Passive Wireless Sensor for Displacement Monitoring in Metal Structures

Technologies for the monitoring of structural components, such as strain gauges and fiber optics, are commonly used when information is sought on the state of displacements that a structural component is subjected to. Both techniques require cabling, producing various adversities in their applications. Thus, new wireless technologies have been gaining space for remote monitoring, either through antennas or through unmanned aerial vehicles. Wireless sensors, using radio frequency identification (RFID) technology, are attractive means of getting around some of these adversities. These sensors are formed by an antenna and an integrated RFID component. When attached to a component subject to external loading it will deform. This deformation will lead to a change in its resonance frequency. In this way, depending on the type of load, there will be a response change. For the development of the sensor, the Taconic TLY-5 material was used, with which a label was conditioned using a nationally manufactured RFID component (CI). For the validation of the sensor, a numerical study was carried out by the finite element method (FEM) and, after the sensor was made, a mechanical tensile test on the plate. As the displacements are applied, the reading distance data is collected and related. The data obtained in the simulation showed a linear relationship between displacement and resonance frequency. Experimental results show s similar trend. From these results it seems that the sensor can be a good alternative for monitoring structures in which large displacements are applied.