Strain-insensitive fiber Bragg grating composite structure for wide-range temperature sensing

This paper reports on the design, fabrication, and temperature strain sensing performance of a fiber Bragg grating composite structure for surface mounted temperature measurements over a wide temperature range, with highly reduced strain cross-sensitivity. The fiber Bragg grating sensor is encapsulated in a polyimide tube filled with epoxy resin, forming an arc-shaped cavity. This assembly is then placed between two layers of glass fiber prepreg with a flexible pad in between and cured into shape. Experimental results, supported by finite element simulations, demonstrate an enhanced temperature sensitivity is 26.3 pm/ºC over a wide temperature range of -30℃ to 70℃, and high strain transfer isolation of about 99.65%. Conflict of Interest Statement The authors declare no conflicts of interest.