Local high edge observation for the bonding line monitoring of a complex composite beam

2020 ◽  
pp. 095440622093219
Author(s):  
Monica Ciminello ◽  
Bernardino Galasso ◽  
Gianvito Apuleo ◽  
Shay Shoam ◽  
Antonio Concilio
Keyword(s):  
Strain Field ◽  
Composite Beam ◽  
Composite Structures ◽  
Longitudinal Strain ◽  
Fiber Optic ◽  
Signal To Noise Ratio ◽  
Fiber Optic Sensors ◽  
Signal To Noise ◽  
Mechanical Loads ◽  
Spatial Domains

The most part of defects in composite structures carrying attached subelements is the disbond at the interface, as the skin/stringer sections. This is sometimes due to a nonoptimal manufacturing process or sometimes due to accidental object impacts during service. It has been verified that structural discontinuities within an elastic medium under mechanical loads can cause analogous discontinuities within the strain field. Starting from this analysis, the present work investigates the effect of artificially induced kissing bond areas just at the in the skin–stiffener interface of an aeronautical complex composite beam. This research uses longitudinal strain values, acquired at the locations where distributed fiber optic sensors are installed. The applied methodology uses different strain-based features providing local high edge observation both in time and spatial domains. Their autocorrelations are, in the end, computed to improve signal-to-noise ratio. The local high edge observation algorithm is proposed that proves its capability to monitor disbond being at the same time load and baseline independent.

Component Selection for Fiber-Optic Fluorometry

1990 ◽  
Vol 44 (1) ◽  
pp. 117-122 ◽  
Author(s):  
Richard B. Thompson ◽  
Michael Levine ◽  
Lynne Kondracki
Keyword(s):  
Systematic Study ◽  
Fiber Optic ◽  
Signal To Noise Ratio ◽  
Fiber Optic Sensors ◽  
Fluorescence Sensor ◽  
Measured Signal ◽  
Optimized Design ◽  
Signal To Noise ◽  
Component Selection ◽  
Selection For

A wide variety of fiber-optic sensors based on fluorescence have been developed for important applications in the last few years. Unfortunately, no systematic study describing an optimized design has appeared. A fiber-optic fluorescence sensor testbed was constructed, and different optical designs and components were compared for sensitivity in detecting fluorescence. Different beamsplitters, launching objectives, filters, detectors, and configurations were evaluated on the basis of their measured signal-to-noise ratio in detecting 100 picomolar fluorescein. Sources of noise and background were identified, and generally applicable means for minimizing them are described.

The Effect of Length and Diameter on the Signal-to-Noise Ratio of Evanescent Field Absorption Fiber-Optic Sensors

1992 ◽  
Vol 46 (7) ◽  
pp. 1129-1133 ◽  
Author(s):  
T. B. Colin ◽  
K.-H. Yang ◽  
M. A. Arnold ◽  
Gary W. Small ◽  
W. C. Stwalley
Keyword(s):  
Near Infrared ◽  
Fiber Optic ◽  
Signal To Noise Ratio ◽  
Fiber Optic Sensors ◽  
Evanescent Field ◽  
Infrared Sensor ◽  
Signal To Noise ◽  
Optimal Length ◽  
Sensor Applications ◽  
Field Sensor

This paper discusses the theoretical and experimental implications of changing the length and diameter of the evanescent field sensing region of an evanescent field sensor. Particular emphasis is placed on optimizing the intensity of the evanescent field for near-infrared sensor applications. Both theoretical and experimental results show that an optimal length and diameter must be determined experimentally for each analyte system.

scholarly journals Technical Note: Determining regions of interest for CCD camera-based fiber optic luminescence dosimetry by examining signal-to-noise ratio

2011 ◽  
Vol 38 (3) ◽  
pp. 1374-1377 ◽  
Author(s):  
David M. Klein ◽  
Francois Therriault-Proulx ◽  
Louis Archambault ◽  
Tina M. Briere ◽  
Luc Beaulieu ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Signal To Noise Ratio ◽  
Ccd Camera ◽  
Technical Note ◽  
Regions Of Interest ◽  
Signal To Noise ◽  
Luminescence Dosimetry ◽  
Noise Ratio

Strain Field Identification of an Aluminum Plate by using Distributed Fiber-Optic Sensors

2017 ◽  
Author(s):  
HIDEHARU OGINO ◽  
HIDEAKI MURAYAMA ◽  
FUMIYA FUJIMORI ◽  
KAZURO KAGEYAMA ◽  
DAICHI WADA ◽  
...  
Keyword(s):  
Strain Field ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Aluminum Plate ◽  
Field Identification

scholarly journals Local and Global Approaches for Damage Detection in Composite Structures by Fiber Optic Sensors

2018 ◽  
Author(s):  
Alfredo Guemes ◽  
Antonio Fernandez- Lopez ◽  
Patricia F. Diaz-Maroto ◽  
Angel Lozano ◽  
Julián Sierra-Pérez
Keyword(s):  
Damage Detection ◽  
Composite Structures ◽  
Fiber Optic ◽  
A Priori ◽  
Fiber Optic Sensors ◽  
Network Density ◽  
Strain Measurements ◽  
Damage Location ◽  
Local Technique ◽  
External Loads

Fiber optic sensors cannot measure damage; for getting information about damage from strain measurements, additional strategies are needed, and several alternatives have been proposed. This paper discuss two independent concepts: the first one is based on detecting the new strains appearing around a damage spot; the structure does not need to be under loads; the technique is very robust, damage detectability is high, but it requires sensors to be located very close to the damage, so it is a local technique. The second approach offers a wider coverage of the structure, it is based on identifying the changes caused by the damage on the strains field in the whole structure for similar external loads. Damage location does not need to be known a priori, detectability is dependent upon the sensors network density, damage size and the external loads. Examples of application to real structures are given.

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