Study on the Mechanism of Static Comparison between Vibrating String Strain Gauge and Fiber Grating Strain Gauge for Bridge Structure Monitoring

Abstract

The key component commonly used in strain monitoring is the strain sensor (strain gauge), which is usually embedded inside the measured object or installed on its surface to monitor the changes of corresponding variables for a long time. Therefore, the reliability, accuracy, consistency and stability of the strain sensor are important guarantees for the accurate measurement of strain. In order to monitor bridge changes more accurately, two strain sensors with a wide range of applications (i.e. vibration string strain sensor and fiber grating strain sensor) were selected for comparative analysis of the calibration model in the laboratory. We’ll use national standard of 6061 aluminum alloy cylindrical bar and fix two strain sensors separately in the symmetric position. In order to eliminate the detection error caused by the current sensor detection when the metering clamping device and the strain sensor are under stress, 0-100kn compression test was conducted on the bar by using the superposition force standard machine. The device collects data of the two sensors, conducts data regression analysis, obtains the new model and hence conducts data analysis and comparison. The results show that the accuracy of the model is much higher than that of the strain sensor. The results of this study provide technical support for the development of real-time bridge detection technology and the realization of rapid calibration and detection of strain monitoring sensors used in the transportation industry before installation.