Piezoelectric materials constitute a class of intelligent materials which are helpful for monitoring the structural integrity. The principle of the piezoelectric impedance-based structural health monitoring (SHM) technique is to measure the electrical impedance of a piezoelectric patch attached to a structure over a certain frequency range. Electrical impedance variations indicate physical changes in the structure due to coupling between the electrical impedance and the mechanical impedance. Traditional methods use an impedance analyzer which increases the inspection cost. The objective of this work is to develop an electronic circuit for the piezoelectric impedance-based structural health monitoring. The circuit, which consists of a digitally-controlled oscillator, a peak detector, a digital-to-analog converter, a differential amplifier, a comparator, counters, and a control circuit, can monitor the electrical impedance variations of a piezoelectric patch attached to a structure. The frequency range is from 7.47 kHz to 277.29 kHz. This frequency range covers the sensitive range of the piezoelectric structural integrity. The circuit design has a power consumption of 18.15 mW, and a chip area of 1.03 x 2.30 mm2. The cost of the final design will be much lower than that of an impedance analyzer. Using a wireless communication circuit, a sensor network connecting several SHM sensors might be established in the future.
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机译：压电材料构成一类智能材料，有助于监测结构完整性。基于压电阻抗的结构健康监测（SHM）技术的原理是在一定频率范围内测量附着到结构的压电贴片的电阻抗。电阻抗变化表明由于电阻抗和机械阻抗之间的耦合，结构的物理变化。传统方法使用阻抗分析仪，这会增加检查成本。这项工作的目的是开发一种用于基于压电阻抗的结构健康监测的电子电路。该电路由一个数字控制振荡器，一个峰值检测器，一个数模转换器，一个差分放大器，一个比较器，计数器和一个控制电路组成，可以监视与之相连的压电贴片的电阻抗变化。结构。频率范围为7.47 kHz至277.29 kHz。该频率范围覆盖了压电结构完整性的敏感范围。该电路设计的功耗为18.15 mW，芯片面积为1.03 x 2.30 mm2。最终设计的成本将比阻抗分析仪的成本低得多。使用无线通信电路，将来可能会建立连接多个SHM传感器的传感器网络。
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