Biaxial 3D-Printed Inclinometer Based on Fiber Bragg Grating Technology

Abstract

Fiber Bragg Grating (FBG)-based inclinometer has been developed for field use, designed to incorporate biaxial 3-dimensional (3D) printed tilt sensors (in which four FBGs were used). The inclinometer was characterized by examining its response to a wide range of tilts, over the range from 0° to 90°, towards the inclination axes. An excellent linear correlation between the wavelength shifts and the inclination angle (up to the 90° used) was obtained, showing an average sensitivity of 0.01 nm per degree of inclination angle, for each of the FBGs used. In addition to the four FBGs that form the basis of the inclination measurement, a further FBG was included in the design to allow compensation for any temperature changes experienced during the measurements. The device was calibrated over the range from -25°C to 80°C (corresponding to the extremes of cold and hot weather conditions likely to be experienced in-the-field), and a sensitivity to temperature change of 0.011nm/°C was achieved, allowing an effective temperature correction to be applied. The data obtained from a full characterization of the performance of the sensor system, carried out in a stable, controlled environment, indicate that this inclinometer yields good sensitivity, making it highly applicable for use in monitoring rapid ground movements and deformations with its compact design allowing its wide use.

Application of Optical Fiber Sensing Technology in Permeability Test of Three-Dimensional Physical Model of Medium and Long-Distance Diversion Tunnel

“…Fiber Bragg grating sensors are mainly laid on the surface of steel pipes to make FBG settlement pipes, and multiple FBG settlement pipes are combined through sleeves to connect long-distance FBG settlement pipes. At the same time, the installation scheme is designed in detail, and a long-distance FBG settlement pipe monitoring system is built, which has been successfully applied to the settlement monitoring of Shanghai Metro Line 8 [8]. Wang et al installed optical fiber displacement sensors on the tunnel rock wall to monitor the stress of surrounding rock during tunnel construction [9].…”

Optical fiber Bragg grating-based pressure sensor for soil monitoring applications

“…This provides for cross-sensing applications such as strain and temperature measurement in a single sensor network 18 , 19 . Many researchers have already demonstrated FBG sensors to measure strain, 20 , 21 temperature, 22 inclination, 23 , 24 humidity, 25 and pressure, 26 – 28 indicating their potential as a sensor.…”

Surface-Mounted Tilt Sensor Using Fiber Bragg Grating Technology for Engineered Slope Monitoring With Temperature Compensation

“…Although several devices possess better sensitivity values, their design is bulky and comprises complex mechanical parts, which render their sensor unsuitable for field applications. There are no reports regarding the implementation of such tilt sensors in real-field applications [19], [20], [24] except in this demonstration.…”

“…Various optical fiber-based sensors have been proposed in the past in geotechnical sectors and structural health monitoring, such as Michelson interferometer sensors [11], Fabry-Perot strain sensors [12], Brillouin's scatter-based distributed sensors [13], [14], and fiber Bragg grating (FBG) sensors [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28]. FBG-based sensors are among the best options due to their multiplexing capabilities and the utilization of long fiber optics cables, which are crucial in monitoring high-risk slopes remotely [29].…”