Simultaneous Strain and Temperature Measurement Using a Single Fiber Bragg Grating Coated with a Thermochromic Material

Abstract

The objective of this project is to demonstrate simultaneous strain and temperature measurement using a single Fiber Bragg Grating (FBG). We discovered that the spectral bandwidth of a conventional FBG sensor can be modulated by coating the FBG sensor with a thermochromic material or embedding the FBG sensor in a composite laminate. Since the bandwidth modulation of the FBG sensor is temperature and strain dependent, we introduced the FBG spectral bandwidth as an additional sensor parameter that can be combined with the Bragg wavelength for simultaneous strain and temperature measurements. Thermal-mechanical tests were conducted to validate this principle and a data analysis algorithm was developed to extract the temperature and strain values simultaneously from the spectral parameters of the FBG sensor. For an FBG sensor coated with thermochromic material, the measurement errors for the axial load and the temperature were found to be +/- 4gm and +/-4 deg C, respectively. For an FBG sensor embedded in a composite laminate, the measurement errors,within one standard deviation, for the strain and temperature measurements were found to be +/- 62 and +/-1.94 deg C, respectively. This project supported two graduate students and resulted in one journal paper published,one journal manuscript submitted, two conference presentations, and one masters thesis.

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Document Details

Document Type
Technical Report
Publication Date
Mar 27, 2017
Accession Number
AD1032589

Entities

People

  • Haiying Huang

Organizations

  • University of Texas at Arlington

Tags

Communities of Interest

  • Sensors

DTIC Thesaurus Topics

  • Algorithms
  • Axial Loads
  • Bandwidth
  • Basic Programming Language
  • Birefringence
  • Bragg Gratings
  • Composite Materials
  • Curve Fitting
  • Data Analysis
  • Detectors
  • Fiber Bragg Gratings
  • Fibers
  • Laminates
  • Light Sources
  • Materials
  • Materials Processing
  • Measurement
  • Optical Fibers
  • Optical Materials
  • Polarization
  • Spectrum Analyzers
  • Spreadsheet Software
  • Stresses
  • Thermochromic Materials
  • Three Dimensional

Fields of Study

  • Physics

Readers

  • Mechanical Engineering/Mechanics of Materials.
  • Optical Fiber Sensing and Electromagnetic Propagation.
  • Thermal Physics or Thermal Science.