9 results about "Mass matrix" patented technology

A method for rapidly solving transient dynamics of a crack-containing bearing structure of a bogie belongs to the technical field of bogie structure dynamic analysis, and comprises the following steps: acquiring a three-dimensional geometric model of the bearing structure, the geometric dimension of a crack and the position coordinate dimension of the crack; dividing the finite element model of the bearing structure, and carrying out grid division processing on the crack surface; selecting a main degree-of-freedom node of the finite element model on the surface of the bearing structure and the crack surface; performing substructure analysis on the finite element model of the bearing structure; obtaining a mass matrix, a damping matrix and a stiffness matrix of the finite element model of the bearing structure after the degree of freedom is reduced; carrying out constraint simulation on a crack surface node by adopting a one-way nonlinear rigidity unit; processing constraint boundary conditions; processing the excitation load; and solving a dynamic second-order differential equation set, and judging whether the crack surface is in contact or not. According to the method, the opening and closing effects of the crack can be considered, the transient dynamic response of the crack-containing bearing structure under the action of the external load is obtained, and the solving precision and efficiency are both considered.

The invention is suitable for the field of portal frames, and discloses a portal frame dynamics analysis method which comprises the following steps: establishing a full-order finite element model of a portal frame, and obtaining a mass matrix and a stiffness matrix of the full-order finite element model; dividing the full-order finite element model into a plurality of substructures based on the modular structure characteristics of the portal frame, and decomposing the degree of freedom of each substructure into an internal degree of freedom and a boundary degree of freedom; constructing a fixed boundary main modal matrix and a constraint modal matrix of each substructure, and constructing a reduced-order basis matrix; performing modal polycondensation on a mass matrix and a stiffness matrix of the full-order finite element model by using the reduced-order basis matrix to generate a reduced-order mass matrix and a reduced-order stiffness matrix, and constructing a reduced-order kinetic equation; and solving the reduced-order kinetic equation to obtain reduced-order modal coordinates, carrying out inversion reduction in combination with the reduced-order basis matrix and the reduced-order modal coordinates to obtain a displacement response vector of the full-order finite element model, and retaining key kinetic information of the portal frame to the greatest extent through reduced-order efficiency improvement.

The invention discloses a Gaussian splash covariance matrix optimization method based on a Hamiltonian Monte Carlo algorithm, and belongs to the technical field of 3D Gaussian splash modeling. According to the method, a dynamic system is constructed through the Hamiltonian Monte Carlo algorithm, a dynamic equation is further constructed to improve and optimize the processing capacity and processing precision of a covariance matrix on Gaussian ellipsoid parameters in 3D Gaussian splashing, and the Gaussian ellipsoid parameters are obtained through the modes of constructing Hamiltonian amount, introducing momentum variables, simulating dynamics through a leapfrog method and the like. A brand new covariance matrix optimized by a quality matrix is realized and obtained, and an optimization and analysis method of a Gaussian splash covariance matrix based on a Hamiltonian Monte Carlo algorithm is provided. Meanwhile, a peak signal-to-noise ratio (PSNR) evaluation mechanism is provided and is used for quantifying the optimization result.

The application discloses a kind of quick solution method for the transient dynamics of bogie containing crack bearing structure, belongs to bogie structure dynamic analysis technical field, it includes: obtaining the three-dimensional geometric model of bearing structure, crack geometric dimension and the position coordinate size of crack;Divide bearing structure finite element model, crack surface is carried out grid division processing;On the surface of bearing structure and crack surface, select the main degree of freedom node of finite element model;Substructure analysis is carried out to bearing structure finite element model;Obtain the mass matrix, damping matrix and stiffness matrix of bearing structure finite element model after reducing degree of freedom;Crack surface node is simulated by using one-way nonlinear stiffness unit and is constrained;Processing constraint boundary condition;Processing excitation load;Solve the second-order differential equation set of dynamics, judge whether crack surface occurs contact or not.The application can consider the opening and closing effect of crack, obtain the transient dynamics response of bearing structure containing crack under external load, and give consideration to solving precision and efficiency.

The application discloses a kind of multi-body multi-coupling characteristics of floating structure hydrodynamic analysis method, comprising the following steps: obtaining the geometric characteristics of each floating body, dividing boundary element calculation grid;Calculate each floating body wave exciting force, additional mass and radiation damping, obtain the mass matrix and stiffness matrix of each floating body;Determine the connection mode and coupling factor of floating body;According to the connection mode and coupling characteristics of system, establish the displacement connection condition between each floating body;According to displacement continuous condition and motion constraint relationship, construct motion constraint matrix;According to Lagrange multiplier method, determine the frequency domain motion equation of multi-floater system;Solve motion equation, obtain the motion response of multi-floater system, according to the coupling characteristics of system, further system's analysis wave energy capture power.According to the above analysis method, the present application can solve the problem that the existing simulation method cannot accurately depict the motion response of each degree of freedom when obtaining the hydrodynamic response characteristics of complex multi-body system.

The invention discloses a propeller system performance prediction and vibration suppression method based on a shell unit, and the method comprises the steps: firstly determining the structural parameters and geometric information of a propeller blade, and generating corresponding nodes and unit numbers through employing uniform grid division; on the basis, a finite element model is established, a stiffness matrix and a mass matrix of each unit are calculated, and then a kinetic equation of the system is constructed. Through modal analysis, the inherent frequency and vibration mode characteristics of the blade are obtained, and a key vibration mode is identified. And performing dynamic response analysis by using an external load condition, and outputting a response curve of each node and vibration characteristics of key nodes. And finally, adjusting design parameters through a parameter sensitivity analysis and optimization technology so as to effectively suppress vibration and improve performance. The method provides an effective tool for dynamic characteristic analysis and optimization design of the propeller.

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.

This invention discloses a method, system, device, and medium for forward calculation and performance prediction of acoustic superstructures, relating to the field of vibration reduction and noise reduction technology. The method includes: constructing a finite element model of periodic elements to obtain the stiffness and mass matrices; introducing periodic boundary conditions to transform the wave control equations into a nonlinear eigenvalue problem of complex wavenumbers; employing a contour integral algorithm to solve all characteristic wavenumbers and corresponding generalized eigenvectors in one step within a pre-set closed contour in the complex wavenumber plane; automatically matching and tracking characteristic wavenumbers of the same physical wave branch based on eigenvector similarity in the target frequency domain, and plotting a continuous dispersion curve; identifying vibration bandgap based on the dispersion curve, recovering the generalized eigenvectors to physical space for wave mode analysis, and completing performance prediction. This invention overcomes the computational efficiency bottleneck of traditional methods in complex element and mid-to-high frequency analysis, reveals the wave coupling mechanism of bandgap generation, and provides core support for topology optimization of acoustic superstructures.

The invention discloses a novel bolt flange structure analytical model and a verification method thereof, and belongs to the technical field of numerical analysis and computational mechanics. The method comprises the following steps: discretizing and modeling a bolt flange structure; deriving a unit stiffness matrix, a unit mass matrix and a unit inertia matrix for the rotor system; calculating the equivalent stiffness of a bolt for connecting the upper flange plate and the lower flange plate, wherein the equivalent stiffness comprises the axial stiffness and the shearing stiffness of the bolt and the stiffness of the joint surface of the connected flange plates; establishing a complete system kinetic equation of the bolt flange structure; and verifying the model. The problem that an existing method excessively depends on a simplified model or numerical simulation or experience statistics is solved, and a theoretical basis is provided for forward design and performance optimization of a connection structure.