Simultaneous measurement of temperature and strain in glass fiber/epoxy composites by embedded fiber optic sensors: I. Cure monitoring

Leonardo D'Acquisto, Roberto Montanini

Risultato della ricerca: Article

48 Citazioni (Scopus)

Abstract

In this paper (Part I) the use of fiber optic sensors for real-time monitoring of the cure kinetics of GFRP composites is explored. The proposed sensing system allows the simultaneous measurement of both temperature and strain by monitoring the change in reflected wavelength from two coupled fiber Bragg grating (FBG) sensors that have been embedded into the composite laminate. Instrumented GFRP laminates with 12, 18 and 24 reinforcing plies, respectively, were prepared by means of the vacuum bagging technique. Samples were cured in a thermally controlled oven at 80 degrees C and 30 kPa for 240 min (isothermal stage) and then cooled down to ambient temperature by turning off the heating source (cooling stage). The obtained results, combined with proper data post-processing, have proven the effectiveness and potentiality of the proposed sensing system to measure the progression of the composite cure kinetics. It was shown that temperature within the specimen can differ significantly from the set-point temperature inside the oven because of the heat released during the exothermal reticulation of the epoxy resin. The combined sensing system also allowed the residual strain accumulated within the composite during the cooling stage to be accurately measured. Once the laminate had been cured, the embedded optical sensing system reveals itself purposeful for real-time structural health monitoring and damage assessment of the finished component. This aspect is discussed with more detail in the accompanying paper (Part II).
Lingua originaleEnglish
pagine (da-a)1718-1726
RivistaSmart Materials and Structures
Volume16
Stato di pubblicazionePublished - 2007

Fingerprint

Fiber optic sensors
glass fibers
Glass fibers
fiber optics
laminates
Laminates
composite materials
Monitoring
sensors
ovens
Composite materials
Ovens
damage assessment
Cooling
Epoxy Resins
cooling
Optical fiber coupling
Temperature
Kinetics
temperature

All Science Journal Classification (ASJC) codes

  • Signal Processing
  • Electrical and Electronic Engineering
  • Mechanics of Materials
  • Condensed Matter Physics
  • Materials Science(all)
  • Civil and Structural Engineering
  • Atomic and Molecular Physics, and Optics

Cita questo

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title = "Simultaneous measurement of temperature and strain in glass fiber/epoxy composites by embedded fiber optic sensors: I. Cure monitoring",
abstract = "In this paper (Part I) the use of fiber optic sensors for real-time monitoring of the cure kinetics of GFRP composites is explored. The proposed sensing system allows the simultaneous measurement of both temperature and strain by monitoring the change in reflected wavelength from two coupled fiber Bragg grating (FBG) sensors that have been embedded into the composite laminate. Instrumented GFRP laminates with 12, 18 and 24 reinforcing plies, respectively, were prepared by means of the vacuum bagging technique. Samples were cured in a thermally controlled oven at 80 degrees C and 30 kPa for 240 min (isothermal stage) and then cooled down to ambient temperature by turning off the heating source (cooling stage). The obtained results, combined with proper data post-processing, have proven the effectiveness and potentiality of the proposed sensing system to measure the progression of the composite cure kinetics. It was shown that temperature within the specimen can differ significantly from the set-point temperature inside the oven because of the heat released during the exothermal reticulation of the epoxy resin. The combined sensing system also allowed the residual strain accumulated within the composite during the cooling stage to be accurately measured. Once the laminate had been cured, the embedded optical sensing system reveals itself purposeful for real-time structural health monitoring and damage assessment of the finished component. This aspect is discussed with more detail in the accompanying paper (Part II).",
keywords = "BRAGG GRATING SENSORS; FIBRE/EPOXY COMPOSITES; EPOXY-RESIN; SITU; THERMOSET; SYSTEM",
author = "Leonardo D'Acquisto and Roberto Montanini",
year = "2007",
language = "English",
volume = "16",
pages = "1718--1726",
journal = "Smart Materials and Structures",
issn = "0964-1726",
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TY - JOUR

T1 - Simultaneous measurement of temperature and strain in glass fiber/epoxy composites by embedded fiber optic sensors: I. Cure monitoring

AU - D'Acquisto, Leonardo

AU - Montanini, Roberto

PY - 2007

Y1 - 2007

N2 - In this paper (Part I) the use of fiber optic sensors for real-time monitoring of the cure kinetics of GFRP composites is explored. The proposed sensing system allows the simultaneous measurement of both temperature and strain by monitoring the change in reflected wavelength from two coupled fiber Bragg grating (FBG) sensors that have been embedded into the composite laminate. Instrumented GFRP laminates with 12, 18 and 24 reinforcing plies, respectively, were prepared by means of the vacuum bagging technique. Samples were cured in a thermally controlled oven at 80 degrees C and 30 kPa for 240 min (isothermal stage) and then cooled down to ambient temperature by turning off the heating source (cooling stage). The obtained results, combined with proper data post-processing, have proven the effectiveness and potentiality of the proposed sensing system to measure the progression of the composite cure kinetics. It was shown that temperature within the specimen can differ significantly from the set-point temperature inside the oven because of the heat released during the exothermal reticulation of the epoxy resin. The combined sensing system also allowed the residual strain accumulated within the composite during the cooling stage to be accurately measured. Once the laminate had been cured, the embedded optical sensing system reveals itself purposeful for real-time structural health monitoring and damage assessment of the finished component. This aspect is discussed with more detail in the accompanying paper (Part II).

AB - In this paper (Part I) the use of fiber optic sensors for real-time monitoring of the cure kinetics of GFRP composites is explored. The proposed sensing system allows the simultaneous measurement of both temperature and strain by monitoring the change in reflected wavelength from two coupled fiber Bragg grating (FBG) sensors that have been embedded into the composite laminate. Instrumented GFRP laminates with 12, 18 and 24 reinforcing plies, respectively, were prepared by means of the vacuum bagging technique. Samples were cured in a thermally controlled oven at 80 degrees C and 30 kPa for 240 min (isothermal stage) and then cooled down to ambient temperature by turning off the heating source (cooling stage). The obtained results, combined with proper data post-processing, have proven the effectiveness and potentiality of the proposed sensing system to measure the progression of the composite cure kinetics. It was shown that temperature within the specimen can differ significantly from the set-point temperature inside the oven because of the heat released during the exothermal reticulation of the epoxy resin. The combined sensing system also allowed the residual strain accumulated within the composite during the cooling stage to be accurately measured. Once the laminate had been cured, the embedded optical sensing system reveals itself purposeful for real-time structural health monitoring and damage assessment of the finished component. This aspect is discussed with more detail in the accompanying paper (Part II).

KW - BRAGG GRATING SENSORS; FIBRE/EPOXY COMPOSITES; EPOXY-RESIN; SITU; THERMOSET; SYSTEM

UR - http://hdl.handle.net/10447/3655

M3 - Article

VL - 16

SP - 1718

EP - 1726

JO - Smart Materials and Structures

JF - Smart Materials and Structures

SN - 0964-1726

ER -