Structural Health Monitoring System Using Liquid Metal Antenna via Zigbee Wireless Sensor Network

Structures such as roads and bridges are susceptible to experiencing heavy loads which may cause damage or failure. To determine the health of these structures manual inspection and measurements are done which can be inaccurate. To address this issue, the researchers developed a Structural Health Monitoring system that will track the strain imbued within the concrete using a liquid metal antenna, sensing unit, microcontroller, and a computer application. The strain in the concrete affects the resonant frequency of the embedded liquid metal antenna as it stretches or contracts which is then converted into voltage readings by the microcontroller through the sensing unit. Three similar but separate systems are connected to a computer via Wireless Sensor Network in star topology using Zigbee Technology for data acquisition. A computer application is also developed to generate reports of the strain detected by the respective sensors. Test results using the nano-Vector Network Analyzer to obtain the resonant frequency on the antenna and the developed system show a correlation of 0.8, 0.9 and 0.96 which implies a highly linear relationship.