Strain sensor based on coaxial cable Bragg grating with gradient cross section

The strain sensor based on coaxial cable Bragg grating (CCBG) is an effective tool for precise structural health monitoring of large-scale infrastructure. Meanwhile, expanding the monitoring range, reducing the tensile slip and improve the reusability were still needed, so a design method for strain sensor based on gradient cross section CCBG (GC-CCBG) with low elastic modulus insulating layer was proposed in this paper. The gradient cross section of CCBG was employed to achieve a more flexible form of impedance discontinuity, so as to easily adjust the band gap characteristics. The spline interpolation curve was used to describe the shape of the gradient cross section. Based on cubic spline interpolation, a typical GC-CCBG sensor was designed as a numerical example. The insulating layer with gradient cross section of the prototype was fabricated by 3D printing tech-nology. The feasibility of the proposed method for strain sensor was verified through simulation and experiment. The influence of the interpolation knots on sensing characteristics was also discussed.

Automated summary

A design method for a strain sensor based on gradient cross section coaxial cable Bragg grating (GC-CCBG) with a low elastic modulus insulating layer was proposed in this paper to achieve a wider monitoring range, reduced tensile slip, and improved reusability. The gradient cross section of the CCBG was employed to easily adjust the band gap characteristics. A numerical example of a GC-CCBG sensor was designed using cubic spline interpolation, and a prototype with a gradient cross-section insulating layer was fabricated using 3D printing technology. Simulation and experiment were conducted to verify the feasibility of the proposed method for the strain sensor, and the influence of interpolation knots on sensing characteristics was discussed.