Fiber Bragg Grating Sensors for Pile Jacking Monitoring in Clay Soil

The small deformation of the model pile in a pile jacking test makes its accurate measurement very difficult. Based on the installation method of clamping at both ends, a sensitized miniature fiber Bragg grating (FBG) strain sensor was developed to measure the pile strain of small-size model piles. This study investigated the working principle of the sensitized miniature FBG sensor and analyzed the strain transfer characteristics of the sensor by calibration test. The lateral resistance and the earth plug resistance of the model pile were measured accurately by the grooves embedded in the outer tube of the double-wall opening model pile and the sensors directly pasted on the surface of the inner tube. The results of this study show that the sensitized miniature FBG strain sensor has the advantages of high sensitivity, strong interference resistance, and high test accuracy. The FBG strain sensor was completely fixed on the pile by clamping supports at both ends, and the strain measured using the FBG strain sensor was found to be consistent with the pile deformation.

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High-Sensitivity Fiber Bragg Grating Strain Sensor Based on Singlemode-Multimode-Singlemode Tapered Structure

Laser & Optoelectronics Progress ◽

10.3788/lop56.132802 ◽

2019 ◽

Vol 56 (13) ◽

pp. 132802

Author(s):

王洪海 Honghai Wang ◽

彭思敏 Simin Peng ◽

桂鑫 Xin Gui ◽

王昌佳 Changjia Wang ◽

李政颖 Zhengying Li

Keyword(s):

Fiber Bragg Grating ◽

Strain Sensor ◽

High Sensitivity ◽

Bragg Grating

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Development of an Optical Fiber Sensor with a D-shaped Fiber Bragg Grating Integrated in a Loop-mirror Optical Fiber Laser as a High Sensitivity Refractometer

Communications in Physics ◽

10.15625/0868-3166/16014 ◽

2021 ◽

Vol 32 ◽

Author(s):

Binh Pham Thanh ◽

Thuy Van Nguyen ◽

Van Hoi Pham ◽

Huy Bui ◽

Thi Hong Cam Hoang ◽

...

Keyword(s):

Refractive Index ◽

Optical Fiber ◽

Fiber Laser ◽

Fiber Bragg Grating ◽

Limit Of Detection ◽

Optical Fiber Sensor ◽

High Sensitivity ◽

Optical Signal ◽

Bragg Grating ◽

Loop Mirror

In this paper, we report a new type of refractometer based on a D-shaped fiber Bragg grating (FBG) integrated in a loop-mirror optical fiber laser. This proposed sensor is used in wavelength interrogation method, in which the D-shaped FBG is applied as a refractive index (RI) sensing probe and a mirror to select mode of laser. The D-shaped FBG is prepared by the removal of a portion of the fiber cladding covering the FBG by means of side-polishing technique. The D-shaped FBG sensing probe integrated in a loop-mirror optical fiber laser with saturated pump technique, the characteristics of sensing signals have been improved to obtain stable intensity, narrower bandwidth and higher optical signal-to-noise ratio compare to normal reflection configuration. The limit of detection (LOD) of this sensor can be achieved to 2.95 x 10-4 RIU in the refractive index (RI) range of 1.42-1.44. Accordingly, we believe that the proposed refractometer has a huge potential for applications in biochemical-sensing technique.

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Early-Age Autogenous Shrinkage of High-Performance Concrete Columns by Embedded Fiber Bragg-Grating Sensor

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.419-420.1 ◽

2009 ◽

Vol 419-420 ◽

pp. 1-4 ◽

Cited By ~ 2

Author(s):

Ying Wei Yun ◽

Ii Young Jang ◽

Seong Kyum Kim ◽

Seung Min Park

Keyword(s):

Fiber Bragg Grating ◽

High Performance ◽

High Performance Concrete ◽

Construction Material ◽

Autogenous Shrinkage ◽

Strain Sensor ◽

Bragg Grating ◽

Early Age ◽

Long Time ◽

Sensor Temperature

High-performance concrete (HPC) as a promising construction material has been widely used in infrastructures and high-rise buildings etc. However, its pretty high autogenous shrinkage (AS) especially in its early age becomes one of the key problems endangering long-time durability of HPC structures. This paper carried out the early age AS research of large scaled HPC column specimens by embedded Fiber Bragg-Grating (FBG) strain sensor. Temperature compensation for FBG strain sensor by thermocouple was also attempted in this paper, and the results were reasonable and acceptable comparing with the result compensated by FBG temperature sensor. Reinforcement influence, size effect and temperature effect on HPC AS were also analyzed respectively in this paper.

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