A comparative analysis of FBG and low-coherence fiber-optic sensors for SHM of composite structures

2013 ◽  
Author(s):  
Zoran Djinovic ◽  
Milos Tomic ◽  
Marijana Stojkovic
Keyword(s):  
Comparative Analysis ◽  
Composite Structures ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Low Coherence

scholarly journals Digital phase demodulation for low-coherence interferometry-based fiber-optic sensors

2018 ◽  
Vol 411 ◽  
pp. 27-32 ◽  
Author(s):  
Y. Liu ◽  
R. Strum ◽  
D. Stiles ◽  
C. Long ◽  
A. Rakhman ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Low Coherence ◽  
Digital Phase ◽  
Low Coherence Interferometry ◽  
Phase Demodulation

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.

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.

scholarly journals Fatigue Behavior of Smart Composites with Distributed Fiber Optic Sensors for Offshore Applications

2021 ◽  
Vol 6 (1) ◽  
pp. 2
Author(s):  
Monssef Drissi-Habti ◽  
Venkadesh Raman
Keyword(s):  
Composite Structures ◽  
Large Scale ◽  
Fiber Optic ◽  
Fatigue Behavior ◽  
Turbine Blades ◽  
Mechanical Tests ◽  
Fiber Optic Sensors ◽  
Fatigue Tests ◽  
Offshore Wind ◽  
Smart Composites

Continuous inspection of critical zones is essential to monitor the state of strain within offshore wind blades, thus, enabling appropriate actions to be taken when needed to avoid heavy maintenance. Wind-turbine blades contain various substructures made of composites, sandwich panel, and bond-joined parts that need reliable Structural Health Monitoring (SHM) techniques. Embedded, distributed Fiber-Optic Sensors (FOS) are one of the most promising techniques that are commonly used for large-scale smart composite structures. They are chosen as monitoring systems for their small size, being noise-free, and low electrical risk characteristics. In recent works, we have shown that embedded FOSs can be positioned linearly and/or in whatever position with the scope of providing pieces of information about actual strain in specific locations. However, linear positioning of distributed FOS fails to provide all strain parameters, whereas sinusoidal sensor positioning has been shown to overcome this issue. This method can provide multiparameter strains over the whole area when the sensor is embedded. Nevertheless, and beyond what a sensor can offer as valuable information, the fact remains that it is a “flaw” from the perspective of mechanics and materials. In this article and through some mechanical tests on smart composites, evidence was given that the presence of embedded FOS influences the mechanical behavior of smart composites, whether for quasi-static or fatigue tests, under 3-point bending. Some issues directly related to the fiber-architecture have to be solved.

Optimization of coating diameter of fiber optic sensors embedded in composite structures under arbitrary loading conditions

2015 ◽  
Vol 24 (11) ◽  
pp. 115003 ◽  
Author(s):  
Nicolas Lammens ◽  
Geert Luyckx ◽  
Eli Voet ◽  
Wim van Paepegem ◽  
Joris Degrieck
Keyword(s):  
Composite Structures ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Loading Conditions ◽  
Arbitrary Loading

Fizeau Receiving Interferometer with 2-D CCD Matrix for Low Coherence Interferometric Fiber Optic Sensors

2008 ◽  
Author(s):  
Miloš C. Tomić ◽  
Zoran V. Djinović ◽  
Niklaus Ursus Wetter ◽  
Jaime Frejlich
Keyword(s):  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Low Coherence ◽  
Ccd Matrix
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