Strain Transfer Function of Distributed Optical Fiber Sensors and Back-Calculation of the Base Strain Field

Abstract

Distributed optical fiber sensors are a promising technology for monitoring the structural health of large-scale structures. The fiber sensors are usually coated with nonfragile materials to protect the sensor and are bonded onto the structure using adhesive materials. However, local deformation of the relatively soft coating and adhesive layers hinders strain transfer from the base structure to the optical fiber sensor, which reduces and distorts its strain distribution. In this study, we analytically derive a strain transfer function in terms of strain periods, which enables us to understand how the strain reduces and is distorted in the optical fiber depending on the variation of the strain field. We also propose a method for back-calculating the base structure’s strain field using the reduced and distorted strain distribution in the optical fiber sensor. We numerically demonstrate the back-calculation of the base strain using a composite beam model with an open hole and an attached distributed optical fiber sensor. The new strain transfer function and the proposed back-calculation method can enhance the strain field estimation accuracy in using a distributed optical fiber sensor. This enables us to use a highly durable distributed optical fiber sensor with thick protective layers in precision measurement.

Multilayered Composites with Modulus Gradient for Enhanced Pressure—Temperature Sensing Performance

“…Rapid advances in flexible pressure sensors are driving interest in electronic skin [ 1 , 2 , 3 , 4 ], electronic textiles [ 5 , 6 , 7 , 8 , 9 ], flexible touch displays [ 10 , 11 , 12 , 13 , 14 , 15 ], soft robotics [ 16 , 17 ], and energy harvesting [ 18 , 19 , 20 ]. Recently, flexible pressure sensors, which mimic various biostructures [ 1 , 16 , 21 ] and use a characteristic material [ 1 , 22 , 23 , 24 , 25 , 26 ], have attracted significant research interest.…”