Damage Detection of CFRP Plates by Full-Spectral Analysis of a Fibre Bragg Grating Sensor Signal

Journal Article · Fri May 28 00:00:00 EDT 2010 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3455466· OSTI ID:21366745

Mizutani, Yoshihiro ^[1]; Groves, Roger M ^[1]

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1. Optical Non-Destructive Testing Laboratory, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2600 GB Delft (Netherlands)

This paper describes the measurement of average strain, strain distribution and vibration of cantilever beam made of Carbon Fiber Reinforced Plastics (CFRP), using a single Fibre Bragg Grating (FBG) sensor mounted on the beam surface. Average strain is determined from the displacement of the peak wavelength of reflected light from the FBG sensor. Unstrained reference FBG sensors were used to compensate for temperature drift and the photoelastic coefficient (P{sub e}), which was used to calculate the gauge factor. Measured strains agree with those measured by a resistance foil strain gauge attached to the sample. Stress distributions are measured by monitoring the variation in the full width half maximum (FWHM) values of the reflected spectrum, using a proposed optical analytical model, described in the paper. FWHM values were measured for both the cantilever test beam and a for a reference beam, loaded using a four-point bending rig. The trend of the stress distribution for the test beam matches with our analytical model, however with a relatively large noise present in the experimentally determined data. The vibration of cantilever beam was measured by temporal analysis of the peak reflection wavelength. This technique is very stable as measurements are not affected by variations in the signal amplitude. Finally an application of FBG sensors for damage detection of CFRP plates is demonstrated, by measuring the average strain and natural frequency. With small defects of different sizes applied to the CFRP plate, average strains were seen to increase with damage size and the natural frequency decreased with damage size.

• OSTI ID: 21366745
• Journal Information: AIP Conference Proceedings, Vol. 1253, Issue 1; Conference: 9. international conference on vibrational measurements by laser and non-contact techniques and short course, Ancona (Italy), 22-25 Jun 2010; Other Information: DOI: 10.1063/1.3455466; (c) 2010 American Institute of Physics; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
CARBON FIBERS
DAMAGE
FOILS
PLATES
REINFORCED PLASTICS
SENSORS
SIGNALS
STRAIN GAGES
STRESSES
FIBERS
MATERIALS
MEASURING INSTRUMENTS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
PLASTICS
POLYMERS
REINFORCED MATERIALS
SYNTHETIC MATERIALS