Application And Analysis Of Recurrence Plot In Non-stationary Signals

With the rapid development of the bridge structure health monitoring theory,the analysis and research on the damage identification and load identification of the bridge structures by using the operational vibration response signals collected by the health monitoring system arranged on the bridge has attracted more and more scholars’ attention.Because of the complexity and variability of actual bridge working load and environmental load,the bridge health monitoring signals are essentially non-stationary.Therefore,the first problem to be solved in processing and analysis of the actual bridge monitoring signal is to judge whether the signal is stationary or non-stationary.If the signal is stationary,it can be analyzed by a commonly used stationary signal processing method such as Fourier transform;if the signal is non-stationary,it needs to be further clarified to the extent of its non-stationary.The recurrence plot and its recurrence quantification analysis theory are a new method for analyzing and processing non-stationary signals.In this paper,the recurrence plot and its recurrence quantification analysis method are used to study the non-stationary of the signal,and an evaluation index of the signal non-stationary degree is proposed.Then,the numerical simulation signals and the bridge health monitoring measured vibration signals are used to test the applicability and reliability of the evaluation index.The research has important theoretical significance and engineering practical value.This paper first reviewed a series of references and materials for the recurrence plot and its recurrence quantification analysis theory,and also discussed the theoretical background,research status and application fields of the recurrence plot and its recurrence quantification analysis in detail,and it also outlined the definition,physical significance and construction method of the recurrence plot.Recurrence plot established the recurrence matrix through the phase space reconstruction method of the signal,and expresses the recurrence matrix graphically,visually and intuitively.Recurrence quantification analysis is to analyze and calculate signals by using various typical modes reflecting the characteristics of signals on the recurrence plots,so as to achieve the purpose of quantitative analysis of non-stationary signals.The analog signals are qualitatively analyzed according to the stationary and nonstationary modes in the recurrence plot.On the basis of qualitative analysis,the recurrence quantitative analysis measures based on vertical lines which can reflect the stability of the system are analyzed and compared.The laminarity(LAM)is selected as the evaluation index of non-stationary degree of the signals.The measured vibration signals of the bridge is used to test the applicability and reliability of the non-stationary evaluation index laminarity(LAM).By using the data collected by the health monitoring system of Wuhan Yangluo Yangtze River Highway Bridge which has a collision accident,the selected evaluation index laminarity(LAM)is tested.The vibration signals collected during the collision accident,before and after the collision accident of the bridge are calculated and analyzed,and the evaluation results of the non-stationary degree of the vibration response signals in three different time periods are obtained.From the evaluation results,it can be seen that the laminarity(LAM)can better judge the non-stationary and evaluate the nonstationary degree of the signals.And it can reflect the change of the non-stationary degree of the vibration signals when the bridge is subjected to the collision accident compared with that before and after the collision accident.It is further shown that the proposed the laminarity(LAM)is a reliable index for judging the non-stationarity and evaluating the non-stationarity of signals.