NURBS isogeometric analysis method for analyzing energy density field of medium-high frequency vibration structure

Abstract

The invention discloses an NURBS isogeometric analysis method for analyzing an energy density field of a medium-high frequency vibration structure. Firstly, an isogeometric analysis model of a designdomain is established; a design domain is described by utilizing an NURBS curve, an NURBS curved surface and an NURBS body; an energy density control equation in a steady state is constructed; a unitenergy density control equation matrix form is constructed; and then an energy density control equation based on an NURBS primary function is calculated, adaptive processing is finally performed, theenergy density control equation obtained by transformation under an isogeometric analysis framework is substituted into kinetic analysis calculation of the structure, and an energy density response atany position in the structure under high-frequency excitation is obtained through solution calculation. Based on an isogeometric analysis framework, starting from an energy density control equation in a steady state, the energy density subjected to time and space averaging is used as a research object, and an energy finite element method is adopted to carry out dynamic analysis on a mechanical structure, so that the shackle of vibration wavelength is eliminated in grid division during analysis, and the precision is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of structural dynamic analysis, and in particular relates to a geometric analysis method such as NURBS for analyzing the energy density field of a medium-high frequency vibration structure. [0002] technical background [0003] Structural dynamic analysis under complex working conditions, especially under high-frequency excitation, has always been a concern in engineering. The traditional method represented by classical finite element can solve the problem of dynamic analysis of complex structures under high-frequency excitation. The performance of the spacecraft is often unsatisfactory; taking the spacecraft as an example, because the spacecraft is subjected to complex excitations such as impact, pulsation, and noise during flight, the vibration frequency caused by the aerodynamic noise outside the fairing can reach above 10,000 Hz. For such a high-frequency For the structural dynamics analysis problem, the...

AI Technical Summary

Problems solved by technology

[0003] Structural dynamic analysis under complex working conditions, especially under high-frequency excitation, has always been a concern in engineering. The traditional method represented by classical finite element can solve the problem of dynamic analysis of complex structures under high-frequency excitation. The performance of the spacecraft is often unsatisfactory; taking the spacecraft as an example, because the spacecraft is subjected to complex excitations such as impact, pulsation, and noise during flight, the vibration frequency caused by the aerodynamic noise outside the fairing can reach above 10,000 Hz. For such a high-frequency For the structural dynamics analysis problem, the modal of the structure is dense, and relative to the scale of the whole system, the structure is dominated by short-wave vibration. When using traditional dynamic analysis methods for analysis, in order to ensure the accuracy of the analysis, a sufficiently small network must be divided. In addition, the finite element analysis model is only an approximation of the geometric model rather than an exact representation, and the dynamic response of the system is highly sensitive to the structural parameters at high frequencies. The accuracy of the analysis results has a huge impact; the split between the geometric model and the analysis model leads to a large amount of time spent in the step of dividing the mesh for approximate expression during analysis and calculation, especially when facing complex structures similar to spacecraft, the finite element method In order to meet the simulation accuracy, a very fine grid must be divided, resulting in excessive calculation costs, causing a contradiction between analysis accuracy and solution efficiency, and prone to large errors, so the traditional method represented by the classical finite element method is difficult to be effective Dynamic analysis of complex structures at high frequencies

Images