Method for extracting modal parameter from viscous damping vibration signals

Abstract

The invention discloses a method for extracting a modal parameter from viscous damping vibration signals. The method for extracting the modal parameter from the viscous damping vibration signals comprises the steps that firstly, Nyquist uniform sampling is conducted on the vibration signals; secondly, an autoregression matrix equation is established through sampled signals, the least square solution of the autoregression coefficient vector of the autoregression matrix equation is worked out, a Prony polynomial is established with all the elements of the least square solution as coefficients, and the polynomial is solved so that the solution vector of variables can be obtained; thirdly, the solution vector is corrected, and an inherent frequency vector containing a false modality and an inhehrent damping ratio vector are worked out according to the corrected solution vector; fourthly, a matrix is established with the corrected solution vector as the basis, sparse optimization solution is conducted on the projection equation on the matrix through the sampled signals, and then a sparse vector is obtained; finally, the false modality is removed through the sparse vector, wherein all the nonzero elements in the sparse vector are vibration mode coefficients. The method for extracting the modal parameter from the viscous damping vibration signals has the advantages that the noise immunity is high, and the extracted modal parameter is high in precision and high in stability.

Description

technical field [0001] The invention relates to a vibration signal processing technology, in particular to a method for extracting modal parameters in viscous damping vibration signals. Background technique [0002] The modal analysis in the vibration signal has important application value in the fields of structural dynamic characteristic analysis, health monitoring, and structural flaw detection. Among them, the extraction of modal parameters is in a basic position. How to accurately extract modal parameters has always been a concern of scholars. . There are currently many modal parameter extraction methods. For the modal parameter extraction in viscous damped vibration signals, the most simple, convenient, and widely used method is the single-input single-output (SISO) method, and the representative one is the complex exponential (CE) method. , many methods are based on the complex exponential method. The complex exponential method is simple to calculate, requires less ...

AI Technical Summary

Problems solved by technology

The complex exponential method is simple to calculate, requires less data, and has high extraction accuracy when the noise of the vibration signal is low, but this method will no longer be applicable as the noise increases, so in practical applications, the vibration signal needs to be analyzed in advance. Eliminate the noise, and then use the complex exponential method to extract the modal parameters. However, if the prior noise elimination effect is not good, the error of the modal parameters extracted by the complex exponential method will be large.

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