基于时间反演法的纤维增强复材/钢筋增强混凝土梁损伤监测研究

INVESTIGATION OF THE DAMAGE MONITORING OF FRP/STEEL REINFORCED CONCRETE BEAM BASED ON TIME REVERSAL METHOD

为识别纤维增强复材/钢筋(FRP/Steel)增强混凝土梁的损伤发展及损伤机理,采用压电陶瓷传感器对FRP/Steel增强混凝土梁进行损伤监测。利用时间反演法的自适应聚焦性质和良好的抗噪性质,分析四点弯曲加载下梁的损伤程度与归一化聚焦信号幅值的关系。试验结果表明:归一化聚焦信号幅值随着施加荷载的增大而减少;钢筋增强混凝土梁的归一化聚焦信号幅值衰减速度慢于FRP筋增强混凝土梁,说明在同等荷载作用下FRP筋增强混凝土梁的损伤程度大;将归一化聚焦信号幅值与梁的理论刚度指数进行对比发现,归一化聚焦信号幅值与理论刚度指数曲线吻合良好,其能够反映FRP/Steel增强混凝土梁的刚度退化情况。

To identify the damage development and damage mechanism of FRP/Steel reinforced concrete beams,the damage of FRP/Steel reinforced concrete beams is monitored by using piezoceramic transducer in this paper.The relationship between the damage levels and the amplitude of the normalized focusing signal is analyzed based on the adaptive focusing property and the anti-noise property of time reversal technology.The test results show that the amplitude of the normalized focusing signal decreases as a result of the increase of the applied load.The amplitude attenuation rate of the normalized focusing signal amplitude of the steel reinforced concrete beam is slower than that of FRP reinforced concrete beam.This indicates that the damage of the FRP reinforced concrete beam is worse than that of steel reinforced concrete beam under the same applied load;by comparing the amplitude of the normalized focusing signal with the theoretical stiffness index of the beam,it is found that the amplitude of the normalized focusing signal agrees well with the theoretical stiffness index curve,which can reflect the stiffness degradation of FRP/Steel reinforced concrete beams.