Performance Characteristics of Fiber-Optic Strain Sensors as Compared With Electrical Resistance and Vibrating Wire Strain Gauges

摘要

This paper presented experimental results of fiber-optic sensor performance in terms of its accuracy, repeatability, and reproducibility. Strain sensors were embedded in concrete specimens, which were then subjected to the same known static and dynamic load, and their responses were compared to each other on the same basis. In addition to evaluating the response due to load, the measurements due to concrete drying shrinkage were also evaluated. According to the experimental test results, the fiber-optic strain sensor (FOS) showed an average error of 2.7 με, as compared with average errors of 5.7 and 5.6 με for an electrical resistance strain gauge and a vibrating wire strain gauge (VWSG), respectively. In addition, the repeatability of the FOS in terms of coefficient of variation (COV) was 7.5 % as compared with COVs of 4.4,5.6, and 9.6 % for three different electrical resistance strain gauges and the reproducibility of the FOS in terms of COV was 9.8 % as compared with COVs of 5.4,5.7, and 10.1 % for three different electrical resistance gauges. When compared with the strains measured by a calibrated LVDT in a concrete drying shrinkage test where the strains varied from 0 to around 250 με, the FOS showed an average difference of 30.37 με, whereas the VWSG showed an average difference of 34.04 με. However, these difference were statistically insignificant at 95 % confidence level. Based on these results, it can be concluded that the FOS is found to have similar accuracy, repeatability, and reproducibility as compared to electrical resistance and VWSG.