基于压电陶瓷的钢管混凝土柱剥离损伤识别研究

设计和制作了一个局部区域存在模拟界面剥离损伤的矩形钢管混凝土柱,将压电陶瓷片用水泥砂浆封装制成驱动器,预埋入钢管混凝土柱混凝土内部,在信号源产生的正弦扫频电压信号的作用下产生激励信号,同时在钢管外壁不同区域粘贴压电陶瓷片作为传感器,测量具有模拟剥离损伤的钢管混凝土柱四个监测面上压电陶瓷片传感器的输出电压。分别对位于完好界面和模拟剥离损伤区域压电传感器输出信号进行了小波包总能量和小波包能量谱分析。发现完好区域小波包能量谱相对于小波包总能量而言离散性更小,且与压电陶瓷位置和应力波传播路径无明显关系。而剥离区域的小波包能量谱具有明显的差异,在此基础上提出了基于小波包能量谱的加权相对变化损伤指标,基于该指标对试验模型的界面损伤区域进行了准确识别。将该方法用于某超高层建筑的大截面钢管混凝土柱的混凝土质量和界面粘结性能的评估中,分析结果表明该钢管混凝土柱的混凝土质量和界面间接性能良好。本文所提出的方法为监测钢管混凝土柱内部混凝土与钢管壁粘结状况提供了一种新的思路。

Detection of the debonding defect of concrete-filled steel tubes with piezoceramics

A novel debonding defect detection method for concrete-filled steel tube(CFST) structures using lead zirconate titanate(PZT) is proposed and tested with a lab CFST specimen.By embedding PZT based functional smart aggregates(SAs) in concrete as actuators and pasting PZT patches on the predetermined locations of the outer surfaces of the CFST specimen as sensors,the debonding areas of the CFST specimen are detected based on the wavelet package energy and wavelet package energy spectrum of the measurement of the PZT patches.Results show the wavelet packet energy spectrum of each PZT sensor on bonding area has no obvious scatter,but obvious variation when PZT patches are located in the debonding area.Based on the wavelet packet energy spectra,a damage index called Weighted Energy Ratio Variation(WERV) is defined and the artificially mimicked debonding areas are detected successfully based on the WERV.Results show that the defined indexes are sensitive to the debonding damage.The proposed approach is employed to assess the quality of concrete and the bonding condition of the interface of a large cross-section CFST column of a super high-rise building.This proposed debonding defect detection method provides a novel way for the monitoring of debonding defect of CFSTs.