Improved random perturbation method on the basis of repetition frequency structure vibration characteristic value of agent model

Abstract

The invention discloses an improved random perturbation method on the basis of a repetition frequency structure vibration characteristic value of an agent model. The method comprises the following steps: firstly, carrying out perturbation analysis on the characteristic value of a repetition frequency structure, and obtaining a matrix equation in regard to the first-order perturbation amount of the free vibration characteristic value of an original repetition frequency structure after parameters including the rigidity, the quality and the like of the repetition frequency structure are subjected to disturbance and change; and then, on the basis of a polynomial chaos expansion method, constructing an agent model in regard to the first-order perturbation amount of a repetition frequency characteristic value; and combining a perturbation method with an agent model technology on the basis of the polynomial chaos expansion, putting forward an improved approximate calculation method of the free vibration characteristic value of the repetition frequency structure, and further obtaining the expressions of a mean value and a variance under the parameter disturbance situation of the repetition frequency structure characteristic value on the basis of the approximate calculation method. The improved random perturbation method solves the problem in the traditional perturbation method that the statistical characteristics of the traditional perturbation method can not be further researched since the first-order perturbation amount of the repetition frequency structure characteristic value can not be expressed by an explicit expression.

Description

technical field [0001] The present invention is applicable to the eigenvalue analysis of the repetition frequency structure system, and is used to solve the statistical characteristics and variation range of the eigenvalues ​​of the repetition frequency structure system under the condition of various parameter disturbances. The present invention can be used for the repetition frequency structure system Provides guidance on eigenvalue analysis techniques, structural analysis, model updating, and design optimization. Background technique [0002] Repeated frequency systems or dense frequency systems often appear in engineering practice, such as stratospheric airships, airplanes, and large rockets. Especially for spatially flexible structures, one of the main characteristics of their free vibration is that the natural frequencies appear repeatedly or densely. Repetition frequency is the phenomenon that the natural frequencies overlap in the actual engineering structure. In eng...

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Problems solved by technology

However, at present, domestic and foreign scholars mostly focus on the perturbation method based on the Taylor series expansion. When dealing with the repetition frequency eigenvalue, because the derivative of the eigenvalue is not unique, the analysis process encounters difficulties

Therefore, there is still little research work on the use of perturbation methods to deal with the eigenvalue problem of repetition frequency structures

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