Development of a Piezoelectric Transducer-Based Integrated Structural Health Monitoring System for Impact Monitoring and Impedance Measurement

Abstract

Structural health monitoring (SHM) techniques, which are also considered as online nondestructive testing methods, are significant in modern structural engineering due to their ability to guarantee structure safety while reducing maintenance cost. It is often necessary to combine different SHM methods to achieve a more reliable damage detection result. However, the hardware of the SHM systems is usually expensive, bulky, and heavy when they are designed separately. Therefore, this paper proposes a three-layer architecture for designing an integrated multi-function SHM system to achieve a small, lightweight, and low power consumption SHM system. Based on the architecture, an integrated SHM system with impact monitoring and electromechanical impedance measurement is developed. In addition, a scheduling module is developed to manage the two functions of the system. Furthermore, an integrated interface is developed to transfer the data and the command. Then, an integrated printed circuit board is designed and manufactured to achieve the aforementioned functions. The designed system is applied for impact monitoring and damage detection for a supporting structure of a sailplane. Another active sensing technique is based on electromechanical impedance (EMI) [2,8], which can be applied on a composite material [12]. The theoretical model for the EMI method was first established by Liang et al. [13]. In this model, the electrical impedance, which is the inverse of the electrical admittance, of a PZT sensor is shown to be coupled with the mechanical impedance of the host structure. Thus, the measured impendence from PZT can represent the severity of damage in the host structure. However, there are some practical issues related to the application such as debonding issues, temperature effects, and so on [14]. Usually, equipment employed for measuring electric impedance includes an inductance-capacitance-resistance (LCR) meter or impedance analyzer [15]. This hardware, including Agilent 4194A and Wayne Kerr 6500B [16], and so on, is often employed in experiments. Researches using this hardware tend to focus on some practical issues and theoretical problems and pursue a high level of precision; thus, reducing energy consumption and weight of hardware is not considered in these studies. Moreover, some of SHM systems utilizing EMI methods require a set of PZTs to form a sensor network, and this causes the hardware system to become heavy and complex. Therefore, it is necessary to design a lightweight and low-power consumption hardware system for real applications. One way to shrink the size of the hardware system is to employ a chip named AD5933. The AD5933 impedance converter is a high-precision impedance converter system with an on-board frequency generator, a 12-bit 1MSPS, ADC, and an on-board digital signal processing (DSP) engine processing a discrete Fourier transform (DFT) with a weight of less than 5 g. Nowadays, it is employed by many researchers for designing low-cost, on-board, and wireless SHM systems [4]. The next gen...

Piezoelectric Materials and Sensors for Structural Health Monitoring: Fundamental Aspects, Current Status, and Future Perspectives

“…The transducers have two functionalities: passive detection of impacts and active damage assessment using guided Lamb waves. Guo et al proposed a piezoelectric transducer-based integrated SHM system for impact monitoring and impedance measurement [ 106 ]. A “scheduling module” method is utilized to schedule the commands to the PZT sensors and transfer their signals to different preprocessing units for impact detecting or EMI measurement.…”

Experimental Evaluation of Miniature Impedance Board for Loosening Monitoring of the Threaded Pipe Connection

“…The evaluation board can measure the impedance signatures up to 100 kHz with 512 maximum data points. Due to these distinguishing advantages, much research had been published around this low-cost, on-board SHM system [14][15][16][17][18][19]. For example [20], investigated the influence of the calibration process of the AD5933 on impedance measurements and validated its damage detection ability in carbon fiber reinforced polymer CFRP panels suffering delamination [21].…”

Digital Ultrasonic Sensing Device with Programmable Frequency: Development and Analysis

“…However, the device uses an analog filter and does not have the option to select cut-off frequency. Guo et al [16] has successfully shown the possibility of digitizing the sensor with microcontroller usage. However, the author uses the IC AD5933, a high precision impedance converter system with inbuilt digital signal processing capabilities.…”