Laboratory of Reinforced Concrete and Seismic Design of Structures, Civil Engineering Department, School of Engineering, Democritus University of Thrace, 67100 Xanthi, Greece.
Structural Science and Technology Division, Architectural Engineering Department, School of Engineering, Democritus University of Thrace, 67100 Xanthi, Greece.
Sensors (Basel). 2021 Jan 20;21(3):679. doi: 10.3390/s21030679.
The utilization and effectiveness of a custom-made, portable and low-cost structural health monitoring (SHM) system that implements the PZT-based electro-mechanical admittance (EMA) methodology for the detection and evaluation of the damage of flexural reinforced concrete (RC) beams is presented. Tests of large-scale beams under monotonic and cyclic reversal-imposed deformations have been carried out using an integrated wireless impedance/admittance monitoring system (WiAMS) that employs the voltage measurements of PZT transducers. Small-sized PZT patches that have been epoxy-bonded on the steel bars surface and on the external concrete face of the beams are utilized to diagnose damages caused by steel yielding and concrete cracking. Excitations and simultaneous measurements of the voltage signal responses of the PZT transducers have been carried out at different levels of the applied load during the tests using the developed SHM devices, which are remotely controlled by a terminal emulator. Each PZT output voltage versus frequency response is transferred wireless and in real-time. Statistical index values are calculated based on the signals of the PZT transducers to represent the differences between their baseline response at the healthy state of the beam and their response at each loading/damage level. Finite Element Modeling (FEM) simulation of the tested beams has also been performed to acquire numerical results concerning the internal cracks, the steel strains and the energy dissipation and instability parameters. FEM analyses are used to verify the experimental results and to support the visual observations for a more precise damage evaluation. Findings of this study indicate that the proposed SHM system with the implementation of two different PZT transducer settings can be effectively utilized for the assessment of structural damage caused by concrete cracking and steel yielding in flexural beams under monotonic and cyclic loading.
介绍了一种定制的、便携式且低成本的结构健康监测（SHM）系统的利用和有效性，该系统采用基于 PZT 的机电导纳（EMA）方法，用于检测和评估弯曲钢筋混凝土（RC）梁的损伤。使用集成的无线阻抗/导纳监测系统（WiAMS）对大尺寸梁进行了单调和循环反向变形下的测试，该系统采用 PZT 换能器的电压测量。将小型 PZT 贴片用环氧树脂粘结在梁的钢筋表面和外部混凝土面上，用于诊断由钢筋屈服和混凝土开裂引起的损伤。在测试过程中，使用开发的 SHM 设备在不同的施加荷载水平下对 PZT 换能器的激励和电压信号响应进行了同时测量，这些设备由终端仿真器远程控制。每个 PZT 输出电压与频率的响应都通过无线实时传输。根据 PZT 换能器的信号计算统计指标值，以表示它们在梁的健康状态下的基线响应与每个加载/损伤水平下的响应之间的差异。还对测试梁进行了有限元建模（FEM）模拟，以获得有关内部裂缝、钢筋应变以及能量耗散和不稳定性参数的数值结果。有限元分析用于验证实验结果并支持视觉观察，以进行更精确的损伤评估。本研究的结果表明，所提出的 SHM 系统结合两种不同的 PZT 换能器设置的实施，可以有效地用于评估单调和循环荷载下弯曲梁中由混凝土开裂和钢筋屈服引起的结构损伤。
