基于环境振动信号的框架结构震后损伤识别

提出了一种新的损伤指标用于框架结构的震后损伤识别.以环境振动作为激励信号,采用小波包分解理论,利用框架结构损伤后振动信号的能量在频域内的变化,构建损伤指标DI,并给出了损伤识别流程图.在此基础上,以某钢筋混凝土框架结构为例,设定4种震后损伤工况,对框架结构进行了震后损伤识别分析,探讨了不同楼层、不同类型振动信号对损伤识别效果的影响.结果表明:本文构建的损伤指标DI可以有效识别框架结构的震后损伤,损伤指标DI与损伤程度之间有近似线性的关系;基于较高楼层振动信号的损伤指标值对结构的损伤识别效果较佳;利用速度信号可获得比加速度信号更好的识别效果.

Damage Identification of Frame Structure after Earthquakes Based on Environmental Vibration Records

To address the damage identification problem of frame structures after earthquakes, a new damage identification method based on the wavelet packet decomposition was proposed.The structural vibration signal under environmental vibrations was used to constitute damage indicator (DI) as follows: the vibration signal was decomposed into each frequency band with wavelet packet decomposition, then, a damage indicator was established on the basis of the energy ratio variation on frequency domain.On the above basis, a 3D finite element model of a frame structure was created by calculating DI using the proposed method.The influence on the damage identification of different floors and different types of excitation was discussed.The results show that the DI proposed can be used to identify damage effectively and the DI value is approximately linear to the damage degree.Damage identification based on vibration signal of higher floor is better than that of lower floor and the damage identification effect with velocity signals is better than acceleration signals.