Application of Electromechanical Impedance Technique for Engineering Structures: Review and Future Issues

Lee

Journal of Applied Physics

et al. 2014

Section: On-line Monitoring Fatigue Rate and Fatigue Indexmentioning

confidence: 99%

Fatigue of extracted lead zirconate titanate multilayer actuators under unipolar high field electric cycling

Lee

Journal of Applied Physics

et al. 2014

“…Unlike conventional nondestructive testing techniques, structural health monitoring refers to the process of continuously monitoring the current state of a structure and measuring damage-sensitive data from the sensors that are typically permanently installed on the structure. Nowadays, many researchers are dedicated to piezoelectric transducer (PZT)-based SHM methods [1][2][3][4][5][6] because of their performance in damage diagnosis and their stability against noise from the environment. The PZT-based SHM methods can be divided into two categories: the passive method, where sensors are designed to collect data only, and the active method, where the PZT sensors generate vibration or emit stress waves [7].…”

Section: Introductionmentioning

confidence: 99%

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

Guo

Huang

2020

Applied Sciences

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...

“…Compared with some of the methods mentioned above, EMI is superior in the sensing region, which is in the scale of metres for only one small lead zirconate titanate (PZT) plate. In addition, the damage signatures are easy to extract and online monitoring could be realised [8] . The mechanical behaviour of materials evaluated with the EMI technique has been reported [11][12][13] .…”

Section: Introductionmentioning

confidence: 99%

“…Each one has some particular applications, but the damage that can be evaluated in each case is quite specific. With the development of modal analysis technology, the modal shift has been introduced into current linear acoustic measurement and it is very important that the integral damage could be evaluated [8] . Structural health monitoring based on the electro-mechanical impedance (EMI) technique couples the electrical impedance with piezoelectric material to reflect the mechanical impedance of the host structure.…”

Section: Introductionmentioning

confidence: 99%

Quantitative electro-mechanical impedance evaluation of tensile damage to austenitic stainless steel

Luo¹,

Liu²,

Cao³

et al. 2013

insight

SHMThe mechanical damage of centrifugally cast austenitic stainless steel (CCASS) under tensile stress was quantitatively evaluated by the electro-mechanical impedance (EMI) technique. The influence of loading profiles on the impedance results was investigated. Two frequency bands, 25-65 kHz and 72-112 kHz, were selected and scanned during the intervals of mechanical testing. The resonance frequency shift Δf and root-mean-square deviation (RMSD) of electrical impedance signatures under different damage states were extracted as damage identification indexes. Results show that Δf and RMSD had a good correspondence with the evolution of mechanical damage. In other words, they had small values at the elastic deformation stage, which increased rapidly after the transition to plastic deformation. Δf had an approximately linear relationship to the nominal tensile stress, increasing from about 0.05 to 1.65 kHz until the final failure. The evolution of RMSD values, however, depended on the testing frequency band. The reason for this difference was discussed comprehensively. The impedance results under different loading conditions demonstrated that holding the load in the plastic deformation stage would lower the resonance frequency and thus conceal the genuine damage evolution if the impedance testing was conducted simultaneously. Nevertheless, the influence of elastic deformation under tensile stress was small for the 3 mm-thick CCASS plate.