基于嵌入压电技术的钢管混凝土界面缺陷检测

Experimental Study on Interface Debonding Detection of Concrete-filled Steel Tubular with Embedded PZT

钢管混凝土构件的钢管对核心混凝土的约束是二者共同工作的基础,钢管壁与混凝土的界面剥离将削弱钢管对混凝土的约束效应,进而影响构件的承载力和延性等力学性能。利用外贴于钢管壁的压电陶瓷作为传感器和嵌入式压电功能元作为驱动器,本文提出了一种基于压电陶瓷波动测量与分析的钢管混凝土构件界面剥离损伤监测方法。对比健康状态下简谐激励下测量信号幅值和扫描激励下小波包能量的差异,定义了基于测量信号幅值和小波包能量的损伤指标。结果表明,利用所提出的压电监测技术和所定义的损伤指标,有效地识别了钢管混凝土构件的界面剥离损伤,损伤指标对损伤程度敏感。

The confinement effect of steel tubular on concrete core of concrete-filled steel tubulars( CFSTs) plays key roles on the behavior and the debonding defect between the steel tubular and the confined concrete core can weaken the confinement and decrease the mechanical characteristics including load-carrying capacity and ductility. In this study,an interface debonding detection approach based on the measurement and analysis on the stress wave propagating across the interface is proposed and verified experimentally with the assistance of piezoelectric ceramic( PZT) sensors bonded on the surface of the steel tubular and PZT based function elements embedded in concrete as actuators. Based on the amplitudes and the corresponding wavelet packet energy values when sinusoidal and sweep signals are used,two evaluation indices are defined.Test results show that the proposed method is effectively to identify the debonding defect and the defined indices are sensitive to the extent of interface debonding defects.