Research on Multi-Point large strain measurement sensors based on flexible thin Films and fiber Bragg Gratings

To achieve highly sensitive distributed measurement of large strains, this paper proposes a surface-attached FBG array sensor based on a flexible PDMS/SiO 2 substrate. The sensor structure is designed, and a finite element model of the flexible thin-film substrate and the S-shaped grating array is established to analyze the strain distribution under a 20 % tensile condition. Theoretical simulation results indicate that the S-shaped path can deform together with the flexible substrate and enhance the optical fiber adaptability to tensile deformation through path extension. Sensor samples with different substrate materials were fabricated, and strain and temperature measurement experiments were conducted. Experimental results show that the sensor can achieve multi-point large strain measurement in the range of 0 to 13 %, with a sensitivity of 527 pm/1 %. Temperature can be effectively measured within the range of 25 °C to 160 °C. This study demonstrates that the sensor holds significant application potential in the field of multi-point distributed large strain measurement.