Circular Patch Sensor Based on Distributed Fiber Optic Technology for Tensile and Bending Loads Identification

The design, manufacturing, and preliminary testing of a smart patch sensor named MonitoRing are herein presented. The sensor is conceived to identify amplitude and direction of structural loads by distributed strain profile detection along its circular geometry. The sensor is manufactured by using flexible glass/epoxy laminates hosting a single standard telecom fiber optic. The fiber optic is embedded according to three loops, different by radius and quote. The sensor is then externally bonded on a structural element and able to follow the deformations under tensile and bending loading condition. The optical Rayleigh backscattering technology provides an interrogation of strain with high spatial resolution all along the fiber path. The load and direction identification is hence, provided by comparing amplitude, phase and sign of deformation spectrum of each loop. Preliminary numerical and experimental result, are reported and analyzed for simple test cases