Damage detection based on strain transmissibility for beam structure by using distributed fiber optics

Structural damage identification is a coral and challenging research topic. Research mainly focuses on identification and detection of linear damage in structures by using modal parameters such as change of natural frequency, frequency response function, mode shape, etc. Transmissibility is conventionally defined as the spectra ratio of two measurement points, which has been utilized for damage identification as a powerful damage indicator. In this paper, strain transmissibility, defined as ratio of strain response spectra, is proposed as a new damage indicator. In order to achieve more precise sensing information, distributed fiber optics has been applied to damage detection on a beam structure, which adds new capability of sensing with its combination of high spatial density sensing and dynamic acquisition over a single optical fiber sensor. A numerical simulation has been conducted to investigate the feasibility of strain transmissibility for damage detection which has revealed a better performance compared to traditional transmissibility. The applicability of the proposed method has been confirmed by applying distributed fiber optics on a clamped-clamped beam. Both simulation and experiment validate the effectiveness of damage detection approach based on strain transmissibility by using distributed fiber optics.