Hybrid guided wave based SHM system for composite structures for impact and delamination detection combining fiber Bragg grating sensing and piezoelectric patches

2018 ◽  
Author(s):  
Ernesto Monaco ◽  
Natalino Daniele Boffa ◽  
Leandro Maio ◽  
Fabrizio Ricci ◽  
Edgar Mendoza ◽  
...  
Keyword(s):  
Fiber Bragg Grating ◽  
Composite Structures ◽  
Guided Wave ◽  
Bragg Grating ◽  
Delamination Detection

scholarly journals Guided wave-based system for real-time cure monitoring of composites using piezoelectric discs and phase-shifted fiber Bragg gratings

2018 ◽  
Vol 53 (7) ◽  
pp. 969-979 ◽  
Author(s):  
Tyler B Hudson ◽  
Nicolas Auwaijan ◽  
Fuh-Gwo Yuan
Keyword(s):  
Physical Properties ◽  
Fiber Bragg Grating ◽  
Real Time ◽  
Fiber Optic ◽  
Guided Wave ◽  
Fiber Optic Sensor ◽  
State Transitions ◽  
Bragg Grating ◽  
Cure Cycle ◽  
Cure Monitoring

A real-time, in-process cure monitoring system employing a guided wave-based concept for carbon fiber reinforced polymer composites was developed. The system included a single piezoelectric disc that was bonded to the surface of the composite for excitation, and an embedded phase-shifted fiber Bragg grating for sensing. The phase-shifted fiber Bragg grating almost simultaneously measured both quasi-static strain and the ultrasonic guided wave-based signals throughout the cure cycle. A traditional FBG was also used as a base for evaluating the high sensitivity of the phase-shifted fiber Bragg grating sensor. Composite physical properties (degree of cure and glass transition temperature) were correlated to the amplitude and time of arrival of the guided wave-based measurements during the cure cycle. In addition, key state transitions (gelation and vitrification) were identified from the experimental data. The physical properties and state transitions were validated using cure process modeling software (e.g. RAVEN®). This system demonstrated the capability of using an embedded phase-shifted fiber Bragg grating to sense a wide bandwidth of signals during cure. The distinct advantages of a fiber optic-based system include multiplexing of multiple gratings along a single optical fiber, small size compared to piezoelectric sensors, ability to embed or surface mount, utilization in harsh environments, electrically passive operation, and electromagnetic interference (EMI) immunity. The embedded phase-shifted fiber Bragg grating fiber optic sensor can monitor the entire life-cycle of the composite structure from curing, post-cure/assembly, and in-service creating “smart structures”.

Health Monitoring of Composite Material Using Fiber Bragg Grating

2012 ◽  
Author(s):  
S. J. Fattahi ◽  
D. Necsulescu
Keyword(s):  
Composite Materials ◽  
Fiber Bragg Grating ◽  
Health Monitoring ◽  
Composite Structures ◽  
Rapid Development ◽  
Bragg Grating ◽  
Stress And Strain ◽  
Layered Composites ◽  
Large Size ◽  
Applied Forces

Recently, the use of composite materials in different applications like aircrafts, wind turbines and towers has developed rapidly. This rapid development of large size composite structures is, though, not without its problems, particularly in case of difference in lamination when using various materials. Health monitoring and delaminating preventive maintenance are important issues when using composite materials. The use of smart structures enables real-time monitoring of the composite materials and permits applications using sensors to appropriately arrive to a desired state. This paper presents an optimal, inexpensive and continuous laminated sensor based monitoring in composites using Fiber Bragg Grating (FBG). This paper investigates layered composites and FEM based on the static and dynamic equations and the mechanical behavior with respect to stress and strain. Delaminating criteria of a composite cantilever beam can be analyzed based on wavelength shifting relations of FBG and in the resulting reflected spectrum caused by applied forces or displacements.

