Structural damping ratio identification method based on wind-induced vibration non-stationary response

Abstract

The invention discloses a wind-induced vibration non-stationary response-based structural damping ratio identification method, which comprises the following steps of: extracting a wind-induced vibration non-stationary response and performing spectral analysis, identifying a frequency result with the maximum energy in a non-stationary vibration power spectrum, and filtering non-stationary vibration data by adopting a positive and negative band-pass filter within a certain range; calculating an upper envelope line of the filtered non-stationary vibration response data, searching a plurality of local maximum values of the upper envelope line, and determining the position of the last descending section from the last local maximum value to the upper envelope line with a certain length; the inverse Fourier transform of the cross-spectrum density of the conjugate spectrum of the data of the last descending section of the filtered non-stationary vibration is calculated to construct an impulse response function, the normalized constructed impulse response function is fitted by adopting an under-damping single-degree-of-freedom system exponential decay function, and a damping ratio fitting value in fitting parameters is a recognition result. According to the method, the online intelligent recognition of the structural damping ratio with high standardization degree and large automation potential is realized.

Description

technical field [0001] The invention relates to a structure damping ratio identification method based on the non-stationary response of wind-induced vibration, and belongs to the field of structural intelligent monitoring, detection and evaluation. Background technique [0002] Damping is an important property of engineering structures to resist vibration, and damping ratio is an important parameter to describe the damping properties of structures in vibration engineering. The identification of damping ratio is an issue that is widely concerned in the industry. However, due to harsh test conditions, strong variability of identification results, and low degree of automation of identification, the accurate and rapid identification of structural damping ratio has not been well realized. With the development of testing, transmission and computer technology, the wind-induced vibration response of the structure throughout its life can be measured and processed in real time. The n...

AI Technical Summary

Problems solved by technology

The commonly used structural damping ratio identification methods are as follows: (1) Using the excitation method, the structure is pulse-excited with a hammer (for small structures) or a heavy vehicle (for large structures), based on the excitation data and the response of the structure after excitation The data is used to estimate the frequency response function and identify the damping ratio. This method needs to eliminate the influence of the surrounding environment on the structural vibration, and needs to measure the excitation data and response data at the same time. The application conditions are harsh; Or the response data of structural service loads such as vehicles under the natural excitation, construct the estimated impulse response function, and identify the damping ratio. Although this method eliminates the measurement step of the excitation load, the variation of the natural excitation is strong, and the vibration amplitude in the natural excitation response There is continuous external energy input in the ascending section, resulting in inaccurate and large variability in the identified damping ratio, requiring a relatively stable automatic identification method

In summary, although the existing technology can effectively identify the structural damping ratio in theory, the actual operation conditions are harsh, the accuracy is low, the variability is strong, and the automation potential is insufficient.

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