6 results about "Virtual displacement" patented technology

The application discloses a bearingless permanent-magnet thin-slice motor radial displacement sensor detection deviation correction method capable of accurately calculating eccentric direction and distance and quickly correcting through suspension current, and comprises the following steps: based on Maxwell stress tensor method and virtual displacement method, mathematical models of controllable suspension force of the bearingless permanent-magnet thin-slice motor and unbalanced magnetic pull caused by eccentricity in a rotor coordinate system are derived respectively; the suspension current is divided into two types of anti-eccentricity and anti-disturbance, and decoupling between eccentric distance and corresponding suspension current components is realized; with the aim of eliminating anti-eccentricity current, the eccentric direction and size are judged by extracting m-axis and n-axis suspension current components to determine a compensation point, and a cycle algorithm of step tracking minimum current is introduced near the compensation point. The application can correct the rotor static eccentricity phenomenon caused by the radial displacement sensor, effectively improve system efficiency and reduce temperature rise speed, and has the characteristics of short time consumption, low cost and high accuracy compared with existing methods.

This invention discloses a smoothed finite element adjustable damping implicit integral algorithm for underwater transient acoustic scattering, belonging to the field of underwater transient acoustic scattering numerical simulation technology. First, the computational domain of the underwater transient acoustic scattering field is discretized into a standard quadrilateral element mesh to construct an interpolation scheme for the sound pressure field. Then, each quadrilateral element is divided into multiple smooth domains, and the smoothed sound pressure gradient matrix is ​​obtained through acoustic generalized gradient smoothing technology. Combining differential control equations, the virtual displacement principle, and the Galerkin weighted residual method, the system matrix equation is constructed. An adjustable damping implicit time integral algorithm is used to complete the time-domain discretization, and the numerical results of the transient acoustic scattering field in the entire time domain are obtained through recursive solution. This invention can soften the "overly stiff" stiffness matrix to reduce spatial discretization errors, suppress high-frequency errors through adjustable numerical damping matching, and achieve coordinated control of spatiotemporal errors. Under the same mesh, its accuracy is superior to the standard finite element method, providing an efficient and reliable solution for underwater transient acoustic scattering engineering simulation.

The present application relates to the technical field of finite element simulation analysis, and specifically discloses a large bearing capacity earthquake-temperature self-adaptive viscous damper and a simulation calculation method, which comprises the following steps: S1: establishing a three-dimensional solid model of a temperature deformation joint and a viscous damper with a stiffness adjusting valve; S2: obtaining a finite element model of the three-dimensional solid model; S3: obtaining a critical speed and a load working condition speed of the viscous damper, and establishing a multi-state self-adaptive stiffness adjusting model of the viscous damper based on the ratio of the load working condition speed to the critical speed; S4: obtaining a time difference value of the stiffness adjusting valve from the start of closing to the complete closing, and establishing a virtual displacement quantification model; S5: adding the multi-state self-adaptive stiffness adjusting model and the virtual displacement quantification model to the finite element model; and S6: performing mechanical simulation analysis on the finite element model. The present application can accurately simulate the complex mechanical behavior of the damper under the conditions of multi-state switching, virtual displacement effect and bidirectional earthquake reciprocating action.

The present application relates to the technical field of structural deformation shape reconstruction, and particularly relates to a new method of inverse finite element deformation reconstruction based on virtual deformation field physical constraint. The method uses the virtual displacement field obtained by inverse finite element reconstruction of sparse strain as the strain extrapolation physical constraint; adopts the iterative idea to use the extrapolated strain and the measured strain for inverse finite element deformation reconstruction again to obtain the new virtual displacement field, so as to constrain the strain extrapolation again. Thus, the virtual deformation and the extrapolated strain are reconstructed iteratively, and the real structural deformation is finally reconstructed; the accuracy of the deformation characteristic value is determined based on the actual measured actual deformation characteristic value and the deformation characteristic value determined based on the extrapolated strain data, and the deformation reconstruction state is determined based on the accuracy. In the deformation reconstruction process, the present application iteratively extrapolates the strain measuring points and uses the virtual displacement field as the physical constraint, so as to improve the accuracy of the deformation reconstruction.

The invention relates to the technical field of finite element simulation analysis, and particularly discloses a large-bearing-capacity earthquake-temperature self-adaptive viscous damper and a simulation calculation method, and the method comprises the steps: S1, building a three-dimensional entity model of a temperature deformation joint and a viscous damper with a rigidity adjusting valve; s2, obtaining a finite element model of the three-dimensional solid model; s3, the critical speed and the load working condition speed of the viscous damper are obtained, and a multi-state self-adaptive rigidity adjusting model of the viscous damper is established based on the ratio of the load working condition speed to the critical speed; s4, acquiring a time difference value of the rigidity adjusting valve from closing to complete closing, and establishing a virtual displacement quantification model; s5, adding the multi-state adaptive stiffness adjustment model and the virtual displacement quantification model into the finite element model; and S6, carrying out mechanical simulation analysis on the finite element model. According to the invention, complex mechanical behaviors of the damper under multi-state switching, virtual displacement effect and bidirectional earthquake reciprocating action can be accurately simulated.

The application relates to a method for quickly obtaining the shear modulus of a material, which comprises the following steps: obtaining a virtual field method basic equation, wherein the virtual field method basic equation contains material stiffness coefficients; expressing the material stiffness coefficients as a basic coefficient expression; reasonably constructing a virtual deformation field under the condition that a real strain is known, controlling the value of the basic coefficients, simplifying the problem, so that the basic coefficient expression of the virtual field method basic equation is equal to a unit matrix, and obtaining a stiffness coefficient expression; simulating a real strain field by using a finite element method, and substituting the simulated real strain field and a virtual displacement field expression into the stiffness coefficient expression to obtain an equation group; solving the equation group, substituting the solution into the virtual displacement field expression, obtaining a virtual displacement field, actually measuring a real strain field, and obtaining the shear modulus according to the virtual displacement field, the real strain field and the virtual field method basic equation. The shear modulus of the material can be accurately and quickly obtained, and the defects of the traditional method, such as complexity, tediousness and high cost in obtaining various material parameters by multiple tests, are avoided.