Simulating and testing a non-contact structural health monitoring system

Abstract

Structural health monitoring (SHM) is a technique which enables the integrity of a physical structure to be analysed in a non-invasive manner, meaning that no structural disassembly needs to take place. In addition to being non-invasive, information gathered using this technique can be immediately available to engineers. This technique can be applied to a number of different types of structures, ranging from buildings, to bridges, to vehicles. The research discussed in this paper is focused on the development of a novel non-line of sight (NLOS) radio frequency (RF) based technique for performing SHM. RF transceivers will be placed at fixed locations on a structure, and by analysing transmitted and reflected signals around the network, the displacements between the transceivers can be computed. These measurements allow for the calculation of interstorey drift ratios (IDRs), which characterise the significance of the movement of a structure resulting from an external force. These IDRs can be used to understand the stress on the system, from which the structure's integrity can be understood. The feasibility of such a technique has been investigated, and the potential signal processing methods to utilise RF in SHM have been evaluated. Frequency-modulated continuous wave (FMCW) radar has been identified as the most suitable method due to its distance resolution and short sampling period. It has also been used in similar applications, demonstrating that the technique is viable in this field. A prototype FMCW system has been developed, and is currently ready for initial testing.