Long-term mechanical properties of smart cable based on FBG desensitized encapsulation sensors

Abstract

In order to ensure the testing range and long-term reliability of the fiber Bragg grating (FBG) used for the smart cable, a smart cable embedded with FBG strain sensors based on the desensitized encapsulation structure was designed. For a smart cable specimen, the fatigue loading experiments with the cycle from 100 thousands to 2 million and 0.95 times nominal breaking cable force (P _b) were carried out, which tested the long-serving effects of the smart cable. The test results of the static tension loading and unloading during the stepwise fatigue cycle process showed that the encapsulated FBG strain sensors had the good linearity and repeatability. Also all sensors survived after 2 million times fatigue cycle. 0.95P _b static tension test showed that the encapsulated FBG strain sensors embedded inside the cable reached 4.5% testing accuracy in the 0.86P _b working range. After 0.95P _b static tension test, the dissection test was carried out by breaking the force tension. The results showed that the appearances of the encapsulated sensors were good, and the design structures were not changed and damaged.

Keywords

Smart cable / fatigue experiment / fiber Bragg grating / force monitoring / bridge engineering

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