A Perspective of Non-Fiber-Optical Metamaterial and Piezoelectric Material Sensing in Automated Structural Health Monitoring

Abstract

Metamaterials are familiar in life sciences, but are only recently adopted in structural health monitoring (SHM). Even though they have existed for some time, they are only recently classified as smart materials suitable for civil, mechanical, and aerospace (CMA) engineering. There are still not many commercialized metamaterial designs suitable for CMA sensing applications. On the other hand, piezoelectric materials are one of the popular smart materials in use for about 25 years. Both these materials are non-fiber-optical in nature and are robust to withstand the rugged CMA engineering environment, if proper designs are adopted. However, no single smart material or SHM technique can ever address the complexities of CMA structures and a combination of such sensors along with popular fiber optical sensors should be encouraged. Furthermore, the global demand for miniaturization of SHM equipment, automation and portability is also on the rise as indicated by several global marketing strategists. Recently, Technavio analysts, a well-known market research company estimated the global SHM market to grow from the current US $ 1.48 billion to US $ 3.38 billion by 2023, at a compound annual growth rate (CAGR) of 17.93%. The market for metamaterial is expected to grow rapidly at a CAGR of more than 22% and the market for piezoelectric materials is expected to accelerate at a CAGR of over 13%. At the same time, the global automation and robotics market in the automotive industry is expected to post a CAGR of close to 8%. The fusion of such smart materials along with automation can increase the overall market enormously. Thus, this invited review paper presents a positive perspective of these non-fiber-optic sensors, especially those made of metamaterial designs. Additionally, our recent work related to near field setup, a portable meta setup, and their functionalities along with a novel piezoelectric catchment sensor are discussed.

Actively MEMS-Based Tunable Metamaterials for Advanced and Emerging Applications

“…By exploiting the mechanical and optical characteristics, MEMS-based metamaterials have been widely used in gas sensing, photo-detecting, flow monitoring, etc. [110][111][112][113][114][115][116][117][118][119][120]. Such sensors can be designed to be sensitive to specific ranges of wavelengths for the requirement of different applications.…”

“…By applying the fluidic flowing pressure, the released MTM cantilevers can be deflected at different bending states and induce the variation range of the resonant frequency to detect the flow rate. The sensing performance of metamaterial can be greatly improved to enlarge the applying fields by using MEMS techniques, such as refractive index sensing, flowing rate sensing, thermo-sensing, photo-sensing, and so on [115][116][117][118][119][120]. The "on" and "off" states microscopic images of the MEMS-based metamaterial array [105].…”

Demonstration of wideband tunability in chalcogenide metamaterials

“…Some recent work has taken advantage of piezoelectric transducers to alter the near-field environment of a metamaterial and thus produce tuning. 8,9 To date, most work has shown small changes in optical properties and provided tuning over a small physical area. For many applications, tuning over large bandwidths and large areas is required.…”