A novel OFDR-based distributed optical fiber sensing tape: design, optimization, calibration and application

Abstract

The significance of implementing structural health monitoring (SHM) system for civil engineering, especially infrastructure engineering, has been recognized. Distributed optical fiber sensor (DOFS) based on optical frequency domain reflectometer (OFDR) offers an attractive technique for in situ strain measurement due to its high resolution and high precision. However, a main challenge that naturally arises is how to guarantee sensors survival in harsh construction and service environments. In this paper, a new, but simple, packaging technique is proposed to solve this issue. The novel sensing tape is fabricated by embedding DOFS into two fiberglass tapes and its strain transfer mechanism is analyzed in detail to provide scientific criteria for the choice of the material parameters. Then, a calibration test is carried out to evaluate the performance of the sensing tape in distributed strain measurement. Finally, the tape sensor is applied to the surface strain monitoring of the reinforced concrete (RC) beam tested in three-point bending. Experimental results verify that the sensing tape works well on concrete materials and the strain measured has the capability to reveal and localize cracks. Both analytical and experimental results demonstrate that the proposed packaging technique is feasible and effective.