| With the booming of construction industry,modern construction technology is a fantastic time to launch innovation.In this background,concrete-filled tube has met people demands for higher building,more widely open space and more safe usability than the buildings used to be.We get benefits from it’s excellent mechanical properties and ductility so that prevent building damage form earthquake and other disasters.Therefore,CFTC play a significant role in the constructions,which means it was a key point whether could we identify the damages.But in reality,debonding damage is a factor to lower CFTC mechanical properties.The purpose of this article is try to find an effective way to judge debonding injury of CFTC and locate the place of debonding damage.This paper analysed the non-stationary characteristics of CFTC vibration signals to choose sensitive indexes to detect debonding damage.The signal strength of dominant mode of vibration(SS),determinism(DET)and entropy(ENTR)of vibration signal were chosen as judgement indexes.This article study process could be separated into four parts:(1)AMD(Analytical Mode Decomposition)is an adaptive time-frequency analysis method,and is was widely used in non-linear and non-stationary signal analysis.This part took into consideration analytical errors which included length of time series and interception bandwidth of mode analysis in AMD method,and set pretreatment programs to reduce the influence,which meant that standardized treatment could get more accurate decomposed signals than used to be.(2)When we undertook the signals non-stationary characteristics analysis,timefrequency was a key process.This part we applied AR model(Autoregressive model)to estimate power spectrum.Compared with Fourier spectrum,it is better in anti-noise property and identification precision.At same time,the paper cooperated AR model with optimized interception bandwidth method could enhanced analysis efficiency.(3)Designed L16＿4＿5 orthogonal experiment to research different damage case of CFTC by finite element dynamic analysis,and described the connections between research factors and dynamic characteristics under different boundary conditions.This part not only guided experiment design,but also ensured sensitive indexes of nonstationary characteristics for damage detection primarily.Due to SS was used to analyse the signals of longitudinal sensor stations,the extent of damage and height would take different interference to detecting precision.To aiming this situation,DET and ENTR were added to analyse the signals of horizontal sensor station which located in damage side and non-damage side.Combined parameters analysis could avoid distortion of results at adverse conditions.(4)Designed 5 experiment under different damage situations to verified the effectiveness of combined parameters.The results show that it acted out good performance in many complicated environments,and located the damage place successfully.The paper based on modern analysis method,finite element dynamic analysis and experiment to advance a damage detection method for debonding damage of CFTC.And the method acted out good performance in actual conditions. |
