Techno Press
Techno Press

Smart Structures and Systems   Volume 18, Number 6, December 2016, pages 1203-1215
DOI: http://dx.doi.org/10.12989/sss.2016.18.6.1203
 
Fatigue characteristics of distributed sensing cables under low cycle elongation
Dan Zhang, Jiacheng Wang, Bo li and Bin Shi

 
Abstract     [Full Text]
    When strain sensing cables are under long-term stress and cyclic loading, creep may occur in the jacket material and each layer of the cable structure may slide relative to other layers, causing fatigue in the cables. This study proposes a device for testing the fatigue characteristics of three types of cables operating under different conditions to establish a decay model for observing the patterns of strain decay. The fatigue characteristics of cables encased in polyurethane (PU), GFRP-reinforced, and wire rope-reinforced jackets were compared. The findings are outlined as follows. The cable strain decayed exponentially, and the decay process involved quick decay, slow decay, and stabilization stages. Moreover, the strain decay increased with the initial strain and tensile frequency. The shorter the unstrained period was, the more similar the initial strain levels of the strain decay curves were to the stabilized strain levels of the first cyclic elongation. As the unstrained period increased, the initial strain levels of the strain decay curves approached those of the first cyclic elongation. The tested sensing cables differed in the amount and rate of strain decay. The wire rope-reinforced cable exhibited the smallest amount and rate of decay, whereas the GFRP-reinforced cable demonstrated the largest.
 
Key Words
    distributed fiber optic sensing; strain sensing cable; fatigue; strain decay; low cycle elongation
 
Address
Dan Zhang, Jiacheng Wang, Bo li and Bin Shi: School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, P.R. China
 

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