PhD in Engineering - Passive and power free wireless micro-sensors for structural health monitoring of composite structures

Composite materials are widely used in various sectors such as aerospace, automotive and wind energy. Composite materials are used in various infrastructures due to their weight/strength ratio, durability and feasibility of manufacturing. However, with the use of composite material, structural health monitoring (SHM) of the composite structures becomes an emerging issue. Additionally, many composite structures are designed to be used in hazardous environment or to store aggressive chemicals such as alkaline and acid solutions. In order to maintain the health of composite structure, many SHM methods are being studied such as impedance spectroscopy/tomography (EIS/EIT), acoustic emission, and fibre optics based spectroscopic methods (modified optical fibre, Bragg fibre grating. But all these methods are not convenient. An easier and cheaper method must be developed.
This project aims to innovative develop graphene-based and self-powered piezo-electric SHM sensors fully integrated on composite structures and with wireless communication capabilities. Such sensors offer a comfortable and almost imperceptible way of continuous monitoring, as opposed to heavy and bulky equipment currently in use for the same purpose. Exposed to external stimuli, such as cyclic and impact loadings, the power generation of these sensors will change in a predictable way, and this will be explored for sensing purposes.

This will be achieved by low-power circuits and data storage, with purposely developed signal processing techniques, that can translate the signals, captured by the piezo-electric materials, as simple and understandable engineering data to evaluate the structural integrity. A self-contained and environmentally friendly energy source based on a triboelectric nanogenerator, capable of harvesting energy from the structural movements, will also be developed to provide the power free concept.
The sensor can continuously record the abstracted and important events over the structure’s lifetime for downloading at specified intervals or urgent communication if critical. During this project, the sensors will be developed and validated for impact and fatigue load monitoring. These sensors will be equipped with Radio Frequency Identification (RFID) technology which provides a low powered wireless communication with potential to exploit the Internet of Things (IoT). This is analogous to the smart tags that read details of commercial products. With the IoT-driven device connectivity and technological advancements, these devices enable a hands-free operation and continuous recording of useful data. Integrating sensors on structures, through developing multilaterals 3D printable inks with integrated wireless sensors, would eliminate the inconvenience of attaching hardware. This is very important in the case of SHM as it has to be performed continuously, which requires the prolonged maintenance for installation of sensors and their associated wires.