Distributed strain sensing cable based on ultra-weak fiber grating

Aiming at improving the performance of distributed sensing fiber, a distributed strain sensing optical cable based on ultra-weak fiber gratings is proposed. The optical cable is prepared by pretreating an ultra-weak fiber grating array with a pitch of 0.2 m, compounding it with glass fiber to make an FRP sensing fiber with a diameter of 1.0 mm, and then twisting with a steel cable and extruding the sheath. The multilayer structure strain transfer model of steel cable-FRP-optical fiber is established, and the temperature characteristics of the optical cable were tested by the water bath method, the tensile test of the optical cable was carried out by the tensile machine. The results show that the temperature sensitivity of the optical cable is 23.8 pm/°C, the strain sensitivity is 1.72 pm/N, there is no "strain dead zone" during strain tension, and the strain transfer effect is good, which provides a potential solution for high-resolution distributed strain sensing.