Experimental Evaluation of a Low-Cost RFID-Based Sensor to Crack Propagation

Abstract

A passive radio frequency identification (RFID)-based crack sensor was developed and its sensitivity to crack propagation on metallic plates has been experimentally validated. A crack propagation test method was designed to evaluate any backscatter power-based crack sensor to monitor propagating cracks on a metallic surface. This new method uses plate specimens designed for standard fracture toughness testing. Systematic increases in displacement with a hydraulic universal test machine to propagate the crack were performed. Using digital imagery, the physical characteristics of the crack and fracture mode were determined with high precision. Linear elastic fracture was induced so as to more closely resemble the fracture mode that is to be expected in high strength steel bridge girders. The sensor was tested as a single unit and in various arrays of multiple units for increased pervasiveness in monitoring. A piecewise relationship between the damage index and crack opening was found. This relationship is a significant finding that demonstrates that RFID-based crack sensing is a feasible tool for bridge inspection.