scholarly journals Load Identification for a Cantilever Beam Based on Fiber Bragg Grating Sensors

Sensors ◽  
2017 ◽  
Vol 17 (8) ◽  
pp. 1733 ◽  
Author(s):  
Xuegang Song ◽  
Yuexin Zhang ◽  
Dakai Liang
Keyword(s):  
Fiber Bragg Grating ◽  
Cantilever Beam ◽  
Bragg Grating ◽  
Load Identification ◽  
Fiber Bragg Grating Sensors

STRAIN MEASUREMENT AT CANTILEVER BEAM WITH FIBER BRAGG GRATING SENSORS AND COLLIMATORS AND ITS CORRECTION METHOD

2012 ◽  
Vol 06 ◽  
pp. 576-582
Author(s):  
Seung Min Tak ◽  
Min Kyu Kang ◽  
Dong Jin Park ◽  
Seok Soon Lee
Keyword(s):  
Optical Fiber ◽  
Fiber Bragg Grating ◽  
Cantilever Beam ◽  
Strain Measurement ◽  
Wave Length ◽  
Correction Method ◽  
The Other ◽  
Bragg Grating ◽  
Fiber Bragg Grating Sensors ◽  
Fbg Sensors

Recently, Fiber Bragg Grating(FBG) sensors are being used in various fields. However, it has difficulty to measure at the place where it is not possible to connect fibers each other physically. In this study, using FBG a collimator, we have measured strains with a single optical fiber with many FBG sensors where FBG sensors on one optical fiber line is installed on the beam and the other optical fiber line is connected with an optical interrogator installed at stationary side. The optical fiber lines between an optical fiber line with FBG sensors on the beam and the other optical fiber line on the stationary part are connected by the collimator which makes the use of light's unique characteristic - light travels through space. The experiment showed that the wave length of the light were changed to be linear as strains increased, and the accurate strains were measured by applying the collimator collection factor, which was proposed in this paper.

scholarly journals Load-Identification Method for Flexible Multiple Corrugated Skin Using Spectra Features of FBGs

Aerospace ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 134
Author(s):  
Zhaoyu Zheng ◽  
Jiyun Lu ◽  
Dakai Liang
Keyword(s):  
Structural Health Monitoring ◽  
Fiber Bragg Grating ◽  
Health Monitoring ◽  
Training Data ◽  
Bragg Grating ◽  
Load Identification ◽  
Structural Health ◽  
Fiber Bragg Grating Sensors ◽  
Identification Method ◽  
Load Size

Flexible corrugated skins are ideal structures for morphing wings, and the associated load measurements are of great significance in structural health monitoring. This paper proposes a novel load-identification method for flexible corrugated skins based on improved Fisher discrimination dictionary learning (FDDL). Several fiber Bragg grating sensors are pasted on the skin to monitor the load on multiple corrugated crests. The loads on different crests cause nonuniform strain fields, and these discriminative spectra are recorded and used as training data. The proposed method involves load-positioning and load-size identification. In the load-size-identification stage, a classifier is trained for every corrugated crest. An interleaved block grouping of samples is introduced to enhance the discrimination of dictionaries, and a two-resolution load-size classifier is introduced to improve the performance and resolution of the grouping labels. An adjustable weight is introduced to the FDDL classification scheme to optimize the contribution from different sensors for different load-size classifiers. With the proposed method, the individual loads on eight crests can be identified by two fiber Bragg grating sensors. The positioning accuracy is 100%, and the mean error of the load-size identification is 0.2106 N, which is sufficiently precise for structural health monitoring.

Experimental Mode Shape Identification for a Cantilever Beam Using Optical Fiber Bragg Gratings

2017 ◽  
Author(s):  
Patrick S. Heaney ◽  
Onur Bilgen
Keyword(s):  
Optical Fiber ◽  
Fiber Bragg Grating ◽  
Cantilever Beam ◽  
Mode Shape ◽  
Distributed Parameter ◽  
Bragg Grating ◽  
Single Degree Of Freedom ◽  
Fiber Bragg Grating Sensors ◽  
Single Degree ◽  
Distributed Parameter Model

Parameter estimation of a cantilever beam model typically involves estimating the effective parameters of the system for an assumed mode shape. This shape assumption, which is difficult to verify with traditional single-point sensors, can be validated through the distributed strain measurements available from optical Fiber Bragg Grating sensors. In this paper, the experimental mode shapes of a cantilever beam acquired from Fiber Bragg Grating sensors are compared with the analytical predictions of classical beam theory for the first two bending modes. A single degree of freedom model is also analyzed for the first bending mode and compared to the distributed parameter model and experimental data. It is shown that the distributed parameter model provides a good estimate of the strain profile at the first two natural frequencies, and that the single degree of freedom and distributed parameter models are in close agreement at the first natural frequency.

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