; and calculating a displacement vector by adopting a conjugate gradient iteration method according to the pre-processing sub-matrix. According to the method, the problem that the sparse matrix of the aviation structure is not converged in iterative solution can be effectively solved, and the solution efficiency is remarkably improved while the calculation precision is ensured.

The application discloses a kind of gear dynamic engagement stiffness calculation methods, comprising: obtaining the geometric parameters of gear pair, material attribute and gear motion state parameter;Calculate overall stiffness matrix, overall mass matrix, overall damping matrix and overall external load matrix;Establish the dynamic analysis finite element equation when gear engagement, solve the dynamic vibration displacement of engagement point at different time by using average acceleration method;According to dynamic vibration displacement, the dynamic stiffness of two gears in gear pair is calculated, and single-tooth engagement stiffness is obtained;According to the coincidence degree of gear pair, single-tooth engagement stiffness is superimposed to obtain dynamic engagement stiffness;Also disclosed is a kind of device, including motion state module, three-dimensional scanning module and processing module.The application is based on finite element method, not only considers the influence of angular position change on engagement stiffness, but also considers the influence of gear speed on gear engagement stiffness, more truly reflects the dynamic characteristics of gear when transmission, so that the calculation result is more accurate.