Structural parameter identification method for two-degree-of-freedom system based on vibration response signal

Abstract

The invention relates to a structural parameter identification method for a two-degree-of-freedom based on a vibration response signal. The content of the structural parameter identification method comprises the steps of performing structural excitation, and acquiring a vibration displacement signal; acquiring a natural frequency and a natural angular frequency of each order of the system by applying FFT (Fast Fourier Transform); decomposing the vibration displacement signal by using a rapid empirical model decomposition method so as to acquire a plurality of intrinsic mode function (IMF) components; solving an instantaneous frequency of each IMF component, comparing the instantaneous frequency of each IMF component with the natural frequency acquired by FFT so as to screen out IMF components capable of representing the natural frequency of the system; processing the screened IMF components by applying Hilbert transform, acquiring each slowly-varying amplitude and slowly-varying phase angle of a vibration response, and performing parameter correction; and substituting known parameters into an identification model to solve, solving an average value, and acquiring structural parameters of the system. The structural parameter identification method can simultaneously utilize time-frequency domain information of data, is high in anti-noise capacity and can directly utilize vibration response data to perform parameter identification.

Description

technical field [0001] The invention belongs to the field of structural parameter identification, in particular to a method for identifying structural parameters of a two-degree-of-freedom system based on vibration response signals. Background technique [0002] Structural parameters have an important impact on system dynamics modeling and vibration control, and it is of great engineering significance to accurately and effectively identify the structural parameters of the system. In system vibration analysis and control, it is often necessary to identify the physical parameters between certain parts or parts of its constituent structures. In general, it is relatively easy to establish a mathematical model of each individual component of the system, but it is difficult to obtain structural parameters such as connection stiffness and damping of the interface between components, and it cannot be directly measured, making it difficult to obtain the entire structural system. Dyn...

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Problems solved by technology

[0003] The traditional parameter identification method is divided into time domain method and frequency domain method, which cannot use the time domain and frequency domain information of the data at the same time, resulting in the limitation of the accuracy of parameter identification

Moreover, the traditional parameter identification method must measure the excitation signal and the response signal at the same time, but in practical engineering applications, especially for large structures, it is difficult to obtain the input excitation in the presence of complex environmental excitation.

In addition, traditional modal parameter identification methods are sensitive to noise, and most of them can only deal with steady-state signals

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