【摘要】 提出了一种探测仿真混凝土结构内部损伤的压电波动传感方法,并通过仿真混凝土梁的构件试验对其有效性进行了验证。将压电传感器埋置在仿真混凝土梁中,采用正弦线性扫频激励来驱动特定位置的压电陶瓷传感器,将其他位置的压电传感器作为探头接受弹性波信号,实现对仿真混凝土构件的损伤检测。试验中,分别对完好和不同损伤程度下的仿真混凝土梁进行扫描,通过对接收信号的时域、频域和小波变换分析,识别仿真混凝土梁损伤的出现和发展。结果表明:在仿真混凝土梁中一定传播距离内,信号幅值变化、频率偏移和基于小波包分析的损伤指数对构件的损伤十分敏感,这些数据的变化趋势可以有效地反映构件的损伤程度,可将这类压电传感器用于混凝土坝动力模型试验的损伤监测研究。更多还原

【Abstract】 A method for detecting internal damage in emulation concrete structures was presented in this study.The effectiveness of this method was verified by an emulation concrete beam test.The piezoelectric sensors were embedded in the emulation concrete structures.A piezoelectric sensor in the specific position is selected as the actuator,while the other sensors are the receivers.A designated linear sweep sine excitation was used to drive the actuator.The variations in the measurements between the healthy state and the damage state were used to detect the damage in the structures.The received data were analyzed in time and frequency domain.And also,a wavelet based method was proposed to extract the damage-sensitive features in this study.The results show that the changes in amplitude,frequency and damage index based on wavelet packet analysis is very sensitive to damage of components.These data change trends can effectively reflect the damage extent of components.It is indicated that this kind of piezoelectric sensor can be used to damage monitoring research on dynamic model test of concrete dam.更多还原