Shape estimation with distributed fiber Bragg grating sensors for rotating structures

This study investigates shape estimation of rotating structures using displacement-strain relationships and strain data measured with distributed fiber Bragg grating (FBG) sensors. A displacement-strain transformation based on a modal approach is applied to a beam model, and the locations of the strain sensors are optimized by minimizing the condition number of the displacement-strain transformation matrix. In a numerical simulation of a rotating beam, the beam shapes are successfully estimated using the proposed displacement-strain transformation. Experimental validations for transient and steady rotations of the beam are also performed. The estimated shapes of the rotating beam on the basis of FBG signals are compared with the directly captured shapes from photographs taken with a high-speed camera. The results show very close agreement, demonstrating the potential of the proposed shape estimation technique based on displacement-strain transformation using FBG sensors.