Fiber Bragg grating based displacement sensors: state of the art and trends

Sensor Review ◽  
2019 ◽  
Vol 39 (1) ◽  
pp. 87-98 ◽  
Author(s):  
Wenlong Liu ◽  
Yongxing Guo ◽  
Li Xiong ◽  
Yi Kuang
Keyword(s):  
Fiber Bragg Grating ◽  
Composite Structures ◽  
Structure Design ◽  
Bragg Grating ◽  
Content Type ◽  
Displacement Sensors ◽  
Special Fibers ◽  
Beam Type ◽  
Information Detection ◽  
Wavelength Detection

Purpose The purpose of this paper is to present the latest sensing structure designs and principles of information detection of fiber Bragg grating (FBG) displacement sensors. Research advance and the future work in this field have been described, with the background that displacement and deformation measurements are universal and crucial for structural health monitoring. Design/methodology/approach This paper analyzes and summarizes the existing FBG displacement sensing technologies from two aspects principle of information detection (wavelength detection, spectral bandwidth detection, light intensity detection, among others) and principle of the sensing elastomer structure design (cantilever beam type, spring type, elastic ring type and other composite structures). Findings The current research on developing FBG displacement sensors is mainly focused on the sensing method, the construction and design of the elastic structure and the design of new information detection method. The authors hypothesize that the following research trends will be strengthened in future: temperature compensation technology for FBG displacement sensors based on wavelength detection; a study of more diverse elastic structures; and fiber gratings manufactured with special fibers will greatly improve the performance of sensors. Originality/value The latest sensing structure designs and principles of information detection of FBG displacement sensors have been proposed, which could provide important reference for research group.

Fiber Bragg grating spectral features for structural health monitoring of composite structures

2014 ◽  
Author(s):  
Sean Webb ◽  
Kara Peters ◽  
Mohammed Zikry ◽  
Nikola Stan ◽  
Spencer Chadderdon ◽  
...  
Keyword(s):  
Structural Health Monitoring ◽  
Fiber Bragg Grating ◽  
Health Monitoring ◽  
Composite Structures ◽  
Bragg Grating ◽  
Spectral Features ◽  
Structural Health

Interlayer Strain Monitoring of Hybrid Composites With Carbon Nanofiber Paper Using Fiber Bragg Grating Sensors

2006 ◽  
Author(s):  
Xuefeng Zhao ◽  
Jihua Gou ◽  
Gangbing Song
Keyword(s):  
Fiber Bragg Grating ◽  
Composite Laminates ◽  
Composite Structures ◽  
Carbon Nanofiber ◽  
Hybrid Composites ◽  
Fiber Composite ◽  
Low Cost ◽  
Bragg Grating ◽  
Fbg Sensors ◽  
Vartm Process

Graphite/epoxy prepregs are typically used to manufacture aerospace composite structures through autoclave processing. However, the vacuum-assisted resin transfer molding (VARTM) process has recently received increasing attention as a low-cost method to fabricate quality aerospace structures. In this study, carbon nanofiber paper was integrated into composite laminates using the VARTM process. The carbon nanofiber paper has a porous structure with highly entangled carbon nanofibers. The carbon nanofiber paper can be employed as an inter-layer and surface layer to enhance the damping properties of the nanocomposites. To study the integration performance of nanocomposites with nanofiber paper layer, Fiber Bragg Grating (FBG) sensors were embedded into interlayers of the composite. Two kinds of nanocomposite specimens with FBG sensors were designed and fabricated to study the strain distribution characteristics among different layers. The interlayer strains in under static loads were measured simultaneously to test whether nanofiber paper can be successfully integrated into glass fiber composite. The test results show the two different layers of nanofiber paper and glassfiber are fully integrated to the composite. In addition, a novel tensile test of carbon nanofiber paper-enabled nanocomposites using FBG sensors was conducted to demonstrate the bonding strength between the nanofiber paper layer and the glassfiber layer. The scanning electron microscopy (SEM) technique was conducted to investigate the impregnation of carbon nanofiber paper and FBG sensors by the resin during the VARTM process. The study shows that a complete penetration of the resin through carbon nanofiber paper and FBG sensors was achieved.

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