基于压电效应的纤维高性能混凝土损伤监测研究

以纤维掺量为变量制作48个混凝土试件,压电陶瓷传感器作为信号激励器和信号接收器置于混凝土试件表面。基于压电效应对玄武岩-聚丙烯纤维增强高性能混凝土(BPHPC)的损伤进行实时监测。通过对单掺、混掺纤维混凝土的压电应力波信号进行分析,得到基于小波包分析法的损伤指数(DI),并拟合出纤维掺量-荷载-DI的函数关系。结果表明:通过外观损伤状态和压电应力波信号变化定性评价试件的健康状态,纤维的掺入能够降低混凝土的外观损伤程度;单掺纤维混凝土的试件应力波信号幅值比混掺纤维混凝土试件大;玄武岩纤维体积掺量为0.15%、聚丙烯纤维体积掺量为0.10%时试件的DI最小,当DI超过0.8时,可以认为试件被完全破坏;试验数据和试验现象吻合良好,通过压电陶瓷实时监测BPHPC损伤有较高的可行性。

Damage Monitoring of Fiber Reinforced High Performance Concrete Based on Piezoelectric Effect

The 48 concrete specimens were prepared with fiber content as variable. Piezoelectric ceramic sensors as signal exciter and signal receiver were placed on the surface of concrete specimen.The damage of basalt-polypropylene fiber reinforced high performance concrete (BPHPC) was monitored in real time based on piezoelectric effect. The damage index (DI) based on wavelet packet analysis method was obtained by analyzing the piezoelectric stress wave signals of concrete specimens with single and hybrid fiber, and the function relationship of fiber content-load-DI was fitted. The results show that the health state of specimens can be evaluated qualitatively by observing the damage state of appearance and the variety of piezoelectric stress wave signals. The addition of fiber can reduce appearance damage of concrete. The amplitude of stress wave signals of concrete specimens with single fiber is larger than that of concrete specimens with hybrid fiber. When the volume content of basalt fiber and polypropylene fiber is 0.15% and 0.10%, respectively, DI value is the smallest. When DI exceeds 0.8, the specimen is considered to be completely destroyed. The test data is in good agreement with the test phenomena, which indicates that it is feasible to monitor the damage of BPHPC in real time through piezoelectric ceramics.