Method and device for identifying operating modal parameters of linear time-varying structure and application of the device

Abstract

The invention relates to method for identifying operating modal parameters of a linear time-varying structure based on memory-restricted principal component analysis. According to the method, the operating modal parameters of a dynamical system with time-varying structural characteristics can be identified by only using unsteady vibration response signals, the operating modal parameters of the structure are identified, and the dynamical variation characteristics of the system can be effectively monitored in real time, thus the method can be applied to vibration control, equipment fault diagnosis, health monitoring, and system structure analysis and optimization. The method is characterized in that the parameter characteristics of the system are identified by only using actual measured response signals, load signals aren't measured, and the method is proven according to mathematical theoretical analysis and experiment, so that a physical significance is endowed to the method. The invention further relates to an operating modal measuring device based on the method, and the device is used for measuring vibration response signals and identifying the operating modal parameters to obtain the real-time online dynamical characteristic change of the system structure, thus the device can be applied to fault diagnosis and health monitoring analysis of a large complex engineering structure (bridge, rail and the like).

Description

technical field [0001] The present invention relates to a time-varying linear structural working modal parameter identification method based on limited memory principal component analysis, and the application of the method in structural fault diagnosis and health state monitoring, and also relates to a time-varying linear structure based on limited memory principal component analysis. A variable linear structure working mode parameter identification device. Background technique [0002] The analysis of vibration characteristics of structures is highly valued in the fields of aerospace vehicles, submarines, civil engineering, ships, automobiles, etc., especially the modal analysis. Modal analysis provides an effective way to study various vibration characteristics. Accurate identification of modal parameters (modal frequency, mode shape, damping ratio) is an important guarantee for the safety and maintainability of the system structure, and an important method for structural...

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Problems solved by technology

Scholars at home and abroad have also done a lot of research on this problem. For example, McLamore et al. used the peak method to extract the modal frequency based on the fast Fourier transform, but this method has the problem of not being able to identify dense modes; the subspace method proposed by Kalman et al. , using matrix decomposition and other methods to extract the signal subspace to obtain an equivalent system, this method is suitable for parameter identification of linear time-varying structures under stationary excitation, and has a certain anti-interference ability to output noise, but the determination of the order of the stochastic subspace model It is relatively cumbersome, with a large amount of calculation, and it is easy to identify false modes; there are also methods such as wavelet transform and Hilbert-Huang transform based on time-frequency analysis, which analyze signal characteristics from both time domain and frequency domain, but these methods are a It is difficult to make a complete analysis of the overall characteristics of the system, and for dense mode problems, due to the limitation of filtering ability, the recognition accuracy is easily affected

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