With capability of achieving structural state awareness and facilitating preventative maintenance schemes, the global market of structural health monitoring (SHM) is growing at an expected compound annual growth rate of 14.5 percent from 2020 to 2027. From a long run, the increasing adoption of internet of things (IoT) and digital twins are transforming the physical world in a wider range into virtual representations. This will sustain the technical advancement and market growth of SHM in the future. As the most commonly applied non-destructive testing method without radioactive hazard, the application of ultrasonic technology in SHM is currently far from the same level of popularity. The important reasons include the bulky size and mass of ultrasonic transducers, and inconsistency in acoustic coupling between the host structure and individual transducers usually manually installed. To overcome the challenges, our group has developed piezoelectric polymer coatings and lead-free piezoelectric ceramic coatings, with processing scalability over large area and conformability on curved surface. Low profile ultrasonic transducers and transducer array have been designed and produced in-situ on the host structure using the piezoelectric coatings, such as via direct-write process. In collaboration with our research and industry collaborators, guided wave-based ultrasonic SHM functions are being demonstrated on planar and tubular structures, including detections of various defects from presence of cracks to plastic deformation. The features and opportunities of these piezoelectric coating transducers in-situ produced for ultrasonic SHM will be discussed.
Screen-printing processes offer advantages in producing directly patterned and integrated piezoelectric elements, and fill an important technological gap between thin film and bulk ceramics. However, several existing problems in the screen-printed piezoelectric thick films, such as the poor reliability and the required high sintering temperature, are significantly limiting their applications. In this work, lead zirconate titanate (PZT) ceramic films of 30 μm in thickness were deposited on Pt-coated silicon substrates by the screen-printing process, in which the ceramic pastes were prepared through a chemical liquid-phase doping approach. Porous thick films with good adhesion were formed on the substrates at a temperature of 925°C. Stable out-of-plane piezoelectric vibration of the thick films was observed with a laser scanning vibrometer (LSV), and the piezoelectric dilatation magnitude was determined accordingly. Our piezoelectric measurements through the areal displacement detection with LSV exhibited distinct advantages for piezoelectric film characterization, including high reliability, high efficiency, and comprehensive information. The longitudinal piezoelectric coefficients of the thick films were calculated from the measured dilatation data through a numerical simulation. High piezoelectric voltage constants were obtained due to the very low dielectric constant of the porous thick films. The application potentials of our screen-printed thick films as integrated piezoelectric sensors are discussed.
A 3D model of one type of micro pumps was supposed and analyzed using finite element method (FEM). The pump had square shape cavity and was driven by a square shape PZT component. The finite element analysis (FEA) took into consideration of the effects of PZT component dimensions, membrane thickness, pump chamber pressure and other geometric parameters. Modal analyses were also conducted. Compression ratio of the pump chamber was taken as the prime parameter for the analyses. It was found that the membrane thickness and the PZT plate thickness played major roles in determining the compression ratio. For each membrane thickness, there was always an optimum PZT plate thickness that gave the maximum compression ratio. Curves showing the relationship between the optimum PZT plate thickness and the membrane thickness at different chamber pressures were given, based on the FEA results. A set of optimum pump design parameters was proposed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.