基于台阵观测记录的结构强震反应时频分析反卷积方法及应用

Strong motion records from structural seismic response observation arrays are of strong non-stationarity, as they contain complex information about the non-stationarity of strong ground motion and the non-linearity of structural dynamic response. The high-resolution time-frequency analysis of structural seismic response accelerograms to identify the slight changes of the structrual vibration modal parameters, could help evaluate the non-linear behaviors of materials, plastic deformation, and cumulative damage of structure buildings under strong ground motion..Referring to the application of deconvolution in the resolution improvement of quadratic time-frequency distributions, this program is designed to remove the weighted moving average effect of wavelets on the energy distribution of structural seismic response accelerograms in time-frequency domain by deconvolution. The deconvolution of the time-frequency amplitude distributions for structural seismic response accelerograms after continuous wavelet transform (or S transform) and the time-frequency amplitude distributions for wavelets themselves, could reconstruct the energy distribution of structural seismic response accelerograms in time-frequency domain with much higher temporal resolution and much higher frequency resolution at the same time. By this suggested higher-resolution time-frequency analysis, several strong motion records from structural seismic response observation arrays accompanied by structrual damages will be analyzed, in order to reveal more details of structural vibration modals varying during earthquakes，and to identify the variant process of natrual frequencies and modal damping ratios from the first to higher-order vibration modals according to the time-frequency distributions of structural seismic response accelerograms on different floors from the basement to the roof.

结构强震反应观测台阵记录中包含了强地震动非平稳性和结构动力反应非线性的综合信息，具有强非平稳性，对其进行高分辨率时变分析以识别结构振动模态参数随时间的细微变化，可以为评价建筑结构在强地震动作用下的材料非线性、塑性变形与累积损伤提供依据。. 本项目拟参照反卷积在提高二次型时频分布分辨率中的应用，通过对连续小波变换（或S变换）后的结构强震反应记录时频幅值分布与小波基自身的时频幅值分布进行反卷积计算，以此消除小波基在时频分析窗口内对结构振动能量分布的加权移动平均作用，从而以更高的时频分辨率重构结构振动能量在时频域内的分布。本项目将对多组伴有结构破坏的结构强震反应观测台阵记录进行高分辨率时频分析，通过分析不同楼层处结构振动能量的高分辨率时频分布揭示结构振动模态时变特性的更多细节，特别是较高阶振动模态参数随时间的变化，识别结构第一阶至较高阶振动模态对应的自振频率和模态阻尼比随时间的变化历程。

结构强震反应观测台阵记录中包含了强地震动非平稳性和结构动力反应非线性的综合信息，具有强非平稳性，对其进行高分辨率时变分析以识别结构振动模态参数随时间的细微变化，可以为评价建筑结构在强地震动作用下的材料非线性、塑性变形与累积损伤提供依据。本项目参照反卷积在提高二次型时频分布分辨率中的应用，通过对连续小波变换后的结构强震反应记录时频幅值分布与小波基自身的时频幅值分布进行反卷积计算，以此消除小波基在时频分析窗口内对结构振动能量分布的加权移动平均作用，从而以更高的时频分辨率重构结构振动能量在时频域内的分布。同时，利用小波滤波来消除频率截断造成的吉布斯现象，以获得稳定的时频分布。对伴有结构破坏的Millikan图书馆和超高层建筑Figueroa at Wilshire大厦的结构强震反应观测台阵记录进行了高分辨率时频分析，通过分析不同楼层处结构振动能量的高分辨率时频分布揭示结构振动模态时变特性的更多细节，特别是较高阶振动模态参数随时间的变化，可识别结构第一阶至较高阶振动模态对应的自振频率随时间的变化历程。