Abstract
In order to solve the problem that the measure precision of coal roof rock strain amount detection using traditional electric sensor is insufficient, a kind of High Sensitive Surface-Pasted Fiber Bragg Grating Strain Sensor based on rock bolting is designed for substitution. Furthermore, a kind of Reference Grating Zero-Strain method based on sensitivity matrix coefficient is proposed for solving FBG strain-temperature cross-sensitivity problem and realizing the better separation relevant to strain and temperature. It is proved that the sensitivity and measurement precision and anti-interference ability of FBG strain sensors are better than traditional electricity class sensors, being able to realize the real-time and online detection for coal roof surrounding rock strain.
Highlights
In order to solve the problem that the measure precision of coal roof rock strain amount detection using traditional electric sensor is insufficient, a kind of High Sensitive Surface-Pasted Fiber Bragg Grating Strain Sensor based on rock bolting is designed for substitution
For the measurement of Fiber Bragg Grating strain sensors applied to bolt supporting used in coal mine with harsh environmental conditions, this paper proposes a specific kind of reference zero-strain grating method based on sensitive coefficients matrix for separation about the strain and temperature
The Fiber Bragg Grating strain sensors that are designed in this paper evaluate the security situation through detecting support anchors roof rock stress effect
Summary
Sensing principle of fiber grating optical wavelength signal is shown in Figure 1: when a length of broadband light is incident to fiber grating, an optical wavelength that satisfied the Bragg condition will be reflected back to the grating and the light that does not satisfy the Bragg condition will be transmitted. Reflected or transmitted wavelength spectrum depends primarily on the period exchange amounts ΔΛ of the fiber grating and the effective refractive index of the fiber grating neff based on Fiber Optic Grating coupled-mode theory. The effective refractive index neff and the grating period variations ΔΛ will be affected by environmental factors (strain, temperature, etc.). When the Fiber Bragg Grating has been acted by stress and temperature and other external factors, due to the elastic action it will result in the transformation about the effective refractive index neff and the grating period Λ, while the transformations related to these parameters will result in change in the reflection wavelength of the grating. Wherein ε represents strain variation in the Fiber Bragg Grating; Pe represents the fiber effective elastic optic coefficient; ΔT represents the temperature transformation. Formula (2) shows that it needed to analyze its strain sensing properties and temperature sensing performances when the Fiber Bragg Grating strain sensors are used to measure in the real environment
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
