Abstract
A novel method to obtain independent strain and temperature measurements using embedded Fibre
Bragg Grating (FBG) in polymeric tensile test specimens is presented in this paper. The FBG strain and
temperature cross-sensitivity was decoupled using two single mode FBG sensors, which were embedded
in the specimen material with a certain angle between them. It is demonstrated that, during temperature
variation, both FBG sensors show the same signal response. However, for any applied load the signal
response is different, which is caused by the different levels of strain acting in each sensor. Equations to
calculate independently the strain and temperature are presented in the article, together with a measurement
resolution study.
This multi-parameter measurement method was applied to an epoxy tensile specimen, tested in a
unidirectional tensile test machine with a temperature controlled cabinet. A full calibration procedure
(temperature and strain) was performed to this material-sensor pair, where a calibration error < 1% was
achieved. This was followed by a strain-temperature test case, where multiple two loading/strain stages
of ε = 0.30% and ε = 0.50% were applied during a continuous variation of temperature, from 40 C to -10 C.
The consistency of the expected theoretical results with the calibration procedure and the experimental
validation shows that this proposed method is applicable to measure accurate strain and temperature
in polymers during static or fatigue tensile testing. Two different calibration protocols are
presented and analysed.
© 2016 Elsevier Ltd. All rights reserved.
Original language | English |
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Journal | Polymer Testing |
Volume | 50 |
Pages (from-to) | 125-134 |
Number of pages | 10 |
ISSN | 0142-9418 |
DOIs | |
Publication status | Published - 2016 |
Keywords
- Fibre Bragg grating sensors
- Strain and temperature measurement
- Polymer embedded sensors
- FBG multi-parameter measurement