Maísa Milanez Ávila Dias Maciel

In response to growing environmental and economic concerns, developing new technologies prioritising safety, sustainability, and reliability has become imperative. In the energy sector, batteries play an increasingly significant role in applications such as powering electronic devices and vehicles. In this context, lithium-ion batteries have raised environmental concerns, driving the exploration of alternative technologies. Sodium-based batteries have emerged as an attractive option due to their environmental and economic advantages, as well as their potential for multi-functional applications. This study investigates a novel battery developed by a research team at the University of Porto, with a specific focus on its strain-sensing capabilities for potential applications in damage detection of structures. The battery under investigation is a novel all-solid-state design, comprised of a sodium-ion ferroelectric electrolyte and zinc and copper as the negative and positive electrodes, respectively. A series of quasi-static and dynamic tests are conducted to qualitatively assess the piezoelectric behaviour of the battery. The consistent findings show that the battery generates a difference in the electric potential in response to mechanical stimuli, thus confirming its piezoelectric nature. Furthermore, the results demonstrate the battery can accurately detect the operating frequencies of a shaker, despite encountering inherent electromagnetic interference noise from the electrical grid during testing. These promising outcomes highlight the substantial potential of this emerging technology for a wide range of applications, including but not limited to structural health monitoring systems. Given its novelty, this technology presents multi-functional capabilities for diverse practical future applications, such as energy harvesting that leads to self-powered structural health monitoring systems.

Variable angle tow composites were developed to increase stiffness in notched laminates. Scientific advancements in manufacturing and fiber path optimization have since improved variable angle tow composites. This study uses bibliometric analysis to track the evolution of variable angle tow composites in the literature. Bibliometric analysis is a useful tool for measuring paper contributions and accurately assessing performance, aiding authors in the research process. This article presents a co-occurrence map of keyword frequency in research papers. Furthermore, an experimental section highlights manufacturing defects found in variable angle tow composites produced by filament winding, showing that manufacturing real structures in variable angle tow composites poses a significant challenge. Lastly, the perspectives of variable angle tow composite applications are discussed.