Geng Shuwei, Yu Youlong Fiber Bragg Grating time multiplexed sensor system.This is supported by the National Key Scientific Instrument Development Projects, No. 2013YQ470765. DEVE-1201 produced by Austrian DEWETRON Company is adopted as data acquisition system for strain gauge data, and the strain gauges with resistance 120 Ω are pasted in-line.Īs shown in Fig. 4, The FBG sensor and the strain gauge are pasted 358 mm away from one side of the equi-intensity cantilever beam, where added weights, the cantilever is 59 mm wide and 3.7 mm thick the position of the cantilever is fixed, and the FBG sensor and strain gauge are connected to the data acquisition instrument at room temperature, 1000 g, 2000 g, 3000 g and 4000 g weights are added sequentially, thus the cantilever bends down to produce strain the signal emitted by the broadband light source which is internal integrated in the FBG demodulation, is transferred to the sensor through FBG, and the reflection light is transmitted into the FBG demodulation, meanwhile, the wavelength is displayed on the computer. SM125 FBG demodulation produced by American Micron Optics Company is used in the experiment, whose sensitivity is 0.1 pm and sampling frequency is 2 Hz, and the center wavelength of FBG sensor without strain is 1531.0218 nm at room temperature. The results indicate that FBG strain measurement method is feasible and accurate. To verify the feasibility and accuracy of the FBG strain measurement, equi-intensity cantilever beam experiments are designed and performed in this paper, and two methods using a FBG sensor and a strain gauge are adopted respectively, after data acquisition and processing, the testing data are compared with the theoretical values respectively. What’s more, one fiber can be made into dozens of sensors to constitute a distributed sensing system theoretically. With the characters of explosion proof, immunity to electrical interference, radiation and corrosion, thermostability, small size, light weight and flexibility, FBG can be used under harsh circumstances repeatedly. In recent years, as a new optical passive device, FBG sensors have been applied in the fiber sensing area widely. However, since the stain gauges can be easily affected by circumstance factors, such as electromagnetic fields, temperature, moisture and chemical corrosion, its application is limited to a certain extent. By tests and calculations, the stains at the measured points are obtained. In the measurements, strain gauges are pasted on the surface of work pieces, and the resistance of the strain gauges will change correspondingly with the strain produced by loading. In engineering, a traditional way to obtain strain data is by strain gauge measurements.
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